StarD13 negatively regulates invadopodia formation and invasion in high-grade serous (HGS) ovarian adenocarcinoma cells by inhibiting Cdc42

YAP signaling orchestrates the endothelin-1-guided invadopodia formation in high-grade serous ovarian cancer

The high-grade serous ovarian cancer (HG-SOC) is a notoriously challenging disease, characterized by a rapid peritoneal dissemination. HG-SOC cells leverage actin-rich membrane protrusions, known as invadopodia, to degrade the surrounding extracellular matrix (ECM) and invade, initiating the metastatic cascade. In HG-SOC, the endothelin-1 (ET-1)/endothelin A receptor (ETAR)-driven signaling coordinates invadopodia activity, however how this axis integrates pro-oncogenic signaling routes, as YAP-driven one, impacting on the invadopodia-mediated ECM degradation and metastatic progression, deserves a deeper investigation. Herein, we observed that downstream of the ET-1/ET-1R axis, the RhoC and Rac1 GTPases, acting as signaling intermediaries, promote the de-phosphorylation and nuclear accumulation of YAP. Conversely, the treatment with the dual ETA/ETB receptor antagonist, macitentan, inhibits the ET-1-driven YAP activity. Similarly, RhoC silencing, or cell transfection with a dominant inactive form of Rac1, restores YAP phosphorylation. Mechanistically, the ET-1R/YAP signal alliance coordinates invadopodia maturation into ECM-degrading structures, indicating how such ET-1R-guided protein network represents a route able to enhance the HG-SOC invasive potential. At functional level, we found that the interconnection between the ET-1R/RhoC and YAP signals is required for MMP-2 and MMP-9 proteolytic functions, cell invasion, and cytoskeleton architecture changes, supporting the HG-SOC metastatic strength. In HG-SOC patient-derived xenografts (PDX) macitentan, turning-off the invadopodia regulators RhoC/YAP, halts the metastatic colonization. ET-1R targeting, hindering the YAP activity, weakens the invadopodia machinery, embodying a promising therapeutic avenue to prevent peritoneal dissemination in HG-SOC.

Targeted therapy in high grade serous ovarian Cancer: A literature review

Ovarian cancer continues to have a high mortality rate despite therapeutic advances. Traditionally, treatment has focused on surgery followed by systemic platinum- based chemotherapy. Unfortunately, most patients develop resistance to platinum agents, highlighting the need for targeted therapies. PARP inhibitors and anti-angiogenic agents, such as bevacizumab, have more recently changed upfront therapy. Unfortunately, other targeted therapies including immunotherapy have not seen the same success. Emerging therapeutic targets and modalities such as small molecule tyrosine kinase inhibitors, lipid metabolism targeting agents, gene therapy, ribosome targeted drugs as well as several other therapeutic classes have been and are currently under investigation. In this review, we discuss targeted therapies in high grade serous ovarian cancer from preclinical studies to phase III clinical trials.

Unravelling molecular dynamics in living cells: Fluorescent protein biosensors for cell biology

Genetically encoded, fluorescent protein (FP)-based Förster resonance energy transfer (FRET) biosensors are microscopy imaging tools tailored for the precise monitoring and detection of molecular dynamics within subcellular microenvironments. They are characterised by their ability to provide an outstanding combination of spatial and temporal resolutions in live-cell microscopy. In this review, we begin by tracing back on the historical development of genetically encoded FP labelling for detection in live cells, which lead us to the development of early biosensors and finally to the engineering of single-chain FRET-based biosensors that have become the state-of-the-art today. Ultimately, this review delves into the fundamental principles of FRET and the design strategies underpinning FRET-based biosensors, discusses their diverse applications and addresses the distinct challenges associated with their implementation. We place particular emphasis on single-chain FRET biosensors for the Rho family of guanosine triphosphate hydrolases (GTPases), pointing to their historical role in driving our understanding of the molecular dynamics of this important class of signalling proteins and revealing the intricate relationships and regulatory mechanisms that comprise Rho GTPase biology in living cells.

Loss of STARD13 contributes to aggressive phenotype transformation and poor prognosis in papillary thyroid carcinoma

PURPOSE

StAR Related Lipid Transfer Domain Containing 13 (STARD13) serves as a tumor suppressor and has been characterized in several types of malignancies. However, the role and the molecular mechanism of STARD13 in regulating the progression of papillary thyroid carcinoma (PTC) remain underexplored.

METHODS

The gene expression and clinical information of thyroid cancer were downloaded using "TCGAbiolinks" R package. Quantitative PCR and immunohistochemical staining were conducted to detect the expression of STARD13 in clinical tumor and adjacent non-tumor samples. Wound-healing assay, Transwell assay and 3D spheroid invasion assay were performed to evaluate the migratory and invasive capacities of PTC cells. Cell proliferation ability was determined by CCK-8 assay, colony formation assay and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay. The alterations of indicated proteins were detected by Western blotting.

RESULTS

In the present study, we found that STARD13 was significantly underexpressed in PTC, which was correlated with poor prognosis. Downregulation of STARD13 might be due to methylation of promoter region. Loss-and gain-of-function experiments demonstrated that STARD13 impeded migratory and invasive capacities of PTC cells in vitro and in vivo. In addition, we found that STARD13 regulated the morphology of PTC cells and inhibited epithelial-mesenchymal transition (EMT).

CONCLUSION

Our results suggest that STARD13 acts as a metastasis suppressor and might be a potential therapeutic target in PTC.

EFHD1, a novel mitochondrial regulator of tumor metastasis in clear cell renal cell carcinoma

The biological function of many mitochondrial proteins in mechanistic detail has not been well investigated in clear cell renal cell carcinoma (ccRCC). A seven-mitochondrial-gene signature was generated by Lasso regression analysis to improve the prediction of prognosis of patients with ccRCC, using The Cancer Genome Atlas and Clinical Proteomic Tumor Analysis Consortium cohort. Among those seven genes, EFHD1 is less studied and its role in the progression of ccRCC remains unknown. The decreased expression of EFHD1 was validated in clinical samples and was correlated with unfavorable outcome. Overexpression of EFHD1 in ccRCC cells resulted in the reduction of mitochondrial Ca²⁺ , and the inhibition of cell migration and invasion in vitro and tumor metastasis in vivo. Mechanistically, EFHD1 physically bound to the core mitochondrial calcium transporter (mitochondrial calcium uniporter, MCU) through its N-terminal domain. The interaction between EFHD1 and MCU suppressed the uptake of Ca²⁺ into mitochondria, and deactivated the Hippo/YAP signaling pathway. Further data revealed that the ectopic expression of EFHD1 upregulated STARD13 to enhance the phosphorylation of YAP protein at Ser-127. The knockdown of STARD13 or the overexpression of MCU partly abrogated the EFHD1-mediated induction of phosphorylation of YAP at Ser-127 and suppression of cell migration. Taken together, the newly identified EFHD1-MCU-STARD13 axis participates in the modulation of the Hippo/YAP pathway and serves as a novel regulator in the progression of ccRCC.