{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T10:16:51Z","timestamp":1788257811357,"version":"build-2803163510"},"reference-count":35,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006606","name":"Natural Science Foundation of Tianjin, China","doi-asserted-by":"publisher","award":["23JCZDJC00840"],"award-info":[{"award-number":["23JCZDJC00840"]}],"id":[{"id":"10.13039\/501100006606","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Interleukin-12 (IL-12) potently promotes the recruitment and activation of immune cells within the tumor microenvironment (TME), highlighting its immense potential for cancer therapy. However, its dose-limiting systemic toxicity and short half-life severely hinder its clinical translation. Here, we design a tumor-conditionally activated IL-12 prodrug termed \u03b1HSA-proIL-12. This engineered molecule integrates a cleavable albumin-binding nanobody (\u03b1HSA) domain to extend the half-life and enhance tumor targeting alongside a masking domain that occludes the IL-12 receptor-binding site to prevent nonspecific activation. This construct undergoes selective cleavage by matrix metalloproteinases (MMPs) that are highly expressed in the TME to release highly penetrant, free, low-molecular-weight IL-12 locally. This tumor-restricted activation process directly facilitates the selective recruitment and activation of tumor-infiltrating lymphocytes (TILs). The intravenous administration of an extremely low dose of 108 pmol per dose of \u03b1HSA-proIL-12 completely cleared MC38 tumors without inducing systemic toxicity. The maximum tolerated dose of this molecule exceeded 2 nmol, yielding a remarkably wide therapeutic index &gt;18.5. Mechanistically, \u03b1HSA-proIL-12 effectively reprogrammed the immunosuppressive TME by expanding the numbers of effector CD8+ T cells and natural killer cells while upregulating IFN-\u03b3 expression and significantly reducing the proportion of regulatory T cells. This immunological remodeling has the potential to convert \u201ccold\u201d tumors into \u201chot\u201d tumors. Notably, this treatment achieved complete regression and durable immunity in a subset of mice with multiple refractory immune-cold tumors, including Panc02 pancreatic cancer, 4T1 triple-negative breast cancer, and B16F10 melanoma, when administered as a monotherapy or in combination with PD-L1 blockade. Furthermore, when combined with surgery, \u03b1HSA-proIL-12 effectively prevented the postoperative recurrence and distant metastasis of advanced 4T1 tumors. This modular platform provides a clinically promising strategy to overcome the toxicity bottleneck of cytokines and substantially advances the development of combination cancer immunotherapies.<\/jats:p>","DOI":"10.3390\/ijms27177716","type":"journal-article","created":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T09:48:36Z","timestamp":1788256116000},"page":"7716","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["\u03b1HSA-proIL-12: A Tumor-Conditional IL-12 Prodrug with Reduced Systemic Toxicity and Potent Antitumor Activity"],"prefix":"10.3390","volume":"27","author":[{"given":"Xi","family":"Wang","sequence":"first","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Liu","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Yuhao","family":"Hou","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Guanyu","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Yu","family":"Ding","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"given":"Yu","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"given":"Shuyu","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0086-4541","authenticated-orcid":false,"given":"Zhangyong","family":"Hong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China"},{"name":"Nankai International Advanced Research Institute (ShenzhenFutian), Shenzhen 518045, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1148","DOI":"10.1016\/j.immuni.2018.09.024","article-title":"Successful anti-PD-1 cancer immunotherapy requires T cell-dendritic cell crosstalk involving the cytokines IFN-\u03b3 and IL-12","volume":"49","author":"Garris","year":"2018","journal-title":"Immunity"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1007\/s00262-014-1523-1","article-title":"Interleukin 12: Still a promising candidate for tumor immunotherapy?","volume":"63","author":"Lasek","year":"2014","journal-title":"Cancer Immunol. 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