Cancer cell plasticity: from cellular, molecular, and genetic mechanisms to tumor heterogeneity and drug resistance.

Cancer is a complex disease displaying a variety of cell states and phenotypes. This diversity, known as cancer cell plasticity, confers cancer cells the ability to change in response to their environment, leading to increased tumor diversity and drug resistance. This review explores the intricate landscape of cancer cell plasticity, offering a deep dive into the cellular, molecular, and genetic mechanisms that underlie this phenomenon. Cancer cell plasticity is intertwined with processes such as epithelial-mesenchymal transition and the acquisition of stem cell-like features. These processes are pivotal in the development and progression of tumors, contributing to the multifaceted nature of cancer and the challenges associated with its treatment. Despite significant advancements in targeted therapies, cancer cell adaptability and subsequent therapy-induced resistance remain persistent obstacles in achieving consistent, successful cancer treatment outcomes. Our review delves into the array of mechanisms cancer cells exploit to maintain plasticity, including epigenetic modifications, alterations in signaling pathways, and environmental interactions. We discuss strategies to counteract cancer cell plasticity, such as targeting specific cellular pathways and employing combination therapies. These strategies promise to enhance the efficacy of cancer treatments and mitigate therapy resistance. In conclusion, this review offers a holistic, detailed exploration of cancer cell plasticity, aiming to bolster the understanding and approach toward tackling the challenges posed by tumor heterogeneity and drug resistance. As articulated in this review, the delineation of cellular, molecular, and genetic mechanisms underlying tumor heterogeneity and drug resistance seeks to contribute substantially to the progress in cancer therapeutics and the advancement of precision medicine, ultimately enhancing the prospects for effective cancer treatment and patient outcomes.

Associations between telomere attrition, genetic variants in telomere maintenance genes, and non-small cell lung cancer risk in the Jammu and Kashmir population of North India.

BACKGROUND: Telomeres are repetitive DNA sequences located at the ends of chromosomes, playing a vital role in maintaining chromosomal integrity and stability. Dysregulation of telomeres has been implicated in the development of various cancers, including non-small cell lung cancer (NSCLC), which is the most common type of lung cancer. Genetic variations within telomere maintenance genes may influence the risk of developing NSCLC. The present study aimed to evaluate the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India, and to investigate the relationship between telomere length and NSCLC risk. METHODS: We employed the cost-effective and high-throughput MassARRAY MALDI-TOF platform to assess the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India. Additionally, we used TaqMan genotyping to validate our results. Furthermore, we investigated telomere length variation and its relation to NSCLC risk in the same population using dual-labeled fluorescence-based qPCR. RESULTS: Our findings revealed significant associations of TERT rs10069690 and POT1 rs10228682 with NSCLC risk (adjusted p-values = 0.019 and 0.002, respectively), while TERF2 rs251796 and rs2975843 showed no significant associations. The TaqMan genotyping validation further substantiated the associations of TERT rs10069690 and rs2242652 with NSCLC risk (adjusted p-values = 0.02 and 0.003, respectively). Our results also demonstrated significantly shorter telomere lengths in NSCLC patients compared to controls (p = 0.0004). CONCLUSION: This study highlights the crucial interplay between genetic variation in telomere maintenance genes, telomere attrition, and NSCLC risk in the Jammu and Kashmir population of North India. Our findings suggest that TERT and POT1 gene variants, along with telomere length, may serve as potential biomarkers and therapeutic targets for NSCLC in this population. Further research is warranted to elucidate the underlying mechanisms and to explore the potential clinical applications of these findings.

Association of newly identified genetic variant rs2853677 of TERT with non-small cell lung cancer and leukemia in population of Jammu and Kashmir, India.

BACKGROUND: Telomere genetics has recently been emerged as an important field in molecular oncology. Various genome-wide association studies in different population groups have revealed that polymorphisms in Telomere maintenance gene (TERT) gene located on 5p15.33 is associated with susceptibility to leukemia and lung cancer risk. However, association of TERT with leukemia and lung cancer risk in north Indian population groups is still unknown. This study observed the association between genetic variant rs2853677 of TERT and leukemia and lung cancer in the state of Jammu and Kashmir, India. METHODS: A total of 781 subjects, out of which 381 cases (203 leukemic patients and 178 non-small cell lung cancer patients NSCLC) and 400 healthy controls were recruited for the study. Genetic variant rs2853677of TERT was detected using the real-time and Taqman Chemistry. Hardy-Weinberg Equilibrium was assessed using the chi square test. The allele and genotype- specific risks were estimated as odds ratio with 95% confidence interval. RESULTS: We observed that variant rs2853677 was strongly associated with lung cancer and leukemia risk with an odds ratio (OR) =1.8 (1.03-3.2 at 95% CI); p value (adjusted) = 0.03; odds ratio (OR) =2.9 (1.4-5.5.at 95% CI); p value (adjusted) = 0.002, respectively. CONCLUSION: The results of this study suggested that rs2853677 of TERT signifies association in multiple cancers and suggests that it can become potential marker for diagnosis of non-small cell lung cancer and leukemia. The study will provide an insight in understanding the genetic etiology and highlights the role of telomere-associated pathways in non-small cell lung cancer and leukemia. However, it would be quite interesting to explore the contribution of this variant in other cancers as well.

Innovative in Silico Approaches for Characterization of Genes and Proteins.

Bioinformatics is an amalgamation of biology, mathematics and computer science. It is a science which gathers the information from biology in terms of molecules and applies the informatic techniques to the gathered information for understanding and organizing the data in a useful manner. With the help of bioinformatics, the experimental data generated is stored in several databases available online like nucleotide database, protein databases, GENBANK and others. The data stored in these databases is used as reference for experimental evaluation and validation. Till now several online tools have been developed to analyze the genomic, transcriptomic, proteomics, epigenomics and metabolomics data. Some of them include Human Splicing Finder (HSF), Exonic Splicing Enhancer Mutation taster, and others. A number of SNPs are observed in the non-coding, intronic regions and play a role in the regulation of genes, which may or may not directly impose an effect on the protein expression. Many mutations are thought to influence the splicing mechanism by affecting the existing splice sites or creating a new sites. To predict the effect of mutation (SNP) on splicing mechanism/signal, HSF was developed. Thus, the tool is helpful in predicting the effect of mutations on splicing signals and can provide data even for better understanding of the intronic mutations that can be further validated experimentally. Additionally, rapid advancement in proteomics have steered researchers to organize the study of protein structure, function, relationships, and dynamics in space and time. Thus the effective integration of all of these technological interventions will eventually lead to steering up of next-generation systems biology, which will provide valuable biological insights in the field of research, diagnostic, therapeutic and development of personalized medicine.

Dual labeled fluorescence probe based qPCR assay to measure the telomere length.

Telomeres are highly repetitive regions capping the chromosomes and composed of multiple units of hexa-nucleotides, TTAGGG, making their quantification difficult. Most of the methods developed to estimate telomeres are extensively cumbersome or expensive. The quantitative polymerase chain reaction (qPCR) based assay is relatively easy and cheaper method that applies SyBr Green dye chemistry to measure telomere length. SyBr Green dye fluoresces after intercalation into the double stranded DNA (dsDNA), thus detection of unspecific products has been a limitation as it may affect quantitation of telomeres. To overcome this limitation of SyBr Green dye, we developed a dual labeled fluorescence probe based quantitative polymerase chain reaction (qPCR) to measure the telomere length. This highly efficient, yet cost effective and easy method, utilizes a probe that targets primarily the telomeric DNA and this increases accuracy of an existing qPCR method.

Genetic evaluation of the variants using MassARRAY in non-small cell lung cancer among North Indians.

Lung cancer is genetically diverse and a major health burden. Non-small cell lung cancer (NSCLC) accounts for 80% of total lung cancer cases and 20% cases are Small cell lung cancer (SCLC). The present case-control association study focused on the cost effective high throughput genotyping using Agena MassARRAY matrix-assisted laser desorption/ionization-time of flight, mass spectrometry (MALDI-TOF) platform to analyze the genetic association of candidate genetic variants. We performed multiplex PCR and genotyped twelve single nucleotide polymorphisms (SNPs) in 723 samples (162 NSCLC cases and 592 healthy controls). These genetic variants were selected from literature for their association with various cancers worldwide and this is the first study from the region to examine these critically important genetic variants. With prospective case-control association study design, twelve variants from ten genes were evaluated. Amongst these six variants, TCF21 (rs12190287), ERCC1 (rs2298881, 11615), ERCC5 (rs751402), ARNTL (rs4757151), BRIP1 (rs4986764) showed significant association with NSCLC risk (p ≤ 0.003) in Jammu and Kashmir population. In-silico findings of these genetic variants showed remarkable functional roles that needs in-vitro validations. It is further anticipated that such case control studies will help us in understanding the missing heritability of non-small cell lung cancer.

Telomere Maintenance Genes are associated with Type 2 Diabetes Susceptibility in Northwest Indian Population Group.

Telomere length attrition has been implicated in various complex disorders including Type 2 Diabetes (T2D). However, very few candidate gene association studies have been carried out worldwide targeting telomere maintenance genes. In the present study, variants in various critical telomere maintenance pathway genes for T2D susceptibility in Northwest Indian population were explored. With case-control candidate gene association study design, twelve variants from seven telomere maintenance genes were evaluated. Amongst these five variants, rs9419958 (OBFC1), rs4783704 (TERF2), rs16847897 (TERC/LRRC31), rs10936599 (TERC/MYNN), and rs74019828 (CSNK2A2) showed significant association with T2D (at p-value ≤ 0.003, threshold set after Bonferroni correction) in the studied population. In silico analyses of these variants indicated interesting functional roles that warrant experimental validations. Findings showed that variants in telomere maintenance genes are associated with pathogenesis of T2D in Northwest Indian population. We anticipate further, such candidate gene association studies in other Indian populations and worldwide would contribute in understanding the missing heritability of T2D.

Genetic variant rs2494938 of LRFN2 gene is associated with non-small cell lung cancer risk in North-Indian population.

Various Genome-wide association studies (GWAS) have reported the association of variant rs2494938 with lung cancer. However, genetic association of LRFN2 genetic variation with non-small cell lung cancer (NSCLC) in North Indian population remained unexplored. We conducted a case-control association study using TaqMan-based chemistry in which a total of 619 individuals, 189 NSCLC cases and 430 controls, were genotyped to explore the association of rs2494938 genetic variant of the LRFN2 gene with NSCLC patients from North India. The allele 'G' (risk allele) of the genetic variant rs2494938 was significantly associated with the NSCLC [OR = 1.51 (1.18-1.93 at 95% CI); p value = 0.0009]. Genetic association was also explored by applying different genetic models (Dominant, Additive). These results suggest that rs2494938 polymorphism of the LRFN2 gene is a risk factor in the North Indian populations to develop NSCLC. The LD (Linkage Disequilibrium) plot demonstrates the variant and its LD SNPs (r 2 > 0.8) and the variant has direct regulatory effect, which could affect the overall physiology of the gene. These findings could be used as diagnostic and prognostic markers in clinical studies of lung cancer patients in North Indian population groups. The present study also provides an important evidence on the genetic etiology of NSCLC in North Indian populations and further expounds GWAS findings on the role of LRFN2 in lung cancer risk. This study provides the holistic view about the non-small cell lung cancer in Jammu and Kashmir, North Indian population and it can be a hallmark of cancer if verified on a very large sample size (cohort).

Genetic variant rs10937405 of TP63 and susceptibility to lung cancer risk in north Indian population.

Several studies including genomewide association studies (GWASs) in diverse ethnic populations have reported a significant association of genetic variant rs10937405 of TP63 with nonsmall cell lung cancer (NSCLC). However, no data are available from any Indian population on the association of this variant with NSCLC. Using TaqMan genotyping chemistry, we conducted a case-control study involving 190 NSCLC cases and 400 ethnic, age-matched controls to explore the association of rs10937405 genetic variant with NSCLC in patients from north India. Our data support that the rs10937405 variant is also significantly associated with the NSCLC and is a risk factor in the north Indian populations to develop NSCLC. However, unlike most other studies, the wild-type allele T appears to be the risk allele, as its frequency was significantly higher in the cases than controls (0.439 in cases versus 0.383 in controls. OR=1.95 (1.23-3.09 at 95% CI); P value (adjusted)= 0.004). Genetic association was also observed by applying different genetic models. The present study provides important information of the genetic aetiology of NSCLC and strengthens GWAS findings, highlighting the role of TP63 in lung cancer risk.

Replication of newly identified type 2 diabetes susceptible loci in Northwest Indian population.

OBJECTIVE: To replicate the association of newly identified variants of TMEM163 (transmembrane protein 163) and COBLL1 (cordon-bleu protein-like 1) with type 2 diabetes (T2D) in Northwest Indian population. METHODS: We performed a replication study of variants rs998451 and rs6723108 of gene TMEM163 and rs7607980 of gene COBLL1. The variations were genotyped using Taqman allele discrimination assay in 1209 Northwest Indians (651 T2D cases and 558 controls). The association of each SNP with the disease was evaluated using logistic regression. RESULTS: All the three SNPs examined in this study did not show any significant association with T2D. For rs998451 and rs6723108 of TMEM163 the observed odds ratios were 0.71 with a 95% CI of 0.28-1.84 (p=0.484) and 1.80 with a 95% CI of 0.74-4.40 (p=0.196), respectively. For rs7607980 the estimated odds ratio was 1.01 with 95% CI of 0.70-1.44 (p=0.946). CONCLUSION: We conclude that lack of association could be because of population structure of Indian Population that is conglomeration of various ethnic groups. For a conclusive association study of T2D in India, it is critical that such studies are carried out among endogamous ethnic groups rather than conventional practice of pooling samples based on Geographical/regional or linguist affiliations like Asian Indian, North or South Indian etc.

Role of telomeres and associated maintenance genes in Type 2 Diabetes Mellitus: A review.

Type 2 Diabetes Mellitus (T2DM), a multifactorial complex disorder, is emerging as a major cause of morbidity, mortality and socio-economic burden across the world. Despite huge efforts in understanding genetics of T2DM, only ∼10% of the genetic factors have been identified so far. Telomere attrition, a natural phenomenon has recently emerged in understanding the pathophysiology of T2DM. It has been indicated that Telomeres and associated pathways might be the critical components in the disease etiology, though the mechanism(s) involved are not clear. Recent Genome Wide (GWAS) and Candidate Gene Case-Control Association Studies have also indicated an association of Telomere and associated pathways related genes with T2DM. Single Nucleotide Polymorphisms (SNPs) in the telomere maintenance genes: TERT, TERC, TNKS, CSNK2A2, TEP1, ACD, TRF1 and TRF2, have shown strong association with telomere attrition in T2DM and its pathophysiology, in these studies. However, the assessment has been made within limited ethnicities (Caucasians, Han Chinese cohort and Punjabi Sikhs from South Asia), warranting the study of such associations in different ethnic groups. Here, we propose the possible mechanisms, in the light of existing knowledge, to understand the association of T2DM with telomeres and associated pathways.