XAF1 drives apoptotic switch of endoplasmic reticulum stress response through destabilization of GRP78 and CHIP.

X-linked inhibitor of apoptosis-associated factor-1 (XAF1) is a stress-inducible tumor suppressor that is commonly inactivated in many human cancers. Despite accumulating evidence for the pro-apoptotic role for XAF1 under various stressful conditions, its involvement in endoplasmic reticulum (ER) stress response remains undefined. Here, we report that XAF1 increases cell sensitivity to ER stress and acts as a molecular switch in unfolded protein response (UPR)-mediated cell-fate decisions favoring apoptosis over adaptive autophagy.

XAF1 destabilizes estrogen receptor α through the assembly of a BRCA1-mediated destruction complex and promotes estrogen-induced apoptosis.

X-linked inhibitor of apoptosis-associated factor 1 (XAF1) is a pro-apoptotic tumor suppressor that is frequently inactivated in multiple human cancers. However, its candidacy as a suppressor in the pathogenesis of breast cancer remains undefined. Here, we report that XAF1 acts as a molecular switch in estrogen (E2)-mediated cell-fate decisions favoring apoptosis over cell proliferation.

XAF1 directs glioma response to temozolomide through apoptotic transition of autophagy by activation of ATM-AMPK signaling.

Background: X-linked inhibitor of apoptosis-associated factor 1 (XAF1) is a tumor suppressor that is commonly inactivated in multiple human cancers. However, its role in the pathogenesis and therapeutic response of glioma is poorly characterized.

Methods: XAF1 activation by temozolomide (TMZ) and its effect on TMZ cytotoxicity were defined using luciferase reporter, flow cytometry, and immunofluorescence assays.

Mitochondrial relocation of a common synthetic antibiotic: A non-genotoxic approach to cancer therapy.

Tumor recurrence as a result of therapy-induced nuclear DNA lesions is a major issue in cancer treatment. Currently, only a few examples of potentially non-genotoxic drugs have been reported. Mitochondrial re-localization of ciprofloxacin, one of the most commonly prescribed synthetic antibiotics, is reported here as a new approach.

NORE1A directs apoptotic switch of TNF signaling through reciprocal modulation of ITCH-mediated destruction of TNFRI and BAX.

NORE1A (RASSF5) is a tumor suppressor of the Ras-association domain family (RASSF) that is commonly inactivated in multiple human cancers. However, the molecular mechanism underlying its growth inhibition function remains largely undefined. Here we report that NORE1A antagonizes tumor necrosis factor receptor I (TNFRI) through the assembly of ITCH-mediated destruction complex to suppress TNF-NF-κB signaling and tumorigenesis.

XAF1 forms a positive feedback loop with IRF-1 to drive apoptotic stress response and suppress tumorigenesis.

X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) is a proapoptotic tumor suppressor that is frequently inactivated in multiple human cancers. However, the molecular basis for the XAF1-mediated growth inhibition remains largely undefined. Here, we report that XAF1 forms a positive feedback loop with interferon regulatory factor-1 (IRF-1) and functions as a transcriptional coactivator of IRF-1 to suppress tumorigenesis.

PLK1-Targeted Fluorescent Tumor Imaging with High Signal-to-Background Ratio.

As significantly expressed during cell division, polo-like kinase 1 (PLK1) plays crucial roles in numerous mitotic events and has attracted interest as a potential therapeutic marker in oncological drug discovery. We prepared two small molecular fluorescent probes, 1 and 2, conjugated to SBE13 (a type II PLK1 inhibitor) to investigate the PLK1-targeted imaging of cancer cells and tumors. Enzymatic docking studies, molecular dynamics simulations, and in vitro and in vivo imaging experiments all supported the selective targeting and visualization of PLK1 expressing cells by probes 1 and 2, and probe 2 was successfully demonstrated to image PLK1-upregulated tumors with remarkable signal-to-background ratios.

RASSF1A Directly Antagonizes RhoA Activity through the Assembly of a Smurf1-Mediated Destruction Complex to Suppress Tumorigenesis.

RASSF1A is a tumor suppressor implicated in many tumorigenic processes; however, the basis for its tumor suppressor functions are not fully understood. Here we show that RASSF1A is a novel antagonist of protumorigenic RhoA activity. Direct interaction between the C-terminal amino acids (256-277) of RASSF1A and active GTP-RhoA was critical for this antagonism.

PPARδ promotes oncogenic redirection of TGF-β1 signaling through the activation of the ABCA1-Cav1 pathway.

TGF-β1 plays biphasic functions in prostate tumorigenesis, inhibiting cell growth at early stages but promoting malignant progression at later stages. However, the molecular basis for the oncogenic conversion of TGF-β1 function remains largely undefined. Here, we demonstrate that PPARδ is a direct transcription target of TGF-β1 and plays a critical role in oncogenic redirection of TGF-β1 signaling.