Notch has been linked to β-catenin-dependent tumorigenesis; however, the mechanisms leading to Notch activation and the contribution of the Notch pathway to colorectal cancer is not yet understood. By microarray analysis, we have identified a group of genes downstream of Wnt/β-catenin (down-regulated when blocking Wnt/β-catenin) that are directly regulated by Notch (repressed by γ-secretase inhibitors and up-regulated by active Notch1 in the absence of β-catenin signaling). We demonstrate that Notch is downstream of Wnt in colorectal cancer cells through β-catenin-mediated transcriptional activation of the Notch-ligand Jagged1. Consistently, expression of activated Notch1 partially reverts the effects of blocking Wnt/β-catenin pathway in tumors implanted s.c. in nude mice. Crossing APC ^{Min /+} with Jagged1 ^+/Δ mice is sufficient to significantly reduce the size of the polyps arising in the APC mutant background indicating that Notch is an essential modulator of tumorigenesis induced by nuclear β-catenin. We show that this mechanism is operating in human tumors from Familial Adenomatous Polyposis patients. We conclude that Notch activation, accomplished by β-catenin-mediated up-regulation of Jagged1, is required for tumorigenesis in the intestine. The Notch-specific genetic signature is sufficient to block differentiation and promote vasculogenesis in tumors whereas proliferation depends on both pathways.

Summary: The FOXO3 (Forkhead/winged helix box class O 3) transcription factor is a crucial regulator of haematopoietic cell fate that controls proliferation and apoptosis, among other processes. Despite the central role of FOXO3 as a tumour suppressor and phosphatidylinositol 3‐kinase (PI3K)/AKT effector, little is known about its involvement in mantle cell lymphoma (MCL) biology. This study investigated the expression and activity of FOXO3 in MCL cell lines and in primary cultures. We analysed the expression of key FOXO regulators and targets, and studied the effect of modulators of FOXO function on cell viability and apoptosis. FOXO3 was constitutively inactivated in MCL cell lines, and showed cytoplasmic localization in patient‐derived cells. PI3K and AKT, but not mammalian target of rapamycin (mTOR), inhibitors induced FOXO3 nuclear translocation and activation in correlation with their impact on MCL proliferation and survival. Moreover, FOXO3‐defective cells were resistant to PI3K/AKT inhibitors. Reactivation of FOXO function with a nuclear export inhibitor had a profound effect on cell viability, consistent with FOXO3 nuclear accumulation. Interestingly, inhibition of FOXO3 nuclear export enhanced the effect of doxorubicin. Taken together, our results confirm that FOXO3 is a relevant regulator of proliferation and apoptosis in MCL, and suggest that reactivation of FOXO3 function might be a useful therapeutic strategy in MCL patients.

Purpose: Nilotinib plus doxorubicin showed to be synergistic regarding apoptosis in several sarcoma cell lines. A phase I/II trial was thus designed to explore the feasibility of nilotinib as coadjuvant of doxorubicin by inhibiting MRP-1/P-gp efflux activity. The phase I part of the study is presented here. Patients and Methods: Nilotinib 400 mg/12 hours was administered in fixed dose from day 1 to 6, and doxorubicin on day 5 of each cycle. Three dose escalation levels for doxorubicin at 60, 65, and 75 mg/m2 were planned. Cycles were repeated every 3 weeks for a total of 4 cycles. Eligible subtypes were retroperitoneal liposarcoma, leiomyosarcoma, and unresectable/metastatic high-grade chondrosarcoma. Results: Thirteen patients were enrolled: 7 chondrosarcoma, 4 liposarcoma, and 2 leiomyosarcoma. In 46 cycles administered, the most relevant grade 3/4 adverse effects per patient were neutropenia 54%, febrile neutropenia 15%, and asthenia 8%. No cardiac toxicity was observed. Only one dose-limiting toxicity (febrile neutropenia) was reported in the third dose level. With regard to efficacy, 1 partial response (1 liposarcoma), 9 stable diseases (5 chondrosarcoma, 2 liposarcoma, 1 leiomyosarcoma), and 3 progressive diseases (2 chondrosarcoma and 1 leiomyosarcoma) were present. ABCB1 and ABCC1 RNA expression levels decreased by 58.47-fold and 1.47-fold, respectively, on day 5 of the cycle. Conclusions: Combination of MRP-1/P-gp inhibitor, nilotinib, as coadjuvant with doxorubicin is feasible; it appears not to add substantial toxicity compared with doxorubicin alone. Pharmacodynamic study supports this concept. The recommended dose for the phase II part for doxorubicin was 75 mg/m2. Clin Cancer Res; 24(21); 5239–49. ©2018 AACR.

Precision medicine is already a reality in the field of oncology given that the selection and use of biomarker-driven therapies has clearly improved patient survival. Furthermore, a new, minimally ...