Prevalence of novel gamma HPV types 223 and 225 in oral cavity and skin of Indian normal and neoplastic participants.

Gamma-papillomaviruses, though traditionally classified as cutaneotropic, actual tissue tropism is largely unexplored. This study aimed to evaluate the tissue-specific prevalence of two novel-HPV 223 and 225 in samples of oral mucosa and keratinized epithelium of varied skin parts from 226 female and male subjects, with or without neoplastic/dysplastic lesions in oral cavity or cervix. The gamma-human papillomavirus (gamma-HPV) 223 and 225 DNA presences were determined by polymerase chain reaction (PCR) ursing the HPV type-specific primers and confirmed by Sanger sequencing. Viral load in the HPV 223 and HPV 225 positive samples were determined by absolute real-time quantification method. Alpha-HPV DNA prevalence was also checked in oral mucosa to ascertain coinfection status. Novel HPV 223 was present in 4.4% (10/226) oral mucosal samples of the study population; interestingly all were females with no prevalence in their corresponding skin swab samples. Whereas, the prevalence of HPV 225 was found both in the skin and oral mucosa of 28.2% (N = 37/131) female and 17.9% (N = 17/95) male participants. Alongside, HPV 223 viral load was found to be significantly higher (p = 0.02 < 0.05) in the oral mucosa of diseased participants, whereas, HPV 225 viral load was higher in the oral mucosa of normal participants. Our results suggest that gamma-HPV 223 has its prevalence only in the oral mucosal epithelium, whereas, HPV 225 has its prevalence on both mucosal and keratinized skin epithelium, indicating its dual tropism nature.

CDKN2A-p53 mediated antitumor effect of Lupeol in head and neck cancer.

PURPOSE: The tumor suppressor protein p53 is known to control cell cycle arrest and apoptosis. Lupeol is a phytochemical that has been found to induce apoptosis in different cancer types through the extrinsic pathway. As yet, however, its role in the induction of cell cycle arrest and apoptosis through the intrinsic pathway in head and neck cancer has not been investigated. Here, we aimed at understanding the mechanism underlying the antitumor effect of Lupeol in head and neck cancer. METHODS: The antitumor effect of Lupeol on oral and laryngeal carcinomas was assessed using two in vitro 2D cell line models (HEp-2, UPCI:SCC-131) and, subsequently, an ex vivo 3D tumor explant culture platform that maintains key features of the native tumor microenvironment. The mechanism underlying Lupeol-mediated antitumor responses was delineated using MTT, colony formation, flow cytometry, immunofluorescence, Western blotting and immunohistochemistry assays. RESULTS: We found that Lupeol induced an enhanced expression of p53 in both cell line models tested and, subsequently, cell cycle arrest at the G1 phase. In addition we found that, following Lupeol treatment, p53 induced Bax expression and activated the intrinsic apoptotic pathway (as measured by Caspase-3 cleavage). Interestingly, Lupeol was also found to trigger G1 cell cycle arrest through up-regulation of the expression of CDKN2A, but not p21, resulting in inhibition of CyclinD1. In an ex vivo platform Lupeol was found to impart a potent antitumor response as defined by inhibition of Ki67 expression, decreased cell viability and concomitant activation (cleavage) of Caspase-3. Finally, we found that Lupeol can re-sensitize primary head and neck squamous cell carcinoma (HNSCC) tumor samples that had clinically progressed under a Cisplatin treatment regimen. CONCLUSION: Together, our data indicate that Lupeol may orchestrate a bifurcated regulation of neoplastic growth and apoptosis in head and neck cancers and may serve as a promising agent for the management of tumors that have progressed on a platinum-based treatment regimen.