Selective Targeting of Regulated Rhabdomyosarcoma Cells by Trinuclear Ruthenium(II)–Arene Complexes

The use of benzimidazole-based trinuclear ruthenium(II)–arene complexes (1–3) to selectively target the rare cancer rhabdomyosarcoma is reported. Preliminary cytotoxic evaluations of the ruthenium complexes in an eight-cancer cell line panel revealed enhanced, selective cytotoxicity toward rhabdomyosarcoma cells (RMS). The trinuclear complex 1 was noted to show superior short- and long-term cytotoxicity in RMS cell lines and enhanced selectivity relative to cisplatin. Remarkably, 1 inhibits the migration of metastatic RMS cells and maintains superior activity in a 3D multicellular spheroid model in comparison to that of the clinically used cisplatin. Mechanistic insights reveal that 1 effectively induces genomic DNA damage, initiates autophagy, and prompts the intrinsic and extrinsic apoptotic pathways in RMS cells. To the best of our knowledge, 1 is the first trinuclear ruthenium(II) arene complex to selectively kill RMS cells in 2D and 3D cell cultures.


Supporting Information
Selective Targeting of Regulated Rhabdomyosarcoma

Cells by Trinuclear Ruthenium(II)-Arene Complexes
Athi Welsh, Karabo Serala, Sharon Prince and Gregory S. Smith* a.Department of Chemistry, University of Cape Town, Rondebosch, 7700, South Africa b.Department of Human Biology, University of Cape Town, Faculty of Health Science, Observatory, 7935, South Africa *Corresponding Author: Professor Gregory S. Smith, Email: Gregory.Smith@uct.ac.za

Figure S4 :
Figure S4: The HR-ESI Mass Spectrum of 1 recorded in the positive-ion mode (+ve), with the assigned base peak.

Figure S5 :
Figure S5: The HR-ESI Mass Spectrum of 2 recorded in the positive-ion mode (+ve), with the assigned base peak.

Figure S6 :
Figure S6: The HR-ESI Mass Spectrum of 3 recorded in the positive-ion mode (+ve), with the assigned base peak.

Figure S8 :
Figure S8: The HPLC chromatogram of the complex 2.

Figure S19 :
Figure S19: The percentage cell survival of MCF-7 breast cancer cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S20 :
Figure S20: The percentage cell survival of MDA-MB-231 breast cancer cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S21 :
Figure S21: The percentage cell survival of PANC-1 pancreatic cancer cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S22 :
Figure S22: The percentage cell survival of CFPAC-1 pancreatic cancer cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S23 :
Figure S23: The percentage cell survival of RD rhabdomyosarcoma cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S24 :
Figure S24: The percentage cell survival of RH-30 rhabdomyosarcoma cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S25 :
Figure S25: The percentage cell survival of FG-0 non-tumorigenic cells as determined by MTT assays.The cancer cells were treated with either 0.1% DMSO (vehicle control), the test compounds (1 and 2) at concentrations between 5 µM and 35 µM.* = p ≤ 0.05, thus statistically significant and ** = p ≤ 0.01, thus very statistically significant.

Figure S26 :
Figure S26: Representative images (10X; EVOS M5000 imaging System) of the morphology of RD and RH-30 cells after treatment with either the complex 1 (at ½ IC50 or IC50) or cisplatin for 48 h.