Sujata Patra

Potential Theranostics Application of Bio-Synthesized Silver Nanoparticles (4-in-1 System)

In this report, we have designed a simple and efficient green chemistry approach for the synthesis of colloidal silver nanoparticles (b-AgNPs) that is formed by the reduction of silver nitrate (AgNO3) solution using Olax scandens leaf extract. The colloidal b-AgNPs, characterized by various physico-chemical techniques exhibit multifunctional biological activities (4-in-1 system). Firstly, bio-synthesized silver nanoparticles (b-AgNPs) shows enhanced antibacterial activity compared to chemically synthesize silver nanoparticles (c-AgNPs). Secondly, b-AgNPs show anti-cancer activities to different cancer cells (A549: human lung cancer cell lines, B16: mouse melanoma cell line & MCF7: human breast cancer cells) (anti-cancer). Thirdly, these nanoparticles are biocompatible to rat cardiomyoblast normal cell line (H9C2), human umbilical vein endothelial cells (HUVEC) and Chinese hamster ovary cells (CHO) which indicates the future application of b-AgNPs as drug delivery vehicle. Finally, the bio-synthesized AgNPs show bright red fluorescence inside the cells that could be utilized to detect the localization of drug molecules inside the cancer cells (a diagnostic approach). All results together demonstrate the multifunctional biological activities of bio-synthesized AgNPs (4-in-1 system) that could be applied as (i) anti-bacterial & (ii) anti-cancer agent, (iii) drug delivery vehicle, and (iv) imaging facilitator. To the best of our knowledge, there is not a single report of biosynthesized AgNPs that demonstrates the versatile applications (4-in-1 system) towards various biomedical applications. Additionally, a plausible mechanistic approach has been explored for the synthesis of b-AgNPs and its anti-bacterial as well as anti-cancer activity. We strongly believe that bio-synthesized AgNPs will open a new direction towards various biomedical applications in near future.

Role of Hedgehog Signaling in Ovarian Cancer

Purpose: In humans, several distinctive cancers result from mutations that aberrantly activate hedgehog (HH) signal transduction. Here, we investigate the role of HH signaling in ovarian cancer. Experimental Design: We assessed the expression of different components of hedghehog pathway in primary tumor samples and cell lines. We used specific hedghehog pathway blocker to study the effect on clonal growth and proliferation of ovarian cancer cell both in vitro and in vivo. Results: We show that the up-regulation of several HH pathway components is a common feature of primary ovarian tumors and cell lines. However, expression of PATCHED1 (PTCH1), a direct transcriptional target of the HH pathway, is down-regulated in ovarian cancer in direct contrast to the expression observed in other adult solid tumors. Cyclopamine, a specific HH pathway inhibitor, inhibits the proliferation and clonal growth of ovarian tumor cells in vitro and arrests ovarian tumor growth in vivo. Expression of BMI-1, a polycomb gene, is down-regulated in ovarian cancer cells following cyclopamine treatment. Overexpression of PTCH1 phenocopied the effects of cyclopamine; it down-regulated BMI-1 and reduced clonal growth in ovarian cancer cell lines. Furthermore, knocking down BMI-1 using small interfering RNA also inhibited the clonal growth of all the ovarian cancer cell lines tested. Conclusions: In brief, the constitutive low-level expression of PTCH1 contributes to proliferation and clonal growth of ovarian cancer cells by an aberrant HH signal. Because the HH pathway can be inhibited by specific inhibitors, these findings point toward possible new treatments to inhibit ovarian cancer growth.

In Vivo Toxicity Studies of Europium Hydroxide Nanorods in Mice

Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence and pro-angiogenic properties to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [Eu(III)(OH)(3)] nanorods, synthesized by the microwave technique and characterized by several physico-chemical techniques, can be used as pro-angiogenic agents which introduce future therapeutic treatment strategies for severe ischemic heart/limb disease, and peripheral ischemic disease. The toxicity of these inorganic nanorods to endothelial cells was supported by several in vitro assays. To determine the in vivo toxicity, these nanorods were administered to mice through intraperitoneal injection (IP) everyday over a period of seven days in a dose dependent (1.25 to 125 mg kg(-1) day(-1)) and time dependent manner (8-60 days). Bio-distribution of europium elements in different organs was analyzed by inductively coupled plasma mass spectrometry (ICPMS). Short-term (S-T) and long-term (L-T) toxicity studies (mice euthanized on days 8 and 60 for S-T and L-T, respectively) show normal blood hematology and serum clinical chemistry with the exception of a slight elevation of liver enzymes. Histological examination of nanorod-treated vital organs (liver, kidney, spleen and lungs) showed no or only mild histological changes that indicate mild toxicity at the higher dose of nanorods.

Reactive Oxygen Species Driven Angiogenesis by Inorganic Nanorods

The exact mechanism of angiogenesis by europium hydroxide nanorods was unclear. In this study we have showed that formation of reactive oxygen species (H(2)O(2) and O(2)·-) is involved in redox signaling pathways during angiogenesis, important for cardiovascular and ischemic diseases. Here we used single-walled carbon nanotube sensor array to measure the single-molecule efflux of H(2)O(2) and a HPLC method for the determination of O(2)·- from endothelial cells in response to proangiogenic factors. Additionally, reactive oxygen species-mediated angiogenesis using inorganic nanorods was observed in transgenic (fli1a:EGFP) zebrafish embryos.

Distinct role of PLCβ3 in VEGF-mediated directional migration and vascular sprouting

Endothelial cell proliferation and migration is essential to angiogenesis. Typically, proliferation and chemotaxis of endothelial cells is driven by growth factors such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). VEGF activates phospholipases (PLCs) – specifically PLCγ1 – that are important for tubulogenesis, differentiation and DNA synthesis. However, we show here that VEGF, specifically through VEGFR2, induces phosphorylation of two serine residues on PLCβ3, and this was confirmed in an ex vivo embryoid body model. Knockdown of PLCβ3 in HUVEC cells affects IP3 production, actin reorganization, migration and proliferation; whereas migration is inhibited, proliferation is enhanced. Our data suggest that enhanced proliferation is precipitated by an accelerated cell cycle, and decreased migration by an inability to activate CDC42. Given that PLCβ3 is typically known as an effector of heterotrimeric G-proteins, our data demonstrate a unique crosstalk between the G-protein and receptor tyrosine kinase (RTK) axes and reveal a novel molecular mechanism of VEGF signaling and, thus, angiogenesis.

Inorganic phosphate nanorods are a novel fluorescent label in cell biology

We report the first use of inorganic fluorescent lanthanide (europium and terbium) ortho phosphate [LnPO4·H2O, Ln = Eu and Tb] nanorods as a novel fluorescent label in cell biology. These nanorods, synthesized by the microwave technique, retain their fluorescent properties after internalization into human umbilical vein endothelial cells (HUVEC), 786-O cells, or renal carcinoma cells (RCC). The cellular internalization of these nanorods and their fluorescence properties were characterized by fluorescence spectroscopy (FS), differential interference contrast (DIC) microscopy, confocal microscopy, and transmission electron microscopy (TEM). At concentrations up to 50 μg/ml, the use of [3H]-thymidine incorporation assays, apoptosis assays (TUNEL), and trypan blue exclusion illustrated the non-toxic nature of these nanorods, a major advantage over traditional organic dyes

Sonochemically prepared BSA microspheres containing Gemcitabine, and their potential application in renal cancer therapeutics

This report demonstrates the formation and characterization of sonochemically prepared bovine serum albumin (BSA)-Gemzar (Gemcitabine) microspheres and shows their increased anticancer activity compared to pristine Gemzar. The amount of loaded Gemzar was determined by light absorption measurements. The BSA-Gemzar composite was analyzed and characterized by optical microscopy and scanning electron microscopy. The release kinetics of Gemzar from the proteinaceous microspheres was tested. The BSA-Gemzar composite was examined for its anticancer activity (in vitro) in renal cancer cells (RCC, 786-O cells) using [(3)H]thymidine incorporation assays. It was found that the influence of the Gemzar-loaded microspheres on the cancer cells was significantly greater than that of an equimolar concentration of pristine Gemzar.