TY - JOUR
T1 - Targeted therapy given after anti⇓PD-1 leads to prolonged responses in mouse melanoma models through sustained antitumor immunity
AU - Phadke, Manali S.
AU - Chen, Zhihua
AU - Li, Jiannong
AU - Mohamed, Eslam
AU - Davies, Michael A.
AU - Smalley, Inna
AU - Duckett, Derek R.
AU - Palve, Vinayak
AU - Czerniecki, Brian J.
AU - Forsyth, Peter A.
AU - Noyes, David
AU - Adeegbe, Dennis O.
AU - Eroglu, Zeynep
AU - Nguyen, Kimberly T.
AU - Tsai, Kenneth Y.
AU - Rix, Uwe
AU - Burd, Christin E.
AU - Chen, Yian A.
AU - Rodriguez, Paulo C.
AU - Smalley, Keiran S.M.
N1 - Publisher Copyright:
2021 American Association for Cancer Research.
PY - 2021/5/1
Y1 - 2021/5/1
N2 - Immunotherapy (IT) and targeted therapy (TT) are both effective against melanoma, but their combination is frequently toxic. Here, we investigated whether the sequence of IT (anti–PD-1)! TT (ceritinib–trametinib or dabrafenib–trametinib) was associated with improved antitumor responses in mouse models of BRAF- and NRAS-mutant melanoma. Mice with NRAS-mutant (SW1) or BRAF-mutant (SM1) mouse melanomas were treated with either IT, TT, or the sequence of IT!TT. Tumor volumes were measured, and samples from the NRAS-mutant melanomas were collected for immune-cell analysis, single-cell RNA sequencing (scRNA-seq), and reverse phase protein analysis (RPPA). scRNA-seq demonstrated that the IT!TT sequence modulated the immune environment, leading to increased infiltration of T cells, monocytes, dendritic cells and natural killer cells, and decreased numbers of tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells. Durable responses to the IT!TT sequence were dependent on T-cell activity, with depletion of CD8þ, but not CD4þ, T cells abrogating the therapeutic response. An analysis of transcriptional heterogeneity in the melanoma compartment showed the sequence of IT!TT enriched for a population of melanoma cells with increased expression of MHC class I and melanoma antigens. RPPA analysis demonstrated that the sustained immune response induced by IT!TT suppressed tumor-intrinsic signaling pathways required for therapeutic escape. These studies establish that upfront IT improves the responses to TT in BRAF- and NRAS-mutant melanoma models.
AB - Immunotherapy (IT) and targeted therapy (TT) are both effective against melanoma, but their combination is frequently toxic. Here, we investigated whether the sequence of IT (anti–PD-1)! TT (ceritinib–trametinib or dabrafenib–trametinib) was associated with improved antitumor responses in mouse models of BRAF- and NRAS-mutant melanoma. Mice with NRAS-mutant (SW1) or BRAF-mutant (SM1) mouse melanomas were treated with either IT, TT, or the sequence of IT!TT. Tumor volumes were measured, and samples from the NRAS-mutant melanomas were collected for immune-cell analysis, single-cell RNA sequencing (scRNA-seq), and reverse phase protein analysis (RPPA). scRNA-seq demonstrated that the IT!TT sequence modulated the immune environment, leading to increased infiltration of T cells, monocytes, dendritic cells and natural killer cells, and decreased numbers of tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells. Durable responses to the IT!TT sequence were dependent on T-cell activity, with depletion of CD8þ, but not CD4þ, T cells abrogating the therapeutic response. An analysis of transcriptional heterogeneity in the melanoma compartment showed the sequence of IT!TT enriched for a population of melanoma cells with increased expression of MHC class I and melanoma antigens. RPPA analysis demonstrated that the sustained immune response induced by IT!TT suppressed tumor-intrinsic signaling pathways required for therapeutic escape. These studies establish that upfront IT improves the responses to TT in BRAF- and NRAS-mutant melanoma models.
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U2 - 10.1158/2326-6066.CIR-20-0905
DO - 10.1158/2326-6066.CIR-20-0905
M3 - Article
C2 - 33653716
AN - SCOPUS:85105268554
SN - 2326-6066
VL - 9
SP - 554
EP - 567
JO - Cancer Immunology Research
JF - Cancer Immunology Research
IS - 5
ER -