Benzothiazole derivative bearing amide moiety induces p53-mediated apoptosis in HPV16 positive cervical cancer cells.

In our previous study, we screened the anti-cancer properties of 10 benzothiazole derivatives in cervical cancer cell lines. In the present study, we aimed to delineate the mechanism of the apoptotic pathway (whether intrinsic or extrinsic) following the treatment of N-(4-(benzo[d]thiazol-2-yl)phenyl)-5-chloro-2-methoxybenzamide (named as A-07) on cervical cancer cell lines. Cellular stress by reactive oxygen species was measured using DCFDA dye by flowcytometry. Protein expression and localization was checked by immunofluorescence for γH2A.X, TP53, and CASP-3. Expression profiles of BAX and BCL-2 was done by semi-quantitative RT-PCR and PARP-1 (Poly(ADP-ribose) polymerase-1) by Western blot analysis. Bioinformatic studies were done using PDB websites, metaPocket 2.0 server, YASARA software and Discovery Studio 3.5 Visualizer. We demonstrate that the compound A-07 leads to ROS generation and double strand breaks in SiHa and C-33A cells. The induction of apoptosis in SiHa cells is associated with increased nuclear expression of the tumor suppressor protein, TP53. The shift in BAX/BCL-2 ratio, increased expression of Caspase-3 and cleaved Poly(ADP-ribose) polymerase-1 favour apoptotic signal in SiHa. In silico studies revealed that A-07 has inhibiting capabilities to the E6/E6AP/P53 complex. Our data suggest that treatment of A-07 causes p53 and caspase dependent apoptosis in HPV 16 infected SiHa cells.

Green and cost effective synthesis of silver nanoparticles from endangered medicinal plant Withania coagulans and their potential biomedical properties.

Silver nanoparticles (AgNPs) have great potential for their mechanistic role in biomedical researches. Recently, green biosynthetic approaches have been received much attention in plant science for nanoparticles production. Therefore, in the present study AgNPs have been synthesized utilizing in-vitro grown leaf extract of anti-diabetic medicinal plant Withania coagulans Dunal by the reduction of silver nitrate solution. W. coagulans synthesized silver nanoparticles (WcAgNPs) were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, X-ray powder diffraction and Fourier transform Infra-Red spectroscopy. All cumulative results showed that WcAgNPs were ~14 nm in size having spherical shape with face centered cubic structure. High performance liquid chromatography confirmed the involvement of withanolides in AgNPs synthesis as a reducing/capping agent. Synthesized WcAgNPs showed greater antioxidative potential when compared with W. coagulans leaf extract. WcAgNPs have efficient antimicrobial potential and suppresses the growth of both gram positive and gram negative bacteria. In our finding we also observed cytotoxicity of WcAgNPs against SiHa (cervical cancerous, hyper-triploid) cell lines and apoptosis in SiHa cells after 48 hour incubation with 13.74 µg ml-1 (IC50) concentration of WcAgNPs. As results suggested, this is the first report which explain that W. coagulans leaf extract have potential as bio-reducing agent for synthesis of silver nanoparticles, which can be exploited as anti-oxidant, antimicrobial and anti-cancerous agent and depicting an effective way for utilizing bioactive resources in restoration of medicinal properties of this plant with high efficacy.

Protective Effect of Exacum lawii on Cisplatin-induced Oxidative Renal Damage in Rats.

BACKGROUND: Exacum lawii (Gentianaceae), a bitter herb conventionally used in kidney diseases and eye problems, endemic to the Western coast and Southern part of India. AIM: Folklore reports encourage the author to explore the nephroprotective effect of the standardized ethanolic extract of E. lawii against cisplatin-induced renal toxicity in the rat to scientifically validate its traditional use. MATERIALS AND METHODS: Ethanolic extract of the whole plant of E. lawii was standardized with swertiamarin (secoiridoid glycoside) using high-performance liquid chromatography and tested for subacute toxicity according to the OECD guidelines. Nephroprotective potential at different doses of extract was evaluated against cisplatin (6 mg/kg, intraperitoneal) in experimental rats. The changes in serum renal toxicity markers, renal tissue oxidative stress biomarkers, and proinflammatory cytokines level were measured. To estimate the change in oxidative status of renal tissues, DNA and single viable cells were isolated from treated rat kidney, DNA fragmentation assay and flow cytometric analysis of reactive oxygen species (ROS) were performed. Histopathology of renal tissues was also examined. RESULTS: Swertiamerin was found to be 119.59 mg/g of extract. Administration of E. lawii extract (ELE) restored the biochemical parameters. It also decreases the elevated proinflammatory cytokines level in kidney tissues and protected rat kidneys from oxidative stress in rats. Nephroprotective activity was validated by estimating ROS production in kidney live cells and DNA damage in kidney tissue. The histological architecture was also conserved. CONCLUSION: ELE showed significant renal protection against cisplatin through reducing oxidative stress and inflammation. SUMMARY: High-performance liquid chromatography standardisation of Exacum lawii extract with Swertiamerin and its subacute toxicity studyNephroprotective activity of Exacum lawii extract and Swertiamerin was evaluated in cisplatin-induced model and justified by various biochemical parameters and histopathological studyRole of oxidative stress in cisplatin-induced nephrotoxicity was confirmed by measuring levels of antioxidant markers and proinflammatory cytokines in rat renal tissues, ROS estimation by flow cytometry and DNA fragmentation assay by gel electrophoresis in renal cells. Abbreviations used: ELE: Exacum lawii ethanolic extract; WHO: World Health Organization; SOD: Superoxide dismutase; CAT: Catalase; MDA: Malondialdehyde; HPTLC: High performance thin layer chromatography; p.o.: Per oral; i.p.: Intraperitoneal; TNF-α: Tumor necrosis factor alpha; IL-1ß: Interleukin 1 beta; IL-6: Interleukin 6; ROS: Reactive oxygen species.

Benzothiazole derivatives bearing amide moiety: potential cytotoxic and apoptosis-inducing agents against cervical cancer.

Cervical cancer is a major cause of morbidity and mortality in women worldwide. In recent years, benzothiazole analogues have attracted considerable attention in anticancer research. Therefore, in this study, the earlier reported amide series of benzothiazole derivatives were investigated for their antiproliferative activity. The activity of amide derivatives was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometric analysis, apoptosis assay, and DNA fragmentation on two human cervical cancer cell lines: SiHa and C33-A. The data reported from this investigation indicated that benzothiazole derivatives show pronounced cytotoxicity in the HPV16-positive SiHa cells compared with HPV-negative C-33A cells. The in-vitro cytotoxicity of the compounds on the HEK-293 noncancer cell line was evaluated to establish selectivity. Cells treated with benzothiazole derivatives showed prominent morphological features as evidenced by cell shrinkage, membrane blebbing, apoptotic nuclei, and DNA fragmentation. The benzothiazole derivatives show accumulation of cells in the sub-G1 and S-phase of the cell cycle in SiHa and C33-A, respectively. In addition, these derivatives exert their beneficial effect by inducing apoptosis, in the chemoprevention of cervical cancer cells, and were further ascertained using a DNA fragmentation assay. The compounds studied showed potent cytotoxic and apoptotic properties against SiHa and C33-A cancer cell lines and thus represent an excellent starting point for further optimization of therapeutically effective anticancer drugs.

HPV-type-specific response of cervical cancer cells to cisplatin after silencing replication licensing factor MCM4.

Minichoromosome maintenance (MCM) proteins play key role in cell cycle progression by licensing DNA replication only once per cell cycle. These proteins are found to be overexpressed in cervical cancer cells. In this study, we depleted MCM4, one of the MCM 2-7 complex components by RNA interference (RNAi) in four cervical cancer cell lines. The four cell lines were selected on the basis of their human papillomavirus (HPV) infection: HPV16-positive SiHa, HPV18-positive ME-180, HPV16- and HPV18-positive CaSki, and HPV-negative C-33A. The MCM4-deficient cells irrespective of their HPV status grow for several generations and maintain regular cell cycle. We did not find any evidence of augmented response to a short-term (48 h) cisplatin treatment in these MCM4-deficient cells. However, MCM4-/HPV16+ SiHa cells cannot withstand a prolonged treatment (up to 5 days) of even a sublethal dosage of cisplatin. They show increased chromosomal instability compared to their control counterparts. On the other hand, MCM4-deficient CaSki cells (both HPV16+ and 18+) remain resistant to a prolonged exposure to cisplatin. Our study indicates that cervical cancer cells may be using excess MCMs as a backup for replicative stress; however, its regulatory mechanism is dependent on the HPV status of the cells.

PI3K/AKT pathway-mediated regulation of p27(Kip1) is associated with cell cycle arrest and apoptosis in cervical cancer.

BACKGROUND: The cyclin-dependent kinase inhibitor p27(Kip1) is known to act as a putative tumor suppressor in several human cancers, including cervical cancer. Down-regulation of p27(Kip1) may occur either through transcription inhibition or through phosphorylation-dependent proteolytic degradation. As yet, the mechanism underlying p27(Kip1) down-regulation and its putative downstream effects on cervical cancer development are poorly understood. Here we assessed the expression and sub-cellular localization of p27(Kip1) and its effects on proliferation, cell cycle progression and (inhibition of) apoptosis in cervical cancer cells. METHODS: Primary cervical cancer samples (n = 70), normal cervical tissue samples (n = 30) and cervical cancer-derived cell lines (n = 8) were used to assess the expression of p27(Kip1) and AKT1 by RT-PCR, Western blotting and immunohistochemistry, respectively. The effects of the PI3K inhibitor LY294004 and the proteasome inhibitor MG132 on cervical cancer cell proliferation were investigated using a MTT assay. Apoptosis and cell cycle analyses were carried out using flow cytometry, and sub-cellular p27(Kip1) localization analyses were carried out using immunofluorescence assays. RESULTS: We observed p27(Kip1) down-regulation (p = 0.045) and AKT1 up-regulation (p = 0.046) in both the primary cervical cancer samples and the cervical cancer-derived cell lines, compared to the normal cervical tissue samples tested. Treatment of cervical cancer-derived cell lines with the PI3K inhibitor LY294002 resulted in a reduced AKT1 activity. We also observed a dose-dependent inhibition of cell viability after treatment of these cell lines with the proteasome inhibitor MG132. Treatment of the cells with LY294002 resulted in a G1 cell cycle arrest, a nuclear expression of p27(Kip1), and a cytoplasmic p27(Kip1) accumulation after subsequent treatment with MG132. Additionally, we found that the synergistic effect of MG132 and LY294002 resulted in a sub-G1 cell cycle arrest and apoptosis induction through poly (ADP-ribose) polymerase (PARP) cleavage. CONCLUSION: Our data suggest that p27(Kip1) down-regulation in cervical cancer cells is primarily regulated through PI3K/AKT-mediated proteasomal degradation. The observed synergistic effect of the MG132 and LY294002 inhibitors may form a basis for the design of novel cervical cancer therapies.