RNA Binding Protein RBM47 Inhibits the K562 Cell Proliferation by Regulating HMGA2 mRNA Expression / 中国实验血液学杂志

OBJECTIVE@#To investigate the regulatory effects of RBM47 on HMGA2 and the function of RBM47 in human chronic myeloid leukemia cell K562.@*METHODS@#K562 cells were transduction by the overexpressed and knockdown RBM47 lentiviral vector. CCK-8 assay was used to detect the effect of RBM47 on the proliferation of K562 cells. Flow cytometry assay was used to detect the effect of RBM47 on the cell cycle progression of K562 cells. RNA immunoprecipitation assay was used to detect the association between RBM47 and HMGA2 mRNA. RT-qPCR was used to detect the effects of RBM47 on the stability of HMGA2 mRNA. Western blot was used to evaluate the effect of RBM47 on HMGA2 protein expression.@*RESULTS@#The overexpressed RBM47 could inhibit the proliferation and cell cycle progression of K562 cells. However, the inhibitation of RBM47 could improve the proliferation and cell cycle progression of K562 cells. RBM47 combined with HMGA2 mRNA could promote the degradation of HMGA2 mRNA. Thus, the overexpressed RBM47 could decrease the expression of HMGA2 protein in K562 cells.@*CONCLUSION@#RNA binding protein RBM47 can inhibit the proliferation of K562 cells by regulating HMGA2 expression.

Circ_0001666 promotes the proliferation and inhibits apoptosis of non-small cell lung cancer cells by targeting the miR-330-5p/HMGA2 axis / 生理学报

Many studies have shown that circular RNAs (circRNAs) play a key regulatory role in the whole biological process of tumors. The purpose of this study was to explore the biological function and molecular mechanism of circ_0001666 in non-small cell lung cancer (NSCLC), so as to provide new targets for the diagnosis and treatment of NSCLC. Gene expression profiles were downloaded from Gene Expression Omnibus (GEO, GSE101586) and the differential genes were obtained by using GEO2R analysis. The quantitative real time polymerase chain reaction (qRT-PCR) was used to detect the expression level of circ_0001666 in NSCLC cells. Cell counting kit-8 (CCK-8) and Annexin V-FITC apoptosis detection kit were respectively used to assess the cell proliferation and apoptosis, where circ_0001666 was knockdown in NSCLC cells. The targeted relationship among mircoRNA 330-5p (miR-330-5p), circ_0001666, and high mobility group A2 protein (HMGA2) was verified by bioinformatics prediction, dual-luciferase reporter gene, RNA immunoprecipitation (RIP) and RNA pull down assay. The results showed that the expression of circ_0001666 in NSCLC cells was significantly up-regulated than that in normal lung epithelial cells. Circ_0001666 knockdown reduced the cell viability and promoted the apoptosis of NSCLC cells, which could be reversed by miR-330-5p inhibitors. MiR-330-5p is the downstream target of circ_0001666 and can be adsorbed by circ_0001666. HMGA2 is a target gene of miR-330-5p, which can be indirectly regulated by circ_0001666. The results suggest that circ_0001666 promotes the proliferation and inhibits apoptosis of NSCLC cells via miR-330-5p/HMGA2 axis.

Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells impacts chemotherapeutics-induced apoptosis / 中南大学学报(医学版)

To investigate the effect of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells on apoptosis induced by chemotherapeutics. 
 Methods: A total of 30 osteosarcoma tissues of sensitive and resistant to chemotherapeutics were divided into a chemotherapy-sensitive group and a chemotherapy-resistant group. The mRNA expression levels of miR-30a and high mobility group protein A2 (HMGA2) in the chemotherapy-sensitive group and the chemotherapy-resistant group, and the mRNA expression levels of miR-30a in osteosarcoma U2-OS cells treated by cisplatin, doxorubicin and methotrexate at different concentrations were detected by real-time PCR. The expression levels of autophagy related protein Beclin 1, microtubule associated protein 1 light chain 3B (LC3B) and autophagy factor P62 were detected by Western blotting. The osteosarcoma U2-OS cells were transfected with miR-30a mimics and miR-30a inhibitors to construct a miR-30a high expression group, a miR-30a low expression group and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after treatment of cisplatin and doxorubicin in these 3 groups were detected by Western blotting; the level of autophagy was detected by monodansylcada (MDC) staining; the level of ROS was detected by dihydroethidium (DHE); the level of cell surviving rate was detected by cell counting kit-8 (CCK-8); the level of apoptosis was detected by annexin APC/PI double staining; the level of mitochondria oxidative damage was detected by mitochondrial membrane potential assay kit with JC-1 (JC-1 method). The interaction between miR-30a and HMGA2 was detected by dual luciferase reporter assay. The osteosarcoma U2-OS cells were transfected with HMGA2 mimics and HMGA2-shRNA to construct a high HMGA2 group, a low HMGA2 group, and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after the treatment of cisplatin were detected by Western blotting.
 Results: The level of miR-30a in the chemotherapy-resistant tissues was significantly lower than that in the chemotherapy-sensitive tissues (P<0.05), and the expression of HMGA2 was opposite comparing to that of miR-30a (P<0.05). After the treatment by low concentration (5 μmol/L) of chemotherapeutics, the level of miR-30a was down-regulated in osteosarcoma U2-OS cells, accompanied with up-regulation of Beclin 1 and LC3B (P<0.01) and down-regulation of P62 (P<0.01). Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly decreased (P<0.05), and the expression level of P62 was significantly increased (P<0.05) in the miR-30a high expression group, which was opposite in the miR-30a low expression group. In the miR-30a high expression group treated by chemotherapeutics, the level of autophagy and the cell survival rate were lower than those in group with low expression of miR-30a, while the levels of ROS, the mitochondrial oxidative damage and the apoptosis were higher than those in group with low expression of miR-30a (all P<0.05). The targeting interaction between HMGA2 and miR-30a were verified by dual luciferase reporter assay. Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly increased (P<0.05), and the expression level of P62 was significantly decreased (P<0.05) in the HMGA2 high expression group, which was opposite in the HMGA2 low expression group.
 Conclusion: Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells is likely to enhance the therapeutic effect of chemotherapeutics.

MiR-219-5p inhibits growth and metastasis of ovarian cancer cells by targeting HMGA2

BACKGROUND: Accumulating studies have demonstrated that high-mobility group A2 (HMGA2), an oncofetal protein, plays a role in tumor development and progression. However, the molecular role of HMGA2 in ovarian carcinoma is yet to be established. MicroRNAs (miRNAs), a group of small noncoding RNAs, negatively regulate gene expression and their dysregulation has been implicated in tumorigenesis. The aim of this study was to investigate the potential involvement of a specific miRNA, miR-219-5p, in HMGA2-induced ovarian cancer. METHODS: The ovarian cancer cell line, SKOV3, was employed, and miR-219-5p and HMGA2 overexpression vectors constructed. The CCK-8 kit was used to determine cell proliferation and the Transwell® assay used to measure cell invasion and migration. RT-PCR and western blot analyses were applied to analyze the expression of miR-219-5p and HMGA2, and the luciferase reporter assay used to examine the interactions between miR-219-5p and HMGA2. Nude mice were employed to characterize in vivo tumor growth regulation. RESULTS: Expression of miR-219-5p led to suppression of proliferation, invasion and migration of the ovarian cancer cell line, SKOV3, by targeting HMGA2. The inhibitory effects of miR-219-5p were reversed upon overexpression of HMGA2. Data from the luciferase reporter assay showed that miR-219-5p downregulates HMGA2 via direct integration with its 3'-UTR. Consistent with in vitro findings, expression of miR-219-5p led to significant inhibition of tumor growth in vivo. CONCLUSION: Our results collectively suggest that miR-219-5p inhibits tumor growth and metastasis by targeting HMGA2.

Effects of HMGA2 on malignant degree, invasion, metastasis, proliferation and cellular morphology of ovarian cancer cells

OBJECTIVE@#To analyze effects of high mobility group AT-hook 2 (HMGA2) on malignant degree, invasion, metastasis, proliferation and cellular morphology of ovarian cancer cells.@*METHODS@#Three methods were applied to observe the effect on HMGA2 expression in ovarian cancer cells and ovarian epithelial cells.@*RESULTS@#After the application of siRNA-HMGA2, number of T29A2-cell clones was decreased, there was significant difference compared with the negative control Block-iT. After application of let-7c, number of T29A2+ cell clones was decreased significantly, however, after the application of Anti-let-7, the number of clones restored, and there was no significant difference compared with the negative control group. After interference, the number of T29A2- cells which passed through Matrigel polycarbonate membrane were significantly lower than the negative control group. After the treatment of siRNA-HMGA2, let-7c and sh-HMGA2 respectively, growth and proliferation of T29A2-, T29A2+ and SKOV3 were slower, and the phenomenon was most obvious in SKOV3. Stable interference of HMGA2 induced mesenchymal-epithelial changes in the morphology of SKOV3-sh-HMGA2.@*CONCLUSIONS@#HMGA2 can promote malignant transformation of ovarian cancer cells, enhance cell invasion and metastasis, and promote cell growth and proliferation of ovarian cancer cells, which can cause ovarian cancer to progress rapidly and affect the quality of life.

Shortening of the 3' untranslated region: an important mechanism leading to overexpression of HMGA2 in serous ovarian cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Oncofetal protein high-mobility-group AT-hook protein 2 (HMGA2) is reactivated in serous ovarian cancer (SOC) and its overexpression correlates with poor prognosis. To explore the mechanism, we investigated whether HMGA2 could avoid microRNA regulation due to gene truncation or 3' UTR shortening by alternative polyadenylation.</p><p><b>METHODS</b>Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate the abundance of different regions of HMGA2 mRNA in 46 SOC samples. Rapid amplification of cDNA 3' ends (3' RACE) and Southern blotting were used to confirm the shortening of 3' untranslated region (UTR). 5' RACE and Southern blotting were used to prove the mRNA decay.</p><p><b>RESULTS</b>No significant difference in the ratio of the stable coding region to the fragile region was observed between SOC and control normal fallopian tubes, indicating that the HMGA2 gene is not truncated in SOC. Varying degrees of 3' UTR shortening in SOC samples were observed by comparing the abundance of the proximal region and distal region of the HMGA2 3' UTR. The ratio of the proximal to the distal region of the 3' UTR correlated significantly with expression of the HMGA2 coding region in SOC (r = 0.579, P < 0.01). Moreover, although the abundance of the HMGA2 coding region varied, all samples, including the very low expressed samples, exhibit relatively high levels of the proximal 3' UTR region, suggesting a dynamic decay of HMGA2 mRNA from the 5' end. The shortening of 3' UTR and the decay from the 5' end were confirmed by 3' RACE, 5' RACE and subsequent Southern blotting.</p><p><b>CONCLUSION</b>Heterogeneous 3' UTR lengths render HMGA2 susceptible to different levels of negative regulation by microRNAs, which represents an important mechanism of HMGA2 reactivation in SOC.</p>

Developmental changes in hematopoietic stem cell properties

Hematopoietic stem cells (HSCs) comprise a rare population of cells that can regenerate and maintain lifelong blood cell production. This functionality is achieved through their ability to undergo many divisions without activating a poised, but latent, capacity for differentiation into multiple blood cell types. Throughout life, HSCs undergo sequential changes in several key properties. These affect mechanisms that regulate the self-renewal, turnover and differentiation of HSCs as well as the properties of the committed progenitors and terminally differentiated cells derived from them. Recent findings point to the Lin28b-let-7 pathway as a master regulator of many of these changes with important implications for the clinical use of HSCs for marrow rescue and gene therapy, as well as furthering our understanding of the different pathogenesis of childhood and adult-onset leukemia.

The effects of lentivirus-mediated RNA interference silencing HMGA2 on proliferation and expressions of cyclin B2 and cyclin A2 in HL-60 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of lentivirus-mediated RNA interference silencing HMGA2 on proliferation and expressions of cyclin B2 and cyclin A2 in HL-60 cell line.</p><p><b>METHODS</b>The protein and mRNA expressions of HMGA2 in HL-60 cells transduced by recombinant lentivirus producing HMGA2 gene short hairpin (shRNA) were examined by Western-blot and reverse transcription-polymerase chain reaction (RT-PCR) analysis; The effects of the lentivirus on cell proliferation inhibiting rate, the ability of cell proliferation and cell cycle were analyzed by soft agar colony formation assay and FCM, respectively; The protein and mRNA expressions of cyclin B2 and cyclin A2 were also examined by Western-blot and RT-PCR.</p><p><b>RESULTS</b>Recombinant lentivirus producing HMGA2 shRNA was successfully constructed, which was identified by PCR and sequencing; Stable HMGA2-deficient HL-60 cell line was established by puromycin, its mRNA and protein expression inhibition rates were (80.66 ± 7.98)% and (76.35 ± 12.72)%, respectively. Silencing of endogenous HMGA2 resulted in efficient inhibition of the cellular proliferative activity, low and flat of the cell growth curve and the lack of typical character of exponential growth. FCM revealed significant more cell cycle G(2)/M arrest \[(30.00 ± 5.78)%\] in HL-60 cell line transfected specific shRNA than control group \[(13.90 ± 4.07)%\] (P < 0.05). The cyclin B2 mRNA and protein expression inhibition rates in stable HMGA2-deficient HL-60 cell line were (67.55 ± 7.69)% and (51.77 ± 4.81)%, respectively, while the expression of cyclin A2 had no significant change compared with control group.</p><p><b>CONCLUSION</b>RNAi silencing of HMGA2 down-regulated cyclinB2, significantly inhibited the proliferation of HL-60 cells and induced the accumulation of HL-60 cells in the G(2)/M phase. Thus, HMGA2 may be an important target for anti-leukemia therapy.</p>

Construction of let-7d expression vector and its inhibitory effect on HMGA2 and ras expression in human ovarian cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To elucidate the role of let-7d in regulating the biological behavior of ovarian cancer cells and their expressions of HMGA2 and ras proteins.</p><p><b>METHODS</b>The pre-let-7d sequence was synthesized and inserted into pcDNA6.2GW/EmGFPmiR and transfected into ovarian cancer IGROV1 cells to cause pre-let-7d overexpression. Real-time quantitative RT-PCR was employed to examine the expression levels of let-7d miRNA and HMGA2 mRNA, and Western blotting was performed to detect the expressions of HMGA2 and ras protein in the transfected cells. The effect of pcDNA6.2GW-let-7d transfection on IGROV1 cell proliferation was determined using MTT assay and the cell apoptosis rate was measured using flow cytometry.</p><p><b>RESULTS</b>The eukaryotic expression vector containing the target gene let-7d was successfully constructed and transfected into IGROV1 cells. The transfected cells showed a marked reduction of HMGA2 expression but a less obvious down-regulation of ras expression. Transfection with pcDNA6.2GW-let-7d to suppress the expression of HMGA2 caused alterations of the phenotype of IGROV1 cells shown by a reduced proliferative activity and increased cell apoptosis.</p><p><b>CONCLUSION</b>Let-7d plays an important role in altering the malignant cell phenotype of ovarian cancer IGROV1 cells by regulating the expression of HMGA2.</p>

Selection and anti-cancer effects of siRNAs targeting HMGA2 gene / 药学学报

High mobility group A2 protein (HMGA2), an architectural factor, is highly expressed in various cancer types including lung cancers. It is a candidate target for cancer therapy. RNAi is an effective gene silencing method with low cost and less time-consuming. It is possible to exploit this technology in therapy. Here, 5 siRNAs targeting Hmga2 gene (HMGA2 siRNA1-5) were designed and synthesized. MTT assay, colony formation assay, transwell assay and flow cytometry were used to evaluate the effects of these siRNAs on lung cancer cell lines (NCI-H446 and A549). Results from cell proliferation, clone formation, migration and apoptosis showed that HMGA2 siRNA1, 3, 5 could affect these aspects for both lung cancer cell lines. Among the five siRNAs, HMGA2 siRNA5 showed the greatest inhibition effects. The inhibition effects of HMGA2 siRNA5 are sequence specific and are not due to the induction of interferon response. Taken together, siRNAs targeting Hmga2 gene are potential candidates for lung cancer gene therapy.

Expression of high mobility group protein A in male mouse testicular cell lines / 中华男科学杂志

<p><b>OBJECTIVE</b>To detect the expression of high mobility group protein A (HMGA) in male mouse testicular cell lines TM4, GC-1spg and GC-2spd(ts), and to pave the theoretical ground for further investigation of the action mechanism of the HMGA gene in male mouse spermatogenesis.</p><p><b>METHODS</b>We detected the expressions of HMGA1 and HMGA2 by RT-PCR and Western blot in the male mouse testicular cell lines TM4, GC-1spg and GC-2spd(ts).</p><p><b>RESULTS</b>HMGA1 and HMGA2 were expressed in the male mouse testicular cell lines TM4, GC-1spg and GC-2spd(ts) at both mRNA and protein levels. Western blot and RT-PCR methods showed similar results.</p><p><b>CONCLUSION</b>The expression of HMGA may be involved in the cell division and proliferation of TM4, GC-1spg and GC-2spd(ts) and play an important role in spermatogenesis of male mice.</p>