Insuline-Like Growth Factor-2 (IGF2) and Hepatocyte Growth Factor (HGF) Promote Lymphomagenesis in p53-null Mice in Tissue-specific and Estrogen-signaling Dependent Manners

Hsuan-Shun Huang; Sung-Chao Chu; Pao-Chu Chen; Ming-Hsun Lee; Chi-Ya Huang; Hsien-Ming Chou; Tang-Yuan Chu

doi:10.7150/jca.60120

Insuline-Like Growth Factor-2 (IGF2) and Hepatocyte Growth Factor (HGF) Promote Lymphomagenesis in p53-null Mice in Tissue-specific and Estrogen-signaling Dependent Manners

J Cancer. 2021 Aug 21;12(20):6021-6030. doi: 10.7150/jca.60120. eCollection 2021.

Authors

Hsuan-Shun Huang¹, Sung-Chao Chu^{2

3}, Pao-Chu Chen⁴, Ming-Hsun Lee⁵, Chi-Ya Huang¹, Hsien-Ming Chou¹, Tang-Yuan Chu^{1

4

6}

Affiliations

¹ Center for Prevention and Therapy of Gynecological Cancers, Department of Research, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan, ROC.
² Department of Hematology and Oncology, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan, ROC.
³ School of Medicine, College of Medicine, Tzu Chi University, Hualien 970, Taiwan, ROC.
⁴ Department of Obstetrics & Gynecology, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan, ROC.
⁵ Department of Pathology, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan, ROC.
⁶ Department of Life Science, Tzu Chi University, Hualien 970, Taiwan, ROC.

Abstract

Background: Trp53^-/- mice are prone to develop lymphomas at old ages. Factors promoting this tumorigenesis are unknown. Here, we showed human ovulatory follicular fluid (FF) largely promotes lymphomagenesis in Trp53^-/- mice at earlier ages. Meanwhile, we clarified that IGF2 and HGF are important cell transforming factors within FF. Methods: To induce tumor formation, 5% FFs, 100 ng/ml IGF2, 20 ng/ml HGF, or both IGF2 and HGF in a volume of 200 µl PBS, was injected into 8-wk-old female Trp53 ^-/- mice at the mammary fat pad. The injection was repeated weekly for up to 7 weeks or extending to 13 weeks to observe the accumulative incidence of lymphomagenesis. Immunohistochemistry staining and gene rearrangement analysis were used to identify the tumor type. Results: By injecting FF into the mammary fat pad weekly, lymphomas developed in 8/16 (50%) of mice by seven weeks. We identified IGF2 and HGF in FF is largely responsible for this activity. The same weekly injection of IGF2, HGF, and their combination induced lymphomas in 4/11 (36%), 3/8 (38%), and 6/9 (67%) mice, respectively. Interestingly, tumorigenesis was induced only when those were injected into the adipose tissues in the mammary gland, but not when injected into non-adipose sites. We also found this tumor-promoting activity is estradiol (E2)-dependent and relies on estrogen receptor (ER) α expression in the adipose stroma. No tumor or only tiny tumor was yielded when the ovaries were resected or when ER is antagonized. Finally, an extension of the weekly FF-injection to 13 weeks did not further increase the lymphomagenesis rate, suggesting an effect on pre-initiated cancer cells. Conclusions: Taken together, the study disclosed a robust tumor-promoting effect of IGF2 and HGF in the p53 loss-initiated lymphomagenesis depending on an adipose microenvironment in the presence of E2. In light of the clarity of this spontaneous tumor promotion model, we provide a new tool for studying p53-mediated lymphomagenesis and suggest that, as a chemoprevention test, this is a practical model to perform.

Keywords: IGF; Trp53; estrogen; follicular fluids; lymphoma.