Biswanath Maity

Spectrum and frequency of GJB2, GJB6 and SLC26A4 gene mutations among nonsyndromic hearing loss patients in eastern part of India

Genetically caused nonsyndromic hearing loss is highly heterogeneous. Inspite of this large heterogeneity, mutations in the genes GJB2, GJB6 and SLC26A4 are major contributors. The mutation spectrum of these genes varies among different ethnic groups. Only a handful of studies focused on the altered genetic signature of these genes in different demographic regions of India but never focused on the eastern part of the country. Our study for the first time aimed to characterize the mutation profile of these genes in hearing loss patients of West Bengal state, India. Mutations in GJB2, GJB6 and SLC26A4 genes were screened by bidirectional sequencing from 215 congenital nonsyndromic hearing loss patients. Radiological diagnosis was performed in patients with SLC26A4 mutations by temporal bone CT scan. The study revealed that 4.65% and 6.97% patients had monoallelic and biallelic GJB2 mutations respectively. Six mutations were identified, p.W24X being the most frequent one accounting for 71.05% of the mutated alleles. Mutations in GJB6 including the previously identified deletion mutation (GJB6-D13S1830) were not identified in our study. Further, no patients harbored biallelic mutations in the SLC26A4 gene or the common inner ear malformation Enlarged Vestibular Aqueduct (EVA). The mutation profile of GJB2 in our study is distinct from other parts of India, suggesting that the mutation spectrum of this gene varies with ethnicity and geographical origin. The absence of GJB6 mutations and low frequency of SLC26A4 mutations suggest that additional genetic factors may also contribute to this disease.

Poly(lactic- co -glycolic acid)-loaded nanoparticles of betulinic acid for improved treatment of hepatic cancer: characterization, in vitro and in vivo evaluations

Purpose The application of betulinic acid (B), a potent antineoplastic agent, is limited due to poor bioavailability, short plasma half-life and inappropriate tissue distribution. Thus, we aimed to prepare novel 50:50 poly(lactic-co-glycolic acid) (PLGA)-loaded B nanoparticles (BNP) and to compare its anti-hepatocellular carcinoma (HCC) activity with parent B. Methods BNP were synthesized and characterized using different methods such as scanning electron microscopy (SEM), fourier-transform infrared (FTIR) spectrometry and particle size analyses. Particle size of BNP was optimized through the application of the stabilizer, polyvinyl alcohol (PVA). The anti-HCC response was evaluated through in vitro cell line study using Hep-G2 cells, confocal microscopy, in vivo oral pharmacokinetics and animal studies. Further, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis was conducted to observe the changes in the expression of specific genes. Results Particle size of BNP was optimized through the application of the stabilizer, polyvinyl alcohol. Physicochemical characterization exhibited particle size of 257.1 nm with zeta potential −0.170 mV (optimized batch B, BNP). SEM and FTIR analyses of BNP showed that cylindrical particles of B converted to spherical particles in BNP and there were no interaction between B and used polymers. The release study of optimized BNP was highest (≥80%) than any other formulation. Later, in vitro cell culture analysis using Hep-G2 cells and confocal microscopy studies revealed that BNP had the highest inhibition and penetration properties than parent B. Oral pharmacokinetics studies using albino Wistar rats at single 100 mg dose again exhibited BNP had the higher 50% of plasma concentration (t1/2), a higher maximum plasma concentration (Cmax) and took longer to reach the maximum plasma concentration (Tmax) than parent B. Next, our in vivo study using nitrosodiethyl amine (NDEA)-induced HCC model documented BNP decreased in number of nodules, restored body weight, oxidative stress parameters, liver marker enzymes and histological architecture than parent B. Lastly, qRT-PCR studies further demonstrated that anti-HCC properties of BNP may be due to over expression of antiapoptotic caspases i.e., caspase 3 and 8. Conclusion The prepared BNP showed a better therapeutic response against HCC and could be attributed as future candidate molecule for HCC treatment.

Novel 1,3,4-thiadiazoles inhibit colorectal cancer via blockade of IL-6/COX-2 mediated JAK2/STAT3 signals as evidenced through data-based mathematical modeling

We attempted a preclinical study using DMH-induced CRC rat model to evaluate the antitumor potential of our recently synthesized 1,3,4-thiadiazoles. The molecular insights were confirmed through ELISA, qRT-PCR and western blot analyses. The CRC condition was produced in response to COX-2 and IL-6 induced activation of JAK2/STAT3 which, in turn, was due to the enhanced phosphorylation of JAK2 and STAT3. The treatment with 1,3,4-thiadiazole derivatives (VR24 and VR27) caused the significant blockade of this signaling pathway. The behavior of STAT3 populations in response to IL-6 and COX-2 stimulations was further confirmed through data-based mathematical modeling using the quantitative western blot data. Finally, VR24 and VR27 restored the perturbed metabolites associated to DMH-induced CRC as evidenced through 1H NMR based serum metabolomics. The tumor protecting ability of VR24 and VR27 was found comparable or to some degree better than the marketed chemotherapeutics, 5-flurouracil.

Atypical G protein β5 promotes cardiac oxidative stress, apoptosis, and fibrotic remodeling in response to multiple cancer chemotherapeutics

The clinical use of multiple classes of cancer chemotherapeutics is limited by irreversible, dose-dependent, and sometimes life-threatening cardiotoxicity. Though distinct in their mechanisms of action, doxorubicin, paclitaxel, and 5-FU all induce rapid and robust upregulation of atypical G protein Gβ5 in the myocardium correlating with oxidative stress, myocyte apoptosis, and the accumulation of proinflammatory and profibrotic cytokines. In ventricular cardiac myocytes (VCM), Gβ5 deficiency provided substantial protection against the cytotoxic actions of chemotherapeutics, including reductions in oxidative stress and simultaneous attenuation of ROS-dependent activation of the ATM and CaMKII proapoptotic signaling cascades. In addition, Gβ5 loss allowed for maintenance of Δψm, basal mitochondrial calcium uniporter expression, and mitochondrial Ca2+ levels, effects likely to preserve functional myocyte excitation-contraction coupling. The deleterious effects of Gβ5 are not restricted to VCM, however, as Gβ5 knockdown also reduces chemotherapy-induced release of proinflammatory cytokines (e.g., TNFα), hypertrophic factors (e.g., ANP), and profibrotic factors (e.g., TGFβ1) from both VCM and ventricular cardiac fibroblasts, with the most dramatic reduction occurring in cocultured cells. Our experiments suggest that Gβ5 facilitates the myofibroblast transition, the persistence of which contributes to pathologic remodeling and heart failure. The convergence of Gβ5-mediated, ROS-dependent signaling pathways in both cell types represents a critical etiological factor in the pathogenesis of chemotherapy-induced cardiotoxicity. Indeed, intracardiac injection of Gβ5-targeted shRNA allowed for heart-specific protection against the damaging impact of chronic chemotherapy. Together, our results suggest that inhibition of Gβ5 might represent a novel means to circumvent cardiotoxicity in cancer patients whose treatment regimens include anthracyclines, taxanes, or fluoropyrimidines.Significance: These findings suggest that inhibiting an atypical G-protein might provide a strategy to limit the cardiotoxicity in cancer patients treated with anthracyclines, taxanes, or fluoropyrimidines. Cancer Res; 78(2); 528-41. ©2017 AACR.

Novel Indole-fused benzo-oxazepines (IFBOs) inhibit invasion of hepatocellular carcinoma by targeting IL-6 mediated JAK2/STAT3 oncogenic signals

Inspired by the well-documented tumor protecting ability of paullones, recently, we synthesized novel paullone-like scaffolds, indole-fused benzo-oxazepines (IFBOs), and screened them against hepatocellular carcinoma (HCC) specific Hep-G2 cells. Three of the synthesized compounds significantly attenuated the progression of HCC in vitro. By computational studies, we further discovered that IFBOs exhibited a stable binding complex with the IL-6 receptor. In this context, we investigated in vivo study using the nitrosodiethyl amine (NDEA)-induced HCC model, which strengthened our previous findings by showing the blockade of the IL-6 mediated JAK2/STAT3 oncogenic signaling pathway. Treatment with IFBOs showed remarkable attenuation of cellular proliferation, as evidenced through a decrease in the number of nodules, restoration of body weight, oxidative stress parameters, liver marker enzymes and histological architecture. Interestingly, using a metabolomic approach we further discovered that IFBOs can restore the perturbed metabolic profile associated with the HCC condition to normalcy. Particularly, the efficacy of compound 6a for an anti-HCC response was significantly better than the marketed chemotherapeutic drug, 5-fluorouracil. Altogether, these remarkable findings open up possibilities of developing IFBOs as novel future candidate molecules for plausible alternatives for HCC treatment.

Novel fused oxazepino-indoles (FOIs) attenuate liver carcinogenesis via IL-6/JAK2/STAT3 signaling blockade as evidenced through data-based mathematical modeling

Aims: To potentiate the well‐documented tumor protecting ability of paullones, literatures demand for rational modifications in paullone ring structure and exploration of a precise mechanism underlying their antitumor effects. Thus, recently we synthesized novel paullone‐like scaffold, 5H‐benzo [2, 3][1,4]oxazepino[5,6‐b]indoles, where compounds 13a and 14a attenuated the growth of liver cancer specific Hep‐G2 cells in vitro and formed stable binding complex with IL‐6. Henceforth, we hypothesized that this action is probably due to the blockade of IL‐6 mediated JAK2/STAT3 signaling cascade. Main methods: A preclinical study was conducted using NDEA‐induced HCC rat model by oral administration of FOIs at 10 mg/kg dose for 15 days. The molecular insights were confirmed through ELISA, qRT‐PCR, western blot analyses. The study was further confirmed by data‐based mathematical modeling using the quantitative data obtained from western blot analysis. 1H NMR based metabolomics study was also performed to unveil metabolite discriminations among various studied groups. Key findings: We identified that the HCC condition was produced due to the IL‐6 induced activation of JAK2 and STAT3 which, in turn, was due to enhanced phosphorylation of JAK2 and STAT3. The treatment with FOIs led to the significant blockade of the IL‐6 mediated JAK2/STAT3 signaling pathway. Besides, FOIs showed their potential ability in restoring perturbed metabolites linked to HCC. In particular, the anticancer efficacy of compound 13a was comparable or somewhat better than marketed chemotherapeutics, 5‐flurouracil. Significance: These findings altogether opened up possibilities of developing fused oxazepino‐indoles (FOIs) as new candidate molecule for plausible alternative of paullones to treat liver cancer.

6,7-dimethoxy-1,2,3,4-tetrahydro-isoquinoline-3-carboxylic acid attenuates colon carcinogenesis via blockade of IL-6 mediated signals

In this study, we investigated the in vivo antiproliferative activity of 6,7-dimethoxy-1,2,3,4-tetrahydro-isoquinoline-3-carboxylic acid (M1) in dimethylhydrazine (DMH) induced colorectal carcinoma (CRC) using albino Wistar rats. M1 was administered to DMH induced CRC rats at 10 and 25 mg/kg doses for 15 days. Various physiological, oxidative parameters, histopathology, ELISA, gene and protein expression studies were conducted to evaluate the anti-CRC potential of M1. The histopathology and biochemical tests indicated the protective action of M1 in DMH-induced colon cancer. ELISA confirms that M1 reduced the increased concentration of IL-6 more prominently than those of IL-2 and COX-2. Gene expression analysis revealed that M1 attenuated the increased mRNA over-expression of IL-6, JAK2 and STAT3. The result obtained from quantitative western blot analysis demonstrated that the CRC condition was produced by the IL-6 induced activation/phosphorylation of JAK2 and STAT3 and further down-regulated with M1 treatment. This evidence was supported well with the application of data-based mathematical modeling. Applying the fitted model, we predicted the quantitative behavior of STAT3 populations not accessible to experimental measurement. Later, 1H NMR based serum metabolic profiling was carried out using rat sera to investigate the impact of M1 on CRC-induced metabolic alterations. M1 showed its ability to restore the perturbed metabolites in CRC condition. Altogether, our study provided the first time evidence that M1 exhibits anti-CRC potential through the blockade of IL-6/JAK2/STAT3 oncogenic signaling.

Novel 1,4-benzothazines obliterate COX-2 mediated JAK-2/STAT-3 signals with potential regulation of oxidative and metabolic stress during colorectal cancer

&NA; 1,4‐benzothiazines have ameliorative effects through inhibition of COX‐2 mediated STAT‐3 pathways at G‐protein couple receptor site. As per this scenario, we recently prepared and tested novel 1,4‐benzothiazine derivatives against HT‐29 human colon cancer cell line. Two compounds namely AR13 and AR15 showed higher inhibitions among all the synthesized compounds. In the present context, we conducted the in vivo antiproliferative action and identified the molecular mechanism associated to cytotoxic action of AR13 and AR15 in dimethylhydrazine (DMH) induced colorectal carcinoma (CRC) model. Various physiological, oxidative stress, histopathology, ELISA, qRT‐PCR, western blot and NMR‐based metabolomics were accomplished to evaluate the anticancer effect of titled compounds. Both compounds were subjected to histological and biochemical tests to observe the protective action of the compounds. ELISA showed potential role of these compounds to normalize increased levels of IL‐2, IL‐6 and COX‐2 mediators. This action was more pronounced for COX‐2 rather than IL‐2 and IL‐6. Gene expression analyses further revealed that both of them attenuated the over‐expressed COX‐2 gene. Furthermore, it was confirmed that these compounds exerted antitumor potential via preventing COX‐2 induced JAK‐2 and STAT‐3 phosphorylation. This action was substansiated by immunohistochemistry using JAK2, p‐JAK2, STAT3 and p‐STAT3 targets in colon tissue. Finally, score plots of PLS‐DA models exhibited significant metabolic discriminations between the treated and CRC groups, and both compounds showed ability to restore the imbalance of multiple metabolites during CRC. In conclusion, our study provided the evidence towards better antiproliferative effect of AR13 and AR15 in DMH‐induced CRC through the blockade of COX‐2/JAK‐2/STAT‐3 signal transduction pathway and could be demonstrated as useful anti‐CRC candidate molecules for future anticancer therapy. Graphical abstract Figure. No caption available.

5H-benzo[h]thiazolo[2,3-b]quinazolines ameliorate NDEA-induced hepatocellular carcinogenesis in rats through IL-6 downregulation along with oxidative and metabolic stress reduction

5H-benzo[h]thiazolo[2,3-b]quinazoline scaffold is known to have an antitumor effect on certain types of malignancies; however, its effect on hepatocellular carcinoma (HCC) remains unclear. Previously, we reported p-toluenesulfonic acid-promoted syntheses, molecular modeling and in vitro antitumor activity of 5H-benzo[h]thiazolo[2,3-b]quinazoline against human hepatoma (Hep-G2) cells where compounds 4A and 6A were found to be potent inhibitors among the series. In continuation to our previous effort to develop novel therapeutic strategies for HCC treatment, here we investigated the in vivo antitumor activity and the mechanism underlying the effects of 4A and 6A in N-nitrosodiethylamine (NDEA)-induced HCC using male Wistar rats. NDEA was administered weekly intraperitoneally at a dose of 100 mg/kg for 6 weeks. Various physiological and morphological changes, oxidative parameters, liver marker enzymes and cytokines were assessed to evaluate the antitumor effect of 4A and 6A. In addition, proton nuclear magnetic resonance-based serum metabolomics were performed to analyze the effects of 4A and 6A against HCC-induced metabolic alterations. Significant tumor incidences with an imbalance in carcinogen metabolizing enzymes and cellular redox status were observed in carcinogenic rats. Tumor inhibitory effects of 4A and 6A were noted by histopathology and biochemical profiles in NDEA-induced hepatic cancer. Compounds 4A and 6A had a potential role in normalizing the elevated levels of inflammatory mediators such as interleukin-1β (IL-1β), IL-2, IL-6 and IL-10. At molecular level, the real-time quantitative reverse-transcribed polymerase chain reaction analysis revealed that 4A and 6A attenuated the IL-6 gene overexpression in hepatic cancer. Further, orthogonal partial least squares discriminant analysis scores plot demonstrated a significant separation of 4A and 6A-treated groups from carcinogen control group. Both the compounds have potential to restore the imbalanced metabolites due to HCC, signifying promising hepatoprotective activities. All these findings suggested that 4A and 6A could be potential drug candidates to treat HCC.