Silencing Sirtuin 6 induces cell cycle arrest and apoptosis in non-small cell lung cancer cell lines.

Sirtuins (SIRT1-7), are NAD-dependent deacetylases and ADP-ribosyl transferases, plays a major part in carcinogenesis. The previous report suggests that in cancer, sirtuins gained tremendous interest and critical regulators of the unusual processes. In carcinogenesis, sirtuins possess either tumor suppressor or promoter. However, in lung cancer condition the studies of sirtuins are less studied. Hence, this designed study investigates the impact of multifaceted sirtuins in NSCLC cells. We evaluated the mRNA and protein expressions of sirtuins by RTPCR and western blot. We found SIRT6 significantly overexpressed in NCI-H520, A549, and NCI-H460 compared with the normal BEAS-2B cell line. Silencing of SIRT6 by siRNA in NSCLC cells caused activation of p53/p21 mediated inhibition of cell proliferation leading to arrest in cell cycle and apoptosis induction. Our results implied that SIRT6 is a tumor promoter in NSCLC development, progression, and regulation. The silencing of SIRT6 to be a novel therapy for lung cancer.

Annona muricata assisted biogenic synthesis of silver nanoparticles regulates cell cycle arrest in NSCLC cell lines.

With plenteous accessible therapeutics, lung cancer endures a preeminent cause of the worldwide fatality. Apart from medical advancements, various plant parts are still used to treat cancer based on proven tradition. The present study focuses on analysing the anticancer efficacy of silver nanoparticles coupled with the aqueous leaf extract of Annona muricata. Nanoparticles play a momentous role in drug delivery due to their size and high surface to volume ratio and are with fewer side effect when phytofabricated. Annona muricata aqueous leaf extract mediated silver nanoparticles were characterized using UV visible spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction and Zeta-sizer. Their antiproliferative potency was analysed by studying the mRNA and protein expressions of various apoptotic, anti-apoptotic and cell cycle regulatory genes. In addition, the cell cycle regulation was further confirmed using flow cytometry. The nanoparticles were found to be spherical shaped crystals with 80 ± 6.3 nm as average size and 6 µg/ml as inhibitory concentration 50 (IC50) on A549 human lung cancer cell line. It was observed that the nanoparticles efficiently induced apoptotic protein expression with a simultaneous suppression of anti-apoptotic protein. The results demonstrate activation of an intertwined intrinsic apoptotic pathway via caspases and the death receptors. The observations infer that the nanoparticles show excellent anticancer efficacy than the crude extract of Annona muricata leaves. Hence these nanoparticles would be a promising adjuvant for treating non- small cell lung cancer.

Marine steroid derived from Acropora formosa enhances mitochondrial-mediated apoptosis in non-small cell lung cancer cells.

p53 pathway has been revealed to mediate cellular stress responses and trigger DNA repair, cell cycle arrest, senescence, and apoptosis. We isolated 2-ethoxycarbonyl-2-ß-hydroxy-A-nor-cholest-5-ene-4one (ECHC) from butanol extracts of scleractinian coral Acropora formosa and reported its potential antioxidant and antimicrobial activity as well as less toxicity against zebrafish Danio rerio. In the present study, we intend to explore p53-mediated apoptosis pathway enhanced by ECHC in A549 human non-small cell lung cancer cell lines. This report shows that ECHC increases ROS generation and sensitizes mitochondrial membrane that leads to the release of cytochrome C (Cyto C) into cytosol. Further, ECHC decreases the expression of antiapoptotic genes such as TNF-α, IL-8, Bcl2, MMP2, and MMP9 which are actively involved in cancer cell proliferation, invasion, and metastasis etc. It also increases the expression of apoptotic genes Cyto C, Bax, and p21, which are responsible for cell cycle arrest and cell death. The tumor suppressor p53 was also observed to be upregulated during ECHC treatment in untransformed cells and was more likely to result in cell cycle arrest, senescence, and apoptosis. Finally, ECHC also down regulates the expression of caspase-9 and caspase-3 which are the death stage of intrinsic apoptosis. Our findings suggested that ECHC enhances ROS generation and mitochondrial sensitization determines the threshold for irreversible p53-mediated intrinsic apoptosis pathway.

Targeting DNA Repair and Survival Signaling in Diffuse Intrinsic Pontine Gliomas to Prevent Tumor Recurrence.

Therapeutic resistance remains a major obstacle to successful clinical management of diffuse intrinsic pontine glioma (DIPG), a high-grade pediatric tumor of the brain stem. In nearly all patients, available therapies fail to prevent progression. Innovative combinatorial therapies that penetrate the blood-brain barrier and lead to long-term control of tumor growth are desperately needed. We identified mechanisms of resistance to radiotherapy, the standard of care for DIPG. On the basis of these findings, we rationally designed a brain-penetrant small molecule, MTX-241F, that is a highly selective inhibitor of EGFR and PI3 kinase family members, including the DNA repair protein DNA-PK. Preliminary studies demonstrated that micromolar levels of this inhibitor can be achieved in murine brain tissue and that MTX-241F exhibits promising single-agent efficacy and radiosensitizing activity in patient-derived DIPG neurospheres. Its physiochemical properties include high exposure in the brain, indicating excellent brain penetrance. Because radiotherapy results in double-strand breaks that are repaired by homologous recombination (HR) and non-homologous DNA end joining (NHEJ), we have tested the combination of MTX-241F with an inhibitor of Ataxia Telangiectasia Mutated to achieve blockade of HR and NHEJ, respectively, with or without radiotherapy. When HR blockers were combined with MTX-241F and radiotherapy, synthetic lethality was observed, providing impetus to explore this combination in clinically relevant models of DIPG. Our data provide proof-of-concept evidence to support advanced development of MTX-241F for the treatment of DIPG. Future studies will be designed to inform rapid clinical translation to ultimately impact patients diagnosed with this devastating disease.

CREB activation drives acinar to ductal reprogramming and promote pancreatic cancer progression in animal models of alcoholic chronic pancreatitis.

BACKGROUND AND AIMS: In vivo induction of alcoholic chronic pancreatitis (ACP) causes significant acinar damage, increased fibroinflammatory response, and heightened activation of cyclic response element binding protein 1 (CREB) when compared with alcohol (A) or chronic pancreatitis (CP) mediated pancreatic damage. However, the study elucidating the cooperative interaction between CREB and the oncogenic Kras G12D/+ (Kras*) in promoting pancreatic cancer progression with ACP remains unexplored. METHODS: Experimental ACP induction was established in multiple mouse models, followed by euthanization of the animals at various time intervals during the recovery periods. Tumor latency was determined in these mice cohorts. Here, we established CREB deletion (Creb fl/fl ) in Ptf1a CreERTM/+ ;LSL-Kras G12D+/-(KC) genetic mouse models (KCC-/-). Western blot, phosphokinase array, and qPCR were used to analyze the pancreata of Ptf1a CreERTM+/-, KC and KCC -/- mice. The pancreata of ACP-induced KC mice were subjected to single-cell RNA sequencing (scRNAseq). Further studies involved conducting lineage tracing and acinar cell explant cultures. RESULTS: ACP induction in KC mice had detrimental effects on the pancreatic damage repair mechanism. The persistent existence of acinar cell-derived ductal lesions demonstrated a prolonged state of hyperactivated CREB. Persistent CREB activation leads to acinar cell reprogramming and increased pro-fibrotic inflammation in KC mice. Acinar-specific Creb ablation reduced advanced PanINs lesions, hindered tumor progression, and restored acinar cell function in ACP-induced mouse models. CONCLUSIONS: Our findings demonstrate that CREB cooperates with Kras* to perpetuate an irreversible ADM and PanIN formation. Moreover, CREB sustains oncogenic activity to promote the progression of premalignant lesions toward cancer in the presence of ACP.

Histone H3 K27M-mediated regulation of cancer cell stemness and differentiation in diffuse midline glioma.

Therapeutic resistance remains a major obstacle to preventing progression of H3K27M-altered Diffuse Midline Glioma (DMG). Resistance is driven in part by ALDH-positive cancer stem cells (CSC), with high ALDH1A3 expression observed in H3K27M-mutant DMG biopsies. We hypothesized that ALDH-mediated stemness and resistance may in part be driven by the oncohistone itself. Upon deletion of H3K27M, ALDH1A3 expression decreased dramatically and was accompanied by a gain in astrocytic marker expression and a loss of neurosphere forming potential, indicative of differentiation. Here we show that the oncohistone regulates histone acetylation through ALDH1A3 in a Wnt-dependent manner and that loss of H3K27M expression results in sensitization of DMGs to radiotherapy. The observed elevated Wnt signaling in H3K27M-altered DMG likely stems from a dramatic suppression of mRNA and protein expression of the Wnt inhibitor EYA4 driven by the oncohistone. Thus, our findings identify EYA4 as a bona fide tumor suppressor in DMG that upon suppression, results in aberrant Wnt signaling to orchestrate stemness and differentiation. Future studies will explore whether overexpression of EYA4 in DMG can impede growth and invasion. In summary, we have gained mechanistic insight into H3K27M-mediated regulation of cancer stemness and differentiation, which provides rationale for exploring new therapeutic targets for DMG.

Structural characterization and anticancer activity (MCF7 and MDA-MB-231) of polysaccharides fractionated from brown seaweed Sargassum wightii.

The purpose of this study was to investigate the anticancer activity of polysaccharides from brown seaweed Sargassum wightii (SWP) on human breast cancer cells. Initially, two polysaccharide fractions (SWP1 and SWP2) were isolated and purified from the crude polysaccharides using DEAE-52 cellulose and Sephadex G-100 column chromatography. As a result, SWP1 was obtained with the yield of 21.48% was characterized using chemical analysis, GC-MS, 1H NMR and 13C NMR. The chemical composition of the extracted polysaccharide contains a neutral polysaccharide with a high total sugar content and low protein, phenol and flavonoid content. GC-MS analysis revealed the presence of galactofuranose and arabinose and NMR spectra shows the presence of ß-galactose signals. Anticancer activity shows that the polysaccharides significantly reduce the proliferation of breast cancer cells (MCF7 and MDA-MB-231) in a dose-dependent manner. Further, polysaccharides induced the apoptosis in the breast cancer cells by increasing ROS generation, cleaving mitochondrial membrane and nuclei damage. Finally, polysaccharides increased the activity of caspase 3/9, thus leads to apoptosis of breast cancer. Together, polysaccharides from S. wightii could be a new source of natural anticancer agent against breast cancer with potential value in the manufacturing supplements and drugs.