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Abstract: Background: There is increasing evidence suggesting the role of free radicals in bone resorption and bone loss. Ovariectomized rats have been used as the animal model for the study of osteoporosis. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. Even though, there are studies portraying the role of free radicals in bone loss, the defense mechanism adapted by bone in ovariectomized animals remains obscure. We investigated the impact of ovariectomy (OVX) on the bone antioxidant system in rats. Methods: Sixty days after bilateral OVX, the rats were killed and the femora were removed, the tissue homogenates were made and used for the estimation of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S transferase (GST), lipid peroxidation (LPO) and hydrogen peroxide (H2O2). Results: The levels of LPO and H2O2 were increased and enzymatic antioxidants like SOD, GPx, GST were decreased in ovariectomized animals when compared to sham-operated control rats. The calculated correlation coefficient demonstrated strong correlation (0.905) between the production of H2O2 and LPO in the femur bone. A strong inverse (−0.945) correlation was observed between H2O2 production and SOD activity. Conclusions: OVX induces oxidative stress in the femur bone of rats. [Copyright &y& Elsevier]

Background: Development of resistance upon exposure to small doses of ionizing radiation followed by higher doses is known as radiation-induced adaptive response (RIAR). Traditionally, the induction of the RIAR phenomenon at the cellular level has been examined in cell lines, animal models, and epidemiological studies where people live in high natural background radiation. Summary: The primary intention of the earlier studies was to corroborate the existence of RIAR and the mechanism involved in mediating the response surveyed by exposure to a low dose of radiation (<500 mGy) as priming dose toward the radiation protection point of view. However, the investigation has shifted the focus to understand the relevance of this phenomenon at clinically relevant set-ups (high doses in the order of Gy) and can be exploited during radiotherapy as RIAR is considered a mechanism for the development of radioresistance. Although the knowledge of molecular mechanisms at the cellular level has evolved significantly in multi-fractionated radiotherapy regimes, its relevance in developing radioresistance at low doses remains elusive. The authors recapitulate the existing knowledge on RIAR at cellular levels, specifically after low-dose exposure as an adaptive dose, and discussed its potential implications in clinical radiotherapy outcomes. Key Messages: Recent studies have contributed to understand the signaling molecules, pathways, and inhibitors to mitigate RIAR-mediated radiation resistance and persistent radio-tolerance at the cellular level. Monitoring the disease progression in tumor samples or liquid biopsies before, during, and after therapy with suitable biomarkers has been proposed as a strategy to translate the phenomena into clinical scenario. [ABSTRACT FROM AUTHOR]

The present study was designed to establish the epigenetic mechanisms by which lactational exposure to PCBs affects the Leydig cell function in progeny rats. The lactating dams were oral gavaged with different doses of PCBs [1, 2 and 5 mg/kg or corn oil ] and Leydig cells were isolated from the testes of progeny rats at postnatal day (PND) 60. We assessed the expression of transcription factors regulating steroidogenic machinery and the promoter methylation of LHR and AR in the Leydig cells. Our results confirmed hypermethylation of SF‐1, Sp1/3, LHR and AR genes. There was a significant reduction in the gene expression of SF‐1 and Sp1. The mRNA expression of Sp3 was decreased. Interestingly, there was an increased gene expression levels of DNA methyltransferases (Dnmts) (Dnmt1, Dnmt3a/b and Dnmt3l) and unaltered histone deacetylase‐1 (Hdac‐1). Furthermore, increased percentage of 5‐methylcytosine was observed in PCBs exposed Leydig cells. Taken together, our findings suggest that promoter hypermethylation of SF‐1, Sp1/3, LHR and AR could have led to transcriptional repression of these genes in Leydig cells. In conclusion, our study demonstrates that lactational exposure to PCBs caused epigenetic changes in the Leydig cells which could have impaired the Leydig cell function in progeny (PND60) rats. [ABSTRACT FROM AUTHOR]

Chemotherapy and radiotherapy resistance are major obstacles in the long-term efficacy of head and neck squamous cell carcinoma (HNSCC) treatment. Secondhand smoke (SHS) exposure is common and has been proposed as an independent predictor of HNSCC recurrence and disease-free survival. However, the underlying mechanisms responsible for these negative patient outcomes are unknown. To assess the effects of SHS exposure on cisplatin efficacy in cancer cells, three distinct HNSCC cell lines were exposed to sidestream (SS) smoke, the main component of SHS, at concentrations mimicking the nicotine level seen in passive smokers' saliva and treated with cisplatin (0.01–100 µM) for 48 h. Compared to cisplatin treatment alone, cancer cells exposed to both cisplatin and SS smoke extract showed significantly lower cisplatin-induced cell death and higher cell viability, IC50, and indefinite survival capacity. However, SS smoke extract exposure alone did not change cancer cell viability, cell death, or cell proliferation compared to unexposed control cancer cells. Mechanistically, exposure to SS smoke extract significantly reduced the expression of cisplatin influx transporter CTR1, and increased the expression of multidrug-resistant proteins ABCG2 and ATP7A. Our study is the first to document that exposure to SHS can increase cisplatin resistance by altering the expression of several proteins involved in multidrug resistance, thus increasing the cells' capability to evade cisplatin-induced cell death. These findings emphasize the urgent need for clinicians to consider the potential role of SHS on treatment outcomes and to advise cancer patients and caregivers on the potential benefits of avoiding SHS exposure. [ABSTRACT FROM AUTHOR]

Fusion genes are key cancer driver genes that can be used as potential drug targets in precision therapies, and they can also serve as accurate diagnostic and prognostic biomarkers. The fusion genes can cause microRNA (miRNA/miR) aberrations in many types of cancer. Nevertheless, whether fusion genes incite miRNA aberrations as one of their many critical oncogenic functionalities for driving carcinogenesis needs further investigation. Recent discoveries of miRNA genes that are present within the regions of genomic rearrangements that initiate fusion gene-based intronic miRNA dysregulation have brought the fusion genes into the limelight and revealed their unexplored potential in the field of cancer biology. Fusion gene-based 'promoter-switch' event aberrantly activate the miRNA-related upstream regulatory signals, while fusion-based coding region alterations disrupt the original miRNA coding loci. Fusion genes can potentially regulate the miRNA aberrations regardless of the protein-coding capability of the resultant fusion transcript. Studies on out-of-frame fusion and nonrecurrent fusion genes that cause miRNA dysregulation have attracted the attention of researchers on fusion genes from an oncological perspective and therefore could have potential implications in cancer therapies. This review will provide insights into the role of fusion genes and miRNAs, and their possible interrelationships in cancer. [ABSTRACT FROM AUTHOR]

Background Mainstream (MS) smoke, the main smoke inhaled by active smokers, and sidestream (SS) smoke, the main component of secondhand smoke, induce a wide range of DNA lesions. Owing to technical limitations, the in vivo levels of tobacco-induced DNA damage are unknown. Recently, the authors developed a highly sensitive primer-anchored DNA damage detection assay (PADDA) to quantify endogenous and induced DNA damage. Purpose To quantify the in vivo levels of DNA damage induced by MS and SS smoke extracts in human cells using PADDA and define the strand-specific patterns of DNA damage and repair following exposure to diverse doses of MS and SS smoke. Methods Human epithelial cells were exposed to escalating doses of hydrogen peroxide (H 2 O 2 ), MS, or SS smoke. TP53 gene DNA damage was quantified using PADDA at various time points. DNA double-strand breaks were detected by immunofluorescence analysis of phosphorylated histone H2AX (γ-H2AX). Cell viability was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Data were collected and analyzed by t -test in 2012–2014. Results A dose-dependent increase in DNA damage was detected in vivo with increasing doses of H 2 O 2 , MS, and SS smoke. Even 1 hour of exposure to very low doses of MS or SS smoke resulted in significant DNA damage ( p <0.01). MS and SS smoke induced distinctive strand-specific patterns of DNA damage and DNA repair kinetics. Conclusions Very low concentrations of MS and SS smoke induce significant DNA damage in human cells. Application of PADDA to population studies has major potential to establish biomarkers of susceptibility to tobacco-induced diseases. [ABSTRACT FROM AUTHOR]

The present study was aimed to determine the effects of lactational exposure of PCBs (Aroclor 1254) on Leydig cellular steroidogenesis in F 1 progeny rats. Lactating dams were orally treated by gavage with different doses of PCBs (1, 2 and 5 mg/kg b.wt./day). Male progenies were sacrificed on PND60. Our results demonstrated that exposure to PCBs decreased the body weight, testis weight and anogenital distance (AGD) index in the F 1 progeny rats. Importantly, PCBs exposure reduced the serum levels of LH, testosterone and estradiol. Interestingly, PCBs caused a decrease in the Leydig cell population along with decreased activities of steroidogenic enzymes 3β- and 17β-HSD. Additionally, we observed a significant decrease in LHR, SR-B1, StAR protein, Cyp11a1, 3β-HSD, Cyp17a1, 17β-HSD, 5α-reductase, Cyp19a1 and AR gene expression in the Leydig cells of progeny rats. In conclusion, our study demonstrates that lactational exposure of PCBs alters Leydig cellular steroidogenesis in the F 1 progeny rats. [ABSTRACT FROM AUTHOR]

Phthalates, a class of chemicals used as plasticizers, are economically important due to several industrial applications. Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly used phthalate plasticizer, and it has been described as a potent antiandrogen in males. In this study, lactating dams were exposed via oral gavage to corn oil (vehicle) and DEHP (1, 10, and 100 mg/kg body weight) from postnatal day 1 to 21, and the effects were evaluated in the ovary and uterus of F1 progeny. DEHP exposure significantly decreased the body weight and organ weight in a dose-dependent manner. Serum levels of estradiol, testosterone, and progesterone were decreased but anogenital distance was unaffected. The mRNA expressions of luteinizing hormone receptor, follicle-stimulating hormone receptor, androgen receptor, estrogen receptor (ERα and ERβ), progesterone receptor, peroxisome proliferator-activated receptor γ, 3β hydroxysteroid dehydrogenase, aromatase, and steroidogenic acute regulatory protein were altered in the ovary of F1 progeny rats. Our finding suggest that lactational exposure to DEHP has transgenerational effect on female reproductive system. [ABSTRACT FROM AUTHOR]

Research dealing with early diagnosis and efficient treatment in colon cancer to improve patient's survival is still under investigation. Chemotherapeutic agent result in high systemic toxicity due to their non‐specific actions on DNA repair and/or cell replication. Traditional medicine such as Lycopodium clavatum (LC) has been claimed to have therapeutic potentials against cancer. The present study focuses on targeted drug delivery of cationic liposomal nanoformulated LC (CL‐LC) in colon cancer cells (HCT15) and comparing the efficacy with an anti‐colon cancer drug, 7‐ethyl‐10‐hydroxy‐camptothecin (SN38) along with its nanoformulated form (CL‐SN38). The colloidal suspension of LC was made using thin film hydration method. The drugs were characterised using ultraviolet, dynamic light scattering, scanning electron microscopy, energy, dispersive X‐ray spectroscopy. Invitro drug release showed kinetics of 49 and 89% of SN38 and LC, whereas CL‐SN38 and CL‐LC showed 73 and 74% of sustained drug release, respectively. Studies on morphological changes, cell viability, cytotoxicity, apoptosis, cancer‐associated gene expression analysis of Bcl‐2, Bax, p53 by real‐time polymerase chain reaction and western blot analysis of Bad and p53 protein were performed. Nanoformulated LC significantly inhibited growth and increased the apoptosis of colon cancer cells indicating its potential anti‐cancer activity against colon cancer cells. [ABSTRACT FROM AUTHOR]

Background: Electronic cigarette (EC) aerosols contain unique compounds in addition to toxicants and carcinogens traditionally found in tobacco smoke. Studies are warranted to understand the public health risks of ECs. Objective: The aim of this study was to determine the genotoxicity and the mechanisms induced by EC aerosol extracts on human oral and lung epithelial cells. Methods: Cells were exposed to EC aerosol or mainstream smoke extracts and DNA damage was measured using the primer anchored DNA damage detection assay (q-PADDA) and 8-oxo-dG ELISA assay. Cell viability, reactive oxygen species (ROS) and total antioxidant capacity (TAC) were measured using standard methods. mRNA and protein expression were evaluated by RT-PCR and western blot, respectively. Results: EC aerosol extracts induced DNA damage in a dose-dependent manner, but independently of nicotine concentration. Overall, EC aerosol extracts induced significantly less DNA damage than mainstream smoke extracts, as measured by q-PADDA. However, the levels of oxidative DNA damage, as indicated by the presence of 8-oxo-dG, a highly mutagenic DNA lesion, were similar or slightly higher after exposure to EC aerosol compared to mainstream smoke extracts. Mechanistically, while exposure to EC extracts significantly increased ROS, it decreased TAC as well as the expression of 8-oxoguanine DNA glycosylase (OGG1), an enzyme essential for the removal of oxidative DNA damage. Conclusions: Exposure to EC aerosol extracts suppressed the cellular antioxidant defenses and led to significant DNA damage. These findings emphasize the urgent need to investigate the potential long-term cancer risk of exposure to EC aerosol for vapers and the general public. [ABSTRACT FROM AUTHOR]

The effect of gestational exposure to CrVI (occupational/environmental pollutant and target to Sertoli cells(SC)) was tested in a rat model during the testicular differentiation from the bipotential gonad may interrupt spermatogenesis by disrupting SC tight junctions(TJ) and it’s proteins and hormone receptors. Pregnant Wistar rats were exposed to 50/100/200 ppm CrVI through drinking water during embryonic days 9–14. On Postnatal day 120, testes were subjected to ion exchange chromatographic analysis and revealed increased level of CrIII in SCs and germ cells, serum and testicular interstitial fluid(TIF). Microscopic analyses showed seminiferous tubules atrophy and disruption of SC TJ, which also recorded decreased testosterone in TIF. mRNA and Protein expression analyses attested decreased level of Fshr, Ar , occludin and claudin-11 in SCs. Immunofluorescent detection revealed weak signal of TJ proteins. Taken together, we concluded that gestational exposure to CrVI interferes with the expression of SC TJ proteins due to attenuated expression of hormone receptors. [ABSTRACT FROM AUTHOR]

The cancer stem cell (CSC) hypothesis is an evolving oncogenesis concept. CSCs have a distinct ability to self-renew themselves and also give rise to a phenotypically diverse population of cells. Targeting CSCs represents a promising strategy for cancer treatment. Plant-derived compounds are potent in restricting the expansion of CSCs. DCLK1 has been already reported as a colon CSC specific marker. Nanoparticles can effectively inhibit multiple types of CSCs by targeting specific markers. We have synthesized DCLK1 functionalized folic acid conjugated hesperetin encapsulated chitosan nanoparticles (CFH-DCLK1), specifically to target CSCs. In this regard, we have performed proliferation assay, colony formation assay, cell migration assay, apoptosis assay, flow cytometry analysis, real-time RT- PCR and western blot analyses to determine the effect of CFH-DCLK1 and CFH nanoparticles in HCT116-colon cancer cells. In our study, we have determined the median inhibitory concentration (IC50) of CFH (47.8 µM) and CFH-DCLK1 (4.8 µM) nanoparticles in colon cancer cells. CFH-DCLK1 nanoparticles induced apoptosis and inhibited the migration and invasion of colon cancer cells. Real time PCR and western blot results have demonstrated that the treatment with CFH-DCLK1 nanoparticles significantly reduced the expression of CSC markers such as DCLK1, STAT1 and NOTCH1 compared to the CFH alone in HCT116 colon cancer cells. Finally, in the 3D spheroid model, CFH-DCLK1 nanoparticles significantly inhibited the colonosphere growth. Overall, our results highlight the effectiveness of CFH-DCLK1 nanoparticles in targeting the colon cancer cells and CSCs. This study would lead to the development of therapies targeting both cancer cells and CSCs simultaneously using nanoformulated drugs, which could bring changes in the current cancer treatment strategies. [Display omitted] • Cancer stem cells drive tumor initiation, metastasis, drug resistance and recurrence. • Nanoparticles can target cancer cells and cancer stem cells specifically. • Targeting doublecortin like kinase 1 can inhibit cancer stem cells self-renewal. • Folate receptor overexpression in cancer cells can be used for targeting therapy. [ABSTRACT FROM AUTHOR]

CUGBP2, a translation inhibitor, induces colon cancer cells to undergo apoptosis. Mcl-1, an antiapoptotic Bcl-2 family protein, interferes with mitochondrial activation to inhibit apoptosis. Here, we have determined the effect of CUGBP2 on Mcl-1 expression. We developed a HCUG2 cell line by stably expressing CUGBP2 in the HCT-116 colon cancer cells. HCUG2 cells demonstrate decreased levels of proliferation and increased apoptosis, compared with HCT-116 cells. Flow cytometry analysis demonstrated higher levels of cells in the G2-M phase. Western blot analyses demonstrated that there was decreased Bcl-2 and Mcl-1 protein but increased expression of Bax, cyclin B1, and Cdc2. Immunocytochemistry also demonstrated increased levels of cyclin B1 and Cdc2 in the nucleus of HCUG2 cells. However, there was colocalization of phosphorylated histone H3 with transferase- mediated dUTP nick-end labeling (TUNEL). Furthermore, immunostaining for α-tubulin demonstrated that there was disorganization of microtubules. These data suggest that CUGBP2 expression in HCUG2 cells induces the cells to undergo apoptosis during the G2-M phase of the cell cycle. We next determined the mechanism of CUGBP2- mediated reduction in Mcl-1 expression. Mcl-1 protein, but not Mcl-1 mRNA, was lower in HCUG2 cells, suggesting translation inhibition. CUGBP2 binds to Mcl-1 3′-untranslated region (3′-UTR) both in vitro and in HCUG2 cells. Furthermore, CUGBP2 increased the stability of both endogenous Mcl-1 and luciferase mRNA containing the Mcl-1 3′-UTR. However, luciferase protein expression from the luciferase-Mcl-1 3′-UTR mRNA was suppressed. Taken together, these data demonstrate that CUGBP2 inhibits Mcl-1 expression by inhibiting Mcl-1 mRNA translation, resulting in driving the cells to apoptosis during the G2 phase of the cell cycle. [ABSTRACT FROM AUTHOR]

CUG triplet repeat-binding protein 2 (CUGBP2) is a RNA-binding protein that regulates mRNA translation and modulates apoptosis. Here, we report the identification of two splice variants (termed variants 2 and 3) in cultured human intestinal epithelial cells and in mouse gastrointestinal tract. The variants are generated from alternative upstream promoters resulting in the inclusion of additional NH2-terminal residues. Although variant 2 is the predominant isoform in normal intestine, its expression is reduced, whereas variant 1 is overexpressed following γ-irradiation. All three variants bind cyclooxygenase-2 (COX-2) mRNA. However, only variant 1 inhibits the translation of the endogenous COX-2 mRNA and a chimeric luciferase mRNA containing the COX-2 3′untranslated region. Furthermore, whereas variant 1 is predominantly nuclear, variants 2 and 3 are predominantly cytoplasmic. These data imply that the additional amino acids affect CUGBP2 function. Previous studies have demonstrated that variant 1 induces intestinal epithelial cells to undergo apoptosis. However, in contrast to variant 1, the two novel variants do not affect proliferation or apoptosis of HCT116 cells. In addition, only variant 1 induced G2/M cell cycle arrest, which was overcome by prostaglandin E2. Moreover, variant 1 increased cellular levels of phosphorylated p53 and Bax and decreased Bcl2. Caspase-3 and -9 were also activated, suggesting the initiation of the intrinsic apoptotic pathway. Furthermore, increased phosphorylation of checkpoint kinase (Chk) 1 and Chk2 kinases and increased nuclear localization of Cdc2 and cyclin B1 suggested that cells were in mitotic transition. Taken together, these data demonstrate that cells expressing CUGBP2 variant 1 undergo apoptosis during mitosis, suggesting mitotic catastrophe. [ABSTRACT FROM AUTHOR]