Explore the vast range of titles available.

Resveratrol (RV) is a natural component of red wine and grapes that has been shown to be a potential chemopreventive and anticancer agent. However, the molecular mechanisms underlying RV's anticancer and chemopreventive effects are incompletely understood. Here we show that RV treatment inhibits the clonogenic growth of non-small cell lung cancer (NSCLC) cells in a dose-dependent manner. Interestingly, the tumor-suppressive effect of low dose RV was not associated with any significant changes in the expression of cleaved PARP and activated caspase-3, suggesting that low dose RV treatment may suppress tumor cell growth via an apoptosis-independent mechanism. Subsequent studies reveal that low dose RV treatment induces a significant increase in senescence-associated β-galactosidase (SA-β-gal) staining and elevated expression of p53 and p21 in NSCLC cells. Furthermore, we show that RV-induced suppression of lung cancer cell growth is associated with a decrease in the expression of EF1A. These results suggest that RV may exert its anticancer and chemopreventive effects through the induction of premature senescence. Mechanistically, RV-induced premature senescence correlates with increased DNA double strand breaks (DSBs) and reactive oxygen species (ROS) production in lung cancer cells. Inhibition of ROS production by N-acetylcysteine (NAC) attenuates RV-induced DNA DSBs and premature senescence. Furthermore, we show that RV treatment markedly induces NAPDH oxidase-5 (Nox5) expression in both A549 and H460 cells, suggesting that RV may increase ROS generation in lung cancer cells through upregulating Nox5 expression. Together, these findings demonstrate that low dose RV treatment inhibits lung cancer cell growth via a previously unappreciated mechanism, namely the induction of premature senescence through ROS-mediated DNA damage.

Background Nicotinamide N -methyltransferase (NNMT) is overexpressed in various human tumors and involved in the development and progression of several carcinomas. In breast cancer, NNMT was found to be overexpressed in several cell lines. However, the clinical relevance of NNMT in breast cancer is not yet clear. Methods NNMT expression in breast carcinoma was examined by immunohistochemistry, and then, its relationship with patient clinicopathological characteristics was analyzed. The effects of NNMT on chemoresistance in breast cancer cells were assessed by cell viability, colony formation, and apoptosis assay. The NNMT, SIRT1, p53, and acetyl-p53 proteins, which are involved in NNMT-related chemoresistance, were examined by Western blotting. The SIRT1 mRNA was examined by real-time PCR, and its activity was measured by using the SIRT1 deacetylase fluorometric reagent kit. Results NNMT expression was significantly higher (53.9%) in breast carcinoma than in paracancerous tissues (10.0%) and breast hyperplasia (13.3%). A high level of NNMT expression correlated with poor survival and chemotherapy response in breast cancer patients who received chemotherapy. Ectopic overexpression of NNMT significantly inhibited the apoptotic cell death and suppression of colony formation induced by adriamycin and paclitaxel. Mechanistic studies revealed that NNMT overexpression increased SIRT1 expression and promoted its activity. Either inhibition of SIRT1 by EX527 or knockdown of SIRT1 by siRNA could reverse NNMT-mediated resistance to adriamycin and paclitaxel, which suggests that SIRT1 plays a critical role in NNMT-related chemoresistance in breast cancer. Conclusions The results of this study demonstrate a novel correlation between the NNMT expression level and patient survival, suggesting that NNMT has the potential to become a new prognostic biomarker to predict the treatment outcomes of the clinical chemotherapy in breast cancer. Moreover, targeting NNMT or downstream SIRT1 may represent a new therapeutic approach to improve the efficacy of breast cancer chemotherapy.

2,2'-diselenyldibenzoic acid (DSBA) is a chemical probe produced to explore the pharmacological properties of diphenyldiselenide-derived agents with seleno-hormetic activity undergoing preclinical development. The present study was designed to verify in vivo the drug's properties and to determine mechanistically how these may mediate the protection of tissues against stress conditions, exemplified by ionizing radiation induced damage in mouse bone marrow. In murine bone marrow hematopoietic cells, the drug initiated the activation of the Nrf2 transcription factor resulting in enhanced expression of downstream stress response genes. This type of response was confirmed in human liver cells and included enhanced expression of glutathione S-transferases (GST), important in the metabolism and pharmacological function of seleno-compounds. In C57 BL/6 mice, DSBA prevented the suppression of bone marrow hematopoietic cells caused by ionizing radiation exposure. Such in vivo prevention effects were associated with Nrf2 pathway activation in both bone marrow cells and liver tissue. These findings demonstrated for the first time the pharmacological properties of DSBA in vivo, suggesting a practical application for this type of Se-hormetic molecules as a radioprotective and/or prevention agents in cancer treatments.

Epidemiological studies have identified an association between the exposure to neurotoxic heavy metals such as cadmium (Cd) and an increased risk for Alzheimer's disease (AD). However, the cellular and molecular mechanisms by which Cd or lead (Pb) exposure affects AD pathogenesis and progression are largely unknown. The goal of this study was to determine how Cd and Pb exposure impact cognitive function and AD progression using the 5xFAD transgenic mouse model of AD. Juvenile (5-weeks old) 5xFAD mice were challenged with 0.2% Pb or 0.002% Cd in drinking water for 6 weeks to model chronic environmental exposures. Y-maze tests were performed to assess spatial memory and learning ability. The Open Field Maze test was employed to examine anxiety-like behaviors. Senescent cells were determined using senescence-associated β-galactosidase staining. Quantitative RT-PCR assays were performed to measure expression levels of senescence markers and senescence-associated secretory phenotype (SASP) related cytokines. Immunofluorescence and confocal microscopy were used to analyze senescent cells and neuroinflammation markers in brain tissues. Cd and Pb both can accelerate the pace of amyloid beta (Aβ) plaque formation and the decline of cognitive functions in 5xFAD mice. Even at a 100-fold lower dose, chronic Cd exposure causes a greater level of Aβ deposition and cognitive deficits than Pb does, indicating that Cd is more potent than Pb in exacerbating AD progression. Mechanistically, we found that the increased expression of the p16 senescence marker was more pronounced in the hippocampus of Cd-exposed mice compared to those treated with Pb. Notably, Cd upregulates the expression of the SASP marker IL-6 preferentially in the hippocampus over the cortex, suggesting a spatial difference in Cd-induced increase in neuroinflammation. Furthermore, in vitro mechanistic studies reveal that Cd exposure induces premature senescence in human microglial cells, and senescent microglia release high levels of IL-6, a major modulator of neuroinflammation. Our studies demonstrate that chronic exposure to Cd or Pb can exacerbate cognitive deficits and AD progression in 5xFAD mice. Mechanistically, we discovered that Cd exposure-induced acceleration of AD progression was associated with increased levels of senescent cell burden and neuroinflammation in the hippocampus.

The accumulation of amyloid beta (Aβ) plaques in the brain is a hallmark of Alzheimer’s disease (AD) pathology. Microglial activation-mediated neuroinflammation has been implicated in the pathogenesis of AD and the expression levels of interleukin-6 (IL-6) were increased in the brains of AD patients. However, the mechanisms by which IL-6 expression is regulated in human microglia are incompletely understood. Here, we show that Aβ 1-40 oligomers (Aβ 40 ) dose-dependently stimulate IL-6 expression in HMC3 human microglial cells. Treatment with Aβ 40 promotes the transcription of IL-6 and tumor necrosis factor α (TNFα) mRNAs in both HMC3 and THP-1 cells. Mechanistic studies reveal that Aβ 40 -induced increase of IL-6 secretion is associated with the activation of p38 mitogen-activated protein kinase (p38 MAPK). Inhibition of p38 MAPK by BIRB 796 or SB202190 abrogates Aβ 40 -induced increase of IL-6 production. Through analyzing brain specimens, we found that the immunoreactivity for IL-6 and phosphorylated (the activated form) p38 MAPK was markedly higher in microglia of AD patients than in age-matched control subjects. Moreover, our studies identified the co-localization of IL-6 with phosphorylated p38 MAPK in microglia in the cortices of AD patients. Taken together, these results indicate that p38 MAPK is a major regulator of Aβ-induced IL-6 production in human microglia, which suggests that targeting p38 MAPK may represent a new approach to ameliorate Aβ accumulation-induced neuroinflammation in AD.

Radiotherapy is used in >50% of patients during the course of cancer treatment both as a curative modality and for palliation. However, radioresistance is a major obstacle to the success of radiation therapy and contributes significantly to tumor recurrence and treatment failure, highlighting the need for the development of novel radiosensitizers that can be used to overcome tumor radioresistance and, thus, improve the efficacy of radiotherapy. Previous studies indicated that resveratrol (RV) may sensitize tumor cells to chemotherapy and ionizing radiation (IR). However, the mechanisms by which RV increases the radiation sensitivity of cancer cells have not been well characterized. Here, we show that RV treatment enhances IR-induced cell killing in non-small cell lung cancer (NSCLC) cells through an apoptosis-independent mechanism. Further studies revealed that the percentage of senescence-associated β-galactosidase (SA-β-gal)-positive senescent cells was markedly higher in cells treated with IR in combination with RV compared with cells treated either with IR or RV alone, suggesting that RV treatment enhances IR-induced premature senescence in lung cancer cells. Comet assays demonstrate that RV and IR combined treatment causes more DNA double-strand breaks (DSBs) than IR or RV treatment alone. DCF-DA staining and flow cytometric analyses demonstrate that RV and IR combined treatment leads to a significant increase in ROS production in irradiated NSCLC cells. Furthermore, our investigation show that inhibition of ROS production by N-acetyl-cysteine attenuates RV-induced radiosensitization in lung cancer cells. Collectively, these results demonstrate that RV-induced radiosensitization is associated with significant increase of ROS production, DNA-DSBs and senescence induction in irradiated NSCLC cells, suggesting that RV treatment may sensitize lung cancer cells to radiotherapy via enhancing IR-induced premature senescence.

Background Many humanized angiotensin-converting enzyme 2 ( ACE2 ) mouse models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection do not replicate human ACE2 protein expression and thus exhibit pathology infrequently observed in humans. To address this limitation, we designed and characterized a fully humanized ACE2 (h ACE2 ) mouse by replacing all exons/introns of the mouse Ace2 locus with human DNA comprising the entire ACE2 gene and an upstream long noncoding RNA (LncRNA). Results Compared to the popular Keratin18 ACE2 ( KRT18-ACE2 , K18 ) mouse model of SARS-CoV-2 infection, h ACE2 mice displayed a similar tissue expression profile of ACE2 as that seen in human tissues. Further, h ACE2 mice showed comparable blood pressure, angiotensin II metabolism, and renal cortical transcriptome as wild-type mice. Intranasal infection of K18 mice with the beta variant of SARS-CoV-2 resulted in high viral replication and inflammation of the lung and brain, weight loss, and compassionate euthanasia five days post-infection (PI). Similarly infected h ACE2 mice displayed viral replication and inflammation in the lung (but not in brain), sustained weight, and 100% survival up to 12 days PI, with clear evidence of acquired immunity. CRISPR-mediated disruption of the upstream LncRNA caused minimal effects on ACE2 mRNA and protein. Conclusions The h ACE2 model offers a more accurate approach to studying mechanisms underlying tissue-restricted expression of ACE2 , elucidating noncoding sequence variants and an upstream LncRNA, and defining pathways relevant to human disease and associated co-morbidities.

Background Leukemias driven by activated, chimeric FGFR1 kinases typically progress to AML which have poor prognosis. Mouse models of this syndrome allow detailed analysis of cellular and molecular changes occurring during leukemogenesis. We have used these models to determine the effects of leukemia development on the immune cell composition in the leukemia microenvironment during leukemia development and progression. Methods Single cell RNA sequencing (scRNA-Seq) was used to characterize leukemia associated neutrophils and define gene expression changes in these cells during leukemia progression. Results scRNA-Seq revealed six distinct subgroups of neutrophils based on their specific differential gene expression. In response to leukemia development, there is a dramatic increase in only two of the neutrophil subgroups. These two subgroups show specific gene expression signatures consistent with neutrophil precursors which give rise to immature polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Analysis of gene expression in these precursor cells identified pathways that were specifically upregulated, the most pronounced of which involved matrix metalloproteinases Mmp8 and Mmp9 , during leukemia progression. Pharmacological inhibition of MMPs using Ilomastat preferentially restricted in vitro migration of neutrophils from leukemic mice and led to a significantly improved survival in vivo, accompanied by impaired PMN-MDSC recruitment. As a result, levels of T-cells were proportionally increased. In clinically annotated TCGA databases, MMP8 was shown to act as an independent indicator for poor prognosis and correlated with higher neutrophil infiltration and poor pan-cancer prognosis. Conclusion We have defined specific leukemia responsive neutrophil subgroups based on their unique gene expression profile, which appear to be the precursors of neutrophils specifically associated with leukemia progression. An important event during development of these neutrophils is upregulation MMP genes which facilitated mobilization of these precursors from the BM in response to cancer progression, suggesting a possible therapeutic approach to suppress the development of immune tolerance.

The development of FGFR1-driven stem cell leukemia and lymphoma syndrome (SCLL) in mouse models is accompanied by an increase in highly heterogenous myeloid derived suppressor cells (MDSCs), which promote immune evasion. To dissect this heterogeneity, we used a combination of CyTOF and scRNA-Seq to define the phenotypes and genotypes of these MDSCs. CyTOF demonstrated increased levels of circulating macrophages in the peripheral blood of leukemic mice, and flow cytometry demonstrated that these macrophages were derived from Ly6CHi M-MDSC as well as the Ly6CInt and Ly6CLow monocytic populations. Consistently, scRNA-Seq analysis demonstrated the accumulation of non-classical monocytes (ncMono) during leukemia progression, which also express macrophage markers. These leukemia-induced macrophages show continuous transcriptional reprogramming during leukemia progression, with the upregulation of cellular stress response genes Hspa1a and Hspa1b and inflammation-related gene Nfkbia. Trajectory analysis revealed a transition from classical monocytes (cMono) to ncMono, and potential genes orchestrating this transition process have been identified. Furthermore, T-cell suppression assays demonstrated the immune suppressive abilities of leukemia-induced circulatory macrophages. Targeting these macrophages with the GW2580 CSF1R inhibitor leads to restored immune surveillance and improved survival. Overall, we demonstrate that circulating macrophages are responsible, at least in part, for the immune suppression in SCLL leukemia models, and targeting macrophages in this system improves the survival of leukemic mice.

Abnormal activation of the mammalian target of rapamycin (mTOR) signaling pathway has been observed in a variety of human cancers. Therefore, targeting of the mTOR pathway is an attractive strategy for cancer treatment and several mTOR inhibitors, including AZD8055 (AZD), a novel dual mTORC1/2 inhibitor, are currently in clinical trials. Although bone marrow (BM) suppression is one of the primary side effects of anticancer drugs, it is not known if pharmacological inhibition of dual mTORC1/2 affects BM hematopoietic stem and progenitor cells (HSPCs) function and plasticity. Here we report that dual inhibition of mTORC1/2 by AZD or its analogue (KU-63794) depletes mouse BM Lin−Sca-1+c-Kit+ cells in cultures via the induction of apoptotic cell death. Subsequent colony-forming unit (CFU) assays revealed that inhibition of mTORC1/2 suppresses the clonogenic function of hematopoietic progenitor cells (HPCs) in a dose-dependent manner. Surprisingly, we found that dual inhibition of mTORC1/2 markedly inhibits the growth of day-14 cobblestone area-forming cells (CAFCs) but enhances the generation of day-35 CAFCs. Given the fact that day-14 and day-35 CAFCs are functional surrogates of HPCs and hematopoietic stem cells (HSCs), respectively, these results suggest that dual inhibition of mTORC1/2 may have distinct effects on HPCs versus HSCs.