HMN 2025: How CDK4/6 inhibitor mixture may overcome drug resistance in superior prostate cancer

With an estimated 1.5 million new instances and 397,000 deaths worldwide, prostate cancer is the world’s second most frequent cancer and the fifth main reason for cancer demise amongst males in 2022. Hormone remedy based mostly on the inhibition of androgen receptor signaling (ARPi) is the mainstay of remedy for metastatic prostate cancer (mPC). However, cancer drug resistance finally arises, highlighting the necessity for more practical therapeutic methods.

Aimed at overcoming drug resistance in prostate cancer remedy, considered one of VHIO’s Prostate Cancer Group key targets is to advance insights into the genomic panorama and biology underpinning prostate cancer to reveal novel vulnerabilities in tumor cells, develop new therapies, and optimize current ones.

Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors represent a promising therapeutic avenue for various tumor sorts, a few of which have already been permitted for the remedy of superior estrogen receptor (ER)-positive breast cancer. Despite promising leads to preclinical models of mPC, significantly in research combining them with different therapies, a number of scientific trials of CDK4/6i, as monotherapy or together, have generated adverse outcomes.

An revolutionary preclinical study led by Joaquin Mateo was designed to handle the problem of drug resistance related to CDK4/6i in mPC from a brand new perspective. Instead of focusing solely on the direct results of those medication, they delved deeper into the modifications in tumor cells induced by CDK4/6 inhibitors and thus sought to establish new therapeutic vulnerabilities.

An revolutionary sequential strategy

Published in Molecular Cancer Therapeutics, the outcomes of this study present that following remedy with CDK4/6 inhibitors, a small subset of persistent tumor cells enter a hibernation-like state, referred to as “dormancy,” to evade remedy. These dormant cancer cells can sadly “get up” years later, inflicting tumor relapse. The investigators confirmed that the mix of those inhibitors with senolytic therapies may forestall illness recurrence.

“In a spread of in vitro and in vivo prostate cancer models, together with patient-derived xenografts, our preclinical investigations present that CDK4/6 inhibitors halt the expansion of prostate cancer cells and induce a senescent state, that may be focused utilizing senolytic therapies,” mentioned Joaquin Mateo, a Medical Oncologist on the Vall d’Hebron University Hospital, co-leader of VHIO’s Prostate Cancer Group, and corresponding creator of this study.

The researchers additionally reported that residual tumor cells present elevated sensitivity to PARPi, a kind of focused cancer drug already permitted for the remedy of prostate cancer. This statement opens the door to designing new sequential remedy methods that mix each therapies to enhance scientific outcomes.

Notably, in a second part of their preclinical investigations, this sequential technique additionally capitalizes on a second biological impact of CDK4/6 inhibitors on tumor cells, observing that when publicity to those medication cease abruptly, tumor cells quickly accumulate DNA harm.

“This impact opens a window of alternative for remedy with PARP inhibitors. Upfront mixed inhibition with CDK4/6 and PARP1 has no antitumor impact. However, their sequential use including PARPi upon CDK4/6i withdrawal leads to hanging antitumor exercise,” noticed Julian Brandariz, a Ph.D. Student of VHIO’s Prostate Cancer Group and first creator of this work.

“Our outcomes reveal the potential of CDK4/6i in prostate cancer remedy, significantly when adopted by sequential remedy with senolytic remedy or PARPi. This new one-two punch technique holds promise in overcoming cancer drug resistance, enhancing remedy outcomes for metastatic prostate cancer, and open avenues for repurposing CDK4/6i remedy in metastatic prostate cancer,” concluded Mateo.

These findings symbolize a step ahead in personalizing and optimizing remedy for superior prostate cancer and will present new scientific rationale for the design of future scientific trials.