The Team of Profs. Zhaocai Zhou and Shi Jiao develops a new strategy for anti-tumor immunity by specifically targeting tumor-infiltrated Treg cells
Source：Zhaocai Zhou
2024-09-24
Regulatory T cells (Treg) play a crucial role in maintaining immune homeostasis. However, Treg establish an immunosuppressive tumor microenvironment (TME) for protecting tumor cells from immune surveillance, thereby facilitating tumor progression. Increased tumor-infiltrated (TI-Treg) cell number and reduced Teff/TI-Treg cell number ratio in the TME are associated with poor prognosis, resistance and tumor progression during immune checkpoint blockade therapy. Therefore, restraining TI-Treg cell activity or eliminating TI-Treg cells represents a potentially important strategy in tumor immunotherapy. Drugs targeting Treg are still in preclinical and clinical research stages and there are currently no small molecule compounds for clinical treatment targeting Treg. In addition, a major concern with targeting TI-Treg cells is the risk of autoimmunity, which can arise from systemic Treg cell depletion. Thus, how to selectively target TI-Treg cells without disrupting systemic immune homeostasis has always been a major challenge in this field.
Complexes of the evolutionarily conserved ATPases associated with diverse cellular activities (AAA+) superfamily ATPase p97 (Vcp), with various cofactors participate in a wide range of cellular processes including ubiquitinated protein degradation, DNA repair, homotypic membrane fusion, cell cycle regulation and autophagy. Npl4 is one of the important co-factors for p97, that p97 in complex with Npl4 can extract misfolded or polyubiquitinated proteins for subsequent degradation by the proteasome, a process important for quality control of soluble, membrane-associated, glycosylated proteins. Given its important function in protein homeostasis and cancer cell proliferation, p97 has been drawing great attention as an attractive drug target. Recently, multiple compounds targeting p97 that can induce apoptosis of cancer cells have under clinical research stages. However, side effects remain a challenging issue because these inhibitors all target the ATPase activity of p97 and thus would block a wide range of p97-mediated physiological processes including those yet to have been discovered in immune cells.
On August 6, 2024, Professor Zhaocai Zhou and Shi Jiao’s team from Fudan University published a research paper in Nature Immunology, entitled "Targeting p97–Npl4 interaction inhibits tumor Treg cell development to enhance tumor immunity". This research reveals that targeting the p97-Npl4 interaction specifically inhibit TI-Treg, thereby enhance the anti-tumor immunity and provide new strategy for tumor immunotherapy.
Previously, Professor Zhou’s team revealed the non-canonical function of the p97-Npl4 complex in regulating RIG-I mediated antiviral immune responses. Based on this work, they speculate that targeting the interface of the p97-Npl4 complex, but not targeting the activity of p97 ATPase, could develop new compound with stronger specificity and fewer toxic side effect. For this, they first performed a high-throughput AlphaScreen assay with 8,120 FDA-approved drugs and identified the compound Thonzoniumbromide (TB) that can disrupt the p97-Npl4 interaction. In vitro tumor cell proliferation and in vivo nude mouse tumorigenesis model both showed that TB had similar antitumor effects to CB-5083. By contrast, in a series of immunocompetent mouse tumor models, TB exhibited stronger antitumor activity than CB-5083, suggesting that TB might also regulate tumor immunity in vivo. Further single-cell sequencing analysis and T cell adoptive transfer assay clearly indicated that TB indeed reshaped tumor immune microenvironment and promoted the anti-tumor activity of CD8+ T cells.
To clarify the cell types through which TB targets the p97-Npl4 interaction to exert its tumor immunity regulatory function, they subsequently constructed conditional p973A mutant knock-in mice based on the previously resolved three-dimensional structural information of the p97-Npl4 complex. After introducing the p973A mutation into CD4+ T cells, however, they found no significant effect on tumor growth. Therefore, they conducted a detailed analysis of different T cell subsets and found that TB treatment significantly inhibited the number of tumor-infiltrated Treg cells while greatly promoting the number of Th17 cells. Furthermore, specifically introducing the p973A mutation into Treg cells significantly inhibited tumor growth, accompanied a marked decrease in TI-Treg numbers and an increase in Th17 cells. It is worth mentioning that targeting the p97-Npl4 complex specifically inhibited the TI-Treg but has no significant effect on peripheral Treg cells and the systemic immune homeostasis. Finally, the research team demonstrated the molecular mechanism by which the p97-Npl4 complex bridges Stat3 with E3 ligases PDLIM2 and PDLIM5, thereby promoting Stat3 degradation and regulating the balance of Treg-Th17 differentiation.
In summary, this study identified a function of the p97–Npl4 complex in regulating the balance of Treg-Th17 differentiation through the recruitment of E3 ubiquitin ligases PDLIM2/5 to promote the ubiquitination and degradation of Stat3. This study offers new avenues for the development of tumor immunotherapy strategies with stronger specificity and fewer toxic side effects.
Professor Zhaocai Zhou and Shi Jiao from the School of Life Sciences at Fudan University are the co-corresponding authors of this paper. Researchers from Fudan University, Tongji University, and the First Affiliated Hospital of Kunming Medical University collaborated on this project. Postdoctoral fellows Pingping Nie and Zhifa Cao, Ph.D student Ruixian Yu and Dr. Chao Dong also contribute equally to the paper. This work is supported by Professor Yufang Shi of Soochow University, Professor Bin Li of Shanghai Jiao Tong University, Dr. Xiaolong Liu and Dr. Yun Zhao of Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, and Dr. Ying Wang of the Institute of Nutrition and Health, Chinese Academy of Sciences. This project is funded by the National Key Research and Development Program of China, the National Natural Science Foundation of China's Original Exploration Program/Key Program/International (Regional) Cooperation Program/General Program and China Postdoctoral Science Foundation.
Article Link: https://www.nature.com/articles/s41590-024-01912-y
Complexes of the evolutionarily conserved ATPases associated with diverse cellular activities (AAA+) superfamily ATPase p97 (Vcp), with various cofactors participate in a wide range of cellular processes including ubiquitinated protein degradation, DNA repair, homotypic membrane fusion, cell cycle regulation and autophagy. Npl4 is one of the important co-factors for p97, that p97 in complex with Npl4 can extract misfolded or polyubiquitinated proteins for subsequent degradation by the proteasome, a process important for quality control of soluble, membrane-associated, glycosylated proteins. Given its important function in protein homeostasis and cancer cell proliferation, p97 has been drawing great attention as an attractive drug target. Recently, multiple compounds targeting p97 that can induce apoptosis of cancer cells have under clinical research stages. However, side effects remain a challenging issue because these inhibitors all target the ATPase activity of p97 and thus would block a wide range of p97-mediated physiological processes including those yet to have been discovered in immune cells.
On August 6, 2024, Professor Zhaocai Zhou and Shi Jiao’s team from Fudan University published a research paper in Nature Immunology, entitled "Targeting p97–Npl4 interaction inhibits tumor Treg cell development to enhance tumor immunity". This research reveals that targeting the p97-Npl4 interaction specifically inhibit TI-Treg, thereby enhance the anti-tumor immunity and provide new strategy for tumor immunotherapy.
Previously, Professor Zhou’s team revealed the non-canonical function of the p97-Npl4 complex in regulating RIG-I mediated antiviral immune responses. Based on this work, they speculate that targeting the interface of the p97-Npl4 complex, but not targeting the activity of p97 ATPase, could develop new compound with stronger specificity and fewer toxic side effect. For this, they first performed a high-throughput AlphaScreen assay with 8,120 FDA-approved drugs and identified the compound Thonzoniumbromide (TB) that can disrupt the p97-Npl4 interaction. In vitro tumor cell proliferation and in vivo nude mouse tumorigenesis model both showed that TB had similar antitumor effects to CB-5083. By contrast, in a series of immunocompetent mouse tumor models, TB exhibited stronger antitumor activity than CB-5083, suggesting that TB might also regulate tumor immunity in vivo. Further single-cell sequencing analysis and T cell adoptive transfer assay clearly indicated that TB indeed reshaped tumor immune microenvironment and promoted the anti-tumor activity of CD8+ T cells.
To clarify the cell types through which TB targets the p97-Npl4 interaction to exert its tumor immunity regulatory function, they subsequently constructed conditional p973A mutant knock-in mice based on the previously resolved three-dimensional structural information of the p97-Npl4 complex. After introducing the p973A mutation into CD4+ T cells, however, they found no significant effect on tumor growth. Therefore, they conducted a detailed analysis of different T cell subsets and found that TB treatment significantly inhibited the number of tumor-infiltrated Treg cells while greatly promoting the number of Th17 cells. Furthermore, specifically introducing the p973A mutation into Treg cells significantly inhibited tumor growth, accompanied a marked decrease in TI-Treg numbers and an increase in Th17 cells. It is worth mentioning that targeting the p97-Npl4 complex specifically inhibited the TI-Treg but has no significant effect on peripheral Treg cells and the systemic immune homeostasis. Finally, the research team demonstrated the molecular mechanism by which the p97-Npl4 complex bridges Stat3 with E3 ligases PDLIM2 and PDLIM5, thereby promoting Stat3 degradation and regulating the balance of Treg-Th17 differentiation.
In summary, this study identified a function of the p97–Npl4 complex in regulating the balance of Treg-Th17 differentiation through the recruitment of E3 ubiquitin ligases PDLIM2/5 to promote the ubiquitination and degradation of Stat3. This study offers new avenues for the development of tumor immunotherapy strategies with stronger specificity and fewer toxic side effects.
Professor Zhaocai Zhou and Shi Jiao from the School of Life Sciences at Fudan University are the co-corresponding authors of this paper. Researchers from Fudan University, Tongji University, and the First Affiliated Hospital of Kunming Medical University collaborated on this project. Postdoctoral fellows Pingping Nie and Zhifa Cao, Ph.D student Ruixian Yu and Dr. Chao Dong also contribute equally to the paper. This work is supported by Professor Yufang Shi of Soochow University, Professor Bin Li of Shanghai Jiao Tong University, Dr. Xiaolong Liu and Dr. Yun Zhao of Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, and Dr. Ying Wang of the Institute of Nutrition and Health, Chinese Academy of Sciences. This project is funded by the National Key Research and Development Program of China, the National Natural Science Foundation of China's Original Exploration Program/Key Program/International (Regional) Cooperation Program/General Program and China Postdoctoral Science Foundation.
Article Link: https://www.nature.com/articles/s41590-024-01912-y
