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Biology subjects

Hassel, C.

Publications and source records attributed to Hassel, C..

2 recordsLinked to original sources

The loss-of-function of SOCS2 increases the inflammatory response to Staphylococcus aureus infection

The involvement of suppressor of cytokine signaling (SOCS)2 in anti-infective bacterial immunity remains largely undetermined compared to other members of the SOCS family. We developed a mouse model expressing the loss of function R96C SOCS2 point mutation to characterize the response of macrophages to Staphylococcus aureus and its TLR-ligand derivatives. The model resumes observations of gigantism done in Socs2-/- mice. Stimulation of bone-marrow-derived macrophages with various TLR-2 ligands showed upregulation of the pro-inflammatory cytokines IL-6 and TNF- production only in cytokine-modulating environments that promote SOCS2 expression. Using this model, we showed that SOCS2 protein reduces STAT-5 phosphorylation in a short time frame upon TLR engagement. When SOCS2 is ablated, neutrophil and F4/80int Ly6C+ inflammatory macrophage recruitment, as well as IFN-{gamma} and IL-10 concentrations are significantly increased upon S. aureus peritoneal infection. By lowering the pro-inflammatory environment, SOCS2 favors better healing during a systemic infection caused by S. aureus.

immunology↗

Novel epigenetic-metabolic inhibitor combination treatment blocks platinum-induced ovarian cancer stem cell enrichment

High grade serous ovarian cancer (HGSOC) is the most common and aggressive type of ovarian cancer. Platinum resistance is a common occurrence in HGSOC and a main cause of tumor relapse resulting in high patient mortality rates. Recurrent OC is enriched in aldehyde dehydrogenase (ALDH)+ ovarian cancer stem cells (OCSCs), which are resistant to platinum agents. We demonstrated that acute platinum treatment induced a DNA damage-dependent decrease in BRCA1 levels. In a parallel response associated with G2/M arrest, platinum treatment also induced an increase in expression of NAMPT, the rate limiting regulator of NAD+ production from the salvage pathway, and levels of NAD+, the cofactor required for ALDH activity. Concurrent inhibition of DNA methyltransferases (DNMTs) and NAMPT synergistically abrogated the platinum-induced increase in OCSCs. Combining pharmacological inhibitors of DNMT and NAMPT with carboplatin reduced tumorigenesis and OCSC percentage in vivo. We conclude that both epigenetic and metabolic alterations lead to platinum induced OCSC enrichment, providing preclinical evidence that in the neoadjuvant setting, combining DNMT and NAMPT inhibitors with platinum has the potential to reduce OC recurrence and avert the development of platinum resistance.

cancer biology↗