Differential protein expressions in breast cancer between drug sensitive tissues and drug resistant tissues

Differential Protein Expression in Response to Varlitinib Treatment in Oral Cancer Cell Line: an In Vitro Therapeutic Approach

Epidermal growth factor receptor (EGFR) is the most frequently overexpressed receptor histologically exhibited by oral squamous cell carcinoma (OSCC) patients. Aberrated EGFR signaling may lead to recurrence and metastasis, thus laying the foundation of targeted therapy. Deactivating EGFR is likely to prevent downstream signaling thus resulting in apoptosis. Tyrosine kinase inhibitors (TKIs) have come into play to revert aggressiveness of OSCC. We exploited comparative proteomic analyses based on anti-EGFR potential of varlitinib, using cellular proteomes from treated and untreated groups of oral cancer cells to identify protein players functional during oral carcinogenesis. Following separation by two-dimensional electrophoresis, differentially expressed cellular proteins (varlitinib-treated and untreated cells) were analyzed and later identified using QTOF mass spectrometer. In silico analysis for protein-protein interaction was carried out using STRING. Six differentially expressed proteins were identified as binding immunoglobulin protein (BiP), heat shock protein 7 C (HSP7C), protein disulfide isomerase 1 A (PDIA1), vimentin (VIME), keratin type I cytoskeletal 14 (K1C14), and β-Actin (ACTB). Relative expression of five proteins was found to be downregulated upon varlitinib treatment, whereas only K1C14 was upregulated in treated cells compared to control. Protein network analysis depicts the interaction between BiP, PDIA1, VIME, etc. indicating their role in oral carcinogenesis. Oral cancer cells show proteome shift based on varlitinib treatment compared to corresponding controls. Our data suggest candidature of varlitinib as a potent therapeutic agent and BiP, PDIA1, HSP7C, VIME, and β-Actin as complementary/prognostic markers of OSCC.

Multifaceted role of keratins in epithelial cell differentiation and transformation

Keratins, the epithelial-predominant members of the intermediate filament superfamily, are expressed in a pairwise, tissuespecific and differentiation-dependent manner. There are 28 type I and 26 type II keratins, which share a common structure comprising a central coiled coil α-helical rod domain flanked by two nonhelical head and tail domains. These domains harbor sites for major posttranslational modifications like phosphorylation and glycosylation, which govern keratin function and dynamics. Apart from providing structural support, keratins regulate various signaling machinery involved in cell growth, motility, apoptosis etc. However, tissue-specific functions of keratins in relation to cell proliferation and differentiation are still emerging. Altered keratin expression pattern during and after malignant transformation is reported to modulate different signaling pathways involved in tumor progression in a context-dependent fashion. The current review focuses on the literature related to the role of keratins in the regulation of cell proliferation, differentiation and transformation in different types of epithelia.

Knockdown of UbcH10 enhances the chemosensitivity of dual drug resistant breast cancer cells to epirubicin and docetaxel

Breast cancer is one of the most common and lethal cancers in women. As a hub gene involved in a diversity of tumors, the ubiquitin-conjugating enzyme H10 (UbcH10), may also play some roles in the genesis and development of breast cancer. In the current study, we found that the expression of UbcH10 was up-regulated in some breast cancer tissues and five cell lines. We established a dual drug resistant cell line MCF-7/EPB (epirubicin)/TXT (docetaxel) and a lentiviral system expressing UbcH10 shRNA to investigate the effects of UbcH10 knockdown on the chemosensitivity of MCF-7/EPB/TXT cells to epirubicin and docetaxel. The knockdown of UbcH10 inhibited the proliferation of both MCF-7 and MCF-7/EPB/TXT cells, due to the G1 phase arrest in cell cycle. Furthermore, UbcH10 knockdown increased the sensitivity of MCF-7/EPB/TXT cells to epirubicin and docetaxel and promoted the apoptosis induced by these two drugs. Protein detection showed that, in addition to inhibiting the expression of Ki67 and cyclin D1, UbcH10 RNAi also impaired the increased BCL-2 and MDR-1 expression levels in MCF-7/EPB/TXT cells, which may contribute to abating the drug resistance in the breast cancer cells. Our research in the current study demonstrated that up-regulation of UbcH10 was involved in breast cancer and its knockdown can inhibit the growth of cancer cells and increase the chemosensitivity of the dual drug resistant breast cancer cells to epirubicin and docetaxel, suggesting that UbcH10 may be a promising target for the therapy of breast cancer.