1. Cancer Biology: Involvement of small molecules in cancer research:

   Small-GTPases use GDP/GTP alternation to actuate a variety of functional switches that are pivotal for cell dynamics. The GTPase switch is turned on by GEFs, which stimulate dissociation of the tightly bound GDP, and turned off by GAPs, which accelerate the intrinsically sluggish hydrolysis of GTP. Rho family proteins regulate diverse cellular functions, including proliferation, differentiation, migration, and polarity. Lots of attention has been given on the involvement of intracellular molecules such as Rho-like proteins in carcinogenesis. Quinacrine (QC), a derivative of 9-aminoacridine, an anti-inflammatory drug that has been used against malaria and rheumatoid diseases. It has been shown to possess anticancer effect both in vitro (cancer cell lines namely, HCT8 and PC3) and in vivo (mouse models). In the cancer cells, QC can simultaneously suppress nuclear factor-B (NF-kappaB) and activate p53 signaling, which results in the induction of apoptosis in these cells. However, the experimental results come from a few limited cancer cell lines, and the detailed mechanisms remain unknown. Existing reports suggest that CDC42- related Rho-family proteins can also activate NF-kappaB pathway but no concrete study has been reported so far about the involvement of quinacrine in regulating Rho-like protein by modulating actin cytoskeleton. Thus, this proposed study will focus for the first time on the effect of quinacrine in changing the balance of Rho-like proteins; which may have implementation on oncogenesis of breast and lung cancer epithelial cancer cells. The study will also focus on the mechanisms underlying the molecular pathways involved in the QC mediated apoptosis in these two cell lines. This study will be helpful for further improvement ofchemotherapeutic reagent for better management of human breast and lung cancer.

2. Toxicology: Effect of Snake venoms on human cancer cells: Envenomation by Russell’s viper is known for its diverse patho-physiological consequences, e.g., myotoxicity, edema, pituitary insufficiency, ‘dramatic hemorrhage’ and renal failure apart from death. The amazing specificity of snake venom toxins to target physiological systems also made them potential molecules of drug development. A number of toxins with anti-cancer potentials have been purified in recent times from different snake venoms, including Russell’s viper venom. The anticancer potential of Russell’s viper venom lies in its cytotoxic effects. Most contemporary research in the development of anticancer therapeutics from venoms has focused on investigating the molecular mechanism by which an agent induces cytotoxicity and apoptosis in cancer cells.
3. Nanotoxicity and effects of nanotoxicity on cell morphology regulation:

   We have done experiments using two different cell lines namely, A549 and IMR32. We have exposed them to different dosages and time to different nanoparticles (NPs). Though we have not propose to use A549 initially but later on we have used this cell line as we thought that inhaled NPs can deposit along the entire respiratory tract, including airways and alveolar regions or penetrate to deeper tissues. Our results confirmed that: ZnO nanoparticle is more toxic to A549 cells as compared to TiO² nanoparticles.  ZnO toxicity is more pronounced by formation of stress granules, appearance of nanotubes, stress fibers and loss of cell-cell contacts whereas, TiO² toxicity is alleviated to some extent with prolonged exposure at 48 hours. RT-PCR and protein profile shows differential regulation pattern for smGTPases upon exposure to various nanoparticles (Cdc42, Rac1 and RhoA) which were not only time dependent but also dependent. Our results indicated not only a dose and time dependent cytotoxicity on exposure to TiO₂ and ZnO NPs but also there is a correlation between cell morphology patterns in both the cell lines. Decrease in metabolic activity was also observed; cytotoxic assay by resarzurin method. SDS PAGE profile shows changes in the pattern of many medium / low range proteins on nanoparticle exposure.  Western blot results revealed differential expression pattern of HSP70 stress protein on nanoparticle exposure.  Ensuing cell death at lethal doses of TiO² and ZnO nanoparticles seem to occur by Necrosis evidenced by absence of DNA laddering. Expression level of total eIF-2 protein as an indicator for protein synthesis inhibition is seen grossly normal though the eIF-2alpha (p) has been showing some changes along with changes in the total protein synthesis pattern by S35 Met labeling experiments. Our work has produced two papers and opened up future work related to ‘NANO-QSAR’ modeling and explores the possible relation between the mechanisms of nanoparticles induced cellular death and protein synthesis.

Awarded external funded projects from Govt. funding agencies like DBT, UGC, ICMR, DAE.