Pentachloronitrobenzene disturbed murine ventricular wall development by inhibiting cardiomyocyte proliferation via Hec1 downregulation.

Exposure to the organochlorine fungicide pentachloronitrobenzene (PCNB) causes developmental abnormalities, including cardiac malformation. However, the molecular mechanism of PCNB cardiotoxicity remains elusive. We found that oral administration of PCNB to pregnant mice induced a hypoplastic wall with significant thinning of the compact myocardium in the developing hearts. PCNB significantly downregulates the expression of Hec1, a member of the NDC80 kinetochore complex, resulting in aberrant spindles, chromosome missegregation and an arrest in cardiomyocyte proliferation. Cardiac-specific ablation of Hec1 sharply inhibits cardiomyocyte proliferation, leading to thinning of the compact myocardium and embryonic lethality. Mechanistically, we found that activating transcription factor 3 (ATF3) transactivates Hec1 expression. Either HEC1 or ATF3 overexpression significantly rescues mitotic defects and restore the decreased proliferative ability of cardiomyocytes caused by PCNB exposure. Our findings highlight that maternal PCNB exposure disrupts embryonic cardiac function by inhibiting cardiomyocyte proliferation and interfering with ventricular wall development, partially attributed to the downregulation of the Atf3-Hec1 axis.

Antrodia camphorata extract (ACE)-induced apoptosis is associated with BMP4 expression and p53-dependent ROS generation in human colon cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Antrodia camphorata (AC) is a rare functional fungus in Taiwan and is known as traditional Chinese medicine. It has been reported to inhibit proliferation and promote apoptosis in human cancer cells. AIM OF THE STUDY: To investigate the potential mechanism of apoptosis induced in colon cancer cells by Antrodia camphorata extract (ACE). MATERIALS AND METHODS: The MTT assay and crystal violet staining were used to determine relative cell viability in vitro at 24 and 48 h. The effects of ACE on apoptosis were determined by Hoechst 33342 staining and flow cytometric analysis following Annexin V-FITC/PI staining. The gene expression profile of HCT116 cells was assessed by the RNA sequencing system. In combination with RNA-seq data and qRT-PCR, Western blot analysis was used to evaluate expression of proteins. The intracellular ROS of HCT116 cells were determined using a DCFH-DA fluorescence probe. RESULTS: ACE significantly reduces cell viability in a dose-dependent manner and triggers apoptosis. To explore the underlying mechanism, we performed transcriptome analysis of ACE-treated colon cancer HCT116 cells. Bioinformatics analyses showed that ACE treatment is associated with pathways in cancer. We further used Cytoscape to analyze hub genes in this network. Among them, BMP4, which is associated with cancer cell death through regulation of the tumor suppressor p53, was significantly decreased at both mRNA and protein levels in ACE treatment groups. We found that cell death is reversible via inactivation or knockdown of p53 gene and reduction of reactive oxygen species (ROS) generation in response to ACE exposure, indicating that p53 plays an important role in ROS generation induced by ACE. Meanwhile, ROS scavenger NAC was used to verify that cell death is reversible via reduction of ROS. CONCLUSION: Our findings demonstrate that ACE has potential as an anticancer agent that induces apoptosis through BMP4 and p53-dependent response to ROS in human colon cancer.

The implication of p66shc in oxidative stress induced by deltamethrin.

Deltamethrin (DLT) is effective against a broad spectrum of insects. Exposure to DLT has been demonstrated to cause oxidative stress. However, the mechanism of oxidative stress induced by DLT is little known. Groups of rats were gavaged with DLT once daily for 7 days at six dosages: 0, 2, 5, 10, 20, 40 mg/kg. The intensity of neurotoxicity and liver dysfunction caused by DLT were significantly increased in a dose-dependent manner. We found that DLT caused the increase of cytosolic superoxide in tissues. Western blot analysis showed that both the expression of p66shc and Ser36 phosphorylated p66shc, which were involved in ROS generation, were increased in tissues treated with DLT. Further investigation showed that DLT treatment resulted in the increase of intracellular ROS accompanied with elevated p66shc expression in different cell lines. And treatment of cells with DLT induced p66shc phosphorylation at Ser36 and the translocation of p66shc from cytoplasm to mitochondria. Moreover, the overexpression of wildtype p66shc caused the increase of DLT-mediated ROS level in SH-SY5Y cells, but cells overexpressing p66shcSer36Ala mutant plasmid had the opposite effect. And p66shc suppression by siRNA blunted DLT-mediated ROS generation. Taken together, our findings indicated p66shc mediated DLT-induced oxidative stress, which may be partly responsible for toxic effects.