Biology subjects

Hsu, F.

Publications and source records attributed to Hsu, F..

4 recordsLinked to original sources

bioRxiv2026

Epigallocatechin gallate and thermal cycling-stimulation synergistically promote apoptosis in A549 cells via endoplasmic reticulum stress-induced calcium ion dysregulation and oxidative stress

Non-small cell lung cancer (NSCLC), as the predominant subtype of lung cancer, presents a considerable clinical challenge due to its high rates of recurrence and the significant adverse effects associated with conventional therapeutic modalities. In response to these challenges, this study explored the new combined anticancer effects of epigallocatechin gallate (EGCG) together with thermal cycling-stimulation (TCS). The findings demonstrated that the combination of EGCG and TCS synergistically decreased the viability of A549 and NCI-H460 NSCLC cells, while exhibiting minimal cytotoxic effects on IMR-90 normal lung fibroblasts. Further investigation revealed that EGCG mitigated the TCS-induced upregulation of heat shock proteins HSP70 and HSP105 and concurrently diminished the expression levels of proteasome subunits. This combined effect disrupted proteostasis, resulting in pronounced endoplasmic reticulum (ER) stress. Subsequently, a positive feedback mechanism was established between inositol 1,4,5-trisphosphate receptor (IP3R)-mediated ER Ca2+ release and excessive reactive oxygen species (ROS) production, ultimately leading the cells to undergo mitochondrial apoptosis. This combined treatment reduces the necessary dosage of EGCG, thereby overcoming limitations related to its poor bioavailability and systemic toxicity, while also preventing the development of thermotolerance induced by TCS. Consequently, this method offers a new and potentially practical therapeutic strategy for treating NSCLC.

Cancer Biology↗

bioRxiv2021

Genome-wide protein-DNA interaction site mapping using a double strand DNA-specific cytosine deaminase

DNA-protein interactions (DPIs) are central to such fundamental cellular processes as transcription and chromosome maintenance and organization. The spatiotemporal dynamics of these interactions dictate their functional consequences; therefore, there is great interest in facile methods for defining the sites of DPI within cells. Here, we present a general method for mapping DPI sites in vivo using the double stranded DNA-specific cytosine deaminase toxin DddA. Our approach, which we term DddA-sequencing (3D-seq), entails generating a translational fusion of DddA to a DNA binding protein of interest, inactivating uracil DNA glycosylase, modulating DddA activity via its natural inhibitor protein, and DNA sequencing for genome-wide DPI detection. We successfully applied this method to three Pseudomonas aeruginosa transcription factors that represent divergent protein families and bind variable numbers of chromosomal locations. 3D-seq offers several advantages over existing technologies including ease of implementation and the possibility to measure DPIs at single-cell resolution.

genetics↗

bioRxiv2020

An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

When bacterial cells come in contact, antagonism mediated by the delivery of toxins frequently ensues. The potential for such encounters to have long-term beneficial consequences in recipient cells has not been investigated. Here we examined the effects of intoxication by DddA, a cytosine deaminase delivered via the type VI secretion system (T6SS) of Burkholderia cenocepacia. Despite its killing potential, we observed that several bacterial species resist DddA and instead accumulate mutations installed by the toxin, indicating that even in the absence of killing, interbacterial toxins can have profound consequences on target populations. Investigation of additional toxins from the deaminase superfamily revealed that mutagenic activity is a common feature of these proteins, including a representative we show targets single-stranded DNA and displays a markedly divergent structure. Our findings suggest that a surprising consequence of antagonistic interactions between bacteria could be the promotion of adaptation via the action of directly mutagenic toxins.

microbiology↗

bioRxiv2017

Rab5 and Alsin regulate stress-activated cytoprotective signaling on mitochondria

Mitochondrial stress response is essential for cell survival, and damaged mitochondria are a hallmark of neurodegenerative diseases. It is thus fundamental to understand how mitochondria relay information within the cell. Here, by investigating mitochondrial-endosome contact sites we made the surprising observation that the small GTPase Rab5 translocates from early endosomes to the outer mitochondrial membrane upon oxidative stress. This is accompanied by an increase in Rab5-positive endosomes in contact with mitochondria. Interestingly, activation of Rab5 on mitochondria depend on the Rab5-GEF ALS2/Alsin, which is encoded by a gene mutated in amyotrophic lateral sclerosis (ALS). Alsin-/- human induced pluripotent stem cell-derived spinal motor neurons cannot relocate Rab5 to mitochondria and display increased susceptibility to oxidative stress. These findings define a novel pathway whereby Alsin catalyzes assembly of the Rab5 endocytic machinery on mitochondria. Defects in stress-sensing by endosomes could be crucial for mitochondrial quality control during the onset of ALS.

cell biology↗