Predominance of genomically defined A lineage of HPV16 over D lineage in Indian patients from eastern India with squamous cell carcinoma of the cervix in association with distinct oncogenic phenotypes.

Human papillomavirus type-16 (HPV16) is classified into lineages, A, B, C and D and 10 sub-lineages portraying variable infectivity, persistence, and cytological outcomes, however, with geographical variations. Our objective was to delineate the distinctive features of lineages among cervical squamous cell carcinoma (SCC) in the eastern region of India. A total of 145 SCC cases and 24 non-malignant specimens, harboring episomal HPV16, were included. The presence of higher proportion of lineage A over D was observed among SCC cases (86.89% A1, 8.97% D1 and 4.14% D2), while only A1 sub-lineage viruses were found among control specimens. Among the A1 viruses, an association of variants in the E5 (Y44L, I65V), E6 (L83V) genes and LCR: C7577T with SCC, with combined Odd's ratio (95% CI) of 20.5(4.61-91.25) was observed. Network analyses revealed the presence of 10 clades of lineage A viruses comprising of 64 HPV16 genomes harboring the risk alleles. High episomal HPV16 DNA copy numbers (adjusted p-value= 0.0271) and E7 mRNA expression (p-value=0.000017) predominated in SCC with lineage A, over D. Our study highlights the distinctive modalities of oncogenicity among different HPV16 lineages.

Cervical cancer subtypes harbouring integrated and/or episomal HPV16 portray distinct molecular phenotypes based on transcriptome profiling of mRNAs and miRNAs.

Heterogeneity in cervical cancers (CaCx) in terms of HPV16 physical status prompted us to investigate the mRNA and miRNA signatures among the different categories of CaCx samples. We performed microarray-based mRNA expression profiling and quantitative real-time PCR-based expression analysis of some prioritised miRNAs implicated in cancer-related pathways among various categories of cervical samples. Such samples included HPV16-positive CaCx cases that harboured either purely integrated HPV16 genomes (integrated) and those that harboured episomal viral genomes, either pure or concomitant with integrated viral genomes (episomal), which were compared with normal cervical samples that were either HPV negative or positive for HPV16. The mRNA expression profile differed characteristically between integrated and episomal CaCx cases for enriched biological pathways. miRNA expression profiles also differed among CaCx cases compared with controls (upregulation-miR-21, miR-16, miR-205, miR-323; downregulation-miR-143, miR-196b, miR-203, miR-34a; progressive upregulation-miR-21 and progressive downregulation-miR-143, miR-34a, miR-196b and miR-203) in the order of HPV-negative controls, HPV16-positive non-malignant samples and HPV16-positive CaCx cases. miR-200a was upregulated in HPV16-positive cervical tissues irrespective of histopathological status. Expression of majority of the predicted target genes was negatively correlated with their corresponding miRNAs, irrespective of the CaCx subtypes. E7 mRNA expression correlated positively with miR-323 expression among episomal cases and miR-203, among integrated cases. miR-181c expression was downregulated only among the episomal CaCx cases and negatively correlated with protein coding transcript of the proliferative target gene, CKS1B of the significantly enriched "G2/M DNA Damage Checkpoint Regulation" pathway among CaCx cases. Thus, the two CaCx subtypes are distinct entities at the molecular level, which could be differentially targeted for therapy. In fact, availability of a small molecule inhibitor of CKS1B, suggests that drugging CKS1B could be a potential avenue of treating the large majority of CaCx cases harbouring episomal HPV16.

Prevalence and age-wise distribution of Human Papillomavirus type 16/18 infections among hospital screened women of a peri-urban area in West Bengal: Impact of socio-demographic factors.

BACKGROUND: We undertook the current study on cervical Human Papillomavirus (HPV) prevalence along with cytology in women visiting the Gynecology Out-patient Department of a hospital for common gynecological ailments, subsequent to our earlier population-based study on HPV prevalence from India. METHODS: We analyzed data on cervical-cytology (Pap smears) and PCR-based molecular detection of HPV infection along with socio-demographic variables (N = 696). RESULTS: We identified 36.84% HPV-positive women amongst whom, HPV16 and 18 together predominated (79.37%) over other HPV types (20.63%). Contrarily, only 6.4% women revealed abnormal cytological lesions, of which, 46.51% were HPV-positive and 95% of such women harbored HPV16/18, while 5% harbored other HPV types. Individuals with normal cytology portrayed 36.09% HPV infections, of which, 77.97% were HPV16/18-positive and 22.03% harbored other HPV types. Overall HPV prevalence decreased significantly (ptrend  = 0.047) with increase in age, but HPV16/18 infections were significantly over-represented compared to the other HPV types across all age-groups. Specifically, HPV16 prevalence increased (p trend < 0.01) with increase in severity of cervical lesions. HPV16 prevalence did not differ between the Hindus and Muslims but HPV18 was significantly higher among the cytologically normal Muslim women (24.14%, p = 0.02), compared to the Hindus (11.91%), specifically among those ≥ 30 years of age. There was a significant (p < 0.05) overrepresentation of HPV16 prevalence among women who were users of oral contraceptive-pills, irrespective of cytology. CONCLUSIONS: Our study highlights the need for HPV16/18-based screening of cervical cancers in India considering the immense socio-cultural and genetic diversity at the population level.

Impact of viral and host DNA methylations on HPV16-related cervical cancer pathogenesis.

Epigenetic alterations within human papillomavirus (HPV) and host cellular genomes are known to occur during cervical carcinogenesis. Our objective was to analyse the influence of (1) methylation within two immunostimulatory CpG motifs within HPV16 E6 and E7 genes around the viral late promoter and their correlation, if any, with expression deregulation of host receptor (TLR9) and DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) and (2) global DNA methylation levels within CpGs of the repetitive Alu sequences, on cervical cancer (CaCx) pathogenesis. Significantly higher proportions of CaCx samples portrayed methylation in immunostimulatory CpG motifs, compared to HPV16-positive non-malignant samples, with cases harbouring episomal HPV16 showing decreased methylation compared to those with viral integration. A significant linear trend of TLR9 upregulation was recorded in the order of HPV-negative controls < HPV16-positive non-malignant samples < HPV16-positive CaCx cases. TLR9 upregulation in cases with episomal HPV16 was again higher among those with non-methylated immunostimulatory CpG motifs. Comparison of cases with HPV-negative controls revealed that DNMT3A was significantly downregulated only among integrated cases, DNMT3B was significantly overexpressed among both categories of cases, although at variable levels, while DNMT1 failed to show any deregulated expression among the cases. Global host DNA hypomethylation, also showed a significant linear increasing trend through the progressive CaCx development stages mentioned above and was most prominently higher among cases with episomal HPV16 as opposed to viral integration. Thus, HPV16 and host methylations appear to influence CaCx pathogenesis, with differential molecular signatures among CaCx cases with episomal and integrated HPV16.

Impact of genetic variations and transcriptional alterations of HLA class I genes on cervical cancer pathogenesis.

In a novel attempt to understand the variations in DNA sequences underlying HLA class I alleles associated with HPV16-related CaCx, we determined the alleles by reconstructing SNP-based haplotypes from resequencing of the most polymorphic exons 2 and 3 of HLA-A, HLA-B and HLA-C. We also determined the impact of SNPs and transcriptional alterations of the genes on CaCx. A high density of SNPs was identified from resequencing. HLA expression was determined by real-time PCR. We identified that even a single associated HLA allele had many underlying SNP-based haplotypes. Out of the most frequent (≥5%) HLA class I alleles, HLA-B*40:06 and HLA-B*15:02 respectively imparted significant risk towards and protection from CaCx as well as HPV16 infection. Employing median-joining networks to detect clusters of sequence-variations for specific HLA alleles, we found the protective SNP-based signature, GAATTTA, in all SNP-based haplotypes of HLA-B*15:02 allele. The signature was derived from seven SNPs within HLA-B which were newly associated with the disease. Contrarily, similarly derived risk-signature, TTGCGCC, mapped only to 52% of SNP-based haplotypes of HLA-B*40:06 allele. This indicated that all SNP-based haplotypes underlying a particular associated HLA allele might or might not have a single signature of risk/protection. HLA-A, HLA-B and HLA-C expressions were downregulated among CaCx cases compared to asymptomatic infections and HPV-negative controls. HLA-A and HLA-B were repressed in both cases harbouring episomal and integrated HPV16, whereas HLA-C in only the latter. Novel genetic variations and differential downregulation-patterns of HLA class I have a significant bearing on HPV16-related CaCx pathogenesis.

Complete Genome Sequences of Eight Human Papillomavirus Type 16 Asian American and European Variant Isolates from Cervical Biopsies and Lesions in Indian Women.

Human papillomavirus type 16 (HPV16), a member of the Papillomaviridae family, is the primary etiological agent of cervical cancer. Here, we report the complete genome sequences of four HPV16 Asian American variants and four European variants, isolated from cervical biopsies and scrapings in India.