Abstract 3354: Cancer-associated or cirrhosis fibroblasts recovered from hepatocellular carcinoma promote macrophages and cancer cells to progressive phenotype
Authors: Mano Yohei , Kanto Tatsuya , Shoji Hirotaka , Yoshio Schiyo , Sugiyama Masaya , Osawa Yosuke , Kimura Kiminori , Shirabe Ken , Maehara Yoshihiko , Mizokami Masashi 
Published: August 2015

Background/Aim: Tumor microenvironment plays supportive roles for cancer cells of proliferating, invading and spreading systemically. Cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs) are deemed to be essential constituents forming cancer-surrounding niche. However, the cross-talks between CAFs and TAMs in the settings of hepatocellular carcinoma (HCC) has yet to be deciphered. The lack of a reliable system simulating in vivo-microenvironment has been one of the obstacles hampering investigation of CAFs and TAMs. By using the newly-established model consisting of fibroblasts directly recovered from the disease liver, we aimed to clarify the mechanisms of CAFs modulating the macrophage differentiation and malignant potential of cancer cells in order to search for therapeutic targets.

Methods: We enrolled three patients who underwent the resection of HCC and two who did living donor liver transplantation. From the resected or the explanted livers, fibroblasts from cancer and its adjacent tissues were separated by tissue digestion. We examined their ontogeny by the expression of fibroblast-specific markers. For the functional analyses, we examined invasiveness of HuH7 cells on matrigel and migratory response of monocytes in the presence of conditioned media (CM) from the fibroblasts. We assessed the phenotypes/function of macrophages after the differentiation from monocytes in the presence of M-CSF and the CM. We comprehensively assayed cytokine/chemokine in the CM to identify functionally-relevant factors.

Results): After the culture, we established three types of fibroblasts, CAFs, cirrhotic liver fibroblasts (LCFs) and non-cancerous fibroblasts (NFs). All of these were positive for vimentin, SMA, PDGFRa and FAP (&gt;99%), confirming that they are ontologically fibroblasts instead of being HCC, hepatocytes or biliary cells. The invasiveness of HuH7 were higher in the presence of the CAF- or LCF-CM compared to those with NF-CM. Similar superiority was observed with the CAF- or LCF-CM in the migratory ability of monocytes. In the process of macrophage differentiation, the CAF- or LCF-CM were capable of polarizing macrophages into TAM/M2 subtypes, as evidenced by their higher production of IL-10 but lesser IL-12. In the CAF- or LCM-CM, the levels of IL6, IL-8, CCL2 and GRO were higher than those in the NF-CM.

Conclusion: The CAFs as well as LCFs directly recovered from the cirrhotic liver are functionally competent of driving TAM/M2 differentiation and providing malignant potential to cancer cells, thereby tuning the microenvironment favoring HCC development.

Citation Format: Yohei Mano, Tatsuya Kanto, Hirotaka Shoji, Schiyo Yoshio, Masaya Sugiyama, Yosuke Osawa, Kiminori Kimura, Ken Shirabe, Yoshihiko Maehara, Masashi Mizokami. Cancer-associated or cirrhosis fibroblasts recovered from hepatocellular carcinoma promote macrophages and cancer cells to progressive phenotype. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3354. doi:10.1158/1538-7445.AM2015-3354