Immunohistochemical and genetic evaluations of epidermal growth factor receptor (EGFR) in oral squamous cell carcinoma

Tetrahydrobenzothiophene derivatives ameliorate Mia PaCa-2 cell progression and induces apoptosis via inhibiting EGFR2 tyrosine kinase signal

A series of new thiophene analogues with acarbonitrile-basedmoiety were designed and synthesized via structural optimization. The conjugates were assessed for their in-vitro cytotoxic activity against a human pancreatic cancer cell line (Mia PaCa-2) and among them compound 5b showed IC50 value of 13.37 ± 2.37 μM. The compounds 5b (20 µM & 25 µM) and 7c (30 & 35 µM) also showed reduced clonogenicity, enhanced ROS and decreased mitochondrial membrane potential in Mia PaCa-2 cells. Treatment with these compounds also increased apoptotic population as evident with the double staining assay. Among the evaluated series, compounds 5b, 5g, 7c, and 9a attained a greater inhibitory potency than first generation's reversible EGFR inhibitor, Gefitinib. EGFR2 enzyme inhibitory studies revealed that 5b efficiently and arbitrarily suppressed the development of EGFR2 dependent cells and inhibited the enzymatic activity with an IC50 value of 0.68 µM; interestingly, the most effective molecule 5b with N-methyl piperazine substitution, has 1.29-fold greater potency than well-known EGFR inhibitor Gefitinib and increased Gefitinib's anti-growth impact with 2.04 folds greater against Mia PaCa-2. The in-vitro studies were validated with in-silico docking studies wherein compounds 5b and 7c exhibited binding energies of -8.2 and -7.4 Kcal/mol respectively. The present study reveals that tetrahydrobenzothiophene based analogues could be a promising lead for the evolution of potent chemo preventives over pancreatic cancer.

Riparsaponin isolated from Homonoia riparia Lour induces apoptosis of oral cancer cells

Homonoia riparia Lour (Euphorbiaceae) is a known source of herbal medicine in China, and riparsaponin (RSP) is an active constituent isolated from H. riparia. The aim of the present study was to investigate the antitumor effect of RSP on human oral carcinoma cells and its potential underlying molecular mechanism. RSP was isolated from roots of H. riparia and identified using nuclear magnetic resonance. An MTT assay was used to evaluate the cytotoxicity of RSP on human oral carcinoma cells. Subsequently, DAPI staining was performed to investigate the apoptotic effect of RSP. To investigate the potential underlying molecular mechanism of action of RSP, western blotting was performed to determine the expression of cleaved caspase 3/9, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), Bcl-2-associated death promoter (Bad), epithelial cadherin (E-CAD), c-MET, matrix metalloproteinase (MMP)-2 and MMP-9. RSP exhibited a significant anti-proliferative effect on oral carcinoma cells at concentrations between 10 and 200 µg/ml via apoptosis. Following treatment with RSP (20, 40 and 80 µg/ml), expression of cleaved caspase-3 (P<0.05, P<0.01 and P<0.01, respectively), cleaved caspase-9 (P<0.01), Bad (P<0.01), Bax (P<0.01), c-MET (P<0.01), MMP-2 (P<0.01) and MMP-9 (P<0.01) in oral carcinoma cells was increased significantly compared with the control group, whereas expression of Bcl-2 (P<0.01) and E-CAD (P<0.01) was decreased. These results suggest that RSP possessed notable antitumor activity against oral squamous cell carcinoma by inducing mitochondria-mediated apoptosis.

Inhibition of EGF-induced migration and invasion by sulfated polysaccharide of Sepiella maindroni ink via the suppression of EGFR/Akt/p38 MAPK/MMP-2 signaling pathway in KB cells

SIP-SII, the sulfated Sepiella maindroni ink polysaccharide (SIP), has been manifested to possess anti-tumor and anti-metastasis activity in vivo and in vitro. In the present study, we evaluated its inhibitory effect on the epidermal growth factor (EGF)-induced migration and invasion of human epidermoid carcinoma cell (KB cell line) as well as the related signaling pathways. The results of MTT assay indicated that SIP-SII inhibited the proliferation of KB cells in a concentration and time dependent manner. Notably, the attenuation of cell growth by SIP-SII was enlarged in the presence of EGF. The wound healing assay and transwell invasion assay were used to evaluate the effect of SIP-SII on the EGF-induced migration and invasion of KB cells and the results showed that SIP-SII markedly attenuated the EGF-induced migration and invasion. Besides, the EGF-induced matrix metalloproteinase-2 (MMP-2) expression was also suppressed by SIP-SII. However, SIP-SII showed no significant inhibition of the EGF-induced matrix metalloproteinase-9 (MMP-9) expression. Further research revealed that SIP-SII decreased the EGF-induced phosphorylation of epidermal growth factor receptor (EGFR), Akt and p38, but no significant suppression on EGF-induced phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2) and c-Jun N-terminal kinases (JNK) by SIP-SII treatment was observed. The involvement of EGFR/Akt/p38 pathway was confirmed by evidence that SIP-SII would enlarge the inhibitory effect of the specific signal pathway inhibitors. These results indicate that SIP-SII has the potential to be used as the inhibitor of tumor metastasis especially for cancers characterized by over-activation of EGF/EGFR signaling.