Combining tumor deposits with the number of lymph node metastases to improve the prognostic accuracy in stage III colon cancer: a post hoc analysis of the CALGB/SWOG 80702 phase III study (Alliance)☆.

BACKGROUND: In colon cancer, tumor deposits (TD) are considered in assigning prognosis and staging only in the absence of lymph node metastasis (i.e. stage III pN1c tumors). We aimed to evaluate the prognostic value of the presence and the number of TD in patients with stage III, node-positive colon cancer. PATIENTS AND METHODS: All participants from the CALGB/SWOG 80702 phase III trial were included in this post hoc analysis. Pathology reports were reviewed for the presence and the number of TD, lymphovascular and perineural invasion. Associations with disease-free survival (DFS) and overall survival (OS) were evaluated by multivariable Cox models adjusting for sex, treatment arm, T-stage, N-stage, lymphovascular invasion, perineural invasion and lymph node ratio. RESULTS: Overall, 2028 patients were included with 524 (26%) TD-positive and 1504 (74%) TD-negative tumors. Of the TD-positive patients, 80 (15.4%) were node negative (i.e. pN1c), 239 (46.1%) were pN1a/b (<4 positive lymph nodes) and 200 (38.5%) were pN2 (≥4 positive lymph nodes). The presence of TD was associated with poorer DFS [adjusted hazard ratio (aHR) = 1.63, 95% CI 1.33-1.98] and OS (aHR = 1.59, 95% CI 1.24-2.04). The negative effect of TD was observed for both pN1a/b and pN2 groups. Among TD-positive patients, the number of TD had a linear negative effect on DFS and OS. Combining TD and the number of lymph node metastases, 104 of 1470 (7.1%) pN1 patients were re-staged as pN2, with worse outcomes than patients confirmed as pN1 (3-year DFS rate: 65.4% versus 80.5%, P = 0.0003; 5-year OS rate: 87.9% versus 69.1%, P = <0.0001). DFS was not different between patients re-staged as pN2 and those initially staged as pN2 (3-year DFS rate: 65.4% versus 62.3%, P = 0.4895). CONCLUSION: Combining the number of TD and the number of lymph node metastases improved the prognostication accuracy of tumor-node-metastasis (TNM) staging.

Enhanced recovery after surgery pathway in patients with soft tissue sarcoma.

BACKGROUND: Patients undergoing surgery for soft tissue sarcoma have high morbidity rates, particularly after preoperative radiation therapy (RT). An enhanced recovery after surgery (ERAS) programme may improve perioperative outcomes in abdominal surgery. This study reported outcomes of an ERAS programme tailored to patients with soft tissue sarcoma. METHODS: A prospective ERAS protocol was implemented in 2015 at a high-volume sarcoma centre. Patients treated within the ERAS programme from 2015 to 2018 were case-matched retrospectively with patients treated between 2012 and 2018 without use of the protocol, matched by surgical site, surgeon, sarcoma histology and preoperative RT treatment. Postoperative outcomes, specifically wound complications and duration of hospital stay, were reported. RESULTS: In total, 234 patients treated within the ERAS programme were matched with 237 who were not. The ERAS group had lower wound dehiscence rates overall (2 of 234 (0·9 per cent) versus 31 of 237 (13·1 per cent); P < 0·001), after preoperative RT (0 of 41 versus 11 of 51; P = 0·004) and after extremity sarcoma surgery (0 of 54 versus 6 of 56; P = 0·040) compared with the non-ERAS group. Rates of postoperative ileus or obstruction were lower in the ERAS group (21 of 234 (9·9 per cent) versus 40 of 237 (16·9 per cent); P = 0·016) and in those with retroperitoneal sarcoma (4 of 36 versus 15 of 36; P = 0·007). Duration of hospital stay was shorter in the ERAS group (median 5 (range 0-36) versus 6 (0-67) days; P = 0·003). CONCLUSION: Treatment within an ERAS protocol for patients with soft tissue sarcoma was associated with lower morbidity and shorter hospital stay.

ANTECEDENTES: Los pacientes sometidos a cirugía por sarcoma de tejido blando (soft tissue sarcoma, STS) tienen altas tasas de morbilidad, particularmente después de la radioterapia preoperatoria (RT). El programa de recuperación intensificada después de la cirugía (enhanced recovery after surgery, ERAS) puede mejorar los resultados perioperatorios en la cirugía abdominal. Este estudio analizó los resultados de un programa ERAS diseñado para pacientes con STS. MÉTODOS: Se implementó un protocolo prospectivo ERAS en el año 2015 en un centro de alto volumen de sarcomas. Los pacientes en ERAS desde 2015 hasta 2018 fueron emparejados retrospectivamente con pacientes sin ERAS desde 2012 hasta 2018, según la localización quirúrgica, el cirujano, la histología del sarcoma y el tratamiento con RT preoperatoria. Se analizaron los resultados postoperatorios, específicamente las complicaciones de la herida y la duración de la estancia hospitalaria (length of stay, LOS). RESULTADOS: En total, 234 pacientes tratados con ERAS se compararon con 237 pacientes no tratados con ERAS. Los pacientes con ERAS tuvieron tasas globales más bajas de dehiscencia de la herida (2 (0,9%) versus 31 (13,1%), P < 0,001)), después de la RT preoperatoria (0 versus 11 (21,6%), P = 0,004)), y después de la cirugía de STS de extremidades (0 versus 6 (0,7%), P = 0,04)) en comparación con los pacientes no ERAS. Las tasas de íleo u obstrucción postoperatorias fueron más bajas en el grupo ERAS (21 (9,9%) versus 40 (16,9%), P = 0,02)) y en aquellos pacientes con sarcoma retroperitoneal (4 (11,1%) versus 15 (41,7%), P = 0,007)). La mediana (rango) de la LOS fue más corta en los pacientes con ERAS que fue de 5 (0-36) días que en los pacientes sin ERAS que fue de 6 (0-67) días (P = 0,003). CONCLUSIÓN: ERAS para pacientes con STS se asoció con una menor morbilidad y una estancia hospitalaria más corta.

Prediction of morbidity following cytoreductive surgery for metastatic gastrointestinal stromal tumour in patients on tyrosine kinase inhibitor therapy.

BACKGROUND: Although cytoreductive surgery has been shown to be beneficial in carefully selected patients with metastatic gastrointestinal stromal tumours (GISTs) treated with tyrosine kinase inhibitors (TKIs), factors predictive of postoperative morbidity have not been investigated previously. METHODS: A surgical complexity score for GIST metastasectomy (GM-SCS) composed of patient-related and surgical factors was assigned retrospectively to patients with metastatic GIST treated with TKI therapy and surgery at two institutions between 2002 and 2014. The ability of clinicopathological factors and GM-SCS to predict postoperative morbidity was assessed by means of a multivariable logistic regression model. Postoperative complications were categorized using the Clavien-Dindo classification. RESULTS: Some 400 operations on 323 patients with metastatic GIST on TKIs were included. Complications were observed following 110 operations (27·5 per cent) including 70 major complications (grade III-V) (17·5 per cent of 400 operations). Patients were divided into low (5 points or less; 100 patients, 25·0 per cent), intermediate (6-9 points; 191, 47·8 per cent) and high (at least 10 points; 109, 27·3 per cent) complexity scoring groups based on the GM-SCS. An intermediate (odds ratio (OR) 2·88; P = 0·008) and high (OR 5·40; P < 0·001) GM-SCS were independent predictors of overall complications, whereas only a high GM-SCS was independently predictive of a major complication (OR 3·65; P = 0·018). Metastatic mitotic index was also an independent predictor of overall complications (OR 2·55; P = 0·047). GM-SCS did not predict progression-free or overall survival. CONCLUSION: A gastrointestinal stromal tumour metastastectomy surgical complexity score can predict morbidity, which may help in preoperative risk stratification and optimal treatment planning.

Predicted vitamin D status and colon cancer recurrence and mortality in CALGB 89803 (Alliance).

BACKGROUND: Observational studies suggest that higher levels of 25-hydroxyvitamin D3 (25(OH)D) are associated with a reduced risk of colorectal cancer and improved survival of colorectal cancer patients. However, the influence of vitamin D status on cancer recurrence and survival of patients with stage III colon cancer is unknown. PATIENTS AND METHODS: We prospectively examined the influence of post-diagnosis predicted plasma 25(OH)D on outcome among 1016 patients with stage III colon cancer who were enrolled in a National Cancer Institute-sponsored adjuvant therapy trial (CALGB 89803). Predicted 25(OH)D scores were computed using validated regression models. We examined the influence of predicted 25(OH)D scores on cancer recurrence and mortality (disease-free survival; DFS) using Cox proportional hazards. RESULTS: Patients in the highest quintile of predicted 25(OH)D score had an adjusted hazard ratio (HR) for colon cancer recurrence or mortality (DFS) of 0.62 (95% confidence interval [CI], 0.44-0.86), compared with those in the lowest quintile (Ptrend = 0.005). Higher predicted 25(OH)D score was also associated with a significant improvement in recurrence-free survival and overall survival (Ptrend = 0.01 and 0.0004, respectively). The benefit associated with higher predicted 25(OH)D score appeared consistent across predictors of cancer outcome and strata of molecular tumor characteristics, including microsatellite instability and KRAS, BRAF, PIK3CA, and TP53 mutation status. CONCLUSION: Higher predicted 25(OH)D levels after a diagnosis of stage III colon cancer may be associated with decreased recurrence and improved survival. Clinical trials assessing the benefit of vitamin D supplementation in the adjuvant setting are warranted. CLINICALTRIALS.GOV IDENTIFIER: NCT00003835.

TERC polymorphisms are associated both with susceptibility to colorectal cancer and with longer telomeres.

BACKGROUND AND AIMS: Shorter telomeres have been associated with increased risk of malignancy, including colorectal cancer (CRC). Telomere length is heritable and may be an intermediate phenotype linked to genetic susceptibility to CRC. METHODS: In a large sample, the study investigated whether candidate single nucleotide polymorphisms (SNP) in 'telomere biology' genes were associated with telomere length in leucocytes. SNP associated with an increased risk of CRC were searched for separately. RESULTS: Carriers of the common allele at SNP rs10936599, near the telomerase RNA component (TERC) locus, had significantly longer telomeres. It was independently found that the same rs10936599 allele was associated with increased risk of both CRC and colorectal adenomas. Neither telomere length nor CRC risk was associated with variation near telomerase reverse transcriptase or other telomere biology genes. In silico analysis showed that SNP rs2293607 was strongly correlated with rs10936599, mapped within TERC transcripts, had a predicted effect on messenger RNA folding and lay at a reported transcription factor binding site. TERC mRNA were expressed, differing only at the alleles of rs2293607, in CRC cell line HCT116. The long-telomere/CRC-risk allele was associated with higher levels of TERC mRNA and the formation of longer telomeres. CONCLUSIONS: Common genetic variation at TERC is associated with both longer telomeres and an increased risk of CRC, a potential mechanism being reduced levels of cell senescence or death. This finding is somewhat paradoxical, given retrospective studies reporting that CRC cases have shorter telomeres than controls. One possibility is that that association actually results from poorer survival in patients with longer telomeres.

Evidence for the selective association of a subpopulation of GPIIb-IIIa with the actin cytoskeletons of thrombin-activated platelets.

Activation of blood platelets triggers a series of responses leading to the formation and retraction of blood clots. Among these responses is the establishment of integrin-mediated transmembrane connections between extracellular matrix components and the actin cytoskeleton of the platelet. Here we report that a specific subpopulation of the major platelet integrin, glycoprotein IIb-IIIa (GPIIb-IIIa) (also referred to as alpha IIb beta 3 integrin), becomes incorporated into the detergent-insoluble actin cytoskeleton of platelets during the platelet activation response. The cytoskeletal association of GPIIb-IIIa is independent of platelet aggregation and fibrin sedimentation and is sensitive to cytochalasin D treatment. As determined by Western immunoblot analysis, approximately 22% of the total cellular GPIIb-IIIa becomes associated with the actin cytoskeleton upon thrombin activation in a manner that is independent of the detection of talin, alpha-actinin, or vinculin in the complex. We found that the cytoskeleton-associated GPIIb-IIIa is derived from an intracellular source since it is not available for lactoperoxidase-catalyzed radioiodination before platelet activation. Two intracellular sources of GPIIb-IIIa are present in resting platelets: GPIIb-IIIa associated with the alpha-granule secretory compartment as well as surface-inaccessible domains of the surface-connected canalicular system. Interestingly, alpha-granule secretion, which occurs in thrombin-activated platelets and results in the translocation of intracellular GPIIb-IIIa to the plasma membrane, appears to be required for the cytoskeleton incorporation of GPIIb-IIIa that we observe. Collectively, our data provide evidence that a subpopulation of GPIIb-IIIa derived from an intracellular source is selectively linked to the actin cytoskeleton of platelets upon thrombin activation in the absence of platelet aggregation.

Activation-dependent redistribution of the adhesion plaque protein, talin, in intact human platelets.

Talin is a high molecular weight protein localized at adhesion plaques in fibroblasts. It binds vinculin and integrin and appears to participate in generating a transmembrane connection between the extracellular matrix and the cytoskeleton. We have recently shown that talin is an abundant protein in platelets, cells highly specialized for regulated adhesion. Although talin constitutes greater than 3% of the total protein in intact human platelets, its location within the cells had not been defined. In the work reported here, we have investigated the distribution of talin in resting and activated human platelets by immunofluorescence and immunoelectron microscopy. We have found that talin undergoes an activation-dependent change in its subcellular location. In resting platelets, which are nonadhesive, talin is uniformly distributed throughout the cytoplasm. In contrast, in thrombin- and glass-activated, substratum-adherent platelets, talin is concentrated at the cytoplasmic face of the plasma membrane. This dramatic, regulated redistribution of talin raises the possibility that talin plays a role in the controlled development of platelet adhesion.

Insulin resistance in vascular endothelial cells promotes intestinal tumour formation.

The risk of several cancers, including colorectal cancer, is increased in patients with obesity and type 2 diabetes, conditions characterised by hyperinsulinaemia and insulin resistance. Because hyperinsulinaemia itself is an independent risk factor for cancer development, we examined tissue-specific insulin action in intestinal tumour formation. In vitro, insulin increased proliferation of intestinal tumour epithelial cells by almost two-fold in primary culture of tumour cells from ApcMin/+ mice. Surprisingly, targeted deletion of insulin receptors in intestinal epithelial cells in ApcMin/+ mice did not change intestinal tumour number or size distribution on either a low or high-fat diet. We therefore asked whether cells in the tumour stroma might explain the association between tumour formation and insulin resistance. To this end, we generated ApcMin/+ mice with loss of insulin receptors in vascular endothelial cells. Strikingly, these mice had 42% more intestinal tumours than controls, no change in tumour angiogenesis, but increased expression of vascular cell adhesion molecule-1 (VCAM-1) in primary culture of tumour endothelial cells. Insulin decreased VCAM-1 expression and leukocyte adhesion in quiescent tumour endothelial cells with intact insulin receptors and partly prevented increases in VCAM-1 and leukocyte adhesion after treatment with tumour necrosis factor-α. Knockout of insulin receptors in endothelial cells also increased leukocyte adhesion in mesenteric venules and increased the frequency of neutrophils in tumours. We conclude that although insulin is mitogenic for intestinal tumour cells in vitro, impaired insulin action in the tumour microenvironment may be more important in conditions where hyperinsulinaemia is secondary to insulin resistance. Insulin resistance in tumour endothelial cells produces an activated, proinflammatory state that promotes tumorigenesis. Improvement of endothelial dysfunction may reduce colorectal cancer risk in patients with obesity and type 2 diabetes.

(+)-Catechin inhibits intestinal tumor formation and suppresses focal adhesion kinase activation in the min/+ mouse.

Colorectal cancer is sensitive to dietary influences. Epidemiological data linking high intake of fruits and vegetables to decreased cancer risk have prompted the search for specific plant constituents implicated in tumor prevention. This task is difficult because of the complex chemical composition of plant foods and the multifactorial nature of carcinogenesis. Researchers are aided in this effort by the C57BL/6J-Min/+ (Min/+) mouse, an animal bearing a germline defect in Apc that is similar to the initiating genetic event in the majority of human colorectal cancers. In this study, we treated Min/+ mice with (+)-catechin, a phenolic antioxidant abundant in certain fruits. Administration of (+)-catechin in an AIN-76A diet at doses of 0.1 and 1% decreased the intestinal tumor number by 75 and 71%, respectively. Mechanistic studies linked this effect to (+)-catechin-induced changes in integrin-mediated intestinal cell-survival signaling, including structural alteration of the actin cytoskeleton and decreased focal adhesion kinase (FAK) tyrosine phosphorylation. Immunoblot analysis of small intestine scrapings from Min/+ mice and Apc+/+ wild-type C57BL/6J littermates together with excised Min/+ adenomas showed increased expression of phosphorylated FAK in the macroscopically normal enterocytes of untreated Min/+ mice and adenomas. Confirming the relevance of this signaling pathway, treatment of Min/+ mice with (+)-catechin reduced the expression of phosphorylated FAK to a level similar to the wild-type littermate controls. Thus, the natural abundance and favorable bioavailability of (+)-catechin make it a promising addition to the list of potential colorectal cancer chemopreventive agents.

Apc gene mutation is associated with a dominant-negative effect upon intestinal cell migration.

Apc-associated intestinal tumor formation appears to require functional loss of both Apc alleles. Apc has, therefore, been classified as a tumor suppressor gene. Loss of APC protein function results in increased intracellular beta-catenin, a molecule important to both cell-cell adhesion and regulation of cellular growth. In mice bearing a germ-line Apc mutation, we found that enterocyte beta-catenin expression was also increased in histologically normal intestinal mucosa. Enterocyte crypt-villus migration was decreased by 25%, and treatment of Min/+ animals with sulindac sulfide normalized both beta-catenin expression and enterocyte migration. Our data suggest that alterations in enterocyte migration occur in cells bearing a single mutant Apc allele, and that sulindac sulfide may normalize enterocyte growth in these cells.

Genotype-phenotype correlation in murine Apc mutation: differences in enterocyte migration and response to sulindac.

The adenomatous polyposis coli (APC) gene product mediates coordinated cell growth in the intestinal mucosa. In humans, germ-line mutations of APC are associated with colorectal carcinogenesis, a process that varies in severity depending on the length of the protein resulting from the mutant allele. In a previous study of the C57BL/6J-Min/+ (Min/+) mouse, we found that the protein fragment resulting from truncation at codon 850 of murine Apc was associated with changes in enterocyte migration, proliferation, apoptosis, and beta-catenin expression. This effect was reversed upon treatment of Min/+ mice with the chemopreventive drug sulindac sulfide. In this study, we measured enterocyte migration in the Apc1638N mouse, an animal with an Apc mutation that yields no detectable APC protein. We found no difference in enterocyte migration, proliferation, apoptosis, or beta-catenin levels in the Apc1638N mouse when compared to wild-type littermates bearing two normal Apc alleles. Furthermore, administration of sulindac sulfide to Apc1638N mice did not alter enterocyte migration. These observations suggest that a dominant negative effect altering cell migration is exerted by the truncated APC protein present in the Min/+ mouse. These data also suggest that the effectiveness of chemopreventive agents in preventing Apc-related tumor formation may depend on which type of mutation is present.

Reciprocal expression of ERalpha and ERbeta is associated with estrogen-mediated modulation of intestinal tumorigenesis.

Menopausal hormone replacement therapy has been widely used to alleviate the symptoms of menopause and to decrease the detrimental effects of ovarian hormone loss on bone density and cardiovascular health. Multiple studies of colorectal cancer epidemiology also support a role for hormone replacement therapy in prevention of colorectal cancer. We studied the effect of ovariectomy and estrogen replacement on tumor formation in C57BL/6J-Min/+ (Min/+) mice, animals that bear a germline mutation in murine Apc. These mice develop multiple intestinal tumors that show loss of wild-type Apc protein. After ovariectomy, intestinal adenomas in Min/+ mice increased by 77% (P = 0.0004). Ovariectomized Min/+ mice that were treated with a replacement dose of 17beta-estradiol had the same number of tumors as Min/+ mice that were neither castrated nor treated with estrogen replacement (P = 0.85). Examination of estrogen receptor (ER) levels in intestinal tissue by immunoblot showed changes in relative expression levels of ERalpha and ERbeta, with highest ERalpha and lowest ERbeta expression in the normal-appearing intestine of Min/+ mice, and lowest ERalpha and highest ERbeta expression in the enterocytes of animals that received 17beta-estradiol. These results suggest that endogenous estrogens protect against Apc-associated tumor formation and that tumor prevention by 17beta-estradiol is associated with an increase in ERbeta and a decrease in ERalpha expression in the target tissue.

Cyclooxygenase-2 overexpression and tumor formation are blocked by sulindac in a murine model of familial adenomatous polyposis.

Inducible cyclooxygenase (Cox-2), also known as prostaglandin H synthase 2 (PGH-2) is a key enzyme in the formation of prostaglandins and thromboxanes. Cox-2 is the product of an immediate-early gene that is expressed in response to growth factors, tumor promoters, or cytokines. Overexpression of Cox-2 is associated with both human colon cancers and suppression of apoptosis in cultured epithelia] cells, an activity that is reversed by the nonsteroidal anti-inflammatory drug, sulindac sulfide. To address the relationship between Cox-2, apoptosis, and tumor development in vivo, we studied C57BL/6J-Min/+(Min) mice, a strain containing a fully penetrant dominant mutation in the Apc gene, leading to the development of gastrointestinal adenomas by 110 days of age. Min mice were fed AIN-76A chow diet and given sulindac (0.5 +/- 0.1 mg/day) in drinking water. Control Min mice and homozygous C57BL/6J-+/+ normal littermates lacking the Apc mutation (+/+) were fed AIN-76A diet and given tap water to drink. At 110 days of age, all mice were sacrificed, and their intestinal tracts were examined. Control Min mice had 11.9 +/- 7.8 tumors per mouse compared to 0.1 +/- 0.1 tumors for sulindac-treated Min mice. As expected, +/+ littermates had no macroscopic tumors. Examination of histologically normal-appearing small bowel from Min animals revealed increased amounts of Cox-2 and prostaglandin E(2) compared to +/+ littermates. Using two different in situ techniques, terminal transferase-mediated dUTP nick end labeling and a direct immunoperoxidase method, Min animals also demonstrated a 27-47% decrease in enterocyte apoptosis compared to +/+ animals. Treatment with sulindac not only inhibited tumor formation but decreased small bowel Cox-2 and prostaglandin E(2) to baseline and restored normal levels of apoptosis. These data suggest that overexpression of Cox-2 is associated with tumorigenesis in the gastrointestinal epithelium, and that both are inhibited by sulindac administration.

Colon cancer chemopreventive drugs modulate integrin-mediated signaling pathways.

Epidemiological studies of colorectal cancer incidence suggest that the development of this disease can be modulated by dietary factors. Among the micronutrients showing significant efficacy in tumor prevention are polyphenolic antioxidants found in fruits and vegetables. Epidemiological studies also indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the incidence of colorectal cancer. Integrin-mediated cell-matrix contact provides critical signaling that regulates cellular proliferation, migration, and apoptosis. A signaling mediator for this system is focal adhesion kinase (FAK). Thus far, FAK has not been identified as a target for the inhibitory action of any chemopreventive drug in vivo or in vitro. However, the loss of integrin-mediated cell-matrix contact can induce apoptosis (anoikis), and effective chemopreventive agents typically increase the rate of enterocyte apoptosis. Therefore, we asked whether the NSAID, sulindac sulfide, and the phenolic antioxidant, caffeic acid phenethyl ester (CAPE), affected FAK expression or tyrosine phosphorylation in human colon carcinoma cells. We show that subapoptotic doses of both sulindac sulfide and CAPE caused a rearrangement of the actin cytoskeleton and consequently the loss of focal adhesion plaques. These drugs also reduced the tyrosine phosphorylation of FAK and an associated factor, p130Cas. Steady-state levels of these proteins, together with other relevant signaling molecules, remained unchanged after treatments. Finally, we show that both CAPE and sulindac reduced cell invasion, a functional assay for the inhibition of signaling downstream of FAK. These data strongly suggest that chemopreventive drugs can regulate FAK activity. In conclusion, these novel studies add modulation of integrin-mediated signaling to the spectrum of activity of NSAIDs and plant phenolics.

Evidence that rapamycin inhibits interleukin-12-induced proliferation of activated T lymphocytes.

Interleukin 12 is a heterodimeric cytokine involved in the regulation of natural killer cell and T lymphocyte responses. In previous studies, we found that IL-12 induces proliferation of T cells only after co-stimulation with lectin, alloantigen, or anti-CD3 antibody. The IL-2-mediated proliferation of long-term T cell lines generated in this fashion is typically insensitive to the immunosuppressive agent, cyclosporine but sensitive to rapamycin. In this study, we examined the effect of cyclosporine and rapamycin on T cells responsive to IL-12. For long-term cultured T cell lines stimulated with phytohemagglutinin, alloantigen, or solid-phase anti-CD3 antibody, rapamycin blocked IL-12-induced proliferation to background levels. Culture in cyclosporine produced minimal inhibition of IL-12-induced T cell proliferation. Freshly isolated CD3+ cells did not proliferate in response to IL-12, nor did culture of these cells in IL-12 lead to upregulation of IL-2 receptor. These data suggest that the effect of IL-12, an important growth regulator for activated T lymphocytes, may involve late cellular activation events.

2-Methoxyestradiol induces p53-associated apoptosis of colorectal cancer cells.

Menopausal estrogen replacement therapy is thought to be responsible for the recent decline in colorectal cancer (CRC) incidence among women. In the C57BL/6J-Min/+ mouse, an animal model of CRC, 17beta-estradiol (E(2)) prevents tumor formation in ovariectomized females. We examined human CRC intestinal cell lines to determine whether particular E(2) metabolites produced anti-tumor effects. Treatment of CRC cells with 2-methoxyestradiol (2-MeOE(2)) increased expression of p53 and p21(WAF1/CIP1) proteins and induced apoptosis, but did not produce changes in expression of estrogen receptor (ER)alpha or ERbeta. The finding that 2-MeOE(2) induces p53-mediated colon cell apoptosis in vitro supports a role for 2-MeOE(2) as an endogenous mediator of intestinal tumor suppression.

APC and intestinal carcinogenesis. Insights from animal models.

The APC protein is a crucial regulator of intestinal cell growth, and mutations in the APC gene are a common initial event in the process of human colorectal carcinogenesis. Animals bearing germline mutations in Apc are therefore important models for human colorectal cancer. These animals have been used both to understand the biology of human colorectal cancer and to screen for agents able to prevent malignant transformation of susceptible intestinal cells.

Approaches to immunotherapy of cancer: characterization of lymphokines as second signals for cytotoxic T-cell generation.

Lymphokines, the soluble molecules produced by cells of the immune system, regulate cell-cell interactions and, consequently, the functional status of the immune system. Altering immunoregulatory pathways with lymphokines in vivo may provide a mechanism for controlling a variety of immunologic disorders. Although normally produced in vivo in very small quantities, the widespread availability of recombinant lymphokines has made it possible to study the molecular signals involved in production of lymphocyte effectors with activity against tumor. For example, interleukin-2-based cancer immunotherapy programs have, in certain clinical situations, suggested that immunologic intervention can influence the regression of metastatic cancer. Ultimately the successful application of these biologic agents requires an understanding of the interaction between the immune system and tumor on a molecular level. To induce a given biologic effect, it is necessary both to classify the required lymphokines and to identify the relevant effector cell populations. This review will examine the progress made in identifying the requirements for lymphokine-induced cytotoxic T-lymphocyte function.

Aspirin prevents tumors in a murine model of familial adenomatous polyposis.

BACKGROUND: Both human and murine studies suggest that anti-inflammatory drugs prevent intestinal neoplasia. The purpose of this study was to investigate the role of aspirin as a chemopreventive agent for colorectal cancer. METHODS: We administered aspirin to the Min/+ mouse, an animal with a germline mutation in Apc, a gene that is essential for normal epithelial cell growth and differentiation. Apc mutation increases cytoplasmic beta-catenin, a regulatory protein associated with the cytoskeleton. Min/+ mice develop multiple intestinal adenomas and exhibit altered cell growth in the preneoplastic intestinal epithelium. RESULTS: Aspirin decreased the rate of tumor formation in Min/+ mice by 44%. Aspirin also normalized enterocyte growth by increasing apoptosis and proliferation in the preneoplastic intestinal mucosa. Finally, aspirin produced a decrease in intracellular beta-catenin levels, suggesting that modulation of this protein is associated with tumor prevention. CONCLUSIONS: These data confirm a role for aspirin in suppression of Apc-associated intestinal carcinogenesis.