Role In Breast Carcinogenesis Research Articles

Expression profiles of FABP4 and FABP5 in breast cancer: clinical implications and perspectives

The incidence of breast cancer continues to rise each year despite significant advances in diagnosis and treatment. Obesity-associated dysregulated lipid metabolism is believed to contribute to the increasing risk of breast cancer. However, the mechanisms linking lipid dysregulation to breast cancer risk and progression remain to be determined. The family of fatty acid binding proteins (FABPs) evolves to facilitate lipid transport and metabolism. As the predominant isoforms of FABP members expressed in breast tissue, adipose FABP (A-FABP, also known as FABP4) and epithelial FABP (E-FABP, FABP5) have been shown to play critical roles in breast carcinogenesis. In this study, we collected surgical breast tissue samples from 96 women with different subtypes of breast cancer and comprehensively analyzed the expression pattens of FABP4 and FABP5. We found that distinct expression profiles of FABP4 and FABP5 were associated with their unique roles in breast cancer development. FABP4, mainly expressed in breast stroma, especially in adipose tissue, likely supported neighboring tumor cell lymphovascular invasion through secretion from adipocytes. In contrast, FABP5, primarily expressed in epithelial-derived tumor cells, could promote tumor metastasis by enhancing lipid metabolism. Thus, elevated levels of FABP4 and FABP5 may serve as poor prognostic markers for breast cancer. Inhibiting the activity of FABP4 and/or FABP5 may offer a novel strategy for breast cancer therapy.

Lin28/let-7 axis in breast cancer.

Let-7 microRNAs are tumor suppressor microRNAs, and their reduced expression frequently occurs in various types of cancers, including breast cancer. A notable correlation exists between decreased let-7 microRNA levels and the overexpression of Lin28A and Lin28B, particularly in breast cancer cases with poor prognoses. Dysregulation of Wnt signaling significantly contributes to the upregulation of Lin28A and Lin28B in breast cancer. Both Lin28A and Lin28B operate from different cellular compartments to inhibit the biogenesis of let-7 microRNAs, which are essential for the post-transcriptional regulation of genes involved in key cellular functions such as proliferation, differentiation, and apoptosis. Decreased expression of let-7 microRNAs leads to the overexpression of oncogenes such as K-ras, C-myc, and SOX-2 in breast cancer. Overexpression of Lin28A associated with reduced let-7 microRNA levels is observed in estrogen receptor positive, estrogen receptor negative, and human epidermal growth factor receptor 2 positive breast cancers, whereas Lin28B overexpression with reduced let-7 microRNA levels occurs specifically in triple negative breast cancer. This review aims to dissect the molecular interplay between Lin28A, Lin28B, and let-7 microRNAs, elucidating their roles in breast carcinogenesis, metastasis, and the development of resistance to conventional treatments like radiation and chemotherapy. Additionally, the review addresses potential therapeutic avenues offered by let-7 microRNAs or their mimics, as well as Lin28A and Lin28B inhibitors, in the treatment of breast cancer.

Bovine Leukemia Virus and Human Breast Cancer: A Review of Clinical and Molecular Evidence.

Despite significant advancements in early diagnosis and treatment, breast cancer (BC) remains a major global health challenge. Ongoing research is essential to identify novel risk factors, implement innovative screening programs, and develop personalized treatment approaches. Among the various risk factors, infection with certain oncogenic viruses has emerged as a potential contributor to BC development. Increasing evidence suggests that bovine leukemia virus (BLV) may contribute to zoonotic infections in humans, with a potential role in BC initiation and progression. This review evaluates clinical and experimental data on BLV presence in both malignant and non-malignant breast tissues, exploring potential mechanisms through which BLV may access human breast tissue and contribute to carcinogenesis. Current data reveal a higher prevalence of BLV infection in BC tissues compared to non-tumor tissues, correlating with an increased risk of BC development. In this context, dairy and meat products from BLV-infected animals have been proposed as potential transmission sources. BLV-encoded proteins disrupt key oncogenic pathways, which support their possible role in breast carcinogenesis. However, the interpretation of these findings is limited by potential confounding factors such as genetic predisposition, environmental exposures, and dietary influences. Further research, including well-controlled epidemiological studies, longitudinal cohorts, and mechanistic investigations into BLV proteins in human breast cells, is necessary to determine its role in BC development.

Epigenetic regulation of HOXA2 expression affects tumor progression and predicts breast cancer patient survival

Accumulating evidence suggests that genetic and epigenetic biomarkers hold potential for enhancing the early detection and monitoring of breast cancer (BC). Epigenetic alterations of the Homeobox A2 (HOXA2) gene have recently garnered significant attention in the clinical management of various malignancies. However, the precise role of HOXA2 in breast tumorigenesis has remained elusive. To address this point, we conducted high-throughput RNA sequencing and DNA methylation array studies on laser-microdissected human BC samples, paired with normal tissue samples. Additionally, we performed comprehensive in silico analyses using large public datasets: TCGA and METABRIC. The diagnostic performance of HOXA2 was calculated by means of receiver operator characteristic curves. Its prognostic significance was assessed through immunohistochemical studies and Kaplan-Meier Plotter database interrogation. Moreover, we explored the function of HOXA2 and its role in breast carcinogenesis through in silico, in vitro, and in vivo investigations. Our work revealed significant hypermethylation and downregulation of HOXA2 in human BC tissues. Low HOXA2 expression correlated with increased BC aggressiveness and unfavorable patient survival outcomes. Suppression of HOXA2 expression significantly heightened cell proliferation, migration, and invasion in BC cells, and promoted tumor growth in mice. Conversely, transgenic HOXA2 overexpression suppressed these cellular processes and promoted apoptosis of cancer cells. Interestingly, a strategy of pharmacological demethylation successfully restored HOXA2 expression in malignant cells, reducing their neoplastic characteristics. Bioinformatics analyses, corroborated by in vitro experimentations, unveiled a novel implication of HOXA2 in the lipid metabolism of BC. Specifically, depletion of HOXA2 leaded to a concomitantly decreased expression of PPARγ and its target CIDEC, a master regulator of lipid droplet (LD) accumulation, thereby resulting in reduced LD abundance in BC cells. In summary, our study identifies HOXA2 as a novel prognosis-relevant tumor suppressor in the mammary gland.

The Overexpressed MicroRNAs miRs-182, 155, 493, 454, and U6 snRNA and Underexpressed let-7c, miR-328, and miR-451a as Potential Biomarkers in Invasive Breast Cancer and Their Clinicopathological Significance

Introduction: Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers. Methods: This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data. Results: Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations. Conclusion: We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice. Introduction: Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers. Methods: This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data. Results: Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations. Conclusion: We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice.

Unravelling the therapeutic potential of forkhead box proteins in breast cancer: An update (Review).

Unravelling the therapeutic potential of forkhead box proteins in breast cancer: An update (Review).

Abstract 4431: Steroid hormone metabolites and mammographic breast density in premenopausal women

Abstract Background: Steroid hormones influence breast tissue development and play a role in breast carcinogenesis. Their associations with mammographic breast density (MBD), an established risk factor for breast cancer, are less clear. We, therefore, investigated the associations of steroid hormone metabolites with MBD in premenopausal women. Methods: Our study population consists of 705 premenopausal women recruited during their annual screening mammogram at the Washington University School of Medicine, St. Louis, MO. We assessed volumetric percent density (VPD), dense volume (DV), and non-dense volume (NDV) using Volpara. We assayed 54 steroid hormone metabolites from fasting blood samples at Metabolon. Linear regression models were used, after adjusting for covariates, to estimate the least square means of VPD, DV, and NDV across tertiles (T) of each metabolite. Sensitivity analysis was performed among the subset of participants with a history of oral contraceptive use (OCP). We used the Benjamini-Hochberg procedure to correct for multiple tests to control the false discovery rate (FDR) at a 5% level. Results: Five androgen metabolites (androstenediol (3beta,17beta) monosulfate 2, androstenediol (3beta,17beta) disulfate 1, 5alpha-androstan-3alpha,17beta-diol monosulfate 2, 5alpha-androstan-3alpha,17beta-diol disulfate, and 5alpha-androstan-3beta,17beta-diol disulfate) and two corticosteroid metabolites (tetrahydrocortisone glucuronide 5, and cortolone glucuronide 1) were inversely associated with VPD. Androstenediol (3beta,17beta) disulfate 1, and 5alpha-androstan-3alpha,17beta-diol disulfate displayed the strongest associations with VPD. The mean VPD decreased across tertiles of androstenediol (3beta,17beta) disulfate 1 from 9.0% in T1 to 8.5% in T2, and 7.5% in T3 (FDR p-value=0.02). Similarly, the mean VPD decreased from 8.8% in T1 to 8.4% in T2, and 7.6% in T3 of 5alpha-androstan-3alpha,17beta-diol disulfate (FDR p-value=0.03). Progestin steroid metabolites appeared to be positively associated with VPD but only 5alpha-pregnan-3beta,20alpha-diol monosulfate 2 was marginally significant after FDR correction (7.5% in T1, 8.3% in T2, and 8.8% in T3; FDR p-value=0.06). Four metabolites (three corticosteroids and one androgenic steroid) were positively associated with NDV. No metabolite was associated with DV. In sensitivity analysis limited to OCP users, mean VPDs were lower but the directions of associations were similar to those observed in the overall analysis. Conclusion: We report novel associations of corticosteroids and androgen metabolites with breast density in premenopausal women. Our findings shed important new insights into hormonal biomarkers and MBD. Citation Format: Kayode A. Matthew, Girish K. Vanapali, Kayla R. Getz, Myung S. Jeon, Chongliang Luo, Xingyi Guo, Jingqin Luo, Adetunji T. Toriola. Steroid hormone metabolites and mammographic breast density in premenopausal women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4431.

MALAT1 Long Non-coding RNA and Its Role in Breast Carcinogenesis.

Our genome consists not only of protein-coding DNA, but also of the non-coding part that plays a very important role in the regulation of all cellular processes. A part of the non-coding genome comes with non-coding RNAs (ncRNAs), and disruption of the functional activity of these RNAs may be associated with oncogenesis in various cancer types. There exist two types of ncRNAs: small and long non-coding RNAs, which are classified according to their transcript length. Long non-coding metastasis-associated lung adenocarcinoma transcript 1, MALAT1 RNA (NEAT2), is a long non-coding RNA of particular interest. The aforementioned transcript takes part in the regulation of numerous cellular processes and pathogenesis of different malignant tumors, including breast tumors. This review focuses on experimental and clinical studies into the role of MALAT1 in carcinogenesis and the progression of breast cancer.

The effects of MYC on exosomes derived from cancer cells in the context of breast cancer.

MYC amplification and overexpression in breast cancer occur 16% and 22%, respectively, and MYC has a linchpin role in breast carcinogenesis. Emerging evidence has started to shed light on central role of MYC in breast cancer progression. On the contrary, tumor-derived exosomes and their cargo molecules are required for the modulation of the tumor environment and to promote carcinogenesis. Still, how MYC regulates tumor-derived exosomes is still a matter of investigation in the context of breast cancer. Here, we investigated for the first time how MYC affects the biological functions of normal breast cells cocultured with exosomes derived from MYC-expression manipulated breast cancer cells. Accordingly, exosomes were isolated from MCF-7 and MDA-MB-231 cells that MYC expression was manipulated through siRNAs or lentiviral vectors by using exosome isolation reagent. Then, normal breast epithelial MCF-10A cells were treated with breast cancer cell-derived exosomes. The cellular activity of MCF-10A was investigated by cell growth assay, wound healing assay, and transwell assay. Our results suggested that MCF-10A cells treated with exosomes derived from MYC-overexpressing breast cancer cells demonstrated higher proliferation and migration capability compared with nontreated cells. Likewise, MCF-10A cells treated with exosomes derived from MYC-silenced cancer cells did not show high proliferation and invasive capacity. Overall, MYC can drive the functions of exosomes secreted from breast cancer cells. This may allow exploring a new mechanism how tumor cells regulate cancer progression and modulate tumor environment. The present study clears the way for further researches as in vivo studies and multi-omics that clarify exosomal content in an MYC-dependent manner.

Abstract 5289: Proteomic profile of breast carcinomas with unbalanced levels of progesterone receptor isoforms

Abstract Preclinical studies indicate that progesterone receptors (PR) play a relevant role in breast carcinogenesis. Even more, a misbalanced expression of PR isoforms A (PRA) and B (PRB) differentially affect breast cancer progression and only tumors with higher levels of PRA than PRB (PRA-H) respond to an antiprogestin treatment. There are controversial results regarding the prognosis of PRA-H luminal tumors compared with those with the opposite ratio (PRB-H tumors) highlighting the necessity to further understand the role of PR isoforms in tumor progression and to develop novel methods to discriminate these tumors without performing western blot studies. Along this line we have previously studied the transcriptome of PRA-H or PRB-H breast cancer samples, thus our aim is to expand these results and compare the proteome profile of PRA-H and PRB-H samples obtained from postmenopausal breast cancer patients. Nuclear (Nuc) and cytosolic (Cyt) protein fractions were obtained from 18 breast cancer samples classified as PRA-H or PRB-H and they were studied by LC-MS/MS (UltiMate 3000 LC system - Q Exactive HF-X mass spectrometer - Thermo). We observed 289 differentially deregulated proteins in Cyt (164 down and 125 up) and 301 in Nuc extracts (131 down and 170 up; logFC > 1, pval < 0.05). Gene set enrichment analysis of the Nuc fractions showed biological processes related to Cell junction organization (pval = 8,87e-05), Collagen formation (pval = 0,0005), and Cell-Cell communication processes (pval = 0,0035) in PRB-H tumors; while in PRA-H tumors, pathways related to Innate Immune System (pval = 8,8e-05), Class I MHC mediated antigen processing & presentation (pval = 8e-05) and Stabilization of p53 (pval = 0,0051) processes were enriched. Similar trends were observed in Cyt fractions. Individual candidates that were overrepresented in both fractions in PRB-H tumors are BAG3 and GH3, related to cell proliferation, and VWF, related to the activation of the Akt pathway. Overrepresented proteins in both fractions of PRA-H tumors are BST2, IFT27 related to invasion, and MIF associated with poor prognosis. As we were interested in looking for differential expressed proteins that could be tested in plasma samples to discriminate both tumor types, using the Vertebrate Secretome Database we focused on those that might be secreted. Noteworthy is CBP1 which was overrepresented in the PRB-H tumors and this was in agreement with the RNA-Seq data and with results obtained using preclinical models, repurposing this protein as one candidate of concern in the search for biomarkers. Other secretory proteins of interest are SFRP2 and SERPIND1, both highly expressed in PRA-H Cyt fractions. In conclusion, this study underscores the biological differences between PRA-H and PRB-H breast carcinomas and provides candidates that deserve to be tested as surrogate markers in plasma to discriminate patients that may benefit from an antiprogestin treatment. Citation Format: Andres M. Elia, Jana Sanchez, Rui Vitorino, Leo Saldain, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Javier Muñoz, Paola Rojas, Luisa Helguero, Claudia Lanari. Proteomic profile of breast carcinomas with unbalanced levels of progesterone receptor isoforms. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5289.

Mitochondrial genome in sporadic breast cancer: A case control study and a proteomic analysis in a Sinhalese cohort from Sri Lanka.

Breast cancer is the commonest malignancy in women and the majority occurs sporadically with no hereditary predisposition. However, sporadic breast cancer has been studied less intensively than the hereditary form and to date hardly any predictive biomarkers exist for the former. Furthermore, although mitochondrial DNA variants have been reported to be associated with breast cancer, findings have been inconsistent across populations. Thus we carried out a case control study on sporadic breast cancer patients and healthy controls of Sinhalese ethnicity (N = 60 matched pairs) in order to characterize coding region variants associated with the disease and to identify any potential biomarkers. Mitochondrial genome was fully sequenced in 30 pairs and selected regions were sequenced in the remaining 30 pairs. Several in-silico tools were used to assess functional significance of the variants observed. A number of variants were identified among the patients and the controls. Missense variants identified were either polymorphisms or rare variants. Their prevalence did not significantly differ between patients and the healthy controls (matched for age, body mass index and menopausal status). MT-CYB, MT-ATP6 and MT-ND2 genes showed a higher mutation rate. A higher proportion of pre-menopausal patients carried missense and pathogenic variants. Unique combinations of missense variants were seen within genes and these occurred mostly in MT-ATP6 and MT-CYB genes. Such unique combinations that occurred exclusively among the patients were common in obese patients. Mitochondrial DNA variants may have a role in breast carcinogenesis in obesity and pre-menopause. Molecular dynamic simulations suggested the mutants, G78S in MT-CO3 gene and T146A in MT-ATP6 gene are likely to be more stable than their wild type counterparts.

Genetic profiling of different phenotypic subsets of breast cancer stem cells (BCSCs) in breast cancer patients

BackgroundBreast cancer stem cells (BCSCs) have a crucial role in breast carcinogenesis, development, and progression. The aim of the current study is to characterize the BCSCs through the genetic profiling of different BCSCs phenotypic subsets to determine their related genetic pathways.MethodsFresh tumor tissue samples were obtained from 31 breast cancer (BC) patients for (1) Mammosphere culture. (2) Magnetic separation of the BCSCs subsets using CD24, CD44, and CD326 Microbeads. (3) Flow cytometry (FCM) assay using CD44, CD24, and EpCAM. (4) RT-PCR profiler Arrays using stem cell (SC) panel of 84 genes for four group of cells (1) CD44+/CD24−/EpCAM− BCSCs, (2) CD44+/CD24− /EpCAM+ BCSCs, (3) mammospheres, and (4) normal breast tissues.ResultsThe BCSCs (CD44+/CD24−/EpCAM−) showed significant downregulation in 13 genes and upregulation in 15, where the CD44, GJB1 and GDF3 showed the maximal expression (P = 0.001, P = 0.003 and P = 0.007); respectively).The CD44+/CD24−/EpCAM+ BCSCs showed significant upregulation in 28 genes, where the CD44, GDF3, and GJB1 showed maximal expression (P < 0.001, P = 0.001 and P = 0.003; respectively). The mammospheres showed significant downregulation in 9 genes and a significant upregulation in 35 genes. The maximal overexpression was observed in GJB1 and FGF2 (P = 0.001, P = 0.001; respectively).The genes which achieved significant overexpression in all SC subsets were CD44, COL9A1, FGF1, FGF2, GDF3, GJA1, GJB1, GJB2, HSPA9, and KRT15. While significant downregulation in BMP2, BMP3, EP300, and KAT8.The genes which were differentially expressed by the mammospheres compared to the other BCSC subsets were CCND2, FGF3, CD4, WNT1, KAT2A, NUMB, ACAN, COL2A1, TUBB3, ASCL2, FOXA2, ISL1, DTX1, and DVL1.ConclusionBCSCs have specific molecular profiles that differ according to their phenotypes which could affect patients’ prognosis and outcome.

Abstract 3631: Transcriptome-wide association study identifies novel genes associated with breast cancer susceptibility in Latinas

Abstract Background: Genetic susceptibility to breast cancer has been studied extensively in European ancestry populations, but few studies have addressed genetic susceptibility in non-European women. Latinas are a genetically diverse group with contributions from European, African, and Indigenous American ancestries. Genome-wide association studies (GWAS) have identified unique variants in this population, particularly at the 6q25 locus. We conducted a transcriptome-wide association study (TWAS) to identify novel genes associated with risk of breast cancer in Latinas. Methods: We used individual level GWAS data from 2,396 Latina cases and 6,505 Latina controls from the studies in Northern California (San Francisco Bay Area Breast Cancer Study, Northern California Breast Cancer Family Registry and Kaiser Permanente Genetic Epidemiology Research on Aging Cohort), Southern California (Multi-ethnic Cohort) and Mexico (CAMA study). We analyzed the association between genetically predicted whole blood (WB) gene expression and breast cancer risk using newly developed TWAS models based on 784 Mexican American individuals. We also conducted parallel analyses using breast mammary tissue (BT) TWAS models from GTEx v8. All analyses were adjusted for age, ancestry, and study. Associations with false discovery rate (FDR) probability &amp;lt;0.05 were considered statistically significant. Results: At FDR&amp;lt;0.05, we identified 20 genes from BT and 39 genes from WB. Seven of the genes were significantly associated in both the WB models and GTEx BT models. Increased expression of MIB2 (pFDR = 4.74x10-17 (WB) and 1.22x10-4 (BT)), NBPF26 (pFDR = 1.30x10-7 (WB) and 7.43x10-8 (BT)), SLC35E2B (pFDR = 1.12x10-4 (WB) and 5.47x10-5 (BT)), and FAM30A (pFDR = 1.18x10-10 (WB) and 9.27x10-3 (BT)) was associated with increased risk of breast cancer risk, whereas increased expression of SLC35E2A (pFDR = 8.17x10-6 (WB) and 1.55x10-3 (BT)) and HCP5B (pFDR = 1.84x10-3 (WB) and 2.19x10-3 (BT)) was associated with decreased breast cancer risk. Increased expression of PDGFA was associated with increased risk (pFDR = 1.30x10-7) in GTEx BT reference models but decreased risk (pFDR = 2.34x10-10) in the ancestry-specific WB model. Conclusion: Our study is the first TWAS investigating the relationship between genetically predicted gene expression and breast cancer risk in Latinas. By leveraging gene expression prediction models that capture eQTLs that are more common in populations with Indigenous American ancestry, we have identified some novel genes associated with breast cancer risk in Latinas. Of these, MIB2 is a strong candidate for a mechanistic role in breast carcinogenesis in Latinas. MIB2 is involved in Notch signaling which plays an important role in breast carcinogenesis via its mismatched receptor-ligand interaction. Our study highlights the role of ancestry-based prediction models in TWAS analyses. Citation Format: Pooja Middha Kapoor, Angel C. Mak, Linda Kachuri, Donglei Hu, Scott Huntsman, Lawrence H. Kushi, Christopher Haiman, Esther M. John, Gabriela Torres-Mejia, Esteban G. Burchard, Susan L. Neuhausen, Laura Fejerman, Elad Ziv. Transcriptome-wide association study identifies novel genes associated with breast cancer susceptibility in Latinas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3631.

Urinary concentration of endocrine-disrupting phthalates and breast cancer risk in Indian women: A case-control study with a focus on mutations in phthalate-responsive genes

Urinary concentration of endocrine-disrupting phthalates and breast cancer risk in Indian women: A case-control study with a focus on mutations in phthalate-responsive genes

High DNMT1 Expression in Stromal Fibroblasts Promotes Angiogenesis and Unfavorable Outcome in Locally Advanced Breast Cancer Patients

BackgroundActive breast cancer-associated fibroblasts (CAFs) play a leading role in breast carcinogenesis through promoting angiogenesis and resistance to therapy. Consequently, these active stromal cells have significant influence on patient outcome. Therefore, we explored here the role of the DNA methyltransferase 1 (DNMT1) protein in CAF-dependent promotion of angiogenesis as well as the prognostic power of DNMT1 level in both cancer cells and their adjacent CAFs in locally advanced breast cancer patients.MethodsWe applied immunohistochemistry to evaluate the level of DNMT1 in breast cancer tissues and their adjacent normal counterparts. Quantitative RT-PCR and immunoblotting were performed to investigate the role of DNMT1 in regulating the expression of pro-angiogenic genes in active CAFs and also their response to the DNMT1 inhibitors decitabine (DAC) as well as eugenol.ResultsWe have shown that DNMT1 controls the pro-angiogenic potential of CAFs both in vitro and in vivo through positive regulation of the expression/secretion of 2 important pro-angiogenic factors VEGF-A and IL-8 as well as their upstream effectors mTOR and HIF-1α. To confirm this, we have shown that these DNMT1-related pro-angiogenic effects were suppressed by 2 DNMT1 inhibitors decitabine and eugenol. Interestingly, in a cohort of 100 tumors from locally advanced breast cancer patients (LABC), we have shown that high expression of DNMT1 in tumor cells and their adjacent stromal fibroblasts is correlated with poor survival of these patients.ConclusionDNMT1 upregulation in breast stromal fibroblasts promotes angiogenesis via IL-8/VEGF-A upregulation, and correlates well with poor survival of LABC patients.

Residential proximity to industrial pollution and mammographic density

Residential proximity to industrial pollution and mammographic density

Associations between the Levels of Estradiol-, Progesterone-, and Testosterone-Sensitive MiRNAs and Main Clinicopathologic Features of Breast Cancer.

Despite the existing advances in the diagnosis and treatment of breast cancer (BC), the search for markers associated with the clinicopathological features of BC is still in demand. MiRNAs (miRs) have potential as markers, since a change in the miRNA expression profile accompanies the initiation and progression of malignant diseases. The receptors for estrogen, androgen, and progesterone (ER, AR, and PR) play an important role in breast carcinogenesis. Therefore, to search for miRNAs that may function as markers in BC, using bioinformatic analysis and the literature data, we selected 13 miRNAs whose promoter regions contain binding sites for ER or AR, or putative binding sites for ER, AR, and PR. We quantified their expression in MCF-7 cells treated with estradiol, progesterone, or testosterone. The levels of miRNAs sensitive to one or more of these hormones were quantified in BC samples (n = 196). We discovered that high expression levels of miR-190b in breast tumor tissue indicate a positive ER status, and miR-423 and miR-200b levels differ between patients with and without HER2 amplification. The miR-193b, -423, -190a, -324, and -200b levels were associated with tumor size or lymph node status in BC patients, but the presence of these associations depended on the status and expression level of ER, PR, HER2, and Ki-67. We also found that miR-21 expression depends on HER2 expression in ER- and/or PR-positive BC. The levels of miRNA were significantly different between HER2 0 and HER2 1+ tumors (p = 0.027), and between HER2 0 and HER2 2+, 3+ tumors (p = 0.005).

Human Papillomavirus in Breast Carcinogenesis: A Passenger, a Cofactor, or a Causal Agent?

Simple SummaryBreast cancer (BC) is the most frequent tumor in women worldwide. A minority of BC patients have a family history of the disease, suggesting the importance of environmental and lifestyle factors. Human papillomavirus (HPV) infection has been detected in a subset of tumors, suggesting a potential role in BC. In this review, we summarized relevant information in respect to this topic and we propose a model of HPV-mediated breast carcinogenesis. Evidence suggests that breast tissue is accessible to HPV, which may be a causal agent of BC in a subset of cases.Breast cancer (BC) is the most commonly diagnosed malignancy in women worldwide as well as the leading cause of cancer-related death in this gender. Studies have identified that human papillomavirus (HPV) is a potential risk factor for BC development. While vaccines that protect against oncogenic HPVs infection have been commercially available, global disparities persist due to their high cost. Interestingly, numerous authors have detected an increased high risk (HR)-HPV infection in BC specimens when compared with non-tumor tissues. Therefore, it was suggested that HR-HPV infection could play a role in breast carcinogenesis in a subset of cases. Additional epidemiological and experimental evidence is still needed regarding the role of HR-HPV infection in the development and progression of BC.

The Oncogenic Roles of JC Virus T Antigen in Breast Carcinogenesis.

Purpose: JC virus (JCV) infects 80–90% of the population and results in progressive multifocal leukoencephalopathy upon immunodeficiency. The study aimed to pathologically clarify the oncogenic roles of T antigen in human breast cancers.Methods: Breast cancer, dysplasia, and normal tissues were examined for T antigen of JCV by nested and real-time PCR. The positive rate or copy number of T antigen was compared with clinicopathological parameters of breast cancer. JCV existence was morphologically detected by immunohistochemistry and in situ PCR. T antigen was examined by Western blot using frozen samples of breast cancer and paired normal tissues.Results: According to nested PCR, the positive rate of breast ductal or lobular carcinoma was lower than that of normal tissue (p < 0.05). T antigen existence was negatively correlated with E-cadherin expression and triple-negative breast cancer (p < 0.05), but positively correlated with lymph node metastasis and estrogen receptor and progestogen receptor expression (p < 0.05). Quantitative PCR showed that JCV copies were gradually decreased from normal, dysplasia to cancer tissues (p < 0.05). JCV T antigen copy number was lower in ductal adenocarcinoma than in normal tissue (p < 0.05), in line with in situ PCR and immunohistochemistry. JCV copies were negatively correlated with tumor size and E-cadherin expression (p < 0.05), but positively correlated with G grading of breast cancer (p < 0.05). Western blot also indicated weaker T antigen expression in breast cancer than normal tissues (p < 0.05).Conclusion: JCV T antigen might play an important role in breast carcinogenesis. It can be employed as a molecular marker for the differentiation and aggressive behaviors of breast cancer.

Marine Cyclic Dipeptide Cyclo (L-Leu-L-Pro) Protects Normal Breast Epithelial Cells from tBHP-induced Oxidative Damage by Targeting CD151

Background: Oxidative stress plays a key role in breast carcinogenesis. Cyclo (L-Leu-L-Pro) (CLP) is a homodetic cyclic dipeptide with 2,5-diketopiperazine scaffold isolated from marine actinobacteria. This study aimed to evaluate the protective activity of CLP and linear - (L-Leu-L-Pro) (LP) from tert-butyl hydroperoxide (tBHP)-induced damage using normal breast epithelial cell line model (MCF-12A). Methods: The cytoprotective activity was evaluated by detecting the changes in intracellular ROS, mitochondrial superoxide, hydroxyl radical, hydrogen peroxide, and lipid peroxidation detection assays as well as cytotoxic assays of MTT, LDH assays and phase contrast microscopy. Genoprotective activity was evaluated by (Apurinic/Apyrimidinic) AP site, alkaline Comet, and 8-hydroxy-2-deoxyguanosine assays. Results: The marine cyclic peptide, CLP, significantly protected MCF-12A cells by scavenging tBHP induced intracellular ROS such as super oxide, hydroxyl radicals and hydrogen peroxide, and by reducing the cytotoxicity and genotoxicity effect compared to LP. Moreover, the results showed that CD151 gene silencing by shRNA significantly reduced the overexpression of CD151, tBHP-induced ROS generation, cytotoxicity and genotoxicity in MCF-12A cells. The overexpression of CD151 caused increased levels of cytochrome P450, but was reduced following the application of CD151shRNA and CLP which led to elevated levels of intracellular ROS. Conclusion: In the present study we noticed that CD151 gene silencing by shRNA and treatment with CLP have similar effects on reducing the intracellular ROS. This study uncovers the protective activity of CLP against a CD151-mediated oxidative stress-induced cellular damage. Our observations suggest that the anti-stress and anti-inflammation properties of CLP might have implications in cancer and are worth testing in cancer cell lines and tumor cells.