Bisphosphonates induce apoptosis in CLL cells independently of MDR phenotype. Cancer Chemother Pharmacol. 2008;62:165-171. [PMID: 18335218 DOI: 10.1007/s00280-008-0710-1]

Unexpected chronic lymphocytic leukemia B cell activation by bisphosphonates

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, often presenting comorbidities like osteoporosis and requiring, in a relevant proportion of cases, treatment with bisphosphonates (BPs). This class of drugs was shown in preclinical investigations to also possess anticancer properties. We started an in vitro study of the effects of BPs on CLL B cells activated by microenvironment-mimicking stimuli and observed that, depending on drug concentration, hormetic effects were induced on the leukemic cells. Higher doses induced cytotoxicity whereas at lower concentrations, more likely occurring in vivo, the drugs generated a protective effect from spontaneous and chemotherapy-induced apoptosis, and augmented CLL B cell activation/proliferation. This CLL-activation effect promoted by the BPs was associated with markers of poor CLL prognosis and required the presence of bystander stromal cells. Functional experiments suggested that this phenomenon involves the release of soluble factors and is increased by cellular contact between stroma and CLL B cells. Since CLL patients often present comorbidities such as osteoporosis and considering the diverse outcomes in both CLL disease progression and CLL response to treatment among patients, illustrating this phenomenon holds potential significance in driving additional investigations.

Significance of expression of caspase-3 in chronic hepatitis B and C and nonalcoholic steatohepatitis

AIM: To determine the expression of caspase-3 in liver tissues of patients with chronic hepatitis B (CHB), chronic hepatitis C (CHC), or nonalcoholic steatohepatitis (NASH) and to analyze their clinical and pathological significance.

METHODS: Immunohistochemistry was used to determine the expression of caspase-3 in liver tissues from 70 patients with CHB, 50 patients with CHC, 50 patients with NASH, and 15 normal people.

RESULTS: The positive rates of caspase-3 expression in CHB, CHC and NASH were significantly higher than that in normal hepatic tissue (57.1%, 72.0%, 82.0% vs 18.8%; all P < 0.05). Caspase-3 expression was closely related with hepatic cell apoptosis (r = 0.356, P < 0.001). The positive rates of caspase-3 expression increased with the increase in the degree of pathological injury (all P < 0.05).

CONCLUSION: The expression of caspase-3 in CHB, CHC and NASH is closely related with liver cell apoptosis. Overexpression of caspase-3 may play an important role in the development of hepatitis.

Lead acetate induces cell apoptosis and promotes caspase-3 expression in human liver cell line L-02

AIM: To investigate the impact of lead acetate on cell apoptosis and caspase-3 expression in human liver cell line L-02.

METHODS: After L-02 cells were treated with different concentrations (0, 2.5, 40, 100, 200, 400 μmol/L) of lead acetate for 24 or 48 h, the proliferation of L-02 cells was assayed by MTT assay; cell morphological changes were observed after Hoechest33258 staining; and the expression of caspase-3 mRNA and protein was determined by RT-PCR and Western blot.

RESULTS: Compared to the normal control group, the proliferation of L-02 cells was significantly inhibited after treatment with different concentrations of lead acetate for 24 or 48 h (24 h: 0.4678 ± 0.0438, 0.4686 ± 0.0733, 0.4500 ± 0.0712, 0.4244 ± 0.0407, 0.3998 ± 0.0499 vs 0.5234 ± 0.0589; 48 h: 0.4290 ± 0.0607, 0.4184 ± 0.0296, 0.4032 ± 0.0499, 0.3856 ± 0.0386, 0.3750 ± 0.0149 vs 0.5300 ± 0.0397, all P < 0.05 or 0.01). Significant morphological changes were noted in cells treated with lead acetate for 48 h. Compared to the normal control group, the levels of caspase-3 mRNA increased significantly in a dose-dependent manner in L-02 cells treated with lead acetate (1.0912 ± 0.0769, 1.2874 ± 0.144, 1.4536 ± 0.1046, 1.6986 ± 0.1371, 1.9882 ± 0.0925 vs 0.8438 ± 0.0933, all P < 0.01). Additionally, the expression levels of caspase-3 protein also significantly increased after treatment with lead acetate.

CONCLUSION: Lead acetate inhibits proliferation and induces apoptosis of L-02 cells possibly via a mechanism associated with the activation of caspase-3.

Phenylpropanoid glycoside reverse multidrug resistance of colon carcinoma LoVo/Adr cells through induction of apoptosis

AIM: To investigate the relationship between the reversing effect of phenylpropanoid glycoside (PPG) on multidrug resistance of colon carcinoma LoVo/Adr cells and apoptosis.

METHODS: LoVo/Adr cells were divided into three groups: non-treatment (negative control) group, PPG treatment group (treated with 40 mg/L PPG) and verapamil treatment (positive control) group (treated with 5 mg/L VP). The effects of PPG on multidrug resistance of LoVo/Adr cells were examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The effects of PPG on cell apoptosis were detected by flow cytometry. The effects of PPG on the activity of Caspase-3 were evaluated by determining pNA release rate.

RESULTS: PPG could decrease the half maximal inhibitory concentration (IC50) of adriamycin in LoVo cells and reverse their resistance to adriamycin. The reversal index was 9.93. PPG could significantly induce the apoptosis of LoVo cells when compared with the non-treatment group (P < 0.01). The rate of pNA release in the PPG treatment group was significantly higher than that in the non-treatment group (31.75 ± 4.34 pmol/min vs 18.45 ± 2.39 pmol/min, P < 0.01). Caspase-3 inhibitor Z-VAD-FMK could significantly inhibit PPG-induced pNA release (17.69 ± 2.68 pmol/min vs 31.75 ± 4.34 pmol/min, P < 0.01).

CONCLUSION: PPG reverse multidrug resistance of LoVo/Adr cells perhaps through induction of Caspase 3-dependent apoptosis.