GPER1 links estrogens to centrosome amplification and chromosomal instability in human colon cells

Differences in the role of Gper1 in colorectal cancer progression depending on sex

To evaluate the role of 17β-oestradiol (E2) in the sex-dependent progression of colorectal cancer (CRC), the present study focused on E2 signalling mediated via the nuclear receptors [oestrogen receptor (ESR)1 and ESR2] and the membrane G protein-coupled oestrogen receptor 1 (Gper1) in males and females diagnosed with CRC. This study also investigated Gper1 signalling in the CRC cell lines DLD1 and LoVo, which differ in the p53 pathway. In cancer tissue, Gper1 becomes by far the most abundant E2 receptor due to an increase in Gper1 and a decrease in ESR2 expression. These changes are more prominent in males than in females. More pronounced differences in Gper1 expression between cancer and adjacent tissues were observed in males in lower stages compared with those in higher stages of disease and females. High expression of Gper1 was associated with worse survival in males without nodal involvement but not in females. The expression of E2 receptors in the CRC cell lines DLD1 and LoVo resembles that of human cancer tissue. Silencing of Gper1 (siGper1) caused an increase in the rate of metabolism in LoVo cells with wild-type tp53. In DLD1 cells with the mutated form of tp53, siGper1 did not exert this effect. High levels of Gper1 were associated with worse survival and could contribute to sex-dependent changes in the CRC prognosis. Tumour suppressor effects of Gper1 were, at least to some extent, dependent on signalling downstream of p53, which was more frequently deficient in males than in females. Overall, this suggests that up-regulation of Gper1 (or administration of a Gper1 agonist) would be more beneficial for patients with wild-type tp53.

Direct and indirect effects of estrogens, androgens and intestinal microbiota on colorectal cancer

Sex differences in colorectal cancer (CRC) has received considerable research attention recently, particularly regarding the influence of sex hormones and the intestinal microbiota. Estrogen, at the genetic and epigenetic levels, directly inhibits CRC cell proliferation by enhancing DNA mismatch repair, regulating miRNAs, blocking the cell cycle, and modulating ion channels. However, estradiol's activation of GPER promotes oncogene expression. Conversely, androgen contributes to epigenetic dysregulation and CRC progression via nuclear receptors while inducing apoptosis through membrane receptors. Specific gut microorganisms produce genotoxins and oncogenic metabolites that damage colonic cell DNA and contribute to cancer induction. Regarding the tumor microenvironment, estrogen mitigates intestinal inflammation, reverses immunosuppression, increases gut microbiome diversity and commensal bacteria abundance, and decreases pathogen enrichment. On the contrary, androgen disrupts intestinal microecology, diminish immunotherapy efficacy, and exacerbate colonic inflammation and tumor growth. The impact of estrogen and androgen is closely tied to their receptor status, elucidating their dual roles in CRC pathogenesis. This review comprehensively discusses the direct and indirect effects of sex hormones and the intestinal microbiota on CRC, considering environmental factors such as diet and lifestyle to propose novel prevention and treatment strategies.

17β-estradiol in colorectal cancer: friend or foe?

Colorectal cancer (CRC) is a common gastrointestinal malignancy with higher incidence and mortality rates in men compared to women, potentially due to the effects of estrogen signaling. There is substantial evidence supporting the significant role of 17β-Estradiol (E2) in reducing CRC risk in females, although this perspective remains debated. E2 has been demonstrated to inhibit CRC cell proliferation and migration at the cellular level by enhancing DNA mismatch repair, modulating key gene expression, triggering cell cycle arrest, and reducing activity of migration factors. Furthermore, E2 contributes to promote a tumor microenvironment unfavorable for CRC growth by stimulating ERβ expression, reducing inflammatory responses, reversing immunosuppression, and altering the gut microbiome composition. Conversely, under conditions of high oxidative stress, hypoxia, and nutritional deficiencies, E2 may facilitate CRC development through GPER-mediated non-genomic signaling. E2's influence on CRC involves the genomic and non-genomic signals mediated by ERβ and GPER, respectively, leading to its dual roles in anticancer activity and carcinogenesis. This review aims to summarize the potential mechanisms by which E2 directly or indirectly impacts CRC development, providing insights into the phenomenon of sexual dimorphism in CRC and suggesting potential strategies for prevention and treatment.

The two sides of chromosomal instability: drivers and brakes in cancer

Chromosomal instability (CIN) is a hallmark of cancer and is associated with tumor cell malignancy. CIN triggers a chain reaction in cells leading to chromosomal abnormalities, including deviations from the normal chromosome number or structural changes in chromosomes. CIN arises from errors in DNA replication and chromosome segregation during cell division, leading to the formation of cells with abnormal number and/or structure of chromosomes. Errors in DNA replication result from abnormal replication licensing as well as replication stress, such as double-strand breaks and stalled replication forks; meanwhile, errors in chromosome segregation stem from defects in chromosome segregation machinery, including centrosome amplification, erroneous microtubule-kinetochore attachments, spindle assembly checkpoint, or defective sister chromatids cohesion. In normal cells, CIN is deleterious and is associated with DNA damage, proteotoxic stress, metabolic alteration, cell cycle arrest, and senescence. Paradoxically, despite these negative consequences, CIN is one of the hallmarks of cancer found in over 90% of solid tumors and in blood cancers. Furthermore, CIN could endow tumors with enhanced adaptation capabilities due to increased intratumor heterogeneity, thereby facilitating adaptive resistance to therapies; however, excessive CIN could induce tumor cells death, leading to the "just-right" model for CIN in tumors. Elucidating the complex nature of CIN is crucial for understanding the dynamics of tumorigenesis and for developing effective anti-tumor treatments. This review provides an overview of causes and consequences of CIN, as well as the paradox of CIN, a phenomenon that continues to perplex researchers. Finally, this review explores the potential of CIN-based anti-tumor therapy.