Josephin domain containing 2(JOSD2)promotes lung cancer by inhibiting LKB1(Liver kinase B1)activity

Non-small cell lung cancer(NSCLC)ranks as one of the leading causes of cancer-related deaths worldwide.Despite the prominence and effectiveness of kinase-target therapies in NSCLC treatment,these drugs are suitable for and beneficial to a mere~30%of NSCLC patients.Consequently,the need for novel strategies addressing NSCLC remains pressing.Deubiquitinases(DUBs),a group of diverse enzymes with well-defined catalytic sites that are frequently overactivated in cancers and associated with tumorigenesis and regarded as promising therapeutic targets.Nevertheless,the mechanisms by which DUBs promote NSCLC remain poorly understood.Through a global analysis of the 97 DUBs’contribution to NSCLC survival possibilities using The Cancer Genome Atlas(TCGA)database,we found that high expression of Josephin Domain-containing protein 2(JOSD2)predicted the poor prognosis of patients.Depletion of JOSD2 significantly impeded NSCLC growth in both cell/patient-derived xenografts in vivo.Mechanically,we found that JOSD2 restricts the kinase activity of LKB1,an important tumor suppressor generally inactivated in NSCLC,by removing K6-linked polyubiquitination,an action vital for maintaining the integrity of the LKB1-STRAD-MO25 complex.Notably,we identified the first small-molecule inhibitor of JOSD2,and observed that its pharmacological inhibition significantly arrested NSCLC proliferation in vitro/in vivo.Our findings highlight the vital role of JOSD2 in hindering LKB1 activity,underscoring the therapeutic potential of targeting JOSD2 in NSCLC,especially in those with inactivated LKB1,and presenting its inhibitors as a promising strategy for NSCLC treatment.

Deubiquitinase JOSD2 stabilizes YAP/TAZ to promote cholangiocarcinoma progression

Cholangiocarcinoma(CCA)has emerged as an intractable cancer with scanty therapeutic regimens.The aberrant activation of Yes-associated protein(YAP)and transcriptional co-activator with PDZ-binding motif(TAZ)are reported to be common in CCA patients.However,the underpinning mechanism remains poorly understood.Deubiquitinase(DUB)is regarded as a main orchestrator in maintaining protein homeostasis.Here,we identified Josephin domain-containing protein 2(JOSD2)as an essential DUB of YAP/TAZ that sustained the protein level through cleavage of polyubiquitin chains in a deubiquitinase activity-dependent manner.The depletion of JOSD2 promoted YAP/TAZ proteasomal degradation and significantly impeded CCA proliferation in vitro and in vivo.Further analysis has highlighted the positive correlation between JOSD2 and YAP abundance in CCA patient samples.Collectively,this study uncovers the regulatory effects of JOSD2 on YAP/TAZ protein stabilities and profiles its contribution in CCA malignant progression,which may provide a potential intervention target for YAP/TAZ-related CCA patients.

Targeting slug-mediated non-canonical activation of c-Met to overcome chemo-resistance in metastatic ovarian cancer cells

Metastasis-associated drug resistance accounts for high mortality in ovarian cancer and remains to be a major barrier for effective treatment. In this study, SKOV3/T4, a metastatic subpopulation of ovarian cancer SKOV3 cells, was enriched to explore potential interventions against metastaticassociated drug resistance. Quantitative genomic and functional analyses were performed and found that slug was significantly increased in the SKOV3/T4 subpopulation and contributed to the high resistance of SKOV3/T4. Further studies showed that slug activated c-Met in a ligand-independent manner due to elevated levels of fibronectin and provoked integrin α V function, which was confirmed by the significant correlation of slug and p-Met levels in 121 ovarian cancer patient samples. Intriguingly,c-Met inhibitor(s) exhibited greatly enhanced anti-cancer effects in slug-positive ovarian cancer models both in vitro and in vivo. Additionally, IHC analyses revealed that slug levels were highly correlated with reduced survival of ovarian cancer patients. Taken together, this study not only uncovers the critical roles of slug in drug resistance in ovarian cancer but also highlights a promising therapeutic strategy by targeting the noncanonical activation of c-Met in slug-positive ovarian cancer patients with poor prognosis.