Whole genome expression profiling in chewing-tobacco-associated oral cancers: a pilot study

Abstract

The current study was undertaken with a view to identify differential biomarkers in chewing-tobacco-associated oral cancer tissues in patients of Indian ethnicity. The gene expression profile was analyzed in oral cancer tissues as compared to clinically normal oral buccal mucosa. We examined 30 oral cancer tissues and 27 normal oral tissues with 16 paired samples from contralateral site of the patient and 14 unpaired samples from different oral cancer patients, for whole genome expression using high-throughput IlluminaSentrix Human Ref-8 v2 Expression BeadChip array. The cDNA microarray analysis identified 425 differentially expressed genes with >1.5-fold expression in the oral cancer tissues as compared to normal tissues in the oral cancer patients. Overexpression of 255 genes and downregulation of 170 genes (p < 0.01) were observed. Further, a minimum twofold overexpression was observed in 32 genes and downregulation in 12 genes, in 30-83% of oral cancer patients. Biological pathway analysis using Kyoto Encyclopedia of Genes and Genome Pathway database revealed that the differentially regulated genes were associated with critical biological functions. The biological functions and representative deregulated genes include cell proliferation (AIM2, FAP, TNFSF13B, TMPRSS11A); signal transduction (FOLR2, MME, HTR3B); invasion and metastasis (SPP1, TNFAIP6, EPHB6); differentiation (CLEC4A, ELF5); angiogenesis (CXCL1); apoptosis (GLIPR1, WISP1, DAPL1); and immune responses (CD300A, IFIT2, TREM2); and metabolism (NNMT; ALDH3A1). Besides, several of the genes have been differentially expressed in human cancers including oral cancer. Our data indicated differentially expressed genes in oral cancer tissues and may identify prognostic and therapeutic biomarkers in oral cancers, postvalidation in larger numbers and varied population samples.

Effect of genetic variation in microRNA binding site in WNT1-inducible signaling pathway protein 1 gene on oral squamous cell carcinoma susceptibility

“…Smoking is one of the crucial risk factors for OSCC [31, 33]. In a pilot study, whole genome expression profiling of Indian patients with tobacco chewing-associated oral cancers implicated that WISP1 is one of the representative apoptosis-related deregulated genes in oral cancer [34]. Chen et al revealed that WISP1 was overexpressed in non–small cell lung carcinoma (NSCLC) samples compared with their normal lung tissue counterparts, implicating that WISP1 might act as an oncoprotein in NSCLC [10].…”

Absent in melanoma 2 proteins in the development of cancer

“…A study that analyzed expression of AIM2 protein in colon cancer tissue microarray (TMA) [29] or studies that analyzed AIM2 mRNA levels in colorectal [29,30] and prostate [20] cancer specimen indicated that reduced or loss of AIM2 expression in cells is associated with cancer development and its progression to an advanced stage. However, increased levels of the AIM2 mRNA and protein have been reported in a number of inflammation and virus-associated cancers [31][32][33][34][35][36]. Therefore, given that AIM2 expression is also increased in senescent cells [19], further work will be needed to determine whether cancer therapy-induced accumulation of senescent cells in tumors contributes to the observed increased levels of AIM2 mRNA or protein.…”

“…Furthermore, in lung cancer tissues, high-grade ADC expressed more inflammasome components and products than low-grade ADC [33]. Similarly, in chewing-tobacco-associated oral cancer tissues, AIM2 mRNA levels were higher than clinically normal oral buccal mucosa [34].…”

“…Similarly, endogenous constitutive levels of AIM2 protein in human THP-1 monocytic cancer cells were detected in the cytoplasm and treatment of cells with PMA that resulted in differentiation of cells increased the levels of AIM2 protein and the protein was detected in the cytoplasm [38]. Notably, IFN-c treatment of THP-1 or PMA-treated THP-1 cells robustly increased AIM2 protein levels in the cytoplasm and HNPCC-associated small bowl cancer (SBC) Loss of expression (frame-shift mutation) Poor prognosis [27] Colorectal cancer Loss of expression (microsatellite instability) Poor prognosis [29,30] Nasopharyngeal carcinoma (NPC) Overexpression Correlated with survival [31] Oral squamous cell carcinoma (OSCC) Overexpression p53-dependent inhibition [32] Non-small cell lung cancer (NSCLC) Overexpression Poor prognosis [33] Oral cancer Overexpression Not known [34] Cervical cancer Overexpression (amplification of 1q22-23 region) Not known [75] D. Choubey very little protein was detected in the nucleus. Furthermore, constitutively overexpressed human AIM2 protein in the murine AKR-2B fibroblasts (spontaneously immortalized) was primarily detected in the cytoplasm [37].…”

Molecular alterations associated with chronic exposure to cigarette smoke and chewing tobacco in normal oral keratinocytes

“…35,36 In comparison, few studies discuss the impact of chewing or other forms of smokeless tobacco on gene expression using high-throughput techniques. [37][38][39] Our group has previously reported the proteome-wide alterations in oral keratinocytes upon chronic exposure to smokeless tobacco and identified stearoyl CoA desaturase as a potential therapeutic target in head and neck squamous cell carcinoma. 40 Metabolic differences have been reported between smokers and snuff users but the molecular/proteomic alterations between smokers and tobacco chewers are not well elucidated.…”