Knockdown of IGF-binding protein 7 inhibits transformation of the endometrial gland in an in vitro model

The multifaceted role of insulin-like growth factor binding protein 7

Insulin-like growth factor binding protein 7 (IGFBP7) serves as a crucial extracellular matrix protein, exerting pivotal roles in both physiological and pathological processes. This comprehensive review meticulously delineates the structural attributes of IGFBP7, juxtaposing them with other members within the IGFBP families, and delves into the expression patterns across various tissues. Furthermore, the review thoroughly examines the multifaceted functions of IGFBP7, encompassing its regulatory effects on cell proliferation, apoptosis, and migration, elucidating the underlying mechanistic pathways. Moreover, it underscores the compelling roles in tumor progression, acute kidney injury, and reproductive processes. By rigorously elucidating the diverse functionalities and regulatory networks of IGFBP7 across various physiological and pathological contexts, this review aims to furnish a robust theoretical framework and delineate future research trajectories for leveraging IGFBP7 in disease diagnosis, therapeutic interventions, and pharmaceutical innovations.

Comparative Proteomic Analysis Reveals Metformin Improves the Expression of Biomarkers of Endometrial Receptivity in Infertile Women with Minimal/Mild Endometriosis

The prevalence of endometriosis is approximately 10% in women of reproductive age, and 30-50% of women with endometriosis are infertile. Metformin has been reported to inhibit the growth of ectopic lesions in endometriosis. However, its effect on the eutopic endometrium of endometriosis is unknown. This study aimed to identify whether metformin affects endometrial receptivity in infertile women with minimal/mild endometriosis. We enrolled 10 infertile women who were diagnosed with minimal/mild endometriosis through laparoscopy. Paired endometrial tissues of the secretory phase from participants were collected during surgery and after 2 months of metformin treatment (n = 5) or no medical treatment (n = 5). Protein expression profiles of the paired endometrium were detected by proteomics and compared using the self-control method (2 months later vs. in surgery). Proteomics data revealed six proteins associated with endometrial receptivity among the significantly upregulated proteins after metformin treatment (fold change > 1.5, P < 0.05). Insulin-like growth factor binding protein 7 (IGFBP-7) showed the most robust increase in these six endometrial receptivity-related proteins (fold change: 8.668, P < 0.05), while there was no significant change in the controls (fold change: 1.906, P > 0.05). The upregulation of IGFBP-7 has been validated through target proteomics, immunohistochemistry, and further demonstrated in endometriosis mouse models induced by autotransplantation. This study revealed that metformin upregulated the expression of IGFBP-7 in the endometrium of human and mouse models of endometriosis. Metformin potentially affects endometrial receptivity of minimal/mild endometriosis by improving the expression of the endometrial receptivity marker IGFBP-7.

Comprehensive Analysis of IGFBPs as Biomarkers in Gastric Cancer

OBJECTIVE

Gastric cancer is the fifth most common cancer worldwide and the third leading cause of cancer-related deaths. Insulin-like growth-factor-binding proteins (IGFBPs) were initially identified as passive inhibitors that combined with insulin-like growth factors (IGFs) in serum. However, more recent data have shown that they have different expression patterns and a variety of functions in the development and occurrence of cancers. Thus, their various roles in cancer still need to be elucidated. This study aimed to explore the IGFBPs and their prognostic value as markers in gastric cancer.

METHODS

Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, and TIMER were used to analyze the differential expression, prognostic value, genetic alteration, and association with immune cell infiltration of IGFPBs in gastric cancer.

RESULTS

Expression levels of IGFBP3, IGFBP4, and IGFBP7 were significantly elevated in gastric cancer tissues, whereas those of IGFBP1 were reduced in normal tissues. IGFBP1/5/7 expression was significantly associated with overall survival whereas IGFBP6/7 expression was significantly correlated with disease-free survival in gastric cancer patients. IGFBP3/5/6/7 were associated with clinical cancer stage. Gene ontology and Kyoto Encyclopedia of Genes and Genome analyses showed that IGFBP3/5/7 were mainly enriched in focal adhesion, extracellular matrix structural constituent, cell-substratist junction, extracellular structure, and matrix organization. Stomach adenocarcinoma (STAD) and gastric cancer had more IGFBP1-7 mutations than other tumor types. Hub gene analysis showed that TP53 and IGF2 expression was significantly elevated in STAD patients; PLG, PAPPA, AFP, and CYR61 were associated with overall survival rate; and IGFALS, PLG, IGF1, AHSG, and FN1 were associated with disease-free survival. Finally, IGFBP3-7 were all associated with cancer-associated fibroblast infiltration in STAD, colon adenocarcinoma, and rectal adenocarcinoma.

CONCLUSION

Our study provides a comprehensive analysis and selection of IGFBPs as prognostic biomarkers in STAD. This was the first bioinformatic analysis study to describe the involvement of IGFBPs, especially IGFBP7, in gastric cancer development through the extracellular matrix.

A Proteome Approach Reveals Differences between Fertile Women and Patients with Repeated Implantation Failure on Endometrial Level⁻Does hCG Render the Endometrium of RIF Patients?

Background: The molecular signature of endometrial receptivity still remains barely understood, especially when focused on the possible benefit of therapeutical interventions and implantation-related pathologies. Therefore, the protein composition of tissue and isolated primary cells (endometrial stromal cells, ESCs) from endometrial scratchings of ART (Assisted Reproductive Techniques) patients with repeated implantation failure (RIF) was compared to volunteers with proven fertility during the time of embryo implantation (LH + 7). Furthermore, an analysis of the endometrial tissue of fertile women infused with human chorionic gonadotropin (hCG) was conducted. Methods: Endometrial samples (n = 6 RIF, n = 10 fertile controls) were split into 3 pieces: 1/3 each was frozen in liquid nitrogen, 1/3 fixed in PFA and 1/3 cultured. Protein lysates prepared from fresh frozen tissue were processed for mass spectrometric analysis. Results: Three proteins (EPPK1, BCLAF1 and PTMA) showed a statistically altered abundance in the endometrial tissue of RIF patients. Furthermore, pathways like metabolism, immune system, ferroptosis and the endoplasmic reticulum were altered in RIF patients. Remarkably, endometrial tissues of RIF patients showed a significantly higher (p-value = 9 × 10⁻⁸) protein intensity correlation (Pearson’s correlation coefficient = 0.95) compared to fertile women (Pearson’s correlation coefficient = 0.88). The in vivo infusion of hCG stimulated proteins of endocytosis, HIF1 signalling and chemokine production. Notably, patients suffering from RIF had a clinical pregnancy rate of 19% after the intrauterine infusion of hCG before embryo transfer (ET) compared to their failed previous cycles. Conclusion: Our study showed for the first time that the endometrial proteome composition of RIF patients differs from fertile controls during the window of implantation. The intrauterine infusion of hCG prior to an embryo transfer might improve the chemokine triggered embryo-endometrial dialogue and intensify the angiogenesis and immune response. From a clinical point of view, the hCG infusion prior to an embryo transfer might increase the pregnancy rate of RIF patients.

Expression of IGFBP7 mRNA in corticotrophs in the anterior pituitary of adrenalectomized rats

The number of corticotrophs increases in the anterior pituitary (AP) gland in adrenalectomized (AdX) rats. In this study, aimed at identifying the growth factor implicated in this proliferation, we analyzed proteins secreted from a cDNA library of the AP of AdX rats, using the signal sequence trap method. A PCR analysis of several cDNAs that coded for insulin-like growth factor binding protein (IGFBP) 5, IGFBP7, and vacuolar H+-ATPase accessory subunit Ac45 revealed an increased and decreased expression level of IGFBP7 mRNA in the AP of AdX rats and AdX rats injected with dexamethasone, respectively. IGFBP7 mRNA was predominately expressed in the corticotrophs of the APs of both sham-operated and AdX rats. The AP of AdX rats contained an increased number of IGFBP7 mRNA-expressing cells and corticotrophs compared with that of sham-operated rats, but the ratio of IGFBP7 mRNA-positive corticotrophs per total number of corticotrophs did not significantly change in either group. Histochemical analysis of labeled proliferating cell nuclear antigen (PCNA) and sex-determining region Y box-2 (SOX2) revealed the presence of several PCNA-positive signals and the absence of SOX2 cells among the corticotrophs, suggesting that IGFBP7 mRNA-expressing corticotrophs are derived from in situ corticotrophs and that they increase in number as corticotrophs increase. The possible roles of IGFBP7 in the corticotrophs are also discussed.