Synthesis, characterization, and in vitro antitumor properties of tris(hydroxymethyl)phosphine copper(I) complexes containing the new bis(1,2,4-triazol-1-yl)acetate ligand

The new sodium bis(1,2,4-triazol-1-yl) acetate ligand, Na[HC(CO2)(tz)(2)], has been prepared in methanol solution by using 1,2,4-triazole, dibromoacetic acid, and NaOH. Treatment of the [Cu(CH3CN)(4)][PF6] acceptor with Na[HC( CO2)(tz)(2)] or Na[HC(CO2)[(pz(Me2))(2)], in the presence of the tris(hydroxymethyl) phosphine coligand in methanol/acetonitrile solutions produced unprecedented mononuclear copper(I) complexes of the type [L-n]Cu[ P(CH2OH)(3)](2) (L-1, 2; L-2, 3) and [(CH3CN)(2)Cu(P(CH2OH)(3))(2)] PF6, 4. These compounds have been characterized by elemental analyses, FTIR, ESI-MS, and multinuclear (H-1 and P-31) NMR spectral data. The new copper(I) complexes were tested for their cytotoxic properties against a panel of several human tumor cell lines. The results reported here indicate that all the complexes showed in vitro antitumor activity similar or better than that of cisplatin, the most used metal-based antitumor drug. In particular, [HC(CO2)(pzMe(2))(2)]Cu[P(CH2OH)(3)](2), 3 showed IC50 values markedly lower than the reference compound against all tumor cell lines. Chemosensitivity tests performed on cisplatin sensitive and resistant cell lines have demonstrated that all these Cu(I) complexes were able to overcome cisplatin resistance, supporting the hypothesis of a different mechanism of action compared to that exhibited by the reference drug. Flow cytometric analysis on 2008 human ovarian carcinoma cells revealed that complex 3, chosen as the best candidate, induced a marked enlargement of both cell size and granularity, and a significant increase in the fraction of G2/M cells that, differently from cisplatin, was not accompanied by the appearance of a relevant sub-G1 fraction. Besides, no evidence of caspase-3 activation was detected in cells treated with complex 3. We hypothesize that the cytotoxic activity of the new copper(I) complex may be correlated to its ability to trigger paraptosis, a nonapoptotic mechanism of cell death.

通过使用1,2,4 - 三唑、二溴乙酸和氢氧化钠在甲醇溶液中制备了新的双（1,2,4 - 三唑 - 1 - 基）乙酸钠配体Na[HC(CO₂)(tz)(₂)]。在甲醇/乙腈溶液中，用Na[HC(CO₂)(tz)(₂)]或Na[HC(CO₂)[(pz(Me₂))(₂)]处理[Cu(CH₃CN)(₄)][PF₆]受体，在三（羟甲基）膦共配体存在下，生成了前所未有的单核铜（I）配合物[L - n]Cu[P(CH₂OH)(₃)](₂)（L - 1，2；L - 2，3）和[(CH₃CN)(₂)Cu(P(CH₂OH)(₃))(₂)]PF₆，4。这些化合物已通过元素分析、傅里叶变换红外光谱（FTIR）、电喷雾质谱（ESI - MS）以及多核（¹H和³¹P）核磁共振光谱数据进行了表征。对新的铜（I）配合物针对一组几种人类肿瘤细胞系进行了细胞毒性测试。此处报道的结果表明，所有配合物在体外显示出与顺铂（最常用的金属基抗肿瘤药物）相似或更好的抗肿瘤活性。特别是，[HC(CO₂)(pzMe(₂))(₂)]Cu[P(CH₂OH)(₃)](₂)，3对所有肿瘤细胞系显示出的IC₅₀值明显低于对照化合物。对顺铂敏感和耐药细胞系进行的化学敏感性测试表明，所有这些铜（I）配合物都能够克服顺铂耐药性，这支持了与对照药物相比其作用机制不同的假设。对2008人类卵巢癌细胞的流式细胞术分析表明，被选作最佳候选物的配合物3诱导细胞大小和颗粒度显著增大，并且G₂/M期细胞比例显著增加，与顺铂不同的是，没有伴随出现相关的亚G₁期细胞比例。此外，在配合物3处理的细胞中未检测到半胱天冬酶 - 3激活的证据。我们假设新的铜（I）配合物的细胞毒性活性可能与其触发副凋亡（一种非凋亡性细胞死亡机制）的能力相关。