Facilitated By

San Antonio Medical Foundation

(PQ3) NOVEL TUMOR INTRINSIC PD-L1 SIGNALS DIRECT TUMOR IMMUNE CELL INFILTRATION

UT Health San Antonio

The UT Health San Antonio, with missions of teaching, research and healing, is one of the country’s leading health sciences universities.

Principal Investigator(s)
Curiel, Tyler J
Collaborating Institutions
DARTMONTH
Funded by
NIH-NATIONAL CANCER INSTITUTE
Research Start Date
Status
Active

We respond to PQ3 with our data showing that tumor PD-L1 (CD274, B7-H1) is a major regulator of tumorinflammatory infiltrates. Our preliminary data show that melanoma PD-L1 regulates TIL through severalpreviously unknown tumor-intrinsic and extrinsic mechanisms. We define novel effects of tumor intrinsic PD-L1signaling on tumor proliferation, sensitivity to immune killing, in vivo growth independent of anti-tumorimmunity, and regulation of mTOR signals. We identified intracellular PD-L1, including those whose surfaceexpression is low or negative, and identified interactions with tumor PD-1. We hypothesize that melanomaintrinsic PD-L1-driven signals, particularly mTOR signals, alter tumor progression and treatmentresponses. The research team is comprised of tumor immunotherapy, tumor immunology and PD-L1 expertsat UTHSCSA and Dartmouth. We focus on melanoma for scientific reasons and based on our expertise.Aim 1 Define how tumor PD-L1 alters tumor immune infiltrates and immunotherapy responses. We usecontrol versus PD-L1lo (shRNA) B16 in a novel model to study differential treatment outcomes by tumor PD-L1status. We generated PD-L1KO B16 by CRISPR for highly detailed follow up mechanistic studies, and to assessif PD-L1 null status differentially affects treatment versus PD-L1lo. Effects will also be tested in transplantedBrafV600E mutated D4M melanoma (PD-L1+) engineered to be PD-L1lo and PD-L1KO, in mice with inducedBrafV600E melanomas, and in syngeneic skin grafts of skin from Braf/Pten versus PD-L1KO Braf/Pten mice.Aim 2 Test tumor PD-L1-driven mTOR signal effects on TIL and immunotherapy responses. We will testPD-L1 KO, PD-1 KO and double KO melanoma cells for mTOR signals, TIL and treatment effects. Cells will beengineered for defects in mTORC1/2 for mechanistic studies, complemented with mTOR inhibitor treatments.We will use engineered tumors that express cytoplasm-only versus cell surface-only PD-L1, to define novel,intracellular PD-L1 signals. Constructs with mutations in known PD-1 signal sites will be engineered into thesetumors for a complete understanding of PD-L1/PD-1 interactions.Aim 3 Define cell-intrinsic PD-L1 effects in human melanoma. We use well-defined human melanoma linesthat are basal PD-L1+ and/or PD-1+ and/or BrafV600E mutated. We will use human vectors to knock down orknock out PD-L1, PD-1 and mTORC1/2 genes. In vitro assessments of effects on proliferation, responses tomTOR inhibitors, ?PD-L1 and ?PD-1 will be assessed. In vivo effects in NSG mice will be assessed. Primaryhuman melanoma lines will be studied to complement data from long-term lines.

Collaborative Project
Clinical Care
Cancer