BRCA1 the Versatile Defender: Molecular to Environmental Perspectives

Circ-ITCH promotes the ubiquitination degradation of HOXC10 to facilitate osteogenic differentiation in disuse osteoporosis through stabilizing BRCA1 mRNA via IGF2BP2-mediated m6A modification

BACKGROUND

Osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs) facilitated by mechanical loading is a promising therapy for disuse osteoporosis (DOP), however, it is difficult to implement mechanical loading for a majority of patients. Our study aims to identify circ-ITCH-mediated novel approach to facilitate osteogenic differentiation in DOP.

METHODS

A rat DOP model and human BM-MSCs under microgravity condition were generated as in vivo and in vitro models of DOP, respectively. The bone mineral density (BMD) and bone parameters were examined in rats. The histological changes of bones and mineralization were monitored by H&E, Alcian blue and Alizarin red S staining. Co-IP was employed to examine the ubiquitination of HOXC10 and the interaction between HOXC10 and BRCA1. The direct associations among circ-ITCH, IGFBP2 and BRCA1 mRNA were assessed by RIP, FISH and RNA pull-down assays.

RESULTS

Circ-ITCH was downregulated in rat model of DOP and BM-MSCs under microgravity stimulation. Circ-ITCH overexpression promoted osteogenic differentiation in BM-MSCs under microgravity condition. The altered bone parameters, such as BMD, trabecular number (Tb.N), trabecular separation (Tb.Sp), trabecular thickness (Tb.Th), and bone microstructure in DOP rats were rescued by circ-ITCH overexpression. Mechanistically, circ-ITCH enhanced the ubiquitination degradation of HOXC10 through enhancing BRCA1 mRNA stability. Circ-ITCH directly bound to IGF2BP2 protein to stabilize BRCA1 mRNA via m6A modification, thus facilitating osteogenic differentiation in BM-MSCs under microgravity condition.

CONCLUSION

Circ-ITCH stabilized BRCA1 mRNA via IGF2BP2-mediated m6A modification, thereby facilitating the ubiquitination degradation of HOXC10 to promote osteogenic differentiation in DOP.

Regulation of pathway choice in DNA repair after double-strand breaks

DNA damage signaling is a highly coordinated cellular process which is required for the removal of DNA lesions. Amongst the different types of DNA damage, double-strand breaks (DSBs) are the most harmful type of lesion that attenuates cellular proliferation. DSBs are repaired by two major pathways-homologous recombination (HR), and non-homologous end-joining (NHEJ) and in some cases by microhomology-mediated end-joining (MMEJ). Preference of the pathway depends on multiple parameters including site of the DNA damage, the cell cycle phase and topology of the DNA lesion. Deregulated repair response contributes to genomic instability resulting in a plethora of diseases including cancer. This review discusses the different molecular players of HR, NHEJ, and MMEJ pathways that control the switch among the different DSB repair pathways. We also highlight the various functions of chromatin modifications in modulating repair response and how deregulated DNA damage repair response may promote oncogenic transformation.

Mammary Cancer Models: An Overview from the Past to the Future

Breast cancer research heavily relies on diverse model systems to comprehend disease progression, develop novel diagnostics, and evaluate new therapeutic strategies. This review offers a comprehensive overview of mammary cancer models, covering both ex vivo and in vivo approaches. We delve into established techniques, such as cell culture and explore cutting-edge advancements, like tumor-on-a-chip and bioprinting. The in vivo section encompasses spontaneous, induced, and transplanted models, genetically engineered models, chick chorioallantoic membrane assays, and the burgeoning field of in silico models. Additionally, this article briefly highlights the key discoveries made using these models, significantly enhancing our understanding of breast cancer. In essence, this article serves as a comprehensive compass, charting the trajectory of mammary cancer modeling from its early beginnings to the promising vistas of tomorrow.

Ibuprofen modulates macrophage polarization by downregulating poly (ADP-ribose) polymerase 1

Ibuprofen, a non-steroidal drug, is well known for its anti-inflammatory activity. The effects of ibuprofen on the polarization of macrophages are still not clear. Herein, we used THP-1 monocyte-derived macrophages to find that ibuprofen has inhibitory effects on the polarization of both classically activated M1 macrophages and alternatively activated M2 macrophages by downregulating NF-κB and JAK/STAT signaling pathways. During M1 or M2 polarization, ibuprofen also downregulated the expression of poly (ADP-ribose) polymerase 1 (PARP1). Furthermore, knockdown of PARP1 by either small interfering RNA or PARP1 inhibitor PJ34 can exert inhibitory effects on the polarization of M1 and M2, and alter the immune response of macrophages to the infection of Mycobacterium tuberculosis H37Ra. The results demonstrate that PARP1 plays a regulatory role in the ibuprofen-modulated polarization of macrophage, revealing the interplay between the DNA repair response process and macrophage polarization.

BRCA1/2 Mutations and Breast/Ovarian Cancer Risk: A New Insights Review

Breast and ovarian cancers are significant global health concerns, and understanding their genetic underpinnings is essential for effective prevention and cure. This narrative review provides a comprehensive analysis of studies conducted between 1994 and June 2024, focusing on the link between specific mutations in the breast cancer susceptibility gene 1 (BRCA1) and breast cancer susceptibility gene 2 (BRCA2) and the associated risks of both breast and ovarian cancers. It encompasses the findings of various works, including observational studies and molecular profiling analyses. Conducted on large international cohorts, these studies present compelling evidence of the relationship between different BRCA1 and BRCA2 mutations and the varying risks of breast and ovarian cancer. Furthermore, this review highlights the significance of nonsense-mediated decay mutations and their impact on cancer risk, particularly concerning the age of breast cancer onset. The implications of these findings are far-reaching, offering valuable information for risk assessment and decision-making in managing individuals who carry BRCA1 or BRCA2 mutations. The molecular subtyping profile BluePrint is discussed as a potential tool for enhancing clinical care by aiding the selection of appropriate treatment options, such as endocrine therapy or chemotherapy, based on the tumor's molecular characteristics. In conclusion, we establish a robust link between specific BRCA1 and BRCA2 gene mutations and increased susceptibility to breast and ovarian cancers. These mutations impact cancer onset age and severity, underscoring the need for targeted testing and screening. The current study enhances cancer detection, prevention, and cure strategies.

Comprehensive Analysis of the Significance of Breast Cancer Gene 1 (BRCA-1) in Bladder Cancer

Background

Bladder carcinoma (BLCA) is characterized by high morbidity, mortality, and treatment costs. Breast cancer gene 1 (BRCA1), a tumor suppressor gene, inhibits the development of malignant tumors. However, research on the significance of BRCA1 in BLCA is limited. This study aims to explore the importance of BRCA1 in BLCA using bioinformatic methods and immunohistochemistry.

Methods

Gene expression, clinical, and survival data were collected from the TCGA databases through the UCSC Xena platform (http://xena.ucsc.edu/). The TPM data from the TCGA and GETEx databases were integrated using the GEPIA database (http://GEPIA.cancer-pku.cn). The study then explored the differential expression, survival prognosis, functional enrichment, and immune cell infiltration analyses of BRCA1 in BLCA. A PPI network of BRCA1 was constructed using the STRING database, and a BRCA1-associated gene-gene interaction network was generated using the GeneMANIA database. Immunohistochemistry (IHC) assays were performed to verify the expression levels of BRCA1 in bladder tumour tissues and adjacent normal tissues.

Results

BRCA1 is associated with BLCA. Differential analysis indicated that BRCA1 acts as a risk factor for BLCA but does not show significant expression differences across genders, stages, tumor stages, lymph node stages, or metastasis stages. Additionally, staging was based on the eighth edition of the American Joint Committee on Cancer (AJCC) for BLCA. Co-expression network and Gene Set Enrichment Analysis (GESA) confirmed that BRCA1 is involved in various BLCA pathways. Furthermore, BRCA1 expression was also linked to immune cell infiltration. However, survival prognosis analysis revealed no significant correlation between the prognosis of BLCA and BRCA1.

Conclusion

We demonstrated that BRCA1 is a prospective predicted and immunological biomarker in BLCA, offering new avenues for potential therapies.

Exploring the profound link: Breastfeeding's impact on alleviating the burden of breast cancer - A review

Breastfeeding has emerged as a critical factor in understanding and potentially mitigating the risk of breast cancer among women. This review delves into the intricate relationship between breastfeeding and breast cancer, elucidating the biological mechanisms, protective effects, and broader implications for public health. Epidemiological evidence consistently demonstrates a correlation between breastfeeding and a reduced risk of breast cancer, with longer durations of lactation showing a dose-dependent decrease in risk. The biological nexus between breastfeeding and breast cancer involves hormonal changes and the elimination of potentially damaged cells, influencing breast tissue and potentially mitigating carcinogenesis. Moreover, breastfeeding appears to impact tumor subtypes and aggressiveness, particularly demonstrating associations with lower risks of hormone receptor-negative and certain aggressive breast cancer subtypes. Recognizing the significance of breastfeeding in reducing breast cancer risk has profound public health implications, necessitating comprehensive support, education, and policies to encourage and facilitate breastfeeding.

The Link between Autosomal Dominant Polycystic Kidney Disease and Chromosomal Instability: Exploring the Relationship

In autosomal dominant polycystic kidney disease (ADPKD) with germline mutations in a PKD1 or PKD2 gene, innumerable cysts develop from tubules, and renal function deteriorates. Second-hit somatic mutations and renal tubular epithelial (RTE) cell death are crucial features of cyst initiation and disease progression. Here, we use established RTE lines and primary ADPKD cells with disease-associated PKD1 mutations to investigate genomic instability and DNA damage responses. We found that ADPKD cells suffer severe chromosome breakage, aneuploidy, heightened susceptibility to DNA damage, and delayed checkpoint activation. Immunohistochemical analyses of human kidneys corroborated observations in cultured cells. DNA damage sensors (ATM/ATR) were activated but did not localize at nuclear sites of damaged DNA and did not properly activate downstream transducers (CHK1/CHK2). ADPKD cells also had the ability to transform, as they achieved high saturation density and formed colonies in soft agar. Our studies indicate that defective DNA damage repair pathways and the somatic mutagenesis they cause contribute fundamentally to the pathogenesis of ADPKD. Acquired mutations may alternatively confer proliferative advantages to the clonally expanded cell populations or lead to apoptosis. Further understanding of the molecular details of aberrant DNA damage responses in ADPKD is ongoing and holds promise for targeted therapies.