Ridaifen G, tamoxifen analog, is a potent anticancer drug working through a combinatorial association with multiple cellular factors

Synthesis of BODIPY FL-tethered ridaifen-B, RID-B-BODIPY, and its localization in cancer cells

We synthesized ridaifen-B boron dipyrromethene (RID-B-BODIPY) using 2-methyl-6-nitro benzoic anhydride (MNBA)-mediated dehydration condensation reaction between amino alkyl-tethered RID and BODIPY FL. Comparative experiments between dicyclohexylcarbodiimide (DCC) and MNBA for their coupling reactions demonstrated that MNBA is an effective condensation reagent for amines and BODIPY FL. A cell staining study with RID-B-BODIPY showed intracellular localization of BODIPY FL fluorescence, attributed to the RID-B structure, indicating the successful development of a tool for analyzing intracellular molecular behavior efficiently.

Emerging roles of hnRNP A2B1 in cancer and inflammation

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing, transactivation of gene expression, and regulation of protein translation. As a core component of the hnRNP complex in mammalian cells, heterogeneous nuclear ribonucleoprotein A2B1 (hnRNP A2B1) participates in and coordinates various molecular events. Given its regulatory role in inflammation and cancer progression, hnRNP A2B1 has become a novel player in immune response, inflammation, and cancer development. Concomitant with these new roles, a surprising number of mechanisms deemed to regulate hnRNP A2B1 functions have been identified, including post-translational modifications, changes in subcellular localization, direct interactions with multiple DNAs, RNAs, and proteins or the formation of complexes with them, which have gradually made hnRNP A2B1 a molecular target for multiple drugs. In light of the rising interest in the intersection between cancer and inflammation, this review will focus on recent knowledge of the biological roles of hnRNP A2B1 in cancer, immune response, and inflammation.

Heterogeneous nuclear ribonucleoprotein A/B: an emerging group of cancer biomarkers and therapeutic targets

Heterogeneous nuclear ribonucleoprotein A/B (hnRNPA/B) is one of the core members of the RNA binding protein (RBP) hnRNPs family, including four main subtypes, A0, A1, A2/B1 and A3, which share the similar structure and functions. With the advance in understanding the molecular biology of hnRNPA/B, it has been gradually revealed that hnRNPA/B plays a critical role in almost the entire steps of RNA life cycle and its aberrant expression and mutation have important effects on the occurrence and progression of various cancers. This review focuses on the clinical significance of hnRNPA/B in various cancers and systematically summarizes its biological function and molecular mechanisms.

Anti-proliferative effect of ridaifen-B on hepatoma cells

Ridaifens (RIDs), a novel series of tamoxifen derivatives, exhibit a potent growth-inhibitory effect against numerous tumor cells regardless of the expression of estrogen receptors, and are thus promising candidates as novel anti-tumor drugs. RID-B is a first generation RIDs, and inhibits the proliferation of several tumor cell lines. However, the potentially growth inhibitory effect of RID-B against hepatoma cells, and the detailed mechanism underlying RID-B-mediated tumor cell death remain to be elucidated. The purpose of the current study was to evaluate the anti-proliferative effect of RID-B against hepatoma cells. The anti-proliferative effect of RID-B against human hepatoma Huh-7 cells was investigated by cell proliferation assay using WST-1 reagent, and caspase-3 activity was evaluated by using specific fluorescent substrate. In addition, DNA fragmentation in Huh-7 cells induced by RID-B was estimated by terminal deoxynucleotidyl transferase dUTP nick-end labelling assay, and binding of RID-B to double-stranded DNA was confirmed by mass spectrometry. RID-B (0.5, 1 and 2 µM) inhibited the growth of Huh-7 cells, seemingly dose-dependently, but did not inhibit the growth of normal primary rat hepatocytes in the same concentration range. Furthermore, the caspase-3 activity of Huh-7 cells was increased by RID-B (0.5 and 5 µM), and the anti-proliferative effect of RID-B (1 µM) on Huh-7 cells was partially suppressed by the addition of the caspase inhibitor, Z-VAD-FMK. Additionally, RID-B (10 µM) directly bound to double-stranded DNA, and the addition of DNA suppressed RID-B-mediated cell growth inhibition and DNA fragmentation in Huh-7 cells. From these data, it may be concluded that RID-B inhibited cell growth and induced apoptosis via activating caspase-3 and binding to DNA directly, leading to DNA fragmentation in hepatoma cells.

Identification of proteins that bind to the neuroprotective agent neoechinulin A

Neoechinulin A is an indole alkaloid with several biological activities. We previously reported that this compound protects neuronal PC12 cells from cytotoxicity induced by the peroxynitrite generator 3-morpholinosydnonimine (SIN-1), but the target proteins and precise mechanism of action of neoechinulin A were unclear. Here, we employed a phage display screen to identify proteins that bind directly with neoechinulin A. Our findings identified two proteins, chromogranin B and glutaredoxin 3, as candidate target binding partners for the alkaloid. QCM analyses revealed that neoechinulin A displays high affinity for both chromogranin B and glutaredoxin 3. RNA interference-mediated depletion of chromogranin B decreased the sensitivity of PC12 cells against SIN-1. Our results suggested chromogranin B is a plausible target of neoechinulin A.