Tumor Suppressor In Breast Cancer Research Articles

Abstract C059: SELENOF is a novel tumor suppressor and a new target to overcome breast cancer racial disparity

Abstract African American women die of breast cancer at a much higher rate than Caucasian women. While the reasons behind this racial disparity are multifactorial, recent findings point to biological components that remain to be fully elucidated. We have recently identified SELENOF as a new tumor suppressor in breast cancer. Consequently, its reduction or loss may drive disease progression and poor outcome. Conversely, we have shown that restoring SELENOF expression elicited anti-tumor activity. Therefore, therapeutic strategies to mitigate the loss of SELENOF may be exploited to improve outcome for patients affected by the loss of SELENOF. Based on two different Chicago-based cohorts, we reported that the breast tumors from African Americans exhibited a 5-10-fold higher frequency of SELENOF single nucleotide polymorphisms (SNPs) compared to Caucasians; these genetic variations result in attenuated translation of SELENOF and thus reduced SELENOF levels. This is supported by preliminary data showing that SELENOF expression is significantly lower in breast tumors from African American patients compared to Caucasians, and lower SELENOF expression predicts shorter survival in these patients. Our goal is to elucidate the role of SELENOF in breast cancer and determine its impact on breast tumorigenesis. We hypothesize that either enhancing SELENOF levels or mimicking its downstream signaling can be exploited to mitigate the loss of SELENOF and elicit anti-tumor activity. Targeting tumor suppressors remains challenging. We identified the eukaryotic initiation factor 4a3 (eIF4a3) as a putative translational repressor of SELENOF, and our preliminary data shows that pharmacologic inhibition of eIF4a3 results in increased SELENOF protein levels. We also found that SELENOF overexpression induces cell death by engaging the inositol-requiring enzyme 1 (IRE1) to determine cell fate. The therapeutic strategies under investigation are likely to result in novel and more effective personalized medicine, and may help close the breast cancer racial disparity gap. Citation Format: Roudy C. Ekyalongo, Alexandra Zigrossi, Brenna Flowers, Alan M. Diamond, Irida Kastrati. SELENOF is a novel tumor suppressor and a new target to overcome breast cancer racial disparity [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C059.

Integrative Analysis of Genetic and Epigenetic Alterations in the CBX7 Gene Reveals Its Tumor-Suppressive Function by Regulating the Cell Cycle in Human Breast Cancer

CBX7 is a member of the chromobox gene family, which plays an important role in epigenetic transcriptional regulation. In this study, we found that compared to normal mammary tissues, mRNA levels of CBX7 are consistently significantly downregulated in breast cancers (BCs) across different datasets. Integrative multiomics analysis revealed the genetic and epigenetic mechanisms for the loss of CBX7 expression in BCs. Lower expression levels of CBX7 are significantly associated with shorter overall, disease-free, and distant metastasis-free survival of patients with BC. These prognostic impacts of CBX7 are independent of estrogen receptor status and PAM50 molecular subtypes. Coexpression analysis identified 207 genes consistently coexpressed with CBX7 (157 negatively and 50 positively). Gene Ontology, KEGG, and Reactome enrichment analysis revealed that cell cycle‑, DNA replication‑, and mitosis-related pathways are significantly overrepresented within the set of CBX7 negatively coexpressed genes, suggesting that CBX7 functions as a suppressor of the cell cycle. Moreover, transcription factor enrichment analysis detected the E2F family of transcription factors significantly associated with CBX7 negatively coexpressed genes, consistent with E2F function regulating the cell cycle. Furthermore, we found that loss of CBX7 expression significantly increases genomic instability and tumor mutation burden. Our findings indicate that CBX7 acts as a tumor suppressor in BC through its potential role in the negative regulation of cell proliferation and the maintenance of genome integrity.

The Impact of BMP-4 Tissue Expression on Progression and Survival in Breast Cancer.

Bone morphogenetic protein -4 (BMP-4) plays important role in many aspects of carcinogenesis but is also involved in progression and metastasis of breast cancer where its precise role is yet to be elucidated. Since the majority of studies related to BMP-4 expression in breast cancer were conducted on cell lines of mouse models, we aimed to investigate BMP-4 tissue expression in primary human breast cancer and to correlate it with standard pathological factors for breast cancer, progression and survival. We analyzed immunohistochemical expression of BMP-4 in primary breast cancer tissue of 97 patients, correlated it with standard pathological factors for breast cancer and investigated its impact on progression and survival. BMP-4 expression was positive in 74.23% breast cancer tissue specimens. We found that hormone positive breast tumors are more likely to show BMP-4 strong granular staining pattern (p<0.01; p=0.029, respectively). There was significant association between stage group and BMP-4 expression in order that stage III breast cancer group were predominantly BMP-4 positive tumors (p=0.046). Although the most common site of distant metastases in patients with BMP-4 positive tumors were bones, we found no significant association (p>0.05). Patients with BMP-4 positive breast cancer showed longer overall and progression-free survival, but the results did not reach statistical significance (p>0.05). The results of our study in some extent can confirm the current available data and suggest that the role of BMP-4 in breast cancer is ambiguous, acting both as tumor suppressor and tumor promoter in breast cancer. For final elucidation of its impact on survival and progression in breast cancer, multicentric studies on larger sample size are required.

Expression of BRCA1 by immunohistochemistry and its association with ER, PR, Her2neu status in infiltrative ductal carcinoma of breast.

Breast cancer is a heterogeneous disease, which differs in its clinical behaviors and responses to treatment and outcome. The prognosis of breast cancer depends on histopathological parameters and molecular subtypes. Among more than 300 genes, which are involved in the pathogenesis of breast cancer tumor suppressor gene such as BRCA1 is known to play a significant role in hereditary cancers. However, its role in sporadic cases of infiltrating ductal carcinoma is yet to be established. To evaluate the expression of BRCA1 in infiltrative ductal carcinoma and to analyze the association of BRCA1 with histopathological parameters and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor2 (Her2) neu expression. This was a laboratory-based exploratory study in which 56 patients with infiltrative ductal carcinoma who underwent radical mastectomy from October 2019 to July 2021 were included. Patients with chemotherapy and radiotherapy, trucut biopsies, and incomplete patient details were excluded. Immunostaining for BRCA1 was performed. Individual clinicopathological parameters were compared with the BRCA1 mutation. Statistical analysis was done using SPSS 22. A P value of < 0.05 was considered statistically significant. Among 56 cases of IDC, 18 cases (32.1%) showed BRCA1 mutation. BRCA1 mutation was associated with postmenopausal age, larger tumor size, lower tumor grade, and higher tumor staging. When we analyzed the biomarkers with BRCA1 mutation, it showed a negative association with ER, PR, and Her2 neu and a high Ki67 proliferation index. No family history of breast carcinoma was seen in 34/56 patients where history was available. Our study showed BRCA1 mutation in 32.1% and associated with postmenopausal age group, larger tumor size, and higher staging and negative hormonal status of breast carcinoma.

Human Papillomavirus E1 Protein Regulates Gene Expression in Cells Involved in Immune Response.

Human papillomavirus belongs to papovaviridae family papillomavirus A, a spherical deoxyribonucleic acid (DNA) virus, which can cause the proliferation of squamous epithelial cells of human skin or mucous membranes. With the rapid increase in the incidence of condyloma acuminatum among STDs and the increase in diseases caused by HPV infection, HPV infection has seriously endangered human health. In this paper, the in vitro detection of HPV E1 protein was realized using AgNCs-dsDNA. And through the test of this detection method, we calculated that the detection limit of this method is 0.886nM. Compared with other methods for detecting E1 protein in vitro, this method has high sensitivity and simple operation. In addition, the detection method also has good anti-interference and selectivity, and can realize the detection of E1 in serum samples. The transfection efficiency of BLV-miR-B4-3p mimics at different time points was determined by quantitative real-time PCR (qPCR); the transcriptome sequencing of lymphocytes transfected with different concentrations of BLV-miR-B4-3p mimics was performed, and differential gene clustering was performed on the sequencing results. And the BLV-miR-B4-3p target gene prediction and transcriptome analysis results were verified by qPCR. The effects of BLV-miR-B4-3p on the transcriptional levels of immune-related cytokines in human lymphocytes were analyzed. Transcriptome sequencing analysis showed that after BLV-miR-B4-3p entered lymphocytes, a total of 556 differentially expressed genes were obtained. GO enrichment and KEGG analysis results showed that BLV-miR-B4-3p could independently activate influenza. The signaling pathway ultimately affects the body's immune system process, stress response, defense response, immune response, and other biological processes. After BLV-miR-B4-3p enters lymphocytes, it will lead to abnormal lymphocyte immune function, including the mRNA expression of TNF-α in Th1 cytokines which was significantly increased (P < 0.05), and the expression of IL-10 in Th2 cytokines was significantly increased (P < 0.05). The mRNA expression was significantly decreased (P < 0.05), and the mRNA expression of IL-27 was significantly increased (P < 0.001), which did not affect the mRNA expression of lymphocyte proliferation and activation-related regulators. The tumor suppressor breast cancer 1 (BRCA1) and antimicrobial peptide CAMP were significantly increased, and decreased (P < 0.001), and the expression of pro-apoptotic factor Caspase9 showed a significant downward trend (P < 0.05).

Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation.

Coiled-coil domain containing 3 (CCDC3) was previously shown to regulate liver lipid metabolism as a secretory protein. Here, we report an unexpected intracellular role of CCDC3 as a tumor suppressor in breast cancer (BrC). Bioinformatics datasets analysis showed that CCDC3 is under-expressed in BrCs, while its higher levels are correlated with higher overall survival and lower relapse of cancer patients, and CCDC3 is positively correlated with p53 and its target genes. Ectopic CCDC3 markedly suppressed proliferation, colony formation, and xenograft tumor growth by augmenting p53 activity in BrC cells. Depletion of endogenous CCDC3 by CRISPR-Cas9 increased proliferation and drug resistance of BrC cells by alleviating 5-Fluorouracil (5-FU)-induced p53 level and activity. Mechanistically, CCDC3 bound to the C-termini of p53 and MDM2, consequently stabilizing p53 in the nucleus and impairing MDM2 recruitment of p53 to the 26S proteosome without inhibiting p53 ubiquitination. p53 induced CCDC3 expression by binding to its promoter in BrC cells. Our results unveil a unique mechanism underlying CCDC3 activation of p53 in a positive feedback fashion to suppress BrC growth.

The Prognostic Value of ADAMTS8 and Its Role as a Tumor Suppressor in Breast Cancer

A disintegrin-like and metalloprotease with therombospondin type1 motif 8 (ADAMTS8) plays an important role in many malignancies. However, the clinical and biological significance of ADAMTS8 in breast cancer remain unknown. In this study, the clinical data from 1066 breast cancer patients were analyzed by The Cancer Genome Atlas (TCGA) database, and were analyzed using the correlation between ADAMTS8 expression and the clinicopathological features and prognoses. The CCK-8 assay, clone formation assay, flow cytometry and Transwell assay were used to characterize the effects of ADAMTS8 on proliferation, migration and invasion of breast cancer cells. Gene set enrichment analysis (GSEA) and western blotting were used to identify the potential molecular mechanism on how ADAMTS8 exert its biological function. ADAMTS8 overexpression correlated longer overall survival (OS) and progression-free survival (PFS). ADAMTS8 was considered as an independent prognostic factor for OS. ADAMTS8 overexpression inhibited breast cancer cell proliferation, migration and invasion in vitro, and induced G2/M cell cycle arrest. ADAMTS8 was also involved in cell cycle regulation and was associated with the EGFR/Akt signaling pathway. ADAMTS8 knockdown showed the reverse effect. Together, the results showed that ADAMTS8 functioned as a tumor suppressor gene (TGS) and could be a prognostic biomarker for breast cancer.

LACTB suppresses migration and invasion of glioblastoma via downregulating RHOC/Cofilin signaling pathway

Glioblastoma (GBM) is the most malignant tumor in human brain. High invasiveness of this tumor is the main reason causing treatment failure and recurrence. Previous study has found that LACTB is a novel tumor suppressor in breast cancer. Moreover, the function of LACTB in other tumors and mechanisms involving LACTB were also reported. However, the role and relevant mechanisms of LACTB in GBM invasion remains to be revealed. Our aim is to investigate the role LACTB in GBM migration and invasion. We found that LACTB was downregulated in gliomas compared to normal brain tissues. Overexpression of LACTB suppressed migration and invasion of LN229 and U87 cell lines. Mechanistically, LACTB overexpression downregulated the mesenchymal markers. Moreover, LACTB overexpression downregulated the expression of RHOC and inhibited RHOC/Cofilin signaling pathway. The study suggests that LACTB suppresses migration and invasion of GBM cell lines via downregulating RHOC/Cofilin signaling pathway. These findings suggest that LACTB may be a potential treatment target of GBM.

Functional Characterization of lncRNA152 as an Angiogenesis-Inhibiting Tumor Suppressor in Triple-Negative Breast Cancers.

This study identifies lncRNA152 as an angiogenesis-inhibiting tumor suppressor that attenuates the aggressive cancer-related phenotypes found in TNBC by upregulating the expression of the tumor suppressor RBM47. As such, lncRNA152 may serve as a biomarker to track aggressiveness of breast cancer, as well as therapeutic target for treating TNBC.

MiR-1294 inhibits the progression of breast cancer via regulating ERK signaling

Breast cancer (BC) is the most diagnosed carcinoma in women worldwide, which is characterized with a high incidence rate and poor prognosis. MicroRNAs (miRNAs) are promising biomarkers for early detection of BC. In this study, we demonstrated that MiR1294 was downregulated in BC. Moreover, we revealed that MiRNA1294 significantly suppressed cell proliferation, migration and invasion. Animal models revealed that MiRNA1294 reduced tumor formation. In addition, we found that ERK signaling was involved in the regulatory role of MiRNA1294 in BC. In conclusion, MiRNA1294 acted as a tumor suppressor in BC, which might serve as a potential target for the development of anti-neoplastic therapies in BC.

Особливості експресії молекул клітинної адгезії Е-кадгерину в різних молекулярних підтипах інвазивного протокового раку грудної залози

The purpose of the study was to determine the role of E-cadherin in the development and progression of molecular subtypes of invasive ductal breast cancer by assessing the expression of E-cadherin in various clinical and pathological prognostic parameters. Materials and methods. We demonstrated a comprehensive morphological, including immunohistochemical study of 193 cases of invasive ductal breast cancer with the molecular phenotype definition. General histological processing of samples was performed according to standard methods. Immunohistochemical studies for E-cadherin, ER, PR, c-erbB2, Ki-67 were performed according to standardized analytically validated protocols with the necessary controls. The grade of malignancy was determined according to the modified scheme of P. Scarff, H. Bloom and W. Richardson. E-cadherin expression level was quantified in 86 observations using the Qureshi counting system. Comparison of E-cadherin expression in different clinical and pathological parameters was evaluated using Pearson's test χ2. For all types of analysis, differences were considered significant at p &lt;0.05. Results and discussion. E-cadherin expression in ductal breast cancer tissue is significantly lower in cases with lymph node metastases than without metastatic lymph node involvement (χ2 = 4.55, p = 0.031). Low expression of E-cadherin or its absence was associated with pT3 tumors, clinical stage 3, with G2 and G3 malignancies. Loss of E-cadherin expression has an unfavorable prognostic value. E-cadherin expression is associated with the molecular type of invasive breast ductal carcinoma. High E-cadherin expression was common in ER-positive tumors of the luminal A phenotype and was determined in patients of both premenopausal and postmenopausal age, suggesting that ER-positive expression may be involved in the regulation of E-cadherin expression. Low tumor activity of cells of invasive ductal breast cancer of the luminal subtype is accompanied by an increase in the adhesive properties of these cells due to the high level of expression of E-cadherin. E-cadherin is considered an independent marker of triple-negative breast cancer and is characterized by an unfavorable prognosis and short life expectancy. Triple-negative cancer was associated with a significant predominance of patients with low and negative E-cadherin expression (p = 0.011). Conclusion. Thus, E-cadherin is a potent tumor suppressor of breast cancer. According to this role in the progression of breast cancer, it was found that partial or complete loss of E-cadherin expression correlates with an unfavorable prognosis in patients

Withaferin A mediated changes of miRNA expression in breast cancer-derived mammospheres.

Breast cancer is a heterogeneous disease consisting of atypical cell populations that share stem cell-like characteristics associated with therapeutic resistance, disease relapse, and poor clinical outcome. MicroRNAs (miRNA),and small noncoding RNA, are pivotal in the regulation of self-renewal, stemness, and cellular differentiation. Withaferin A (WA), a steroidal lactone, is a major bioactive constituent of Withania somnifera (Solanaceae) known for its anticancer properties. In this study, the effect of WA on modulation of miRNA expression in breast cancer-derived mammosphere was assessed utilizing small RNA sequencing. Treatment with WA inhibited MCF-7 and T47D cells derived mammosphere formation with a significant decrease in CD44, EpCAM, Nanog, OCT4, and SOX2 as markers of self-renewal and stemness. Small RNA sequencing demonstrated a total of 395 differentially expressed miRNAs (DEMs) including 194 upregulated and 201 downregulated miRNAs in WA-treatedMCF-7 mammospheres. Bioinformatics analysis utilizing theKEGG pathway, Gene Ontology enrichment, protein-protein, and miRNA-mRNA interaction network identified altered expression in a few hub genes viz.AKT1, PTEN, MYC, CCND1,VEGFA,NOTCH1, andIGFR1associated with DEMs in WA-treatedmammospheres. Further quantitativeRT-PCR analysis validated the expression of DEMs including miR-549a-5p, miR-1247-5p, miR-124-5p, miR-137-5p, miR-34a-5p, miR-146a-5p, miR-99a-5p, miR-181a-5p, let-7c-5p, and let-7a-5p. In particular, let-7c-5p is designated as a tumor suppressor in breast cancer. An increase in miR-let-7c-5p expression was noted after WA treatment, with a simultaneous decrease in CCND1 and c-MYC at mRNA and protein levels. Taken together, our study demonstrated WA-mediated miRNA expression, in particular, upregulation of miR-let-7c-5p, leads to the inhibition of breast cancer cells derived mammospheres.

Abstract 3463: Nischarin agonist rilmenidine inhibits pancreatic ductal adenocarcinoma cell migration and invasion

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal malignancy due to the lack of early diagnosis and limited response to all treatment modalities. Early metastatic dissemination, rich desmoplastic stroma and immunosuppressive infiltrate are some of the features contributing to the poor prognosis of PDAC patients (5-year survival rate of less than 10%). Despite scientific progress in the development of new therapeutic regimes, PDAC patients in low- and middle-income countries have restricted access to high-cost innovative drugs. Recently, attention has been given to the concept of drug repurposing that could meet the need for novel but affordable and widely accessible therapies. Imidazoline receptor 1 Nischarin (NISCH, IR1, IRAS) is an integrin α5-interacting protein that acts as a tumor suppressor in breast cancer through modulation of cancer cell motility and survival. Importantly, NISCH has several clinically approved agonists that are used for the treatment of hypertension and are shown to modulate autophagy and reduce inflammation and fibrosis, which makes NISCH a potentially good therapeutic target for defying PDAC progression. Based on our GSEA analysis of NISCH expression in PDAC patient samples, NISCH was predicted to have an effect on cancer cell focal adhesion assembly and cytoskeletal organization. Therefore, we examined the effects of NISCH agonists on PDAC cells fitness in vitro. A panel of PDAC cell lines was tested in MTT assay to determine the effects of NISCH agonists rilmenidine, clonidine and moxonidine on cell viability. Flow cytometry, western blot and immunofluorescence were used to examine the effects of NISCH agonists on PDAC cell metabolism, migration and cytoskeletal organization. Tg(fli1:EGFP) zebrafish model was used to examine the effects of NISCH agonists on PDAC cell growth and invasion. We found that NISCH was expressed in PDAC cell lines, and that out of the three tested agonists, rilmenidine most potently inhibited cancer cell viability. Treatment with rilmenidine significantly reduced PANC-1, MIA PaCa-2 and BxPC-3 cell attachment to extracellular matrix (collagen type I and fibronectin) and migratory potential in wound healing and transwell assays. Furthermore, treatment with rilmenidine altered the organization of actin cytoskeleton and focal adhesion assembly, potentially through the reduction of intracellular reactive oxygen species (ROS) levels. Importantly, treatment with rilmenidine inhibited invasion of PANC-1 cells in Tg(fli1:EGFP) zebrafish model. With these antimigratory and potentially antimetastatic effects of rilmenidine, our study lays the ground for a more extensive examination of the biological role of NISCH in PDAC progression and implies that its agonists may be good candidates for drug repurposing in this type of cancer. Citation Format: Marijana Pavlovic, Marija Ostojic, Kristina Zivic, Aleksandar Pavic, Tatjana Srdic-Rajic, Jelena Grahovac. Nischarin agonist rilmenidine inhibits pancreatic ductal adenocarcinoma cell migration and invasion [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 3463.

Abstract 856: Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation

Abstract Coiled-coil domain containing 3 (CCDC3) was previously shown to regulate liver lipid metabolism as a secretory protein. Our recent studies revealed an intracellular role of CCDC3 as a tumor suppressor in breast cancer (BrC). Bioinformatics datasets analysis showed that CCDC3 is under-expressed in BrCs, while its higher levels are correlated with higher overall survival and lower relapse of cancer patients. CCDC3 is positively correlated with p53 and its target genes. Ectopic CCDC3 markedly suppressed proliferation, colony formation, and xenograft tumor growth by augmenting p53 activity in BrC cells. In contrast, knockdown of endogenous CCDC3 using CRISPR led to reduction of p53 level and activity, consequently promoting the proliferation of BrC cells. Mechanistically, CCDC3 bound to the C-termini of p53 and MDM2, consequently stabilizing p53 in the nucleus and impairing MDM2 recruitment of p53 to the 26S proteosome without inhibiting p53 ubiquitination. Also, knockdown of CCDC3 caused the resistance of BrC cells to 5-FU to some degrees by alleviating p53 response to this drug. p53 induced CCDC3 expression by binding to its promoter specifically in BrC cells. Our results unveil a unique mechanism underlying CCDC3 activation of p53 in a positive feedback fashion to suppress BrC growth and suggest that CCDC3 deficiency could be a factor for drug resistance of BrCs. Citation Format: Hyemin Lee, Caiyue Li, Ji Hoon Jung, Yiwei Zhang, Jieqiong Wang, Chang Liu, Allyson M. Segall, Roger L. Sheffmaker, Shelya X. Zeng, Hua Lu. Coiled-coil domain containing 3 suppresses breast cancer growth by protecting p53 from proteasome-mediated degradation [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 856.

The expression and the tumor suppressor role of CLDN6 in colon cancer.

As a member of the tight junction family, CLDN6 is a tumor suppressor in breast cancer, but its role in colon cancer is unknown. In this research, we aimed at revealing the function of CLDN6 in colon cancer. We found that colon cancer tissues lowly expressed CLDN6, and the expression of CLDN6 was negatively correlated with lymph node metastasis. Similarly, CLDN6 was lowly expressed in the colon cancer cell line SW1116, and overexpression of CLDN6 inhibited cell proliferation in vitro and in vivo. Consistently, the migration and invasion abilities of cells were significantly inhibited after CLDN6 overexpression. In addition, we demonstrated that CLDN6 may inhibit the migration and invasion abilities by activating the TYK2/STAT3 pathway. Therefore, our data indicated that CLDN6 acted as a tumor suppressor and had the potential to be regarded as a biomarker for the progression of colon cancer.

RhoBTB3 Regulates Proliferation and Invasion of Breast Cancer Cells via Col1a1.

Breast cancer is the leading cause of cancer-related death in women worldwide, despite medical and technological advancements. The RhoBTB family consists of three isoforms: RhoBTB1, RhoBTB2, and RhoBTB3. RhoBTB1 and RhoBTB2 have been proposed as tumor suppressors in breast cancer. However, the roles of RhoBTB3 proteins are unknown in breast cancer. Bioinformatics analysis, including Oncomine, cBioportal, was used to evaluate the potential functions and prognostic values of RhoBTB3 and Col1a1 in breast cancer. qRT-PCR analysis and immunoblotting assay were performed to investigate relevant expression. Functional experiments including proliferation assay, invasion assay, and flow cytometry assay were conducted to determine the role of RhoBTB3 and Col1a1 in breast cancer cells. RhoBTB3 mRNA levels were significantly up-regulated in breast cancer tissues as compared to in adjacent normal tissues. Moreover, RhoBTB3 expression was found to be associated with Col1a1 expression. Decreasing RhoBTB3 expression may lead to decreases in the proliferative and invasive properties of breast cancer cells. Further, Col1a1 knockdown in breast cancer cells limited the proliferative and invasive ability of cancer cells. Knockdown of RhoBTB3 may exert inhibit the proliferation, migration, and metastasis of breast cancer cells by repressing the expression of Col1a1, providing a novel therapeutic strategy for treating breast cancer.

Retracted] MicroRNA‑133a acts as a tumour suppressor in breast cancer through targeting LASP1

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that the western blotting assay data shown in Figs.5B, 5E, 6C and 7A were strikingly similar to data appearing in different form in other articles by different authors. Owing to the fact that the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [the original article was published in Oncology Reports 39: 473‑482, 2018; DOI: 10.3892/or.2017.6114].

DMT1‐mediated endosome‐mitochondria interactions regulates iron homeostasis and mitochondrial metabolism

Mitochondria‐early endosome (EE) interactions have been shown to facilitate the translocation of iron into mitochondria. Here we show that Divalent Metal Transporter 1 (DMT1) modulates iron exit from endosomes and transport into mitochondria via regulation of EE‐mitochondria interactions. In cancer cells, mitochondria are the ultimate cellular iron sink, where iron can be either stored or used for example to shift cellular metabolism towards glycolysis (Warburg effect), a key adaptive mechanism of cancer cells. Moreover, a gene signature associated with reduced intracellular iron content, including low transferrin receptor (TfR) (anti‐import) and high ferroportin (FPN) (pro‐export) expression levels, has been related to favorable breast cancer prognosis. Similarly, reduced DMT1 expression associates with improved breast cancer patient survival. We evaluated the role of DMT1 in two distinct breast cancer cell lines: estrogen receptor positive T47D and triple‐negative MDAMB231. In both cell lines, we demonstrate colocalization between EE, DMT1 and mitochondria. Interestingly, DMT1 is localized to the surface contact area between endosomes and mitochondria. To demonstrate that DMT1 plays a role in endosome‐mitochondria interactions and Mitochondrial Iron Translocation (MIT), we have generated MDAMB231 as well as T47D CRISPR/Cas9 based DMT1 knockout (KO) stable cell lines. Several lines of evidence show that DMT1 regulates MIT and labile iron pool (LIP) levels via modulation of EE‐mitochondria interactions in MDAMB231 cells. MIT decrease via DMT1 silencing was partially rescued by re‐expression of DMT1 in MDAMB231, but not in T47D cells. MDAMB231 DMT1 KO cells showed increased Ferro‐Orange staining, indicating higher LIP levels, as well as decreased TfR and increased FPN protein levels. Importantly, DMT1 silencing significantly reduced EE‐mitochondria interactions and EE speed in MDAMB231 but not in T47D. Thus, DMT1 regulates MIT and LIP levels via EE‐mitochondria interactions in MDAMB231. These results are in agreement with previous results showing that MDAMB231 display a delay in iron release in comparison to T47D, making them more sensitive to disruptions in MIT. Since mitophagy has been shown to act as a tumor suppressor in breast cancer, we tested whether it could be modulated by DMT1‐mediated MIT. We found that DMT1 silencing increases mitochondrial ferritin, global autophagy marker LC3B and PINK1/Parkin‐dependent mitophagy markers in MDAMB231; levels of all proteins evaluated were rescued to basal levels upon re‐expression of DMT1 in DMT KO cells. Moreover, DMT1 silencing decreases Tom 20 (outer mitochondrial membrane marker) with PMPCB, a known DMT1 interactor that is required for PINK1 turnover. Concurring with the role of DMT1 in mitophagy and iron metabolism, both mitochondrial metabolism and invasive cell migration are significantly impaired by DMT1 silencing and are partially rescued by re‐expression of DMT1. Overall, our results implicate DMT1 in the regulation of EE dynamics and EE‐mitochondria interactions to support higher MIT/lower LIP levels, which are necessary for sustaining mitochondrial bioenergetics and invasive cell migration. Thus, we propose DMT1 as a key player associated with aggressive phenotypes in breast cancer

Disruption of ZNF334 promotes triple-negative breast carcinoma malignancy through the SFRP1/ Wnt/β-catenin signaling axis.

Zinc-finger proteins (ZNFs) constitute the largest transcription factor family in the human genome. The family functions in many important biological processes involved in tumorigenesis. In our research, we identified ZNF334 as a novel tumor suppressor of triple-negative breast cancer (TNBC). ZNF334 expression was usually reduced in breast cancerv (BrCa) tissues and TNBC cell lines MDA-MB-231 (MB231) and YCCB1. We observed that promoter hypermethylation of ZNF334 was common in BrCa cell lines and tissues, which was likely responsible for its reduced expression. Ectopic expression of ZNF334 in TNBC cell lines MB231 and YCCB1 could suppress their growth and metastatic capacity both in vitro and in vivo, and as well induce cell cycle arrest at S phase and cell apoptosis. Moreover, re-expression of ZNF334 in TNBC cell lines could rescue Epithelial-Mesenchymal Transition (EMT) process and restrain stemness, due to up-regulation of SFRP1, which is an antagonist of Wnt/β-catenin signaling. In conclusion, we verified that ZNF334 had a suppressive function of TNBC cell lines by targeting the SFRP1/Wnt/β-catenin signaling axis, which might have the potentials to become a new biomarker for diagnosis and treatment of TNBC patients.

Is mir125-a rs12976445 a significant predictor of the development of breast cancer in women?

Cancer is one of the main causes of mortality worldwide and the cancer deaths figure is estimated to reach 11 million by 2030 (Momenimovahed and Salehiniya, 2019). Among the cancers, breast cancer is the most common malignancy in women worldwide affecting more than 1 million women annually (Stuckey, 2011; Ghoncheh, et al., 2016). Breast cancer incidence varies widely, ranging from 27/100,0002 (Central-East Asia and Africa) to 85-94/100,0002 (Australia, North America and Western Europe) indicating that the environmental and genetic factors play significant role in incidence of breast cancer occurrence worldwide (Sancho-Garnier and Colonna, 2019). Considering the development and pathology of breast cancer, it is a highly heterogeneous cancer in its pathological characteristics, some cases showing slow growth with excellent prognosis, while others being aggressive tumors (Tao, et al., 2015). Despite many studies carried out to investigate the etiology of breast cancer, much of the etiology of this disease is unknown, however, many gene polymorphisms of breast cancer have been described as possible neoplasm etiologic factors (Bugano et al., 2008).MicroRNAs (miRNAs) have been reported to have a pivotal role in gene regulation and the control of cancer-related mechanisms such as apoptosis and metastasis. miRNAs are short non-coding RNAs that are involved in post-transcriptional regulation of gene expression. miRNAs are transcribed by RNA polymerase II. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce pre-miRNA, which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA. The mature miRNA is incorporated into a RNA-induced silencing complex, which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. Studies have shown that the miR-125 family acts as a tumor suppressor in breast cancer and inhibits ERBB2, ERBB3 and other target genes at post-transcriptional level. The miR-125 family has three homologues, hsa-miR-125a, hsa-miR-125b-1 and hsa-miR-125b-2 located at (19q.13.41), (11q.23) and (21q.21), respectively. Research shows ERBB2, HUR, ROCK-1, KLF13 and ARID3 genes are controlled by miR-125a. However, increased expression level of the genes is related to decreased expression of miR-125a, in breast cancer. Single nucleotide polymorphisms (SNP) of the miRNA encoding genes are believed to be involved in cancer development (Bahreini et al., 2020). Single nucleotide polymorphisms such as rs143525273, rs12975333, rs10404453 and rs12976445 are effective in miR-125a expression. Due to the increasing incidence of breast cancer and important role of miR-125a rs12976445 in the disease many studies have cited this single nucleotide polymorphism (Tang et al., 2015; Tang et al., 2019; Duna et al., 2007; Inoue et al., 2014; Deng et al., 2017; Bahreini et al., 2021).In this study, blood samples were prepared from two groups: patients with breast cancern (approved by an oncologist) (n=51) and control healthy women (n=50) after obtaining written informed consent form. PCR-RFLP technique was used to determine miR-125a genotype. The data were analyzed using Chi-Square.Our findings indicated that there was significant difference regarding rs12976445 genotype distribution between the control group and patients with breast cancer indicating that rs12976445 might be a predictor of the development of breast cancer in women.