ABSTRACT
KDM5A and KDM5B histone-demethylases are overexpressed in many cancers and have been involved in drug tolerance. Here, we describe that KDM5A, together with KDM5B, contribute to replication stress (RS) response and tolerance. First, they positively regulate RRM2, the regulatory subunit of ribonucleotide reductase. Second, they are required for optimal levels of activated Chk1, a major player of the intra-S phase checkpoint that protects cells from RS. We also found that KDM5A is enriched at ongoing replication forks and associates with both PCNA and Chk1. Because RRM2 is a major determinant of replication stress tolerance, we developed cells resistant to HU, and show that KDM5A/B proteins are required for both RRM2 overexpression and tolerance to HU. Altogether, our results indicate that KDM5A/B are major players of RS management. They also show that drugs targeting the enzymatic activity of KDM5 proteins may not affect all cancer-related consequences of KDM5A/B overexpression.
Subject(s)
DNA Damage/drug effects , DNA Replication/drug effects , Drug Tolerance , Hydroxyurea/pharmacology , Jumonji Domain-Containing Histone Demethylases/metabolism , Nuclear Proteins/metabolism , Repressor Proteins/metabolism , Retinoblastoma-Binding Protein 2/metabolism , Cell Line, Tumor , Checkpoint Kinase 1/metabolism , DNA Repair , Drug Tolerance/genetics , Gene Expression Regulation , Histones/metabolism , Humans , Jumonji Domain-Containing Histone Demethylases/genetics , Nuclear Proteins/genetics , Repressor Proteins/genetics , Retinoblastoma-Binding Protein 2/genetics , Ribonucleoside Diphosphate Reductase/genetics , Signal Transduction/drug effectsABSTRACT
The anti-Müllerian hormone (AMH) belongs to the TGF-ß family and plays a key role during fetal sexual development. Various reports have described the expression of AMH type II receptor (AMHRII) in human gynecological cancers including ovarian tumors. According to qRT-PCR results confirmed by specific In-Situ Hybridization (ISH) experiments, AMHRII mRNA is expressed in an extremely restricted number of normal tissues. By performing ISH on tissue microarray of solid tumor samples AMHRII mRNA was unexpectedly detected in several non-gynecological primary cancers including lung, breast, head and neck, and colorectal cancers. AMHRII protein expression, evaluated by immunohistochemistry (IHC) was detected in approximately 70% of epithelial ovarian cancers. Using the same IHC protocol on more than 900 frozen samples covering 18 different cancer types we detected AMHRII expression in more than 50% of hepato-carcinomas, colorectal, lung, and renal cancer samples. AMHRII expression was not observed in neuroendocrine lung tumor samples nor in non-Hodgkin lymphoma samples. Complementary analyses by immunofluorescence and flow cytometry confirmed the detection of AMHRII on a panel of ovarian and colorectal cancers displaying comparable expression levels with mean values of 39,000 and 50,000 AMHRII receptors per cell, respectively. Overall, our results suggest that this embryonic receptor could be a suitable target for treating AMHRII-expressing tumors with an anti-AMHRII selective agent such as murlentamab, also named 3C23K or GM102. This potential therapeutic intervention was confirmed in vivo by showing antitumor activity of murlentamab against AMHRII-expressing colorectal cancer and hepatocarcinoma Patient-Derived tumor Xenografts (PDX) models.
