Inhibition of lung tumorigenesis by a small molecule CA170 targeting the immune checkpoint protein VISTA

Jing Pan, Yao Chen, Qi Zhang, Achia Khatun, Katie Palen, Gang Xin, Li Wang, Chuanjia Yang, Bryon D. Johnson, Charles R. Myers, Shizuko Sei, Robert H. Shoemaker, Ronald A. Lubet, Yian Wang, Weiguo Cui, Ming You

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Expressed on cells of the myeloid and lymphoid lineages, V-domain Ig Suppressor of T cell Activation (VISTA) is an emerging target for cancer immunotherapy. Blocking VISTA activates both innate and adaptive immunity to eradicate tumors in mice. Using a tripeptide small molecule antagonist of VISTA CA170, we found that it exhibited potent anticancer efficacy on carcinogen-induced mouse lung tumorigenesis. Remarkably, lung tumor development was almost completely suppressed when CA170 was combined with an MHCII-directed KRAS peptide vaccine. Flow cytometry and single-cell RNA sequencing (scRNA-seq) revealed that CA170 increased CD8+ T cell infiltration and enhanced their effector functions by decreasing the tumor infiltration of myeloid-derived suppressor cells (MDSCs) and Regulatory T (Treg) cells, while the Kras vaccine primarily induced expansion of CD4+ effector T cells. VISTA antagonism by CA170 revealed strong efficacy against lung tumorigenesis with broad immunoregulatory functions that influence effector, memory and regulatory T cells, and drives an adaptive T cell tumor-specific immune response that enhances the efficacy of the KRAS vaccine.

Original languageEnglish (US)
Article number906
JournalCommunications Biology
Issue number1
StatePublished - Dec 2021

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)


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