Effect of lanthanum chloride on the proliferation and expressions of cyclin D1 and cyclin dependent kinase 4 in rat hepatocellular carcinoma CBRH-7919 cells

Liming YANG; Wenhua JIANG; Liming HAO; Xiaoting MENG

ABSTRACT

BACKGROUND:

It has been proved that the rare earth compounds can obviously restrain the growth of tumor in vitro and in vivo.

OBJECTIVE:

To check the effect of chlorinated lanthanum (LaCl3) on the expressions of cyclin D1 and cyclin dependent kinase 4 (CDK4) of hepatocellular carcinoma cells.

DESIGN:

Controlled observation.

SETTING:

Department of Nephropathy, First Clinical Hospital, Jilin University. MATERIALS The experiment was carried out in the cell culture laboratory (province-level) of Department of Histology and Embryology, Jilin University from July 2002 to June 2003. Wells of the microwell plate seeded with CBRH-7919 cells were randomly divided into 4 groups according to the dose of LaCl3 control, 0.01, 0.1, 1.0 mmol/L LaCl3. And each group was further divided into three subgroups according to the culture time 1, 3, 5 days, with 6 wells for each.

METHODS:

The growth of CBRH-7919 cells was monitored following treated with 0.01, 0.1, 1.0 mmol/L LaCl3 for 1, 3, 5 days in vitro, respectively. ① Absorbance(A) of each well was measured by MTT assay.② The changes of distribution of cells into different phases of cell cycle were detected by flow cytometry. ③ Cyclin D1 and CDK4 expression was detected by immunocytochemical analysis.MAIN OUTCOME

MEASURES:

The expression of cyclin D1 and CDK4 in CBRH-7919 cells of different doses of LaCl3 at different time.

RESULTS:

Effect of LaCl3 on the growth of CBRH-7919 On days 3 and 5, the A value of each well in the 0.1 and 1.0 mmol/L LaCl3 groups was respectively significantly lower than that in the control group (day 3 1.140±0070, 0.706±0.092,1.461±0.087; day 5 1.888±0.020,0.625±0.037,2.544±0.032, respectively) (P ＜ 0.05,0.001 ). ②Effect of LaCl3 on the percentage of CBRH-7919 cells at G0/G1 stage On days 1, 3, and 5, the percentage of CBRH-7919 cells at G0/G1 stage in the 1.0 mol/L LaCl3 group was respectively significantly higher than that in the blank control group [(60.70±0.20)%, (39.49±0.67)%; (61.66±0.97)%, (45.56±1.00)%; (69.92±0.18)%, (49.24±0.27)%, (P ＜ 0.01,0.001 )]; On day 5, the percentage of CBRH-7919 cells at G0/G1 stage in the 0.1 mol/L LaCl3 group was respectively significantly higher than that in the blank control group[(58.88±0.73)%, (49.24±0.27)%, P ＜ 0.05]. ③ Effect of LaCl3 on the expressions of cyclin D1 and CDK4 of CBRH-7919 cells On day 1, the expressions of cyclin D1 and CDK4 of CBRH-7919 cells in the 0.1 and 1.0 mmol/L LaCl3 groups were respectively lower than those in the blank control group (expression of cyclin D1 562±35,453±22,860±82;expression of CDK4 705±84,680±28,762±16, P ＜ 0.05, 0.01 and 0.001).

CONCLUSION:

LaCl3 inhibited the growth of CBRH-7919 cells correlating down-regulating cyclin D1 and CDK4 as reflected on the cell cycle arrest of CBRH-7919 cells from G1 stage to S stage.