Elevating CDCA3 levels in non-small cell lung cancer enhances sensitivity to platinum-based chemotherapy

Abstract

Platinum-based chemotherapy remains the cornerstone of treatment for most non-small cell lung cancer (NSCLC) cases either as maintenance therapy or in combination with immunotherapy. However, resistance remains a primary issue. Our findings point to the possibility of exploiting levels of cell division cycle associated protein-3 (CDCA3) to improve response of NSCLC tumours to therapy. We demonstrate that in patients and in vitro analyses, CDCA3 levels correlate with measures of genome instability and platinum sensitivity, whereby CDCA3high tumours are sensitive to cisplatin and carboplatin. In NSCLC, CDCA3 protein levels are regulated by the ubiquitin ligase APC/C and cofactor Cdh1. Here, we identified that the degradation of CDCA3 is modulated by activity of casein kinase 2 (CK2) which promotes an interaction between CDCA3 and Cdh1. Supporting this, pharmacological inhibition of CK2 with CX-4945 disrupts CDCA3 degradation, elevating CDCA3 levels and increasing sensitivity to platinum agents. We propose that combining CK2 inhibitors with platinum-based chemotherapy could enhance platinum efficacy in CDCA3low NSCLC tumours and benefit patients.

Elevating CDCA3 Levels Enhances Tyrosine Kinase Inhibitor Sensitivity in TKI-Resistant EGFR Mutant Non-Small-Cell Lung Cancer

“…Given we have previously demonstrated that CDCA3 strongly correlates with platinum-based chemotherapy response in all NSCLC histologies [ 25 ], we next sought to determine whether a similar trend might exist with the response to EGFR TKIs. We evaluated TCGA datasets and correlated relative CDCA3 expression against available WikiPathways [ 31 ] of known measures of TKI resistance.…”

“…Lipofectamine RNAimax (Life Technologies) was used to transfect previously validated [ 24 ] negative control Stealth siRNAs and Stealth siRNAs (siCDCA3-1, sense 5′-ACUGGUGAAACAGCUGAGUGAAGUA-3′, anti-sense 5′-UACUUCACUCAGCUGUUUCACCAGU-3′) to deplete CDCA3 levels (ThermoFisher Scientific). Transfection of CDCA3-FLAG expression construct [ 25 ] was performed using the FuGene HD transfection reagent (Promega Corporation, Annandale, Australia).…”

“…High-content immunofluorescence and imaging for mitotic index were performed as previously described [ 25 ]. Briefly, cells seeded in glass bottom 96-well plates were fixed with 4% paraformaldehyde for 20 min at ambient temperature and permeabilized with 0.1% Trion X-100 in PBS for 5 min.…”

“…The identification of novel biomarkers that are predictive of tumour relapse or TKI resistance is key to improving the health outcomes for NSCLC patients with tumours harbouring EGFR activating mutations. More recently, we have identified novel protein-based NSCLC biomarkers with prognostic potential [ 23 ] including cell division cycle-associated protein-3 (CDCA3) [ 24 , 25 ]. CDCA3, also referred to as trigger of mitosis entry 1 (TOME-1), was first reported as a modulator of cell cycle progression for entry into mitosis from the G2 phase [ 26 ].…”

“…We previously identified that CDCA3 was elevated in NSCLC, and its expression was strongly prognostic and high expression was significantly associated with LUAD [ 24 ]. More recently, we have identified that elevated levels of CDCA3 also correlate with response to platinum-based chemotherapy, whereby CDCA3 high tumours exhibit greater sensitivity to therapy [ 25 ]. Our findings suggest that CDCA3 may be useful as a prognostic or predictive biomarker or potential therapeutic target in NSCLC.…”