Anti-CDK20 monoclonal antibody, clone 996DU38.2.2

Radiochemoresistance is considered the main cause of local recurrence and distant metastasis in lung cancer. However, the underlying mechanisms of radiochemoresistance remain to be uncovered. In this study, we determine the functions of cell cyclerelated kinase (CDK20) in radiochemoresistance. CDK20 is a newly identified protein kinase, which plays critical roles in cell growth and proliferation in several types of cancer. Using tandem affinity purification technology, we provide evidences that CDK20 binds to the ubiquitin ligase Kelch-like ECH-associated protein 1 (KEAP1), which targets transcriptional factor nuclear factor erythroid-2-related factor 2 (NRF2) for degradation. We show that this interaction is mediated by an evolutionarily conserved ETGE motif on CDK20. Furthermore, we demonstrate that CDK20 competes with NRF2 for KEAP1 binding, enhances the transcriptional activity of NRF2 and lowers the cellular reactive oxygen species level. Moreover, CDK20-depleted cells display impaired cell proliferation, defective G2/M arrest and increased radiochemosensitivity in lung cancer. These phenotypes induced by CDK20 knockdown are partially dependent on NRF2 inactivation. More importantly, CDK20 is overexpressed in human lung cancer tissues, as determined by immunostaining. Collectively, our results suggest that CDK20 positively modulate the KEAP1-NRF2 cytoprotective pathway to regulate tumor progression and radiochemoresistance, implying that CDK20 is a novel, promising therapeutic target for lung cancer.

The complete coding sequence of one pig gene, CDK20, was amplified by RT-PCR. Sequence analysis revealed that the porcine CDK20 gene encodes a protein of 343 amino acids which has high homology with the cyclin-dependent kinase 20 (CDK20) of eight species: cattle (96%), giant panda (96%), mouse (96%), rabbit (96%), rat (96%), dog (95%), human (93%) and Sumatran orangutan (93%). This novel porcine gene was then deposited into the GenBank database and finally assigned to GenelD: 100157041. This gene is structured in eight exons and seven introns as revealed by computer-assisted analysis. Polymorphism analysis revealed that there was a TIC substitution at the position of 96-bp of exon 4 and this led to the amino acid alteration from the Arg residue to the Cys residue. PCR-Alu I-RFLP analysis indicated that eight pig breeds displayed obvious genotype and allele frequency differences at this mutation locus. Association analysis showed that this polymorphic locus was significantly associated with the litter size of all parities in Large White and Landrace sows. Therefore, CDK20 gene could be a useful candidate gene for increasing the litter size of pigs. These data serve as a foundation for further insight into the porcine CDK20 gene.