Primary pancreatic cancer of the jejunum: a case report and brief review of literature.

The variable clinical presentation of heterotopic pancreatic (HP) tissue and its malignant transformation makes the diagnosis very challenging. These lesions are very rare, usually not suspected upon initial presentation and for the most part, are diagnosed incidentally on review of pathology following surgical resection. In this study, we are reporting an adenocarcinoma arising from jejunal heterotopic pancreatic tissue in a 59-year-old female and a brief review of previously reported cases.

Determining risk of biochemical recurrence in prostate cancer by immunohistochemical detection of PTEN expression and Akt activation.

PURPOSE: A considerable fraction of patients who undergo radical prostatectomy as treatment for primary prostate cancer experience biochemical recurrence detected by elevated serum levels of prostate-specific antigen. In this study, we investigate whether loss of expression of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and the phosphorylated form of the cell survival protein Akt (pAkt) predicts biochemical recurrence. EXPERIMENTAL DESIGN: Expression of PTEN and pAkt was detected by immunohistochemistry in paraffin-embedded prostate cancer tissue obtained from men undergoing radical prostatectomy. Outcome was determined by 60-month follow-up determining serum prostate-specific antigen levels. RESULTS: By itself, PTEN was not a good predictor of biochemical recurrence; however, in combination with pAkt, it was a better predictor of the risk of biochemical recurrence compared with pAkt alone. Ninety percent of all cases with high pAkt and negative PTEN were recurrent whereas 88.2% of those with low pAkt and positive PTEN were nonrecurrent. In addition, high Gleason scores resulted in reduced protection from decreased pAkt and increased PTEN. By univariate logistic regression, pAkt alone gives an area under the receiver-operator characteristic curve of 0.82 whereas the area under the receiver-operator characteristic curve for the combination of PTEN, pAkt, and Gleason based on a stepwise selection model is 0.89, indicating excellent discrimination. CONCLUSIONS: Our results indicate that loss of PTEN expression, together with increased Akt phosphorylation and Gleason score, is of significant predictive value for determining, at the time of prostatectomy, the risk of biochemical recurrence.

Phosphorylation of Akt (Ser473) is an excellent predictor of poor clinical outcome in prostate cancer.

We previously showed, by immunohistochemistry with phospho-specific antibodies, increased phosphorylation (activation) of Akt (Ser(473)) [phosphorylated Akt (pAkt)] in high-Gleason grade prostate cancer (Malik SN, et al., Clin Cancer Res 2002;8:1168-71). Elevation of pAkt was accompanied by decreased phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 (Thr(202)/Tyr(204)) [phosphorylated ERK (pERK)], indicative of inactivation. In this report, we determined whether increased pAkt and decreased pERK predicted clinical outcome. Prostate-specific antigen (PSA) failure (detectable and rising PSA) versus PSA non-failure (undetectable PSA 5 years after prostatectomy) was used as a surrogate for clinical outcome. Prostate tumors from cases of PSA failure versus non-failure were stained for pAkt and pERK. A significant increase in mean pAkt staining (P < 0.001) in the PSA failures versus non-failures was seen based on the Wilcoxon signed ranks test [222.18 +/- 33.9 (n = 37) versus 108.79 +/- 104.57 (n = 16)]. Using the best-fitting multiple logistic regression equation, a 100-point increase in pAkt staining resulted in a 160% increase in the odds of being a PSA failure. There was decreased staining for pERK in PSA failures versus non-failures: a 100-point decrease resulted in an 80% increase in the odds of being a PSA failure. Each of these effects assumed the other biomarker was held constant. The area under the receiver-operating characteristic curve for these two biomarkers predicting PSA failure was 0.84, indicating excellent discrimination between PSA failure and non-failure cases. These data indicate that increased pAkt, alone or together with decreased pERK, is an important predictor of probability of PSA failure. However, pERK alone was not a significant predictor of PSA failure.

Antitumor activity of a recombinant soluble betaglycan in human breast cancer xenograft.

We have demonstrated previously that ectopic expression of a soluble betaglycan, also known as transforming growth factor (TGF) beta type III receptor, can suppress the malignant properties of human carcinoma cells by antagonizing the tumor-promoting activity of TGF-beta (A. Bandyopadhyay et al., Cancer Res., 59: 5041-5046, 1999). In the current study, we investigated the potential therapeutic utility of a recombinant preparation of human and rat soluble betaglycan (sBG). Purified recombinant human sBG showed similar properties to its rat counterpart (M. M. Vilchis-Landeros et al., Biochem J., 355: 215-222, 2001). It bound TGF-beta with high affinity and isoform selectivity and neutralized the activity of TGF-beta(1) in two bioassays. Peritumoral (50 micro g/tumor, twice a week) or i.p. (100 micro g/animal, every alternate day) injection of sBG into human breast carcinoma MDA-MB-231 xenograft-bearing athymic nude mice significantly inhibited the tumor growth. The administration of sBG also reduced metastatic incidence and colonies in the lungs. The tumor-inhibitory activity of sBG was found to be associated with the inhibition of angiogenesis. Systemic sBG treatment significantly reduced tumor microvessel density detected with histological analyses and CD-31 immunostainings, as well as tumor blood volume measured with hemoglobin content. In an in vitro angiogenesis assay, treatment with the recombinant sBG significantly reduced the ability of human dermal microvascular endothelial cells to form a capillary tube-like structure on Matrigel. These findings support the conclusion that sBG treatment suppresses tumor growth and metastasis, at least in part by inhibiting angiogenesis. As such, it could be a useful therapeutic agent to antagonize the tumor-promoting activity of TGF-beta.

Autocrine-mediated ErbB-2 kinase activation of STAT3 is required for growth factor independence of pancreatic cancer cell lines.

Pancreatic ductal adenocarcinoma (PDAC) cell lines, MIA PaCa-2, and UK Pan-1, were used to investigate the role of ErbB2 in PDAC oncogenesis. Both these cell lines exhibit exogenous growth factor-independent proliferation that was attributed to the production of autocrine growth factors and/or overexpression of growth factor receptors. The exogenous growth factor-independent phenotype displayed by these PDAC cell lines was dependent on ErbB2 kinase activity since treatment of cells with tyrphostin AG879 prevented serum-free media (SFM) induction of cell proliferation. We determined that ErbB2 kinase contributed to aberrant cell cycle regulation in PDAC through the induction of cyclin D1 levels and the suppression of p21(Cip1) and p27(Kip1). Inhibition of ErbB2 kinase led to cell cycle arrest marked by an increased association of p27(Kip1) with cdk2 and reduced levels of phosphorylated pRb. We further observed constitutive STAT3 activation in the PDAC cell lines and an increase in STAT3 activation upon stimulating quiescent cells with SFM. Inhibitors of ErbB2 kinase blocked STAT3 activation, whereas inhibition of EGFR kinase led to a slight reduction of STAT3 activation. STAT3 was coimmunoprecipitated with ErbB2. SFM stimulation caused an increase in the association of ErbB2 and STAT3, which was blocked by inhibition of ErbB2 kinase. Expression of a STAT3 dominant negative prevented SFM-stimulated cell proliferation of MIA PaCa-2 cells, suggesting that activation of STAT3 by ErbB2 is required for a growth factor-independent phenotype of these cells. Consistent with this observation in PDAC cell lines, we found that most PDAC tumor specimens (10 of 11) showed constitutive activation of STAT3 and that ErbB2 was readily detected in most of these tumors (nine of 11). We believe that these findings indicate a novel mechanism of oncogenesis in PDAC and may suggest future therapeutic strategies in the treatment of PDAC.

Extracellular domain of TGFbeta type III receptor inhibits angiogenesis and tumor growth in human cancer cells.

TGFbeta overexpression in human cancer cells has been shown to promote tumor progression. In the present study, we sought to determine whether sequestration of endogenous TGFbeta by the expression of a soluble TGFbeta type III receptor (sRIII), can reduce malignancy in human carcinoma cells and whether the tumor-suppressive activity of sRIII is associated with the inhibition of angiogenesis. Ectopic expression of sRIII significantly inhibited the growth of tumors formed by human colon carcinoma HCT116 and breast carcinoma MDA-MB-435 cells in nude mice. It also reduced the metastatic potential of the MDA-MB-435 cells. Thus, endogenous TGFbeta appears to be necessary for the progression of these two carcinomas. Furthermore, when the tumor cells were mixed with Matrigel and embedded subcutaneously in nude mice, the blood volume in Matrigel plugs containing sRIII-expressing cells as indicated by hemoglobin levels was significantly lower than that in Matrigel plugs containing the respective control cells. Blood vessel counts in paraffin sections of the Matrigel plugs containing sRIII-expressing cells were also significantly lower than those in paraffin sections of the Matrigel plugs containing control cells. Treatment of human endothelial cells with a recombinant sRIII significantly inhibited their ability to form a capillary web structure on Matrigel. These results for the first time indicate that the sRIII-induced tumor suppression appears to be in part due to the inhibition of angiogenesis.

Signal transduction pathways in androgen-dependent and -independent prostate cancer cell proliferation.

In a previous report, we showed that increased activation of Akt, a downstream effector of phosphoinositide 3-kinase (PI3K) together with decreased activation of extracellular-signal-regulated kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family, predicted poor clinical outcome in prostate cancer (Kreisberg et al. 2004 Cancer Research 64 5232-5236). We now show that Akt activation, but not ERK activation, is correlated with proliferation in human prostate tumors as estimated by the expression of the cell proliferation antigen Ki67. We verified these results in vitro, using the androgen-dependent prostate cancer cell line LNCaP and its androgen-independent clone C4-2 as models of prostate cancer of good and poor clinical outcome, respectively. C4-2 cells expressed higher Akt activation, lower ERK activation and increased proliferation compared with LNCaP cells, similar to cases of poor clinical outcome. The PI3K inhibitor LY294002, but not the MAPK/ERK kinase inhibitor PD98059, induced growth arrest in both cell lines. Transient transfection with constitutively active Akt increased proliferation while dominant negative Akt decreased it, thus showing that Akt plays an important role in prostate cancer proliferation. Akt regulates the expression and activation of the androgen receptor. Androgen receptor inhibition with Casodex induced growth arrest in LNCaP cells, but not in C4-2 cells. Another PI3K downstream effector, p70 S6 kinase, requires prior phosphorylation by mammalian target of rapamycin (mTOR) for complete activation. Activation of p70 S6 kinase was higher in C4-2 compared with LNCaP cells. Rapamycin, an mTOR inhibitor, had a growth-inhibitory effect in C4-2 cells, but not in LNCaP cells. Our data suggest a shift from a Casodex-sensitive proliferation pathway in LNCaP cells to a rapamycin-sensitive pathway in C4-2 cells.

Pharmacodynamic evaluation of the epidermal growth factor receptor inhibitor OSI-774 in human epidermis of cancer patients.

BACKGROUND: OSI-774 is an inhibitor of the epidermal growth factor receptor tyrosine kinase (EGFR-TK) currently in clinical development. In preclinical models, the antitumor activity of OSI-774 was directly related to its ability to inhibit the EGFR-TK. On the basis of these data, we hypothesized that inhibition of the EGFR-TK will be required for this agent to be effective in the clinic. This study evaluated the pharmacodynamic effects of OSI-774 in normal skin tissues collected from patients treated with the agent in a Phase I study. METHODS: Patients with advanced cancer who were treated in a Phase I study of OSI-774 underwent a biopsy of normal skin epidermis at baseline and after the last dose of drug in the first course of treatment. The expression and activation of the EGFR, downstream signaling extracytoplasmatic-regulated kinase (Erk), and cell cycle regulator p27 were determined in paraffin-embedded skin tissues using an immunohistochemical method (IHC). The IHC data were analyzed using both a semiquantitative scoring system and an automatic absorbance quantitative IHC method. The number of cells with nuclear staining of p27 per 500 cells was determined. Plasma samples were collected to quantitate OSI-774 plasma concentrations. RESULTS: A total of 56 skin specimens was collected from 28 patients treated with OSI-774 at doses ranging from 25 to 200 mg/day. There was a significant decrease in phospho-EGFR (Tyr 1173) expression as determined semiquantitatively with OSI-774 treatment [2.75 +/- 0.51 (mean +/- SD) pretreatment versus 2.36 +/- 0.76 after treatment, pair comparison P = 0.01]. The quantitative ratio [(phopho-EGFR/EGFR) x 100] of phospho-EGFR (Tyr1173) decreased from 64.16 +/- 36.58 pretreatment to 48.87 +/- 35.37 post-treatment (pair comparison, P = 0.02). No significant differences were observed in phospho-Erk (Thr202/Tyr204) expression. The mean number of cells with nuclear staining for p27 increased from 185 +/- 101 (mean +/- SD) pretreatment to 253 +/- 111 post-treatment (pair comparison P = 0.02). A total of 12 (42.8%), 7 (25%), and 14 (50%) patients had >25% variation in the ratio of phospho-EGFR (Tyr1173), phospho-Erk (Thr202/Tyr204), and p27 expression, respectively. Only changes in p27 expression were related to the administered dose of OSI-774. CONCLUSIONS: OSI-774 exerted pharmacodynamic effects in skin tissues of 30-50% of patients treated with the agent. Up-regulation of p27, which is a downstream effect of EGFR inhibition, was dose related. Although there was a significant decrement in phospho-EGFR (Tyr1173), it was not related to the administered dose of OSI-774. On the basis of these findings and the relatively simple and reliable method to measure p27 expression, this biomarker appears to be the most promising and is being evaluated in Phase II studies as a predictor of clinical outcome.

Immunohistochemical demonstration of phospho-Akt in high Gleason grade prostate cancer.

PURPOSE: Whereas the early stage of prostate cancer is marked by excessive proliferation, in advanced stages of the disease, a decreased apoptotic death rate (increased cell survival) also contributes to net tumor growth. Altered regulation of the mitogen-activated protein kinase (MAPK)-regulated cell proliferation and Akt-regulated cell survival pathways are suspected causes. In this study, we wanted to determine: (a) whether the degree of Akt activation can be assessed by immunohistochemical staining of paraffin- embedded human prostate cancer biopsies with an antibody to phospho-Akt (Ser473); and (b) whether phospho-MAPK/Erk1/2 and phospho-Akt expression are altered in prostate cancer. EXPERIMENTAL DESIGN: To examine the activation status of MAPK/Erk1/2 and Akt, archival paraffin-embedded sections from 74 cases of resected prostate cancer were immunostained with antibodies to phospho-MAPK/Erk1/2 (Thr202/ Tyr204) and phospho-Akt (Ser473). RESULTS: The staining intensity for phospho-Akt was significantly greater in Gleason grades 8-10 (92% of such cases staining strongly) compared with prostatic intraepithelial neoplasia and all other grades of prostate cancer (only 10% of these cases staining strongly; P < or = 0.001). The staining intensity for phospho-MAPK/Erk, on the other hand, was significantly greater for normal, hyperplastic, and prostatic intraepithelial neoplasia lesions but declined with disease progression, reaching its lowest level of expression in high Gleason grades 8-10 (P < 0.0001). CONCLUSION: The activation state of the cell survival protein Akt can be analyzed in human prostate cancer by immunohistochemical staining of paraffin-embedded tissue with a phospho-specific Akt (Ser473) antibody. Advanced disease is accompanied by activation of Akt and inactivation of Erk.

A Phase I pharmacokinetic and biological correlative study of oblimersen sodium (genasense, g3139), an antisense oligonucleotide to the bcl-2 mRNA, and of docetaxel in patients with hormone-refractory prostate cancer.

PURPOSE: To assess the feasibility of administering oblimersen sodium, a phosphorothioate antisense oligonucleotide directed to the Bcl-2 mRNA, with docetaxel to patients with hormone-refractory prostate cancer; to characterize the pertinent pharmacokinetic parameters, Bcl-2 protein inhibition in peripheral blood mononuclear cell(s) (PBMC) and tumor; and to seek preliminary evidence of antitumor activity. EXPERIMENTAL DESIGN: Patients were treated with increasing doses of oblimersen sodium administered by continuous i.v. infusion on days 1 to 6 and docetaxel administered i.v. over 1 h on day 6 every 3 weeks. Plasma was sampled to characterize the pharmacokinetic parameters of both oblimersen and docetaxel, and Bcl-2 protein expression was measured from paired collections of PBMCs pretreatment and post-treatment. RESULTS: Twenty patients received 124 courses of the oblimersen and docetaxel combination at doses ranging from 5 to 7 mg/kg/day oblimersen and 60 to 100 mg/m(2) docetaxel. The rate of severe fatigue accompanied by severe neutropenia was unacceptably high at doses exceeding 7 mg/kg/day oblimersen and 75 mg/m(2) docetaxel. Nausea, vomiting, and fever were common, but rarely severe. Oblimersen mean steady-state concentrations were 3.44 +/- 1.31 and 5.32 +/- 2.34 at the 5- and 7-mg/kg dose levels, respectively. Prostate-specific antigen responses were observed in 7 of 12 taxane-naïve patients, but in taxane-refractory patients no responses were observed. Preliminary evaluation of Bcl-2 expression in diagnostic tumor specimens was not predictive of response to this therapy. CONCLUSIONS: The recommended Phase II doses for oblimersen and docetaxel on this schedule are 7 mg/kg/day continuous i.v. infusion days 1 to 6, and 75 mg/m(2) i.v. day 6, respectively, once every 3 weeks. The absence of severe toxicities at this recommended dose, evidence of Bcl-2 protein inhibition in PBMC and tumor tissue, and encouraging antitumor activity in HPRC patients warrant further clinical evaluation of this combination.

Akt in prostate cancer: possible role in androgen-independence.

Akt, a downstream effector of phosphatidylinositol 3-kinase (PI3K), has often been implicated in prostate cancer. Studies in prostate tumor cell lines revealed that Akt activation is probably important for the progression of prostate cancer to an androgen-independent state. Investigations of human prostate cancer tissues show that although there is neither Akt gene amplification nor enhanced protein expression in prostate cancer compared to normal tissue, poorly differentiated tumors exhibit increased expression of a phosphorylated (activated) form of Akt compared to normal tissue, prostatic intraepithelial neoplasia (PIN) or well-differentiated prostate cancer. Akt phosphorylation is accompanied by the inactivation of ERK, a member of the mitogen activated protein kinase (MAPK) family. In this article, we postulate that Akt promotes androgen-independent survival of prostate tumor cells by modulating the expression and activation of the androgen receptor (AR).