Targeting LxCxE cleft pocket of retinoblastoma protein in M2 macrophages inhibits ovarian cancer progression.

Ovarian cancer remains a major health threat with limited treatment options available. It is characterized by immunosuppressive tumor microenvironment (TME) maintained by tumor- associated macrophages (TAMs) hindering anti-tumor responses and immunotherapy efficacy. Here we show that targeting retinoblastoma protein (Rb) by disruption of its LxCxE cleft pocket, causes cell death in TAMs by induction of ER stress, p53 and mitochondria-related cell death pathways. A reduction of pro-tumor Rb high M2-type macrophages from TME in vivo enhanced T cell infiltration and inhibited cancer progression. We demonstrate an increased Rb expression in TAMs in women with ovarian cancer is associated with poorer prognosis. Ex vivo, we show analogous cell death induction by therapeutic Rb targeting in TAMs in post-surgery ascites from ovarian cancer patients. Overall, our data elucidates therapeutic targeting of the Rb LxCxE cleft pocket as a novel promising approach for ovarian cancer treatment through depletion of TAMs and re-shaping TME immune landscape. Statement of significance: Currently, targeting immunosuppressive myeloid cells in ovarian cancer microenvironment is the first priority need to enable successful immunotherapy, but no effective solutions are clinically available. We show that targeting LxCxE cleft pocket of Retinoblastoma protein unexpectedly induces preferential cell death in M2 tumor-associated macrophages. Depletion of immunosuppressive M2 tumor-associated macrophages reshapes tumor microenvironment, enhances anti-tumor T cell responses, and inhibits ovarian cancer. Thus, we identify a novel paradoxical function of Retinoblastoma protein in regulating macrophage viability as well as a promising target to enhance immunotherapy efficacy in ovarian cancer.

The Natural Stilbenoid (-)-Hopeaphenol Inhibits HIV Transcription by Targeting Both PKC and NF-κB Signaling and Cyclin-Dependent Kinase 9.

Despite effective combination antiretroviral therapy (cART), people living with HIV (PLWH) continue to harbor replication-competent and transcriptionally active virus in infected cells, which in turn can lead to ongoing viral antigen production, chronic inflammation, and increased risk of age-related comorbidities. To identify new agents that may inhibit postintegration HIV beyond cART, we screened a library of 512 pure compounds derived from natural products and identified (-)-hopeaphenol as an inhibitor of HIV postintegration transcription at low to submicromolar concentrations without cytotoxicity. Using a combination of global RNA sequencing, plasmid-based reporter assays, and enzyme activity studies, we document that hopeaphenol inhibits protein kinase C (PKC)- and downstream NF-κB-dependent HIV transcription as well as a subset of PKC-dependent T-cell activation markers, including interleukin-2 (IL-2) cytokine and CD25 and HLA-DRB1 RNA production. In contrast, it does not substantially inhibit the early PKC-mediated T-cell activation marker CD69 production of IL-6 or NF-κB signaling induced by tumor necrosis factor alpha (TNF-α). We further show that hopeaphenol can inhibit cyclin-dependent kinase 9 (CDK9) enzymatic activity required for HIV transcription. Finally, it inhibits HIV replication in peripheral blood mononuclear cells (PBMCs) infected in vitro and dampens viral reactivation in CD4+ cells from PLWH. Our study identifies hopeaphenol as a novel inhibitor that targets a subset of PKC-mediated T-cell activation pathways in addition to CDK9 to block HIV expression. Hopeaphenol-based therapies could complement current antiretroviral therapy otherwise not targeting cell-associated HIV RNA and residual antigen production in PLWH.

BCL6 BTB-specific inhibitor reversely represses T-cell activation, Tfh cells differentiation, and germinal center reaction in vivo.

Inhibition of the BCL6 BTB domain results in killing Diffuse Large B-cell Lymphoma (DLBL) cells, reducing the T-cell dependent germinal center (GC) reaction in mice, and reversing GC hyperplasia in nonhuman primates. The available BCL6 BTB-specific inhibitors are poorly water soluble, thus, limiting their absorption in vivo and our understanding of therapeutic strategy targeting GC. We synthesized a prodrug (AP-4-287) from a potent BCL6 BTB inhibitor (FX1) with improved aqueous solubility and pharmacokinetics (PK) in mice. We also evaluated its in vivo biological activity on humoral immune responses using the sheep red blood cells (SRBC)-vaccination mouse model. AP-4-287 had a significant higher aqueous solubility and was readily converted to FX1 in vivo after intraperitoneally (i.p.) administration, but a shorter half-life in vivo. Importantly, AP-4-287 treatment led to a reversible effect on (1) the reduction in the frequency of splenic Ki67+ CD4+ T cells, Tfh cells, and GC B cells; (2) lower GC formation following vaccination; and (3) a decrease in the titers of antigen-specific IgG and IgM antibodies. Our study advances the preclinical development of drug targeting BCL6 BTB domain for the treatment of diseases that are associated with abnormal BCL6 elevation.

Stem cells of the lower limb: their role and potential in management of critical limb ischemia.

Peripheral arterial occlusive disease (PAOD) contributes to decreased exercise tolerance, poor balance, impaired proprioception, muscle atrophy and weakness, with advanced cases resulting in critical limb ischemia (CLI) where the viability of the limb is threatened. Patients with a diagnosis of CLI have a poor life expectancy due to concomitant cardio and cerebrovascular diseases. The current treatment options to avoid major amputation by re-establishing a blood supply to the limb generally have poor outcomes. Human skeletal muscle contains both multipotent stem cells and progenitor cells and thus has a capacity for regeneration. Phase I and II studies involving transplantation of bone marrow-derived progenitor cells into CLI limbs show positive effects on wound healing and angiogenesis; the increase in quiescent satellite cell numbers observed in CLI muscle may also provide a sufficient in vivo source of resident stem cells. These indigenous cells have been shown to be capable of forming multiple mesodermal cell lineages aiding the repair and regeneration of chronically ischemic muscle. They may also serve as a repository for autologous transplantation. The behavior and responses of the stem cell population in CLI is poorly understood and this review tries to elucidate the potential of these cells and their future role in the management of CLI.

The emerging harm of antioxidants in carcinogenesis.

Early epidemiologic studies have hinted at an anticancer role for multiple antioxidant compounds that are present in fresh produce. These substances target reactive oxygen and nitrogen species and potentially reduce oxidative damage to DNA that results in mutagenic change and potentially the initiation of cancer, disease and aging. It is tempting to believe that these compounds, through their in vitro actions as observed in cancer cell lines and certain animal experiments, may have the same anticarcinogenic role in humans. This article summarizes the relationship between fresh produce and antioxidant supplements and cancer risks from recent epidemiologic studies as well as identifying worrying trends and future directions for research into this most controversial field. Recent molecular data suggest that certain antioxidants may contribute towards oncogenesis.

T-tube duodenocholangiostomy for the management of duodenal fistulae.

BACKGROUND: The tube decompression of the duodenum through an additional point of access of the duodenal wall or occasionally via the leak site decreases morbidity and mortality in patients with duodenal fistula. The objective of this paper is to present the detailed technique and clinical benefits of simplified duodenal and biliary decompression achieved by transampullary insertion of a T-tube with one-step duodenal closure for the prevention and/or treatment of duodenal leak. METHODS: The duodenocholangiostomy using T-tube with laterally perforated long duodenal limb was performed preventively in 4 patients and as a secondary procedure for septic duodenal leak in another selected 12. The mean output from the fistula, length of hospital stay, incidence of pancreatitis, as well as any postoperative septic events was recorded. The nutritional schedule during the in early postoperative period also was analyzed. RESULTS: The outcome was favorable for all patients. The mean length of hospital stay was 19 days. Septic events, such as wound or urinary tract infections, were observed in 30% of patients. Serum amylase and lipase activity was increased in two patients without a clinical picture of pancreatitis. Mean volume of T-tube duodenocholangiostomy drainage was approximately 500 ml per day during the first postoperative week. Enteral feeding was commenced 10-52 (mean, 21) hours after surgery and was followed by the initiation of normal diet on average 5 days postoperatively. CONCLUSIONS: Duodenocholangiostomy performed for duodenal decompression may be a promising alternative to classical tube duodenostomy for selected patients; however, further studies should be made to evaluate fully its practical value.

Pancreas sparing duodenectomy as an emergency procedure.

BACKGROUND: The operative techniques to close extensive wounds to the duodenum are well described. However, postoperative morbidity is common and includes suture line leak and the formation of fistulae. The aim of this case series is to present pancreas sparing duodenectomy as a safe and viable alternative procedure in the emergency milieu. METHODS: Five patients underwent emergency pancreas sparing duodenal excisions. Re-implantation of the papilla of Vater or the papilla with a surrounding mucosal patch was performed in two patients. In one, the procedure was further supplemented with a duodenocholangiostomy, stapled pyloric exclusion and enterogastrostomy to defunction the pylorus. In another three patients, distal duodenal excisions were done. RESULTS: In four patients, an uneventful recovery was made. One patient died following a myocardial infarction. The surgery lasted meanly 160 minutes with average blood loss of approximately 500 milliliters. The mean hospital stay was 12 days. Enteral nutrition was introduced within the 20 hours after the surgery. Long term follow-up of all surviving patients confirmed a good outcome and normal nutritional status. CONCLUSION: Based on the presented series of patients, we suggest that pancreas-sparing duodenectomy can be considered in selected patients with laceration of the duodenum deemed unsuitable for surgical reconstruction.