Heat shock proteins (HSPs) play crucial roles in human endothelial cell functions such as migration and angiogenesis. However, human HSP dynamics under stress conditions such as heat shock (HS) and hypoxia in human endothelial cells (ECs) are enigmatic, and the characteristics of HSPs in ECs after exposure to thermal stress and a low-oxygen environment are unknown. We hypothesized that ECs adapt to HS and hypoxia by modulating chaperome oligomerization and that HSP70 is a major determinant of the endothelial phenotype. HSP70 inhibition with VER-155008 or YM-1 in primary human endothelial cells decreases EC proliferation, migration, and angiogenesis at baseline and after heat shock recovery. We showed that vascular-independent HSC/P70 multimeric complexes in primary human veins (HUVEC) and coronary artery ECs (HCAEC) accumulate after HS and are decreased by hypoxia. HS recovery increases the number of HSP90 dimers, inducible HSP70, and HSP40 macromolecular complexes, whereas HSC70 returns to baseline. We demonstrated that the HS response and hypoxia regulate HSPs through a new layer of complexity, oligomerization, in addition to classical cochaperone/NEF interactions. The biphasic temporal oligomerization of molecular chaperones in the recovery phase provides a novel face of the heat shock response. In addition, shifts in the subcellular location and upregulation of HSP70 were also observed here. The decrease in HSP expression caused by hypoxia raises the possibility that decreased chaperone power contributes to the endothelial dysfunction found in atherosclerosis, thrombosis, and cancer. Together, these results show that HSP70 is pivotal to the healthy endothelial response in veins and coronary arteries, and we revealed human HSP dynamics in the vascular response to proteotoxic stress.

Rare sarcomas present significant treatment challenges compared to more prevalent soft tissue sarcomas due to limited treatment options and a poor understanding of their biology. This study investigates a unique case of penile sarcoma, providing a comprehensive morphological and molecular analysis. Through the creation of experimental patient-derived models—including patient-derived xenograft (PDX), 3D, and monolayer primary cultures—we successfully replicated crucial molecular traits observed in the patient’s tumor, such as smooth muscle actin and CD99 expression, along with specific mutations in genes like TSC2 and FGFR4. These models are helpful in assessing the potential for an in-depth exploration of this tumor’s biology. This comprehensive approach holds promise in identifying potential therapeutic avenues for managing this exceedingly rare soft tissue sarcoma.