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Inhibition of the Rho/MRTF pathway improves the response of BRAF-resistant melanoma to PD1/PDL1 blockade.
- Source :
-
International journal of cancer [Int J Cancer] 2024 Oct 01; Vol. 155 (7), pp. 1303-1315. Date of Electronic Publication: 2024 Jun 19. - Publication Year :
- 2024
-
Abstract
- Metastatic cutaneous melanoma is a fatal skin cancer. Resistance to targeted and immune therapies limits the benefits of current treatments. Identifying and adding anti-resistance agents to current treatment protocols can potentially improve clinical responses. Myocardin-related transcription factor (MRTF) is a transcriptional coactivator whose activity is indirectly regulated by actin and the Rho family of GTPases. We previously demonstrated that development of BRAF inhibitor (BRAFi) resistance frequently activates the Rho/MRTF pathway in human and mouse BRAF <superscript>V600E</superscript> melanomas. In clinical trials, pretreatment with BRAFi reduces the benefit of immune therapies. We aimed to test the efficacy of concurrent treatment with our MRTF pathway inhibitor CCG-257081 and anti-PD1 in vivo and to examine its effects on the melanoma immune microenvironment. Because MRTF pathway activation upregulates the expression of immune checkpoint inhibitor genes/proteins, we asked whether CCG-257081 can improve the response to immune checkpoint blockade. CCG-257081 reduced the expression of PDL1 in BRAFi-resistant melanoma cells and decreased surface PDL1 levels on both BRAFi-sensitive and -resistant melanoma cells. Using our recently described murine vemurafenib-resistant melanoma model, we found that CCG-257081, in combination with anti-PD1 immune therapy, reduced tumor growth and increased survival. Moreover, anti-PD1/CCG-257081 co-treatment increased infiltration of CD8 <superscript>+</superscript> T cells and B cells into the tumor microenvironment and reduced tumor-associated macrophages. Here, we propose CCG-257081 as an anti-resistance and immune therapy-enhancing anti-melanoma agent.<br /> (© 2024 The Author(s). International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)
- Subjects :
- Animals
Mice
Humans
Cell Line, Tumor
Programmed Cell Death 1 Receptor antagonists & inhibitors
Programmed Cell Death 1 Receptor metabolism
Trans-Activators metabolism
Trans-Activators genetics
Female
Signal Transduction drug effects
rho GTP-Binding Proteins metabolism
Proto-Oncogene Proteins B-raf antagonists & inhibitors
Proto-Oncogene Proteins B-raf genetics
Proto-Oncogene Proteins B-raf metabolism
Melanoma drug therapy
Melanoma metabolism
Melanoma genetics
Melanoma pathology
Drug Resistance, Neoplasm
B7-H1 Antigen antagonists & inhibitors
B7-H1 Antigen metabolism
Immune Checkpoint Inhibitors pharmacology
Immune Checkpoint Inhibitors therapeutic use
Skin Neoplasms drug therapy
Skin Neoplasms pathology
Skin Neoplasms genetics
Skin Neoplasms metabolism
Tumor Microenvironment drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1097-0215
- Volume :
- 155
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- International journal of cancer
- Publication Type :
- Academic Journal
- Accession number :
- 38898604
- Full Text :
- https://doi.org/10.1002/ijc.35056