pi103 and Carcinoma--Squamous-Cell

To investigate the effects of a dual phosphoinosmde-3-kinase (PI3K)/ mammalian target of rapamycin (mTOR) inhibitor, PI-103, cooperating with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the laryngeal squamous carcinoma Hep-2 cells.. Hep-2 cells were divided into 7 groups: LY294002 group, Rapamycin group, PI-103 group, LY294002+ TRAIL group, Rapamycin+ TRAIL group, PI-103+ TRAIL group and control group.The cell cycle and apoptosis of Hep-2 cells were assessed by flow cytometry.For PI-103 group, PI-103+ TRAIL group and control group, migration and invasion ability were measured by transwell migration and invasion assay respectively.The expression of relative proteins in apoptosis and PI3K/AKT/mTOR signal pathway was examined by Western blotting.. Combination of PI-103 and TRAIL could make cell cycle arrest at S phase (G1: 1.80%±0.30%; G2: 0.00), inhibit cell proliferation, and enhance apoptosis (66.78%±2.93%) (P<0.05). Combination of PI-103 and TRAIL could statistically decrease the migration and invasion number of Hep-2 cells (17.0±3.4, 18.4±5.4) than that of PI-103 group (41.2±3.8, 41.6±4.7). PI-103 could inhibit PI3K/AKT/mTOR signal pathway by decreasing the protein expression of p-AKT and p-4E-BP1.Comparing with the control group, the expression of cysteinyl aspartate specific proteinase (Caspase) 9, 8, 3 were increased while the expression of Cyclin D1, Cyclin E1, p-AKT, p-4E-BP1 were decreased in PI-103 and PI-103+ TRAIL group (P<0.05).. Enhanced anti-tumor effects was observed by combination of PI-103 and TRAIL on laryngeal cancer cells in vitro and this combined administration might be a promising strategy for clinical treatment of laryngeal cancer.

Topics: Animals; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Chromones; Cyclin D1; Cyclin E; Furans; Head and Neck Neoplasms; Humans; Laryngeal Neoplasms; Morpholines; Oncogene Proteins; Phosphatidylinositol 3-Kinases; Pyridines; Pyrimidines; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; TNF-Related Apoptosis-Inducing Ligand; TOR Serine-Threonine Kinases

K-RAS mutated (K-RASmut) non-small cell lung cancer (NSCLC) cells are resistant to EGFR targeting strategies. We investigated the impact of K-RAS activity irrespective of mutational status in the EGFR-independent increase in clonogenic cell survival. An analysis of the K-RAS activity status revealed a constitutively high K-RAS activity in K-RASmut NSCLC cells and also in head and neck squamous cell carcinoma (HNSCC) cells overexpressing wild-type K-RAS (K-RASwt). Similar to K-RAS-mutated cells, increased K-RAS activity in HNSCC cells overexpressing K-RASwt was associated with the stimulated production of the EGFR ligand amphiregulin and resistance to EGFR tyrosine kinase (EGFR-TK) inhibitors such as erlotinib. Expression of mutated K-RAS stimulated Akt phosphorylation and increased plating efficiency. Conversely, knockdown of K-RAS in K-RASmut NSCLC cells and in HNSCC cells presenting overexpression of K-RASwt resulted in sensitization to the anti-clonogenic activity of erlotinib. K-RAS activity results in EGFR-dependent and EGFR-independent Akt activity. The short-term treatment (2 h) of cells with EGFR-TK or PI3K inhibitors (erlotinib and PI-103) resulted in the repression of Akt activation, whereas long-term treatment (24 h) with inhibitors led to the reactivation of Akt and improved clonogenicity. The Akt re-activation was MAPK-ERK2-dependent and associated with a lack of complete response to anti-clonogenic activity of PI-103. A complete response was observed when PI-103 was combined with MEK inhibitor PD98059. Together, clonogenicity inhibition in tumor cells presenting constitutive K-RAS activity independent of K-RAS mutational status can be achieved by targeting of EGFR downstream pathways, i.e., PI3K alone or the combination of PI3K and MAPK inhibitors.

Topics: Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Clone Cells; Drug Synergism; ErbB Receptors; Erlotinib Hydrochloride; Flavonoids; Furans; Head and Neck Neoplasms; Humans; Lung Neoplasms; Mitogen-Activated Protein Kinase 1; Oncogene Protein v-akt; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); Pyridines; Pyrimidines; Quinazolines; ras Proteins; Signal Transduction

The PI3K-Akt signalling pathway is a well-established driver of cancer progression. One key process promoted by Akt phosphorylation is tumour cell motility; however the mechanism of VEGF-induced Akt phosphorylation leading to motility remains poorly understood. Previously, we have shown that Akt phosphorylation induced by different factors causes both stimulation and inhibition of motility in different cell types. However, differential phosphorylation of Akt at T308 and S473 residues by VEGF and its role in head and neck cancer cell motility and progression is unknown. The cell lines investigated in this study exhibited a change in phosphorylation of Akt in response to VEGF. However, in terms of motility, VEGF stimulated oral cancer and its associated cell lines, but not normal keratinocytes or oral mucosal fibroblasts. The addition of a PI3 kinase and mTOR inhibitor, inhibited the phosphorylation of Akt and also effectively blocked VEGF-induced oral cancer cell motility, whereas only the PI3 kinase inhibitor blocked oral cancer associated fibroblast cell motility. This study therefore discloses that two different mechanisms of Akt phosphorylation control the motility potential of different cell lines. Akt phosphorylated at both residues controls oral cancer cell motility. Furthermore, immunohistochemical analysis of VEGF positive human head and neck tumour tissues showed a significant increase in Akt phosphorylation at the T308 residue, suggesting that pAkt T308 may be associated with tumour progression in vivo.

Topics: Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Movement; Chromones; Furans; Humans; Morpholines; Mouth Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Pyridines; Pyrimidines; Vascular Endothelial Growth Factor A