BRCA1 185delAG Mutation Enhances Interleukin-1β Expression in Ovarian Surface Epithelial Cells

Pyroptosis and inflammasomes in cancer and inflammation

Nonprogrammed cell death (NPCD) and programmed cell death (PCD) are two types of cell death. Cell death is significantly linked to tumor development, medication resistance, cancer recurrence, and metastatic dissemination. Therefore, a comprehensive understanding of cell death is essential for the treatment of cancer. Pyroptosis is a kind of PCD distinct from autophagy and apoptosis in terms of the structure and function of cells. The defining features of pyroptosis include the release of an inflammatory cascade reaction and the expulsion of lysosomes, inflammatory mediators, and other cellular substances from within the cell. Additionally, it displays variations in osmotic pressure both within and outside the cell. Pyroptosis, as evidenced by a growing body of research, is critical for controlling the development of inflammatory diseases and cancer. In this paper, we reviewed the current level of knowledge on the mechanism of pyroptosis and inflammasomes and their connection to cancer and inflammatory diseases. This article presents a theoretical framework for investigating the potential of therapeutic targets in cancer and inflammatory diseases, overcoming medication resistance, establishing nanomedicines associated with pyroptosis, and developing risk prediction models in refractory cancer. Given the link between pyroptosis and the emergence of cancer and inflammatory diseases, pyroptosis-targeted treatments may be a cutting-edge treatment strategy.

The role of the inflammasome and its related pathways in ovarian cancer

Ovarian cancer (OC) is the most lethal tumor of the female reproductive tract and one of the most prevalent causes of death among female cancer patients. The absence of suitable procedures for early diagnosis, chemoresistance, and limited surgical debulking are all contributing to poor survival in patients. Despite aggressive treatments, the majority of patients have a recurrence within 16-22 months. Inflammasomes are multimeric protein complexes that play a major role in the innate immune system and inflammation. The overexpression of inflammasome-related pathways, including NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), Absent in melanoma 2 (AIM2), caspase-1, and Interleukin (IL)-1 have been reported in OC patients and in vitro cell lines. Therefore, inflammasome-related genes and protein might have a role in OC pathogenesis. Considering the potential relationship between inflammasome and OC, this study aimed to provide a literature-based review to explain the role of inflammasome and inflammation in cancer progression in OC.

Interleukin-1β and Cancer

Within a tumor, IL-1β is produced and secreted by various cell types, such as immune cells, fibroblasts, or cancer cells. The IL1B gene is induced after "priming" of the cells and a second signal is required to allow IL-1β maturation by inflammasome-activated caspase-1. IL-1β is then released and leads to transcription of target genes through its ligation with IL-1R1 on target cells. IL-1β expression and maturation are guided by gene polymorphisms and by the cellular context. In cancer, IL-1β has pleiotropic effects on immune cells, angiogenesis, cancer cell proliferation, migration, and metastasis. Moreover, anti-cancer treatments are able to promote IL-1β production by cancer or immune cells, with opposite effects on cancer progression. This raises the question of whether or not to use IL-1β inhibitors in cancer treatment.

RING domain-deficient BRCA1 promotes PARP inhibitor and platinum resistance

Patients with cancers that harbor breast cancer 1 (BRCA1) mutations initially respond well to platinum and poly(ADP-ribose) polymerase inhibitor (PARPi) therapy; however, resistance invariably arises in these patients and is a major clinical problem. The BRCA1185delAG allele is a common inherited mutation located close to the protein translation start site that is thought to produce a shortened, nonfunctional peptide. In this study, we investigated the mechanisms that lead to PARPi and platinum resistance in the SUM1315MO2 breast cancer cell line, which harbors a hemizygous BRCA1185delAG mutation. SUM1315MO2 cells were initially sensitive to PARPi and cisplatin but readily acquired resistance. PARPi- and cisplatin-resistant clones did not harbor secondary reversion mutations; rather, PARPi and platinum resistance required increased expression of a really interesting gene (RING) domain-deficient BRCA1 protein (Rdd-BRCA1). Initiation of translation occurred downstream of the frameshift mutation, probably at the BRCA1-Met-297 codon. In contrast to full-length BRCA1, Rdd-BRCA1 did not require BRCA1-associated RING domain 1 (BARD1) interaction for stability. Functionally, Rdd-BRCA1 formed irradiation-induced foci and supported RAD51 foci formation. Ectopic overexpression of Rdd-BRCA1 promoted partial PARPi and cisplatin resistance. Furthermore, Rdd-BRCA1 protein expression was detected in recurrent carcinomas from patients who carried germline BRCA1185delAG mutations. Taken together, these results indicate that RING-deficient BRCA1 proteins are hypomorphic and capable of contributing to PARPi and platinum resistance when expressed at high levels.

Epigenetic reprogramming of fallopian tube fimbriae in BRCA mutation carriers defines early ovarian cancer evolution

The exact timing and contribution of epigenetic reprogramming to carcinogenesis are unclear. Women harbouring BRCA1/2 mutations demonstrate a 30–40-fold increased risk of high-grade serous extra-uterine Müllerian cancers (HGSEMC), otherwise referred to as ‘ovarian carcinomas', which frequently develop from fimbrial cells but not from the proximal portion of the fallopian tube. Here we compare the DNA methylome of the fimbrial and proximal ends of the fallopian tube in BRCA1/2 mutation carriers and non-carriers. We show that the number of CpGs displaying significant differences in methylation levels between fimbrial and proximal fallopian tube segments are threefold higher in BRCA mutation carriers than in controls, correlating with overexpression of activation-induced deaminase in their fimbrial epithelium. The differentially methylated CpGs accurately discriminate HGSEMCs from non-serous subtypes. Epigenetic reprogramming is an early pre-malignant event integral to BRCA1/2 mutation-driven carcinogenesis. Our findings may provide a basis for cancer-preventative strategies.

Women with germline variants in BRCA genes are predisposed to ovarian cancer. In this study, the authors demonstrate that fimbrial tissue from the ovary, the site of ovarian cancer, in BRCA mutant carriers contains marked DNA methylation changes compared with the proximal region of the ovary.