Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by limited treatment options and unfavorable clinical outcomes. Therefore, the research described in this thesis... Show moreTriple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by limited treatment options and unfavorable clinical outcomes. Therefore, the research described in this thesis focused on the exploration of novel targeted therapies for TNBC. Through high-throughput screening, we assessed the responsiveness of TNBC cells to kinase inhibitors, which indicated a notable sensitivity to cyclin-dependent kinase (CDK) inhibitors. Building upon these findings, this thesis systematically compares the efficacy of targeting various transcription-associated CDKs, with CDK9 and CDK12 emerging as highly potent targets for disrupting TNBC cell proliferation. Transcription-associated CDKs play multiple roles in regulating mRNA transcription. Yet, inhibitors of these CDK’s induced selective, rather than global, changes in gene expression. This provides insights into their mechanisms of action and suggesting potential opportunities for combination therapy. Furthermore, our research elucidated the mechanism underlying the synergistic effects of combining kinase inhibitors with transcriptional CDK inhibitors, by demonstrating that this is mediated through the inhibition of cellular drug efflux by ABCG2. In conclusion, this thesis highlights the potential of transcription-associated CDK inhibitors as a promising avenue for treating TNBC. The insights from this thesis will help to further steer the (pre)clinical development and strategy of using transcription-associated CDK inhibitors for the treatment of TNBC. Show less
