Disruption of the AKT pathway inhibits metastasis in an orthotopic model of head and neck squamous cell carcinoma

Abstract

Introduction Merck's MK-2206 is an orally active, allosteric inhibitor of AKT; a component of the phosphatidylinositol-3 kinase (PI3K) pathway. The PI3K-AKT pathway is a downstream signaling pathway that has recently been found to play an important role in head and neck squamous cell carcinoma (HNSCC). Here we examine the role AKT inhibitors may play in preventing metastasis in HNSCC. Methods Cell migration after 24 hour treatment with sub-therapeutic doses of MK-2206 was assessed using an ELISA assay in 4 HNSCC cell lines: CAL27, FaDu, SCC-1 and SCC-5). In vitro effect of MK-2206 on cell migration was assessed by making linear scratches in culture plates after cell lines were grown to confluency. Images were taken at 8, 16 and 24 hours. In vivo analysis was performed on Nude mice with human SCC1-orthotopic tongue tumors. After tumors were allowed to grow for 7 days, mice were treated with oral dosing of 120 mg/kg of MK-2206 every other day for 2 weeks. Tumor size was assessed after each treatment using a pair of digital calipers. At the end of the treatment period, mice were sacrificed and cervical lymph nodes were assessed for metastasis using flourescent imaging of tumor cell markers. Results Sub-therapeutic doses of MK-2206 was sufficient to significantly reduce cell migration a in FaDu, SCC-1 and SCC-5 cell lines (p<0.001) but not in Cal27 (p=0.09). In vitro scratch test results in SCC-1 cells yielded significant reduction in cell movement at 8, 16 and 14 hours (p<0.001). In vivo orthotopic model yielded significant reduction in primary tumor size (p=0.04) and reduction in positive cervical lymph nodes (p=0.01) between treatment and control mice. In addition we found 100% survival of MK-2206 treated mice after two weeks of treatment compared with 70 % survival in our control group (p=0.03). Conclusions Treatment with MK-2206 is sufficient to inhibit HNSCC chemotaxis and migration in vitro. In an orthotopic model, treatment with MK-2206 reduces primary tumor size and cervical metastasis while improving survival. MK-2206 currently being used in phase II clinical trials for combination treatment of metastatic solid tumors and may be useful for treating HNSCC as well.

Deltonin induced both apoptosis and autophagy in head and neck squamous carcinoma FaDu cell

“…Akt activation occurs by phosphorylation at T308 and S473 residues and has been validated as a critical step in the initiation and maintenance of metastatic tumors [47]. Chemical interaction of Akt is reported to cause apoptosis, and inhibit chemotaxis and migration FaDu cells in vitro [48]. When treated with deltonin, downregulated levels both dephosphorylated Akt at Ser473 and p-mTOR at s2448 were found in FaDu cells ( Figure 5C and 5D), suggesting a profound effect of deltonin on Akt/mTOR signaling network in FaDu cells.…”

Targeting the PI3K/AKT/mTOR pathway in squamous cell carcinoma of the head and neck

“…Inhibitors of AKT fall into two classes: catalytic inhibitors, which compete for the ATP-binding site, and allosteric inhibitors, which act away from this catalytic site. Subtherapeutic doses of the allosteric AKT inhibitor MK-2206 have been shown to significantly reduce cell migration in the FaDu model, with 100% survival of treated mice after 2 weeks compared with 70% survival in a control group (p < 0.05) [58]. Another study demonstrated a synergistic effect of MK-2206 and paclitaxel in combination in SCCHN cell lines through an interaction with autophagy trafficking, leading to increased apoptosis [59].…”

Garcinol, a Polyisoprenylated Benzophenone Modulates Multiple Proinflammatory Signaling Cascades Leading to the Suppression of Growth and Survival of Head and Neck Carcinoma

“…AKT/mTOR/S6K1 is the major antiapoptotic pathway that can confer the survival advantage and also mediate the resistance of HNSCC cells against various chemotherapeutic agents (27,28). We therefore investigated whether garcinol can downregulate the constitutive AKT/mTOR/ S6K1 activation in HNSCC cells.…”