Regional delivery of mesothelin-targeted chimeric antigen receptor T-cell effectively and safely targets colorectal cancer liver metastases in mice

Our plain-English summary of Regional delivery of mesothelin-targeted chimeric antigen receptor T-cell effectively and safely targets colorectal cancer liver metastases in mice, by X. Zhou, M. Yang, J. Yu, et al (Journal of Gastrointestinal Oncology, 2024).

The study

• Authors: X. Zhou, M. Yang, J. Yu, J. Tan, N. Xu, Y. Zhou, W. Zhang, J. Ma, Z. Zhang, A. Friedlaender, J. Taylor, L. Yu, Z. Yan
• Journal: Journal of Gastrointestinal Oncology
• Published: 2024;15(1):312-329
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Liver metastasis is the major cause of colorectal cancer related death. Mesothelin (MSLN)-targeted chimeric antigen receptor (CAR) T-cell therapy has been illustrated effective and safe through regional delivery of breast cancer, ovarian cancer and malignant mesothelioma tumors. Herein, we investigated the safety, efficacy, and immune microenvironment of regional delivery of MSLN (CAR) T-cell in the treatment of colorectal carcinoma liver metastases (CRLM).

Methods: Second-generation MSLN CAR T-cells were administered by portal vein (PV) or caudal vein (CV, systemic administration) delivery in an orthotopic MSLN+ CRLM nonobese diabetic (NOD)/severe combined immunodeficient (SCID)/γc-/- (NSG) mouse model. A total of 20 mice were randomly divided into control group, non-transduced T cell (NT)-CV group, NT-PV group, MSLN CAR T-cell CV (MSLN-CV) group, and MSLN CAR T-cell PV (MSLN-PV) group, with each group containing four mice to examine the safety and efficacy. The bioluminescence intensity (BLI) of tumor burden, tumor tissue macroscopic and microscopic observation were used to evaluate treatment efficacy. The safety was examined by body weight, survival time, and vital organ damage of mice. CAR T-cell infiltration and cytokine concentration were analyzed by flow cytometry, and immunostaining. The change of immune microenvironment between regional delivery and systemic delivery was investigated on an immune reconstructed CRLM patient-derived xenograft (PDX) model. Additionally, T cell subsets and immunosuppressive markers were examined.

Results: PV administration of 1×107/100 μL MSLN CAR T-cells in 20 NSG mice was well tolerated, and no overt toxicity was observed. The tumor burden in the PV group was obviously alleviated. The BLI was (0.73±0.52)×109 in PV group and (1.97±0.11)×109 in CV group (P<0.05), CD8+ granzyme B (GB)+ T cell percentage (MSLN-CV 4.42%±0.47% vs. MSLN-PV 13.5%±4.67%, P<0.01) and cytokine concentration were obviously increased in the MSLN-PV group. In the immune reconstituted CRLM PDX model, intratumor (IT) delivery of MSLN CAR T-cells exhibited much more infiltration of CD4+ and CD8+ T cells accompanied with elevated expression levels of PD-1, LAG-3, and TIM-3.

Conclusions: Regional delivery of MSLN-targeted CAR T-cell therapy has encouraging results in the orthotopic CRLM NSG mouse model and PDX model, and converts the tumor microenvironment from cold to hot. This study may provide a new therapeutic approach for CRLM. Further clinical study is needed.

2024 Journal of Gastrointestinal Oncology. All rights reserved.

In plain English

This was a laboratory and mouse study of second-generation, fully human mesothelin (MSLN)-targeted chimeric antigen receptor (CAR) T-cells for colorectal carcinoma liver metastases (CRLM). In cell culture, transduction efficiency of MSLN CAR T-cells ranged from 15% to 24.9%, and the cells killed MSLN-positive HGC-27 and HCT-8 cells but had nearly no killing effect on K562, Raji, ASPC-1 and BXPC-3 cells. Twenty NSG mice bearing orthotopic MSLN-positive CRLM were randomised into five groups of four: a control group, and four treatment groups given a single dose of 1x10(7) non-transduced or MSLN CAR T-cells in 100 microlitres by caudal or portal vein. Portal vein delivery was reported as well tolerated with no overt toxicity, with lower tumour bioluminescence than caudal vein delivery and greater MSLN+CD3+ and CD8+granzyme B+ T-cell infiltration. In a nine-mouse immune-reconstituted patient-derived xenograft model, intratumoral delivery gave the smallest tumours but the highest levels of PD-1, LAG-3 and TIM-3. The authors concluded regional delivery may offer a new therapeutic approach needing further clinical study.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Preclinical animal and in vitro experimental study (orthotopic NSG mouse model plus immune-reconstituted patient-derived xenograft model)
• Who was studied: 20 female NSG mice (6-8 weeks old) bearing orthotopic MSLN-positive CRLM from H-MSLN-Luc-HCT-8 cells, in 5 groups of 4; plus 9 NSG mice of a second-generation subcutaneous CRLM patient-derived xenograft with human immune reconstitution, in 3 groups; human tumour cell lines in vitro; Shanghai, China
• Exposure: A single dose of 1x10(7) fully human second-generation MSLN CAR T-cells (anti-MSLN scFv, CD8alpha hinge/transmembrane, 4-1BB, CD3 zeta) or non-transduced T cells in 100 microlitres saline, given by portal vein, caudal (systemic) vein, or intratumoral injection
• Main results:
  • In vitro, MSLN CAR T-cell transduction efficiency was 15% to 24.9%
  • In vitro killing was seen against MSLN-positive HGC-27 (printed HCG-27) and HCT-8 cells, but nearly none against K562, Raji, ASPC-1 and BXPC-3
  • Tumour bioluminescence reported in the article's printed abstract was (0.73±0.52)x10(9) in the portal vein group versus (1.97±0.11)x10(9) in the caudal vein group (P<0.05)
  • Mice in the control, NT-CV and NT-PV groups did not have tumour growth controlled and died on day 14
  • In the MSLN-PV group the tumour bioluminescence signal fell by day 7 and CRLM disappeared in two mice by day 21
  • MSLN+CD3+ T cells in tumour tissue were significantly higher in the portal vein group than the caudal vein group (P<0.001)
  • CD8+granzyme B+ T cells in tumour tissue were increased in the MSLN-PV group compared with MSLN-CV on day 14 (P<0.01)
  • Peripheral blood cytokines IL-2, IL-6, IFN-gamma and IL-17A were higher in the portal vein group than the caudal vein group
  • In the PDX model on day 21, tumour volume was 119.66±66.1 mm3 in the intratumoral group and 294.29±75.64 mm3 in the caudal vein group
  • In the PDX model, tumour volume in the control group was 921.26±273.02 mm3
  • In PDX tumour tissue, CD4+ and CD8+ T cells were significantly higher with intratumoral than caudal vein delivery, with no obvious difference in regulatory T cells between the three groups
  • Immunosuppressive markers LAG-3, TIM-3 and PD-1 increased in all three PDX groups at week 3, highest in the intratumoral group
  • Safety in the orthotopic model was judged by body weight, fur condition and HE staining of heart, kidney, lung and pancreas, with no obvious toxicities reported for the portal vein route
  • Median MSLN expression in the CRLM specimens was 56.3% (9/16) positive
• The authors' conclusion: The authors concluded that regional delivery of MSLN-targeted CAR T-cell therapy gave encouraging results in the orthotopic CRLM NSG mouse model and the PDX model, converted the tumour microenvironment from cold to hot, may provide a new therapeutic approach for CRLM, and that further clinical study is needed
• Limitations the authors state:
  • The authors state the observation time of the model was limited, so the later trend of the immunosuppressive changes is not clear
  • A subcutaneous rather than intrahepatic PDX model had to be used because of the long construction period, low survival of NSG mice after laparotomy, harsh feeding conditions and monitoring difficulties
  • The PDX experiment was terminated early because of the huPBMC model limit, weight loss over 30% or graft-versus-host effect
  • The authors note hepatic artery delivery was not used because of difficulties of artery puncture in NSG mice and feeding difficulties in large immunodeficient animals

Topics

Medical terms in this study, explained in our Lexicon: Mesothelin, Colorectal Cancer, Metastasis, Ovarian Cancer, Mesothelioma, Carcinoma, Tumor Burden, Cytokine.

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