The Facile Synthesis of Eco-Friendly Zinc Magnesium Bimetal Nanoparticles and its Application in the Eradication of Xanthomonas oryzae pv. oryzae that Causes Leaf Blight Disease of Rice.

In this research work, we formulated and successfully assessed the antibacterial capability of zinc magnesium bimetal nanoparticles (ZnMgNPs) against Xanthomonas oryzae pv. oryzae (Xoo), the pathogenic microorganism responsible for causing the destructive leaf blight disease in rice. Successful preparation of ZnMgNPs were determined by UV-vis spectroscopy, EDX (Energy dispersive X-ray), FTIR (Fourier transform infrared) and SEM (Scanning Electron Microscopy). ZnMgNPs had antibacterial efficacy towards Xoo at MIC (minimum inhibitory concentration) 50 µg/ml. ZnMgNPs impeded the formation of biofilm of Xoo by drastically reducing the amount of EPS (extracellular polymeric substances) production and number of sessile cells. The ZnMgNPs also reduced several pathogenic traits of Xoo like motility, xanthomonadin and exoenzymes production. ZnMgNPs target cell membrane of Xoo and also induced oxidative damage as mechanisms of its antibacterial activity. As revealed by an ex-vivo study, ZnMgNPs diminished BLB (bacterial leaf blight) disease symptoms in rice leaves, ZnMgNPs had no effect on rice seed germination, and that following foliar application, the length and biomass of roots and shoots of rice seedling were unaffected, low cytotoxic to A549 cell line showing that ZnMgNPs are non-toxic. However, with ZnMgNPs treatment, the chlorophyll content index (CCI) increased significantly, indicating a good impact on rice physiology. All of these findings suggest that ZnMgNPs could be applied in agriculture to combat the Xoo-caused BLB disease.

Heavy water (D2O) induces autophagy-dependent apoptotic cell death in non-small cell lung cancer A549 cells by generating reactive oxygen species (ROS) upon microtubule disruption.

OBJECTIVE: Deuterium oxide (D2O) or heavy water is known to have diverse biological activities and have a few therapeutic applications due to its limited toxicity to human subjects. In the present study, we investigated the mechanism of D2O-induced cytotoxicity in non-small cell lung cancer A549 cells. RESULTS: We found that D2O-treatment resulted in cytotoxicity, cell cycle arrest, and apoptosis in A549 cells in a dose-dependent fashion. In contrast, limited cytotoxicity was observed in lung fibroblasts WI38 cells. Moreover, D2O-treatment resulted in the disruption of the cellular microtubule network, accompanied by the generation of ROS. On further investigation, we observed that the intracellular ROS triggered autophagic responses in D2O-treated cells, leading to apoptosis by inhibiting the oncogenic PI3K/ Akt/ mTOR signaling. D2O-treatment was also found to enhance the efficacy of paclitaxel in A549 cells. SIGNIFICANCE: D2O induces autophagy-dependent apoptosis in A549 cells via ROS generation upon microtubule depolymerization and inhibition of PI3K/ Akt/ mTOR signaling. It augments the efficacy of other microtubule-targeting anticancer drug taxol, which indicates the potential therapeutic importance of D2O as an anticancer agent either alone or in combination with other chemotherapeutic drugs.

A novel probiotic strain of Lactobacillus fermentum TIU19 isolated from Haria beer showing both in vitro antibacterial and antibiofilm properties upon two multi resistant uro-pathogen strains.

Probiotics with antimicrobial activity are gaining interest as a topic in the research field. Urinary tract infections (UTIs), acquired in the hospital or the community, are among the most prevalent infections. The emergence of multidrug resistance (MDR) uro-pathogens has made the current situation more critical in terms of global public health. To face this situation, in this study, Lactobacillus fermentum TIU19 (L. fermentum TIU19) was isolated and characterized as a new probiotic strain of the rice-based fermented beverage Haria. Subsequently, we also investigated its application as a biological agent that inhibits the growth of multidrug-resistant uro-pathogens, Escherichia coli, and Enterococcus faecalis. The results showed that, the isolated strain L. fermentum TIU19 was sensitive to all antibiotics tested except vancomycin and was devoid of virulence factors, such as haemolytic and gelatinase activities. Therefore, it may be considered safe for public health. It has many probiotic properties, such as survival in simulated gastrointestinal fluid, antioxidant activity, ß-galactosidase producing ability, high cell surface hydrophobicity, adhesion ability to epithelial cells, and strong biofilm producer. The growth inhibitory and antibiofilm activities were shown against two uro-pathogens. All these results suggest that L. fermentum TIU19 can be explored as a potential probiotic with antagonistic activity against MDR uro-pathogenic E. coli and E. faecalis.

Photodynamic antibacterial and antibiofilm activity of riboflavin against Xanthomonas oryzae pv oryzae: an ecofriendly strategy to combat bacterial leaf blight (BLB) rice disease.

Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv oryzae (Xoo), is one of the most damaging rice diseases, causing severe production losses depending on the rice variety. The purpose of this study was to develop an antibacterial photodynamic treatment (aPDT) using riboflavin for the treatment of BLB disease. Combining light and riboflavin (RF) therapy significantly reduced bacterial planktonic cells compared to RF alone. Photoactivated riboflavin also decreased biofilm biomass by reducing the number of viable sessile cells and the production of extracellular polymeric substances (EPS). Reactive oxygen species (ROS) levels in Xoo cells treated with photoactivated riboflavin were found to be significantly higher than in cells treated with riboflavin and light individually. Malondialdehyde (MDA) increased greatly in photoactivated riboflavin treated cells, indicating that severe oxidative damage was induced. Subsequently, a reduction in lactate dehydrogenase (LDH) activity in photoactivated riboflavin treated Xoo cells indicates that oxidative stress has disrupted the respiratory system, leading to bacterial cell death. In an ex vivo aPDT assay, photoactivated riboflavin successfully eradicated Xoo on the surface of rice leaves. Photoactivated riboflavin had no side effects on rice seed germination in subsequent trials, indicating that it is safe for agricultural applications. Therefore, all these findings suggest that aPDT is a potential alternative management strategy for BLB disease.

Tetracycline-loaded magnesium oxide nanoparticles with a potential bactericidal action against multidrug-resistant bacteria: In vitro and in vivo evidence.

Worldwide, the emergence of diarrhoea-causing multi-drug resistant (MDR) bacteria has become a crucial problem in everyday life. Tetracycline (TC) is a bacteriostatic agent that has a wide spectrum of antibacterial activity. One potential strategy to enhance the penetration and antibacterial activity of antibiotics is the use of nanotechnology. In this context, this study dealt with the synthesis of TC loading in biocompatible magnesium oxide nanoparticles (MgONPs), its characterization, and the potency of killing against diarrhoea-causing MDR bacteria E. coli and S. flexneri. TC loaded- MgONPs (MgONPs-TC) were characterized by DLS, SEM-EDS, UV-vis spectroscopy, and FTIR techniques with adequate physical properties. Antibacterial and antibiofilm studies indicate that this nanoparticle successfully eradicated both planktonic and sessile forms of those bacteria. It also significantly reduced the production of bacterial EPS, different levels of antioxidant enzymes, and induced reactive oxygen species (ROS) in the bacterial cell as a mode of antibacterial action. In particular, MgONPs-TC were efficient in reducing the colonization of MDR E. coli and S. flexneri in the C. elegans model. Therefore, all these data suggest that MgONPs-TC are a highly promising approach to combating diseases associated with diarrhoea-causing MDR bacteria in the medical field with limited health care budgets.

Oxidative stress, DNA, and membranes targets as modes of antibacterial and antibiofilm activity of facile synthesized biocompatible keratin-copper nanoparticles against multidrug resistant uro-pathogens.

Escherichia coli and Enterococcus faecalis are two of the most prevalent uro-pathogens and are difficult to treat as they acquire multidrug-resistant traits. In this study, the main objective was to develop biocompatible copper nanoparticles using chicken feather keratin protein (CuNPs-K) and to investigate their impact on multidrug-resistant (MDR) uro-pathogens, E. coli and E. faecalis, under both single and mixed culture conditions. CuNPs-K were characterised by UV-Vis spectroscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, and docking experiments. The MIC values of CuNPs-K against single and mixed planktonic cultures were 50 µg/ml and 75 µg/ml, respectively. CuNPs-K efficiently disrupted the biofilm of single and mixed uro-pathogen cultures by eliminating sessile cells. This biofilm disruption may be attributed to a decline in the production of extracellular polymeric substances in both single and mixed bacterial cultures treated with CuNPs-K. Moreover, selective antimicrobial activity was determined by selectivity assays using T24 cells. CuNPs-K targets both the bacterial membrane and DNA with elevated reactive oxygen species (ROS) as their bactericidal mode of action. This comprehensive antimicrobial activity of CuNPs-K was further confirmed in vivo by using the zebra fish model. In this study, CuNPs-K effectively reduced bacterial load with increased survivability of infected zebrafish. All these results suggest that CuNPs-K can be explored as an exceptional antibacterial agent against MDR uro-pathogenic E. coli and E. faecalis.

Exploring the antibacterial, antibiofilm, and antivirulence activities of tea tree oil-containing nanoemulsion against carbapenem-resistant Serratia marcescens associated infections.

Carbapenem-resistant Serratia marcescens (CRE-S. marcescens) has recently emerged as an opportunistic human pathogen that causes various nosocomial and respiratory tract infections. The prognosis for CRE-S. marcescens-related infections is very poor and these infections are difficult to treat. This study investigated the synthesis of tea tree oil nanoemulsion (TTO-NE) and its impact on CRE-S. marcescens both in vitro and in vivo. TTO-NE was characterized by dynamic light scattering (DLS) and effectively eradicated bacterial planktonic and sessile forms, reduced bacterial virulence factors, and generated reactive oxygen species (ROS) in the bacterial cell. Notably, TTO-NE was efficient in reducing the colonization of CRE-S. marcescens in a C. elegans in vivo model. The data suggest that TTO-NE might be an excellent tool to combat infections associated with CRE-S. marcescens.

Antibacterial, anti-biofilm, and anti-virulence potential of tea tree oil against leaf blight pathogen Xanthomonas oryzae pv. oryzae instigates disease suppression.

Bacterial leaf blight (BLB) disease, caused by Xanthomonas oryzae pv. oryzae (Xoo), causes major annual economic losses around the world. Inorganic copper compounds and antibiotics are conventionally used to control BLB disease. They often cause environmental pollution, contributing to adverse effects on human health. Therefore, research is now leading to the search for alternative control methods. Tea tree oil (TTO) is obtained from a traditional medicinal plant, Melaleuca alternifolia, with antibacterial properties. In this study, we found that TTO showed antibacterial activity against Xoo with a minimum inhibitory concentration (MIC) of 18 mg/ml. These antagonistic activities were not limited only to planktonic cells, as further studies have shown that TTO effectively eradicated sessile cells of Xoo in both initial and mature biofilms. Furthermore, it was also observed that TTO reduced various key virulence properties of Xoo, such as swimming, swarming motility, and the production of extracellular polymeric substances, xanthomonadin, and exoenzymes. TTO triggered ROS generation with cell membrane damage as an antibacterial mode of action against Xoo. The in silico study revealed that 1,8-cineole of TTO was effectively bound to two essential proteins, phosphoglucomutase and peptide deformylase, responsible for the synthesis of EPS and bacterial survival, respectively. These antibacterial and anti-virulence activities of TTO against Xoo were further confirmed by an ex vivo virulence assay where TTO significantly reduced the lesion length caused by Xoo on rice leaves. All these data concluded that TTO could be a safe, environment-friendly alternative approach for the comprehensive management of BLB disease.

Allelochemical catechol comprehensively impedes bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae (Xoo) induces bacterial leaf blight (BLB), is known to be the most devastating disease of rice. The present investigation for the first time explains the antibacterial, anti-biofilm, and antivirulence potential of the simplest allelochemical catechol. Bacterial viability and growth are significantly reducing in catechol treatment. Further study also reveals that catechol also inhibits primary attachment and preformed biofilm of Xoo even at half MIC concentration. The half MIC concentration of catechol also induce a significant decrease in virulence factors like swimming, swarming, exopolysaccharide, and xanthomonadin production. Next, we investigate the possible antibacterial mode of action of catechol against Xoo. Results show that, the catechol caused oxidative stress and targets cell membrane for its antibacterial activity. Whereas, in silico study reveals that, catechol binds with the catalytic domain of XanA protein and this may be consider as a reason for antibiofilm activity of catechol. Moreover, in virulence assay on rice plants, we observe significant decrement in lesion length in catechol and Xoo co-treated rice leaves as compared with only Xoo treated leaves. All the results clearly show, allelochemical catechol to be a potential compound for the antibacterial, anti-biofilm, and antivirulence agent against Xoo and consequently mitigating the BLB disease advancement in rice.

Photodynamic antimicrobial chemotherapy (PACT) using riboflavin inhibits the mono and dual species biofilm produced by antibiotic resistant Staphylococcus aureus and Escherichia coli.

PURPOSE: Multispecies biofilms play a significant role in persistent infections. Furthermore, by interspecies transfer of antibiotic resistance genes, multispecies biofilms spread antibiotic resistance. The purpose of this study was to investigate the effect of Photodynamic Antimicrobial Chemotherapy (PACT) using riboflavin on mono and multi species biofilms. METHODS: For this we used two clinically relevant opportunistic pathogens species E. coli and S. aureus as mono-species and multispecies biofilms. We did broth dilution assay for antibacterial, crystal violet assay for biofilms and fluorometric study for reactive oxygen species (ROS) and extracellular polymeric substance (EPS) production by phenol-HCl method. RESULTS: Antibacterial study revealed that photo-illuminated riboflavin shows bactericidal effect against each bacteria and their mix culture. E. coli was found to be little more resistant than S. aureus. Crystal violet assay revealed photo-illuminated riboflavin shows anti-biofilms activity against both mono and mix species biofilms. But mix species biofilms were more resistant to PACT than mono species biofilms. Further study revealed this may be due to the interaction between different EPS production, hence in mix species biofilms EPS production is less affected after PACT than mono species biofilms. We found photo-illuminated riboflavin increased the intracellular ROS production. CONCLUSION: Photo-illuminated riboflavin shows bactericidal and anti-biofilms effect against each bacteria and their mix culture. Photo-illuminated increased intracellular ROS production, which may induce the oxidative stress and destroy the respiratory system of bacteria.

Sodium alginate-based edible coating containing nanoemulsion of Citrus sinensis essential oil eradicates planktonic and sessile cells of food-borne pathogens and increased quality attributes of tomatoes.

There is a growing interest from the worldwide scientific community in formulating edible- biodegradable coatings to replace non-biodegradable and expensive commercial wax-based coatings for preserving postharvest quality attributes of vegetables including tomatoes. Postharvest tomatoes are a suspected vehicle for both Salmonella and Listeria in food poisoning incidents. In this work, the effectiveness of edible nano-emulsion coatings containing sweet orange essential oil and sodium alginate were prepared and characterized, then evaluated antibacterial and antibiofilm activity against Salmonella and Listeria and simultaneously, examined its coating effect on various quality characteristics of tomatoes at 22 ± 2 °C over a 15 days storage period. DLS (Dynamic light scattering) study revealed stable nanoemulsion formulation with 43.23 nm particle size. The high whiteness index of nanoemulsion has a positive impact on product marketability and desirability. Antibacterial and antibiofilm studies revealed nanoemulsion effectively eradicate both sessile and planktonic forms of Salmonella and Listeria in both single and multi-species culture conditions. Tomatoes coated with edible coating significantly enhanced firmness up to 33%, decreased total mesophilic bacteria including Salmonella and Listeria, and reduced weight loss up to 3 fold lower than uncoated one. Sensory analysis revealed that the use of the edible coating increased the total acceptance scores of tomatoes.

Antibacterial, anti-biofilm activity and mechanism of action of pancreatin doped zinc oxide nanoparticles against methicillin resistant Staphylococcus aureus.

Staphylococcus aureus are known to cause diseases from normal skin wound to life intimidating infections. Among the drug resistant strain, management of methicillin resistant Staphylococcus aureus (MRSA) is very difficult by using conventional antibiotic treatment. Both Zinc oxide nanoparticles (ZnONPs) and pancreatin (PK) are known to have antibacterial activity. Our main objective is to dope PK on ZnONPs to reduced zinc-oxide toxicity but increased anti-bacterial and anti-biofilms activity. In present study, we showed that, functions of zinc oxide nanoparticles with pancreatin enzyme (ZnONPs-PK) have anti-bacterial, anti-biofilms, anti-motility and anti-virulence properties against MRSA. Moreover, ZnONPs-PK were more potent to eradicate MRSA than only ZnONPs and PK. Application of the produced nano-composites as treatment on infected swine dermis predominantly reflects the potential treatment property of it. The vancomycin sensitivity of MRSA was significantly increased on application with ZnONPs-PK. Further study revealed cell membrane was the target of the ZnONPs-PK and that leads to oxidative damage of the cells. The produced nanoparticles were found completely non-toxic to human's keratinocytes and lung epithelial cell lines at its bactericidal concentration. Overall, this study emphasizes the potential mechanisms underlying the selective bactericidal properties of ZnONPs-PK against MRSA. This novel nanoparticle strategy may provide the ideal solution for comprehensive management of MRSA and its associated diseases with minimising the use of antibiotics.

A novel triazole, NMK-T-057, induces autophagic cell death in breast cancer cells by inhibiting γ-secretase-mediated activation of Notch signaling.

Notch signaling is reported to be deregulated in several malignancies, including breast, and the enzyme γ-secretase plays an important role in the activation and nuclear translocation of Notch intracellular domain (NICD). Hence, pharmacological inhibition of γ-secretase might lead to the subsequent inhibition of Notch signaling in cancer cells. In search of novel γ-secretase inhibitors (GSIs), we screened a series of triazole-based compounds for their potential to bind γ-secretase and observed that 3-(3'4',5'-trimethoxyphenyl)-5-(N-methyl-3'-indolyl)-1,2,4-triazole compound (also known as NMK-T-057) can bind to γ-secretase complex. Very interestingly, NMK-T-057 was found to inhibit proliferation, colony-forming ability, and motility in various breast cancer (BC) cells such as MDA-MB-231, MDA-MB-468, 4T1 (triple-negative cells), and MCF-7 (estrogen receptor (ER)/progesterone receptor (PR)-positive cell line) with negligible cytotoxicity against noncancerous cells (MCF-10A and peripheral blood mononuclear cells). Furthermore, significant induction of apoptosis and inhibition of epithelial-to-mesenchymal transition (EMT) and stemness were also observed in NMK-T-057-treated BC cells. The in silico study revealing the affinity of NMK-T-057 toward γ-secretase was further validated by a fluorescence-based γ-secretase activity assay, which confirmed inhibition of γ-secretase activity in NMK-T-057-treated BC cells. Interestingly, it was observed that NMK-T-057 induced significant autophagic responses in BC cells, which led to apoptosis. Moreover, NMK-T-057 was found to inhibit tumor progression in a 4T1-BALB/c mouse model. Hence, it may be concluded that NMK-T-057 could be a potential drug candidate against BC that can trigger autophagy-mediated cell death by inhibiting γ-secretase-mediated activation of Notch signaling.

Novel nano-insulin formulation modulates cytokine secretion and remodeling to accelerate diabetic wound healing.

Little is known about insulin's wound healing capability in normal as well as diabetic conditions. We here report specific interaction of silver nanoparticles (AgNPs) with insulin by making a ~2 nm thick coat around the AgNPs and its potent wound healing efficacy. Characterization of the interaction of human insulin with silver nanoparticles showed confirmed alteration of amide-I in insulin whereas amide-II and III remained unaltered. Further, nanoparticles protein interaction kinetics showed spontaneous interaction at physiological temperature with ΔG, ΔS, Ea and Ka values -7.48, 0.076, 3.84 kcal mol-1 and 6 × 105 s-1 respectively. Insulin loaded AgNPs (IAgNPs) showed significant improvement in healing activity in vitro (HEKa cells) and in vivo (Wister Rats) in comparison with the control in both normal and diabetic conditions. The underlying mechanism was attributed to a regulation of the balance between pro (IL-6, TNFα) and anti-inflammatory cytokines (IL-10) at the wound site to promote faster wound remodeling.

Theaflavin and epigallocatechin-3-gallate synergistically induce apoptosis through inhibition of PI3K/Akt signaling upon depolymerizing microtubules in HeLa cells.

Theaflavin (TF) and epigallocatechin-3-gallate (EGCG) both have been reported previously as microtubule depolymerizing agents that also have anticancer effects on various cancer cell lines and in animal models. Here, we have applied TF and EGCG in combination on HeLa cells to investigate if they can potentiate each other to improve their anticancer effect in lower doses and the underlying mechanism. We found that TF and EGCG acted synergistically, in lower doses, to inhibit the growth of HeLa cells. We found the combination of 50 µg/mL TF and 20 µg/mL EGCG to be the most effective combination with a combination index of 0.28. The same combination caused larger accumulation of cells in the G 2 /M phase of the cell cycle, potent mitochondrial membrane potential loss, and synergistic augmentation of apoptosis. We have shown that synergistic activity might be due to stronger microtubule depolymerization by simultaneous binding of TF and EGCG at different sites on tubulin: TF binds at vinblastine binding site on tubulin, and EGCG binds near colchicines binding site on tubulin. A detailed mechanistic analysis revealed that stronger microtubule depolymerization caused effective downregulation of PI3K/Akt signaling and potently induced mitochondrial apoptotic signals, which ultimately resulted in the apoptotic death of HeLa cells in a synergistic manner.

Azadiradione ameliorates polyglutamine expansion disease in Drosophila by potentiating DNA binding activity of heat shock factor 1.

Aggregation of proteins with the expansion of polyglutamine tracts in the brain underlies progressive genetic neurodegenerative diseases (NDs) like Huntington's disease and spinocerebellar ataxias (SCA). An insensitive cellular proteotoxic stress response to non-native protein oligomers is common in such conditions. Indeed, upregulation of heat shock factor 1 (HSF1) function and its target protein chaperone expression has shown promising results in animal models of NDs. Using an HSF1 sensitive cell based reporter screening, we have isolated azadiradione (AZD) from the methanolic extract of seeds of Azadirachta indica, a plant known for its multifarious medicinal properties. We show that AZD ameliorates toxicity due to protein aggregation in cell and fly models of polyglutamine expansion diseases to a great extent. All these effects are correlated with activation of HSF1 function and expression of its target protein chaperone genes. Notably, HSF1 activation by AZD is independent of cellular HSP90 or proteasome function. Furthermore, we show that AZD directly interacts with purified human HSF1 with high specificity, and facilitates binding of HSF1 to its recognition sequence with higher affinity. These unique findings qualify AZD as an ideal lead molecule for consideration for drug development against NDs that affect millions worldwide.

Synthesis of novel 5-arylidenethiazolidinones with apoptotic properties via a three component reaction using piperidine as a bifunctional reagent.

The synthesis of a new library of 5-arylidenethiazolidinone compounds using an efficient three component reaction with thiazolidine-2,4-dione, piperidine and appropriate aldehydes is reported. This reaction is excellently high yielding, tolerant towards a variety of aldehydes and provides access to these compounds in a single step (in comparison to low yielding multistep syntheses reported in the literature). Once the reaction is complete, the desired product precipitates out of the reaction mixture and is isolated by filtration and purified by washing and recrystallization. These compounds revealed anti-proliferative activities against human breast cancer cells (MCF7 and MDA). Phenotypic profiling established the most active compound 17i (EC50 = 4.52 µM) as an apoptotic agent. A novel chemical proteomics approach identified ß-actin-like protein 2, γ-enolase and macrophage migration inhibitory factor (MMIF) as putative cellular binding partners of 17i.

Development of Novel Bis(indolyl)-hydrazide-Hydrazone Derivatives as Potent Microtubule-Targeting Cytotoxic Agents against A549 Lung Cancer Cells.

The biological significance of microtubules makes them a validated target of cancer therapy. In this study, we have utilized indole, an important pharmacological scaffold, to synthesize novel bis(indolyl)-hydrazide-hydrazone derivatives (NMK-BH compounds) and recognized NMK-BH3 as the most effective one in inhibiting A549 cell proliferation and assembly of tissue-purified tubulin. Cell viability experiments showed that NMK-BH3 inhibited proliferation of human lung adenocarcinoma (A549) cells, normal human lung fibroblasts (WI38) and peripheral blood mononuclear cells (PBMC) with IC50 values of ∼2, 48.5, and 62 µM, respectively. Thus, the relatively high cytotoxicity of NMK-BH3 toward lung carcinoma (A549) cells over normal lung fibroblasts (WI38) and PBMC confers a therapeutic advantage of reduced host toxicity. Flow cytometry, Western blot, and immunofluorescence studies in the A549 cell line revealed that NMK-BH3 induced G2/M arrest, mitochondrial depolarization, and apoptosis by depolymerizing the cellular interphase and spindle microtubules. Consistent with these observations, study in cell free system revealed that NMK-BH3 inhibited the microtubule assembly with an IC50 value of ∼7.5 µM. The tubulin-ligand interaction study using fluorescence spectroscopy indicated that NMK-BH3 exhibited strong and specific tubulin binding with a dissociation constant of ∼1.4 µM at a single site, very close to colchicine site, on ß-tubulin. Collectively, these findings explore the cytotoxic potential of NMK-BH3 by targeting the microtubules and inspire its development as a potential candidate for lung cancer chemotherapy.

Colchicine induces autophagy and senescence in lung cancer cells at clinically admissible concentration: potential use of colchicine in combination with autophagy inhibitor in cancer therapy.

Colchicine is a well-known and potent microtubule targeting agent, but the therapeutic value of colchicine against cancer is limited by its toxicity against normal cells. But, there is no report of its cytotoxic potential against lung cancer cell, at clinically permissible or lower concentrations, minimally toxic to non-cancerous cells. Hence, in the present study, we investigated the possible mechanism by which the efficacy of colchicine against lung cancer cells at less toxic dose could be enhanced. Colchicine at clinically admissible concentration of 2.5 nM had no cytotoxic effect and caused no G2/M arrest in A549 cells. However, at this concentration, colchicine strongly hindered the reformation of cold depolymerised interphase and spindle microtubule. Colchicine induced senescence and reactive oxygen species mediated autophagy in A549 cells at this concentration. Autophagy inhibitor 3-methyladenine (3-MA) sensitised the cytotoxicity of colchicine in A549 cells by switching senescence to apoptotic death, and this combination had reduced cytotoxicity to normal lung fibroblast cells (WI38). Together, these findings indicated the possible use of colchicine at clinically relevant dose along with autophagy inhibitor in cancer therapy.

Potential role of autophagy in smokeless tobacco extract-induced cytotoxicity and in morin-induced protection in oral epithelial cells.

Toxic components of STE induced serious, adverse human oral health outcomes. In the present study, we observed that STE was involved in oral toxicity by reducing the viability of human squamous epithelial cells, SCC-25, along with the simultaneous induction of both apoptosis and autophagic signaling. STE was also found to induce significant amount ROS generation in SCC-25 cells. The dietary flavonoid morin, found abundantly in a variety of herbs, fruits and wine, has been reported to attenuate ROS-induced pathogenesis including autophagy. In this study we designed three different treatment regimes of morin treatment, such as pre, co, and post - treatment of STE challenged SCC-25 cells. In all cases morin provided cytoprotection to STE challenged SCC-25 cells by augmenting STE induced ROS-dependent cytotoxic autophagy. Hence, morin is a potential option for antioxidant therapy in treatment of STE induced toxicity.