AIM To study the effects of arsenic trioxide and HCPT on different degrees of differentiated gastric cancer cells (SGC-7901, MKN-45, MKN-28)with respect to both cytotoxicity and induction of apoptosis in vitro. ~ODS The cytotoxicity of As2O3 and HCPT on gastric cancer cells was determined by MTTassay. Morphologic changes of apoptosis of gastric cancer cells were observed by light microscopy and transmission electron microscopy. Apoptosis and cell cycle changes of gastric cancer cells induced by HCPT and As2O3 were investigated by TUNEL method and flow cytometry. RESULTS As2O3 and HCPT had remarkable cytotoxic effects on different degrees of differentiated gastric cancer cells. The IC50 of As2O3 on well differentiated gastric cancer cell MKN-28, moderately differentiated gastric cancer cell SGC-7901, and poorly differentiated gastric cancer cell MKN-28 were 8. 91 μmol/L, 10. 57 μmol/L, and 11.65 μmol/L, respectively. The IC50 of HCPT on MKN-28, SGC-7901, and MKN-45 were 9. 35 rg/L, 10. 21 rg/L, and 12. 63 mg/L respectively after 48 h treatment. After 12 h of exposure to both drugs, gastric cancer cells exhibited morphologic features of apoptosis, including cell shrinkage, nuclear condensation,and formation of apoptotic bodies. A typical subdiploid peak before G0/G1 phase was observed by flow cytometry. The apoptotic rates of SGC7901, MKN-45, and MKN-28 were 13. 84%, 22.52%, and 9. 68%, respectively after 48 h exposure to 10 μmol/L As2O3. The apoptotic rates of SGC-7901, MKN-45, and MKN-28 were 21.88%, 12.35%, and 30. 26%, respectively after 48 h exposure to 10 mg/L HCPT. The apoptotic indice were 7% - 15% as assessed by TUNEL method. The effect of As2O3 on SGC-7901 showed remarkable cell cycle specificity, which induced cell death in G1 phase, and blocked G2/M phase. HCPT also showed a remarkable cell cycle specificity, by inducing cell death and apoptosis in G1 phase and arrest of proliferation at S phase. CONCLUSION AS2O3 and HCPT exhibit significant cytotoxicity on gastric cancer cells by induction of apoptosis. As2O3 and HCPT might have a promising prospect in the treatment of gastric cancer, which needs to be further studied.

以三氧化二砷为主治疗急性早幼粒细胞性白血病的临床观察和随访研究

三氧化二砷(As2O3 )是治疗小儿急性早幼粒细胞白血病(APL)有效的药物,它诱导早幼粒细胞分化和凋亡.成人应用As2O3治疗APL的报告较多[1],而对小儿APL的报道很少[2].2000年2月-2004年12月对14例小儿APL应用As2O3进行治疗,报告如下.

Objective: To detect the effect of arsenic trioxide or ATRA on APL cells or HL-60 cells and to investigate the mechanism of the hyperleukocytosis and detect the cross resistance between ATRA and arsenic trioxide. Methods: The number of promyelocytes or more matured granulocytes were counted by regular method, MTT test was used to measure the proliferation of HL-60 cells or APL cells, flow cytometry analysis to measure the apoptosis, NBT method to detect the differentiation of HL-60 cells or APL cells. Results: The proliferation of primary APL cells or HL-60 cells could be inhibited in vitro by either arsenic trioxide or ATRA, which could induce obvious apoptosis or obvious differentiation of primary APL cells or HL-60 cells. Inhibition of proliferation or apoptosis of ATRA resistant HL-60 cells were achieved by exposure toarsenic trioxide in vitro. On the other hand, the results of in vivo treatment showed that arsenic trioxide also induce of hyperleukocytosis. Conclusion: The results indicated that the hyperleukocytosis induced by ATRA is not contributed to the mechanism of more differentiation than apoptosis, there was not cross resistance between ATRA and arsenic trioxide.

三氧化二砷与维生素C治疗多发性骨髓瘤骨折病人的副反应观察

多发性骨髓瘤(MM)是B淋巴细胞恶性肿瘤,发病率居血液恶性肿瘤第二位,其常见并发症是骨折,治疗以化疗和干细胞移植为主,但缓解率低,难治性、复发性病例缓解率更低.近年来,国外采用三氧化二砷(As2O3)联合维生素C治疗MM有一定疗效[1].我们观察了As2O3联合维生素C治疗难治性或复发性MM病人35例的副反应.现报告如下.

Objective To investigate therapeutic action of verapamil on QT prolongation induced by arsenic trioxide (As2O3) in guinea pig and to further explore its possible mechanism. Methods Different doses of As2 O3 was infused intravenously to observe the changes of QT interval on the electrocardiogram (ECG) at different times in guinea pig. Patchclamp technique and laser scanning confocal microscopy were utilized to study the action of As2 O3 on action potential duration (APD),L-type calcium current (ICa-L ), rapid delayed rectifier potassium current (IKr) and intracellular calcium concentration ([Ca2+]i) of guinea pig myocytes. At the same time, verapamil was applied preliminarily to evaluate effects of verapamil on changes of the above index induced by As2O3. Results Intravenous administration of As2 O3 at the dose of 1.6mg/kg and 0.8mg/kg prolonged QT interval on ECG obviously in guinea pig hearts dose dependently and time dependently. QTc (corrected QT interval) was progressively prolonged in the 2-hour period of intravenous infusion of 1.6mg/kg As2O3 from (328.5 ± 30.9)ms of control to (388.4 ± 31.3)ms at 2h following As2O3 ( P ＜ 0.01) .When verapamil was pretreated for 5min, then 1.6mg/kg As2 O3 was added, the results showed that QTe was shorter in verapamil-treatment group (357.3±21.4)ms than that in As2O3 group (388.4±31.3)ms (P＜0.05) at 2h. Confocal experiments showed that in normal Tyrode solution, As2 O3 (1μmol/L and 10μmol/L) had no obvious effects on resting [Ca2+]i (P＞0.05) in guinea pig cardiomyocytes, however, 10μmol/L As2 O3 could markedly enhance [Ca2+]i increase induced by KCl 60mmol/L and the peak value increased from 903.4±369.4 to 1674.6±563.2 ( P＜0.05). The action of elevating [Ca2+]icould be blocked by 10μmol/L verapamil incompletely. The patch-clamp studies indicated that As2 O3 at concentration of 10μmol/L prolonged APD50 from (263.6 -±75.2)ms to (523.9±47.8)ms (P＜0.01) and APD90 from (277.5 ± 77.5)ms to (536.3 ±49.6)ms (P ＜0.01) ,and increased ICa-L from (- 6.0±1.5)pA/pF to (-8.7±2.0)pA/pF (P＜0.01) at 0mV and also reduced IKr from (6.7±1.8)pA/pF to (4.5±1.8)pA/pF (P＜0.05). However, 10μmol/L verapamil could modulate prolonging APD50 from (523.9 ± 47.8) ms to (340.4±83.8) ms ( P＜0.01) and APD90 from (536.3 ±49.6)ms to (348.9 ± 85.5)ms (P＜0.01) and correct increasing Ica-L induced by 10μmol/L As2O3 from (-8.7±2.0)pA/pF to ( - 6.6±1.4)pA/pF (P＜0.05) at 0mV. Conclusion As2O3 could induce prolongation of the QT interval on the ECG in guinea pig hearts and the ionic mechanism is associated with increasing Ica-L and inhibiting IKr/HERG. Verapamil may be useful in normalizing QT prolongation during As2 O3 therapy by decreasing Ica-L and [Ca2+]iof ventricular myocytes in guinea pig.

全反式维甲酸和三氧化二砷治疗急性早幼粒细胞白血病APL的进展

一、引言急性早幼粒细胞白血病(Acute Promyelocytic Leukemia,APL)是FAB分型中急性非淋巴细胞白血病(Acute nonlymphocytic Leukemia ,ANLL)的M3亚型,占所有ANLL的10%～15%,具有独特的临床表现,细胞形态学,细胞遗传学和分子生物学特征.近十年的研究表明APL是第一个联合应用全反式维甲酸(all-trans retinoic acid,ATRA),三氧化二砷(Aa2O3)和化疗取得成功的人类恶性肿瘤,开创了诱导分化治疗的新篇章[1-3].本文总结了近年对APL分子发病机理,ARA和A2O3诱导分化/凋亡以及联合化疗的临床应用及其作用机制的研究概况.