Modulation of Arginase-2 mRNA Levels by ω-3 PUFAs and Aspirin in Asthmatic Human Lung Fibroblasts.

Airway remodeling (AR) increases disease severity, and morbidity of asthmatic patients by contributing to irreversible airflow obstruction and progressive declines in lung function. Arginase isoenzymes and the downstream enzymes ornithine decarboxylase (ODC) and ornithine aminotransferase (OAT) have been implicated in the hyperplastic and fibrotic changes of AR, respectively. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and resolvin metabolites have anti-AR effects, but whether they are mediated through the arginase pathway is unclear. Our study intended to determine the effects of the ω-3 PUFAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), resolvin D1 (RvD1), TH1 cytokines, acetylsalicylic acid (ASA), cAMP, and dexamethasone (DEX) on the expression of arginase isoenzymes arginase 1 (ARG1) and arginase 2 (ARG2), ODC, and OAT in human lung fibroblasts (HLF) from normal (NHLF) and diseased (DHLF) asthmatic donors using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). Our data showed that EPA and EPA+DHA downregulated ARG2 mRNA 2-fold in both types of HLF. DHA, RvD1, and DEX did not alter mRNA levels for any of the genes studied. EPA lowered the ARG2 protein levels in DHLF, but did not affect those levels in NHLF. ASA upregulated ARG2 mRNA 5-fold and 7-fold in NHLF and DHLF, respectively, TH1 cytokines downregulated ARG2, ODC, and OAT mRNA in DHLF 10-fold, 2-fold, and 2.5-fold, respectively, and cAMP downregulated ARG2 mRNA 2-fold in DHLF. These results are the first to show a direct effect of ω-3 PUFAs on ARG2 mRNA levels and provide further evidence for a role of ω-3 PUFAs in AR.

The Effects of Resveratrol on Prostate Cancer through Targeting the Tumor Microenvironment.

Prostate cancer is one of the most common cancers diagnosed in men in the United States and the second leading cause of cancer-related deaths worldwide. Since over 60% of prostate cancer cases occur in men over 65 years of age, and this population will increase steadily in the coming years, prostate cancer will be a major cancer-related burden in the foreseeable future. Accumulating data from more recent research suggest that the tumor microenvironment (TME) plays a previously unrecognized role in every stage of cancer development, including initiation, proliferation, and metastasis. Prostate cancer is not only diagnosed in the late stages of life, but also progresses relatively slowly. This makes prostate cancer an ideal model system for exploring the potential of natural products as cancer prevention and/or treatment reagents because they usually act relatively slowly compared to most synthetic drugs. Resveratrol (RSV) is a naturally occurring stilbenoid and possesses strong anti-cancer properties with few adverse effects. Accumulating data from both in vitro and in vivo experiments indicate that RSV can interfere with prostate cancer initiation and progression by targeting the TME. Therefore, this review is aimed to summarize the recent advancement in RSV-inhibited prostate cancer initiation, proliferation, and metastasis as well as the underlying molecular mechanisms, with particular emphasis on the effect of RSV on TME. This will not only better our understanding of prostate cancer TMEs, but also pave the way for the development of RSV as a potential reagent for prostate cancer prevention and/or therapy.

Repurposing dextromethorphan and metformin for treating nicotine-induced cancer by directly targeting CHRNA7 to inhibit JAK2/STAT3/SOX2 signaling.

Smoking is one of the most impactful lifestyle-related risk factors in many cancer types including esophageal squamous cell carcinoma (ESCC). As the major component of tobacco and e-cigarettes, nicotine is not only responsible for addiction to smoking but also a carcinogen. Here we report that nicotine enhances ESCC cancer malignancy and tumor-initiating capacity by interacting with cholinergic receptor nicotinic alpha 7 subunit (CHRNA7) and subsequently activating the JAK2/STAT3 signaling pathway. We found that aberrant CHRNA7 expression can serve as an independent prognostic factor for ESCC patients. In multiple ESCC mouse models, dextromethorphan and metformin synergistically repressed nicotine-enhanced cancer-initiating cells (CIC) properties and inhibited ESCC progression. Mechanistically, dextromethorphan non-competitively inhibited nicotine binding to CHRNA7 while metformin downregulated CHRNA7 expression by antagonizing nicotine-induced promoter DNA hypomethylation of CHRNA7. Since dextromethorphan and metformin are two safe FDA-approved drugs with minimal undesirable side-effects, the combination of these drugs has a high potential as either a preventive and/or a therapeutic strategy against nicotine-promoted ESCC and perhaps other nicotine-sensitive cancer types as well.

Case Report: Co-Existence of BRCA2 and PALB2 Germline Mutations in Familial Prostate Cancer With Solitary Lung Metastasis.

BACKGROUND: Mutation-caused loss-of-function of factors involved in DNA damage response (DDR) is responsible for the development and progression of ~20% of prostate cancer (PCa). Some mutations can be used in cancer risk assessment and informed treatment decisions. METHODS: Target capture-based deep sequencing of 11 genes was conducted with total DNA purified from the proband's peripheral blood. Sanger sequencing was conducted to screen potential germline mutations in the proband's family members. Targeted sequencing of a panel of 1,021 genes was done with DNA purified from the tumor tissue. RESULTS: Two previously unreported germline mutations in the DDR pathway, BRCA2 (c.8474_8487delCATACCCTATACAG, p.A2825Vfs*15) and PALB2 (c.472delC, p.Q158Rfs*19) were identified in a patient with metastatic PCa. A specific therapeutic regimen including androgen deprivation therapy, locally radical radiotherapy, and systemic platinum chemotherapy worked well against his cancer. In addition, the metastatic ovarian cancer in the proband's half-sister harboring the same BRCA2 germline mutation also responded well to platinum chemotherapy. CONCLUSIONS: The newly identified germline mutations in DDR plays important role in PCa development. Since specific regimen worked well against this cancer, screening of DDR mutation could provide better management for patients with these mutation-mediated PCa.

Emerging Therapeutic Strategies for COVID-19 patients.

Over 100,000 cases of COVID-19 patients infected with the novel coronavirus SARS-COV-2 have been reported worldwide in approximately 2 months, resulting in over 3000 deaths. Potential therapeutic strategies, including remdesivir, chloroquine phosphate, abidol, lopinavir/ritonavir, plasma, antibody, vaccine and stem cells are discussed in this review. With the number of patients increasing daily, there is an urgent need for effective therapeutic intervention.

Resveratrol enhances polyubiquitination-mediated ARV7 degradation in prostate cancer cells.

Although androgen deprivation therapy (ADT) serves as the primary treatment option for localized or metastatic prostate cancer, most cases eventually develop into castration-resistant prostate cancer (CRPC). However, androgen receptor (AR) continues to be functional in CRPC through various mechanisms, including the development of AR splicing variants, especially ARV7. Since it lacks the ligand binding domain but retains the intact DNA binding domain, ARV7 is constitutively active, which makes ARV7-positive prostate cancer responsive to neither abiraterone nor enzalutamide. In this study, we explored the effect of resveratrol on ARV7 transcriptional activity and the potential for development of resveratrol as a treatment for ARV7-positive prostate cancer. First, we ectopically expressed ARV7 in PC3 cells, an AR-negative prostate cancer cell line, and demonstrated that resveratrol is capable of inhibiting ARV7 transcriptional activity by downregulating ARV7 protein levels. Of note, resveratrol does not affect the mRNA levels of ARV7 nor its nuclear translocation. Next, we demonstrated that resveratrol is capable of downregulating the levels of the endogenously expressed ARV7 as well as AR target gene mRNAs in 22RV1 prostate cancer cells. Mechanistically, resveratrol downregulates ARV7 by enhancing ARV7 polyubiquitination and subsequent proteasome-mediated degradation. These findings suggest that resveratrol could be a potential treatment for ARV7-positive CPRC.

Metformin reverses prostate cancer resistance to enzalutamide by targeting TGF-ß1/STAT3 axis-regulated EMT.

Although the newly developed second-generation anti-androgen drug enzalutamide can repress prostate cancer progression significantly, it only extends the survival of prostate cancer patients by 4-6 months mainly due to the occurrence of enzalutamide resistance. Most of the previous studies on AR antagonist resistance have been focused on AR signaling. Therefore, the non-AR pathways on enzalutamide resistance remain largely unknown. By using C4-2, CWR22Rv1 and LNCaP cell lines, as well as mice bearing CWR22Rv1 xenografts treated with either enzalutamide or metformin alone or in combination, we demonstrated that metformin is capable of reversing enzalutamide resistance and restores sensitivity of CWR22Rv1 xenografts to enzalutamide. We showed that metformin alleviated resistance to enzalutamide by inhibiting EMT. Furthermore, based on the effect of metformin on the activation of STAT3 and expression of TGF-ß1, we propose that metformin exerts its effects by targeting the TGF-ß1/STAT3 axis. These findings suggest that combination of metformin with enzalutamide could be a more efficacious therapeutic strategy for the treatment of castration-resistant prostate cancer.

Small-molecule inhibitors of acetyltransferase p300 identified by high-throughput screening are potent anticancer agents.

Acetyltransferase p300 (KAT3B) plays key roles in signaling cascades that support cancer cell survival and sustained proliferation. Thus, p300 represents a potential anticancer therapeutic target. To discover novel anticancer agents that target p300, we conducted a high-throughput screening campaign. A library of 622,079 compounds was assayed for cytotoxicity to the triple-negative breast cancer (TNBC) cell line MDA-MB-231 but not to the human mammary epithelial cells. The resulting compounds were tested in a biochemical assay for inhibiting the enzymatic activity of p300. One compound (L002, NSC764414) displayed an IC50 of 1.98 µmol/L against p300 in vitro, inhibited acetylation of histones and p53, and suppressed STAT3 activation in cell-based assays. L002 could be docked to the active site of the p300 catalytic domain. Biochemical tests of a series of related compounds revealed functional groups that may impact inhibitory potency of L002 against p300. Interestingly, these analogs showed inhibitory activities against the cellular paralog of p300 (CBP), p300/CBP-associated factor, and GCN5, but not to other acetyltransferases (KAT5, KAT6B, and KAT7), histone deacetylases, and histone methyltransferases. Among the NCI-60 panel of cancer cell lines, leukemia and lymphoma cell lines were extremely sensitive to L002, whereas it is toxic to only a limited number of cell lines derived from solid tumors. Notably, breast cancer cell lines, especially those derived from TNBC, were highly susceptible to L002. In vivo, it potently suppressed tumor growth and histone acetylation of MDA-MB-468 xenografts. Thus, these new acetyltransferase inhibitors are potential anticancer therapeutics.

HIV-1 integration site preferences in pluripotent cells.

HIV-1-based vectors are widely used in gene therapy. In somatic cells, these vectors mainly integrate within genes. However, no distinct integration site preferences have been observed with regard to large chromosomal regions. The recent emergence of induced pluripotent stem (iPS) cells, similar to embryonic stem (ES) cells, has raised questions about where integration occurs in these cells. In this work we investigated the integration site preferences of HIV-1-based vectors in a pluripotent, ES-like cell line. We show that approximately 30% of the integrations occur in the vicinity of telomeres. We have analyzed integration sites in various somatic cells, as reported by us and other groups, and observed that this integration pattern is unique to the analyzed pluripotent cell line. We conclude that pluripotent cells may contain distinct cellular cofactors that participate in integration targeting and that are not present in somatic cells.

A role for the Werner syndrome protein in epigenetic inactivation of the pluripotency factor Oct4.

Werner syndrome (WS) is an autosomal recessive disorder, the hallmarks of which are premature aging and early onset of neoplastic diseases (Orren, 2006; Bohr, 2008). The gene, whose mutation underlies the WS phenotype, is called WRN. The protein encoded by the WRN gene, WRNp, has DNA helicase activity (Gray et al., 1997; Orren, 2006; Bohr, 2008; Opresko, 2008). Extensive evidence suggests that WRNp plays a role in DNA replication and DNA repair (Chen et al., 2003; Hickson, 2003; Orren, 2006; Turaga et al., 2007; Bohr, 2008). However, WRNp function is not yet fully understood. In this study, we show that WRNp is involved in de novo DNA methylation of the promoter of the Oct4 gene, which encodes a crucial stem cell transcription factor. We demonstrate that WRNp localizes to the Oct4 promoter during retinoic acid-induced differentiation of human pluripotent cells and associates with the de novo methyltransferase Dnmt3b in the chromatin of differentiating pluripotent cells. Depletion of WRNp does not affect demethylation of lysine 4 of the histone H3 at the Oct4 promoter, nor methylation of lysine 9 of H3, but it blocks the recruitment of Dnmt3b to the promoter and results in the reduced methylation of CpG sites within the Oct4 promoter. The lack of DNA methylation was associated with continued, albeit greatly reduced, Oct4 expression in WRN-deficient, retinoic acid-treated cells, which resulted in attenuated differentiation. The presented results reveal a novel function of WRNp and demonstrate that WRNp controls a key step in pluripotent stem cell differentiation.

Modification of integration site preferences of an HIV-1-based vector by expression of a novel synthetic protein.

HIV-1-based lentiviral vectors are a promising tool for gene therapy. However, integration of a lentiviral vector into host cell genes may lead to the development of cancer. Therefore, control of integration site selection is critical to the successful outcome of gene therapy approaches that use these vectors. The discovery that integration site selection by HIV-1 and HIV-1-based vectors is controlled by the LEDGF/p75 protein has presented new opportunities to control integration site selection. In this study, we tested the hypothesis that a fusion protein containing the C-terminal HIV integrase-binding portion of LEDGF/p75, and the N-terminal chromodomain of heterochromatin protein-1alpha (HP1alpha), can target HIV-1 vector DNA outside of genes. We show that this fusion protein, termed TIHPLE, associates with the heterochromatin hallmark trimethylated Lys-9 of histone H3 (H3K9me3). Transient overexpression of TIHPLE alters integration site selection by an HIV-1-based vector and decreases the number of integration events that occur in genes. This change in integration site selection was achieved without a reduction in overall integration efficiency. Furthermore, we show that TIHPLE increases integration in the vicinity of H3K9me3 and in repetitive DNA sequences. These data provide a novel approach to address the problem of the tendency of retroviral vectors to integrate at undesirable sites of the human genome.