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CDK4/6 blockade provides an alternative approach for treatment of mismatch-repair deficient tumors
Mismatch repair-deficient (dMMR) tumors show a good response toward immune checkpoint inhibitors (ICI), but developing resistance impairs patients' outcomes. Here, we compared the therapeutic potential of an α-PD-L1 antibody with the CDK4/6 inhibitor abemaciclib in two preclinical mouse models...
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Published in: | Oncoimmunology 2022-12, Vol.11 (1), p.2094583-2094583 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Mismatch repair-deficient (dMMR) tumors show a good response toward immune checkpoint inhibitors (ICI), but developing resistance impairs patients' outcomes. Here, we compared the therapeutic potential of an α-PD-L1 antibody with the CDK4/6 inhibitor abemaciclib in two preclinical mouse models of dMMR cancer, focusing on immune-modulatory effects of either treatment. Abemaciclib monotherapy significantly prolonged overall survival of Mlh1
−/−
and Msh2
loxP/loxP;TgTg(Vil1-
cre)
mice (Mlh1
−/−
: 14.5 wks vs. 9.0 wks (α-PD-L1), and 3.5 wks (control); Msh2
loxP/loxP;TgTg(Vil1-
cre)
: 11.7 wks vs. 9.6 wks (α-PD-L1), and 2.0 wks (control)). The combination was not superior to either monotherapy. PET/CT imaging revealed individual response profiles, with best clinical responses seen with abemaciclib mono- and combination therapy. Therapeutic effects were accompanied by increasing numbers of tumor-infiltrating CD4
+
/CD8
+
T-cells and lower numbers of M2-macrophages. Levels of T cell exhaustion markers and regulatory T cell counts declined. Expression analysis identified higher numbers of dendritic cells and neutrophils within tumors together with high expression of DNA damage repair genes as part of the global stress response. In Mlh1
−/−
tumors, abemaciclib suppressed the PI3K/Akt pathway and led to induction of Mxd4/Myc. The immune-modulatory potential of abemaciclib renders this compound ideal for dMMR patients not eligible for ICI treatment. |
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ISSN: | 2162-402X 2162-4011 2162-402X |
DOI: | 10.1080/2162402X.2022.2094583 |