A single-institution experience with concurrent capecitabine and radiation therapy in gastrointestinal malignancies.

PURPOSE: We report our clinical experience with 32 patients receiving concurrent irradiation and capecitabine. METHODS AND MATERIALS: Medical records of patients with gastrointestinal malignancies treated with radiation and capecitabine therapy were reviewed. RESULTS: The population consisted of 20 males and 12 females, with a median age of 67.5 years (45-84 years) and adequate hepatic and bone marrow function. Histology was adenocarcinoma in all patients, except two with esophageal squamous carcinoma. Twenty-one patients received the regimen as adjuvant therapy, three received preoperative therapy, and 8 patients received therapy for palliation. The median dose of capecitabine was 1600 mg/m(2)/day (1200-2500 mg/m(2)/day) orally for 5 days per week for the duration of radiation therapy. Thirty patients received a total dose ranging from 45 Gy to 64 Gy over 4-6 weeks. Two previously radiated patients received total doses of 29.9 Gy and 46 Gy. Grade 3/4 toxicities observed were neutropenia in 3 patients and diarrhea, thrombocytopenia, fatigue, and myocardial infarction in 1 patient each. No treatment-related mortality was observed. Twenty of 21 patients (95.2%) who received adjuvant therapy continue to be in complete remission. Four of 11 (36%) evaluable patients demonstrated a response. CONCLUSION: Concurrent capecitabine and radiation were very well tolerated and warrant further investigation in prospective trials.

Bryostatin 1 induces differentiation and potentiates the antitumor effect of Auristatin PE in a human pancreatic tumor (PANC-1) xenograft model.

Pancreatic cancer has the worst prognosis of all cancers with a dismal 5-year survival rate. Hence, there is a tremendous need for development of new and effective therapy for this tumor. In an earlier study we reported a potent antitumor activity of Auristatin PE (AuriPE) against pancreatic tumor. In addition, we have also reported that bryostatin 1 (bryo1) induces differentiation of leukemia cells, but the effect of bryo1 has not been investigated in pancreatic tumors. This is the first report where we demonstrate that bryo1 induces differentiation and potentiates the antitumor effect of AuriPE in a human pancreatic tumor (PANC-1) xenograft model. A xenograft model was established by injecting the PANC-1 cells s.c. in severe combined immune deficient (SCID) mice. After development of the s.c. tumors, tumors were dissected and small fragments were transplanted in vivo to new SCID mice, with a success rate of 100% and a doubling time of 4.8 days. The SCID mouse xenograft model was used to test the in vivo differentiation effect of bryo1 and its efficacy when given alone or in combination with AuriPE. Sections from paraffin-embedded tumors excised from untreated (control) SCID mice revealed typical poorly differentiated adenocarcinoma of the pancreas. Interestingly, sections of s.c. tumors taken from bryo1-treated mice revealed carcinomas that were much lower grade and less aggressive, and displayed prominent squamous and glandular differentiation. In this study, the tumor growth inhibition (T/C), activity score and cure rate for bryo1, AuriPE and bryo1+AuriPE were 80%, (+) and 0/4; 0.0%, (++++) and 3/5; and 0.0%, (++++) and 3/4, respectively. Mice treated with either AuriPE or bryo1+AuriPE were free of tumors for more than 150 days and were considered cured. The use of bryo1 as a novel differentiating agent and its combination with AuriPE should be further explored for the treatment of adenocarcinoma of the pancreas.

Phase II study of gemcitabine and cisplatin in the treatment of patients with advanced pancreatic carcinoma.

BACKGROUND: Pancreatic carcinoma is considered among the most chemoresistant of human malignancies. The most commonly used cytotoxic single agents, 5-fluorouracil and 2'-deoxy-2',2'-difluorocytidine (gemcitabine), have objective response rates of less than 10% in large studies. Hypothesizing noncross resistance and a synergistic interaction between gemcitabine and cisplatin, early clinical studies have demonstrated significant activity with this combination in patients with several types of malignant disease. A Phase II study was undertaken to determine the efficacy of gemcitabine in combination with cisplatin in patients with locally advanced and metastatic pancreatic carcinoma based on these considerations. METHODS: The eligibility criteria included histologically confirmed, locally advanced, unresectable or metastatic exocrine carcinoma of the pancreas with no prior gemcitabine therapy; prior adjuvant therapy was allowed provided the last day of therapy was at least 6 months prior to starting treatment; clinically measurable or evaluable disease; a Southwest Oncology Group scale performance status of 0-2; a life expectancy of > 12 weeks; and adequate bone marrow, hepatic, and renal function. A total of 42 patients, 4 patients with locally advanced, unresectable disease and 38 patients with metastatic disease, were treated and received a total of 211 cycles of therapy between May 1997 to March 1999. The median age of patients was 61.5 years. The patients were treated in the outpatient setting with a combination of gemcitabine 1,000 mg/M(2) intravenously over 30 minutes administered on Days 1, 8, and 15 of each cycle and cisplatin 50 mg/M(2) intravenously administered after gemcitabine infusion on Days 1 and 15 with adequate prehydration accompanied by adequate urinary output. Cycles were repeated every 28 days. Response and toxicity were assessed according to World Health Organization and standard criteria. RESULTS: The complete and partial response rate among all 42 registered patients was 11 of 42 patients (26%; 95% confidence interval, 0.14-0.42). Stabilization of disease was seen in 15 patients (38%). Two additional patients with metastatic disease who achieved major responses to chemotherapy were rendered free of disease surgically, achieving a complete response status. The median overall survival was 7.1 months (95% confidence interval [CI], 6.3-9.1 months), with 64% of patients alive at 6 months and 19% of patients alive at 12 months. The median time to disease progression was 5.4 months (range, 0.9-20.8 months). Major toxicities were neutropenia and thrombocytopenia, with one episode of neutropenic fever. CONCLUSIONS: The combination of gemcitabine and cisplatin appeared to have significantly greater activity than single-agent gemcitabine in this Phase II study, with tolerable toxicity. The antitumor activity of this combination needs to be confirmed in multi-institutional or comparative trials.

CD95-related apoptotic machinery is functional in pancreatic cancer cells.

The CD95 (FAS, Apo-1) system is a major death pathway in normal and tumor cells. Recent evidence indicates that pancreatic cancer cells express CD95R and CD95L but are insensitive to CD95-mediated apoptosis. Here we show that treatment of human pancreatic cancer cells with RNA synthesis inhibitor actinomycin D (ActD) converted the phenotype of cancer cells from CD95 resistant to CD95 sensitive. Flow cytometric analysis demonstrated that all pancreatic cancer cell lines studied responded with cell surface CD95R and CD95L upregulation to bleomycin treatment, and PANC1 (mt p53) cells demonstrated a dose-dependent response to interferon gamma and bleomycin treatment with CD95R and CD95L up-regulation. However, only bleomycin sensitized PANC1 cells to CD95-mediated apoptosis. Taxol sensitized PANC1 and HPAC cells to CD95-mediated apoptosis without surface up-regulation of CD95R. These data suggest that pancreatic cancer cells possess a p53-independent mechanism of CD95R and CD95L surface upregulation and that surface expression of CD95R is not predictive of apoptotic function. Protein extracts of HPAC and PANC1 cells treated for 24 hours with a combination of ActD/agonist anti-CD95 antibodies demonstrated significantly higher Acetyl-Asp-Glu-Val-Asp-ase (DEVDase) cleavage activity (caspase 3-like activity) than extracts from cells treated with ActD only. In the present study, we also investigated the time kinetics of DEVDase (caspase 3-like) activation in PANC1 (mt p53) and HPAC (wt p53) pancreatic cancer cell lines. We found that DEVDase activity in PANC1 cells responds to ActD and ActD/anti-CD95 antibodies earlier than in HPAC cells; however, at 24 hours HPAC cells demonstrated much stronger activation. Cytosolic protein extracts from untreated cells did not influence caspase 3-like activity when added to extracts from the ActD/anti-CD95 antibody-treated cells. Collectively, these data suggest that pancreatic cancer cells have functional CD95-related apoptotic machinery with preserved apoptotic signal transduction, CD95R upregulation. and caspase activation. However, this system is blocked by some unknown protein(s) that is either located in the organelle fraction of the cell and/or requires an intact cell for manifestation of its activity.

Cost analysis of pancreatic carcinoma treatment.

BACKGROUND: Pancreatic carcinoma is a major health issue and financial burden to society. To improve the quality and efficiency of care delivered, it is essential for health care providers to have a good understanding of the cost of treatment. METHODS: The authors examined the facility-based costs and survival of 103 patients with pancreatic carcinoma who were treated at the Karmanos Cancer Institute between January 1992 and September 1998. Longitudinal cost data for each patient were obtained, and from those data, 6-month, 1-year, and lifetime total treatment costs were calculated. RESULTS: The average 6-month, 1-year, and lifetime total treatment costs were $37,327, $42,218, and $48,803, respectively, and the median survival was 7 months. In univariate analyses, the disease stage at diagnosis was a highly significant predictor of total cost. Patients with metastatic disease had the lowest cost, and patients with resectable disease had the highest cost. In multivariate analyses controlling for disease stage, treatment strategies and dual insurance coverage were also important predictors of costs but patient age, race, and gender were not predictive. Disease stage also was highly predictive of survival. In a multivariate analysis controlling for disease stage, chemotherapy and radiation therapy were correlated with longer survival, whereas resection and palliative bypass surgery were not. CONCLUSIONS: The costs of treating patients with pancreatic carcinoma are considerable, even though survival duration typically is short. Disease stage was the most dominating factor determining costs and survival. After controlling for disease stage, chemotherapy, surgery, and dual insurance coverage were also significantly associated with higher cost of care. However, in survival analyses, only chemotherapy and radiation therapy were associated with a significant increase in patient survival.

Cisplatin, cytarabine, caffeine, and continuously infused 5-fluorouracil (PACE) in the treatment of advanced pancreatic carcinoma: a phase II study.

Encouraging results using cisplatin, cytarabine, and caffeine for the treatment of pancreatic carcinoma prompted a phase II study using these agents and adding continuous intravenous infusion (CI) 5-fluorouracil (5-FU) (PACE). Patients with advanced pancreatic adenocarcinoma who had not received prior cytotoxic therapy were eligible. Treatment consisted of the following: on day 1, the administration of cisplatin 100 mg/m2 IV, cytarabine 2 g/m2 IV every 12 hours x 2 doses, and caffeine 400 mg/m2 subcutaneously after each cytarabine dose; and on days 3 to 21, 5-FU 250 mg/m2/day given by CI. Cycles were repeated every 28 days. Thirty eligible patients were entered in the study. The median number of cycles received was three. Grade IV neutropenia and thrombocytopenia occurred in 53% and 27% of patients, respectively. Among 30 treated patients, complete remission (CR) was seen in 2 patients and partial remission (PR) in 3 patients, for an overall response rate of 16.7% (95% confidence interval 6.8-32.4%). The median survival was 5.0 months (range: 0.3-32.4 months) and 16.7% and 10% of patients were alive at 1 and 2 years. respectively. Changes in the serum level of CA 19-9 provided an early marker of response which translated in differences in survival. Those with increasing or decreasing/stable levels of CA 19-9 after the first cycle of therapy had median survivals of 1.7 and 8.3 months, respectively (p = 0.0002). Although PACE chemotherapy produced durable responses in pancreatic cancer, the toxicity was substantial. A modification of this regimen with newer, less toxic drugs may provide better results and reduced toxicity. Also, the monitoring of the serum CA 19-9 level may provide a means to assess response and predict survival.

Magnetic resonance imaging to measure therapeutic response using an orthotopic model of human pancreatic cancer.

Pancreatic cancer is one of the most incurable and lethal human cancers in the United States. To facilitate development of novel therapeutic agents, we previously established an orthotopic pancreatic tumor model that closely mimics the natural biological behavior of human pancreatic cancer. In this study, magnetic resonance imaging (MRI) techniques were developed to detect tumor formation noninvasively and monitor serially tumor growth kinetics in this orthotopic model used for experimental drug testing. By using an optimized T2-weighted imaging method, we were able to distinguish human pancreas cancer from normal mouse pancreas. Orthotopic tumor formation was detected as early as day 1 after tumor cell implantation with a tumor volume as small as 12 mm3. Mice with evidence of tumor were separated into four treatment groups: control, auristatin-PE, gemcitabine, and their combination. After treatment, the mice were imaged at least three times before termination of the experiment. Comparison between MRI tumor volume measurements and tumor weights made at biopsy resulted in a correlation coefficient of 0.98. The tumor growth curves constructed from serial magnetic resonance imaging (MRI) measurements clearly showed tumor growth inhibition in treated mice compared with the control group. As expected, the group treated with the combination had the highest response rate compared with either auristatin-PE or gemcitabine alone, and the data were statistically highly significant (p < 0.004). From these results, we conclude that noninvasive MRI can be used to monitor serially therapeutic response in this orthotopic human pancreatic tumor model and can be used in the future to evaluate novel antitumor agents before human studies.

Clonal preservation of human pancreatic cell line derived from primary pancreatic adenocarcinoma.

Adenocarcinoma of the pancreas generally remains an incurable disease by available treatment modalities, demanding the development of a suitable cell-culture/animal model and the discovery and evaluation of novel therapeutic agents. We report the clonal preservation of a human pancreatic cell line (KCI-MOH1) established from a 74-year-old African-American man diagnosed with pancreatic cancer. Initially the human primary tumor was grown as a xenograft in SCID mice and, subsequently, a cell line was established from tumors grown as a xenograft as reported in our earlier publication. The molecular characterization of the primary tumor, the tumors grown as xenograft, and the cell line all revealed similar genotypic properties. By using an automated DNA sequencer, a K-ras mutation (codon 12, GGT to CGT, Gly to Arg) was detected in the pancreatic tumor tissue taken from the patient, whereas no p53 mutation was detected. The same K-ras mutation and unaltered p53 was also found in the xenograft tumor and in the KCI-MOH1 cell line. Chromosome analysis of the cultured cells revealed: 42,XY,add(3)(p11.2),der(7)t(7;12) (p22;q12),-10,-12,add (14)(p11),-18,add (20)(q13),-22/84, idemx2, which is the same chromosome complement found in xenograft tumors. The KCI-MOH1 cell line grows well in tissue culture and forms tumors in the SCID mice when implanted subcutaneously, as well as in orthotopic sites. The KCI-MOH1 cell line-derived SCID mouse xenograft model was used for efficacy evaluation of bryostatin 1, auristatin-PE, spongistatin 1, and gemcitabine alone and in combination. Tumor growth inhibition (T/C expressed as percentage), tumor growth delay (T - C), and log 10 kill for these agents were 38%, 22 days, and 0.53; 15%, 30 days, and 0.80; 24%, 25 days, and 0.66; and 10%, 33 days, and 0.90, respectively. When given in combination, two of seven gemcitabine + auristatin-PE-treated animals were free of tumors for 150 days and were considered cured. Animals treated with a combination of bryostatin 1 and gemcitabine and a combination of spongistatin and gemcitabine produced remissions in only one of seven mice. From these results, we conclude that (a) this is the first study illustrating that clonal characteristics of primary pancreatic tumors remained unchanged when implanted in mice and as a permanent cell line grown in vitro; and (b) there is a synergistic effect between gemcitabine and selected marine products tested in this study, which is more apparent in the gemcitabine and auristatin-PE combination. The results of this preliminary study suggest that these agents should be explored clinically in the treatment of pancreatic cancer.

Molecular effects of taxol and caffeine on pancreatic cancer cells.

Pancreatic cancer is the fifth leading cause of cancer related deaths in the United States. Despite many recent advances in the treatment modalities, the mortality rate still remains very high. Paclitaxel (Taxol) and Caffeine have been used for the treatment of this disease, however the molecular mechanisms of these agents are not fully understood, which may be partly responsible for the failure of these agents in the treatment of pancreatic cancer. Human pancreatic adenocarcinoma cell lines, HPAC and PANC-1 containing wild-type and mutant p53 respectively, were used to investigate the effects of Taxol and Caffeine on cell growth, and their effects on the modulation of cell cycle and apoptosis related genes. Protein extracts from these cells treated with 100 nM of Taxol or 4 mM of Caffeine were subjected to Western blot analysis for this study. Drug treated cells were also analyzed to calculate the number of cells undergoing apoptosis. Dose and time dependent growth inhibition was observed in both PANC-1 and HPAC cells when treated with either Taxol or Caffeine. Western blot analysis showed an up-regulation of p21WAF1 in both cell lines treated with either Taxol or Caffeine. Furthermore, down-regulation of cyclin B and cdk1 was observed in Taxol and Caffeine treated HPAC cells. However, the results were drastically different in PANC-1 cells where cyclin B was down regulated only by Caffeine treatment and the level of cdk1 protein was undetectable in this cell line. Moreover, up-regulation of p53 and down-regulation of Bcl-2 was observed only in HPAC cells treated with Taxol. Apoptotic cell death analysis showed increasing number of cells undergoing apoptosis between 24 and 48 h of Caffeine treatment, however only Taxol showed greater than 50% cells under-going apoptosis only in HPAC cells. The up-regulation of p21WAF1 and down-regulation of cyclin B and cdk1 suggest their possible roles in G2/M cell cycle arrest caused by both Taxol and Caffeine as reported earlier. From these results we conclude that the differential molecular changes observed in this study may determine the cellular effects of these agents on pancreatic adenocarcinoma cells and that the effects of chemotherapeutic agents may be determined by the endogenous status of p53 mutation and, in turn, may determine the therapeutic effects of these agents in the treatment of pancreatic cancer.

Utility of fluorescence in situ hybridization in pancreatic ductal adenocarcinoma.

Often the diagnosis of pancreas cancer needs to be established from limited cytology specimens or small biopsies. Most ductal adenocarcinomas are histologically well to moderately differentiated and mimicked closely by pancreatitis, and therefore the microscopic diagnosis can be difficult. In addition, there appears to be significant heterogeneity in the outcome of the patients with pancreatic cancer, which cannot be predicted accurately by current prognosticators such as the grade and stage of the tumor. Therefore, there is need for methods that can be used as adjuncts to routine diagnostic and prognostic parameters. This study was designed to test the utility of the fluorescent in situ hybridization (FISH) method in identifying the molecular alterations, particularly the ones that have been detected with relatively high frequency in pancreas cancer. Formalin-fixed and paraffin-embedded tissues of 10 cases were enumerated for chromosome 7, 8, 17, 18, and 20 copy numbers by using alpha-satellite probes, and for c-myc by using a gene-specific probe. The number of signals per nucleus (reflecting chromosomal copy number and status of c-myc amplification) were counted in more than two areas containing 50-500 cells. Because of tumor heterogeneity, monosomy (loss of one chromosome copy) was defined arbitrarily as one signal in >25% of nuclei. C-myc amplification was defined as more than two gene copies in >20% of the cells. The most frequent signal losses were found in chromosomes 8 (four of 10 cases) and chromosome 17 (four of 10), followed by 20 (three of 10) and 18 (two of 10). No loss of chromosome 7 was detected. In contrast, gains in chromosome copy number were identified in only one of 10 tumors, which showed gain of both chromosome 7 and 18. Amplification of c-myc gene was detected in two of 10 cases, but neither of the two had aneuploidy for chromosome 8, where the c-myc gene is located. In addition, loss in c-myc signal was observed in one case that also showed loss of chromosome 8 copy number. FISH can be used to detect chromosomal changes in pancreatic cancer; abundance of lytic enzymes in this organ is not an impediment for the applicability of this technique. Therefore it can potentially be used in the future as an adjunct to the conventional diagnostic and prognostic markers. This study confirms that loss of chromosomes, particularly chromosomes 17 and 18, which carry the p53 and DCC genes, are common in pancreas cancer. Chromosome 20 is also frequently lost. In addition, in this study, alterations of chromosome 8, which is seen commonly in prostatic adenocarcinoma but has not been previously documented in pancreatic cancer, also was detected in five of 10 tumors. Furthermore, amplification of the c-myc gene, which is located in chromosome 8, was found in the two of the remaining five cases. Further studies are needed to confirm this high incidence of chromosome 8 and c-myc alterations and their possible role in the pathogenesis of pancreatic adenocarcinoma.

Structural alteration of p53 protein correlated to survival in patients with pancreatic adenocarcinoma.

Mutations in the p53 tumor-suppressor gene represent the most common form of genetic alterations found in diverse types of human cancer. The majority of the mutations occur in the core domain, which contains the sequence-specific DNA-binding site. They may result in loss of DNA binding and disability of transcriptional activation of genes involved in cell-cycle regulation. Analysis of the protein-structure model of these mutations can provide clues to the function of specific regions of p53 and to the clinical significance of p53 mutation. We examined 68 cases of pancreatic adenocarcinoma for p53 mutation and mutant protein-structure model by polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP), PCR-DNA sequencing, and computer-generated protein modeling. Twenty (29.41%) of 68 cases showed p53 mutation. Statistical analysis showed there was no significant difference in survival between p53 mutation and wild-type p53 (median survival, 12 vs. 13 months; p = 0.2034). Among p53 mutations, nine mutations were located at or near the DNA-binding site, and the protein structures of the DNA-binding site were changed. Patients in this group had a shorter median survival compared with those with mutation far from the DNA-binding site (median survival, 5 vs. 15 months; p = 0.0435). We conclude that detecting and modeling the p53 gene mutation may be used as a tool in predicting the clinical course of patients diagnosed with pancreatic adenocarcinoma.

Molecular analysis of the p53 gene in pancreatic adenocarcinoma.

Mutations in the p53 tumor suppressor gene are the most common genetic alterations found in human cancer. Most mutations are accompanied by stabilization of the protein, which renders the mutations detectable through immunohistochemical techniques. The immunoreactivity of p53, however, might not correlate with the result of p53 DNA sequencing. In order to explain the discrepancy, we studied the p53 expressions, mutations, and changes of the three-dimensional protein structure of mutant p53 in a series of 61 pancreatic adenocarcinoma specimens using immunohistochemistry, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), DNA sequencing, and computerized protein modeling. PCR-SSCP followed by DNA sequencing of the p53 gene showed mutations in 31.2% (19 of 61) of the pancreatic adenocarcinomas. Eight of 19 cases showed p53 immunopositivity. These mutations were located on the surface of the three-dimensional structure or formed unfolded proteins, which were easily recognized by the antibody. Among other mutations in which p53 was immunonegative, five cases with deletions and insertion caused frameshift and formation of severely truncated p53 protein structures unreactive with the antibody used. In three cases with point mutations, the mutant amino acids were located in the core of the tightly packed beta sandwich inaccessible to the antibody. Three silent mutations were immunonegative, corresponding with the absence of amino acid changes. These results strongly suggest that the analysis of a computer-generated p53 three-dimensional model based on DNA sequencing data can assist in evaluating the significance of p53 immunostaining and mutations for clinical applications.

An orthotopic model of human pancreatic cancer in severe combined immunodeficient mice: potential application for preclinical studies.

Pancreatic adenocarcinoma is one of the most incurable and least understood of all human cancers. It is the fourth leading cause of cancer-related mortality in males (after lung, prostate, and colon) and in females (after lung, breast, and colon) in the United States with <2-3% of patients surviving >5 years. In an attempt to search for more effective therapies for this disease, we report here, for the first time, an effective treatment, the combination of gemcitabine and auristatin-phenethylamine (PE), against an orthotopic implantation of a human pancreatic adenocarcinoma cell line (HPAC) in severe combined immunodeficient (SCID) mice. Tumor implantation was performed by injecting 100 microl of the HPAC cell suspension (1 x 10(6) cells) directly into the pancreas of 5-week-old SCID mice. After implantation, tumor formation was checked twice a week. All palpable tumors were detected within 21 days (100% take rate), and tumors were confirmed histologically to be pancreatic adenocarcinoma. For the subsequent efficacy trial, tumor-bearing SCID mice were randomized into four groups with five mice in each group. One served as a control, the second received gemcitabine alone (2.5 mg/kg/injection i.p.), the third received auristatin-PE alone (2.0 mg/kg/injection i.v.), and the fourth group received the combination of gemcitabine (i.p.) and auristatin-PE (1.5 mg/kg/injection i.v.). All animals were euthanized 7 days after the completion of their treatments, and the pancreases were resected. Histological examination revealed the tumors to be adenocarcinoma. The tumors were composed of diffuse sheets of cells interrupted by glandular spaces containing secretory material. Cytologically, the tumor cells were large, pleomorphic, and hyperchromatic. Many cells contained intracellular lumina containing mucin. Immunohistochemical studies showed strong p21WAF1 (p21) expression but no immunoreactivity with p53 and Her-2/neu antibodies. The mean pancreatic weight in the gemcitabine/auristatin-PE combination group was significantly (P = 0.014) lower (0.84 +/- 0.639 g) when compared with those of the control (2.91 +/- 1.19 g) and gemcitabine alone (1.84 +/- 0.796 g; P = 0.064) groups. In addition, the mean weight in the combination group approached statistical significance when compared with the auristatin-PE group alone (1.16 +/- 0.635 g; P = 0.028). We conclude that the combination of gemcitabine and auristatin-PE is an effective treatment against HPAC tumors in this xenograft model and more effective than treatment with either gemcitabine or auristatin-PE alone and could be considered for future animal studies with pancreas cancer and/or for human clinical trials.

Inhibition of pancreatic tumor cell growth in culture by p21WAF1 recombinant adenovirus.

New innovations are needed for the treatment of pancreatic cancer, as current treatments do not offer significant improvements in overall survival. p21WAF1--a tumor suppressor gene--acts as a downstream effector of p53 function and mediates G1 cell cycle arrest by inhibiting cyclin-dependent kinases, which promote cell growth. p21 expression has also been shown to increase more than 20-fold in senescent cells in culture. The replication-defective recombinant adenoviral system (rAd), a major innovation in gene transfer technology, has recently been used in gene therapy applications for various malignancies but not for pancreas cancer. In this study we used rAd-p21 in cell growth inhibition studies of pancreatic tumor cell lines in vitro to explore its potential as a prospective gene therapy for pancreatic adenocarcinoma. We studied two pancreatic cell lines in culture, HPAC and Hs766T. HPAC revealed higher endogenous levels of p21 gene expression at the protein and RNA levels compared to Hs766T. p21 induction was tested using different doses of rAd-p21 to establish an optimum dose for significant induction of p21 gene expression. Tumor cell growth in culture following rAd-p21 infection was also analyzed in both cell lines. HPAC and Hs766T cell lines showed a significant dose-dependent increase in p21 protein expression when infected with rAd-p21. Both cell lines showed significant growth arrest, but Hs766T showed less cell growth inhibition than HPAC cells. Flow cytometric cell cycle analysis of rAd-p21-infected cells showed a statistically significant increase in the number of cells in G0/G1 in HPAC cells. Similar results were also obtained in Hs766T cells, however, the data were not statistically significant. In conclusion, pancreatic tumor cell growth can be inhibited by rAd-p21 in vitro, with significant numbers of tumor cells reverting from S to G0/G1. Thus rAd-p21 may be effective as a candidate gene therapy for pancreatic cancer and should be further evaluated with in vivo studies.

Establishment of a human pancreatic tumor xenograft model: potential application for preclinical evaluation of novel therapeutic agents.

Adenocarcinoma of the pancreas is currently the fifth leading cause of death in the United States. It remains generally incurable by available treatment modalities. We report here on the characterization of a permanent pancreatic cell line (KCI-MOH1), established as a xenograft in severe combined immune deficient (SCID) mice, from a 74 year-old African American male patient diagnosed with pancreatic cancer. Sections from paraffin-embedded tumors excised from SCID mice revealed typical adenocarcinoma of the pancreas. Karyotypic analysis of cultured cells derived from tumors grown in SCID mice revealed a male karyotype with multiple clonal aberrations: 42, XY, add (3)(p11.2), der(7) t(7;12) (p22;q12), -10, -12, add (14)(p11), -18, add (20)(q13)-22/84, idemx2. Immunostaining of KCI-MOH1 tissues shows strong expression of p53 and p21 proteins. The xenograft model was established by transplanting the KCI-MOH1 cells subcutaneously (s.c.) in SCID mice. When the s.c. tumor was transplanted in vivo to other SCID mice, the success rate was 100%, with a doubling time of 8.5 days. The SCID mouse xenograft model was used to test the efficacy of selected standard chemotherapeutic drugs (taxol, gemcitabine, 5-fluorouracil, and Ara-C) and novel biological agents (Bryostatin 1 and Auristatin-PE). Results show that gemcitabine, Ara-C, and Bryostatin 1 were active against KCI-MOH1. The xenograft described herein can be used as an animal model to facilitate the development of novel therapeutic agents against human pancreatic cancers.

Molecular alterations associated with improved survival in pancreatic cancer patients treated with radiation or chemotherapy.

Multiple genetic alterations, several of which may be important prognostic markers, characterize the development of cancer in pancreas. We review our findings from previously published studies with regard to molecular alterations associated with survival differences in patients treated with conventional radiation and chemotherapies used as adjuvant or palliative therapy. K-ras-negative patients with pancreas cancer show improved survival with radiation therapy compared to K-ras-positive patients with pancreas cancer. p53 expression is associated with shorter survival when compared to no p53 expression in pancreas cancer patients treated with radiation therapy or chemotherapy. Pancreas cancer patients whose tumors express p21 show significant survival advantages when treated with chemotherapy or radiation therapy. An inverse relationship is observed with respect to p21 and p53 expression and clinical stage. Although stage and surgical resectability remain the most important variables with respect to pancreas cancer survival, these findings suggest promising opportunities for gene therapies designed to enhance p21 expression or restore wild-type K-ras or p53 function in pancreatic tumors.

The clinical significance of p21(WAF1/CIP-1) and p53 expression in pancreatic adenocarcinoma.

BACKGROUND: Wild-type p53 protein activates the WAF1/CIP-1 (p21) gene, leading to G1 arrest after DNA damage. The authors investigated the relation of p21 and p53 expression in pancreatic adenocarcinomas to disease stage, overall patient survival, and survival when chemotherapy or radiation therapy was given. METHODS: Paraffin embedded tissue sections of 75 ductal adenocarcinomas of the pancreas were immunostained for p53 and p21. Nuclear expression was scored as absent, focal (<10%), moderate (10-50%), or strong or diffuse (>50%). RESULTS: The median survival of patients whose pancreatic tumors expressed the p21 protein (43 of 75 cases, 57%) was better than that for patients whose tumors were p21 negative (32 of 75 cases, 43%) (median survival, 13.5 vs. 9.8 months, respectively; P = 0.23). No difference in survival was found with regard to p53 protein expression (43 of 75 cases, 57%); however, strong p53 expression was significantly associated with advanced disease stage (70% in Stage IV vs. 13-28% in lower stages). Expression of p21 correlated with earlier clinical stage. Stage specific comparisons showed a trend toward increased survival among p21 positive tumor patients diagnosed at clinical Stages I and III but not among those diagnosed at Stage IV. Adjuvant chemotherapy or radiation improved survival significantly if tumors expressed p21 or no p53. CONCLUSIONS: Expression of p21 is significantly associated with earlier clinical stage in pancreatic adenocarcinoma, perhaps accounting for the better survival observed in this patient group than among those whose tumors were p21 negative. Improved survival with either chemotherapy or radiation therapy was observed for patients whose tumors were p21 positive or p53 negative.

Relationship of family cancer history to the expression of p53, p21WAF-1, HER-2/neu, and K-ras mutation in pancreatic adenocarcinoma.

CONCLUSION: In our series of 81 cases, a history of family cancer was present in 52% of patients (42/81) with pancreatic cancer. Nine percent (7/81)had a family history of pancreatic cancer. Our studies suggest a possible relationship of family cancer history to the expression of p53 and p21WAF in pancreatic tumors, but show no relationship to the expression of HER-2/neu or to the prevalence of K-ras mutations. A lower incidence of p53 expression observed in patients with a family history of cancer suggests normal p53 protein is present in a majority of patients who develop pancreatic tumors related to other--as yet unidentified-inherited or familial risk factors. There was no significant difference in survival of pancreas cancer patients with and without a family history of cancer. However, survival in pancreas cancer patients may be influenced (improved) by p21WAF-1 expression. BACKGROUND: Pancreas cancer is the fifth leading cause of cancer deaths (27,800 deaths/yr) in the United States. Various risk factors, including cigarette smoking, high-fat diet, DDT exposure, chronic pancreatitis, and diabetes mellitus, have been associated with pancreatic carcinoma. A few studies have suggested a genetic predisposition or increased risk for pancreatic cancer within families, but the exact etiology is largely unknown. In a series of 81 patients with pancreatic carcinoma, we analyzed the status of K-ras gene mutations and the expression of P21WAF-1, p53, and HER-2/neu protein to identify possible molecular associations in pancreas cancer cases of these molecular markers to family histories of cancer and pancreas cancer. METHODS: Paraffin-embedded tissue sections from 81 cases of pancreatic adenocarcinoma were used for DNA extraction and immunohistochemical staining. K-ras mutation was studied by single-stranded conformation polymorphism (SSCP) and slot-blot allele-specific oligonucleotide (ASO) hybridization of PCR-amplified DNA product. Overexpression (aberrant expression) of p53, p21WAF-1, and HER-2/neu was documented by scoring nuclear localized p53, p21WAF-1 protein and cell membrane expression of HER-2/neu after immunostaining with gene product-specific monoclonal antibodies (MAbs). RESULTS: Forty-two (42) of 81 patients studied in this series had a history of cancer in their families (52%). Seven of those 42 had a history of pancreatic carcinoma (17% or 9% of total cases). The incidence of K-ras mutation and the expression of p21WAF-1 and HER-2/neu in patient groups with and without a family history of cancer was not statistically different (83 vs 74%, p = 0.416; 57 vs 41%, p = 0.184; and 83 vs 81%, p = 1.000, respectively). However, the incidence of p53 expression was significantly lower in patients with a family history of cancer (40 vs 72%, p = 0.007). There was no statistical difference in survival of patients with a family history of cancer in relation to either K-ras mutation, p53 expression, p21, or HER-2/neu expression. However, patients lacking a family history of cancer showed improved survival trends in relation to p21 expression (median survival of 16 vs 8 mo, p = 0.029).

Mutations in the arginine-rich protein gene (ARP) in pancreatic cancer.

The ARP gene encodes a highly conserved arginine-rich protein from chromosomal band 3p21.1. At the cytogenetic level this region is frequently deleted in a variety of different solid tumors, although not in pancreatic cancer. We have reported the presence of a specific mutation (ATG50-->AGG) or deletion of codon 50 of the ARP gene in different tumor types (Shridhar et al., 1996, 1996a). In the present study, we have observed mutations involving codon 50 in 11 of 37 pancreatic tumors. The frequency of codon 50 mutation is roughly the same in pancreatic tumors as in the other types of tumors previously examined. In addition, we have detected mutations at codon 51 in multiple PCR subclones in two other pancreatic tumors. Mutations in the ARP gene are thus commonly observed in pancreatic cancer, as well as many other cancers.

Prevalence and clinical significance of combined K-ras mutation and p53 aberration in pancreatic adenocarcinoma.

CONCLUSION: This study could not attribute survival differences to the coincident acquisition of two common genetic alterations, K-ras mutation and p53 overexpression in pancreatic adenocarcinoma patients. Additionally, our data indicate the converse to be true: Those patients lacking both K-ras mutation and aberrant p53 expression showed the shortest survival when compared with cases showing either alteration or both. This study also showed the negative effect of K-ras mutation and p53 expression on pancreas cancer patients' survival after treatment with either radiation therapy or chemotherapy. BACKGROUND: Mutations of the oncogene K-ras at codon 12 are reported to be the most common genetic alteration in pancreatic carcinoma, whereas either overexpression or mutation of the tumor suppressor p53 gene is considered the most common genetic alteration in neoplasia of all types. p53 overexpression has been attributed to survival differences in pancreatic carcinoma, but such association is still controversial. No studies have fully documented the combined incidence of K-ras and p53 alterations in pancreatic adenocarcinoma, or their combined effect on patient survival in a large case series. The influence of radiation or chemotherapy in groups showing both, either, or neither mutation is also undocumented. METHODS: Paraffin-embedded tissue sections from 76 cases of pancreatic adenocarcinoma were cut for DNA extraction for K-ras analysis and immunohistochemical staining for aberrant p53 expression. K-ras mutation was determined by single-strand conformation polymorphism (SSCP) and slot-blot allele-specific oligonucleotide (ASO) hybridization of PCR-amplified DNA product p53 expression was scored on the basis of percent nuclear staining with the MAb DO7. RESULTS: Sixty-four of 76 cases (84%) showed K-ras mutation, p53 expression, or both, K-ras was mutated in 55 of 76 cases (72%). p53 was expressed in 33 of 76 cases (43%). Twenty-four of 76 cases (31%) showed both K-ras mutation and p53 expression. The presence of both alterations was not related to significant differences in tumor grade, stage, or survival compared to either alteration alone. A sizable subset (16% of cases) lacked either alteration, and surprisingly, this group showed the shortest median survival compared to those with K-ras mutation, p53 expression, or both (p = 0.024). Patients whose tumors were K-ras-negative showed the greatest difference in median survival with radiation therapy (median survival 30.8 mo vs 7.8 mo with no radiation, p = 0.005).