Modeling rectal cancer to advance neoadjuvant precision therapy.

Progress in rectal cancer therapy has been hindered by the lack of effective disease-specific preclinical models that account for the unique molecular profile and biology of rectal cancer. Thus, we developed complementary patient-derived xenograft (PDX) and subsequent in vitro tumor organoid (PDTO) platforms established from preneoadjuvant therapy rectal cancer specimens to advance personalized care for rectal cancer patients. Multiple endoscopic samples were obtained from 26 Stages 2 and 3 rectal cancer patients prior to receiving 5FU/RT and implanted subcutaneously into NSG mice to generate 15 subcutaneous PDXs. Second passaged xenografts demonstrated 100% correlation with the corresponding human cancer histology with maintained mutational profiles. Individual rectal cancer PDXs reproduced the 5FU/RT response observed in the corresponding human cancers. Similarly, rectal cancer PDTOs reproduced significant heterogeneity in cellular morphology and architecture. PDTO in vitro 5FU/RT treatment response replicated the clinical 5FU/RT neoadjuvant therapy pathologic response observed in the corresponding patient tumors (p < 0.05). The addition of cetuximab to the 5FU/RT regiment was significantly more sensitive in the rectal cancer PDX and PDTOs with wild-type KRAS compared to mutated KRAS (p < 0.05). Considering the close relationship between the patient's cancer and the corresponding PDX/PDTO, rectal cancer patient-derived research platforms represent powerful translational research resources as population-based tools for biomarker discovery and experimental therapy testing. In addition, our findings suggest that cetuximab may enhance RT effectiveness by improved patient selection based on mutational profile in addition to KRAS or by developing a protocol using PDTOs to identify sensitive patients.

Effect of metabolic syndrome and its components on recurrence and survival in colon cancer patients.

BACKGROUND: Although epidemiologic studies suggest that metabolic syndrome (MetS) increases the risk of colorectal cancer, its effect on cancer mortality remains controversial. METHODS: The authors used the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database (1998-2006) to conduct a retrospective cohort study of 36,079 patients with colon cancer to determine the independent effect of MetS and its components on overall survival (OS) and recurrence-free rates (RFRs). Data on MetS and its components were ascertained from Medicare claims. OS and RFRs in patients with and without MetS and its components were compared using multivariate Cox models. RESULTS: MetS had no apparent effect on OS or RFR. Both elevated glucose/diabetes mellitus (DM) and elevated hypertension were associated with worse OS (adjusted hazard ratio [aHR], 1.17 [95% confidence interval, 1.13-1.21] and 1.08 [95% confidence interval, 1.03-1.12], respectively) and worse RFRs (aHR, 1.25 [95% confidence interval, 1.16-1.34] and 1.22 [95% confidence interval, 1.12-1.33], respectively). In contrast, dyslipidemia was associated with improved survival (aHR, 0.77; 95% confidence interval, 0.75-0.80) and reduced recurrence (aHR, 0.71; 95% confidence interval, 0.66-0.75). These effects were consistent for both men and women and were more pronounced in patients with early stage disease. CONCLUSIONS: MetS had no apparent effect on colon cancer outcomes, probably because of the combined adverse effects of elevated glucose/DM and hypertension and the protective effect of dyslipidemia in patients with nonmetastatic disease. The authors concluded that patients who have early stage colon cancer with elevated glucose/DM and/or hypertension may benefit from more intensive surveillance and/or broader use of adjuvant therapy and that trials to define the benefits of low-fat diets, insulin-lowering agents, and statins on recurrence/survival in patients with nonmetastatic colon cancer are warranted.

Targeting of insulin-like growth factor-I receptor with a monoclonal antibody inhibits growth of hepatic metastases from human colon carcinoma in mice.

BACKGROUND: Colorectal carcinomas (CRC) express high levels of insulin-like growth factor-I/II (IGF-I/II) and the receptor (IGF-IR). We hypothesized that selective inhibition of IGF-IR would inhibit hepatic growth of human CRC in mice. METHODS: Human CRC cells were treated in vitro with anti-IGF-IR monoclonal antibody (MoAB) with and without oxaliplatin to assess cytotoxicity. The effect of anti-IGF-IR MoAB on IGF-I-induced vascular endothelial growth factor (VEGF) production in human CRC cells was assessed by Northern blot and ELISA. We injected human CRC cells intrahepatically in nude mice, and then administered anti-IGF-IR MoAB with and without oxaliplatin. We delayed treatment in one group until large hepatic tumors were present. We assessed tumors for apoptosis, proliferation, and angiogenesis. RESULTS: Anti-IGF-IR MoAB and oxaliplatin inhibited CRC cell growth in vitro and combination treatment was even more effective. IGF-I stimulation of CRC cells resulted in significant upregulation of VEGF and this was completely inhibited by pretreatment with anti-IGF-IR MoAB. Anti-IGF-IR MoAB significantly inhibited hepatic growth of tumors in mice. Anti-IGF-IR MoAB plus oxaliplatin led to a significantly greater inhibition of tumor growth. Anti-IGF-IR MoAB plus oxaliplatin was just as effective at inhibiting growth of larger, more advanced liver tumors. Anti-IGF-IR MoAB, alone and in combination with oxaliplatin, led to a significant increase in tumor cell apoptosis, and a significant inhibition of tumor cell proliferation and angiogenesis. CONCLUSIONS: These findings suggest that IGF-IR is a potential target for therapy in patients with advanced CRC.

Enhanced sensitivity to chemotherapy in esophageal cancer through inhibition of NF-kappaB.

BACKGROUND: Apoptosis induced by chemotherapeutic drugs is blocked by activation of nuclear factor-kappaB (NF-kappaB) in some cancer cell lines. Therefore, inhibition of NF-kappaB by adenoviral delivery of an IkappaBalpha super-repressor (Ad.IkappaBalpha-SR) should make esophageal cancer cells more sensitive to 5- fluorouracil (5-FU) and taxotere chemotherapy. MATERIALS AND METHODS: SEG1 and BIC1 human esophageal cancer cells were studied. Chemotherapy-induced NF-kappaB activation was assessed by luciferase reporter assay and by electrophoretic mobility shift assay (EMSA). Cell growth inhibition was assessed by cell proliferation assay. Apoptosis was determined by flow cytometry and caspase 3/7 assay. RESULTS: 5-FU and taxotere significantly induced NF-kappaB activation as measured by luciferase reporter assay (P < 0.005) and EMSA. In both cell lines, Ad.IkappaBalpha-SR enhanced apoptosis by caspase 3/7 assay as compared to chemotherapy alone. In SEG1 cells, pre-treatment with Ad.IkappaBalpha-SR followed by 5-FU (0.25 mm) or taxotere (0.01 ug/ml), led to an increased apoptosis of 183% and 55%, respectively (P < 0.005). Similarly, apoptosis in BIC1 cells was significantly increased by pre-treatment with Ad.IkappaBalpha followed by 5-FU (0.1 mm) or taxotere (0.01 ug/ml) (P < 0.005). Growth inhibition in both cell lines was also significantly increased by pre-treatment with Ad.IkappaBalpha followed by 5-FU (0.01 mm) or taxotere (0.001 ug/ml) (P < 0.0005). CONCLUSION: Treatment with 5-FU or taxotere induced NF-kappaB activation in human esophageal cancer cells. Inhibition of NF-kappaB by Ad.IkappaBalpha-SR increased their sensitivity to 5-FU and taxotere chemotherapy. Therefore, these results may provide the basis for novel clinical approaches using cytoxic therapy with NF-kappaB inhibition to improve outcome in patients with esophageal cancer.

Targeting of urokinase plasminogen activator receptor in human pancreatic carcinoma cells inhibits c-Met- and insulin-like growth factor-I receptor-mediated migration and invasion and orthotopic tumor growth in mice.

Pancreatic carcinomas express high levels of urokinase-type plasminogen activator (uPA) and its receptor (uPAR), both of which mediate cell migration and invasion. We investigated the hypotheses that (a) insulin-like growth factor-I (IGF-I)- and hepatocyte growth factor (HGF)-mediated migration and invasion of human pancreatic carcinoma cells require uPA and uPAR function and (b) inhibition of uPAR inhibits tumor growth, retroperitoneal invasion, and hepatic metastasis of human pancreatic carcinomas in mice. Using transwell assays, we investigated the effect of IGF-I and HGF on L3.6pl migration and invasion. We measured the induction of uPA and uPAR following treatment of cells with IGF-I and HGF using immunoprecipitation and Western blot analysis. The importance of uPA and uPAR on L3.6pl cell migration and invasion was studied by inhibiting their activities with amiloride and antibodies before cytokine treatment. In an orthotopic mouse model of human pancreatic carcinoma, we evaluated the effect of anti-uPAR monoclonal antibodies with and without gemcitabine on primary tumor growth, retroperitoneal invasion, and hepatic metastasis. IGF-I and HGF mediated cell migration and invasion in L3.6pl cells. In addition, IGF-I and HGF induced uPA and uPAR expression in L3.6pl cells. In vitro, blockade of uPA and uPAR activity inhibited IGF-I- and HGF-mediated cell migration and invasion. Treatment of mice with anti-uPAR monoclonal antibody significantly decreased pancreatic tumor growth and hepatic metastasis and completely inhibited retroperitoneal invasion. Our study shows the importance of the uPA/uPAR system in pancreatic carcinoma cell migration and invasion. These findings suggest that uPAR is a potential target for therapy in patients with pancreatic cancer.