Effect of long noncoding RNA CCAT2 on drug sensitivity to 5-fluorouracil of breast cancer cells through microRNA-145 meditated by p53.

The current study was set out to investigate the mechanism by which silenced long noncoding RNA (lncRNA) colon cancer-associated transcript 2 (CCAT2) modulates the cell growth, migration, invasion, and drug sensitivity of breast cancer (BC) cells to 5-fluorouracil (5-Fu) with the involvement of miR-145 and p53. First, high CCAT2 expression was presented in BC cells and tissues. Subsequently, the links between CCAT2 expression and BC clinicopathological features were analyzed. Highly-expressed CCAT2 was linked to lymph node metastasis, positive progesterone receptor, estrogen receptor, and Ki-67 of BC cells. Then, the gain- and loss-of-function approaches were performed to measure the regulatory role of CCAT2 in the biological processes of BC cells. Silencing of CCAT2 suppressed in vitro cell growth, proliferation, invasion, migration abilities, and epithelial-mesenchymal transformation, increased cell apoptosis, and enhanced drug sensitivity of BC cells. Silencing of CCAT2 upregulated miR-145, which was poorly expressed in drug-resistant BC cells. p53 can bind to the miR-145 promoter region and increase miR-145 expression. Upregulation of miR-145 induced by silencing of CCAT2 can be invalidated by p53-siRNA. To conclude, p53-induced activation of miR-145 could be inhibited by CCAT2, while overexpression of CCAT2 could improve the drug resistance of BC cells to 5-Fu.

Extracellular Vesicles Carrying miR-887-3p Promote Breast Cancer Cell Drug Resistance by Targeting BTBD7 and Activating the Notch1/Hes1 Signaling Pathway.

Objective: Chemoresistance remains the primary reason threatening the prognosis of breast cancer (BC) patients. Extracellular vesicles (EVs) contribute to chemoresistance by carrying microRNAs (miRNAs). This study investigated the mechanism of miR-887-3p mediated by EVs in BC cell drug resistance. Methods: MDA-MB-231-derived EVs were extracted and identified. BC cells were treated with different concentrations of doxorubicin, cisplatin, and fulvestrant, and the cell survival was evaluated. PKH26-labeled EVs were cocultured with BC cells, and the uptake of EVs was observed. miR-887-3p expression in BC cells and EVs was detected. After silencing miR-887-3p in MDA-MB-231 cells, BC cells were treated with EV-inhi to observe drug resistance. The target gene of miR-887-3p was predicted and verified. The levels of downstream Notch1/Hes1 pathway were detected. Xenograft experiment was conducted to evaluate the effect of EVs on the growth and drug resistance in vivo. Results: MDA-MB-231-derived EVs enhanced the drug resistance of BC cells. EVs carried miR-887-3p into BC cells. miR-887-3p expression was elevated in BC cells and EVs. miR-887-3p inhibition reduced the drug resistance of BC cells. miR-887-3p targeted BTBD7. Overexpression of BTBD7 partially reversed the drug resistance of BC cells caused by EV treatment. EV treatment increased the level of Notch1/Hes1, and overexpression of BTBD7 decreased the level of Notch1/Hes1. In vivo experiments further validated the results of in vitro experiments. Conclusion: EVs carrying miR-887-3p could target BTBD7 and activate the Notch1/Hes1 signaling pathway, thereby promoting BC cell drug resistance. This study may offer novel insights into BC treatment.

Long noncoding RNA CCAT2 reduces chemosensitivity to 5-fluorouracil in breast cancer cells by activating the mTOR axis.

Breast cancer (BC) is the most prevalent cancer in women and the second leading cause for cancer-related death in women. LncRNA CCAT2 is involved in BC cell drug sensitivity. Drug resistance of BC cells after chemotherapy is the main obstacle to therapeutic effects. This study explored whether BC cell drug sensitivity to 5-Fu was related to lncRNA CCAT2-regulated mTOR pathway. Normal breast tissues and BC tissues before/after neoadjuvant chemotherapy were collected, and CCAT2 expression was detected by RT-qPCR. Correlation between CCATA2 expression and neoadjuvant chemotherapy efficacy was analysed using the Kendall's tau-b correlation analysis. Normal breast epithelial cells and BC cell lines were cultured. BC cell lines were treated with 5-Fu, and CCAT2 mRNA level in cells was detected. The 5-Fu-resistant MCF-7/5-Fu and MDA-MB-231/5-Fu cells were treated with CCAT2 overexpression/knockdown or CCI-779 (the mTOR pathway inhibitor). The mTOR pathway levels were detected. Expression of apoptosis-related factors was identified. A subcutaneous xenograft model was carried out. High CCAT2 expression was detected in BC tissues and BC drug-resistant cells after neoadjuvant chemotherapy, and a negative link was revealed between CCAT2 expression and efficacy of neoadjuvant chemotherapy. p-mTOR/mTOR in 5-Fu-resistant BC cells with inhibited CCAT2 was decreased, while CCAT2 overexpression activated the mTOR pathway. IC50 value, proliferation, cells in S phase increased and apoptosis reduced after CCAT2 overexpression. After si-CCAT2 or CCI-779 treatment, the growth rate of transplanted tumours was inhibited, while promoted after CCAT2 overexpression. CCAT2 may reduce BC cell chemosensitivity to 5-Fu by activating the mTOR pathway.

The effects of fructose diphosphate on routine coagulation tests in vitro.

To evaluate the effects of fructose diphosphate (FDP) on routine coagulation tests in vitro, we added FDP into the mixed normal plasma to obtain the final concentration of 0, 1, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30 and 35 mg/mL of drug. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (FBG) and thrombin time (TT) of samples were analyzed with blood coagulation analyzers from four different manufacturers(Sysmex, Stago, SEKISUI and Werfen) and their corresponding reagents, respectively. Before the experiment, we also observed whether there were significant differences in coagulation test results of different lots of reagents produced by each manufacturer. At the same time as the four routine clotting tests, the Sysmex blood coagulation analyzer and its proprietary analysis software were used to detect the change of maximum platelet aggregation rate in platelet-rich plasma after adding FDP (0, 1, 2, 3, 4, 5 and 6 mg/mL). The results of PT, aPTT and TT showed a FDP (0-35 mg/mL) concentration-dependent increase and a FBG concentration-dependent decrease. The degree of change (increase or decrease) varied depending on the assay system, with PT and aPTT being more affected by the Sysmex blood coagulation testing instrument reagent system and less affected by CEKISUI, TT less affected by CEKISUI and more affected by Stago, and FBG less affected by Stago and more affected by Sysmex. The results of PT, aPTT and TT were statistically positively correlated with their FDP concentrations, while FBG was negatively correlated. The correlation coefficients between FDP and the coagulation testing systems of Sysmex, Stago, Werfen and SEKISUI were 0.975, 0.988, 0.967, 0.986 for PT, and 0.993, 0.989, 0.990 and 0.962 for aPTT, 0.994, 0.960, 0.977 and 0.982 for TT, - 0.990, - 0.983, - 0.989 and - 0.954 for FBG, respectively. Different concentrations of FDP (0, 1, 2, 3, 4, 5 and 6 mg/mL) had different effects on the maximum aggregation rate of platelet induced by the agonists of adenosine diphosphate (ADP, 5 µmol/L), arachidonic acid (Ara, 1 mmol/L), collagen (Col, 2.5 µg/mL) and epinephrine (Epi,10 µmol/L), but the overall downward trend was consistent, that is, with the increase of FDP concentration, the platelet aggregation rate decreased significantly. Our experimental study demonstrated a possible effect of FDP on the assays of coagulation and Platelet aggregation, which may arise because the drug interferes with the coagulation and platelet aggregation detection system, or it may affect our in vivo coagulation system and Platelet aggregation function, the real mechanism of which remains to be further verified and studied.

Retraction notice to "Downregulation of lncRNA GAS5 confers tamoxifen resistance by activating miR-222 in breast cancer" [Canc. Lett. 434 (2018) 1-10].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Upon investigation, it was discovered that 5 figures contain fabrication. Figures 1C, 3D, 5C, 5D, and 6G contain manipulated and/or duplicated data. The authors requested a corrigendum be published, however, due to the large number of corrections applied (Figs. 3, 6, 7, 8 and S3), it cannot be concluded that these changes would not alter the conclusions of the paper. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Long non-coding RNA NEAT1 transported by extracellular vesicles contributes to breast cancer development by sponging microRNA-141-3p and regulating KLF12.

OBJECTIVE: Breast cancer (BC) remains a public-health issue on a global scale. Long non-coding RNAs (lncRNAs) play functional roles in BC. This study focuses on effects of NEAT1 on BC cell invasion, migration and chemotherapy resistance via microRNA (miR)-141-3p and KLF12. METHODS: After extraction and identification of serum extracellular vesicles (EVs), NEAT1 expression in EVs was detected and its association with clinical characteristics of BC patients was analyzed. Besides, the gain-of function was performed to investigate the roles of NEAT1 and miR-141-3p in BC, and levels of NEAT1, miR-141-3p, KLF12 and MDR1 after EV treatment were detected by RT-qPCR and Western blot analysis. Furthermore, the in vitro findings were confirmed via lung metastases in nude mice. RESULTS: NEAT1 expression in serum EVs was high and related to lymph node metastasis, progesterone receptor, estrogen receptor and Ki-67 in BC patients. After EV treatment, NEAT1 and KLF12 levels were increased, miR-141-3p expression was decreased, the abilities of proliferation, invasion, migration and in vivo metastasis were enhanced, and the sensitivity of cells to cisplatin, paclitaxel and 5-fluorouracil was decreased. After NEAT1 interference, NEAT1 and KLF12 levels in BC cells treated with EVs were decreased, miR-141-3p expression was increased, cell proliferation, invasion, migration and in vivo metastasis were decreased, and drug resistance sensitivity was increased. NEAT1 can bind to miR-141-3p and upregulates KLF12 expression. CONCLUSIONS: EVs inhibit the regulation of KLF12 by miR-141-3p by transporting NEAT1 to BC cells, thus promoting BC cell invasion, migration, and chemotherapy resistance.

Downregulated exosomal microRNA-148b-3p in cancer associated fibroblasts enhance chemosensitivity of bladder cancer cells by downregulating the Wnt/ß-catenin pathway and upregulating PTEN.

OBJECTIVE: Exosomes derived from cancer-associated fibroblasts (CAFs) are known as important drivers of tumor progression. Previously, microRNA (miR)-148b-3p has been found to be upregulated in bladder cancers as well as in body fluids (blood, urine) of bladder cancer patients. Here, we aimed to explore the role of CAF-derived exosome miR-148b-3p in bladder cancer progression and chemosensitivity. METHODS: Transwell, MTT, flow cytometry and colony formation assays were applied to assess the effects of CAF-derived exosomes on bladder cancer cell metastasis, epithelial-mesenchymal transition (EMT) and chemosensitivity. A dual luciferase reporter assay was employed to evaluate the targeting relationship between miR-148b-3p and PTEN. Gain- and loss- of function assays were conducted to explore the roles of miR-148b-3p and PTEN in the behavior of bladder cancer cells. The role of PTEN in the metastasis, EMT and chemosensitivity of bladder cancer cells was assessed both in vivo and in vitro. RESULTS: We found that CAF-derived exosomes promoted the metastasis, EMT and drug resistance of bladder cancer cells. We also found that CAF-derived exosomes could directly transport miR-148b-3p into bladder cancer cells. In a xenograft mouse model we found that CAF-derived exosomes increased miR-148b-3p expression levels and promoted tumor proliferation, metastasis and drug resistance. PTEN was validated as a target of miR-148b-3p. Concordantly, we found that PTEN overexpression inhibited EMT, metastasis and chemoresistance in bladder cancer cells, reversing the tumor promoting effects of miR-148b-3p via the Wnt/ß-catenin pathway. CONCLUSIONS: Our results suggest that miR-148b-3p downregulation in CAF-derived exosomes, thereby inhibiting the Wnt/ß-catenin pathway and promoting PTEN expression, may offer potential opportunities for bladder cancer treatment.

Cancer-associated fibroblast-secreted exosomal miR-423-5p promotes chemotherapy resistance in prostate cancer by targeting GREM2 through the TGF-ß signaling pathway.

Therapeutic failure in prostate cancer (PC) is believed to result from its unusually invasive and metastatic nature. Cancer-associated fibroblasts (CAFs) are essential in the tumor microenvironment. We intended to study the role of CAF-derived exosomes in the context of PC and the potential regulatory mechanism associated with miR-423-5p and GREM2. CAF-derived exosomes decreased the chemosensitivity of parental PC cells and enhanced the drug resistance of drug-resistant cells. PC-associated fibroblast-derived exosomes carrying miR-423-5p increased the resistance of PC to taxane by inhibiting GREM2 through the TGF-ß pathway. Inhibition of the TGF-ß pathway partially reversed the increased drug resistance in PC cells induced by CAF-derived exosomes. Inhibition of miR-423-5p enhanced the drug sensitivity of PC cells in vivo. We showed that CAF-secreted exosomal miR-423-5p promoted chemotherapy resistance in PC by targeting GREM2 through the TGF-ß pathway. This study may allow the development of novel approaches for PC.

LINC00160 mediated paclitaxel-And doxorubicin-resistance in breast cancer cells by regulating TFF3 via transcription factor C/EBPß.

Chemoresistance represents a major challenge in breast cancer (BC) treatment. This study aimed to probe the roles of LINC00160 in paclitaxel- and doxorubicin-resistant BC cells. Three pairs of BC and adjacent normal tissue were used for lncRNA microarray analysis. Paclitaxel-resistant MCF-7 (MCF-7/Tax) and doxorubicin-resistant BT474 (BT474/Dox) cells were generated by exposure of parental drug-sensitive MCF-7 or BT474 cells to gradient concentrations of drugs. Correlation between LINC00160 expression and clinical response to paclitaxel in BC patients was examined. Short interfering RNAs specifically targeting LINC00160 or TFF3 were designed to construct LINC00160- and TFF3-depleted BC cells to discuss their effects on biological episodes of MCF-7/Tax and BT474/Dox cells. Interactions among LINC00160, transcription factor C/EBPß and TFF3 were identified. MCF-7/Tax and BT474/Dox cells stable silencing of LINC00160 were transplanted into nude mice. Consequently, up-regulated LINC00160 led to poor clinical response to paclitaxel in BC patients. LINC00160 knockdown reduced drug resistance in MCF-7/Tax and BT474/Dox cells and reduced cell migration and invasion. LINC00160 recruited C/EBPß into the promoter region of TFF3 and increased TFF3 expression. LINC00160-depleted MCF-7/Tax and BT474/Dox cells showed decreased tumour growth rates in nude mice. Overall, we identified a novel mechanism of LINC00160-mediated chemoresistance via the C/EBPß/TFF3 axis, highlighting the potential of LINC00160 for treating BC with chemoresistance.

Silencing CDR1as enhances the sensitivity of breast cancer cells to drug resistance by acting as a miR-7 sponge to down-regulate REGγ.

In our study, we aimed to investigate the role of CDR1as during competitive inhibition of miR-7 in the regulation of cisplatin chemosensitivity in breast cancer via regulating REGγ. RT-qPCR was applied to detect the expression of CDR1as and miR-7 in breast cancer tissues, breast cancer cell lines and corresponding drug-resistant cell lines. The correlation between CDR1as and miR-7 and between miR-7 and REGγ was evaluated. MCF-7-R and MDA-MB-231-R cells were selected followed by transfection of a series of mimics, inhibitors or siRNA. The effect of CDR1as on the half maximal inhibitor concentration (IC50), cisplatin sensitivity and cell apoptosis was also analysed. Furthermore, a subcutaneous xenograft nude mouse model was established to further confirm the effect of CDR1as on the chemosensitivity of breast cancer to cisplatin in vivo. Immunohistochemical staining was conducted to test the Ki-67 expression in nude mice. A positive correlation was found between the drug resistance and CDR1as expression in breast cancer. CDR1as could increase the resistance of breast cancer cells to cisplatin. miR-7 expression was low, while REGγ was highly expressed in MCF-7-R and MDA-MB-231-R cells. CDR1as competitively inhibited miR-7 and up-regulated REGγ. Overexpression of miR-7 could reverse the enhanced sensitivity of silenced CDR1as to drug-resistant breast cancer cells. Additionally, in vivo experiments demonstrated that CDR1as mediated breast cancer occurrence and its sensitivity to cisplatin. Silencing CDR1as decreased Ki-67 expression. Silencing CDR1as may inhibit the expression of REGγ by removing the competitive inhibitory effect on miR-7 and thus enhancing the sensitivity of drug-resistant breast cancer cells.

Altered circulating levels of adipokine omentin-1 in patients with prostate cancer.

Background: Prostate cancer (PCa), one of the most common cancers in men, accounts for nearly 20% of adult malignant neoplasms. Omentin-1 is synthesized in visceral adipose tissue and its concentration in plasma changes with cancers. However, the association between omentin-1 and PCa was rarely studied. Thus, we investigated the plasma omentin-1 levels in PCa patients in Chinese population. Materials and methods: Ninety cases of PCa and 90 matched healthy controls were enrolled in this study. We used ELISA technique to determine the concentration of omentin-1. Results: The concentration of omentin-1 was higher in patients with PCa compared to controls (P<0.001). Additionally, positive correlations were uncovered between omentin-1 with body mass index (r=0.240, P=0.001), waist-hip ratio (r=0.228, P=0.002), and prostate-specific antigen (r=0.589, P<0.001). Receiver operating characteristic curve analysis indicated that plasma omentin-1 differentiated PCa patients from controls with a sensitivity of 85.9% and a specificity of 83.7%. Conclusion: Our study demonstrated that the levels of plasma omentin-1 were increased in PCa patients. Meanwhile, omentin-1 may be a possible biomarker for diagnosing PCa. For validation, more studies should focus on and elucidate the potential mechanism underlying this change.

Inhibition of circular RNA CDR1as increases chemosensitivity of 5-FU-resistant BC cells through up-regulating miR-7.

This study aims to explore the mechanism of Circular RNA CDR1as implicating in regulating 5-fluorouracil (5-FU) chemosensitivity in breast cancer (BC) by competitively inhibiting miR-7 to regulate CCNE1. Expressions of CDR1as and miR-7 in 5-FU-resistant BC cells were determined by RT-PCR. CCK-8, colony formation assay and flow cytometry were applied to measure half maximal inhibitory concentration (IC50), 5-Fu chemosensitivity and cell apoptosis. Western blot was used to detect the expressions of apoptosis-related factors. CDR1as was elevated while miR-7 was inhibited in 5-FU-resistant BC cells. Cells transfected with si-CDR1as or miR-7 mimic had decreased IC50 and colony formation rate, increased expressions of Bax/Bcl2 and cleaved-Caspase-3/Caspase-3, indicating inhibition of CDR1as and overexpression of miR-7 enhances the chemosensitity of 5-FU-resistant BC cells. Targetscan software indicates a binding site of CDR1as and miR-7 and that CCNE1 is a target gene of miR-7. miR-7 can gather CDR1as in BC cells and can inhibit CCNE1. In comparison to si-CDR1as group, CCNE1 was increased and chemosensitivity to 5-Fu was suppressed in si-CDR1as + miR-7 inhibitor group. When compared with miR-7 mimic group, CDR1as + miR-7 mimic group had increased CCNE1 and decreased chemosensitivity to 5-Fu. Nude mouse model of BC demonstrated that the growth of xenotransplanted tumour in si-CDR1as + miR-7 inhibitor group was faster than that in si-CDR1as group. The tumour growth in CDR1as + miR-7 mimic group was faster than that in miR-7 mimic group. CDR1as may regulate chemosensitivity of 5-FU-resistant BC cells by inhibiting miR-7 to regulate CCNE1.

Effect of the LncRNA GAS5-MiR-23a-ATG3 Axis in Regulating Autophagy in Patients with Breast Cancer.

BACKGROUND/AIMS: An increasing body of evidence shows that long noncoding RNAs (lncRNAs) are involved in many different cancers. In this study, we aimed to investigate the competing endogenous RNA (ceRNA)-dependent mechanism by which the lncRNA GAS5 contributes to the development of breast cancer. METHODS: A total of 68 breast cancer patients were enrolled, and breast cancer and adjacent normal tissues were collected. The human breast cancer cell lines MDA-MB-231, MDA-MB-453, BT549, SK-BR-3 and MCF-7 and human breast cell line MCF10A were utilized in this study. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were performed to detect expression of relative factors. RNA immunoprecipitation (RIP) was used to evaluate the relationship between GAS5 and miR-23a, and a dual luciferase reporter gene assay was employed to assess the relationship between ATG3 and miR-23a. A subcutaneous xenograft nude mouse model was generated to examine the role of GAS5 and its regulatory pathway in autophagy. RESULTS: GAS5 levels were frequently decreased in breast cancer tissues and cell lines, and its relatively low expression was closely related to a larger tumour size, advanced tumour-node-metastasis (TNM) stage and estrogen receptor-negative (ER-) breast cancer tissues. More importantly, we found that GAS5 promoted autophagy, with enhanced autophagosome formation after GAS5 overexpression. GAS5 was found to act as a microRNA sponge in a pathway that included miR-23a and its target gene ATG3. The GAS5-miR-23a-ATG3 axis significantly regulated autophagy in vivo and in vitro. CONCLUSIONS: In summary, we report that the GAS5-miR-23a-ATG3 axis can be regarded as a key regulator of autophagy pathways in breast cancer; it may constitute a promising biomarker and therapeutic target in the future.

RETRACTED: Downregulation of lncRNA GAS5 confers tamoxifen resistance by activating miR-222 in breast cancer.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Upon investigation, it was discovered that 5 figures contain fabrication. Figures 1C, 3D, 5C, 5D, and 6G contain manipulated and/or duplicated data. The authors requested a corrigendum be published, however, due to the large number of corrections applied (figures 3, 6, 7, 8 and S3), it cannot be concluded that these changes would not alter the conclusions of the paper. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

ADAM12-L confers acquired 5-fluorouracil resistance in breast cancer cells.

5-FU-based combinatory chemotherapeutic regimens have been routinely used for many years for the treatment of breast cancer patients. Recurrence and chemotherapeutic drug resistance are two of the most prominent factors that underpin the high mortality rates associated with most breast cancers (BC). Increasing evidence indicates that overexpression of ADAMs could correlate with cancer progression. However, the role of ADAMs in the chemoresistance of cancer cells has rarely been reported. In this study, we observed that 5-FU induces expression of the ADAM12 isoform ADAM12-L but not ADAM12-S in BC cells and in recurrent BC tissues. The overexpression of ADAM12-L in BC cells following 5-FU treatment results in the acquisition of resistance to 5-FU. ADAM12-L overexoression also resulted in increased levels of p-Akt but not p-ERK. These alterations enhanced BC cell growth and invasive abilities. Conversely, ADAM12 knockdown attenuated the levels of p-Akt and restored 5-FU sensitivity in 5-FU-resistant BC cells. ADAM12 knockdown also reduced BC cell survival and invasive abilities. These findings suggest that ADAM12-L mediates chemoresistance to 5-FU and 5-FU-induced recurrence of BC by enhancing PI3K/Akt signaling. The results of this study suggest that specific ADAM12-L inhibition could optimize 5-FU-based chemotherapy of BC, thereby preventing BC recurrence in patients.