OBJECTIVETo 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.

METHODSThe 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.

RESULTSRecombinant 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.

CONCLUSIONRNAi 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.

Cell Proliferation ; Cyclin A2 ; genetics ; Cyclin B2 ; genetics ; Gene Expression ; Gene Expression Regulation, Neoplastic ; Genetic Vectors ; HL-60 Cells ; HMGA2 Protein ; genetics ; Humans ; Lentivirus ; RNA Interference ; RNA, Small Interfering ; genetics

BACKGROUNDHuman epidermal growth factor 2 (HER2) is one of the most important prediction factors, but only 25% - 30% of breast cancer patients HER2 are positive. It is unknown whether there are other molecular markers that could be used to predict prognosis and recurrence in HER2 negative patients. This study investigated correlations of cyclin A2 and HER2 levels with clinical outcomes in 281 patients with invasive breast cancer in order to identify whether cyclin A2 can serve as a prognostic factor in HER2 negative patients.

METHODSImmunohistochemical staining was used to detect cyclin A2 and HER2 expression in 281 patients. Cyclin A2 and HER2 gene amplifications were analyzed using gene analysis and RT-PCR in 12 patients. Risk and survival estimates were analyzed using Log-rank, Kaplan-Meier, and Cox regression analysis; cyclin A2 and HER2 consistency with survival were analyzed using Kappa analysis.

RESULTSPatients with higher cyclin A2 and HER2 expressions had significantly shorter disease-free survival periods (P = 0.047 and P = 0.05, respectively). Kappa analysis performed that cyclin A2 and HER2 showed a low Kappa index (kappa = 0.37), allowing us to conclude that cyclin A2 and HER2 detect different pathologies. Gene analysis and RT-PCR showed that cyclin A2 was upregulated in patients with early relapse; the average increase was 3.69 - 2.74 fold.

CONCLUSIONSCyclin A2 and HER2 are associated with proliferation and high recurrence, particularly when combined. Cyclin A2 is easily detected by nuclear staining and might be a useful biomarker for recurrence risk in HER2 negative patients.

Adult ; Aged ; Aged, 80 and over ; Breast Neoplasms ; genetics ; metabolism ; Cyclin A2 ; genetics ; metabolism ; Female ; Humans ; Immunohistochemistry ; Middle Aged ; Multivariate Analysis ; Receptor, ErbB-2 ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo study the inhibitory effect of small interference RNA (siRNA) targeting cyclin A2 gene on the growth of osteosarcoma MG-63 and human normal skin fibroblast HSF cells and to explore whether cyclin A2 siRNAs could become a useful tool in the treatment of osteosarcoma.

METHODSThree pairs of siRNAs targeting cyclin A2 mRNA and a pair of nonsense siRNA were designed according to the current criteria. SiRNAs were chemically synthesized and purified. The siRNAs were transfected into MG-63 cells and HSF cells via oligofectamine. The cells transfected with nonsense siRNA served as negative control group and those only treated with PBS as blank control group. Quantitative fluorescence RT-PCR, Western-blot, MTT assay, reverse transcriptase (RT)-PCR, flow cytometry and clone forming test were employed to evaluate the efficacy of RNA interference. At the same time, the mRNA expression of PCNA and cyclin B1 in siRNA-treated MG-63 cells were examined.

RESULTSAlthough all three siRNAs could reduce the cyclin A2 expression, siRNA, appeared to be the most effective. After 48 h treatment with siRNA1, cyclin A2 mRNA and protein expression in MG-63 cells was significantly reduced by nearly 80% as compared with that of the blank control group, whereas the negative and blank control groups had similar expression levels. MG-63 cells treated with siRNA1 were arrested at G0/G1 phase by 80.1% and the proliferation of these tumor cells was suppressed 48 h after transfection. Furthermore, MG-63 cells showed a decreased colony forming ability after siRNA1 treatment. In addition, the cyclin A2-depleted MG-63 cells showed decreased levels of PCNA and cyclin B1. In contrast, although cyclin A2 expression in HSF reduced by nearly 60% after treatment by siRNA1 for 48h, these cells exhibited only a slight change in cell cycling, and neither clear inhibition of proliferation nor impaired colony forming ability was observed.

CONCLUSIONCyclin A2 is critical for proliferation of MG-63 cells. Cyclin A2-siRNAs can induce obvious inhibition of cyclin A2 mRNA and protein expression in MG-63 and HSF cells, which consequently down-regulate the proliferation of MG-63 cells. There is little effect on the proliferation of siRNA-treated HSF cells. Those results indicate that siRNAs against cyclin A2 may become a potential antiproliferative tool in future antitumor therapy.

Bone Neoplasms ; metabolism ; pathology ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Cyclin A2 ; genetics ; metabolism ; Cyclin B1 ; metabolism ; Fibroblasts ; cytology ; metabolism ; Gene Knockdown Techniques ; Humans ; Osteosarcoma ; metabolism ; pathology ; Proliferating Cell Nuclear Antigen ; metabolism ; RNA Interference ; RNA, Messenger ; RNA, Small Interfering ; Skin ; cytology ; Transfection