Down-regulating GRP78 reverses pirarubicin resistance of triple negative breast cancer by miR-495-3p mimics and involves the p-AKT/mTOR pathway.

Due to the lack of known therapeutic targets for triple-negative breast cancer (TNBC), chemotherapy is the only available pharmacological treatment. Pirarubicin (tetrahydropyranyl Adriamycin, THP) is the most commonly used anthracycline chemotherapy agent. However, TNBC has a high recurrence rate after chemotherapy, and the mechanisms of chemoresistance and recurrence are not entirely understood. To study the chemoresistance mechanisms, we first screened compounds on a pirarubicin-resistant cell line (MDA-MB-231R) derived from MDA-MB-231. The drug resistance index of MDA-MB-231R cells was approximately five times higher than that of MDA-MB-231 cells. MDA-MB-231R cells have higher GRP78 and lower miR-495-3p expression levels than MDA-MB-231 cells. Transfecting MDA-MB-231R cells with a siGRP78 plasmid reduced GRP78 expression, which restored pirarubicin sensitivity. Besides, transfecting MDA-MB-231R cells with miR-495-3p mimics increased miR-495-3p expression, which also reversed pirarubicin chemoresistance. Cell counting kit-8 (CCK-8), EdU, wound healing, and Transwell assays showed that the miR-495-3p mimics also inhibited cell proliferation and migration. Based on our results, miR-495-3p mimics could down-regulate GRP78 expression via the p-AKT/mTOR signaling pathway in TNBC cells. Remarkably, chemo-resistant and chemo-sensitive TNBC tissues had opposite trends in GRP78 and miR-495-3p expressions. The lower the GRP78 and the higher the miR-495-3p expression, the better prognosis in TNBC patients. Therefore, the mechanism of pirarubicin resistance might involve the miR-495-3p/GRP78/Akt axis, which would provide a possible strategy for treating TNBC.

Radiosensitizer EXO-miR-197-3p Inhibits Nasopharyngeal Carcinoma Progression and Radioresistance by Regulating the AKT/mTOR Axis and HSPA5-mediated Autophagy.

The biological functions of exosomes and microRNAs (miRs) in nasopharyngeal carcinoma (NPC) remain largely unexplored. Here, miR-197-3p was screened and identified, and whose level was reduced in serum and exosomes of patients with NPC. MiR-197-3p might be a good diagnostic and prognostic indicator. Our data showed that miR-197-3p expression was closely related to radioresistance, apoptosis, proliferation, migration, and survival of NPC. Inhibition of miR-197-3p expression in vitro could promote the proliferation and migration of NPC cells, while promotion of miR-197-3p expression in vivo could significantly inhibit the growth and enhance the radiosensitivity of NPC cells. From the perspective of mechanism, miR-197-3p could inhibit AKT/mTOR phosphorylation activation, inhibit an activated pathway of AKT/mTOR, target Heat Shock 70-kDa Protein 5(HSPA5) related to endoplasmic reticulum homeostasis, inhibit HSPA5-mediated autophagy, and reverse the radioresistance of NPC. Interestingly, exosomal miR-197-3p (EXO-miR-197-3p) reduced the proliferation and migration potential of NPC cells in vitro, and tumor growth and radioresistance of NPC cells in vivo. EXO-miR-197-3p inhibited NPC progression and radioresistance by regulating AKT/mTOR phosphorylation activation and HSPA5-mediated autophagy. In conclusion, our results highlight the potential of EXO-miR-197-3p as an effective radiosensitizer and therapeutic agent for refractory NPC.

Long-Term Tracking of Cancer Cell Nucleus and Identification of Colorectal Cancer with an Aggregation-Induced Emission-Based Fluorescent Probe.

In clinical diagnosis and treatment, it is very important to distinguish cancer cells from normal cells. Nuclear-selective fluorescent probe that specifically target tumors can not only make the difference in assessing tumor margins during surgery and then facilitating accurate resection of the tumor, but also can provide crucial biomedical information of tumor progress if it can be used for long-term dynamic visualization of nucleus in cancer. Herein, a novel fluorescent probe 3 was designed and characterized to be of low-toxicity and water-solubility. The biological evaluation indicated that probe 3 prefers nucleic acids rather than accumulation in non-neuclear sites while superior to the commercial available agent DAPI (4',6-diamidino-2-phenylindole), in terms of its character of aggregation-induced emission (AIE), large Stokes shift (175 nm) and light stability. Further experiments demonstrated that probe 3 can not only differentiate SW480 and SW620 (cancer cells) from GES-1 (normal cells) with high contrast (dyed in nuclear of cancer cells and not in nuclear of normal cells), but also used for tracking cancer cell nuclear for long time. Furthermore, 3D reconstruction fluorescence imaging proved that probe 3 was able for identifying colorectal cancer tissues from para-carcinoma tissues by a strong contrast. Therefore, in precise surgery of colorectal cancer, probe 3 may be a promising-agent for guiding of intraoperation.

miR­495 enhances the efficacy of radiotherapy by targeting GRP78 to regulate EMT in nasopharyngeal carcinoma cells.

Glucose­regulated protein 78 (GRP78) was revealed to be associated with the radioresistance of nasopharyngeal carcinoma (NPC) in our previous study. GRP78 is a highly expressed cell surface protein, and holds great promise as a cancer specific target. Its expression may be impacted by the regulation of miRNAs, which may be involved in the radioresistance of NPC. A better understanding of the mechanisms of radioresistance may generate new targets of therapy for NPC patients. The present study was designed to investigate the effect of microRNA targeting GRP78 on the radiosensitivity of NPC. First, we used miRWalk software to predict miRNAs that may interact with GRP78. Subsequently, analysis of miR­495 and GRP78 expression was performed in the primary tissues of 92 NPC tissues and cell lines by immunohistochemistry and real­time PCR and the results revealed that miR­495 expression was lower in radioresistant NPC tissues in comparison to chronic rhinitis tissues, and also lower in radioresistant 5­8F cells (5­8F­IR) in comparison to its parental 5­8F cells. Notably, we observed an inverse association between the expression miR­495 and GRP78. Our bioinformatics analysis led to the identification of miR­495 as the optimal miRNA interacting with GRP78 mRNA. Furthermore, miR­495 targeting the 3'untranslated region (UTR) of GRP78 was detected by a Dual­Glo Luciferase Assay system. Finally, we observed that miR­495 inhibition led to a significant increase in the radioresistance of 5­8F cells and higher GRP78 expression, which may be involved in epithelial­mesenchymal transition (EMT) phenotype. miR­495 targeted the 3'UTR of GRP78 and contributed to the efficacy of radiation therapy in NPC.

Down-Regulated miR-125a-5p Promotes the Reprogramming of Glucose Metabolism and Cell Malignancy by Increasing Levels of CD147 in Thyroid Cancer.

BACKGROUND: CD147 contributes to increased aerobic glycolysis through which it promotes tumor growth. Accumulating evidence suggests that CD147 exerts a variety of functions in thyroid cancer (TC) progression but the molecular mechanisms and therapeutic value of CD147 remain unclear. METHODS: CD147 levels in TC tissues were analyzed to assess its relationship with prognosis and disease progression. A microRNA (miRNA) microarray and bioinformatics approach were used to identify microRNA regulators of CD147 through measurement of the expression and functions of these miRNAs in TC tissues and cell lines. Precursor miRNA-transfected cells were used to assess regulation of CD147 by miRNA. The effect of miRNA on TC cells via inhibition of glycolysis through CD147 targeting was also evaluated. RESULTS: We found that miR-125a-5p regulates CD147 and is negatively correlated with its expression and function. Moreover, CD147 knockdown or increased miR-125a-5p expression significantly reduced the viability, migration, and invasion of TC cells. Our mechanistic studies demonstrate that, through directly repressing the expression of the CD147 protein, miR-125a-5p suppresses aerobic glycolysis and lactate production and subsequently reduces TC cell viability, migration, and invasion, thereby exerting tumor suppressor functions. CONCLUSIONS: The novel connection identified between miR-125a-5p and CD147 suggests a new diagnostic and prognostic role for miR-125a-5p and that CD147 inhibition may be a candidate therapeutic target in the therapy of for TC.

A self-assembled nanoprobe for long-term cancer cell nucleus-specific staining and two-photon breast cancer imaging.

Herein, a novel self-assembled nanoprobe for the long-term tracking of the nucleoli of cancer cells and for differentiating between clinical breast cancer tissues and para-carcinoma tissues has been developed.

Triptolide inhibits cell growth and GRP78 protein expression but induces cell apoptosis in original and radioresistant NPC cells.

The radioresistance is the key factor to hamper curative effect and survival of nasopharyngeal carcinoma (NPC) patients. Nature triptolide (TPL) has been found to circumvent drug-resistant effect of cancer, but its effect on NPC radioresistance has been rarely studied. In the present study, the 10 Gy-resistant CNE2 subclones (CNE2-SR) were used as a NPC radioresistant model. The IC50 of TPL in CNE2 and CNE2-SR cells was measured by MTT assay, cell cycle was analyzed by flow cytometry, and protein expression was examined by western blot. Our data showed that TPL treatment decreased the percentage of viable cells, and IC50 value in CNE2 and CNE2-SR cells was 23.6 ± 1.41 nmol/L and 31.2 ± 1.16 nmol/L, respectively. Six Gy was a moderate dosage of X-ray for CNE2, and 25 nM TPL was close to IC50 value of CNE2 and CNE2-SR. Six Gy X-ray and/or 25 nM TPL significantly inhibited tumor growth in nude mice. Furthermore, 6 Gy X-ray and/or 25 nM TPL significantly inhibited cell growth and induced cell apoptosis and M/G2 phase arrest in CNE2 and CNE2-SR cells. Moreover, TPL treatment significantly inhibited the expression of GRP78 protein in CNE2 and CNE2-SR cells. These results suggest that TPL may serve as a potential radiosensitizer agent for NPC treatment.