No abstract

Doxycycline, an antibiotic, displays the inhibition of different signal transduction pathways, such as anti-inflammation and anti-proliferation, in different types of cancers. However, the anti-cancer mechanisms of doxycycline via integrin αvβ3 are incompletely understood. Integrin αvβ3 is a cell-surface anchor protein. It is the target for estrogen, androgen, and thyroid hormone and plays a pivotal role in the proliferation, migration, and angiogenic process in cancer cells. In our previous study, thyroxine hormones can interact with integrin αvβ3 to activate the extracellular signal-regulated kinase 1/2 (ERK1/2), and upregulate programmed death-ligand 1 (PD-L1) expression. In the current study, we investigated the inhibitory effects of doxycycline on proliferation in two breast cancer cell lines, MCF-7 and MDA-MB-231 cells. Doxycycline induces concentration-dependent anti-proliferation in both breast cancer cell lines. It regulates gene expressions involved in proliferation, pro-apoptosis, and angiogenesis. Doxycycline suppresses cell cyclin D1 (CCND1) and c-Myc which play crucial roles in proliferation. It also inhibits PD-L1 gene expression. Our findings show that modulation on integrin αvβ3 binding activities changed both thyroxine- and doxycycline-induced signal transductions by an integrin αvβ3 inhibitor (HSDVHK-NH2). Doxycycline activates phosphorylation of focal adhesion kinase (FAK), a downstream of integrin, but inhibits the ERK1/2 phosphorylation. Regardless, doxycycline-induced FAK phosphorylation is blocked by HSDVHK-NH2. In addition, the specific mechanism of action associated with pERK1/2 inhibition via integrin αvβ3 is unknown for doxycycline treatment. On the other hand, our findings indicated that inhibiting ERK1/2 activation leads to suppression of PD-L1 expression by doxycycline treatment. Furthermore, doxycycline-induced gene expressions are disturbed by a specific integrin αvβ3 inhibitor (HSDVHK-NH2) or a mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) kinase (MAPK/ERK, MEK) inhibitor (PD98059). The results imply that doxycycline may interact with integrin αvβ3 and inhibits ERK1/2 activation, thereby regulating cell proliferation and downregulating PD-L1 gene expression in estrogen receptor (ER)-negative breast cancer MDA-MB-231 cells.

Reduced fertility associated with normal aging may reflect the over-maturity of oocytes. It is increasingly important to reduce aging-induced infertility since recent trends show people marrying at later ages. 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG), a polyphenol extracted from Polygonum multiflorum, has been reported to have anti-inflammatory and anti-aging properties. To evaluate whether THSG can reduce aging-related ovarian damage in a female mouse model of aging, THSG was administered by gavage at a dose of 10 mg/kg twice weekly, starting at 4 weeks of age in a group of young mice. In addition, the effect of THSG in a group of aged mice was also studied in mice starting at 24 weeks of age. The number of oocytes in the THSG-fed group was higher than in the untreated control group. Although the percentage of secondary polar bodies (PB2) decreased during aging in the THSG-fed group, it decreased much more slowly than in the age-matched control group. THSG administration increased the quality of ovaries in young mice becoming aged. Western blotting analyses also indicated that CYP19, PR-B, and ER-β expressions were significantly increased in 36-week-old mice. THSG also increased oocyte numbers in aged mice compared to mice without THSG fed. Studies of qPCR and immunohistochemistry (IHC) analyses of ovaries in the aged mice groups were conducted. THSG increased gene expression of anti-Müllerian hormone (AMH), a biomarker of oocyte number, and protein accumulation in 40-week-old mice. THSG increased the expression of pgc1α and atp6, mitochondrial biogenesis-related genes, and their protein expression. THSG also attenuated the fading rate of CYP11a and CYP19 associated with sex hormone synthesis. And THSG maintains a high level of ER-β expression, thereby enhancing the sensitivity of estrogen. Our findings indicated that THSG increased or extended gene expression involved in ovarian maintenance and rejuvenation in young and aged mice. On the other hand, THSG treatments significantly maintained oocyte quantity and quality in both groups of young and aged mice compared to each age-matched control group. In conclusion, THSG can delay aging-related menopause, and the antioxidant properties of THSG may make it suitable for preventing aging-induced infertility.

Background: Progesterone (P4) stimulates reproductive functions such as ovulation and the initiation and maintenance of pregnancy. P4 regulates biological activities via its nuclear receptor. However, it is not fully understood mechanisms involved in P4 functions in PR-negative cells. Anchor protein integrin αvβ3 plays a vital role in cancer growth and metastasis. Methods: We investigated the effect of P4 in PR-positive breast cancer MCF-7 cells and PR-negative breast cancer MDA-MB-231 cells. The protein and RNA expression changes induced by P4 were both analyzed in two cell lines. At the same time, the anti-integrin αvβ3 antibody and RGD peptide were employed for investigating the role of integrin αvβ3 in P4 regulation. Results: P4 inhibited the proliferation in MCF-7 cells but stimulated cell growth in MDA-MB-231 cells. In addition to ERK1/2 activation, P4 stimulated the phosphorylation at Y397 and Y925 in focal adhesion kinase (FAK), a vital kinase in integrin ανβ3 signal pathway that modulated by co-treatment with anti-integrin αvβ3 antibody or RGD peptide. P4 activated the gene expression of integrin ανβ3, CCND1, PCNA, and MMP-9 in MDA-MB-231 cells. P4 also induced PD-L1 and CCND1 accumulation. Conclusions: Progesterone via integrin αvβ3-mediated signal transduction regulates gene expression, cell proliferation, and migration in TNBC cells. It is the first time to demonstrate that P4 binds with the cell surface anchor protein, integrin αvβ3, to stimulate cancer cell proliferation in PR-negative breast cancer cells. Keywords: Progesterone, Progesterone receptor, Integrin αvβ3, Breast cancer, Cell proliferation Citation Format: Hung-Yun Lin, Tung-Yung Huang, Tung-Cheng Chang, Han-Yu Chen, Haw-Ming Huang, Sheng-Yang Lee, Zi-Lin Li, Hung-Ru Chu, Jacqueline Whang-Peng, Kuan Wang. Progesterone via integrin αvβ3 induces cell proliferation in PR-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 114.