Scholarlink

Background <p>Targeting components of the tumor microenvironment has become a pan-cancer treatment strategy. Fibroblast activation protein (FAP)-targeted radioligand therapy exploits FAP expression in cancer-associated fibroblasts (CAFs) within the tumor stroma. However, several preclinical models use cancer cell lines engineered to overexpress FAP, which poorly reflects the clinical scenario and may overestimate therapeutic efficacy. This study established a 3D co-culture spheroid model combining FAP-positive fibroblasts with FAP-negative prostate cancer cells to evaluate the therapeutic potential of [<sup>212</sup>Pb]Pb-FAPI-46.</p> Results <p>[<sup>212</sup>Pb]Pb-FAPI-46 was radiolabeled with &gt; 97% radiochemical purity and remained radiochemically stable for up to 48&#xa0;h in PBS, serum, and culture medium. Immortalized CAFs (PF179T) and immortalized normal fibroblasts (F11‑hTERT) exhibited high levels of FAP expression along with specific radioligand binding and uptake, while prostate cancer cells (22Rv1) demonstrated negligible FAP expression and radioligand binding. Co-culture spheroids formed compact 3D structures, with fibroblasts in the core and cancer cells at the periphery. Treatment significantly delayed spheroid growth compared to controls, with sensitivity increasing with fibroblast content. 22Rv1/F11-hTERT spheroids showed greater growth delay than 22Rv1/PF179T. Monoculture cancer spheroids lacking FAP expression were unaffected.</p> Conclusion <p>A 3D co-culture spheroid model with fibroblast-restricted FAP expression was established and used to evaluate the effect of [<sup>212</sup>Pb]Pb-FAPI-46. Although fibroblasts were non-proliferative in 3D monoculture, co-culture spheroids formed consistently and exhibited steady growth over time. Radioligand treatment induced a significant growth delay in co-culture spheroids compared to untreated controls, whereas FAP-negative tumor monoculture spheroids were unaffected. These results indicate that the observed growth inhibition arises from indirect effects mediated by targeted fibroblasts within the 3D architecture rather than from direct irradiation of tumor cells. Overall, this work demonstrates that FAP-targeted alpha therapy can exert measurable effects in 3D co-culture and provides an in vitro platform for evaluating stromal-targeted radionuclide therapies for cancers.</p> Graphical abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

A 3D co-culture model with fibroblast-restricted FAP expression for cancer therapy using [212Pb]Pb-FAPI-46

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年4月18日

查看全文
  • Sandra K. Kristiansen,
  • Nurtene Dernjani,
  • Øyvind S. Bruland,
  • Nina Frederike J. Edin,
  • Asta Juzeniene

摘要

Background

Targeting components of the tumor microenvironment has become a pan-cancer treatment strategy. Fibroblast activation protein (FAP)-targeted radioligand therapy exploits FAP expression in cancer-associated fibroblasts (CAFs) within the tumor stroma. However, several preclinical models use cancer cell lines engineered to overexpress FAP, which poorly reflects the clinical scenario and may overestimate therapeutic efficacy. This study established a 3D co-culture spheroid model combining FAP-positive fibroblasts with FAP-negative prostate cancer cells to evaluate the therapeutic potential of [212Pb]Pb-FAPI-46.

Results

[212Pb]Pb-FAPI-46 was radiolabeled with > 97% radiochemical purity and remained radiochemically stable for up to 48 h in PBS, serum, and culture medium. Immortalized CAFs (PF179T) and immortalized normal fibroblasts (F11‑hTERT) exhibited high levels of FAP expression along with specific radioligand binding and uptake, while prostate cancer cells (22Rv1) demonstrated negligible FAP expression and radioligand binding. Co-culture spheroids formed compact 3D structures, with fibroblasts in the core and cancer cells at the periphery. Treatment significantly delayed spheroid growth compared to controls, with sensitivity increasing with fibroblast content. 22Rv1/F11-hTERT spheroids showed greater growth delay than 22Rv1/PF179T. Monoculture cancer spheroids lacking FAP expression were unaffected.

Conclusion

A 3D co-culture spheroid model with fibroblast-restricted FAP expression was established and used to evaluate the effect of [212Pb]Pb-FAPI-46. Although fibroblasts were non-proliferative in 3D monoculture, co-culture spheroids formed consistently and exhibited steady growth over time. Radioligand treatment induced a significant growth delay in co-culture spheroids compared to untreated controls, whereas FAP-negative tumor monoculture spheroids were unaffected. These results indicate that the observed growth inhibition arises from indirect effects mediated by targeted fibroblasts within the 3D architecture rather than from direct irradiation of tumor cells. Overall, this work demonstrates that FAP-targeted alpha therapy can exert measurable effects in 3D co-culture and provides an in vitro platform for evaluating stromal-targeted radionuclide therapies for cancers.

Graphical abstract