N-(2-hydroxyphenyl)-2-phenazinamine from Nocardiopsis exhalans induces p53-mediated intrinsic apoptosis signaling in lung cancer cell lines.

The present study aims to investigate the effect and the molecular mechanism of N-(2-hydroxyphenyl)-2-phenazinamine (NHP) isolated from Nocardiopsis exhalans against the proliferation of human lung cancer cells. The cytotoxic activity of NHP against A549 and H520 cells was determined using MTT assay. The cytotoxic activity of NHP against A549 and H520 lung cancer cells showed excellent activity at 75 µg/mL and damage the mitochondrial membrane and nucleus by generating oxidative stress. NHP causes nuclear condensation and induces apoptosis which was confirmed using AO/EB and PI/DAPI dual staining assay. Moreover, the NHP downregulates the oncogenic genes such as IL-8, TNFα, MMPs and BcL2 and also upregulates the expression of apoptosis marker genes such as Cyto C, p53, p21, caspase 9/3 in A549 and H520 human lung cancer cells. Considering the strong anticancer activity of NHP against lung cancer, NHP may be further evaluated as a potential anticancer drug for the treatment of lung cancer.

Target delivery of doxorubicin tethered with PVP stabilized gold nanoparticles for effective treatment of lung cancer.

Development of drug delivery system conjugated with doxorubicin (dox) on the surface of AuNPs with polyvinylpyrrolidone (Dox@PVP-AuNPs), we have demonstrated that human lung cancer cells can significantly overcome by the combination of highly effective cellular entry and responsive intracellular release of doxorubicin from Dox@PVP-AuNPs complex. Previously drug release from doxorubicin-conjugated AuNPs was confirmed by the recovered fluorescence of doxorubicin from quenching due to the nanosurface energy transfer between doxorubicinyl groups and AuNPs. Dox@PVP-AuNPs achieved enhanced inhibition of lung cancer cells growth than free Doxorubicin and PVP-AuNPs. The in vitro cytotoxic effect of PVP-AuNPs, free Dox and Dox@PVP-AuNPs inhibited the proliferation of human lung cancer cells with IC50 concentration. Compared with control cells, PVP-AuNPs and free Dox, Dox@PVP-AuNPs can increases ROS generation, sensitize mitochondrial membrane potential and induces both early and late apoptosis in lung cancer cells. Moreover, Dox@PVP-AuNPs highly upregulates the expression of tumor suppressor genes than free Dox and PVP-AuNPs and induces intrinsic apoptosis in lung cancer cells. From the results, Dox@PVP-AuNPs can be considered as an potential drug delivery system for effective treatment of human lung cancer.

p53 mediated transcriptional regulation of long non-coding RNA by 1-hydroxy-1-norresistomycin triggers intrinsic apoptosis in adenocarcinoma lung cancer.

Over a few decades, systemic chemotherapy and surgery are the only treatment options for lung cancer. Due to limited efficacy and overall poor survival of patients, it is necessary to develop a newer therapeutic strategy which specifically targets cancer cell proliferation pathway. Deciphering the role of long non-coding RNAs (lncRNAs) in tumorigenesis and pathogenesis of cancer cells has recently emerged. In the present study, marine actinomycetes derived 1-hydroxy-1-norresistomycin (HNM) was used to enhance the expression of lncRNAs through p53 transcriptional regulation and induced intrinsic apoptosis in non-small cell lung cancer cells. Initially, concentration dependent treatment with HNM has increased the ROS generation in mitochondria and sensitizes the mitochondrial membrane potential. Further, HNM downregulates the numerous oncogenes which regulate cancer cell proliferation, metastasis and invasion and tumor suppressor genes which are involved in intrinsic apoptosis confirmed with adopting techniques such as RT-PCR and western blot analysis. Moreover, ChIP assay results showed that HNM upregulates the p53 mediated transcriptional regulation of lncRNAs lead to apoptosis of cancer cells through cell cycle arrest and inhibition of proliferation. In conclusion, HNM found to be a potential therapeutic agent for treatment of lung cancer via suppression of oncogenes and expression of wide range of tumor suppressor genes are might have significant implications in cancer treatment and drug development.

Anticancer activity of graphene oxide-reduced graphene oxide-silver nanoparticle composites.

In the present study, a chemical route was employed to synthesize graphene oxide (GO)-reduced graphene oxide (rGO)-Ag nanoparticle (AgNP) composites from graphite and AgNO3 using vitamin C as reducing agent. Powder X-ray diffraction pattern and field emission scanning electron microscope images revealed that the AgNP were uniformly distributed on the surface of GO and rGO nanosheets. For the first time, the cytotoxicity of GO, rGO, AgNP, GO-AgNP and rGO-AgNP composites were examined against human lung cancer A549 cells using MTT assay and reported quantitatively. The rGO-AgNP showed significant cytotoxicity activity with an IC50 value of 30µg/mL towards A549 cells which is higher than that of GO (180µg/mL), rGO (160µg/mL) and GO-AgNP (100µg/mL). Compared to AgNP (6µg/mL), rGO-AgNP shows partial agglomeration of AgNP on rGO sheets, which reduces the interaction between rGO-AgNP and A549 cells leading to lesser anticancer activity than AgNP. The interaction between rGO and AgNP leads to increase in the material biocompatibility, reducing the toxicity and corrosive characteristic.

Chemopreventive potential of fungal taxol against 7, 12-dimethylbenz[a]anthracene induced mammary gland carcinogenesis in Sprague Dawley rats.

Breast cancer is the second most prevalent cancer and foremost global public health problem. The present study was designed to appraise the chemopreventive potential of fungal taxol against 7,12-dimethylbenz[a]anthracene (DMBA) induced mammary gland carcinogenesis in Sprague Dawley rats. After 90 days of tumor induction, fungal and authentic taxol were given intraperitoneally once in a week for four weeks. Infrared thermal imaging analysis, serum biochemical parameters such as lipid peroxidase (LPO), creatinine, enzymic and non enzymic antioxidants, liver markers tests such as alanine transaminase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TG) and lipoproteins was analysed. In addition, histopathological observation (breast, kidney and liver), immunohistochemical analysis (p53 and Her2/neu) and western blotting experiments (bcl-2, bax and caspase-9) were performed both in control and experimental animals. In thermal imaging, decreased temperature was observed in rat treated with fungal and authentic taxol when compared to tumor induced rats. The significant decrease in LPO, creatinine, ALT, AST, TC, TG, lipoproteins and increase in enzymic, non-enzymic antioxidants were exemplified in serum of treated groups. Further histopathology, immunohistochemical and western blot analysis (bax, cas-9 and bcl-2) of apoptotic markers in breast tissues clearly showed the anti-carcinogenic property of fungal taxol. Our findings implement that fungal taxol is a potential chemo preventive agent against DMBA induced mammary gland carcinogenesis.

Blocking NF-κB sensitizes non-small cell lung cancer cells to histone deacetylase inhibitor induced extrinsic apoptosis through generation of reactive oxygen species.

NF-κB signalling is one of the main cell survival pathways that attenuate the anticancer efficacy of therapeutic drugs. Previous studies demonstrated that the histone deacetylase (HDAC) inhibitor induces apoptosis in some malignancies through multiple mechanisms including up-regulation of death receptors, disruption of Hsp90 function and generation of reactive oxygen species (ROS). However, HDAC inhibitor also induces a cell survival signal through NF-κB activation. In this report, we found that romidepsin, a class I HDAC inhibitor, induces NF-κB activation in A549 non-small-cell lung cancer (NSCLC) cells. We also found that inhibition of A549 cells with bortezomib (proteasome inhibitor) has blocked IκB degradation that leads to the loss of NF-κB activation and translocation which enhanced the romidepsin induced mitochondrial injury and sensitizes NSCLC cells to apoptosis. Romidepsin significantly enhances NF-κB reporter gene transcription and these effects were inhibited by bortezomib as determined by reporter gene assay. Consistently, the combined exposure of romidepsin and bortezomib reversed the effects on IκB degradation as evident with IL-8, p50 and p65 (NF-κB) expression. Apoptosis was markedly sensitized with greater ROS generation and more cell death in A549 cell lines. These events are most closely related in that bortezomib prevents the romidepsin mediated RelA acetylation and NF-κB activation, resulting in caspase activation. A strategy of blocking NF-κB activation to enhance HDAC inhibitor activity warrants further attention in NSCLC cells.

Romidepsin induces cell cycle arrest, apoptosis, histone hyperacetylation and reduces matrix metalloproteinases 2 and 9 expression in bortezomib sensitized non-small cell lung cancer cells.

Histone deacetylase (HDAC) inhibitors have been proven to be effective therapeutic agents to kill cancer cells through inhibiting HDAC activity or altering the structure of chromatin. We recently reported that chemotherapy by the HDAC inhibitor, romidepsin activates the anti- apoptotic transcription factor NF-κB in A549 non-small cell lung cancer (NSCLC) cells and fails to induce significant levels of apoptosis. We also demonstrated that NF-κB inhibition with proteasome inhibitor bortezomib enhanced HDAC inhibitor induced mitochondrial injury and sensitize A549 NSCLC cells to apoptosis through the generation of reactive oxygen species. In this study, we investigate whether combined treatment with romidepsin and bortezomib would induce apoptosis in A549 NSCLC cells by activating cell cycle arrest, enhanced generation of p21 and p53, down-regulation of matrix metalloproteinases (MMPs) 2,9 also altering the acetylation status of histone proteins. Our data show that combination of romidepsin and bortezomib caused cell cycle arrest at Sub G0-G1 transition, up-regulation of cell cycle protein p21 and tumour suppressor protein p53. In addition, romidepsin down-regulated the expression of MMP-2,9 and hyperacetylation of histone H3 and H4 in bortezomib sensitised A549 NSCLC cells. From this study we concluded that romidepsin and bortezomib cooperatively inhibit A549 NSCLC cell proliferation by altering the histone acetylation status, expression of cell cycle regulators and MMPs. Romidepsin along with bortezomib might be an effective treatment approach for A549 NSCLC cells.