[Effect of Inhibiting SIX1 Expression on Drug-resistance of Acute Myeloid Leukemia Cell Line HL-60/ADR Cells].

OBJECTIVE: To establish HL-60 cells and adriamycin resistant HL-60 cells (H-60/ADR) in which the expression of homologous box gene 1 (SIX1) was inhibited, and investigate the effect of inhibiting the expression of SIX1 on the drug resistance. METHODS: Lentivirus was used to transfect HL-60 and HL-60/ADR cells, and the cell lines stably inhibiting the expression of SIX1 were screened by puromycin. CCK-8 assay was used to detect the proliferation ability of cells in each group, apoptosis kit was used to detect the cell apoptosis, and real-time quantitative PCR was used to detect the expression level of drug-resistant related genes. RESULTS: HL-60 and HL-60/ADR stably transfected cell lines with down-regulation of SIX1 expression were successfully constructed. Compared with control group, the inhibition of SIX1 expression significantly inhibited the proliferation of HL-60 and HL-60/ADR cells (P <0.05), increased the apoptosis rate (P <0.05), and the sensitivity of cells to adriamycin increased after inhibition of SIX1 expression. CONCLUSION: Inhibition of SIX1 expression can improve cell sensitivity to adriamycin, and its role in reversing drug resistance may be related to the promotion of apoptosis gene expression.

Down-regulation of the Smad signaling by circZBTB46 via the Smad2-PDLIM5 axis to inhibit type I collagen expression.

BACKGROUND: Abnormal type I collagen (COL1) expression is associated with the development of many cardiovascular diseases. The TGF-beta/Smad signaling pathway and circRNAs have been shown to regulate COL1 gene expression, but the underlying molecular mechanisms are still not fully understood. METHODS: Gain- and loss-of-function experiments were prformed to study the effect of circZBTB46 on the expression of alpha 2 chain of type I collagen (COL1A2). Co-immunoprecipitation assay was performed to observe the interaction between two proteins. RNA immunoprecipitation assay and biotin pull-down assay were performed to observe the interaction of circZBTB46 with PDLIM5. RESULTS: In this study, we investigated the role of circZBTB46 in regulating COL1A2 expression in human vascular smooth muscle cells (VSMCs). We found that circZBTB46 is expressed in VSMCs and that TGF-beta inhibits circZBTB46 formation by downregulating KLF4 expression through activation of the Smad signaling pathway. CircZBTB46 inhibits the expression of COL1A2 induced by TGF-beta. Mechanistically, circZBTB46 mediates the interaction between Smad2 and PDLIM5, resulting in the inhibition of Smad signaling and the subsequent downregulation of COL1A2 expression. Furthermore, we found that the expression of TGF-beta and COL1A2 is decreased, while circZBTB46 expression is increased in human abdominal aortic aneurysm tissues, indicating that circZBTB46-mediated regulation of TGF-beta/Smad signaling and COL1A2 synthesis in VSMCs plays a crucial role in vascular homeostasis and aneurysm development. CONCLUSIONS: CircZBTB46 was identified as a novel inhibitor of COL1 synthesis in VSMCs, highlighting the importance of circZBTB46 and PDLIM5 in regulating TGF-beta/Smad signaling and COL1A2 expression.

Morin Inhibits Dox-Induced Vascular Inflammation By Regulating PTEN/AKT/NF-κB Pathway.

The side effects of doxorubicin (Dox) may influence the long-term survival of patients with malignancies. Therefore, it is necessary to clarify the mechanisms generating these side effects induced by Dox and identify effective therapeutic strategies. Here, we found that interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and tumor necrosis factor-alpha (TNF-α) levels were significantly increased in vascular tissues of Dox-treated mice and Dox-treated vascular smooth muscle cells (VSMCs). Furthermore, we revealed that Dox downregulated the phosphatase and tension homology deleted on chromosome 10 (PTEN) level while upregulated p-AKT and p65 level in VSMCs in vitro. Overexpression of PTEN in VSMCs partly reversed Dox-induced inflammation. Importantly, we demonstrated that Morin could inhibit Dox-induced inflammation by facilitating an increase of PTEN, thus inhibiting the activation of protein kinase B (AKT)/nuclear factor kappa B (NF-κB)/pathway. Additionally, we showed that Morin could reduce the miR-188-5p level, which was increased in Dox-treated VSMCs. Inhibition of miR-188-5p suppressed Dox-induced vascular inflammation in vitro. In conclusion, Morin reduced the Dox-induced vascular inflammatory by moderating the miR-188-5p/PTEN/AKT/NF-κB pathway, indicating that Morin might be a therapeutic agent for overcoming the Dox-induced vascular inflammation.

[The Effect of si-PKM2 on Proliferation and Apoptosis of Acute Leukemic Cells and Its Molecular Mechanism].

OBJECTIVE: To investigate the effect of glycolytic enzyme pyruvate kinase type 2 (PKM2) on the proliferation and apoptosis of human leukemia HL-60 cells. METHODS: si-PKM2 plasmid was transfected into HL-60 cells (set as si-PKM2 group), and blank vector transfected cells were set as control group (si-Ctl group). The expression levels of PKM2 mRNA and protein in si-Ctl group and si-PKM2 group were detected by RT-qPCR and Western blot. CCK-8 cell detection kit was used to detect the proliferation ability of the cells in the two groups. Flow cytometry was used to detect the changes of cell cycle and apoptosis. Western blot and RT-qPCR were used to detect the changes of p-Akt and p-mTOR protein levels in PI3K/Akt/mTOR signaling pathway and the changes of glycolysis-related mRNA levels of the cells in the two groups. The changes in glucose consumption and lactic acid production of the cells were assayed. Over expressed PKM2, HL-60 cells were treated with PI3K inhibitor LY294002 or galactose, the changes in cell proliferation ability, cell cycle and apoptosis, as well as changes in glucose consumption and lactic acid production were detected. RESULTS: Interfered by si-PKM2, mRNA and protein levels of PKM2 in si-PKM2 group significantly decreased, and proliferation ability of the cells was also reduced (P<0.05). After PKM2 knockdown, the cells were significantly blocked at G1 phase, and cell apoptosis was obviously induced (P<0.05). p-Akt and p-mTOR levels were lower in si-PKM2 group than those in si-Ctl group. The glucose consumption and lactic acid production significantly decreased in si-PKM2 cells. Overexpressed PKM2, HL-60 cells were treated with PI3K inhibitor LY294002. The glucose consumption and lactate acid production induced by overexpressed PKM2 were reduced. Overexpressed PKM2, HL-60 cells showed no significant changes in cell proliferation, cycle and apoptosis when cultured with galactose. CONCLUSION: PKM2 knockdown can inhibit the proliferation and induce apoptosis of HL-60 cells, and its molecular mechanism may be related to the PKM2-mediated PI3K/Akt/mTOR-glycolysis, which suggesting that PKM2 may serve as a molecular target for the prevention and treatment of leukemia.

circACTA2 mediates Ang II-induced VSMC senescence by modulation of the interaction of ILF3 with CDK4 mRNA.

Chronic angiotensin II (Ang II) stimulation induces vascular smooth muscle cell (VSMC) senescence, and circRNAs and members of the ILF3 family are implicated in cellular senescence, but the mechanism underlying regulation of circRNAs and ILF3 by Ang II in VSMCs remains poorly understood. Here, a model of Ang II-induced VSMC senescence and the renal artery of hypertensive patients were used to investigate the roles and mechanisms of circACTA2 and ILF3 in VSMC senescence. We show that circACTA2 expression was elevated in Ang II-stimulated VSMCs and in the vascular walls of hypertensive patients. circACTA2 knockdown largely abrogated Ang II-induced VSMC senescence as shown by decreased p21 expression and increased CDK4 expression as well as by decreased SA ß-gal-positive cells. Oligo pull-down and RIP assays revealed that both circACTA2 and CDK4 mRNA could bind with ILF3, and Ang II facilitated circACTA2 association with ILF3 and attenuated ILF3 interaction with CDK4 mRNA. Mechanistically, increased circACTA2 by Ang II reduced ILF3 association with CDK4 mRNA by competing with CDK4 mRNA to bind to ILF3, which decreases CDK4 mRNA stability and protein expression, thus leading to Ang II-induced VSMC senescence. Targeting the circACTA2-ILF3-CDK4 axis may provide a novel therapeutic strategy for VSMC senescence-associated cardiovascular diseases.

Tanshinone IIA regulates human AML cell proliferation, cell cycle, and apoptosis through miR-497-5p/AKT3 axis.

BACKGROUND: The roots of Salvia miltiorrhiza are used in traditional Chinese medicine (TCM) and have high medicinal value. Tanshinone IIA (Tan IIA) is the active ingredient of Salvia miltiorrhiza which can inhibit the growth of acute leukemia cell lines in vitro, although the mechanism remains unclear. METHODS: CCK-8 assays and BrdU stain were used to evaluate cell proliferation ability. Western blot analysis was used to detect protein expression. miR-497-5p expression level was detected by using qRT-PCR, and Annexin V-FITC/propidium iodide (PI) was used to detect cell apoptosis. RESULTS: Here we reported that Tan IIA could inhibit cell proliferation, induce cell cycle arrest, and promote cell apoptosis in acute myeloid leukemia (AML) cells. Thus, Tan IIA had the anti-cancer activity in AML cell lines, which was likely mediated by up-regulation of miR-497-5p expression. Our data further showed that in AML cells, the same effects were observed with overexpression of miR-497-5p by a miR-497-5p mimic. We demonstrated that Tan IIA could inhibit the expression of AKT3 by up-regulating the expression of miR-497-5p. We subsequently identified that AKT3 was the direct target of miR-497-5p, and that treatment with Tan IIA obviously reversed the effect of treatment with an miR-497-5p inhibitor under harsh conditions. In turn, PCNA expression was increased and cleaved Caspase-3 was suppressed, which contributed to the growth of AML cells. CONCLUSIONS: Our results showed that Tan IIA could inhibit cell proliferation in AML cells through miR-497-5p-mediated AKT3 downregulation pathway.

Tanshinone â ¡A inhibits VSMC inflammation and proliferation in vivo and in vitro by downregulating miR-712-5p expression.

The inflammation and proliferation of vascular smooth muscle cells (VSMCs) are the basic pathological feature of proliferative vascular diseases. Tanshinone ⅡA (Tan ⅡA), which is the most abundant fat-soluble element extracted from Salvia miltiorrhiza, has potent protective effects on the cardiovascular system. However, the underlying mechanism is still not fully understood. Here, we show that Tan ⅡA significantly inhibits neointimal formation and decreases VSMC inflammation by upregulating the expression of KLF4 and inhibiting the activation of NFκB signaling. Using a microRNA array analysis, we found that miR-712-5p expression is significantly upregulated in tumor necrosis factor alpha (TNF-α)-treated VSMCs. Loss- and gain-of-function experiments revealed that transfection of miR-712-5p mimic promotes, whereas depletion of miR-712-5p suppresses TNF-α-induced VSMC inflammation, leading to amelioration of intimal hyperplasia induced by carotid artery ligation. Moreover, depletion of miR-712-5p by its antagomir largely abrogates TNF-α-induced VSMC proliferation. Our findings suggest that miR-712-5p mediates the stimulatory effect of TNF-α on VSMC inflammation, and that Tan ⅡA inhibits VSMC inflammation and proliferation in vivo and in vitro by suppression of miR-712-5p expression. Targeting miR-712-5p may be a novel therapeutic strategy to prevent proliferative vascular diseases.

De-regulated STAT5A/miR-202-5p/USP15/Caspase-6 regulatory axis suppresses CML cell apoptosis and contributes to Imatinib resistance.

BACKGROUND: STAT5 plays an important role in the transformation of hematopoietic cells by BCR-ABL. However, the downstream target genes activated by STAT5 in chronic myeloid leukemia (CML) cells remain largely unclear. Here, we investigated the mechanistic functional relationship between STAT5A-regulated microRNA and CML cell apoptosis. METHODS: The expression of USP15, Caspase-6, STAT5A-regulated miR-202-5p and STAT5A was detected by qRT-PCR and Western blotting in CML cell lines and PBMCs of CML patients. Cell apoptosis was evaluated by flow cytometry. Both gain- and loss-of-function experiments were used to investigate the roles of USP15, miR-202-5p and STAT5A in CML. Luciferase reporter assay detected the effect of miR-202-5p on USP15 expression. Xenograft animal model was used to test the effect of anti-miR-202-5p and pimozide on K562 cell xenograft growth. RESULTS: USP15 expression was significantly downregulated in CML cell lines and PBMCs of CML patients. Depletion of USP15 increased, whereas overexpression of USP15 reduced the resistance of CML cells to Imatinib. Further, decreased deubiquitinating activity of USP15 by USP15 downregulation led to reduced caspase-6 level, thus attenuating CML cell apoptosis. Mechanistically, miR-202-5p was upregulated in K562G cells and negatively regulated USP15 expression by directly targeting USP15 3'-UTR. Correspondingly, upregulation of miR-202-5p enhanced the resistance of CML cells to Imatinib by inhibiting cell apoptosis. Importantly, STAT5A was upregulated in CML cells and directly activated miR-202-5p transcription by binding to the pre-miR-202 promoter. Pimozide induced CML cell apoptosis and significantly reduced K562 cell xenograft growth in vivo by blocking STAT5A/miR-202-5p/USP15/Caspase-6 regulatory axis. CONCLUSIONS: we provide the first evidence that de-regulated STAT5A/miR-202-5p/USP15/Caspase-6 regulatory axis suppresses the apoptosis of CML cells, targeting this pathway might be a promising therapeutic approach for the treatment of CML.

Upregulation of ERp57 promotes clear cell renal cell carcinoma progression by initiating a STAT3/ILF3 feedback loop.

BACKGROUND: ERp57 dysfunction has been shown to contribute to tumorigenesis in multiple malignances. However, the role of ERp57 in clear cell renal carcinoma (ccRCC) remains unclear. METHODS: Cell proliferation ability was measured by MTT and colony forming assays. Western blotting and quantitative real-time PCR (qRT-PCR) were performed to measure protein and mRNA expression. Co-immunoprecipitation (CoIP) and proximity ligation assay (PLA) were performed to detect protein-protein interaction. Chromatin immunoprecipitation (ChIP), ribonucleoprotein immunoprecipitation (RIP), and oligo pull-down were used to confirm DNA-protein and RNA-protein interactions. Promoter luciferase analysis was used to detect transcription factor activity. RESULTS: Here we found ERp57 was overexpressed in ccRCC tissues, and the higher levels of ERp57 were correlated with poor survival in patients with ccRCC. In vivo and in vitro experiments showed that ccRCC cell proliferation was enhanced by ERp57 overexpression and inhibited by ERp57 deletion. Importantly, we found ERp57 positively regulated ILF3 expression in ccRCC cells. Mechanically, ERp57 was shown to bind to STAT3 protein and enhance the STAT3-mediated transcriptional activity of ILF3. Furthermore, ILF3 levels were increased in ccRCC tissues and associated with poor prognosis. Interestingly, we revealed that ILF3 could bind to ERp57 and positively regulate its expression by enhancing its mRNA stability. Furthermore, ccRCC cell proliferation was moderated via the ERp57/STAT3/ILF3 feedback loop. CONCLUSIONS: In summary, our results indicate that the ERp57/STAT3/ILF3 feedback loop plays a key role in the oncogenesis of ccRCC and provides a potential therapeutic target for ccRCC treatment.

Morin Inhibits Proliferation and Induces Apoptosis by Modulating the miR-188-5p/PTEN/AKT Regulatory Pathway in CML Cells.

Increased activity of the PI3K/AKT/mTOR pathway has been observed in chronic myeloid leukemia (CML). Morin, a kind of flavonoid, exhibits a significant anticancer activity by suppressing the PI3K/AKT signaling pathway. However, the effect of morin on CML and its underlying mechanisms is poorly understood. Here, we found that morin dose dependently inhibited the proliferation of CML cell lines K562 and KCL22 and induced their apoptosis, with a significant increase in cell apoptosis upon exposure of cells to 50 µmol/L morin. Moreover, morin significantly reduced CML xenograft growth in nude mice. Mechanically, morin attenuated phosphorylated AKT level by upregulating PTEN expression, thus leading to the inhibition of AKT signaling. Knockdown of PTEN by its siRNA completely abrogated morin-induced cell apoptosis, indicating that PTEN mediates the inductive effect of morin on CML cell apoptosis. More importantly, we found that miR-188-5p was significantly upregulated in CML patients and CML cell lines. Treating CML cells with morin markedly downregulated the miR-188-5p expression level. Further, we demonstrated that miR-188-5p repressed PTEN expression by directly targeting its 3'-UTR. miR-188-5p downregulation induced by morin enhanced CML cell apoptosis by relieving miR-188-5p repression of PTEN expression. In summary, morin exerts significant anticancer efficacy in CML by regulating the miR-188-5p/PTEN axis and thus repressing the PI3K/AKT signaling.

miR-140-5p induces cell apoptosis and decreases Warburg effect in chronic myeloid leukemia by targeting SIX1.

microRNAs (miRNA), as tumor suppressors or oncogenes, are involved in modulating cancer cell behavior, including cell proliferation and apoptosis. The miR-140-5p acts as a tumor suppressor in several tumors, but the role of miR-140-5p in chronic myeloid leukemia (CML) remains unclear. Here, we investigated the suppression of miR-140-5p in CML patients and CML cell lines using quantitative PCR (qPCR) and fluorescence in situ hybridization (FISH). Overexpression miR-140-5p in CML cells significantly inhibited cell proliferation as revealed by the CCK-8 assay and promoted cell apoptosis as revealed by flow cytometry. Moreover, the sine oculis homeobox 1 (SIX1) gene had been confirmed as a direct target of miR-140-5p using bioinformatics analysis and luciferase reporter assays. Overexpression of miR-140-5p decreased the SIX1 protein level in CML cells. SIX1 mRNA and protein levels were significantly up-regulated in CML patients and CML cell lines. Knockdown of SIX1 expression significantly inhibited CML cell proliferation and promoted cell apoptosis. Furthermore, SIX1 as a transcriptional factor positively regulated pyruvate kinase isozyme type M2 (PKM2) expression and played an important role in the Warburg effect. In addition, these findings indicated that miR-140-5p functions as a tumor suppressor and plays a critical role in CML cell apoptosis and metabolism by targeting SIX1. Moreover, the miR-140-5p/SIX1 axis may be a potential therapeutic target in CML.

Microvesicles shed from bortezomib-treated or lenalidomide-treated human myeloma cells inhibit angiogenesis in vitro.

Angiogenesis plays a significant role in the pathogenesis of multiple myeloma (MM). Microvesicles (MVs), a type of extracellular vesicles, are known as important players in cell-to-cell communication. MM-derived MVs have exhibited the activity of promoting angiogenesis. Bortezomib and lenalidomide are important drugs for treating myeloma. Therefore, the aim of the present study was to investigate whether and how MVs secreted from human myeloma cells exposed to bortezomib and lenalidomide affect angiogenesis. RPMI-8226 human myeloma cells and human umbilical vein endothelial cells (HUVECs) were used. MVs were isolated from the drug-treated RPMI-8226 cells. The number of the MVs were analyzed with flow cytometry. The expression of pro-angiogenic factors was analyzed with PCR and ELISA. The angiogenic potential of HUVECs was examined. NF-κB activation was analyzed using PCR, immunofluorescent staining and western blotting assays. We showed that bortezomib treatment induced an increase in the number of MVs shed from myeloma cells, but the number of MVs was not significantly altered by lenalidomide. The expression levels of vascular endothelial growth factor (VEGF), interleukin 6 (IL-6) and basic fibroblast growth factor (bFGF) were reduced in the MVs from the RPMI-8226 cells exposed to bortezomib and lenalidomide. Consequently, these MVs exhibited reduced angiogenic potential, as evaluated by wound healing tests, Boyden chamber assays and tube formation assays. Co-culturing HUVECs with drug-treated MVs inhibited NF-κB activation in the HUVECs and reduced the secretion of pro-angiogenic factors. In conclusion, bortezomib and lenalidomide treatment of cultured myeloma cells can block MV-induced angiogenesis and hence provides another mechanism for anti-angiogenic therapy.

[Effect of Rapamycin on Expression of Survivin and Caspase-3 and Its Influence on K562 Cell Ultrastructure].

OBJECTIVE: To investigate the effect of rapamycin on the expression of survivin and caspase-3 at mRNA level in K562 cells and the influence of rapamycin on K562 cell ultrastructure. METHODS: The effects of rapamycin at various concentration on K562 cell proliferation were analyzed by CCK8; the morphological characteristics of K562 cells was observed by transmission electron microscopy; the expression of survivin and caspase-3 at mRNA level in K562 cells treated with rapamycin was detected by RT-PCR. RESULTS: The proliferation of K562 cells was significantly inhibited by rapamycin. The apoptosis level of K562 cells increased with increase of rapamycin concentration, the expression of survivin at mRNA level decreased with increase of rapamycin concentration (P < 0.05). The expression of caspase-3 at mRNA level increased with increase of rapamycin concentration. CONCLUSION: Rapamycin can prornote K562 cell apoptosis through up-regulating caspase-3 level and reduceing survivin level.