Jerantinine A induces tumor-specific cell death through modulation of splicing factor 3b subunit 1 (SF3B1)

Precursor mRNA (pre-mRNA) splicing is catalyzed by a large ribonucleoprotein complex known as the spliceosome. Numerous studies have indicated that aberrant splicing patterns or mutations in spliceosome components, including the splicing factor 3b subunit 1 (SF3B1), are associated with hallmark cancer phenotypes. This has led to the identification and development of small molecules with spliceosome-modulating activity as potential anticancer agents. Jerantinine A (JA) is a novel indole alkaloid which displays potent anti-proliferative activities against human cancer cell lines by inhibiting tubulin polymerization and inducing G2/M cell cycle arrest. Using a combined pooled-genome wide shRNA library screen and global proteomic profiling, we showed that JA targets the spliceosome by up-regulating SF3B1 and SF3B3 protein in breast cancer cells. Notably, JA induced significant tumor-specific cell death and a significant increase in unspliced pre-mRNAs. In contrast, depletion of endogenous SF3B1 abrogated the apoptotic effects, but not the G2/M cell cycle arrest induced by JA. Further analyses showed that JA stabilizes endogenous SF3B1 protein in breast cancer cells and induced dissociation of the protein from the nucleosome complex. Together, these results demonstrate that JA exerts its antitumor activity by targeting SF3B1 and SF3B3 in addition to its reported targeting of tubulin polymerization

Cudraflavone C induces tumor-specific apoptosis in colorectal cancer cells through inhibition of the phosphoinositide 3-kinase (PI3K)-AKT pathway

Cudraflavone C (Cud C) is a naturally-occurring flavonol with reported anti-proliferative activities. However, the mechanisms by which Cud C induced cytotoxicity have yet to be fully elucidated. Here, we investigated the effects of Cud C on cell proliferation, caspase activation andapoptosis induction in colorectal cancer cells (CRC). We show that Cud C inhibits cell proliferation in KM12, Caco-2, HT29, HCC2998, HCT116 and SW48 CRC but not in the non-transformed colorectal epithelial cells, CCD CoN 841. Cud C induces tumorselective apoptosis via mitochondrial depolarization and activation of the intrinsic caspase pathway. Gene expression profiling by microarray analyses revealed that tumor suppressor genes EGR1, HUWE1 and SMG1 were significantly up-regulated while oncogenes such as MYB1, CCNB1 and GPX2 were down-regulated following treatment with Cud C. Further analyses using Connectivity Map revealed that Cud C induced a gene signature highly similar to that of protein synthesis inhibitors and phosphoinositide 3-kinase (PI3K)-AKT inhibitors, suggesting that Cud C might inhibit PI3K-AKT signaling. A luminescent cell free PI3K lipid kinase assay revealed that Cud C significantly inhibited p110?/p85? PI3K activity, followed by p120?, p110?/p85?, and p110?/p85? PI3K activities. The inhibition by Cud C on p110?/p85? PI3K activity was comparable to LY-294002, a known PI3K inhibitor. Cud C also inhibited phosphorylation of AKT independent of NF?B activity in CRC cells, while ectopic expression of myristoylated AKT completely abrogated the anti-proliferative effects, and apoptosis induced by Cud C in CRC. These findings demonstrate that Cud C induces tumor-selective cytotoxicity by targeting the PI3K-AKT pathway. These findings provide novel insights into the mechanism of action of Cud C, and indicate that Cud C further development of Cud C derivatives as potential therapeutic agents is warranted

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Fibroblast growth factor receptor 4 (FGF4) and fibroblast growth factor 19 (FGFR19) autocrine enhance brest cancer cells survival

Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4+/FGF19+ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers

Cudraflavone C inhibits PI3K activity.

<p>The effect of negative control (1%DMSO), Cud C or LY-294002 (100 μM) on p110α/p85α, p110β/p85α, p110δ/p85α, and p120γ PI3K activity were quantified using the PI3K-Glo^™ Class I Profiling Kit. All data represents the mean ± s.d. from at least three independent experiments. Symbol “*” presents the statistical significance concluded from Student’s independent <i>t</i>-test with p-value ≤0.05.</p

Cudraflavone C induces tumor-specific cell death in colorectal cancer cells.

<p>(A) Chemical structure of Cud C. (B) KM12, HT29, Caco-2, HCC2998, HCT116 and SW48 colorectal cancer cells were exposed to various concentrations of Cud C for 72 hours. Cell viability was recorded using CellTitre Glo^® luminescence assay. (C) KM12, Caco-2 and CCD 841 CoN were treated with 0.1% DMSO (control) or 10μM Cud C (Cud C) for 72 hours followed by microscopy analysis (×100 magnification). (D) Apoptotic cell death in KM12, Caco-2 and CCD 841 CoN cells was quantified using Annexin V/7-AAD flow cytometry at 72 hours following treatment. (E) Caspase activities in KM12 and Caco-2 cells were assessed by Caspase Glo^® assay at 72 hours following treatment. (F) 10μM Cud C induced mitochondrial membrane depolarization. Caco-2 and KM12 cells stained with JC-1 at 72 hours after treatment with Cud C. The green dye represents JC-1 monomers in cytoplasm while the red dye represents JC-1 aggregates in nucleus. Cells were observed under fluorescence microscope (×100 magnification). All data represent the mean ± s.d. from at least three independent experiments. Symbol “*” presents the statistical significance concluded from Student’s independent <i>t</i>-test with p-value ≤0.05.</p

IC₅₀ of Cud C and 5-fluorouracil in colorectal cancer and non-transformed colon epithelial cells.

<p>IC₅₀ of Cud C and 5-fluorouracil in colorectal cancer and non-transformed colon epithelial cells.</p

Differential gene expression regulated by cudraflavone C in Caco-2 cells.

<p>(A) Heatmaps generated based on the genes regulated by Cud C. Caco-2 cells were exposed to 10 μM Cud C for 48 hours. GeneChip^® Human Transcriptome Array 2.0 (Affymetrix, USA) was applied. Gene expression changes that ≥2-fold were considered significant. Control 1 and Control 2 represent gene expression from cells treated with vehicle control (1% DMSO); Cud C 1 and Cud C 2 were gene expression from cells treated with Cud C (10 μM). (B) qPCR was used to validate the microarray data. Caco-2 cells were exposed to 10 μM Cud C for 12, 24, 48 or 72 hours The left and right panels present genes that are up and down-regulated respectively. All data represent the mean ± s.d. from at least three independent experiments. Symbol “*” indicates the statistical significance concluded from Student’s independent <i>t</i>-test with p-value ≤0.05.</p

Top 20 pharmaceutical perturbagens exhibiting positive correlation to the gene signature induced by Cud C treatment.

<p>Top 20 pharmaceutical perturbagens exhibiting positive correlation to the gene signature induced by Cud C treatment.</p