Normalized Kynurenine Concentrate Over Time

Normalized Tryptophan Concentrate Over Time

Representativeness of study participants.

Palbociclib does not induce DNA damage in senescent LS8817 cells

Dose reductions in this study identified by individual patients

Abemaciclib induced changes in CD8+ TILs in individual patients

Effect of shRNA hairpins on geroconversion when introduced into quiescent DDLStetONFDM2 cells

Relationship between CDH18 expression, MDM2 downregulation, and ANGPTL4 mRNA expression in patients treated with abemaciclib

ANGPTL4 is the most widely expressed and highly enriched transcript in treated cells compared to untreated cells

Quantification of the Abemaciclib induced changes in CD4+ TILs in each patient

Quantification of the Abemaciclib induced changes in CDKN2A expression in each patient

Sequences of primers and shRNAs used in this study

Metabolome profiles of LS8817tetONFMDM2 undergoing cell cycle exit and geroconversion

Enforced expression of ANGPTL4 can induce stable growth arrest and SASP gene expression in A549 cells treated with palbociclib

Common SASP profile transcripts used in this study

Increases in ANGPTL4 are not associated with palbociclib induced senescence in ER+ breast cancer cell lines

Abemaciclib induced changes in FOXP3+ TILs in individual patients

ANGPTL4 is necessary to drive senescence in palbociclib treated A549 cells

AbstractPurpose: We conducted research on CDK4/6 inhibitors (CDK4/6i) simultaneously in the preclinical and clinical spaces to gain a deeper understanding of how senescence influences tumor growth in humans. Patients and Methods: We coordinated a first-in-kind phase II clinical trial of the CDK4/6i abemaciclib for patients with progressive dedifferentiated liposarcoma (DDLS) with cellular studies interrogating the molecular basis of geroconversion. Results: Thirty patients with progressing DDLS enrolled and were treated with 200 mg of abemaciclib twice daily. The median progression-free survival was 33 weeks at the time of the data lock, with 23 of 30 progression-free at 12 weeks (76.7%, two-sided 95% CI, 57.7%–90.1%). No new safety signals were identified. Concurrent preclinical work in liposarcoma cell lines identified ANGPTL4 as a necessary late regulator of geroconversion, the pathway from reversible cell-cycle exit to a stably arrested inflammation-provoking senescent cell. Using this insight, we were able to identify patients in which abemaciclib induced tumor cell senescence. Senescence correlated with increased leukocyte infiltration, primarily CD4-positive cells, within a month of therapy. However, those individuals with both senescence and increased TILs were also more likely to acquire resistance later in therapy. These suggest that combining senolytics with abemaciclib in a subset of patients may improve the duration of response. Conclusions: Abemaciclib was well tolerated and showed promising activity in DDLS. The discovery of ANGPTL4 as a late regulator of geroconversion helped to define how CDK4/6i-induced cellular senescence modulates the immune tumor microenvironment and contributes to both positive and negative clinical outcomes. See related commentary by Weiss et al., p. 649

Transcript changes relative to quiescence