Anti-TSC2 monoclonal antibody, clone Z431

Cell signaling important for homeostatic regulation of colonic epithelial cells (CECs) remains poorly understood. Mammalian target of rapamycin complex 1 (mTORC1), a protein complex that contains the serine-threonine kinase mTO R, mediates signaling that underlies the control of cellular functions such as proliferation and autophagy by various external stimuli. We here show that ablation of tuberous sclerosis complex 2 (Tsc2), a negative regulator of mTORC1, specifically in intestinal epithelial cells of mice resulted in increased activity of mTORC1 of, as well as increased proliferative activity of, CECs. Such Tsc2 ablation also reduced the population of Lgr5-positive colonic stem cells and the expression of Wnt target genes in CEC s. The stimulatory phosphorylation of the kinase Akt and inhibitory phosphorylation of glycogen synthase kinase 3 beta were both markedly decreased in the colon of the Tsc2 conditional knockout (CKO) mice. Development of colonic organoids with cryptlike structures was enhanced for Tsc2 CKO mice compared with control mice. Finally, Tsc2 CKO mice manifested increased susceptibility to dextran sulfate sodium-induced colitis. Our results thus suggest that mTORC1 activity promotes the proliferation of, as well as the expression of Wnt target genes in, CEC s and thereby contributes to colonic organogenesis and homeostasis.

Lung cancer ranks as the most common cancer and leading cause of cancer-related deaths worldwide. Of all lung cancer types, non-small cell lung cancer (NSCLC) accounts for 85 percent of all cases. The high mortality of NSCLC occurs mainly because of poor prognosis in patients with recurrent and metastatic cancer. Cisplatin-containing chemotherapy is the first option to treat recurrent and metastatic NSCLC. Additionally, targeted therapy plays an important role to prolong life in patients. Currently, EGFR inhibitors are the most important targeted anti-cancer drugs for patients with EGFR mutations in the clinical setting. Another important kinase inhibitor for targeted therapy is the MEK inhibitor, Trametinib, which is often used for patients with BRAF mutation or MEK/ERK activation in the tumors. In this study, we determined whether a combination of the pan-ErbB kinase inhibitor, Afatinib, and MEK inhibitor, Trametinib, could more effectively inhibit NSCLC cell proliferation when compared to either single treatment. We found that Afatinib inhibited phosphorylation of EGFR, HER2, HER3, and HER4, as well as Akt, whereas it elevated ERK phosphorylation. Conversely, Trametinib treatment led to ERK inhibition, but induced Akt phosphorylation. However, the combination of Afatinib and Trametinib inhibited all of the above-mentioned signaling pathways and synergistically suppressed cell proliferation. Our data indicate that co-targeting of ErbB family and MEK/ERK pathways through a combination of Afatinib and Trametinib could be a potential effective strategy to treat NSCLC.