Benign tumors in TSC are amenable to treatment by GD3 CAR T cells in mice
Ancy Thomas, … , Richard P. Junghans, I. Caroline Le Poole
Ancy Thomas, … , Richard P. Junghans, I. Caroline Le Poole
Published November 22, 2021
Citation Information: JCI Insight. 2021;6(22):e152014. https://doi.org/10.1172/jci.insight.152014.
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Research Article Immunology Therapeutics

Benign tumors in TSC are amenable to treatment by GD3 CAR T cells in mice

Abstract

Mutations underlying disease in tuberous sclerosis complex (TSC) give rise to tumors with biallelic mutations in TSC1 or TSC2 and hyperactive mammalian target of rapamycin complex 1 (mTORC1). Benign tumors might exhibit de novo expression of immunogens, targetable by immunotherapy. As tumors may rely on ganglioside D3 (GD3) expression for mTORC1 activation and growth, we compared GD3 expression in tissues from patients with TSC and controls. GD3 was overexpressed in affected tissues from patients with TSC and also in aging Tsc2+/– mice. As GD3 overexpression was not accompanied by marked natural immune responses to the target molecule, we performed preclinical studies with GD3 chimeric antigen receptor (CAR) T cells. Polyfunctional CAR T cells were cytotoxic toward GD3-overexpressing targets. In mice challenged with Tsc2–/– tumor cells, CAR T cells substantially and durably reduced the tumor burden, correlating with increased T cell infiltration. We also treated aged Tsc2+/– heterozygous (>60 weeks) mice that carry spontaneous Tsc2–/– tumors with GD3 CAR or untransduced T cells and evaluated them at endpoint. Following CAR T cell treatment, the majority of mice were tumor free while all control animals carried tumors. The outcomes demonstrate a strong treatment effect and suggest that targeting GD3 can be successful in TSC.

Authors

Ancy Thomas, Saurav Sumughan, Emilia R. Dellacecca, Rohan S. Shivde, Nicola Lancki, Zhussipbek Mukhatayev, Cristina C. Vaca, Fei Han, Levi Barse, Steven W. Henning, Jesus Zamora-Pineda, Suhail Akhtar, Nikhilesh Gupta, Jasmine O. Zahid, Stephanie R. Zack, Prathyaya Ramesh, Dinesh Jaishankar, Agnes S.Y. Lo, Joel Moss, Maria M. Picken, Thomas N. Darling, Denise M. Scholtens, Daniel F. Dilling, Richard P. Junghans, I. Caroline Le Poole

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Figure 5

GD3 CAR T cells target Tsc2–/– tumors in immunodeficient SCID/Bg mice.

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GD3 CAR T cells target Tsc2–/– tumors in immunodeficient SCID/Bg mice. (...
(A) Surface GD3 expression by LB1 Tsc2–/– kidney tumor cells used for subcutaneous tumor injections, and B16-F10 mouse melanoma cells for comparison with a shift of 545 in MFI for LB1 and a shift of 298 for B16-F10, representing a 2.7- and 3.6-fold increase in fluorescence over background for LB1 cells and B16 cells, respectively. (B) Tumor volumes in the treatment groups over time. Figure shows data from a representative experiment of 2 performed. Each group had 6 animals, and tumor volumes were documented every other day for 22 days after the first T cell treatment. Statistical analysis was carried out using R software, and splines were fit using the splines2 package. Two-sided P values are provided using a Bonferroni correction, with P values of P = 3.3 × 10–6 for the comparison of CAR T cells with PBS and P = 3.2 × 10–15 for the comparison of GD3 CAR T cells with the untransduced T cell group. (C) Quantification of CD3+ T cells infiltrating subcutaneous tumors after adoptive T cell transfer in SCID/Bg mice that received untransduced or GD3 CAR T cells, n = 3. *P = 0.022. A 2-tailed Student’s t test assuming equal variance was used to compare groups. Bar graphs show mean values ± SD.