Overexpression of TK1 and CDK9 in plasma-derived exosomes is associated with clinical resistance to CDK4/6 inhibitors in metastatic breast cancer patients
Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) improve progression-free survival (PFS) in patients with hormone receptor-positive (HR+) advanced breast cancer. However, a better knowledge of predictive biomarkers of response and resistance to CDK4/6i is needed. Therefore, the present article addresses the role of the mRNA expression of thymidine kinase 1 (TK1), CDK4, 6 and 9 in plasma-derived exosomes and their relevance in the pharmacologic activity of CDK4/6i.
Blood samples of 40 HR+/HER2- advanced breast cancer patients were collected before (T0) the administration of palbociclib plus hormonal therapy and after 3 months (T1). RNA was isolated from exosomes and analysed for the expression of TK1, CDK 4, 6 and 9 by digital droplet PCR (ddPCR).
A higher value of TK1 copies/ml at baseline (T0) was significantly associated with the number of previous lines of chemotherapy (p = 0.009). In patients with PD, a significant increase was observed in the number of copies/ml of TK1 (p = 0.01) and CDK9 (p = 0.03) comparing T1 vs. T0 values. No significant correlations between response to treatment and clinical parameters were found at univariate analysis. High baseline CDK4 expression was significantly correlated with longer PFS in patients treated with fulvestrant + palbociclib (low versus high: 6.45 months vs. not reached, p = 0.01).
The present study demonstrates that, in plasma-derived exosomes, high baseline CDK4 mRNA levels are associated with response to palbociclib plus hormonal therapy, while the increase in TK1 and CDK9 mRNA copies/ml is associated with clinical resistance.
KeywordsTK1 CDK4/6/9 Metastatic breast cancer CDK4/6 inhibitors Plasma-derived exosomes Predictive biomarkers
MDR, IB, SC, ER, CDA, LD, DC, GG, LF, BS, SF, MG, CS, AGN, MR, AF, RM, AF, and RD made substantial contributions to conception and design. MDR, SC, ER, LF, GG, SF, and RD made substantial contributions to the laboratory analysis and interpretation of data. IB, CDA, LD, DC, BS, MG, CS, AGN, MR, AF, and AF made substantial contributions to the acquisition of clinical data and their interpretation. RM, SC, and LF performed the statistical analysis. MDR, IB, SC, ER, LF, GG, AF, and RD have been involved in drafting the manuscript. MDR, IB, MG, CS, AGN, MR, AF, GG, RM, AF, and RD have been involved in revising the paper critically for important intellectual content. All authors gave their final approval of the version to be published. Each author participated sufficiently in the work to take public responsibility for appropriate portions of its content. All authors agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. RD is responsible for the financial support for the project leading to this publication.
RD’s Institutional fundings
Compliance with ethical standards
Conflict of interest
The authors declare no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
- 1.Alves CL, Elias D, Lyng M, Bak M, Kirkegaard T, Lykkesfeldt AE, Ditzel HJ (2016) High CDK6 protects cells from fulvestrant-mediated apoptosis and is a predictor of resistance to fulvestrant in estrogen receptor-positive metastatic breast cancer. Clin Cancer Res 22:5514–5526. https://doi.org/10.1158/1078-0432.CCR-15-1984 CrossRefPubMedGoogle Scholar
- 2.Bagegni N, Thomas S, Liu N, Luo J, Hoog J, Northfelt DW, Goetz MP, Forero A, Bergqvist M, Karen J, Neumuller M, Suh EM, Guo Z, Vij K, Sanati S, Ellis M, Ma CX (2017) Serum thymidine kinase 1 activity as a pharmacodynamic marker of cyclin-dependent kinase 4/6 inhibition in patients with early-stage breast cancer receiving neoadjuvant palbociclib. Breast Cancer Res 19:123. https://doi.org/10.1186/s13058-017-0913-7 CrossRefPubMedPubMedCentralGoogle Scholar
- 4.Bjohle J, Bergqvist J, Gronowitz JS, Johansson H, Carlsson L, Einbeigi Z, Linderholm B, Loman N, Malmberg M, Soderberg M, Sundquist M, Walz TM, Ferno M, Bergh J, Hatschek T (2013) Serum thymidine kinase activity compared with CA 15-3 in locally advanced and metastatic breast cancer within a randomized trial. Breast Cancer Res Treat 139:751–758. https://doi.org/10.1007/s10549-013-2579-x CrossRefPubMedGoogle Scholar
- 5.Chen P, Lee NV, Hu W, Xu M, Ferre RA, Lam H, Bergqvist S, Solowiej J, Diehl W, He YA, Yu X, Nagata A, VanArsdale T, Murray BW (2016) Spectrum and degree of CDK drug interactions predicts clinical performance. Mol Cancer Ther 15:2273–2281. https://doi.org/10.1158/1535-7163.MCT-16-0300 CrossRefPubMedGoogle Scholar
- 6.Condorelli R, Spring L, O’Shaughnessy J, Lacroix L, Bailleux C, Scott V, Dubois J, Nagy RJ, Lanman RB, Iafrate AJ, Andre F, Bardia A (2018) Polyclonal RB1 mutations and acquired resistance to CDK 4/6 inhibitors in patients with metastatic breast cancer. Ann Oncol 29:640–645. https://doi.org/10.1093/annonc/mdx784 CrossRefPubMedGoogle Scholar
- 7.de Falco G, Giordano A (1998) CDK9 (PITALRE): a multifunctional cdc2-related kinase. J Cell Physiol 177:501–506. https://doi.org/10.1002/(SICI)1097-4652(199812)177:4%3c501:AID-JCP1%3e3.0.CO;2-4 CrossRefPubMedGoogle Scholar
- 9.Finn RS, Crown JP, Lang I, Boer K, Bondarenko IM, Kulyk SO, Ettl J, Patel R, Pinter T, Schmidt M, Shparyk Y, Thummala AR, Voytko NL, Fowst C, Huang X, Kim ST, Randolph S, Slamon DJ (2015) The cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with letrozole versus letrozole alone as first-line treatment of oestrogen receptor-positive, HER2-negative, advanced breast cancer (PALOMA-1/TRIO-18): a randomised phase 2 study. Lancet Oncol 16:25–35. https://doi.org/10.1016/S1470-2045(14)71159-3 CrossRefPubMedGoogle Scholar
- 12.Herrera-Abreu MT, Palafox M, Asghar U, Rivas MA, Cutts RJ, Garcia-Murillas I, Pearson A, Guzman M, Rodriguez O, Grueso J, Bellet M, Cortes J, Elliott R, Pancholi S, Baselga J, Dowsett M, Martin LA, Turner NC, Serra V (2016) Early adaptation and acquired resistance to CDK4/6 inhibition in estrogen receptor-positive breast cancer. Cancer Res 76:2301–2313. https://doi.org/10.1158/0008-5472.CAN-15-0728 CrossRefPubMedPubMedCentralGoogle Scholar
- 14.Mazzanti CM, Lessi F, Armogida I, Zavaglia K, Franceschi S, Al Hamad M, Roncella M, Ghilli M, Boldrini A, Aretini P, Fanelli G, Marchetti I, Scatena C, Hochman J, Naccarato AG, Bevilacqua G (2015) Human saliva as route of inter-human infection for mouse mammary tumor virus. Oncotarget 6:18355–18363. https://doi.org/10.18632/oncotarget.4567 CrossRefPubMedPubMedCentralGoogle Scholar
- 16.Nisman B, Allweis T, Kadouri L, Mali B, Hamburger T, Baras M, Gronowitz S, Peretz T (2013) Comparison of diagnostic and prognostic performance of two assays measuring thymidine kinase 1 activity in serum of breast cancer patients. Clin Chem Lab Med 51:439–447. https://doi.org/10.1515/cclm-2012-0162 CrossRefPubMedGoogle Scholar
- 17.Schlafstein AJ, Withers AE, Rudra S, Danelia D, Switchenko JM, Mister D, Harari S, Zhang H, Daddacha W, Ehdaivand S, Li X, Torres MA, Yu DS (2018) CDK9 expression shows role as a potential prognostic biomarker in breast cancer patients who fail to achieve pathologic complete response after neoadjuvant chemotherapy. Int J Breast Cancer 2018:6945129. https://doi.org/10.1155/2018/6945129 CrossRefPubMedPubMedCentralGoogle Scholar
- 20.Vasan N, Yelensky R, Wang K, Moulder S, Dzimitrowicz H, Avritscher R, Wang B, Wu Y, Cronin MT, Palmer G, Symmans WF, Miller VA, Stephens P, Pusztai L (2014) A targeted next-generation sequencing assay detects a high frequency of therapeutically targetable alterations in primary and metastatic breast cancers: implications for clinical practice. Oncologist 19:453–458. https://doi.org/10.1634/theoncologist.2013-0377 CrossRefPubMedPubMedCentralGoogle Scholar