MiR-21 is a Predictor for Chemoradioresistance and a Novel Therapeutic Target in Head and Neck Squamous Cell Carcinoma

ObjectiveThis study aimed to clarify whether circulating miR-21 represents a predictive biomarker in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy, and to investigate the effect of miR-21 inhibitor for chemoradiation in human SCC cells.MethodsPlasma samples were obtained from 22 patients with HNSCC and 25 non-cancer volunteers. Plasma miR-21 expression was measured using real-time quantitative reverse transcription polymerase chain reaction. The effects of miR-21 inhibitor in human SCC cells were investigated by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and Western blot analysis.ResultsPlasma miR-21 expression was higher in HNSCC patients than in control patients (p< 0.001). Seven patients with recurrence showed significantly higher plasma miR-21 than the 15 patients without recurrence. Moreover, miR-21 inhibition significantly enhanced cisplatin- or radiation-induced apoptosis. Western blot analysis suggested the programmed cell death 4 (PDCD4) protein as a potential target of miR-21 in relation to apoptosis. Adding miR-21 inhibition to radiation or cisplatin treatment provided clear and potent suppression of tumor cell proliferation.ConclusionThis study provides new insights into the role of miR-21 as a predictive biomarker for HNSCC treated with chemoradiotherapy, and suggests a potential target to improve the effects of chemoradiotherapy against HNSCC.

The brain targeted delivery of programmed cell death 4 specific siRNA protects mice from CRS-induced depressive behavior

Depression is one of the most common psychiatric disorders. Recently, studies demonstrate that antidepressants generating BDNF not only maintain synaptic signal transmission but also repress neuroinflammatory cytokines such as IL-6 and IL-1β. Therefore, promoting BDNF expression provides a strategy for the treatment of depression. Our recent research has indicated that programmed cell death 4 (Pdcd4) is a new target for antidepressant treatment by facilitating BDNF. Herein, we modified Pdcd4 specific small interfering RNA (siPdcd4) with the rabies virus glycoprotein peptide (RVG/siPdcd4) which enables it cross the blood-brain barrier (BBB). We found that RVG/siPdcd4 complex was selectively delivered to neurons and microglia and silenced the expression of Pdcd4, thereby up-regulating the level of BDNF and down-regulating IL-6 and IL-1β expression. More importantly, RVG/siPdcd4 injection attenuated synaptic plasticity impairment and protected mice from CRS-induced depressive behavior. These findings suggest that RVG/siPdcd4 complex is a potential therapeutic medicine for depression.

Induction of PDCD4 by albumin in proximal tubule epithelial cells potentiates proteinuria-induced dysfunctional autophagy by negatively targeting Atg5

The precise molecular mechanism of autophagy dysfunction in type 1 diabetes is not known. Herein, the role of programmed cell death 4 (PDCD4) in autophagy regulation in the pathogenesis of diabetic kidney disease (DKD) in vivo and in vitro was described. It was found that Pdcd4 mRNA and protein was upregulated in the streptozotocin (STZ)-induced DKD rats. In addition, a unilateral ureteral obstruction mouse model displayed an upregulation of PDCD4 in the disease group. kidney biopsy samples of human DKD patients showed an upregulation of PDCD4. Furthermore, western blotting of the STZ-induced DKD rat tissues displayed a low microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, as compared to the control. It was found that albumin overload in cultured PTEC could upregulate the expression of PDCD4 and p62, and decrease the expression of LC3-II and autophagy-related 5 (Atg5) proteins. The knockout of Pdcd4 in cultured PTECs could lessen albumin-induced dysfunctional autophagy as evidenced by the recovery of Atg5 and LC3-II protein. The forced expression of PDCD4 could further suppress the expression of crucial autophagy-related gene Atg5. Herein, endogenous PDCD4 was shown to promote proteinuria-induced dysfunctional autophagy by negatively regulating Atg5. PDCD4 might therefore be a potential therapeutic target in DKD.

Clinical Significance of PDCD4 in Melanoma by Subcellular Expression and in Tumor-Associated Immune Cells

Little is known about the subcellular localization and function of programmed cell death 4 (PDCD4) in melanoma. Our past studies suggest PDCD4 interacts with Pleckstrin Homology Domain Containing A5 (PLEKHA5) to influence melanoma brain metastasis outcomes, as high intracranial PDCD4 expression leads to improved survival. We aimed to define the subcellular distribution of PDCD4 in melanoma and in the tumor microenvironment during neoplastic progression and its impact on clinical outcomes. We analyzed multiple tissue microarrays with well-annotated clinicopathological variables using quantitative immunofluorescence and evaluated single-cell RNA-sequencing on a brain metastasis sample to characterize PDCD4+ immune cell subsets. We demonstrate differences in PDCD4 expression during neoplastic progression, with high tumor and stromal PDCD4 levels associated with improved survival in primary melanomas and in intracranial metastases, but not in extracranial metastatic disease. While the expression of PDCD4 is well-documented on CD8+ T cells and natural killer cells, we show that it is also found on B cells and mast cells. PDCD4 expression in the tumor microenvironment is associated with increased immune cell infiltration. Further studies are needed to define the interaction of PDCD4 and PLEKHA5 and to evaluate the utility of this pathway as a therapeutic target in melanoma brain metastasis.

Expression Pattern of MicroRNA-21 during the Liver Ischemia/Reperfusion

Ischemia/reperfusion (I/R) injury in cadaveric liver transplantation is not avoidable. Liver I/R injury is an important phenomenon in hepatic damage. MicroRNA-21 (miR-21) plays an important role in I/R injury. The present study aimed to determine the expression pattern of miR-21 in liver I/R injury/recovery and its correlation with the immunologic transmission signals pathways in several days post-reperfusion. In an animal model for I/R in the liver, 40 male Balb/c mice were divided into 3 groups. The animals were monitored for 3 and 24 hours, and also for 4, 7, 14, and 28 days postreperfusion. Liver tissue damage was assessed by histopathology. The plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total antioxidant capacity (TAC) levels were measured with enzymatic assays. MiR-21, programmed cell death 4 (PDCD4) mRNA, T-cell-restricted intracellular antigen 1 (TIA1) mRNA, and fas ligand (FASL) mRNA expression levels were measured; using reverse transcription-polymerase chain reaction (RT-PCR) at different times after the reperfusion in liver tissue and blood. Histopathology and plasma ALT, AST, ALP, and TAC levels confirmed liver damage induced by I/R injury. MiR-21 increased by twofold in the liver tissue and on the inflammatory phase after 24 hours of reperfusion; it then continued to decrease up to day 7 post-reperfusion. Afterward, it continued to rise slightly up to day 14 post-reperfusion. This trend was in parallel with the recovery of the liver damage. MiR-21 expression level in the liver and blood is a predictor of the extent of I/R injury.

Retraction: Linc00472 suppresses breast cancer progression and enhances doxorubicin sensitivity through regulation of miR-141 and programmed cell death 4

Retraction of ‘Linc00472 suppresses breast cancer progression and enhances doxorubicin sensitivity through regulation of miR-141 and programmed cell death 4’ by Pengwei Lu et al., RSC Adv., 2018, 8, 8455–8468, DOI: 10.1039/C8RA00296G

Ssc-miR-21-5p regulates endometrial epithelial cell proliferation, apoptosis and migration via the PDCD4/AKT pathway

ABSTRACTEndometrial receptivity plays a vital role in successful embryo implantation in pigs. MicroRNAs (miRNAs), known as regulators of gene expression, have been implicated in the regulation of embryo implantation. However, the role of miRNAs in endometrial receptivity during the pre-implantation period remains elusive. In this study, we report that the expression level of Sus scrofa (ssc)-miR-21-5p in porcine endometrium tissues was significantly increased from day 9 to day 12 of pregnancy. Knockdown of ssc-miR-21-5p inhibited proliferation and migration of endometrial epithelial cells (EECs), and induced their apoptosis. We verified that programmed cell death 4 (PDCD4) was a target gene of ssc-miR-21-5p. Inhibition of PDCD4 rescued the effect of ssc-miR-21-5p repression on EECs. Our results also revealed that knockdown of ssc-miR-21-5p impeded the phosphorylation of AKT (herein referring to AKT1) by targeting PDCD4, which further upregulated the expression of Bax, and downregulated the levels of Bcl2 and Mmp9. Furthermore, loss of function of Mus musculus (mmu)-miR-21-5p in vivo resulted in a decreased number of implanted mouse embryos. Taken together, knockdown of ssc-miR-21-5p hampers endometrial receptivity by modulating the PDCD4/AKT pathway.