Galassi Rossana, Luciani Lorenzo, Gambini Valentina, Vincenzetti Silvia, Lupidi Giulio, Amici Augusto, Marchini Cristina, Wang Junbiao, Pucciarelli Stefania
School of Science and Technology, University of Camerino, Camerino, Italy.
School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy.
Front Chem. 2021 Jan 11;8:602845. doi: 10.3389/fchem.2020.602845. eCollection 2020.
A class of phosphane gold(I) compounds, made of azoles and phosphane ligands, was evaluated for a screening on the regards of Breast Cancer cell panels (BC). The compounds possess N-Au-P or Cl-Au-P bonds around the central metal, and they differ for the presence of aprotic or protic polar groups in the azoles and/or the phosphane moieties to tune their hydrophilicity. Among the six candidates, only the compounds having the P-Au-N environment and not displaying neither the hydroxyl nor carboxyl groups in the ligands were found active. The compounds were screened by MTT tests in SKBR3, A17, and MDA-MB231 cancer cells, and two compounds (namely the 4,5-dicyano-imidazolate-1yl-gold(I)-(triphenylphosphane, 5, and 4,5-dichloro-imidazolate-1yl-gold(I)-triphenylphosphane, 6) were found very cytotoxic, with the most active with an IC value of 3.46 μM in MDA-MB231 cells. By performing enzymatic assays in the treated cells lysates, the residual enzymatic activity of dihydrofolate reductase (DHFR) has been measured after cell treatment for 4 or 12 h in comparison with control cells. Upon 12 h of treatment, the activity of DHFR was significantly reduced in both SKBR3 and A17 cells by compounds 5 and 6, but not in human MDA-MB231 cells; interestingly, it was found remarkably high after 4 h of treatment, revealing a time dependence for the DHFR enzymatic assays. The DHFR inhibition data have been compared to those for the thioredoxin reductase (TrxR), the most recognized molecular target for gold compounds. For this latter, similar residual activities (i.e., 37 and 49% for the match of SKBR3 cells and compound 5 or 6, respectively) were found. Binding studies on the regards of ct-DNA (calf-thymus-DNA) and of plasma transporters proteins, such as BSA (bovine serum albumin) and ATF (apo transferrin), were performed. As expected for gold compounds, the data support strong binding to proteins (K values range: 1.51 ÷ 2.46 × 10 M) and a weaker interaction with ct-DNA's minor groove (K values range: 1.55 ÷ 6.12 × 10 M).
对一类由唑类和膦配体组成的膦金（I）化合物进行了乳腺癌细胞系（BC）方面的筛选评估。这些化合物在中心金属周围具有N-Au-P或Cl-Au-P键，并且由于唑类和/或膦部分中存在非质子或质子极性基团以调节其亲水性而有所不同。在六个候选化合物中，仅发现具有P-Au-N环境且配体中既不显示羟基也不显示羧基的化合物具有活性。通过MTT试验在SKBR3、A17和MDA-MB231癌细胞中对这些化合物进行了筛选，发现两种化合物（即4,5-二氰基-咪唑-1-基-金（I）-（三苯基膦），5，和4,5-二氯-咪唑-1-基-金（I）-三苯基膦，6）具有很强的细胞毒性，其中活性最高的在MDA-MB23细胞中的IC值为3.46μM。通过在处理后的细胞裂解物中进行酶活性测定，与对照细胞相比，在细胞处理4小时或12小时后测量了二氢叶酸还原酶（DHFR）的残余酶活性。处理12小时后，化合物5和6使SKBR3和A17细胞中的DHFR活性均显著降低，但在人MDA-MB231细胞中未降低；有趣的是，在处理4小时后发现其活性显著升高，这表明DHFR酶活性测定存在时间依赖性。已将DHFR抑制数据与硫氧还蛋白还原酶（TrxR）的数据进行了比较，硫氧还蛋白还原酶是金化合物最公认的分子靶点。对于后者，发现了相似的残余活性（即，SKBR3细胞与化合物5或6匹配时分别为37%和49%）。进行了关于小牛胸腺DNA（ct-DNA）以及血浆转运蛋白如牛血清白蛋白（BSA）和脱铁转铁蛋白（ATF）的结合研究。正如金化合物所预期的那样，数据支持其与蛋白质的强烈结合（K值范围：1.51÷2.46×10⁶M）以及与ct-DNA小沟的较弱相互作用（K值范围：1.55÷6.12×⁶M）。
