[Effect of Down-Regulation of ANRIL on Proliferation and Apoptosis of Kasumi-1 Cells and Its Potential Mechanism].

OBJECTIVE: To investigate the down-regulation of ANRIL (Antisense non-coding RNA in the INK4 Locus) effects on proliferation and apoptosis of Kasumi-1 cells and its related molecular mechanism. METHODS: Recombinant lentivirus was used to construct ANRIL down-regulation Kasumi-1 cells (sh-ANRIL group) and its control cells (sh-NC group). A fluorescence microscope was used to observe the transfection efficiency, RT-qPCR was used to detect knockdown efficiency and ANRIL expression in PBMCs and MBMCs of patients with acute myeloid leukemia (AML). Proliferation and apoptosis of Kasumi-1 cells were assayed by CCK-8 method and flow cytometry. Western blot was employed to detect the expression of PI3K, AKT, p-AKT, and relevant protein after down-regulation of ANRIL in Kasumi-1 cells. RESULTS: ANRIL overexpressed significantly in PBMCs and MBMCs of patients with AML, the transfection efficiency of recombinant lentivirus carrying sh-ANRIL and sh-NC on Kasumi-1 cells exceeded 90%, and the knockdown efficiency was 70%. When DNR was administrated for 24, 48, and 72 hours, the cell inhibition rate of the sh-ANRIL group was (47.40±1.49)%, (69.11±0.51)% and (91.82±1.10)%, which were significantly higher than those of the sh-NC group, respectively (P<0.05). The apoptotic rate in the sh-ANRIL group was (10.29±0.58)%, which was significantly higher than (5.42±0.67)% of the sh-NC group (P<0.01). After DNR treatment for 24 hours, the apoptotic rate of the sh-ANRIL group was (54.41±1.69)%, which was significantly higher than (38.28±1.42)% of sh-NC group (P<0.001). Western blot revealed that the protein levels of PI3K, p-AKT, PCNA, and BCL-2 in the sh-ANRIL group were reduced significantly than those in the sh-NC group, while the BAX protein expression increased. CONCLUSION: ANRIL may affect the proliferation and apoptosis of Kasumi-1 cells through PI3K/AKT signaling pathway. ANRIL is a potential therapeutic target for AML.

SNHG16 lncRNAs are overexpressed and may be oncogenic in human gastric cancer by regulating cell cycle progression.

The small nucleolar RNA host gene 16 (SNHG16) has recently been shown to be a putative oncogene in gastric cancer (GC) and other cancer types, but how its four lncRNA variants are expressed in any physiological and pathological situation remains unknown. To investigate the expression and function of the four lncRNA variants of SNHG16, mainly the variant 1, in GC, we performed quantitative PCR to determine the RNA levels of the four variants in 60 GC tissue samples and several cell lines. We also studied how knocking down of SNHG16 with siRNA affected proliferation, apoptosis, cell cycle progression, as well as migration and invasion of GC cells. Our results showed that variants 1 and 4 were overexpressed in GC tissues compared with adjacent uninvolved tissues. Knockdown of the four variants, mainly the variant 1, enhanced apoptosis and inhibited cell cycle progression of a GC cell line by arresting the cells at the G1 phase. These cellular effects were associated not only with decreased protein levels of c-Myc, PCNA, cyclins D1, E1, A2 and B, as well as CDKs 2 and 6, but also with increased protein levels of the p21, p27 and p53. Knockdown of total SNHG16 lncRNAs also inhibited invasion and migration of the GC cells in vitro. These results collectively suggest that SNHG16 may be oncogenic in GC by regulating cell cycle progression and may serve as a GC biomarker.

[K562 cell line resistance to nilotinib induced in vitro and preliminary investigation of its mechanisms].

OBJECTIVE: To establish a bcr-abl(+) cell line resistance to nilotinib, and to investigate the possible mechanisms of resistance. METHODS: K562 cells were treated with gradually increasing concentrations of nilotinib to generate resistance cell line K562-RN. The folder of drug-resistance was evaluated by MTT assay. Cells apoptosis rate was detected by flow cytometry, the mRNA level of bcr-abl fusion gene by FISH, and the expression of apoptosis relative gene mRNA and protein (such as bcr-abl, HO-1, mdr1, Bcl-2 and caspase-3) by RQ-PCR and western blot. RESULTS: The resistant cell line K562-RN was successfully established, with 2.01 fold resistant to nilotinib compared with K562 cell line \[the IC(50) value of nilotinib to K562 and K562-RN were (12.320 ± 1.720) µmol/L and (24.742 ± 2.310) µmol/L, respectively\]. It also had the cross resistance to adriamycin, homoharringtonine, etoposide and imatinib. Treated with different concentrations of nilotinib, cell apoptosis rate of K562-RN was significantly lower than that of K562 cells. The rate of bcr-abl gene positive cells was 92% in K562-RN by FISH assay. The mRNA and protein levels of bcr-abl, HO-1 and mdr1 expression up-regulated in K562-RN cells, while those of caspase-3 expression down-regulated, being significantly statistical difference when compared with K562 cells (P < 0.05). CONCLUSION: Human leukemic cell line resistance to nilotinib, K562-RN is established successfully by gradually increasing concentrations of drug. The mechanisms of resistance in K562-RN is probably associated with increasing expression of bcr-abl, HO-1, mdr1 and decreasing expression of caspase-3 mRNA and protein levels.