Resistance to chemotherapy continues to be a critical issue in the clinical therapy of triple‐negative breast cancer (TNBC). Epithelial–mesenchymal transition (EMT) is thought to contribute to ...chemoresistance in several cancer types, including breast cancer. Identification of the key signaling pathway that regulates the EMT program and contributes to chemoresistance in TNBC will provide a novel strategy to overcome chemoresistance in this subtype of cancer. Herein, we demonstrate that Notch1 positively associates with melanoma cell adhesion molecule (MCAM), a unique EMT activator, in TNBC tissue samples both at mRNA and protein levels. High expression of Notch1 and MCAM both predicts a poor survival in basal‐like/TNBC patients, particularly in those treated with chemotherapy. The expression of Notch1 and MCAM in MDA‐MB‐231 cells gradually increases in a time‐dependent manner when exposing to low dose cisplatin. Moreover, the expressions of Notch1 and MCAM in cisplatin‐resistant MDA‐MB‐231 cells are significantly higher than wild‐type counterparts. Notch1 promotes EMT and chemoresistance, as well as invasion and proliferation of TNBC cells via direct activating MCAM promoter. Inhibition of Notch1 significantly downregulates MCAM expression, resulting in the reversion of EMT and chemoresistance to cisplatin in TNBC cells. Our study reveals the regulatory mechanism of the Notch1 pathway and MCAM in TNBC and suggesting that targeting the Notch1/MCAM axis, in conjunction with conventional chemotherapies, might be a potential avenue to enhance the therapeutic efficacy for patients with TNBC.
What's new?
Epithelial‐mesenchymal transition (EMT) likely contributes to chemoresistance in triple‐negative breast cancers (TNBC), but the underlying mechanisms remain unclear. Here, the expression of Notch1 positively associated with melanoma cell adhesion molecule (MCAM), a unique EMT activator, in TNBC tissue samples. High expression of Notch1 and MCAM predicted poor survival, particularly in patients treated with chemotherapy. Notch1 and MCAM levels were significantly higher in cisplatin‐resistant than wild‐type TNBC cells. The findings suggest that Notch1 regulates MCAM in EMT and contributes to cisplatin resistance in TNBC. Targeting the Notch1/MCAM axis might be a potential avenue to enhance therapeutic efficacy in patients with TNBC.
Resistance to chemotherapy remains a significant problem in the treatment of breast cancer, especially for triple-negative breast cancer (TNBC), in which standard systemic therapy is currently ...limited to chemotherapeutic agents. Our study aimed to better understand the molecular mechanisms that lead to failure of chemotherapy in TNBC. Herein, we observed elevated expression of Notch1 and major vault protein (MVP) in MDA-MB-231DDPR cells compared to their parental counterparts. We demonstrated that Notch1 could positively regulate the expression of MVP. Also, Notch1 intracellular domain (ICD) was capable of binding to CBF-1 on the promoter of MVP to drive its transcription, resulting in activation of AKT pathway and promoting the progress of epithelial to mesenchymal transition (EMT). Conversely, silencing of Notch1 and MVP suppressed AKT pathway, reduced EMT and enhanced the sensitivity of TNBC cells to cisplatin and doxorubicin. Survival analysis indicated that the MVP was closely related to shorter recurrence-free survival (RFS) in patients with TNBC. Collectively, this study provides evidence that Notch1 activates AKT pathway and promotes EMT partly through direct activation of MVP. Targeting Notch1/MVP pathway appears to have potential in overcoming chemoresistance in TNBC.
•Both Notch1 and MVP were highly up-regulated and the AKT pathway was also activated in the MDA-MB-231 DDPR cells.•Notch1 could promote the expression of MVP and activate the AKT pathway as well as EMT process.•Notch1 could transcriptionally regulate MVP expression by binding to the MVP promoter.•MVP is associated with poor survival outcome and might serve as a unique predictive marker of chemotherapy response.
The chemokine CXCL9 (C-X-C motif chemokine ligand 9) has been reported to be required for antitumour immune responses following immune checkpoint blockade. In this study, we sought to investigate the ...potential value of CXCL9 according to immune responses in patients with breast cancer (BC). A variety of open-source databases and online tools were used to explore the expression features and prognostic significance of CXCL9 in BC and its correlation with immune-related biomarkers followed by subsequent verification with immunohistochemistry experiments. The CXCL9 mRNA level was found to be significantly higher in BC than in normal tissue and was associated with better survival outcomes in patients with ER-negative tumours. Moreover, CXCL9 is significantly correlated with immune cell infiltration and immune-related biomarkers, including CTLA4, GZMB, LAG3, PDCD1 and HAVCR2. Finally, we performed immunohistochemistry with breast cancer tissue samples and observed that CXCL9 is highly expressed in the ER-negative subgroup and positively correlated with the immune-related factors LAG3, PD1, PDL1 and CTLA4 to varying degrees. These findings suggest that CXCL9 is an underlying biomarker for predicting the status of immune infiltration in ER-negative breast cancer.
Basal-like breast cancer (BLBC) is an aggressive subtype with a strong tendency to metastasize. Due to the lack of effective chemotherapy, BLBC has a poor prognosis compared with luminal subtype ...breast cancer. MicroRNA-221 and -222 (miR-221/222) are overexpressed in BLBC and associate with metastasis as well as poor prognosis; however, the mechanisms by which miR-221/222 function as oncomiRs remain unknown. Here, we report that miR-221/222 expression is inversely correlated with Notch3 expression in breast cancer cell lines. Notch3 is known to be overexpressed in luminal breast cancer cells and inhibits epithelial to mesenchymal transition (EMT). We demonstrate that miR-221/222 target Notch3 by binding to its 3' untranslated region and suppressing protein translation. Ectopic expression of miR-221/222 significantly promotes EMT, whereas overexpression of Notch3 intracellular domain attenuates the oncogenic function of miR-221/222, suggesting that miR-221/222 exerts its oncogenic role by negatively regulating Notch3. Taken together, our results elucidated that miR-221/222 promote EMT via targeting Notch3 in breast cancer cell lines suggesting that miR-221/222 can serve as a potential therapeutic target in BLBC.
•DLGAP1-AS2 knockdown inhibits radioresistance of rectal cancer stem cells.•DLGAP1-AS2 elevates CD151 expression via interactions with E2F1.•DLGAP1-AS2 facilitates radioresistance of rectal cancer by ...interacting with E2F1 to upregulate CD151 expression.•DLGAP1-AS2 promotes radioresistance of rectal cancer via modulating E2F1 to elevate CD151 expression through activating AKT/mTOR/cyclinD1 signaling.
Radiotherapy resistance is one of the major causes of rectal cancer treatment failure. LncRNA DLGAP1-AS2 participates in the progression of several cancers. We explored the role and potential mechanism of DLGAP1-AS2 in the radioresistance of rectal cancer stem cells.
HR8348-R cells, radioresistant cells from HR8348 after irradiation, were isolated into CD133 negative (CD133−) and positive (CD133+) cells. Cell proliferation, apoptosis, migration and tumorsphere formation were determined by CCK-8, flow cytometry, wound healing assay and tumorsphere formation assay, respectively. CD133, tumor stem cell drug resistance gene (MDR1 and BCRP1), DNA repair marker (γ-H2AX) and AKT/mTOR/cyclinD1 signaling were measured by Western blot. The relationship between DLGAP1-AS2 and E2F1 was verified using RIP. The interaction between E2F1 and CD151 promoter was confirmed using dual-luciferase reporter gene assay and ChIP. AKT inhibitor API-2 was employed for validating the effect of AKT/mTOR/cyclinD1 signaling in the radioresistance of rectal cancer cells.
The DLGAP1-AS2 level was increased in CD133+ cells after irradiation. DLGAP1-AS2 knockdown inhibited the proliferation, migration and tumorsphere formation while stimulating apoptosis in CD133+ cells. DLGAP1-AS2 inhibition downregulated the expression of CD133, MDR1, BCRP1 and γ-H2AX and suppressed AKT/mTOR/cyclinD1 activation. DLGAP1-AS2 upregulated the expression of CD151 by interacting with E2F1. API-2 neutralized the promotive effects of overexpressed CD151 on radioresistance.
DLGAP1-AS2 accelerates the radioresistance of rectal cancer cells through interactions with E2F1 to upregulate CD151 expression via the activation of the AKT/mTOR/cyclinD1 pathway.
The current study aimed to evaluate the expression and role of miR‐323a in the progression of bladder cancer (BC), thereby providing a theoretical basis and potential therapy methods for BC patients. ...Our data showed that miR‐323a levels were significantly reduced in BC tissues compared with those of non‐cancerous tissues. Meanwhile, miR‐323a was significantly decreased in human BC cell lines (T24, J82, TCCSUP, RT‐112) than that in human normal bladder epithelial cell line SV‐HUC‐1. Furthermore, inhibition of miR‐323a markedly enhanced the migration and invasive capacity of T24 and TCCSUP cells. Moreover, overexpression of miR‐323a significantly prompted the apoptosis of BC cells. Dual luciferase reporter assay and western blot analysis confirmed that c‐Met was a target gene of miR‐323a. More importantly, upregulation of c‐Met significantly prompted BC cell proliferation mainly as a result of the enhanced level of phosphorylation of AKT. This effect could be abolished when c‐Met was silenced in BC cells. In summary, reduced miR‐323a expression in BC contributed to enhanced BC cell proliferation and migration mainly by targeting c‐Met.
Patients who achieve a tumor pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) have better outcomes than patients with residual tumor. However, tumors still recur in the pCR ...patients. Therefore, we aim to explore factors associated with tumor recurrence in this patient population.
A total of 1,913 patients diagnosed with breast cancer between 1995 and 2020 and received NAC were included in this analysis. Clinicopathological data of the patients were retrospectively collected. We used Cox regression analysis to assess the associations of clinicopathological factors with patients' outcome. Proteomic study of tumors was applied to identify differentially expressed proteins (DEPs) between tumors from the pCR patients with tumor recurrence and tumors from those without tumor recurrence. PPI network analysis of the corresponding genes of DEPs was used to identify the hub genes. The prognostic value of the corresponding genes of DEPs was evaluated using two online databases, Kaplan-Meier Plotter and bc-GenExMiner. The genes that were significantly associated with patients' survival in both databases, as well as being identified as hub genes, were considered as potential prognostic markers for pCR patients. Publicly available data from Gene Expression Omnibus (GEO) was used to verify the prognostic value of the identified marker.
Among the 1,913 included patients, 420 had tumor pCR. The median follow-up for the pCR patients was 32.6 months (IQR, 16.3-55.5). Overall estimated 5-year risk of tumor recurrence for the pCR patients was 11%. Multivariable analysis showed that a higher pre-NAC clinical T stage and N stage were independent predictors for increased risk of tumor recurrence (hazard ratio HR 2.57, 95% confidence interval CI 1.01-6.51, P=0.047 for clinical T stage and HR 3.48, 95%CI 1.37-8.83, P=0.009 for clinical N stage). NAC regimens, the type of breast and axillary surgery, and adjuvant chemotherapy were not associated with tumor recurrence. Finally, aldehyde dehydrogenase (ALDH) 3A2 was identified by the proteomic study and was verified as a potential predictor for tumor recurrence in the pCR patients (with a median follow up of 3.78 years for dataset GSE32603 and 2.74 years for dataset GSE25066 from GEO, tumor recurrence rate: low versus high expression, 20.7% versus 4.5% data from GSE32603; 10.9% versus 0% data from GSE25066).
Clinical T stage, clinical N stage and tumor expression of ALDH3A2 were potential markers for predicting tumor recurrence in the pCR patients after NAC.
Abstract
Background
Early prediction of response to neoadjuvant chemotherapy (NAC) is critical in choosing appropriate chemotherapeutic regimen for patients with locally advanced breast cancer. ...Herein, we sought to identify potential biomarkers to predict the response to neoadjuvant chemotherapy for breast cancer patients.
Methods
Three genomic profiles acquired by microarray analysis from subjects with or without residual tumors after NAC downloaded from the GEO database were used to screen the differentially expressed genes (DEGs). An array of public databases, including ONCOMINE, cBioportal, Breast Cancer Gene Expression Miner v4.0, and the Kaplan Meir-plotter, etc., were used to evaluate the potential functions, related signaling pathway, as well as prognostic values of FABP7 in breast cancer. Anti-cancer drug sensitivity assay, real-time PCR, flow cytometry and western-blotting assays were used to investigate the function of FABP7 in breast cancer cells and examine the relevant mechanism.
Results
Two differentially expressed genes, including FABP7 and ESR1, were identified to be potential indicators of response to anthracycline and taxanes for breast cancer. FABP7 was associated with better chemotherapeutic response, while ESR1 was associated with poorer chemotherapeutic effectiveness. Generally, the expression of FABP7 was significantly lower in breast cancer than normal tissue samples. FABP7 mainly high expressed in ER-negative breast tumor and might regulate cell cycle to enhance chemosensitivity. Moreover, elevated FABP7 expression increased the percentage of cells at both S and G2/M phase in MDA-MB-231-ADR cells, and decreased the percentage of cells at G0/G1 phase, as compared to control group. Western-blotting results showed that elevated FABP7 expression could increase Skp2 expression, while decrease Cdh1 and p27kip1 expression in MDA-MB-231-ADR cells. In addition, FABP7 was correlated to longer recurrence-free survival (RFS) in BC patients with ER-negative subtype of BC treated with chemotherapy.
Conclusion
FABP7 is a potential favorable biomarker and predicts better response to NAC in breast cancer patients. Future study on the predictive value and detail molecular mechanisms of FABP7 in contribution to chemosensitivity in breast cancer is warranted.
Abstract Tamoxifen resistance presents a prominent clinical challenge in endocrine therapy for hormone sensitive breast cancer. However, the underlying mechanisms that contribute to tamoxifen ...resistance are not fully understood. In this study, we established a tamoxifen resistant MCF-7 cell line (MCF-7-Tam-R) by continuously incubating MCF-7 cells with 4-OH-tamoxifen. We found that melanoma cell adhesion molecule (MCAM/CD146), a unique epithelial-to- mesenchymal transition (EMT) inducer, was significantly up-regulated at both mRNA and protein levels in MCF-7-Tam-R cells compared to parental MCF-7 cells. Mechanistic research demonstrated that MCAM promotes tamoxifen resistance by transcriptionally suppressing ERα expression and activating the AKT pathway, followed by induction of EMT. Elevated MCAM expression was inversely correlated with recurrence-free and distant metastasis-free survival in a cohort of 4,142 patients with breast cancer derived from a public database, particularly in the subgroup only treated with tamoxifen. These results demonstrate a novel function of MCAM in conferring tamoxifen resistance in breast cancer. Targeting MCAM might be a promising therapeutic strategy to overcome tamoxifen resistance in breast cancer patients.
This paper utilizes experimentally validated Large Eddy Simulation method and the standard Dynamic Mode Decomposition (DMD) analysis technique to investigate the unsteady flow characteristics on a ...compressor cascade under two Reynolds number (Re) conditions (1.1 × 106 in ground state and 8.0 × 104 in high altitude state). The results demonstrate that at low Re, large-scale vortices are formed on the surface of compressor blades, exhibiting a stable rotating state and dominating the flow. Kelvin-Helmholtz instability serves as the determining factor, inducing chaotic and unstable behavior in the separation shear layer, leading to turbulence. Furthermore, DMD modal decomposition reveals a dominant mode at low Re, gradually amplifying and significantly contributing to the overall flow field, while showing strong correlations with other major modes. Conversely, at high Re, vortices on the blade surface become dispersed and smaller, resulting in intricate interactions between vortices of different scales. Harmonic instability, alongside Kelvin-Helmholtz instability, plays a significant role in accelerating boundary layer transition, heightening flow complexity and instability. Additionally, pronounced interaction and energy transfer between different modes occur at high Re, yielding a relatively balanced energy distribution. These findings have important implications for optimizing blade design and enhancing compressor performance by providing a deeper understanding of vortex dynamics and dynamic modal characteristics in the compressor blade flow field.
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