BackgroundMicroRNAs (miRNAs) have been implicated in cancer initiation and progression via their ability to affect expression of genes and proteins that regulate cell proliferation and/or cell death. Transcription of the three miRNA miR-34 family members was recently found to be directly regulated by p53. Among the target proteins regulated by miR-34 are Notch pathway proteins and Bcl-2, suggesting the possibility of a role for miR-34 in the maintenance and survival of cancer stem cells.Methodology/Principal FindingsWe examined the roles of miR-34 in p53-mutant human pancreatic cancer cell lines MiaPaCa2 and BxPC3, and the potential link to pancreatic cancer stem cells. Restoration of miR-34 expression in the pancreatic cancer cells by either transfection of miR-34 mimics or infection with lentiviral miR-34-MIF downregulated Bcl-2 and Notch1/2. miR-34 restoration significantly inhibited clonogenic cell growth and invasion, induced apoptosis and G1 and G2/M arrest in cell cycle, and sensitized the cells to chemotherapy and radiation. We identified that CD44+/CD133+ MiaPaCa2 cells are enriched with tumorsphere-forming and tumor-initiating cells or cancer stem/progenitor cells with high levels of Notch/Bcl-2 and loss of miR-34. More significantly, miR-34 restoration led to an 87% reduction of the tumor-initiating cell population, accompanied by significant inhibition of tumorsphere growth in vitro and tumor formation in vivo.Conclusions/SignificanceOur results demonstrate that miR-34 may restore, at least in part, the tumor suppressing function of the p53 in p53-deficient human pancreatic cancer cells. Our data support the view that miR-34 may be involved in pancreatic cancer stem cell self-renewal, potentially via the direct modulation of downstream targets Bcl-2 and Notch, implying that miR-34 may play an important role in pancreatic cancer stem cell self-renewal and/or cell fate determination. Restoration of miR-34 may hold significant promise as a novel molecular therapy for human pancreatic cancer with loss of p53–miR34, potentially via inhibiting pancreatic cancer stem cells.

Background ST-segment elevation myocardial infarction (STEMI) is a fatal cardiovascular emergency requiring rapid reperfusion treatment. During the coronavirus disease-2019 (COVID-19) pandemic, medical professionals need to strike a balance between providing timely treatment for STEMI patients and implementing infection control procedures to prevent nosocomial spread of COVID-19 among health care workers and other vulnerable cardiovascular patients. Objectives This study evaluates the impact of the COVID-19 outbreak and China Chest Pain Center’s modified STEMI protocol on the treatment and prognosis of STEMI patients in China. Methods Based on the data of 28,189 STEMI patients admitted to 1,372 Chest Pain Centers in China between December 27, 2019 and February 20, 2020, the study analyzed how the COVID-19 outbreak and China Chest Pain Center’s modified STEMI protocol influenced the number of admitted STEMI cases, reperfusion strategy, key treatment time points, and in-hospital mortality and heart failure for STEMI patients. Results The COVID-19 outbreak reduced the number of STEMI cases reported to China Chest Pain Centers. Consistent with China Chest Pain Center’s modified STEMI protocol, the percentage of patients undergoing primary percutaneous coronary intervention declined while the percentage of patients undergoing thrombolysis increased. With an average delay of approximately 20 min for reperfusion therapy, the rate of in-hospital mortality and in-hospital heart failure increased during the outbreak, but the rate of in-hospital hemorrhage remained stable. Conclusions There were reductions in STEMI patients’ access to care, delays in treatment timelines, changes in reperfusion strategies, and an increase of in-hospital mortality and heart failure during the COVID-19 pandemic in China.

A natural BH3-mimetic, small molecule inhibitor of Bcl-2, (-)-gossypol, shows promise in ongoing Phase II-III clinical trials for human prostate cancer. Here we show that (-)-gossypol preferentially induces autophagy in androgen-independent (AI) prostate cancer cells that have high levels of Bcl-2 and are resistant to apoptosis, both in vitro and in vivo, but not in androgen-dependent cells with low Bcl-2 and sensitive to apoptosis. The Bcl-2 inhibitor induces autophagy via blocking Bcl-2—Beclin1 interaction, together with downregulating Bcl-2, upregulating Beclin1 and activating the autophagic pathway. (-)-Gossypol-induced autophagy is Beclin1- and Atg5-dependent. Our results demonstrate for the first time that (-)-gossypol can also interrupt the interactions between Beclin1 and Bcl-2/Bcl-xL at endoplasmic reticulum, thus releasing the BH3-only pro-autophagic protein Beclin1, which in turn triggers the autophagic cascade. Oral administration of (-)-gossypol significantly inhibited the growth of AI prostate cancer xenografts, representing a promising new regimen for the treatment of human hormone-refractory prostate cancer with Bcl-2 overexpression. Our data provide new insights into the mode of cell death induced by Bcl-2 inhibitors, which would facilitate the rational design of clinical trials by selecting patients who are most likely to benefit from the Bcl-2-targeted molecular therapy.

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A pharmacogenetics-based dosing algorithm has been developed for improvement in the time to reach the stable dosing of warfarin. This model may be useful in helping the clinicians to prescribe warfarin with greater safety and efficiency.

Background: Short-term exposure to ambient air pollution has been linked with daily hospitalization and mortality of acute coronary syndrome (ACS); however, the associations of sub-daily (hourly) levels of criteria air pollutants with the onset of ACS and its subtypes have rarely been evaluated. Methods: We conducted a time-stratified case-crossover study among 1,292,880 ACS patients from 2,239 hospitals in 318 Chinese cities between January 1, 2015, and September 30, 2020. Hourly concentrations of fine particulate matter (PM 2.5 ), coarse particulate matter (PM 2.5-10 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), and ozone (O 3 ) were collected. Hourly onset data of ACS and its subtypes, including ST-segment-elevation myocardial infarction, non-ST-segment-elevation myocardial infarction, and unstable angina, were also obtained. Conditional logistic regressions combined with polynomial distributed lag models were applied. Results: Acute exposures to PM 2.5 , NO 2 , SO 2 , and CO were each associated with the onset of ACS and its subtype. These associations were strongest in the concurrent hour of exposure and were attenuated thereafter, with the weakest effects observed after 15-29 hours. There were no apparent thresholds in the concentration-response curves. An interquartile range increase in concentrations of PM 2.5 (36.0 μg/m 3 ), NO 2 (29.0 μg/m 3 ), SO 2 (9.0 μg/m 3 ), and CO (0.6 mg/m 3 ) over the 0-24 hours preceding onset was significantly associated with 1.32%, 3.89%, 0.67%, and 1.55% higher risks of ACS onset, respectively. For a given pollutant, the associations were comparable in magnitude across different subtypes of ACS. Generally, NO 2 showed the strongest associations with all three subtypes, followed by PM 2.5 , CO, and SO 2 . Greater magnitude of associations was observed among patients older than 65, without a history of smoking or chronic cardiorespiratory diseases, and in the cold season. Null associations of exposure to either PM 2.5-10 or O 3 with ACS onset were observed. Conclusions: The results suggest that transient exposure to the air pollutants of PM 2.5 , NO 2 , SO 2 , CO, but not PM 2.5-10 or O 3 , may trigger the onset of ACS, even at concentrations below the World Health Organization air-quality guidelines.

Dually targeted mitochondrial proteins usually possess an unconventional mitochondrial targeting sequence (MTS), which makes them difficult to predict by current bioinformatics approaches. Human apurinic/apyrimidinic endonuclease (APE1) plays a central role in the cellular response to oxidative stress. It is a dually targeted protein preferentially residing in the nucleus with conditional distribution in the mitochondria. However, the mitochondrial translocation mechanism of APE1 is not well characterized because it harbors an unconventional MTS that is difficult to predict by bioinformatics analysis. Two experimental approaches were combined in this study to identify the MTS of APE1. First, the interactions between the peptides from APE1 and the three purified translocase receptors of the outer mitochondrial membrane (Tom) were evaluated using a peptide array screen. Consequently, the intracellular distribution of green fluorescent protein-tagged, truncated, or mutated APE1 proteins was traced by tag detection. The results demonstrated that the only MTS of APE1 is harbored within residues 289 -318 in the C terminus, which is normally masked by the intact N-terminal structure. As a dually targeted mitochondrial protein, APE1 possesses a special distribution pattern of different subcellular targeting signals, the identification of which sheds light on future prediction of MTSs.Human APE1 (apurinic/apyrimidinic endonuclease) is an important multifunctional protein that plays a central role in the cellular response to oxidative stress. The two major activities of APE1 are DNA repair and redox regulation of transcriptional factors. On one hand, APE1 functions as a critical ratelimiting enzyme in DNA base excision repair and accounts for nearly all of the AP site incision activities in cell extracts (1). On the other hand, APE1 also exerts unique redox activity to regulate the DNA binding affinity of certain transcriptional factors by controlling the redox status of their DNA-binding domain (2). Inhibition of the redox function of APE1 blocks murine endothelial cell growth and angiogenesis and also blocks the growth of human tumor cell lines (3). The biological importance of APE1 is highlighted by the finding that APE1 knockout mice exhibit an embryonic lethal phenotype (4). Although APE1 has long been labeled as a nuclear protein, a growing body of evidence has shown that the subcellular distribution of APE1 can be cytoplasmic in some cell types with high metabolic or proliferative rates, with predominant localization in the mitochondria and the endoplasmic reticulum (5-7). Recent mitochondrial proteomic studies have further confirmed the existence of APE1 in the mitochondria (8). Considering the importance of the mitochondria in cellular response to oxidative stress, the roles of APE1 in the mitochondria have been extensively investigated.

Caffeic acid phenethyl ester, an active component of propolis, has been implicated in the regulation of cell growth and apoptosis, although the exact mechanism of this activity has not been elucidated. In this study, we explored the effects of caffeic acid phenethyl ester on growth, cell cycle, apoptosis and beta-catenin/T-cell factor signaling in human colon cancer cells. Using two human sporadic colon cancer cell lines (HCT116 and SW480), we assayed for cell growth inhibition, cell cycle and apoptosis induction. We also assayed for beta-catenin and downstream target genes (cyclin D1 and c-myc) mRNA and protein expression by reverse transcriptase-polymerase chain reaction and Western blot analysis. Beta-catenin localization was detected by indirect immunofluorescence. Beta-catenin/T-cell factor transcriptional activity was determined by transient transfection and reporter gene assay. Caffeic acid phenethyl ester completely inhibited growth, and induced G1 phase arrest and apoptosis in a dose-dependent manner in both HCT116 and SW480 cells. Treatment of human colon cancer cells with apoptotic concentrations of caffeic acid phenethyl ester resulted in a dose-dependent and time-dependent loss of total beta-Catenin protein, associated with decreased nuclear beta-catenin. Caffeic acid phenethyl ester reduced the expression of cyclin D1 and c-myc in a dose-dependent and time-dependent manner. We proved that caffeic acid phenethyl ester markedly suppressed the transcriptional activity of beta-catenin/T-cell factor in both HCT116 and SW480 cells depending on the concentration of caffeic acid phenethyl ester. These results indicate that caffeic acid phenethyl ester is an excellent inhibitor of beta-catenin/T-cell factor signaling in colon cancer cell lines and suggest that caffeic acid phenethyl ester merits further study as an agent against colorectal cancers.