Inhibition of MCF-7 breast cancer cell proliferation by a synthetic peptide derived from the C-terminal sequence of Orai channel.

Intracellular Ca2+ signals play many important cellular functions such as migration, proliferation and differentiation. Store-operated Ca2+ entry (SOCE) is a major route of Ca2+ entry in nonexcitable cells. The activation of SOCE requires engagement between stromal interaction molecule 1 (STIM1) molecules on the endoplasmic reticulum and Ca2+ release-activated Ca2+ (CRAC) channel Orais (Orai1-3) on the plasma membrane. Accumulating evidence indicates that SOCE plays critical roles in cancer cell proliferation, invasion and metastasis. Here, we used the synthetic intracellular peptides derived from the C-termini of Orai channels to treat the breast cancer cells. We have found that Orai3-CT peptide exhibits stronger binding to STIM1 than Orai1-CT, and Orai3-CT peptide acts in a dominant negative fashion, blocking the STIM1-Orai1 interaction and reducing the Ca2+ entry and proliferation of breast cancer cells.

Hypoxia-induced cysteine metabolism reprogramming is crucial for the tumorigenesis of colorectal cancer.

Metabolic reprogramming is a hallmark of human cancer, and cancer-specific metabolism provides opportunities for cancer diagnosis, prognosis, and treatment. However, the underlying mechanisms by which metabolic pathways affect the initiation and progression of colorectal cancer (CRC) remain largely unknown. Here, we demonstrate that cysteine is highly enriched in colorectal tumors compared to adjacent non-tumor tissues, thereby promoting tumorigenesis of CRC. Synchronously importing both cysteine and cystine in colorectal cancer cells is necessary to maintain intracellular cysteine levels. Hypoxia-induced reactive oxygen species (ROS) and ER stress regulate the co-upregulation of genes encoding cystine transporters (SLC7A11, SLC3A2) and genes encoding cysteine transporters (SLC1A4, SLC1A5) through the transcription factor ATF4. Furthermore, the metabolic flux from cysteine to reduced glutathione (GSH), which is critical to support CRC growth, is increased due to overexpression of glutathione synthetase GSS in CRC. Depletion of cystine/cysteine by recombinant cyst(e)inase effectively inhibits the growth of colorectal tumors by inducing autophagy in colorectal cancer cells through mTOR-ULK signaling axis. This study demonstrates the underlying mechanisms of cysteine metabolism in tumorigenesis of CRC, and evaluates the potential of cysteine metabolism as a biomarker or a therapeutic target for CRC.

Reprogramming the myocardial infarction microenvironment with melanin-based composite nanomedicines in mice.

Myocardial infarction (MI) has a 5-year mortality rate of more than 50% due to the lack of effective treatments. Interactions between cardiomyocytes and the MI microenvironment (MIM) can determine the progression and fate of infarcted myocardial tissue. Here, a specially designed Melanin-based composite nanomedicines (MCN) is developed to effectively treat MI by reprogramming the MIM. MCN is a nanocomposite composed of polydopamine (P), Prussian blue (PB) and cerium oxide (CexOy) with a Mayuan-like structure, which reprogramming the MIM by the efficient conversion of detrimental substances (H+, reactive oxygen species, and hypoxia) into beneficial status (O2 and H2O). In coronary artery ligation and ischemia reperfusion models of male mice, intravenously injecting MCN specifically targets the damaged area, resulting in restoration of cardiac function. With its promising therapeutic effects, MCN constitutes a new agent for MI treatment and demonstrates potential for clinical application.

FAK-mediated phosphorylation at Y464 regulates p85ß nuclear translocation to promote tumorigenesis of ccRCC by repressing RB1 expression.

PI3K regulatory subunit p85s normally stabilizes and regulates catalytic subunit p110s in the cytoplasm. Recent studies show that p110-free p85s in the nucleus plays important roles in biological processes. However, the mechanisms by which p85s translocate into the nucleus remain elusive. Here, we describe the mechanism by which p85ß translocates into the nucleus to promote ccRCC tumorigenesis. Phosphorylation of p85ß at the Y464 by FAK facilitates its nuclear translocation in the kidney through enhancing the binding of p85ß to KPNA1. PIK3R2/p85ß is highly expressed in ccRCC samples and associated with overall survival of ccRCC patients. Nuclear but not cytoplasmic p85ß performs oncogenic functions by repressing RB1 expression and regulating the G1/S cell cycle transition. Nuclear p85ß represses RB1 expression by stabilizing histone methyltransferase EZH1/EZH2 proteins. Last, the FAK inhibitor defactinib significantly suppresses the tumor growth of ccRCC with high p85ß Y464 levels.

The TRPM7 channel reprograms cellular glycolysis to drive tumorigenesis and angiogenesis.

Cancer or endothelial cells preferably catabolize glucose through aerobic glycolysis rather than oxidative phosphorylation. Intracellular ionic signaling has been shown to regulate glucose metabolism, but the underlying ion channel has yet to be identified. RNA-seq, metabolomics and genetic assay revealed that the TRPM7 channel regulated cellular glycolysis. Deletion of TRPM7 suppressed cancer cell glycolysis and reduced the xenograft tumor burden. Deficiency of endothelial TRPM7 inhibited postnatal retinal angiogenesis in mice. Mechanistically, TRPM7 transcriptionally regulated the solute carrier family 2 member 3 (SLC2A3, also known as GLUT3) via Ca2+ influx-induced calcineurin activation. Furthermore, CREB-regulated transcription coactivator 2 (CRTC2) and CREB act downstream of calcineurin to relay Ca2+ signal to SLC2A3 transcription. Expression of the constitutively active CRTC2 or CREB in TRPM7 knockout cell normalized glycolytic metabolism and cell growth. The TRPM7 channel represents a novel regulator of glycolytic reprogramming. Inhibition of the TRPM7-dependent glycolysis could be harnessed for cancer therapy.