Magic™ Anti-MTOR (Phospho S2481) monoclonal antibody, clone FQS538(O)

Loss of the tumor suppressor NF1 leads to activation of RAS effector pathways, which are therapeutically targeted by inhibition of mTOR (mTORi) or MEK (MEKi). However, therapeutic inhibition of RAS effectors leads to the development of drug resistance and ultimately disease progression. To investigate molecular signatures in the context of NF1 loss and subsequent acquired drug resistance, we analyzed the exomes, transcriptomes, and kinomes of Nf1-mutant mouse tumor cell lines and derivatives of these lines that acquired resistance to either MEKi or mTORi. Biochemical comparisons of this unique panel of tumor cells, all of which arose in Nf1(+/-) mice, indicate that loss of heterozygosity of Nf1 as an initial genetic event does not confer a common biochemical signature or response to kinase inhibition. Although acquired drug resistance by Nf1-mutant tumor cells was accompanied by altered kinomes and irreversibly altered transcriptomes, functionally in multiple Nf1-mutant tumor cell lines, MEKi resistance was a stable phenotype, in contrast to mTORi resistance, which was reversible. Collectively, these findings demonstrate that Nf1-mutant tumors represent a heterogeneous group biochemically and undergo broader remodeling of kinome activity and gene expression in response to targeted kinase inhibition.

Osteoarthritis (OA) is one of the most painful and widespread chronic degenerative joint diseases and is characterized by destructed articular cartilage and inflamed joints. Previously, our findings indicated that circular RNA ciRS-7 (ciRS-7)/microRNA 7 (miR-7) axis is abnormally expressed in OA, and regulates proliferation, inflammatory responses, and apoptosis of interleukin-1 beta (1L-1 beta)-stimulated chondrocytes. However, its underlying role in OA remains unknown. In this study, we first validated cartilage degradation and defection of autophagy in samples of OA patients. IL-1 beta initially stimulated autophagy of chondrocytes, and ultimately significantly suppressed autophagy. Upregulated ciRS-7/down-regulated miR-7 aggravated IL-1 beta-induced cartilage degradation, and restrained autophagy in vitro. Gene sequencing and bioinformatics analysis performed on a control group, IL-1 beta group, and IL-1 beta+miR-7-mimics group demonstrated that seven of the most significant mRNA candidates were enriched in the interleukin-17 (11-17) signaling pathway. Increased IL-17A levels were also observed by qRT-PCR and ELISA. In addition, it was revealed that the ciRS-7/miR-7 axis ameliorated cartilage degradation and defection of autophagy by PI3K/AKT/mTOR activation in IL-1 beta-induced chondrocytes. Furthermore, an OA model was established in rats with medial meniscus destabilization. miR-7-siRNA-expressing lentiviruses alleviated surgical resection-induced cartilage destruction of OA mice, whereas miR-7 mimics worsened the effects. Thus, these findings revealed that the mechanism of the ciRS-7/miR-7 axis involved regulating OA progression and provided valuable directions for OA treatment.