Investigation of the role of Bax, p21/Waf1 and p53 as determinants of cellular responses in HCT116 colorectal cancer cells exposed to the novel cytotoxic ruthenium(II) organometallic agent, RM175

• Published in: Cancer chemotherapy and pharmacology 2005-06, Vol.55 (6), p.577-583
• Main Authors: HAYWARD, R. L, SCHORNAGEL, Q. C, TENTE, R, MACPHERSON, J. S, AIRD, R. E, GUICHARD, S, HABTEMARIAM, A, SADLER, P, JODRELL, D. I
• Format: Article
• Language: English
• Subjects: Antineoplastic agents; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; bcl-2-Associated X Protein; Biological and medical sciences; Cell Cycle - drug effects; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Survival - drug effects; Cloning, Molecular; Colorectal Neoplasms - metabolism; Colorectal Neoplasms - pathology; Cyclin-Dependent Kinase Inhibitor p21; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Gastroenterology. Liver. Pancreas. Abdomen; HCT116 Cells; Humans; Immunoblotting; Inhibitory Concentration 50; Medical sciences; Organometallic Compounds - pharmacology; Pharmacology. Drug treatments; Proto-Oncogene Proteins c-bcl-2 - genetics; Proto-Oncogene Proteins c-bcl-2 - metabolism; Ruthenium - pharmacology; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Tumors
• ISSN: 0344-5704; 1432-0843
• DOI: 10.1007/s00280-004-0932-9

Ruthenium(II) organometallic complexes form monofunctional adducts with guanine in DNA in vitro and have a cytotoxic anticancer activity spectrum in preclinical models suggesting lack of cross-resistance with cisplatin. The primary cytotoxic lesion remains to be identified but the downstream mechanism of action is nevertheless of interest. Using isogenic derivatives of the HCT116 colorectal cancer cell line, we investigated the role of p53, p21/WAF1 and Bax in the cellular response to the novel ruthenium(II) organometallic complex RM175, [(eta(6)-C(6)H(5)C(6)H(5))RuCl (H(2)NCH(2)CH(2)NH(2)-N,N')](+) PF(6)(-). Western blotting demonstrated dose-dependent accumulation of p53, Bax and p21/WAF1 within 48 h of the start of RM175 treatment in wild-type HCT116 cells. HCT116 wild-type and Bax-null cells arrested in the G(1) and G(2) phases of the cell cycle. This pattern of cell cycle arrest was not observed in p53-null or in p21/WAF1-null cells. Following RM175 treatment, HCT116 wild-type and p21/WAF1 null cells underwent a dose-dependent induction of apoptosis (Annexin-V and sub-G(1) apoptosis assays). This apoptotic response was not observed in p53-null or Bax-null cells. In short-term sulphorhodamine B assays, the IC(50) for RM175 was 16 microM for p53-null HCT116, and 8 microM for wild-type cells (P