Abstract 31P
Background
Oral cancer has been a major public health issue worldwide, with significant incidence and mortality rates. Progression of oral cancer involves step-wise advancement from a dysplastic state to carcinoma in situ and metastasis. Early detection of oral cancer is the key to improving the survival rate in patients. Homeobox genes are evolutionarily conserved transcription factors that act as master regulators in normal development. HOX gene deregulation has been evident in several cancers. Our research with oral cancer patients, monolayer and 3D-engineered cell lines has shown HOXD10, a member of the HOXD cluster, to be differentially expressed in oral cancer tissue and cell lines compared to the normal controls. HOXD10, during normal development, is involved in limb bud formation and limb development. This study aims to understand more about the involvement of HOXD10 in oral cancer.
Methods
Matched normal oral cancer tissues from patients across different stages were recruited (IEC348/2018), and a panel of oral cell lines were employed in the study. The gene expression and methylation status were assessed using qRT-PCR and Methyl Capture Sequencing. Putative promoter regions were characterized by Dual-Luciferase assay. Oral cancer cells were treated with DNMTi (5-aza-2-deoxycytidine (5-aza-CdR)) and HDACi (Sodium butyrate (NaB)) to study its effect on HOXD10 expression status and cellular functions. HOXD10 levels were knocked down using shRNA constructs, and cell-based functional assays were performed.
Results
HOXD10 level was significantly upregulated in oral cancer cases and oral cancer cell lines compared to the normal controls. A distinct reduction pattern was observed in the LN (-) samples and the SCC9 cell line. A positive correlation between methylation and expression was observed. Luciferase assay identified the putative promoter region +38 to -1024 bp to TSS of HOXD10 as active. 5-aza-CdR did not affect HOXD10 levels, whereas NaB treatment repressed HOXD10 levels. Functional assays related to treated cells and stable knockdown cells are being assessed.
Conclusions
Our findings suggest that HOXD10 could be a crucial oncogene in oral cancer. Understanding its role and mechanism of action could provide us with better therapeutic approaches.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
DBT/Wellcome Trust India Alliance Fellowship (Grant number - IA/CPHI/18/1/503927) awarded to Raghu Radhakrishnan.
Disclosure
All authors have declared no conflicts of interest.