Chronic lymphocytic leukemia: advances in biology and therapeutics

Nardostachys chinensis induces granulocytic differentiation with the suppression of cell growth through p27(Kip1) protein-related G0/G1 phase arrest in human promyelocytic leukemic cells

CONTEXT

Nardostachys chinensis Batalin (Valerianaceae) has been used in Korean traditional medicine to elicit stomachic and sedative effects. However, the anti-leukemic activities of N. chinensis have not been well examined.

OBJECTIVE

To investigate the effect of N. chinensis on differentiation and proliferation in the human promyelocytic leukemic HL-60 cells.

MATERIALS AND METHODS

The dried roots and stems of N. chiensis are extracted using hot water and then freeze-dried. The yield of extract was 12.82% (w/w). The HL-60 cells were treated with 25-200 μg/ml of N. chinensis for 72 h or 100 μg/ml of N. chinensis for 24-72 h.

RESULTS

Nardostachys chinensis significantly inhibited cell viability dose dependently with an IC50 of 100 μg/ml in HL-60 cells. Nardostachys chinensis induced differentiation of the cells as measured by reduction activity of NBT and expression of CD11b but not of CD14 as analyzed by flow cytometry, which indicates a differentiation toward the granulocytic lineage. Nardostachys chinensis also induced growth inhibition through G0/G1 phase arrest in the cell cycle of HL-60 cells. Among the G0/G1 phase in the cell cycle-related protein, the expression of cyclin-dependent kinase (CDK) inhibitor p27(Kip1) was increased in N. chinensis-treated HL-60 cells, whereas the expression levels of CDK2, CDK4, CDK6, cyclin D1, cyclin D3, cyclin E, and cyclin A were decreased. Interestingly, N. chinensis markedly enhanced the binding of p27(Kip1) with CDK2 and CDK6.

DISCUSSION AND CONCLUSION

This study demonstrated that N. chinensis is capable of inducing cellular differentiation and growth inhibition through p27(Kip1) protein-related G0/G1 phase arrest in HL-60 cells.

Differentiation-Promoting Activity of Pomegranate (Punica granatum) Fruit Extracts in HL-60 Human Promyelocytic Leukemia Cells

Differentiation refers to the ability of cancer cells to revert to their normal counterparts, and its induction represents an important noncytotoxic therapy for leukemia, and also breast, prostate, and other solid malignancies. Flavonoids are a group of differentiation-inducing chemicals with a potentially lower toxicology profile than retinoids. Flavonoid-rich polyphenol fractions from the pomegranate (Punica granatum) fruit exert anti-proliferative, anti-invasive, anti-eicosanoid, and pro-apoptotic actions in breast and prostate cancer cells and anti-angiogenic activities in vitro and in vivo. Here we tested flavonoid-rich fractions from fresh (J) and fermented (W) pomegranate juice and from an aqueous extraction of pomegranate pericarps (P) as potential differentiation-promoting agents of human HL-60 promyelocytic leukemia cells. Four assays were used to assess differentiation: nitro blue tetrazolium reducing activity, nonspecific esterase activity, specific esterase activity, and phagocytic activity. In addition, the effect of these extracts on HL-60 proliferation was evaluated. Extracts W and P were strong promoters of differentiation in all settings, with extract J showing only a relatively mild differentiation-promoting effect. The extracts had proportional inhibitory effects on HL-60 cell proliferation. The results highlight an important, previously unknown, mechanism of the cancer preventive and suppressive potential of pomegranate fermented juice and pericarp extracts.

Fludarabine plus cyclophosphamide for the treatment of advanced chronic lymphocytic leukemia

OBJECTIVES

Therapeutic results in advanced chronic lymphocytic leukemia (CLL) are still unsatisfactory in terms of complete remission achievement and duration, in spite of the extensive use of purine analogs. The objective of this study was to describe the clinical characteristics and treatment results from a series of 32 patients managed with a therapeutic program based on the combination of fludarabine and cyclophosphamide (CTX).

METHODS

Thirty-two patients (median age 63 yr, range 42-75 yr) with newly diagnosed (47%) or refractory-relapsed (53%) CLL were programmed to receive six courses of a 3-d combination of fludarabine at 30 mg/m2/d plus CTX at 300 mg/m2/d. Refractory-relapsed patients had previously received different chemotherapy lines from 1 to 5.

RESULTS

Fourteen of 32 (44%) patients achieved a complete remission, 16 (50%) obtained partial remission and two (6%) failed to respond. The CR rate was higher in untreated patients; in particular, CR was achieved in nine of 15 (60%) newly diagnosed cases as opposed to five of 17 (29%) among pretreated patients. Toxicity was caused by myelosuppression and/or infections in most cases. After a median follow-up of 24 months (range 8-48 months), 20 of 32 patients (62%) are alive, and 14 of 32 (44%) are free from progression. Median overall survival and median time to progression were 35 and 25 months, respectively.

CONCLUSION

The combination of fludarabine with CTX is effective in advanced CLL with acceptable toxicity, either as first-line therapy or in refractory-relapsed patients. In particular, a considerable rate of complete remission can be achieved in untreated patients. Myelosuppression represents the major side-effect.