Harish Rotti

DNA methylation patterns in luminal breast cancers differ from non-luminal subtypes and can identify relapse risk independent of other clinical variables

The diversity of breast cancers reflects variations in underlying biology and affects the clinical implications for patients. Gene expression studies have identified five major subtypes– Luminal A, Luminal B, basal‐like, ErbB2+ and Normal‐Like. We set out to determine the role of DNA methylation in subtypes by performing genome‐wide scans of CpG methylation in breast cancer samples with known expression‐based subtypes. Unsupervised hierarchical clustering using a set of most varying loci clustered the tumors into a Luminal A majority (82%) cluster, Basal‐like/ErbB2+ majority (86%) cluster and a non‐specific cluster with samples that were also inconclusive in their expression‐based subtype correlations. Contributing methylation loci were both gene associated loci (30%) and non‐gene associated (70%), suggesting subtype dependant genome‐wide alterations in the methylation landscape. The methylation patterns of significant differentially methylated genes in luminal A tumors are similar to those identified in CD24 + luminal epithelial cells and the patterns in basal‐like tumors similar to CD44 + breast progenitor cells. CpG islands in the HOXA cluster and other homeobox (IRX2, DLX2, NKX2‐2) genes were significantly more methylated in Luminal A tumors. A significant number of genes (2853, p < 0.05) exhibited expression–methylation correlation, implying possible functional effects of methylation on gene expression. Furthermore, analysis of these tumors by using follow‐up survival data identified differential methylation of islands proximal to genes involved in Cell Cycle and Proliferation (Ki‐67, UBE2C, KIF2C, HDAC4), angiogenesis (VEGF, BTG1, KLF5), cell fate commitment (SPRY1, OLIG2, LHX2 and LHX5) as having prognostic value independent of subtypes and other clinical factors.

Genome-wide analysis correlates Ayurveda Prakriti

The practice of Ayurveda, the traditional medicine of India, is based on the concept of three major constitutional types (Vata, Pitta and Kapha) defined as “Prakriti”. To the best of our knowledge, no study has convincingly correlated genomic variations with the classification of Prakriti. In the present study, we performed genome-wide SNP (single nucleotide polymorphism) analysis (Affymetrix, 6.0) of 262 well-classified male individuals (after screening 3416 subjects) belonging to three Prakritis. We found 52 SNPs (p ≤ 1 × 10−5) were significantly different between Prakritis, without any confounding effect of stratification, after 106 permutations. Principal component analysis (PCA) of these SNPs classified 262 individuals into their respective groups (Vata, Pitta and Kapha) irrespective of their ancestry, which represent its power in categorization. We further validated our finding with 297 Indian population samples with known ancestry. Subsequently, we found that PGM1 correlates with phenotype of Pitta as described in the ancient text of Caraka Samhita, suggesting that the phenotypic classification of India’s traditional medicine has a genetic basis; and its Prakriti-based practice in vogue for many centuries resonates with personalized medicine.

DNA methylation analysis of phenotype specific stratified Indian population

BackgroundDNA methylation and its perturbations are an established attribute to a wide spectrum of phenotypic variations and disease conditions. Indian traditional system practices personalized medicine through indigenous concept of distinctly descriptive physiological, psychological and anatomical features known as prakriti. Here we attempted to establish DNA methylation differences in these three prakriti phenotypes.MethodsFollowing structured and objective measurement of 3416 subjects, whole blood DNA of 147 healthy male individuals belonging to defined prakriti (Vata, Pitta and Kapha) between the age group of 20-30years were subjected to methylated DNA immunoprecipitation (MeDIP) and microarray analysis. After data analysis, prakriti specific signatures were validated through bisulfite DNA sequencing.ResultsDifferentially methylated regions in CpG islands and shores were significantly enriched in promoters/UTRs and gene body regions. Phenotypes characterized by higher metabolism (Pitta prakriti) in individuals showed distinct promoter (34) and gene body methylation (204), followed by Vata prakriti which correlates to motion showed DNA methylation in 52 promoters and 139 CpG islands and finally individuals with structural attributes (Kapha prakriti) with 23 and 19 promoters and CpG islands respectively. Bisulfite DNA sequencing of prakriti specific multiple CpG sites in promoters and 5′-UTR such as; LHX1 (Vata prakriti), SOX11 (Pitta prakriti) and CDH22 (Kapha prakriti) were validated. Kapha prakriti specific CDH22 5′-UTR CpG methylation was also found to be associated with higher body mass index (BMI).ConclusionDifferential DNA methylation signatures in three distinct prakriti phenotypes demonstrate the epigenetic basis of Indian traditional human classification which may have relevance to personalized medicine.

Determinants of Prakriti, the Human Constitution Types of Indian Traditional Medicine and its Correlation with Contemporary Science

Background: Constitutional type of an individual or prakriti is the basic clinical denominator in Ayurveda, which defines physical, physiological, and psychological traits of an individual and is the template for individualized diet, lifestyle counseling, and treatment. The large number of phenotype description by prakriti determination is based on the knowledge and experience of the assessor, and hence subject to inherent variations and interpretations. Objective: In this study we have attempted to relate dominant prakriti attribute to body mass index (BMI) of individuals by assessing an acceptable tool to provide the quantitative measure to the currently qualitative ayurvedic prakriti determination. Materials and Methods: The study is cross sectional, multicentered, and prakriti assessment of a total of 3416 subjects was undertaken. Healthy male, nonsmoking, nonalcoholic volunteers between the age group of 20-30 were screened for their prakriti after obtaining written consent to participate in the study. The prakriti was determined on the phenotype description of ayurvedic texts and simultaneously by the use of a computer-aided prakriti assessment tool. Kappa statistical analysis was employed to validate the prakriti assessment and Chi-square, Cramer′s V test to determine the relatedness in the dominant prakriti to various attributes. Results: We found 80% concordance between ayurvedic physician and software in predicting the prakriti of an individual. The kappa value of 0.77 showed moderate agreement in prakriti assessment. We observed a significant correlations of dominant prakriti to place of birth and BMI with Chi-square, P < 0.01 (Cramer′s V-value of 0.156 and 0.368, respectively). Conclusion: The present study attempts to integrate knowledge of traditional ayurvedic concepts with the contemporary science. We have demonstrated analysis of prakriti classification and its association with BMI and place of birth with the implications to one of the ways for human classification.

Copy number variations are progressively associated with the pathogenesis of colorectal cancer in ulcerative colitis.

AIM To evaluate the association of known copy number variations (CNVs) in ulcerative colitis (UC) progressing to colorectal cancer. METHODS Microsatellite instability analysis using the National Cancer Institutes panel of markers, and CNV association studies using Agilent 2 × 105 k arrays were done in tissue samples from four patient groups with UC: those at low risk (LR) or high risk of developing colorectal cancer, those with premalignant dysplastic lesions, and those with colitis-associated colorectal cancer (CAC). DNA from tissue samples of these groups were independently hybridized on arrays and analyzed. The data obtained were further subjected to downstream bioinformatics enrichment analysis to examine the correlation with CAC progression. RESULTS Microarray analysis highlighted a progressive increase in the total number of CNVs [LR (n = 178) vs CAC (n = 958), 5.3-fold], gains and losses [LR (n = 37 and 141) vs CAC (n = 495 and 463), 13.4- and 3.3-fold, respectively], size [LR (964.2 kb) vs CAC (10540 kb), 10.9-fold] and the number of genes in such regions [LR (n = 119) vs CAC (n = 455), 3.8-fold]. Chromosome-wise analysis of CNVs also showed an increase in the number of CNVs across each chromosome. There were 38 genes common to all four groups in the study; 13 of these were common to cancer genes from the Genetic Disease Association dataset. The gene set enrichment analysis and ontology analysis highlighted many cancer-associated genes. All the samples in the different groups were microsatellite stable. CONCLUSION Increasing numbers of CNVs are associated with the progression of UC to CAC, and warrant further detailed exploration.

Immunophenotyping of normal individuals classified on the basis of human dosha prakriti.

Background:Human variations related to immune response and disease susceptibility is well-documented in Ayurveda. Prakriti (body constitution) is the basic constitution of an individual established at the time of birth and distinguishes variations, into three broad phenotype categories such as vata, pitta and kapha. Variation in immune response is often attributed to and measured from the difference in cluster differentiation (CD) markers expressed in lymphocytes. Currently, there are no reports available on the expression of CD markers related to prakriti. Objective: This is a pilot study performed to evaluate a panel of lymphocyte subset CD markers in dominant prakriti individuals. Materials and Methods: Immunophenotyping was carried out using whole blood from a total of healthy 222 subjects, who are grouped into kapha (n = 95), pitta (n = 57) and vata (n = 70) prakritis. CD markers such as CD3, CD4, CD8, CD14, CD25, CD56, CD69, CD71 and HLA-DR were analyzed using flow cytometry method. Differences between groups were analyzed using one-way ANOVA or Kruskal-Wallis analysis of variance (ANOVA) and multiple comparisons between groups were performed by Bonferroni or Mann-Whitney U test with corrections for type I error respectively. Significance was evaluated by ANOVA and Pearson′s correlation. Results: We observed a significant difference (P < 0.05) in the expression of CD markers such as CD14 (monocytes), CD25 (activated B cells) and CD56 (Natural killer cells) between different prakriti groups. CD25 and CD56 expression was significantly higher in kapha prakriti samples than other prakriti groups. Similarly, slightly higher levels of CD14 were observed in pitta prakriti samples. Conclusion: Significant difference in the expression of CD14, CD25 and CD56 markers between three different prakriti is demonstrated. The increased level of CD25 and CD56 in kapha prakriti may indicate ability to elicit better immune response, which is in conformity with textual references in Ayurveda.

Aberrant gene-specific DNA methylation signature analysis in cervical cancer

Multicomponent molecular modifications such as DNA methylation may offer sensitive and specific cervical intraepithelial neoplasia and cervical cancer biomarkers. In this study, we tested cervical tissues at various stages of tumor progression for 5-methylcytosine and 5-hydroxymethylcytosine levels and also DNA promoter methylation profile of a panel of genes for its diagnostic potential. In total, 5-methylcytosine, 5-hydroxymethylcytosine, and promoter methylation of 33 genes were evaluated by reversed-phase high-performance liquid chromatography, enzyme-linked immunosorbent assay based technique, and bisulfate-based next generation sequencing. The 5-methylcytosine and 5-hydroxymethylcytosine contents were significantly reduced in squamous cell carcinoma and receiver operating characteristic curve analysis showed a significant difference in (1) 5-methylcytosine between normal and squamous cell carcinoma tissues (area under the curve = 0.946) and (2) 5-hydroxymethylcytosine levels among normal, squamous intraepithelial lesions and squamous cell carcinoma. Analyses of our next generation sequencing results and data from five independent published studies consisting of 191 normal, 10 low-grade squamous intraepithelial lesions, 21 high-grade squamous intraepithelial lesions, and 335 malignant tissues identified a panel of nine genes (ARHGAP6, DAPK1, HAND2, NKX2-2, NNAT, PCDH10, PROX1, PITX2, and RAB6C) which could effectively discriminate among the various groups with sensitivity and specificity of 80%–100% (p < 0.05). Furthermore, 12 gene promoters (ARHGAP6, HAND2, LHX9, HEY2, NKX2-2, PCDH10, PITX2, PROX1, TBX3, IKBKG, RAB6C, and DAPK1) were also methylated in one or more of the cervical cancer cell lines tested. The global and gene-specific methylation of the panel of genes identified in our study may serve as useful biomarkers for the early detection and clinical management of cervical cancer.

A novel gene THSD7A is associated with obesity.

Body mass index (BMI) is a non-invasive measurement of obesity. It is commonly used for assessing adiposity and obesity-related risk prediction. Genetic differences between ethnic groups are important factors, which contribute to the variation in phenotypic effects. India inhabited by the first out-of-Africa human population and the contemporary Indian populations are admixture of two ancestral populations; ancestral north Indians (ANI) and ancestral south Indians (ASI). Although ANI are related to Europeans, ASI are not related to any group outside Indian-subcontinent. Hence, we expect novel genetic loci associated with BMI. In association analysis, we found eight genic SNPs in extreme of distribution (P⩽3.75 × 10−5), of which WWOX has already been reported to be associated with obesity-related traits hence excluded from further study. Interestingly, we observed rs1526538, an intronic SNP of THSD7A; a novel gene significantly associated with obesity (P=2.88 × 10−5, 8.922 × 10−6 and 2.504 × 10−9 in discovery, replication and combined stages, respectively). THSD7A is neural N-glycoprotein, which promotes angiogenesis and it is well known that angiogenesis modulates obesity, adipose metabolism and insulin sensitivity, hence our result find a correlation. This information can be used for drug target, early diagnosis of obesity and treatment.

Comprehensive DNA copy number profile and BAC library construction of an Indian individual

Bacterial artificial chromosomes (BACs) are used in genomic variation studies due to their capacity to carry a large insert, their high clonal stability, low rate of chimerism and ease of manipulation. In the present study, an attempt was made to create the first genomic BAC library of an anonymous Indian male (IMBL4) consisting of 100,224 clones covering the human genome more than three times. Restriction mapping of 255 BAC clones by pulse field gel electrophoresis confirmed an average insert size of 120 kb. The library was screened by PCR using SHANK3 (SH3 and multiple ankyrin repeat domains 3) and OLFM3 (olfactomedin 3) specific primers. A selection of clones was analyzed by fluorescent in situ hybridization (FISH) and sequencing. Fine mapping of copy number variable regions by array based comparative genomic hybridization identified 467 CNVRs in the IMBL4 genome. The IMBL4 BAC library represents the first cataloged Indian genome resource for applications in basic and clinical research.

Epigenetic regulation of double c2 like domain beta (Doc2b) in cervical cancer.

Associations of genetic changes and aneuploidy with tumor growth are traditionally attributed to alterations in DNA sequence manifested as mutations, deletions and amplifications. Inactive tumor suppressor genes could serve as drivers of tumor progression due to not only altered or lack of protein function but may also contribute to phenotypic changes that may provide distinct growth advantage in a hostile environment in the host. Human variation is also due to epigenetic alterations and heritable change that leads to altered gene expression; the functional consequence of which may contribute to definitive trait. A number of key regulatory genes associated with epigenetic silencing due to DNA methylation in cervical cancer have been reported. Elucidation of differentially methylated genes may identify new targets and further strengthen our understanding of molecular mechanism governing pathogenesis of cervical cancer. Thus, to identify DNA methylation regulated genes in cervical cancer, we have employed DMH based microarray experiments in pre-malignant and malignant cervical sample. Microarray data analysis and validation using bisulfite genomic sequencing lead to the identification of several CpG island as altered during cervical carcinogenesis and showed the potential for early screening of cervical cancer. One of the candidate gene identified was Double C2 like Domain beta (DOC2B), a key calcium regulator protein whose alteration has never been linked to cancer. We provide evidence that DOC2B is depressed in cervical cancer due to promoter hypermethylation and act as a novel tumor suppressor gene by regulating multiple pathways in cervical cancer.