Huidi Liu

Enterolactone and trabectedin suppress epithelial ovarian cancer synergistically via upregulating THBS1

AbstractEpithelial ovarian cancer (EOC) is the most common and fatal subtype of ovarian malignancies, with no effective therapeutics available. Our previous studies have demonstrated extraordinary suppressive efficacy of enterolactone (ENL) on EOC. A chemotherapeutic agent, trabectedin (Trabe), is shown to be effective on ovarian cancer, especially when combined with other therapeutics, such as pegylated liposomal doxorubicin or oxaliplatin. Thrombospondin 1 (THBS1), a kind of matrix glycoprotein, plays important roles against cancer development through inhibiting angiogenesis but whether it is involved in the suppression of EOC by ENL or Trabe remains unknown. To test combined suppressive effects of ENL and Trabe on EOC and possible involvement of THBS1 in the anticancer activities of ENL and Trabe. The EOC cell line ES‐2 was transfected with overexpressed THBS1 by lentivirus vector. We employed tube formation assay to evaluate the anti‐angiogenesis activity of ENL and of its combined use with Trabe after THBS1 overexpression and established drug intervention and xenograft nude mouse cancer models to assess the in vivo effects of the hypothesized synergistic suppression between the agents and the involvement of THBS1. Mouse fecal samples were collected for 16S rDNA sequencing and microbiota analysis. We detected strong inhibitory activities of ENL and Trabe against the proliferation and migration of cancer cells and observed synergistic effects between ENL and Trabe in suppressing EOC. ENL and Trabe, given either separately or in combination, could suppress the tube formation capability of human microvascular endothelial cells, and this inhibitory effect became even stronger with THBS1 overexpression. In the ENL plus Trabe combination group, the expression of tissue inhibitor of metalloproteinases 3 and cluster of differentiation 36 was both upregulated, whereas matrix metalloproteinase 9, vascular endothelial growth factor, and cluster of differentiation 47 were all decreased. With the overexpression of THBS1, the results became even more pronounced. In animal experiments, combined use of ENL and Trabe showed superior inhibitory effects to either single agent and significantly suppressed tumor growth, and the overexpression of THBS1 further enhanced the anti‐cancer activities of the drug combination group. ENL and Trabe synergistically suppress EOC and THBS1 could remarkably facilitate the synergistic anticancer effects of ENL and Trabe.

Enterolactone combined with m6A Reader IGF2BP3 inhibits malignant angiogenesis and disease progression in ovarian cancer

Among all gynecological cancers, ovarian cancer is the leading cause of death. Epithelial ovarian cancer (EOC) accounts for over 85 % of ovarian cancer cases and is characterized by insidious onset, early metastasis, and a high recurrence rate. Alterations in gut microbiota, often as a consequence of chemotherapy, can promote cancer development and exacerbate the disease. The m6A reader IGF2BP3 is a regulator in the occurrence and progression of various tumors and is associated with angiogenesis. Enterolactone (ENL) has demonstrated significant anti-tumor activity against various human cancers, including EOC. However, whether ENL could interact with IGF2BP3 to suppress EOC remains unclear. This study aims to investigate suppressive effects of ENL upon combining with IGF2BP3 on EOC and elucidates the underlying mechanism. The Cell Counting Kit-8 and crystal violet assays were used to assess tumor cell proliferation. Scratch and Transwell assays were employed to evaluate tumor cell migration, while tube formation assays were utilized to examine angiogenesis. Western blotting was used to measure the expression levels of IGF2BP3, VEGF, PI3K, AKT1, p-PI3K, and p-AKT1. An in vivo xenograft nude mouse model was established, fecal samples were collected, and 16S rDNA sequencing was performed to analyze gut microbiota in association with the suppressive effects of ENL and its interactions with IGF2BP3. IGF2BP3 is highly expressed in EOC and is positively correlated with poor survival in EOC patients. ENL reduces IGF2BP3 expression in EOC, thereby inhibiting the IGF2BP3-mediated VEGF/PI3K/AKT signaling pathway and suppressing the proliferation, migration, invasion, and angiogenesis of EOC. Additionally, ENL ameliorates gut microbiome, especially in conjunction with shIGF2BP3. ENL interacts with IGF2BP3 and suppresses its expression in EOC, leading to the deactivation of the IGF2BP3-mediated VEGF/PI3K/AKT signaling pathway and the subsequent inhibition of angiogenesis. The combination of ENL and shIGF2BP3 demonstrates a synergistic effect on EOC. ENL also ameliorates the gut microbiome, especially in conjunction with shIGF2BP3, to suppress EOC.