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PurposeButyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated autophagy, and whether there was crosstalk between autophagy and the sodium butyrate-induced apoptotic response in human colorectal cancer cells.MethodsHuman colorectal cancer cell lines (HCT-116 and HT-29) were treated with sodium butyrate at concentrations ranging from 0.5–5mM. Cell proliferation was assessed using MTT tetrazolium salt formation. Autophagy induction was confirmed through a combination of Western blotting for associated proteins, acridine orange staining for acidic vesicles, detection of autolysosomes (MDC staining), and electron microscopy. Apoptosis was quantified by flow cytometry using standard annexinV/propidium iodide staining and by assessing PARP-1 cleavage by Western blot.ResultsSodium butyrate suppressed colorectal cancer cell proliferation, induced autophagy, and resulted in apoptotic cell death. The induction of autophagy was supported by the accumulation of acidic vesicular organelles and autolysosomes, and the expression of autophagy-associated proteins, including microtubule-associated protein II light chain 3 (LC3-II), beclin-1, and autophagocytosis-associated protein (Atg)3. The autophagy inhibitors 3-methyladenine (3-MA) and chloroquine inhibited sodium butyrate induced autophagy. Furthermore, sodium butyrate treatment markedly enhanced the expression of endoplasmic reticulum stress-associated proteins, including BIP, CHOP, PDI, and IRE-1a. When endoplasmic reticulum stress was inhibited by pharmacological (cycloheximide and mithramycin) and genetic (siRNA targeting BIP and CHOP) methods, the induction of BIP, PDI, IRE1a, and LC3-II was blocked, but PARP cleavage was markedly enhanced.DiscussionTaken together, these results suggested that sodium butyrate-induced autophagy was mediated by endoplasmic reticulum stress, and that preventing autophagy by blocking the endoplasmic reticulum stress response enhanced sodium butyrate-induced apoptosis. These results provide novel insights into the anti-tumor mechanisms of butyric acid.

BACKGROUND Optimal blood pressure (BP) levels during acute ischemic stroke have not been established. We studied associations between systolic BP trajectories during acute phase and subsequent clinical outcomes among patients with ischemic stroke. METHODS A total of 4,036 patients with acute ischemic stroke and elevated BP from the China Antihypertensive Trial in Acute Ischemic Stroke trial were included in this analysis. Three BPs were measured every 2 hours in day 1, every 4 hours during days 2 and 3, and every 8 hours thereafter until hospital discharge or death. Clinical outcomes were assessed at 3, 12, and 24 months. Latent variable mixture modeling was used to identify subgroups that share a similar underlying trajectory of systolic BP during the first 7 days after stroke onset. Logistic regression and Cox proportional hazards models were used to examine the associations between systolic BP trajectories and clinical outcomes during follow-up. RESULTS We identified 5 systolic BP trajectories of high, high-to-moderate-low, moderate-high, moderate-low, and low. Compared to participants in high trajectory, multiple-adjusted odds ratios (95% confidence interval) of all-cause mortality at 3 months for individuals in high-to-moderate-low, moderate-high, moderate-low, and low were 0.34 (0.15–0.77), 0.58 (0.32–1.04), 0.29 (0.15–0.56), and 0.56 (0.26–1.19), respectively. Likewise, the corresponding hazard ratios for all-cause mortality in 24 months were 0.66 (0.44–1.00), 0.74 (0.53–1.05), 0.45 (0.32–0.66), and 0.61 (0.40–0.93), respectively. Similar associations were observed for recurrent stroke and cardiovascular disease, and in both the intervention and control groups. CONCLUSIONS Patients with moderate-low systolic BP during acute ischemic stroke had a lower risk of adverse clinical outcomes.

This study was undertaken to test two therapies for acute kidney injury (AKI) prevention, IGF-1, which is renal protective, and BTP-2, which is a calcium entry (SOCE) inhibitor. We utilized lipopolysaccharide (LPS) IP, as a systemic model of AKI and studied in five groups of animals. Three experiments showed that at 7 days: (1) LPS significantly reduced serum IGF-1 and intramuscular IGF-I in vivo gene therapy rescued this deficiency. (2) Next, at the 7-day time point, our combination therapy, compared to the untreated group, caused a significant increase in survival, which was noteworthy because all of the untreated animals died in 72 h. (3) The four pathways associated with inflammation, including (A) increase in cytosolic calcium, (B) elaboration of proinflammatory cytokines, (C) impairment of vascular integrity, and (D) cell injury, were adversely affected in renal tissue by LPS, using a sublethal dose of LPS. The expression of several genes was measured in each of the above pathways. The combined therapy of IGF-1 and BTP-2 caused a favorable gene expression response in all four pathways. Our current study was an AKI study, but these pathways are also involved in other types of severe inflammation, including sepsis, acute respiratory distress syndrome, and probably severe coronavirus infection.