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Oral Submucous Fibrosis (OSMF) is a chronic debilitating disease more frequently found in the South East Asian population. This disease poses a public health priority, as it is grouped under oral potentially malignant disorders, with malignant transformation rates of around 7 to 13%. Hence, early identification of high-risk OSMF patients is of the utmost importance to prevent malignant transformation. Proteomic expression profiling is a promising method for identifying differentially expressed proteins for disease prognosis and risk stratification in OSMF. In this study, overexpressed proteins in OSMF, OSMF transformed into oral squamous cell carcinoma (OSCC) and normal tissues were evaluated by proteomic analysis using two-dimensional electrophoresis (2DE) and mass spectrometry, which revealed 23 upregulated proteins. Validation was done using immunohistochemistry for three secretory proteins, namely 14-3-3ε (n = 130), carbonic anhydrase 1 (CA 1) (n = 125) and heat shock protein 70 (HSP 70) (n = 117), which showed significant overexpression in OSMF, OSCC compared to normal. The present study is the first of its kind in India to the best of our knowledge, assessing the altered expression of proteins in OSMF and OSMF which has undergone malignant transformation, obtaining a better knowledge of the molecular pathways involved in the disease progression. The current study shows that the biomarkers studied can be potentially useful for risk stratification of OSMF to OSCC serving as novel targets for therapeutic intervention. Clinical validation of the targets can further pave way for precision medicine to improve the quality of life in OSMF patients.

Oral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer with high morbidity and mortality rates, despite multimodality management. There are currently no clinically relevant molecular markers that identify patients at higher risk of recurrence and failure. We undertook 2D-DIGE proteomic profiling to study the differentially expressed proteins in OTSCC evaluating their role in prognosis. 2D-DIGE coupled with tandem mass spectrometry was performed on tissues obtained from early staged OTSCC along with its paired apparently adjacent normal tissue samples ( n = 10 ). Top upregulated protein was validated using immunohistochemistry ( n = 345 ), comprising of retrospective early stage OTSCC ( n = 150 ) and prospective series of oral precancers, normal, and oral cancers ( n = 195 ). Saliva samples collected from oral cancer and precancer samples were analyzed by ELISA ( n = 146 ). We found statistically significant differential expression in 151 proteins out of 700 proteins quantified. Top ten differentially regulated proteins were identified using mass spectrometry analysis. We found vimentin, the mesenchymal protein, to be the most upregulated protein in tongue tumor tissues compared to adjacent apparent normal tissues. Vimentin was found to be significantly overexpressed in oral precancers along with cancers compared to normal tissues. The vimentin expression correlated significantly with differentiated states of oral precancers and cancers. Vimentin was also detected at significantly higher levels in saliva collected from oral precancer and cancer patients compared to normal healthy volunteers. Validation of vimentin in an independent series of retrospective early staged OTSCC showed that the vimentin expression is significantly associated with treatment failures and poorer DFS. The vimentin expression is useful as both poor prognostic and early detection marker in oral cancer. Vimentin detection in saliva can be a diagnostic test to detect oral precancers that may have malignant potential, needing closer follow-up, and disease monitoring.

Background : Oral tongue squamous cell carcinoma (OTSCC) is an aggressive cancer with high morbidity and mortality rates, despite multimodality management. There are currently no clinically relevant molecular markers to help identify patients at a higher risk of recurrence and failure. Methods: 2D-DIGE coupled with tandem mass spectrometry was performed on tissues obtained from early staged OTSCC along with its paired apparently adjacent normal tissue samples (n=10). Top upregulated protein was validated using another independent set of tissue samples by Immunohistochemistry (n=346), comprising of retrospective early stage OTSCC (n=150) and prospective series of oral pre-cancers, normal and oral cancers (n=195). For further validation of protein expression, saliva samples collected from Oral Cancer and pre-cancer samples were analysed by ELISA (n=80). Results: We found vimentin, the mesenchymal protein to be the most upregulated protein in tongue tumour tissues compared to adjacent apparent normal tissues. Vimentin was found to be significantly overexpressed in oral pre-cancers along with cancers compared to normal tissues. Conclusion: Vimentin detection in saliva can be useful diagnostic test to detect oral precancers that may have malignant potential needing closer follow up. Salivary ELISA for vimentin can additionally be useful for disease monitoring in oral cancers.

Background: Gastric Cancer (GC) remains a major global health problem due to a poor understanding of its progression at the molecular level and a lack of early detection or diagnosis. Early detection is highly crucial for improving prognosis. The incidence of GC is very high in countries, like India, due to the limitations among the established biomarkers for GC owing to poor sensitivity and specificity. Objective: This study aimed to identify the novel biomarkers from serum samples obtained from GC patients compared to healthy subjects. Methods: Serum samples from GC patients were analyzed by two-Dimensional Gel Electrophoresis (2DGE) coupled with tandem Mass Spectrometry (MS), including both Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-ToF) and Liquid Chromatography-MS (LC-MS/MS) analysis. Identified proteins were further analyzed by gene ontology and protein interaction studies. Results: A total of 73 protein spots were detected in 2DGE image analysis. Among them, seven differentially-expressed proteins were identified using MS analyses, including serotransferrin/ transferrin, albumin, ceruloplasmin, C-reactive protein (CRP), fibrinogen γ-chain (FGG), and two unreported novel proteins, immunoglobulin kappa constant (IgκC) region and Homo sapiens zinc finger protein 28 (ZNF28) homolog. Among these proteins, serotransferrin, albumin, ceruloplasmin, FGG, and ZNF28 were down-regulated in GC samples (p Conclusion: Most of the differentially expressed proteins were involved in angiogenesis, plasminogen-activating cascade, and blood coagulation pathways which are known to play a critical role in gastric tumorigenesis. Our current results provide a panel of candidate biomarkers for GC with novel biomarkers which have not been reported earlier.

c-Myc is a proto-oncogene controlling expression of multiple genes involved in cell growth and differentiation. Although the functional role of c-Myc as a transcriptional regulator has been intensively studied, targeting this protein in cancer remains a challenge. Here, we report a trimodal regulation of c-Myc function by the Ras effector, Ras-association domain family member 7 (RASSF7), a nonenzymatic protein modulating protein–protein interactions to regulate cell proliferation. Using HEK293T and HeLa cell lines, we provide evidence that RASSF7 destabilizes the c-Myc protein by promoting Cullin4B-mediated polyubiquitination and degradation. Furthermore, RASSF7 competed with MYC-associated factor X (MAX) in the formation of a heterodimeric complex with c-Myc and attenuated its occupancy on target gene promoters to regulate transcription. Consequently, RASSF7 inhibited c-Myc–mediated oncogenic transformation, and an inverse correlation between the expression levels of the RASSF7 and c-Myc genes was evident in human cancers. Furthermore, we found that RASSF7 interacts with c-Myc via its RA and leucine zipper (LZ) domains and LZ domain peptide is sufficient to inhibit c-Myc function, suggesting that this peptide might be used to target oncogenic c-Myc. These results unveil that RASSF7 and c-Myc are functionally linked in the control of tumorigenesis and open up potential therapeutic avenues for targeting the “undruggable” c-Myc protein in a subset of human cancers.

Ras-association domain family (RASSF) proteins are encoded by numerous tumor suppressor genes that frequently become silenced in human cancers. RASSF10 is downregulated by promoter hypermethylation in cancers and has been shown to inhibit cell proliferation; however, the molecular mechanism(s) remains poorly understood. Here, we demonstrate for the first time that RASSF10 inhibits Cdk1/cyclin-B kinase complex formation to maintain stable levels of cyclin-B for inducing mitotic arrest during cell cycle. Using LC-MS/MS, live cell imaging, and biochemical approaches, we identify Nucleophosmin (NPM) as a novel functional target of RASSF10 and revealed that RASSF10 expression promoted the nuclear accumulation of GADD45a and knockdown of either NPM or GADD45a, resulting in impairment of RASSF10-mediated G2/M phase arrest. Furthermore, we demonstrate that RASSF10 is a substrate for the E3 ligase ring finger protein 2 (RNF2) and show that an NPM-dependent downregulation of RNF2 expression is critical to maintain stable RASSF10 levels in cells for efficient mitotic arrest. Interestingly, the Kaplan-Meier plot analysis shows a positive correlation of RASSF10 and NPM expression with greater gastric cancer patient survival and the reverse with expression of RNF2, suggesting that they may have a role in cancer progression. Finally, our findings provide insights into the mode of action of the RASSF10/NPM/RNF2 signaling cascade on controlling cell proliferation and may represent a novel therapeutic avenue for the prevention of gastric cancer metastasis.