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62 result(s) for "Pillai, M Radhakrishna"
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Evaluation of immune response to single dose of quadrivalent HPV vaccine at 10-year post-vaccination
The recent World Health Organization recommendation supporting single-dose of HPV vaccine will significantly reduce programmatic cost, mitigate the supply shortage, and simplify logistics, thus allowing more low- and middle-income countries to introduce the vaccine. From a programmatic perspective the durability of protection offered by a single-dose will be a key consideration. The primary objectives of the present study were to determine whether recipients of a single-dose of quadrivalent HPV vaccine had sustained immune response against targeted HPV types (HPV 6,11,16,18) at 10 years post-vaccination and whether this response was superior to the natural antibody titres observed in unvaccinated women. Participants received at age 10–18 years either one, two or three doses of the quadrivalent HPV vaccine. Serology samples were obtained at different timepoints up to 10 years after vaccination from a convenience sample of vaccinated participants and from age-matched unvaccinated women at one timepoint. The evolution of the binding and neutralizing antibody response was presented by dose received. 10-year durability of immune responses induced by a single-dose was compared to that after three doses of the vaccine and in unvaccinated married women. The dynamics of antibody response among the single-dose recipients observed over 120 months show stabilized levels 18 months after vaccination for all four HPV types. Although the HPV type-specific (binding or neutralizing) antibody titres after a single-dose were significantly inferior to those after three doses of the vaccine (lower bounds of GMT ratios < 0.5), they were all significantly higher than those observed in unvaccinated women following natural infections (GMT ratios: 2.05 to 4.04-fold higher). The results correlate well with the high vaccine efficacy of single-dose against persistent HPV 16/18 infections reported by us earlier at 10-years post-vaccination. Our study demonstrates the high and durable immune response in single-dose recipients of HPV vaccine at 10-years post vaccination.
Coordinated dysregulation of cancer progression by the HER family and p21-activated kinases
Most epithelial cancer types are polygenic in nature and are driven by coordinated dysregulation of multiple regulatory pathways, genes, and protein modifications. The process of coordinated regulation of cancer promoting pathways in response to extrinsic and intrinsic signals facilitates the dysregulation of several pathways with complementary functions, contributing to the hallmarks of cancer. Dysregulation and hyperactivation of cell surface human epidermal growth factor receptors (HERs) and cytoskeleton remodeling by p21-activated kinases (PAKs) are two prominent interconnected aspects of oncogenesis. We briefly discuss the discoveries and significant advances in the area of coordinated regulation of HERs and PAKs in the development and progression of breast and other epithelial cancers. We also discuss how initial studies involving heregulin signaling via HER3-HER2 axis and HER2-overexpressing breast cancer cells not only discovered a mechanistic role of PAK1 in breast cancer pathobiology but also acted as a bridge in generating a broader cancer research interest in other PAK family members and cancer types and catalyzed establishing the role of PAKs in human cancer, at-large. In addition, growth factor stimulation of the PAK pathway also helped to recognize new facets of PAKs, connecting the PAK pathway to oncogenesis, nuclear signaling, gene expression, mitotic progression, DNA damage response, among other phenotypic responses, and shaped the field of PAK cancer research. Finally, we recount some of the current limitations of HER- and PAK-directed therapeutics in counteracting acquired therapeutic resistance and discuss how cancer’s as a polygenic disease may be best targeted with a polygenic approach.
TALEN based HPV-E7 editing triggers necrotic cell death in cervical cancer cells
Human Papillomavirus E7 and E6 oncoproteins have been considered as suitable candidate anti-viral targets since they cause malignant conversion in cervical cancers. Transcription Activator-Like Effector Nucleases (TALENs) are recent editing tools to knockout genes by inducing double stranded breaks at specific sites in the genome. In here, we have designed specific TALENs to target E7 and analyzed their efficiency in inducing cell death in cervical cancer cells. We found that designed TALENs could yield about 10–12% editing activity as observed from T7E1 and nuclease resistance assays. Down-regulation of E7 and E6 was further evident at the transcript as well as proteins levels indicating that the selected TALENs were effective. TALEN-mediated E7 editing led to cell death as ascertained by cell cycle and Annexin V assays. Annexin profiling suggested that cell death could be due to necrosis as observed by upregulation of necrotic markers such as LDH A, Rip-1, and Cyclophilin A. Necrosis appears to be a better therapeutic response as it could further activate pro-inflammatory cytokines to attract immune cells to eliminate HPV-integrated cells and therefore TALEN editing strategy has the potential to be a promising tool as an adjuvant therapy in cervical cancer along with surgery.
Efficacy of a herbal mouthwash for management of periodontitis and radiation-induced mucositis – A consolidated report of two randomized controlled clinical trials
Oral diseases like periodontitis and mucositis often require home care using topical agents in the form of mouthwashes. Many herbal mouthwashes are found to be beneficial; however lack proper scientific evidence to support their use. Study 1 evaluated clinical efficacy of herbal mouthwash in the management of chronic periodontitis in comparison with chlorhexidine mouthwash. Study 2 aimed at assessment of herbal mouthwash in patients of radiation-induced mucosititis. The novel herbal mouthwash used in the present study wa prepared from extracts of five plants namely Emblica Officinalis, Terminalia chebula, Terminalia bellerica, Glycyrrhiza glabra, and Azadirachta indica. 50 periodontitis patients were randomly allocated to two groups. As per allocation, they were instructed to use either herbal mouthwash or chlorhexidine mouthwash twice daily for two weeks after nonsurgical periodontal therapy. Similarly, patients with radiation-induced mucositis were randomly given herbal mouthwash and soda saline mouthwash. Intergroup and intragroup comparisons of continuous variables were conducted using paired and unpaired t-tests. Categorical variables were compared using the chi-square test. Significant reductions in gingival bleeding, plaque accumulation, and pocket depth were noticed in periodontitis patients in both groups. Patients reported acceptable taste, freshness, and satisfaction after the use of herbal mouthwash. The herbal mouthwash group noticed a significant reduction in the severity of radiation-induced mucositis and analgesic requirements. The intensity of pain, dryness of mouth, oral hygiene, and need for the use of antibiotic and antifungal during radiotherapy was not significant among the groups. The results of this preliminary clinical trial support the use of the tested herbal formulation mouthwash as an adjunct in the treatment of periodontitis as well as radiation-induced mucositis. For Study 1: CTRI/2019/10/021574, Study 2: CTRI/2020/04/024851.
Frequency and clinical significance of human papilloma virus in oral cancer - A study from Kerala
Abstract Background: Oral cancer is a major health problem in India. Recently an increase in the oral cancer incidence among young individuals without any habits was observed, which may be due to Human Papilloma Virus (HPV). However, information on the prevalence of HPV in oral cancer in India is sparse. This study aims to document the frequency of HPV16 infection in oral squamous cell carcinoma (SCC) and to study its correlation with treatment outcome. Methods: Paraffin-embedded tissue blocks of 183 patients with SCC of the oral cavity were studied. HPV16 prevalence was detected by a polymerase chain reaction and expression of p16INK4a was analyzed by immunohistochemistry. This was correlated with clinical outcomes. Results: The prevalence of HPV 16 was 6.6% and all were carcinoma tongue. All HPV-positive patients showed intense expression of p16INK4a. The five-year overall survival (OS) and disease-free survival (DFS) for HPV positive patients were higher compared to HPV negative patients (100% versus 74.5% and 100% versus 70.8% respectively). The five-year OS and DFS for patients with p16INK4a intense expression were also higher compared to p16INK4a weak expression (91.2% versus 57.4% and 82% versus 22.5% respectively). Five-year OS and DFS of patients with HPV16 positivity and p16INK4a intense expression were significantly higher than patients with HPV negative and p16INK4a weak expression (100% versus 54.7% and 100% versus 22.5% respectively). Conclusion: The frequency of HPV16 positivity in oral cancer was low in this study with a site predilection to the oral tongue. p16INK4a expression did not correlate with HPV status. A better treatment outcome was observed in HPV-positive cancers. We also observed better treatment outcomes in patients with p16INK4A overexpression irrespective of HPV status.
Side Population Cells as Prototype of Chemoresistant, Tumor-Initiating Cells
Classically, isolation of CSCs from tumors exploits the detection of cell surface markers associated with normal stem cells. Invariable expression of these cell surface markers in almost all proliferating tumor cells that albeit impart specific functionality, the universality, and clinical credibility of CSC phenotype based on markers is still dubious. Side Population (SP) cells, as defined by Hoechst dye exclusion in flow cytometry, have been identified in many solid tumors and cell lines and the SP phenotype can be considered as an enriched source of stem cells as well as an alternative source for the isolation of cancer stem cells especially when molecular markers for stem cells are unknown. SP cells may be responsible for the maintenance and propagation of tumors and the proportion of SP cells may be a predictor of patient outcome. Several of these markers used in cell sorting have emerged as prognostic markers of disease progression though it is seen that the development of new CSC-targeted strategies is often hindered by poor understanding of their regulatory networks and functions. This review intends to appraise the experimental progress towards enhanced isolation and drug screening based on property of acquired chemoresistance of cancer stem cells.
Bis(3,5-diiodo-2,4,6-trihydroxyphenyl)squaraine photodynamic therapy disrupts redox homeostasis and induce mitochondria-mediated apoptosis in human breast cancer cells
Photodynamic therapy (PDT) is a clinically established and highly evolving treatment modality for cancer. PDT utilizes a light responsive drug called photosensitizer that selectively destroys tumor cells upon light irradiation. Squaraines are a class of dyes possessing all favorable characteristics of a photosensitizer and have been considered to be a potent candidate for next generation PDT. In this study we chose an iodo derivative of squaraine called diiodo-squaraine (bis(3, 5-diiodo-2,4,6-trihydroxyphenyl)squaraine) which has been reported for its tumor specificity but least studied for its cellular and molecular functions. Our studies revealed that the iodo derivative of squaraine possess maximum photodynamic activity in human breast cancer cells MDA- MB- 231 and had very little cytotoxicity in normal breast cells MCF-10A. We analyzed its pro and anti-apoptotic events initiated by oxidative stress exploring a proteomic approach and delineated other critical molecular pathways and key proteins involved in regulating the complex network of cellular response upon PDT. Our study showed that, diiodo- squaraines predominantly accumulate in mitochondria and induce mitochondria-mediated apoptosis. Our study also reveals the novel mechanistic role of diiodo-squaraines to induce oxidative stress there by activating both protective and death inducing pathways post PDT.
Acquisition, prevalence and clearance of type-specific human papillomavirus infections in young sexually active Indian women: A community-based multicentric cohort study
In context of the ongoing multi-centric HPV vaccine study in India, unvaccinated married women (N = 1484) aged 18–23 years were recruited in 2012–2015 as age-matched controls to the vaccinated women and followed up yearly. We assess type-specific prevalence, natural history and potential determinants of human papillomavirus (HPV) infection in these unvaccinated women. Cervical samples were collected yearly for at least four consecutive years. A Multiplex Type-Specific E7-Based polymerase chain reaction assay was used to detect 21 HPV types. HPV prevalence was 36.4% during 6 years. Most common HPV types were 16 (6.5%) and 31 (6.1%). Highest persistence were observed for HPV 35 (62.5%) and 52 (25%). New HPV acquisition rate was 5.6/1000 person-months of observation (PMO), highest for HPV 16 (1.1/1000 PMO). Type-specific clearance rates ranged between 2.9–5.5/100 PMO. HPV 16 and/or 18 infections were 41% (95% CI 4–63%) lower among women with 2-<3 years between marriage and first cervical sample collection compared to those with <2 years. HPV prevalence and acquisition rates in young Indian women were lower than their Western counterparts. HPV 16 infections being most common shows the importance and potential impact of HPV vaccination in India. Women with 2–3 years exposure had reduced risk possibly due to higher infections clearance.
Genome editing of oncogenes with ZFNs and TALENs: caveats in nuclease design
Background Gene knockout technologies involving programmable nucleases have been used to create knockouts in several applications. Gene editing using Zinc-finger nucleases (ZFNs), Transcription activator like effectors (TALEs) and CRISPR/Cas systems has been used to create changes in the genome in order to make it non-functional. In the present study, we have looked into the possibility of using six fingered CompoZr ZFN pair to target the E6 gene of HPV 16 genome. Methods HPV 16 +ve cell lines; SiHa and CaSki were used for experiments. CompoZr ZFNs targeting E6 gene were designed and constructed by Sigma-Aldrich. TALENs targeting E6 and E7 genes were made using TALEN assembly kit. Gene editing was monitored by T7E1 mismatch nuclease and Nuclease resistance assays. Levels of E6 and E7 were further analyzed by RT-PCR, western blot as well as immunoflourescence analyses. To check if there is any interference due to methylation, cell lines were treated with sodium butyrate, and Nocodazole. Results Although ZFN editing activity in yeast based MEL-I assay was high, it yielded very low activity in tumor cell lines; only 6% editing in CaSki and negligible activity in SiHa cell lines. Though editing efficiency was better in CaSki, no significant reduction in E6 protein levels was observed in immunocytochemical analysis. Further, in silico analysis of DNA binding prediction revealed that some of the ZFN modules bound to sequence that did not match the target sequence. Hence, alternate ZFN pairs for E6 and E7 were not synthesized since no further active sites could be identified by in silico analyses. Then we designed TALENs to target E6 and E7 gene. TALENs designed to target E7 gene led to reduction of E7 levels in CaSki and SiHa cervical cancer cell lines. However, TALEN designed to target E6 gene did not yield any editing activity. Conclusions Our study highlights that designed nucleases intended to obtain bulk effect should have a reasonable editing activity which reflects phenotypically as well. Nucleases with low editing efficiency, intended for generation of knockout cell lines nucleases could be obtained by single cell cloning. This could serve as a criterion for designing ZFNs and TALENs.
MTar: a computational microRNA target prediction architecture for human transcriptome
Background MicroRNAs (miRNAs) play an essential task in gene regulatory networks by inhibiting the expression of target mRNAs. As their mRNA targets are genes involved in important cell functions, there is a growing interest in identifying the relationship between miRNAs and their target mRNAs. So, there is now a imperative need to develop a computational method by which we can identify the target mRNAs of existing miRNAs. Here, we proposed an efficient machine learning model to unravel the relationship between miRNAs and their target mRNAs. Results We present a novel computational architecture MTar for miRNA target prediction which reports 94.5% sensitivity and 90.5% specificity. We identified 16 positional, thermodynamic and structural parameters from the wet lab proven miRNA:mRNA pairs and MTar makes use of these parameters for miRNA target identification. It incorporates an Artificial Neural Network (ANN) verifier which is trained by wet lab proven microRNA targets. A number of hitherto unknown targets of many miRNA families were located using MTar. The method identifies all three potential miRNA targets (5' seed-only, 5' dominant, and 3' canonical) whereas the existing solutions focus on 5' complementarities alone. Conclusion MTar, an ANN based architecture for identifying functional regulatory miRNA-mRNA interaction using predicted miRNA targets. The area of target prediction has received a new momentum with the function of a thermodynamic model incorporating target accessibility. This model incorporates sixteen structural, thermodynamic and positional features of residues in miRNA: mRNA pairs were employed to select target candidates. So our novel machine learning architecture, MTar is found to be more comprehensive than the existing methods in predicting miRNA targets, especially human transcritome.