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Divergent trends of breast cancer incidence by subtype have been reported in the United States and elsewhere; however, it remains unknown whether this trend has continued until the era of the COVID-19 pandemic. Using high-quality population-based cancer registry data, representing 83% of the US population, this study examined breast cancer incidence rates by estrogen receptor (ER) status in women aged 20-84 years from 2004 to 2020. The incidence rate of ER-positive cancer increased by 1.75% per year from 2004 to 2009 (95% confidence interval [CI] = 1.26%-3.15%) and has slowed to a 0.87% annual increase (95% CI = 0.41%-1.03%) from 2009 to 2019, followed by a 10.2% reduction from 2019 to 2020. Trends were generally similar across race and ethnicity, although young women (20-49 years), Asian or Pacific Islander, and Hispanic women experienced steady increases until 2019. The incidence rate of ER-negative cancer decreased by 3.13% annually (95% CI = -4.2% to -2.55%) from 2004 to 2012, and the decrease stabilized from 2012 to 2019 (annual percent change: 0.55%; 95% CI = -1.30% to 0.92%), followed by a 6.0% reduction from 2019 to 2020, with trends generally consistent by age and across racial and ethnic groups. The stabilization of the steep decline in ER-negative cancer suggests a departure from the encouraging trajectories projected in earlier studies. Coupled with the deceleration in the rise of ER-positive cancer, the latest trend signals a potential stabilization in the previous rise of the proportional burden of ER-positive cancer. Understanding the impact of the pandemic on each subtype of breast cancer individually may provide a more comprehensive insight into its long-term sequelae on survival and mortality., (© 2024 UICC.)

Human epithelial growth factor receptor 2 (HER2)-targeted therapies are effective in patients with HER2-positive breast cancer. Recent advances have shown that HER2-targeted therapies can also be of benefit when treating tumors expressing low levels of HER2, highlighting the importance of identifying the HER2-low subgroup. This clinical trend has opened new therapeutic avenues for patients who were previously ineligible for HER2-targeted therapies. Thus, the development of new diagnostic methods for real-time HER2 profiling is crucial for accurately tailoring the treatment for these patients. We hypothesized that tumor-derived extracellular vesicles (TEVs) could reflect the HER2 profiles of primary tumors and potentially serve as diagnostic tools for HER2 status. This approach was validated using six breast cancer cell lines, which confirmed that the TEVs accurately reflected the HER2 profiles of the tumor cells. TEVs were isolated using an immunoaffinity method, and copy number variation (CNV) in the ERBB2/EIF2C ratio was assessed using droplet digital PCR of DNA from these vesicles. Clinical validation using plasma samples from 33 breast cancer patients further reinforced the diagnostic potential of our method. Pearson's correlation coefficient analysis of the flow cytometry results demonstrated that TEVs reflected HER2 expression in primary cells. To distinguish between HER2-negative and HER2-low patients, the area under the curve (AUC) of the ROC curve in our method was 0.796, with a sensitivity of 53.8% and a specificity of 100%. These findings suggest the clinical utility of extracellular vesicles derived from plasma and emphasize the need for further research to distinguish HER2-negative from HER2-low patients., (© 2024 The Author(s). Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Breast cancer is the major cause of cancer-related mortality and frequent malignancies among women worldwide. The TRIM (Tripartite Motif) protein family is a broad and diverse set of proteins that contain a conserved structural motif known as the tripartite motif, which comprises of three different domains, B-box domain, Coiled-coil domain and RBR (Ring-finger, B-box, and coiled-coil) domain. TRIM proteins are involved in regulating cancer growth and metastasis. However, TRIM proteins are still unexplored in cancer cell regulation. In this study, by using a cancer database expression of all TRIM proteins was determined in breast cancer. Out of 77 TRIM genes, 16 genes were upregulated in breast cancer. Here, the upregulated TRIM26 gene's role is not yet explored in breast cancer. Indeed, TRIM26 is upregulated in 21 cancer types out of 33 cancer types. To investigate the role of TRIM26 in breast cancer, siRNA-mediated gene silencing was carried out in MCF-7 and MDA-MB 231 breast cancer cells. Reduced expression of TRIM 26 decreased cancer cell proliferation, migration and invasion with simultaneous reduction of various proliferative, cell cycle and mesenchymal markers and upregulation of epithelial markers. Further, docking studies found potential novel plant metabolites. Thus, targeting TRIM26 may provide a novel therapeutic approach for breast cancer treatment., (© 2024 Wiley Periodicals LLC.)

Background: Radiomics has been extensively applied in predicting Ki-67 in breast cancer (BC). However, this is often confined to the exploration of a single sequence, without considering the varying sensitivity and specificity among different sequences., Purpose: To develop a nomogram based on dual-sequence MRI derived radiomic features combined with clinical characteristics for assessing Ki-67 expression in BC., Study Type: Retrospective., Population: 227 females (average age, 51 years) with 233 lesions and pathologically confirmed BC, which were divided into the training set (n = 163) and test set (n = 70)., Field Strength/sequence: 3.0-T, T1-weighted dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC) maps from diffusion-weighted MRI (EPI sequence)., Assessment: The regions of interest were manually delineated on ADC and DCE-MRI sequences. Three radiomics models of ADC, DCE-MRI, and dsMRI (combined ADC and DCE-MRI sequences) were constructed by logistic regression and the radiomics score (Radscore) of the best model was calculated. The correlation between Ki-67 expression and clinical characteristics such as receptor status, axillary lymph node (ALN) metastasis status, ADC value, and time signal intensity curve was analyzed, and the clinical model was established. The Radscore was combined with clinical predictors to construct a nomogram., Statistical Tests: The independent sample t-test, Mann-Whitney U test, Chi-squared test, Interclass correlation coefficients (ICCs), single factor analysis, least absolute shrinkage and selection operator (LASSO), logistic regression, receiver operating characteristics, Delong test, Hosmer&#95;Lemeshow test, calibration curve, decision curve. A P-value <0.05 was considered statistically significant., Results: In the test set, the prediction efficiency of the dsMRI model (AUC = 0.862) was higher than ADC model (AUC = 0.797) and DCE-MRI model (AUC = 0.755). With the inclusion of estrogen receptor (ER) and ALN metastasis, the nomogram displayed quality improvement (AUC = 0.876), which was superior to the clinical model (AUC = 0.787) and radiomics model., Data Conclusion: The nomogram based on dsMRI radiomic features and clinical characteristics may be able to assess Ki-67 expression in BC., Level of Evidence: 3 TECHNICAL EFFICACY: Stage 3., (© 2023 International Society for Magnetic Resonance in Medicine.)

LncRNAs play various effects, mostly by sponging with miRNAs. Based on public databases integrating bioinformatics analyses and further validation in breast cancer (BC) tissue and cell lines, the effect of lncRNA AFAP1-AS1 on breast cancer cell proliferation and migration was verified. It might work via the miR-21/PTEN axis. The expression of AFAP1-AS1, which was significantly upregulated in BC tissues and cell lines, was correlated with old age and lymph node metastasis of patients with BC. Knockdown of AFAP1-AS1 inhibited the proliferation and migration of BC cells in vitro and in vivo. And downregulated miR-21 expression and upregulated PTEN expression additionally. Mechanistically, the knockdown of lncRNA AFAP1-AS1 upregulated PTEN expression and consequently attenuated miR-21-mediated enhanced BC cell proliferation and migration. LncRNA AFAP1-AS1 is a potential prognostic biomarker for BC patients., (© 2024 The Author(s). Journal of Cellular Physiology published by Wiley Periodicals LLC.)

Introduction: Trichorhinophalangeal syndrome type 1 (TRPS1) has emerged as a reliable immunohistochemistry (IHC) marker for identifying breast origin in metastatic carcinomas. This study investigates the utility of TRPS1 IHC in non-breast cytology specimens., Materials and Methods: A retrospective search of our pathology database for the year 2021 identified fluids (pleural and peritoneal) and liver, lung and bone fine needle aspirations (FNAs) with surgical follow-up confirming non-breast metastatic carcinomas. Cell blocks from cases with sufficient neoplastic cells underwent immunostaining using a rabbit polyclonal antibody against human TRPS1. Cases lacking tumor on deeper levels after the original work-up were excluded from the study. Two pathologists independently interpreted the TRPS1 staining., Results: Of 136 cases assessed, 31 (22.79%) exhibited positive TRPS1 staining, while 105 (77.21%) were nonreactive. Positivity rates were observed in tumors of Mullerian cell origin, gastrointestinal tract (GIT), and lung origin at 28.85%, 25%, and 21.57%, respectively. Of the tumors of Mullerian cell origin 10 (66.67%) were serous carcinomas, 4 (26.67%) were endometrioid carcinomas, and one (6.67%) was a clear cell carcinoma. Lung tumors comprised seven (63.64%) squamous cell carcinomas and four (36.36%) adenocarcinomas, while the gastrointestinal tumors consisted of 14 (80%) adenocarcinomas and one (20%) squamous cell carcinoma., Conclusions: Although recognized as a sensitive marker for mammary carcinomas, TRPS1 immunostaining was also detected in Mullerian, lung, and GIT carcinomas. This highlights the significance of being cautious when depending solely on TRPS1 immunostaining to distinguish metastatic breast tumors., (© 2024 Wiley Periodicals LLC.)

Background: Approximately, 55% of breast carcinomas are reported to be HER-2 low breast carcinomas. Trastuzumab-Deruxtecan is a new FDA-approved targeted therapy for HER-2 low metastatic breast carcinomas, making it essential that all efforts are made to identify these tumors in specimens submitted for pathologic examination. Cytology specimens are often the first and only modality of this assessment due to the ease of specimen procurement. This study aimed to determine the variability in HER-2 immunostaining interpretation among observers using cytologic specimens from metastatic sites., Design: A pathology database search was made to identify metastatic breast carcinoma reported in cytology specimens. A manual search was then done to identify cases of HER-2 low category, H&E cell block and HER-2 neu immunostain slides were retrieved for a total of 50 cases. Reviewer #1 and #2 independently interpreted HER-2 immunostain of all 50 cases. Only discordant cases were sent for reviewer-3 interpretation. All three were blinded by the metastatic site, and original HER-2 interpretation., Results: Of 50 cases, 11 cases (22%) were reported as concordant scores between reviewer #1 and reviewer #2 but had a discordant original IHC report. Additionally, 4 cases (8%) had discordant reporting of HER2 IHC stain between reviewer #1 and reviewer #2 making a total of 15 cases (30%) with overall discordant results., Conclusion: This study highlights the interobserver variability of HER-2 immunostain interpretation for HER-2 low category of breast carcinomas. We recommend the need for more robust laboratory techniques including molecular for uniform identification of these unique targetable metastatic breast carcinoma groups., (© 2024 Wiley Periodicals LLC.)

Tilorone dihydrochloride (tilorone) is an orally active interferon inducer with anticancer effects. The present study aimed to evaluate the anticancer effects of tilorone in breast cancer. MTT assay was done to measure the proliferation of MCF-7 and MDA-MB-231 breast cancer cells after treatment with tilorone. Mammary carcinogenesis was induced by subcutaneous injection (35 mg/kg, 0.5 mL) of dimethylbenz[a]anthracene (DMBA) in mammary pads of Sprague Dawley (SD) rats. Tumors were allowed to grow for 16 weeks till their sizes reached to 550-700 mm 3 , and then treated with 10 and 20 mg/kg of tilorone and standard drug doxorubicin (4 mg/kg) twice a week for 3 weeks. Normal and disease-control animals received normal saline. Tumor volumes and body weights were measured. Tumors were isolated to measure the levels of interferon-β (IFN-β), vascular endothelial growth factor-A (VEGF-A), P53 and inflammatory markers by enzyme-linked immunosorbent assay (ELISA). Serum biochemistry, lipid peroxidation (LPO) and antioxidant enzymes were measured by standard methods. Histopathology and immunohistochemistry (IHC) of P53 was done in tumor sections. Tilorone reduced the proliferation of MCF-7 and MDA-MB-231 cells with IC 50 concentrations at 34.08 µM and 14.27 µM, respectively. Tilorone treatment showed reduced tumor volume, and increased survival with no significant changes in the body weights. Tilorone treatment also decreased levels of inflammatory markers and VEGF-A and increased IFN-β and P53 levels. Further, treatment with tilorone also decreased LPO and increased antioxidants levels. Histopathology of tumor sections showed normalizing morphology of treated animals. IHC of tumor sections showed increased levels of P53. In conclusion, tilorone has potential anticancer effects against breast cancer., (© 2024 Wiley Periodicals LLC.)

HER3 is mutated in ~2%-10% of cancers depending on the cancer type. We found the HER3-V104L mutation to be activating from patient-derived mutations introduced via lentiviral transduction in HER3KO HER2 + HCC1569 breast cancer cells in which endogenous HER3 was eliminated by CRISPR/Cas9. Cells expressing HER3-V104L showed higher p-HER3 and p-ERK1/2 expression versus cells expressing wild-type HER3 or HER3-V104M. Patients whose tumor expressed the HER3 V104L variant had a reduced probability of overall survival compared to patients lacking a HER3 mutation whereas we did not find a statistically significant difference in overall survival of various cancer patients with the HER3 V104M mutation. Our data showed that HER2 inhibitors suppressed cell growth of HCC1569HER3KO cells stably expressing the HER3-V104L mutation. Cancer cell lines (SNU407, UC15 and DV90) with endogenous HER3-V104M mutation showed reduced cell proliferation and p-HER2/p-ERK1/2 expression with HER2 inhibitor treatment. Knock down of HER3 abrogated cell proliferation in the above cell lines which were overall more sensitive to the ERK inhibitor SCH779284 versus PI3K inhibitors. HER3-V104L mutation stabilized HER3 protein expression in COS7 and SNUC5 cells. COS7 cells transiently transfected with the HER3-V104L mutation in the presence of HER binding partners showed higher expression of p-HER3, p-ERK1/2 versus HER3-WT in a NRG-independent manner without any change in AKT signaling. Overall, this study shows the clinical relevance of the HER3 V104L and the V104M mutations and its response to HER2, PI3K and ERK inhibitors., (© 2024 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1-20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR., (© 2024 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

17β-estradiol is a hormone that plays a vital role in human physiology. It acts through estrogen receptors, specifically estrogen receptor α and estrogen receptor β, and its action is determined by the pulsatile secretion in the bloodstream. 17β-estradiol affects cell proliferation, and dysregulation of 17β-estradiol:estrogen receptor α signaling contribute to the development of breast cancer. Previous research on 17β-estradiol:estrogen receptor α signaling has primarily used two-dimensional cell cultures, which do not fully recapitulate the complexity of tumors that exist in a three-dimensional environment and do not consider the pulsatile nature of this hormone. To address these limitations, we studied 17β-estradiol:estrogen receptor α signaling in cell proliferation using both two-dimensional and three-dimensional breast cancer cell culture models under continuous and pulsatile stimulation conditions. Results revealed that breast cancer cells grown in an alginate-based three-dimensional matrix exhibited similar responsiveness to 17β-estradiol compared with cells grown in conventional two-dimensional culture plates. 17β-estradiol induced the expression of proteins containing estrogen response element in the three-dimensional model. The efficacy of the antiestrogen drugs fulvestrant (ICI182,280) and 4OH-tamoxifen was also demonstrated in the three-dimensional model. These results support the use of the three-dimensional culture model for studying tumor response to drugs and provide a more realistic microenvironment for such studies. Furthermore, the study revealed that a brief 5-min exposure to 17β-estradiol triggered a physiological response comparable with continuous hormone exposure, suggesting that the cellular response to 17β-estradiol is more important than the continuous presence of the hormone. In conclusion, the study demonstrates that the alginate-based three-dimensional culture model is suitable for studying the effects of 17β-estradiol and antiestrogen drugs on breast cancer cells, offering a more realistic representation of tumor-microenvironment interactions. The results also highlight the importance of considering the physiological importance of the temporal dynamics in studying 17β-estradiol signaling and cellular responses., (© 2024 Wiley Periodicals LLC.)

This contribution insight on the cytotoxic and anticancer activities and molecular mechanism of phyto-reduced silver nanoparticles (AgNPs) in MCF-7 breast cancer cell lines. A simple, entirely green synthesis process was optimized for the phyto-reduction of AgNP (~12.7 nm) using aqueous leaf extracts of Indigofera heterantha. The structural and vibrational properties of biosynthesized AgNPs were extensively characterized using UV-Vis spectrophotometer, x-ray diffraction (XRD), dynamic light scattering (DLS), and Fourier transform Infrared spectroscopy (FTIR), while their shape and morphology was studied through scanning electron microscopy (SEM). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay indicates concentration dependent inhibition with IC 50 , 27.93 ± 2.10 μg/mL against MCF-7 cells and 294.38 ± 3.87 μg/mL against L929 cells. The manifested anticancer mechanism in MCF-7 cells was extensively studied using Acridine orange/ethidium bromide (AO/EB), 4',6-diamidino-2-phenylindole (DAPI) and Annexin-V/propedium iodide fluorescence microscopic assays. The level of reactive oxygen species (ROS) was measured using DCFH-DA fluorescent spectroscopy. Overall, the results show that AgNPs exhibit cytotoxic and apoptotic effect on breast cancer MCF-7 cells by damaging membrane integrity and nuclear fragmentation due to oxidative stress generated by elevated level of ROS. RESEARCH HIGHLIGHTS: Biomimetic synthesis of nano dimension size silver nanoparticles (AgNPs). Characterization of AgNPs through UV-Vis, DLS, XRD, FTIR, and SEM. Cytotoxic and anticancer effects of the biosynthesized AgNPs in L929 fibroblast cells and MCF7 breast cancer respectively. Determination of morphological, and nuclear changes triggered by AgNPs in MCF 7 breast cancer cells using fluorescent microscopy and flow cytometry. Apoptosis induction by AgNPs in cancer cells through oxidative stress generated by reactive oxygen species (ROS)., (© 2024 Wiley Periodicals LLC.)

Altered energy metabolism is an emerging hallmark of cancer and plays a pivotal in cell survival, proliferation, and biosynthesis. In a rapidly proliferating cancer, energy metabolism acts in synergism with epithelial-to-mesenchymal transition (EMT), enabling cancer stemness, dissemination, and metastasis. In this study, an interconnected functional network governing energy metabolism and EMT signaling pathways was targeted through the concurrent inhibition of IR, ITGB1, and CD36 activity. A novel multicomponent MD simulation approach was employed to portray the simultaneous inhibition of IR, ITGB1, and CD36 by a 2:1 combination of Pimozide and Ponatinib. Further, in-vitro studies revealed the synergistic anticancer efficacy of drugs against monolayer as well as tumor spheroids of breast cancer cell lines (MCF-7 and MDA-MB-231). In addition, the combination therapy exerted approximately 40% of the apoptotic population and more than 1.5- to 3-fold reduction in the expression of ITGB1, IR, p-IR, IRS-1, and p-AKT in MCF-7 and MDA-MB-231 cell lines. Moreover, the reduction in fatty acid uptake, lipid droplet accumulation, cancer stemness, and migration properties were also observed. Thus, targeting IR, ITGB1, and CD36 in the interconnected network with the combination of Pimozide and Ponatinib represents a promising therapeutic approach for breast cancer., (© 2024 Wiley Periodicals LLC.)

Na, K-ATPase interaction (NKAIN) is a transmembrane protein family, which can interact with Na, K-ATPase β1 subunit. NKAIN1 plays an important role in alcohol-dependent diseases such as endometrial and prostate cancers. However, the relationship between NKAIN1 and human breast cancer has not been studied. Hence, this study aimed to explore the relationship between NKAIN1 expression and breast cancer. Data used in this study were mainly from the Cancer Genome Atlas, including differential expression analysis, Kaplan-Meier survival analysis, receiver operating characteristic curve analysis, multiple Cox regression analysis, co-expression gene analysis, and gene set enrichment analysis. Analyses were performed using reverse transcription-quantitative polymerase chain reaction, western blot analysis, and immunohistochemistry on 46 collected samples. The knockdown or overexpression of NKAIN1 in vitro in MCF-7 and MDA-MB-231 cell lines altered the proliferation and migration abilities of tumor cells. In vivo experiments further confirmed that NKAIN1 knockdown effectively inhibited the proliferation and migration of cancer cells. Therefore, our study identified NKAIN1 as an oncogene that is highly expressed in breast cancer tissues. The findings highlight the potential of NKAIN1 as a molecular biomarker of breast cancer., (© 2024 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

BRAWO, a real-world study, assessed the efficacy, quality of life (QoL) and safety of EVE + EXE in postmenopausal women with HR+/HER2- advanced breast cancer (ABC) in routine clinical practice. Postmenopausal women with HR+/HER2-ABC with recurrence or progression after a NSAI were included. Primary Observation parameters included the evaluation of the effectiveness of EVE + EXE. A multivariate-analysis using Cox proportional hazard model was built to identify predictors of progression. Overall, 2100 patients were enrolled (August 2012-December 2017); 2074 were evaluable for efficacy and safety analyses. Majority of patients (60.6%) received EVE + EXE as first (28.7%) or second-line (31.9%) therapy. Visceral metastases were present in 54.1% patients. Median progression-free survival (mPFS) reported as 6.6 months (95%CI: 6.3-7.0). Multivariate-analysis in a subset of patients (n = 1837) found higher body mass index (BMI) and non-visceral metastases to be independent predictors of favorable PFS. Patients with a BMI of 20 to <25 had a mPFS of 6.0 (95%CI: 5.4-6.4) and those with a BMI ≥30 had mPFS of 8.5 (95%CI: 6.9-9.9). 41.2% patients achieved stable disease and 7.3% partial response. No major changes were observed QoL; 86.4% patients received stomatitis prophylaxis and 41.4% experienced EVE related AEs of stomatitis, mainly low grade. AEs occurred in 91.2% of patients, of which stomatitis (42.6%) and fatigue (19.8%) were most frequent. The BRAWO study provides real-world evidence of efficacy and safety of EVE + EXE in patients with HR+, HER2- ABC. A high BMI and the absence of visceral metastases were independent predictors of PFS in this cohort of patients., (© 2024 UICC.)

Breast cancer stem cells (BCSCs) are key players in carcinogenesis and development. Small nucleolar RNAs (snoRNAs) seem to have a crucial influence on regulating stem cell-like properties in various cancers, but the underlying mechanism in breast cancer has not been determined. In this study, we first found that the expression of SNORA51 might be strongly and positively related to BCSCs-like properties. SNORA51 expression was assessed in breast cancer tissues (n = 158 patients) by in situ hybridization. Colony formation, cell counting kit-8, and sphere formation assays were used to detect cell proliferation and self-renewal, respectively. Wound healing and transwell assays were used to detect cell migration. Coimmunoprecipitation and molecular docking were used to determine the underlying mechanism through which SNORA51 regulates BCSCs-like properties. High SNORA51 expression was associated with a worse prognosis, overall survival, and disease-free survival, in 158 breast cancer patients and was also closely related to lymph node status, ER status, the Ki-67 index, histological grade, and TNM stage. Further analysis proved that SNORA51 could enhance and maintain stem cell-like properties, including cell proliferation, self-renewal, and migration, in breast cancer. Moreover, high SNORA51 expression could reduce nucleolar RPL3 expression, induce changes in the expression of NPM1 in the nucleolus and nucleoplasm, and ultimately increase c-MYC expression. Taken together, our findings demonstrated that SNORA51 could enhance BCSCs-like properties via the RPL3/NPM1/c-MYC pathway both in vitro and in vivo. Therefore, SNORA51 might be a significant biomarker and potential therapeutic target and might even provide a new viewpoint on the regulatory mechanism of snoRNAs in breast cancer or other malignant tumors., (© 2024 Wiley Periodicals LLC.)

Medium-chain fatty acids (MCFAs) have 6-12 carbon atoms and are instantly absorbed into the bloodstream before traveling to the portal vein and the liver, where they are immediately used for energy and may have antitumor effects. Its role in breast cancer is poorly understood. To investigate the apoptosis-inducing effect of MCFAs in breast cancer cells, cell viability assay, colony formation assay, cell migration assay, cell invasion assay, nuclear morphology, cell cycle assay, intracellular reactive oxygen species (ROS), matrix metalloproteinase (MMP), apoptosis, RT-qPCR analysis, and Western blot analysis were performed. In the present study, MCFA treatments reduced proliferative capability, increased ROS level, increased the depletion of MMP, induced G0/G1 and S phase cell cycle arrest, and late apoptosis of breast cancer cells in an effective concentration. Besides, MCFA treatment contributed to the upregulation of proapoptotic protein (BAK) and caspase-3, and the downregulation of antiapoptotic protein (Bcl-2). Mechanistically, phosphorylation levels of EGFR, Akt, and mTOR were significantly reduced in breast cancer cells treated with MCFAs. However, no significant changes in apoptosis and signaling-related proteins were observed in lauric acid-treated ER-positive cancer cells. Our findings suggested that MCFAs suppressed breast cancer cell proliferation by modulating the PI3K/Akt/mTOR signaling pathway. MCFAs may be a promising therapeutic drug for treating breast cancer., (© 2024 Wiley Periodicals LLC.)

Breast cancer has become the most commonly diagnosed cancer. Heterogeneous nuclear ribonucleoprotein C (HNRNPC), a reader of N6-methyladenosine (m6A), has been observed to be upregulated in various types of cancer. Nevertheless, the role of HNRNPC in breast cancer and whether it is regulated by m6A modification deserve further investigation. The expression of HNRNPC in breast cancer was examined by quantitative real-time polymerase chain reaction and western blot analysis. RNA immunoprecipitation was performed to validate the binding relationships between HNRNPC and WD repeat domain 77 (WDR77). The effects of HNRNPC and m6A regulators on WDR77 were investigated by actinomycin D assay. The experiments in vivo were conducted in xenograft models. In this research, we found that HNRNPC was highly expressed in breast cancer, and played a crucial role in cell growth, especially in the luminal subtype. HNRNPC could combine and stabilize WDR77 mRNA. WDR77 successively drove the G1/S phase transition in the cell cycle and promoted cell proliferation. Notably, this regulation axis was closely tied to the m6A modification status of WDR77 mRNA. Overall, a critical regulatory mechanism was identified, as well as promising targets for potential treatment strategies for luminal breast cancer., (© 2024 Wiley Periodicals LLC.)

The histone variant, macroH2A (mH2A) influences gene expression through epigenetic regulation. Tumor suppressive function of mH2A isoforms has been reported in various cancer types, but few studies have investigated the functional role of mH2A2 in breast cancer pathophysiology. This study aimed to determine the significance of mH2A2 in breast cancer development and progression by exploring its downstream regulatory mechanisms. Knockdown of mH2A2 facilitated the migration and invasion of breast cancer cells, whereas its overexpression exhibited the opposite effect. In vivo experiments revealed that augmenting mH2A2 expression reduced tumor growth and lung metastasis. Microarray analysis showed that TM4SF1 emerged as a likely target linked to mH2A2 owing to its significant suppression in breast cancer cell lines where mH2A2 was overexpressed among the genes that exhibited over twofold upregulation upon mH2A2 knockdown. Suppressing TM4SF1 reduced the migration, invasion, tumor growth, and metastasis of breast cancer cells in vitro and in vivo. TM4SF1 depletion reversed the increased aggressiveness triggered by mH2A2 knockdown, suggesting a close interplay between mH2A2 and TM4SF1. Our findings also highlight the role of the mH2A2/TM4SF1 axis in activating the AKT/NF-κB pathway. Consequently, activated NF-κB signaling leads to increased expression and secretion of MMP13, a potent promoter of metastasis. In summary, we propose that the orchestrated regulation of the mH2A2/TM4SF1 axis in conjunction with the AKT/NF-κB pathway and the subsequent elevation in MMP13 expression constitute pivotal factors governing the malignancy of breast cancer., (© 2024 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

Golgi-derived microtubule (MT) arrays are essential to directionally persistent cell migration and vesicle transport. In this study, we have examined MT nucleation sites in two breast cancer cell lines, MDA-MB-231 and MCF-7, with the hypothesis that only the migratory invasive MDA-MB-231 cells exhibit MTs originating from the Golgi. MTs were disassembled and allowed to slightly regrow so individual nucleation sites could then be observed via fluorescently tagged antibodies (α-tubulin, cis-Golgi marker GM130, and EB1-a MT plus-end binding protein) and confocal microscopy. To determine if MT nucleation at the Golgi is more apparent during active migration compared to when cells are stationary, cells were treated with the chemoattractant epidermal growth factor (EGF) and examined for colocalizations between the Golgi, α-tubulin, and γ-tubulin. Images were analyzed qualitatively for color overlap, and quantitatively using Manders Colocalization Coefficients. Differences between groups were tested for significance using one-way analysis of variances and Tukey's post hoc test. Significantly higher colocalization values (coloc) in the highly invasive MDA-MB-231 cells (α-tubulin coloc GM130 = 0.39, GM130 coloc α-tubulin = 0.82, GM130 coloc EB1 = 0.24, and EB1 coloc GM130 = 0.38) compared to the weakly invasive MCF-7 cells (0.15, 0.08, 0.02, and 0.16, respectively) were observed. EGF-treated cells exhibited higher colocalization values than control cells for three of the four protein combinations tested, but EGF-treated MDA-MB-231 cells exhibited significantly higher values (α-tubulin coloc GM130 = 0.20, GM130 coloc α-tubulin = 0.89, and γ-tubulin coloc GM130 = 0.47) than both control groups as well as the EGF-treated MCF-7 cells. Results support the hypothesis that MT nucleation at the Golgi occurs more frequently in the invasive MDA-MB-231 cell line compared to the weakly invasive MCF-7 cells. The presence or absence of Golgi-derived MTs may help to explain the difference in migratory potential commonly exhibited by these two cell lines., (© 2023 The Authors. Cytoskeleton published by Wiley Periodicals LLC.)

Epigenetic modifications play a significant role in cancer progression, making them potential targets for therapy. Histone deacetylase inhibitors have shown promise in inhibiting cancer cell growth, including in breast cancer (BC). In this research, we examined the potential of using suberoyl anilide hydroxamic acid (SAHA)-loaded β-lg nanofibrils as a drug delivery system for triple-negative BC cell lines. We assessed their impact on cell cycle progression, apoptosis, levels of reactive oxygen species, and mitochondrial membrane potential in cancer cells. The combination of SAHA and β-lg nanofibrils demonstrated enhanced efficacy in inhibiting cell growth, inducing cell cycle arrest, and promoting apoptosis (43.78%) compared to SAHA alone (40.09%). Moreover, it effectively targeted cancer cells without promoting drug resistance while using a low concentration of the nanofibrils. These findings underscore the promising potential of nanofibril-based drug delivery systems for BC treatment., (© 2024 Wiley Periodicals LLC.)

Estrogen receptor is an important target in breast cancer. Serotonin receptors (5-HT 2A and 5-HT 2C , in particular) were investigated for a potential role in development and progression of breast cancer. Ligands that interact with estrogenic receptors influence the emotional state of females. Thus, designing selective estrogen receptor modulator (SERM) analogs with potential serotonergic activity is a plausible approach. The dual ligands can augment cytotoxic effect of SERMs, help in both physical and emotional menopausal symptom relief, enhance cognitive function and support bone health. Herein, we report triarylethylene analogs as potential candidates for treatment of breast cancer. Compound 2e showed (ERα relative β- galactosidase activity = 0.70), 5-HT 2A (K i  = 0.97 µM), and 5-HT 2C (K i  = 3.86 µM). It was more potent on both MCF-7 (GI 50  = 0.27 µM) and on MDA-MB-231 (GI 50  = 1.86 µM) compared to tamoxifen (TAM). Compound 4e showed 40 times higher antiproliferative activity on MCF-7 and 15 times on MDA-MBA compared to TAM. Compound 4e had higher average potency than TAM on all nine tested cell line panels. Our in-silico model revealed the binding interactions of compounds 2 and 2e in the three receptors; further structural modifications are suggested to optimize binding to the ERα, 5-HT 2A , and 5-HT 2C ., (© 2023 Wiley Periodicals LLC.)

Cyclin dependent kinase 4 and 6 inhibitors such as abemaciclib are routinely used to treat metastatic estrogen receptor positive (ER+) breast cancer. However, adaptive mechanisms inhibit their effectiveness and allow for disease progression. Using ER+ breast cancer cell models, we show that acquired resistance to abemaciclib is accompanied by increase in metastatic potential. Mass spectrometry-based proteomics from abemaciclib sensitive and resistant cells showed that lysosomal proteins including CTSD (cathepsin D), cathepsin A and CD68 were significantly increased in resistant cells. Combination of abemaciclib and a lysosomal destabilizer, such as hydroxychloroquine (HCQ) or bafilomycin A1, resensitized resistant cells to abemaciclib. Also, combination of abemaciclib and HCQ decreased migration and invasive potential and increased lysosomal membrane permeability in resistant cells. Prosurvival B cell lymphoma 2 (BCL2) protein levels were elevated in resistant cells, and a triple treatment with abemaciclib, HCQ, and BCL2 inhibitor, venetoclax, significantly inhibited cell growth compared to treatment with abemaciclib and HCQ. Furthermore, resistant cells showed increased levels of Transcription Factor EB (TFEB), a master regulator of lysosomal-autophagy genes, and siRNA mediated knockdown of TFEB decreased invasion in resistant cells. TFEB was found to be mutated in a subset of invasive human breast cancer samples, and overall survival analysis in ER+, lymph node-positive breast cancer showed that increased TFEB expression correlated with decreased survival. Collectively, we show that acquired resistance to abemaciclib leads to increased metastatic potential and increased levels of protumorigenic lysosomal proteins. Therefore, the lysosomal pathway could be a therapeutic target in advanced ER+ breast cancer., (© 2023 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

Epithelial-mesenchymal transition (EMT) is a vital process in tumorigenesis and metastasis of breast cancer. In our quest to explore effective anticancer alternatives, ursolic acid (UA) was purified from Capparis zeylanica and investigated for its anticancer activity against MDA-MB-231 and MCF-7 breast cancer cells. The apparent anticancer activity of UA on MDA-MB-231 and MCF-7 cells was evident from IC50 values of 14.98 and 15.99 μg/mL, respectively, in MTT assay and also through enhanced generation of ROS. When MDA-MB-231 and MCF-7 cells were treated with 20 μg/mL UA, an absolute decrease in cell viability of 47.6% and 48.6%, enhancement of 1.35% and 1.10% in early apoptosis, and 21.90% and 21.35% in late apoptosis, respectively and G 0 /G 1 phase, S phase, G 2 /M phase cell cycle arrest was noticed. The gene expression studies revealed that UA could significantly (p < 0.001) downregulate the expression of EMT markers such as snail, slug, and fibronectin at molecular level. Further, the obtained in vitro results of snail, slug, and fibronectin were subjected to quantum-polarized-ligand (QM/MM) docking, which predicted that the in silico binding affinities of these three markers are in good correlation with strong hydrogen and van der Waal interactions to UA with -53.865, -48.971 and -40.617 MMGBSA (ΔG bind ) scores, respectively. The long-range molecular dynamics (50 ns) simulations have showed more consistency by UA. These findings conclude that UA inhibits breast cancer cells growth and proliferation through regulating the expression of key EMT marker genes, and thus UA is suggested as a potential anticancer agent., (© 2023 Wiley Periodicals LLC.)

Identification of biomarkers by integrating multiple omics together is important because complex diseases occur due to an intricate interplay of various genetic materials. Traditional single-omics association tests neither explore this crucial interomics dependence nor identify moderately weak signals due to the multiple-testing burden. Conversely, multiomics data integration imparts complementary information but suffers from an increased multiple-testing burden, data diversity inherent with different omics features, high-dimensionality, and so forth. Most of the available methods address subtype classification using dimension-reduction techniques to circumvent the sample size issue but interacting multiomics biomarker identification methods are unavailable. We propose a two-step model that first investigates phenotype-omics association using logistic regression. Then, selects disease-associated omics using sparse principal components which explores the interrelationship of multiple variables from two omics in a multivariate multiple regression framework. On the basis of this model, we developed a multiomics biomarker identification algorithm, interacting omics search (ioSearch), that jointly tests the effect of multiple omics with disease and between-omics associations by using pathway information that subsequently reduces the multiple-testing burden. Further, inference in terms of p values potentially makes it an easily interpretable biomarker identification tool. Extensive simulation demonstrates ioSearch as statistically powerful with a controlled Type-I error rate. Its application to publicly available breast cancer data sets identified relevant omics features in important pathways., (© 2023 Wiley Periodicals LLC.)

Background: Multiparametric MRI radiomics could distinguish human epidermal growth factor receptor 2 (HER2)-positive from HER2-negative breast cancers. However, its value for further distinguishing HER2-low from HER2-negative breast cancers has not been investigated., Purpose: To investigate whether multiparametric MRI-based radiomics can distinguish HER2-positive from HER2-negative breast cancers (task 1) and HER2-low from HER2-negative breast cancers (task 2)., Study Type: Retrospective., Population: Task 1: 310 operable breast cancer patients from center 1 (97 HER2-positive and 213 HER2-negative); task 2: 213 HER2-negative patients (108 HER2-low and 105 HER2-zero); 59 patients from center 2 (16 HER2-positive, 27 HER2-low and 16 HER2-zero) for external validation., Field Strength/sequence: A 3.0 T/T1-weighted contrast-enhanced imaging (T1CE), diffusion-weighted imaging (DWI)-derived apparent diffusion coefficient (ADC)., Assessment: Patients in center 1 were assigned to a training and internal validation cohort at a 2:1 ratio. Intratumoral and peritumoral features were extracted from T1CE and ADC. After dimensionality reduction, the radiomics signatures (RS) of two tasks were developed using features from T1CE (RS-T1CE), ADC (RS-ADC) alone and T1CE + ADC combination (RS-Com)., Statistical Tests: Mann-Whitney U tests, the least absolute shrinkage and selection operator, receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA)., Results: For task 1, RS-ADC yielded higher area under the ROC curve (AUC) in the training, internal, and external validation of 0.767/0.725/0.746 than RS-T1CE (AUC = 0.733/0.674/0.641). For task 2, RS-T1CE yielded higher AUC of 0.765/0.755/0.678 than RS-ADC (AUC = 0.706/0.608/0.630). For both of task 1 and task 2, RS-Com achieved the best performance with AUC of 0.793/0.778/0.760 and 0.820/0.776/0.711, respectively, and obtained higher clinical benefit in DCA compared with RS-T1CE and RS-ADC. The calibration curves of all RS demonstrated a good fitness., Data Conclusion: Multiparametric MRI radiomics could noninvasively and robustly distinguish HER2-positive from HER2-negative breast cancers and further distinguish HER2-low from HER2-negative breast cancers., Evidence Level: 3., Technical Efficacy: Stage 2., (© 2023 International Society for Magnetic Resonance in Medicine.)

Breast cancer represents a life-threatening problem globally. The major challenge in the clinical setting is the management of cancer resistance and metastasis. Hybrid therapy can affect several cellular targets involved in carcinogenesis with a lessening of adverse effects. Therefore, the current study aims to assemble, and optimize a hybrid of gefitinib (GFT) and simvastatin (SIM)-loaded nanostructured lipid carrier (GFT/SIM-NLC) to combat metastatic and drug-resistant breast cancer. GFT/SIM-NLC cargos were prepared using design of experiments to investigate the impact of poloxamer-188 and fatty acids concentrations on the physicochemical and pharmaceutical behavior properties of NLC. Additionally, the biosafety of the prepared GFT/SIM-NLC was studied using a fresh blood sample. Afterward, the optimized formulation was subjected to an MTT assay to study the cytotoxic activity of GFT/SIM-NLC compared to free GFT/SIM using an MCF-7 cell line as a surrogate model for breast cancer. The present results revealed that the particle size of the prepared NLC ranged from (209 to 410 nm) with a negative zeta potential value ranging from (-17.2 to -23.9 mV). Moreover, the optimized GFT/SIM-NLC formulation showed favorable physicochemical properties and promising lymphatic delivery cargos. A biosafety study indicates that the prepared NLC has a gentle effect on erythrocyte hemolysis. Cytotoxicity studies revealed that GFT/SIM-NLC enhanced the killing of the MCF-7 cell line compared to free GFT/SIM. This study concluded that the hybrid therapy of GFT/SIM-NLC is a potential approach to combat metastatic and drug-resistant breast cancer., (© 2023 Wiley Periodicals LLC.)

Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase receptor that plays a carcinogenic role in breast cancer (BC) through gene amplification, mutation, or overexpression. Traditional methods of HER2 detection were divided into positive (immunohistochemistry (IHC) 3+/fluorescence in situ hybridization (FISH) amplification) and negative (IHC 2+/FISH-, IHC 1+, IHC 0) according to the dichotomy method. Anti-HER2-targeted therapies, such as trastuzumab and pertuzumab, have significantly improved the prognosis of HER2-positive patients. However, up to 75% to 85% of patients remain HER2-negative. In recent years, with the rapid development of molecular biology, gene detection technology, targeted therapy, and immunotherapy, researchers have actively explored the clinicopathological characteristics, molecular biological characteristics, treatment methods, and HER2 detection methods of HER2-low/zero breast cancer. With the clinical efficacy of new anti-HER2 targeted drugs, accurate classification of breast cancer is very important for the treatment choice. Therefore, the following review summarizes the necessity of developing HER2 detection methods, and the clinicopathological and drug treatment characteristics of patients with HER2-low/zero, to light the dawn of the treatment of breast cancer patients with HER2-low/zero expression., (© 2023 UICC.)

Cell division cycle 123 (CDC123) has been implicated in a variety of human diseases. However, it remains unclear whether CDC123 plays a role in tumorigenesis and how its abundance is regulated. In this study, we found that CDC123 was highly expressed in breast cancer cells, and its high expression was positively correlated with a poor prognosis. Knowndown of CDC123 impaired the proliferation of breast cancer cells. Mechanistically, we identified a deubiquitinase, ubiquitin-specific peptidase 9, X-linked (USP9X), that could physically interact with and deubiquitinate K48-linked ubiquitinated CDC123 at the K308 site. Therefore, the expression of CDC123 was positively correlated with USP9X in breast cancer cells. In addition, we found that deletion of either USP9X or CDC123 led to altered expression of cell cycle-related genes and resulted in the accumulation of cells population in the G0/G1 phase, thereby suppressing cell proliferation. Treatment with the deubiquitinase inhibitor of USP9X, WP1130 (Degrasyn, a small molecule compound that USP9X deubiquitinase inhibitor), also led to the accumulation of breast cancer cells in the G0/G1 phase, but this effect could be rescued by overexpression of CDC123. Furthermore, our study revealed that the USP9X/CDC123 axis promotes the occurrence and development of breast cancer through regulating the cell cycle, and suggests that it may be a potential target for breast cancer intervention. In conclusion, our study demonstrates that USP9X is a key regulator of CDC123, providing a novel pathway for the maintenance of CDC123 abundance in cells, and supports USP9X/CDC123 as a potential target for breast cancer intervention through regulating the cell cycle., (© 2023 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

Forkhead Box Q1 (FoxQ1) transcription factor is overexpressed in luminal-type and basal-type human breast cancers when compared to normal mammary tissue. This transcription factor is best known for its role in promotion of breast cancer stem-like cells and epithelial to mesenchymal transition. The present study documents a novel function of FoxQ1 in breast cancer cells. Overexpression of FoxQ1 in basal-like SUM159 cells and luminal-type MCF-7 cells resulted in increased conversion of microtubule-associated protein light chain 3 beta-I (LC3B-I) to LC3B-II, which is a hallmark of autophagy. Autophagy induction by FoxQ1 overexpression was confirmed by visualization of LC3B puncta as well as by transmission electron microscopy. Expression profiling for genes implicated in autophagy regulation revealed upregulation of many genes, including ATG4B, ATG16L1, CTSS, CXCR4 and so forth but downregulation of BCL2L1, DRAM1, TNF, ULK2 and so forth by FoxQ1 overexpression in SUM159 cells. Western blot analysis confirmed upregulation of ATG4B and CXCR4 proteins by FoxQ1 overexpression in both SUM159 and MCF-7 cells. Chromatin immunoprecipitation assay revealed recruitment of FoxQ1 at the promoter of ATG4B. Pharmacological inhibition of ATG4B using S130 significantly increased apoptosis induction by DOX in empty vector transfected as well as FoxQ1 overexpressing SUM159 and MCF-7 cells but this effect was statistically significantly lowered by FoxQ1 overexpression indicating the protective role of FoxQ1 on apoptosis. Treatment of SUM159 cells with S130 and DOX enhanced LC3B-II level in both empty vector transfected cells and FoxQ1 overexpressing SUM159 cells but not in FoxQ1 overexpressing MCF-7 cells. In conclusion, FoxQ1 is a novel regulator of autophagy., (© 2023 Wiley Periodicals LLC.)

MicroRNAs regulate breast stemness and self-renewal properties in breast cancer cells at the molecular level. Recently we reported the clinical relevance and in vitro expression profile of novel miR-6844 in breast cancer and -derived stem-like cells (mammosphere). In the present study, we first time explore the functional role of loss of miR-6844 in breast cancer cells derived mammosphere. Down expression of miR-6844 significantly decreased cell proliferation in MCF-7 and T47D cells derived mammosphere in a time-dependent manner. MiR-6844 down expression reduced the sphere formation in terms of size and number in test cells. Loss of miR-6844 significantly altered stemness and self-renewal markers (Bmi-1, Nanog, c-Myc, Sox2, and CD44) in mammosphere compared to negative control spheres. Moreover, loss of miR-6844 inhibits the JAK2-STAT3 signaling pathway by decreasing p-JAK2 and p-STAT3 levels in breast cancer cells derived mammosphere. Loss of miR-6844 expression significantly decreased CCND1 and CDK4 mRNA/protein levels and arrested breast cancer stem-like cells in G2/M phase. Reduced expression of miR-6844 increased Bax/Bcl-2 ratio, late apoptotic cell population, and Caspase 9 and 3/7 activity in the mammosphere. Low expression of miR-6844 decreased migratory and invasive cells by altering the expression of Snail, E-cad, and Vimentin at mRNA/protein levels. In conclusion, loss of miR-6844 decreases stemness/self-renewal and other cancer hallmark in breast cancer stem-like cells through CD44-JAK2-STAT3 axis. Thus, downregulation of miR-6844 by therapeutic agents might be a novel strategy to target breast cancer stemness and self-renewal., (© 2023 Wiley Periodicals LLC.)

In tumor microenvironment (TME), macrophages trigger and maintain inflammatory responses that promoting tumor progression. Many cellular proteins are secreted from tumors and modulate their own TME by modulating macrophage phenotypes. Recently, we reported that interferon-γ-inducible protein 16 (IFI16), which was identified as an innate immune DNA sensor recognizing foreign DNA, triggered type Ⅰ interferon responses in breast cancer (BC). However, whether IFI16 was released from BC and affects TME has not been studied. Here, we report that IFI16 and its mouse homolog Ifi202 were released from BC cells, but not from normal epithelial cells. Ifi202 induced secretion of proinflammatory cytokines such as Interleukin (IL)-1β, IL-6, and Tumor necrosis factor-α from macrophages via binding toll-like receptor 2 and activating downstream signaling pathway. Growth of allografted mouse BC 4T1 lacking Ifi202 was suppressed and accompanied with increased infiltration and cytotoxic activity of CD8+ T lymphocytes. Further, IFI16 was detected in sera of patients with BC. High expression level of IFI16 was associated with poor prognosis in patients with BC. Taken together, our findings suggest a novel role of IFI16/Ifi202 in TME, that elicits tumor promoting inflammation and thereby shaping immunosuppressive TME in BC., (© 2023 Wiley Periodicals LLC.)

The epidemic spread of obesity is nowadays recognized as a global health and economic burden, arising great interest in the scientific community. The rate of adult obesity steadily increases concomitantly with the cancer incidence. As has been comprehensively reported, obesity is included among the multiple cancer risk factors and can progressively cause and/or exacerbate certain cancer types, as colorectal and breast cancers. The term adiponcosis was forged precisely to emphasize the interconnection between obesity and cancer onset and progression. The underlying mechanisms of adiponcosis have not been fully elucidated yet, may vary on cancer type, and depend on body fat distribution. It has been proposed that insulin resistance and related chronic hyperinsulinemia, increased insulin-like growth factors production, chronic inflammation or increased bioavailability of steroid hormones could be responsible of cancer hallmarks. Additionally, it has been suggested that adipose tissue-derived hormones, cytokines and adipokines, such as leptin, adiponectin and inflammatory markers, may reflect mechanisms linked to tumorigenesis. This review summarizes the current evidence on pathways, hormones, cytokines and low-chronic inflammation subtending adiponconsis, focusing on breast and colorectal cancers. In addition, we analyzed the lifestyle interventions that could attenuate the driving forces of obesity-related cancer incidence and progression. Moreover, current targets and drugs, their pros and cons, as well as new mechanisms and targets with promising therapeutic potential in cancer are discussed. Depicting this complex interconnection will provide insights for establishing new therapeutic approaches to halt the obesity impacts and thwart cancer onset and progression., (© 2022 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

The unobtrusive cold environmental temperature can be linked to the development of cancer. This study, for the first time, envisaged cold stress-mediated induction of a zinc finger protein 726 (ZNF726) in breast cancer. However, the role of ZNF726 in tumorigenesis has not been defined. This study investigated the putative role of ZNF726 in breast cancer tumorigenic potency. Gene expression analysis using multifactorial cancer databases predicted overexpression of ZNF726 in various cancers, including breast cancer. Experimental observations found that malignant breast tissues and highly aggressive MDA-MB-231 cells showed an elevated ZNF726 expression as compared to benign and luminal A type (MCF-7), respectively. Furthermore, ZNF726 silencing decreased breast cancer cell proliferation, epithelial-mesenchymal transition, and invasion accompanied by the inhibition of colony-forming ability. Concordantly, ZNF726 overexpression significantly demonstrated opposite outcomes than ZNF726 knockdown. Taken together, our findings propose cold-inducible ZNF726 as a functional oncogene demonstrating its prominent role in facilitating breast tumorigenesis. An inverse correlation between environmental temperature and total serum cholesterol was observed in the previous study. Furthermore, experimental outcomes illustrate that cold stress elevated cholesterol content hinting at the involvement of the cholesterol regulatory pathway in cold-induced ZNF726 gene regulation. This observation was bolstered by a positive correlation between the expression of cholesterol-regulatory genes and ZNF726. Exogenous cholesterol treatment elevated ZNF726 transcript levels while knockdown of ZNF726 decreased the cholesterol content via downregulating various cholesterol regulatory gene expressions (e.g., SREBF1/2, HMGCoR, LDLR). Moreover, an underlying mechanism supporting cold-driven tumorigenesis is proposed through interdependent regulation of cholesterol regulatory pathway and cold-inducible ZNF726 expression., (© 2023 Wiley Periodicals LLC.)

Metastasis in breast cancer usually lead to the majority of deaths on clinical patients. Accordingly, diagnosis of metastasis at the early stage in breast cancer is important to improve the prognosis. We observed that Dicer protein levels are significant decrease in highly invasive breast cancer cells and usually correlated with poor clinical outcomes. Following, we aim to clarify the molecular regulatory mechanism of this phenomenon in breast cancer to provide a new therapeutic target. In this study, we obtained that Dicer expression correlated with metastasis and invasion without affect cell stability in breast cancer cells. Importantly, we identified the regulatory mechanism of Dicer protein degradation, the chaperone-mediated autophagy (CMA)-mediated degradation that is major mechanism to decrease Dicer protein expression and lead to cancer metastasis. We discovered that heat shock cognate 71-kDa protein (Hsc70) which as a CMA-related factor interacts with the CMA-targeting motif I333A/K334A on Dicer to promote degradation through CMA. Taken together, our findings hint that Dicer highly correlated with cancer metastasis, we reveal the tumor-promoting effect of CMA-mediated Dicer degradation in breast cancer., (© 2023 Wiley Periodicals LLC.)

MiR-1283 has been identified as a tumor suppressor in some malignancies. Whereas, the role of miR-1283 in HER2-positive (HER2+) breast cancer, particularly its role in regulating cell proliferation, one of the most significant features of tumor progression, is unclear. The related microRNA screened by the breast cancer sample GSE131599 dataset were detected in HER2+ breast cancer tissues and cell lines. Then, the obtained miR-1283 was overexpressed in SKBR3 and BT-474 cells followed by relevant functional assays concerning cell proliferation and apoptosis. The xenograft mouse model was induced and the effect of miR-1283 on tumor growth and cell proliferation was examined. The target of miR-1283 and the transcription factor regulating miR-1283 were predicted and identified. Finally, the influence of transcription factor KLF14 on cell proliferation and apoptosis was investigated. An integrated analysis confirmed that miR-1283 expression was significantly decreased in HER2+ breast cancer tissues. Also, by q-RT-PCR detection, miR-1283 expression was markedly reduced in HER2+ breast cancer tissues and cell lines. The miR-1283 overexpression prevented the proliferation and enhanced apoptosis of HER2+ breast cancer cells, as well as inhibited tumor growth. Mechanistically, miR-1283 inhibited TFAP2C expression by targeting the 3'-untranslated regions of TFAP2C messenger RNA, and the KLF14 enhanced miR-1283 level via binding to its promoter. The result subsequently confirmed the KLF14/miR-1283 signaling suppressed cell proliferation in HER2+ breast cancer. Our results suggested that the KLF14/miR-1283/TFAP2C axis inhibited HER2+ breast cancer progression, which might provide novel insight into mechanical exploration for this disease., (© 2023 Wiley Periodicals LLC.)

Background: Amide proton transfer (APT) imaging has been increasingly applied in tumor characterization. However, its value in evaluating breast cancer remains undetermined., Purpose: To assess the diagnostic performance of APT imaging in breast cancer and its association with prognostic histopathologic characteristics., Study Type: Prospective., Subjects: Eighty-four patients with breast lesions., Field Strength/sequence: A 3.0 T/single-shot fast spin echo APT imaging., Assessment: APTw signal in breast lesion was quantified. Lesion malignancy, T stage, grades, Ki-67 index, molecular biomarkers (estrogen receptor [ER] expression, progesterone receptor [PR] expression, human epidermal growth factor receptor [HER-2] expression), molecular subtypes (luminal A, luminal B, triple negative, and HER-2 enriched) were determined., Statistical Tests: Student t-test, one-way analysis of variance, receiver operating characteristic analysis, and Pearson's correlation with P < 0.05 as statistical significance., Results: APTw signal was significantly higher in malignant lesions (1.55% ± 1.24%) than in benign lesions (0.54% ± 1.13%), and in grade III lesions than in grade II lesions (1.65% ± 0.84% vs. 0.96% ± 0.96%), and in T2- (1.57% ± 0.64%) and T3-stage lesions (1.54% ± 0.63%) than in T1-stage lesions (0.81% ± 0.64%) for invasive breast carcinoma of no special type. APTw signal significantly correlated with Ki-67 index (r = 0.364) but showed no significant difference in groups of ER (P = 0.069), PR (P = 0.069), HER-2 (P = 0.961), and among molecular subtypes (P = 0.073)., Data Conclusion: APT imaging shows potential in differentiating breast lesion malignancy and associates with prognosis-related tumor grade, T stage, and proliferative activity., Evidence Level: 2 TECHNICAL EFFICACY: Stage 2., (© 2022 International Society for Magnetic Resonance in Medicine.)

Breast cancer is the most common cancer in women worldwide. Although tamoxifen (TAM), a selective estrogen receptor (ER) modulator, is widely used to treat ER-positive breast cancers, resistance to TAM remains a major clinical problem. NADPH-dependent cytochrome P450 reductase (POR) is known to participate in drug metabolism and steroid metabolism. Recent studies showed that high POR expression was correlated with poor outcomes in triple-negative breast cancer (TNBC), and POR might be a prognostic biomarker in TNBC. However, the role of POR in TAM resistance is still elusive. In this study, we found that high POR expression was associated with poor prognosis of ER-positive and TAM-treated breast cancer patients. In addition, COX analysis showed that POR expression was an independent prognostic biomarker for ER-positive as well as TAM-treated breast cancer patients. Furthermore, our results suggested that POR overexpression promoted TAM resistance by activating the STAT1/c-Myc pathway in ER-positive breast cancer cells. Immunohistochemical analysis showed that high POR/STAT1 expression was correlated with poor prognosis in TAM-treated breast cancer patients. Notably, combined treatment with TAM and a specific STAT1 inhibitor Fludarabine was more effective for inhibiting TAM-resistant breast cancer cells. Altogether, our findings suggested that POR overexpression induced TAM resistance through STAT1/c-Myc pathway and might serve as an independent prognostic biomarker in TAM-treated breast cancer patients. Combining TAM and STAT1 inhibitors might be an effective strategy for treating POR-induced TAM-resistant breast cancer., (© 2022 Wiley Periodicals LLC.)

Background: Disagreement in assessments of Ki67 expression based on core-needle biopsy and matched surgical samples complicates decisions in the treatment of breast cancer., Purpose: To examine whether preoperative breast MRI could be useful in predicting Ki67 discordance between core-needle biopsy and surgical samples., Study Type: Retrospective., Population: Three hundred and sixty-five breast cancer patients with MRI scans and having both core-needle biopsy and surgical samples from 2017 to 2019., Field Strength/sequence: 3.0 T, T2-weighted iterative decomposition of water and fat with echo asymmetry and least squares estimation sequence, diffusion-weighted sequence using b-values 0/1000, dynamic contrast enhanced image by volume imaged breast assessme NT., Assessment: We collected clinicopathologic variables and preoperative MRI features (tumor size, lesion type, shape of mass, spiculated margin, internal enhancement, peri-tumoral edema, intra-tumoral necrosis, multifocal/multicentric, apparent diffusion coefficient [ADC] minimum, ADC mean, ADC maximum, ADC difference)., Statistical Tests: K-means clustering, multivariable logistic regression, receiver operating characteristic curve., Results: Sixty-one patients showed Ki67 discordance and 304 patients show Ki67 concordance according to our definition using K-means clustering. Multivariable regression analysis showed that the following parameters were independently associated with Ki67 discordance: peri-tumoral edema, odds ratio (OR) 2.662, 95% confidence interval (CI) 1.432-4.948; ADCmin ≤ 0.829 × 10 -3  mm 2 /sec, OR 2.180, 95% CI 1.075-4.418; and ADCdiff > 0.317 × 10 -3  mm 2 /sec, OR 3.365, 95% CI 1.698-6.669. This multivariable model resulted in an AUC of 0.758 (95% CI 0.711-0.802) with sensitivity and specificity being 0.803 and 0.621, respectively., Conclusion: Presence of peri-tumoral edema, smaller ADCmin and greater ADCdiff in preoperative breast MRI may indicate high risk of Ki67 discordance between core-needle biopsy and surgical samples. For patients with these MRI-based risk factors, clinicians should not rely on Ki67 assessment only from core-needle biopsy., (© 2022 International Society for Magnetic Resonance in Medicine.)

Ineffective cancer treatment is implicated in metastasis, recurrence, resistance to chemotherapy and radiotherapy, and evasion of immune surveillance. All these failures occur due to the persistence of cancer stem cells (CSCs) even after rigorous therapy, thereby rendering them as essential targets for cancer management. Contrary to the quiescent nature of CSCs, a gene profiler array disclosed that phosphatidylinositol-3-kinase (PI3K), which is known to be crucial for cell proliferation, differentiation, and survival, was significantly upregulated in CSCs. Since PI3K is modulated by cyclic adenosine 3',5' monophosphate (cAMP), analyses of cAMP regulation revealed that breast CSCs expressed increased levels of phosphodiesterase 4 (PDE4) in contrast to normal stem cells. In accordance, the effects of rolipram, a PDE4 inhibitor, were evaluated on PI3K regulators and signaling. The efficacy of rolipram was compared with paclitaxel, an anticancer drug that is ineffective in obliterating breast CSCs. Analyses of downstream signaling components revealed a switch between cell survival and death, in response to rolipram, specifically of the CSCs. Rolipram-mediated downregulation of PDE4A levels in breast CSCs led to an increase in cAMP levels and protein kinase A (PKA) expression. Subsequently, PKA-mediated upregulation of phosphatase and tensin homolog antagonized the PI3K/AKT/mTOR pathway and led to cell cycle arrest. Interestingly, direct yet noncanonical activation of mTOR by PKA, circumventing the influence of PI3K and AKT, temporally shifted the fate of CSCs toward apoptosis. Rolipram in combination with paclitaxel indicated synergistic consequences, which effectively obliterated CSCs within a tumor, thereby suggesting combinatorial therapy as a sustainable and effective strategy to abrogate breast CSCs for better patient prognosis., (© 2022 Wiley Periodicals LLC.)

Cell loss during detection and isolation of circulating tumor cells (CTCs) is a challenge especially when label-free pre-enrichment technologies are used without the aid of magnetic particles. Although microfluidic systems can remove the majority of "contaminating" white blood cells (WBCs), their remaining numbers are still impeding single CTC isolation, thus making additional separation steps needed. This study aimed to develop a workflow from blood-to-single CTC for complex cell suspensions by testing two microwell formats. In the first step, different cell lines were used to compare the performances of Sievewell™ 370 K (TOK, Japan) and CellCelector™ Nanowell U25 (ALS Automated Lab Solutions, Germany) slides for cell labelling and single-cell micromanipulation. Confounding levels of auto-fluorescence inherent to different plastic materials used to cast the microwells, staining recovery rates, and cell isolation rates were determined. In the second step, three different blood preservation tubes were tested for RNA analysis. Lastly, the established workflow was applied to isolate CTCs from peripheral blood samples obtained from metastasized breast cancer (mBC) patients for single-cell DNA and RNA analysis. The detection of CTCs in Sievewell slides profit from better signal-to-noise ratios in the fluorescence channels mainly used for CTC detection. In addition, due to its design, Sievewell supports direct in situ CTC labelling, which minimizes cell loss and leads to single-cell recovery rates after staining of approx. 94%. Detection of PIK3CA mutations in single CTCs verified the applicability of the workflow for the analysis of genomic DNA of CTCs. Furthermore, combined with blood preservation up to 48 h at room temperature in LBguard tubes, panel RT-PCR transcript analysis was successful for single cell line cells and CTCs, respectively. The combined use of Sievewell microwell slides and CellCelector™ automated micromanipulation system improves single CTC detection, labelling and isolation from complex cell suspensions. This approach is especially valuable when samples of high cellular content are processed., (© 2022 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.)

In patients with human epidermal growth factor receptor 2 positive (HER2+) breast cancer, leptomeningeal metastases (LM) are a rare but often a fatal clinical scenario. In this multicentric study, clinical and pathologic characteristics of patients with HER2+ breast cancer developing LM were described, as well as survival outcomes. Data were gathered retrospectively from medical records of 82 patients with advanced HER2+ breast cancer and LM treated between August 2005 and July 2020. Following LM diagnosis, 79 (96.3%) patients received at least one line of anti-HER2 therapy, 25 (30.5%) patients received intrathecal therapy and 58 (70.7%) patients received radiotherapy. Overall survival (OS) was 8.3 months (95% confidence interval [CI] 5.7-11), 1-year OS was 42%, and 2-year OS was 21%. At univariate analysis, patients who were treated after 2010, had better Karnofsky performance status, were free of neurological symptoms, had better prognostic, received chemotherapy (OS difference 9.4 months, P = .024), or monoclonal antibodies (trastuzumab ± pertuzumab; OS difference 6.1 months; P = .013) after LM diagnosis, had a statistically significantly longer OS. Presence of neurological symptoms (hazard ratio 3.32, 95% CI 1.26-8.73; P = .015) and not having received radiotherapy (hazard ratio 2.02, 95% CI 1.09-3.72; P = .024) were all associated with poorer OS at multivariate analysis. To summarize, not having neurological symptoms and receiving RT at LM diagnosis were associated with prolonged OS in our cohort. Survival seemed to be prolonged with multimodality treatment, which included targeted therapy, chemotherapy, and RT to the LM sites., (© 2022 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

A reduction in extracellular pH (pHe) is a characteristic of most malignant tumors. The aryl hydrocarbon receptor (AhR) is a transcription factor localized in a cytosolic complex with c-Src, which allows it to trigger nongenomic effects through c-Src. Considering that the slightly acidic tumor microenvironment promotes breast cancer progression in a similar way to the AhR/c-Src axis, our aim was to evaluate whether this pathway could be activated by low pHe. We examined the effect of pHe 6.5 on AhR/c-Src axis using two breast cancer cell lines (MDA-MB-231 and LM3) and mammary epithelial cells (NMuMG) and found that acidosis increased c-Src phosphorylation only in tumor cells. Moreover, the presence of AhR inhibitors prevented c-Src activation. Low pHe reduced intracellular pH (pHi), while amiloride treatment, which is known to reduce pHi, induced c-Src phosphorylation through AhR. Analyses were conducted on cell migration and metalloproteases (MMP)-2 and -9 activities, with results showing an acidosis-induced increase in MDA-MB-231 and LM3 cell migration and MMP-9 activity, but no changes in NMuMG cells. Moreover, all these effects were blocked by AhR and c-Src inhibitors. In conclusion, acidosis stimulates the AhR/c-Src axis only in breast cancer cells, increasing cell migration and MMP-9 activity. Although the AhR activation mechanism still remains elusive, a reduction in pHi may be thought to be involved. These findings suggest a critical role for the AhR/c-Src axis in breast tumor progression stimulated by an acidic microenvironment., (© 2022 Wiley Periodicals LLC.)

Recent studies have provided evidence for tumor suppressive function of the embryonic stem cell-specific miR-302/367 cluster through induction of a reprogramming process. Aspirin has been found to induce reprogramming factors of mesenchymal-to-epithelial transition in breast cancer cells. Therefore, we aimed to investigate whether overexpression of miR-302/367 cluster and aspirin treatment cooperate in the induction of reprogramming and tumor suppression in breast cancer cells. MDA-MB-231 and SK-BR-3 human breast cancer cell lines were transfected with a miR-302/367 expressing vector and treated with aspirin. The cells were evaluated for indices of apoptosis, proliferation, migration, and invasion. In both cell lines, treatment of miR-302/367-transfected cells with aspirin upregulated expression of some main pluripotency factors such as OCT4, SOX2, NANOG, and KLF4, and downregulated expression of some invasion and angiogenesis markers at gene and protein levels. Aspirin increased the apoptotic rate in both cell lines transfected with miR-302/367. Both miR-302/367 and aspirin upregulated the expression of FOXD3 protein which is a known inducer of OCT4 and NANOG. Our results demonstrate that aspirin can enhance miR-302/367-induced reprogramming of breast cancer cells possibly through upregulation of FOXD3 expression. This can further augment the reversal of epithelial-mesenchymal transition and inhibits migration, invasion, and angiogenic signaling in breast cancer cells reprogrammed by miR-302/367. Therefore, aspirin may serve as a useful adjuvant for reprogramming of cancer cells., (© 2022 Wiley Periodicals LLC.)

Arylamine N-acetyltransferase 1 (NAT1) is frequently upregulated in breast cancer. Previous studies showed that inhibition or depletion of NAT1 in breast cancer cells diminishes anchorage-independent growth in culture, suggesting that NAT1 contributes to breast cancer growth and metastasis. To further investigate the contribution of NAT1 to growth and cell invasive/migratory behavior, we subjected parental and NAT1 knockout (KO) breast cancer cell lines (MDA-MB-231, MCF-7, and ZR-75-1) to multiple assays. The rate of cell growth in suspension was not consistently decreased in NAT1 KO cells across the cell lines tested. Similarly, cell migration and invasion assays failed to produce reproducible differences between the parental and NAT1 KO cells. To overcome the limitations of in vitro assays, we tested parental and NAT1 KO cells in vivo in a xenograft model by injecting cells into the flank of immunocompromised mice. NAT1 KO MDA-MB-231 cells produced primary tumors smaller than those formed by parental cells, which was contributed by an increased rate of apoptosis in KO cells. The frequency of lung metastasis, however, was not altered in NAT1 KO cells. When the primary tumors of the parental and NAT1 KO cells were allowed to grow to a pre-determined size or delivered directly via tail vein, the number and size of metastatic foci in the lung did not differ between the parental and NAT1 KO cells. In conclusion, NAT1 contributes to primary and secondary tumor growth in vivo in MDA-MB-231 breast cancer cells but does not appear to affect its metastatic potential., (© 2022 Wiley Periodicals LLC.)

The microtubule-affinity regulating kinases (MARKs) family plays a crucial role in regulating breast cancer development and progression. However, its precise function and the relevant molecular mechanism in breast cancer have not yet been elucidated. In this study, analysis of The Cancer Genome Atlas (TCGA) data revealed that MARK2 expression was markedly upregulated in breast cancer tissues, and high expression of MARK2 was correlated with poor survival. Functional assays showed that MARK2 deletion or inhibition suppressed aerobic glycolysis and cell growth as well as induced cell cycle arrest and apoptosis in breast cancer cells. Mechanistically, MARK2 stimulates mTOR-mediated hypoxia-inducible factor 1 alpha (HIF-1α) transcription activity and represses p53-transcription activity in breast cancer cells. TCGA data revealed that MARK2 expression was positively correlated with mTOR, Raptor, S6K1, glucose transporter 1, lactate dehydrogenase, HIF-1α, and 4E-BP1 expression, whereas negatively correlated with p53, p21, and Bax in breast cancer tissue. Conclusively, our study demonstrated that MARK2 promotes breast cancer aerobic glycolysis and cell proliferation, and inhibits apoptosis, in part, through regulating mTOR/HIF-1α and p53 signaling pathways. Overall, these findings point to the potential of targeting MARK2 for breast cancer treatment., (© 2022 Wiley Periodicals LLC.)

Hypoxia-inducible factor 2α (HIF2α) plays a pivotal role in breast tumor growth and metastasis. However, the regulatory mechanisms of HIF2α protein stability remain poorly understood. The precise role of the deubiquitinase (DUB) ubiquitin-specific peptidase 5 (USP5) in breast cancer and the underlying mechanism remains largely unknown. Here, we identified USP5 as a novel DUB for HIF2α. Physically, USP5 interacts with HIF2α and protects HIF2α from ubiquitin-proteasome degradation, thereby promoting the transcription of HIF2α target genes, such as SLC2A1, PLOD2, P4HA1, and VEGFA. USP5 ablation impairs breast cancer cells proliferation, colony formation, migration, and invasion. Moreover, USP5 is highly expressed in breast cancer, and the protein levels of USP5 are positively correlated with HIF2α protein levels in human breast cancer tissues. Importantly, high levels of USP5 leads to poor clinical outcome in patients with breast cancer. Collectively, USP5 stabilizes HIF2α through its DUB activity and provides a potential therapeutic target for breast cancer., (© 2022 Wiley Periodicals LLC.)

HER2 signaling upregulation is a hallmark of breast cancer which is the second cause of cancer-related death in women. Here, we were looking for the candidate microRNAs which is capable of regulating the HER2 receptor and the genes of its downstream. To this aim, preliminary bioinformatics analysis introduced hsa-miR-1254 (miR-1254) as a potential common regulator of HER2, HER3, PIK3R2, and AKT1 genes. Then, reverse-transcription quantitative polymerase chain reaction (RT-qPCR) analysis indicated a lower expression level of miR-1254 in breast cancer specimens, compared to their normal pairs. Furthermore, overexpression of miR-1254 resulted in HER2, HER3, PIK3R2, and AKT1 genes downregulation, detected by RT-qPCR and confirmed by western blot analysis and enzyme-linked immunosorbent assay test against AKT1, BAX, FADD, and HER2 protein levels in SKBR3 cells. Dual-luciferase assay also supported direct interaction of miR-1254 with MREs within 3' untranslated region sequences of HER2, HER3, PIK3R2, and AKT1 target genes. Overexpression of miR-1254 in SKBR3 cells was followed by increased BAX/BCL2 expression ratio, detected by RT-qPCR, and increased proportion of G1 cell population, detected by flow cytometry. Corroborated by cell cycle analysis, MTT, Annexin V-FITC, and Live-Dead cell staining assays, overexpression of miR-1254 in MDA-MB-231 cells showed opposing results following the overexpression of miR-1254. Taken together, results indicated that miR-1254 acts as cell-type-specific tumor suppressor that targets HER2, HER3, PIK3R2, and AKT1 transcripts. These results suggest miR-1254 as a potential therapeutic candidate for breast cancer subtypes., (© 2022 Wiley Periodicals LLC.)