Biology subjects

Wang, S. Z.

Publications and source records attributed to Wang, S. Z..

4 recordsLinked to original sources

bioRxiv2024

SARS-COV-2 nucleocapsid protein hijacks multiple components of the host nuclear transport machinery for distinct functions

Many viruses target the host nuclear transport machinery to traffic their own proteins or restrict trafficking of host cargo, including mediators of antiviral immune signalling. Nucleocapsid (N) proteins from several coronaviruses traffic to the nucleus/nucleolus, with roles in cell cycle regulation. While N-protein from severe acute respiratory syndrome virus 2 (SARS-COV-2), the causative agent of the global COVID-19 pandemic, is widely reported to localise to the cytoplasm, we identify multiple, functionally distinct interactions of N-protein with the hosts nuclear transport machinery. Using quantitative cell imaging, including fluorescence recovery after photobleaching, and protein-protein interaction analysis, we describe a sub-population of SARS-COV-2 N-protein that localises more diffusely between the nucleus and cytoplasm, undergoes active nuclear import, and re-localises nuclear import receptors (karyopherins) KPNB1 and KPNA2 to the nucleus and cytoplasm, respectively. Truncation analyses identify at least two distinct KPNA2/KPNB1 binding sites located in the N-terminal and C-terminal regions of N-protein. Interestingly, while mutation of K/R-rich sites within these domains reduces KPNA2/KPNB1 binding and disables re-localisation of KPNA2, re-localisation of KPNB1 and nuclear import of N-protein remain intact, indicating that these are molecularly and functionally distinct mechanisms. siRNA knockdown confirms a role for KPNB1 in N-protein nuclear trafficking, while KPNA2 binding and mislocalisation may be antagonistic. Thus, SARS-COV-2 N-protein binds to karyopherins via multiple distinct sites to facilitate import and other functions.

microbiology↗

bioRxiv2024

Connexin 43 drives glioblastoma cancer stem cell phenotypes through a WNK lysine-deficient protein kinase 1-c-MYC signaling axis

The coordination of cellular processes such as growth and survival relies on communication between cells through gap junctions. Gap junction intercellular communication is driven by connexin proteins, which also mediate protein-protein interactions and communication with the extracellular space via hemichannels. Despite their essential roles, connexin function in cancer is context dependent, with connexin 43 (Cx43) reported to both promote and suppress tumor growth in glioblastoma, the most common primary malignant brain tumor. Here, we detect expression of Cx43 in glioblastoma patient-derived cancer stem cells and demonstrate that Cx43 is essential for their survival and self-renewal. Mechanistically, depletion of Cx43 reduces c-MYC expression through reduced levels of the upstream mediator WNK lysine-deficient protein kinase 1 (WNK1). Depletion of WNK1 phenocopies Cx43 knockdown and reduces MYC expression and tumor growth. Together, these results define a novel signaling axis downstream of Cx43 that promotes tumor growth and cancer stem cell phenotypes in glioblastoma.

cancer biology↗

bioRxiv2024

miR-644a is a tumor cell-intrinsic mediator of sex bias in glioblastoma

BackgroundBiological sex is an important risk factor for glioblastoma (GBM), with males having a higher incidence and poorer prognosis. The mechanisms for this sex bias are thought to be both tumor intrinsic and tumor extrinsic. MicroRNAs (miRNAs), key post-transcriptional regulators of gene expression, have been previously linked to sex differences in various cell types and diseases, but their role in the sex bias of GBM remains unknown. MethodsWe leveraged previously published paired miRNA and mRNA sequencing of 39 GBM patients (22 male, 17 female) to identify sex-biased miRNAs. We further interrogated a separate single-cell RNA sequencing dataset of 110 GBM patients to examine whether differences in miRNA target gene expression were tumor cell intrinsic or tumor cell extrinsic. Results were validated in a panel of patient-derived cell models. ResultsWe identified 10 sex-biased miRNAs (adjusted < 0.1), of which 3 were more highly expressed in males and 7 more highly expressed in females. Of these, miR-644a was higher in females, and increased expression of miR-644a target genes was significantly associated with decreased overall survival (HR 1.3, p = 0.02). Furthermore, analysis of an independent single-cell RNA sequencing dataset confirmed sex-specific expression of miR-644a target genes in tumor cells (p < 10-15). Among patient derived models, miR-644a was expressed a median of 4.8-fold higher in females compared to males. ConclusionsOur findings implicate miR-644a as a candidate tumor cell-intrinsic regulator of sex-biased gene expression in GBM. Key PointsO_LImiR-644a is more highly expressed in female GBM patients. C_LIO_LILower miR-644a target gene expression is associated with improved overall survival. C_LIO_LImiR-644a target genes are higher in male GBM cells but not in other cell types. C_LI Importance of the StudyMicroRNAs (miRNAs) are non-coding RNAs that regulate gene expression at the post-transcriptional level and were previously linked to glioblastoma (GBM) growth and therapeutic resistance. miRNAs play a role in the sex bias of various cell types and diseases, but how miRNAs contribute to sex differences in GBM is not well elucidated. We show that 10 miRNAs are differentially expressed between males and females and identify miR-644a as more highly expressed in female GBM patients. Using single-cell RNA-seq data, we demonstrate that sex differences in miR-644a target gene expression are tumor cell-intrinsic. Likewise, decreased miR-644a target gene expression is associated with improved overall patient survival. Our findings reveal miR-644a as a novel sex-biased miRNA in GBM, and a possible target for sex-specific precision therapies with limited collateral damage.

cancer biology↗

bioRxiv2023

Tumor cell-derived spermidine promotes a pro-tumorigenic immune microenvironment in glioblastoma via CD8+ T cell inhibition

The glioblastoma microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can directly impact the immune system, but the mechanisms driving these interactions are not completely clear. Here we demonstrate that the polyamine metabolite spermidine is elevated in the glioblastoma tumor microenvironment. Exogenous administration of spermidine drives tumor aggressiveness in an immune-dependent manner in pre-clinical mouse models via reduction of CD8+ T cell frequency and phenotype. Knockdown of ornithine decarboxylase, the rate-limiting enzyme in spermidine synthesis, did not impact cancer cell growth in vitro but did result in extended survival. Furthermore, glioblastoma patients with a more favorable outcome had a significant reduction in spermidine compared to patients with a poor prognosis. Our results demonstrate that spermidine functions as a cancer cell-derived metabolite that drives tumor progression by reducing CD8+T cell number and function.

cancer biology↗