The effects of newly synthesized platinum(IV) complexes on growth and radiosensitization of human malignant tumor cells in vitro

[M. A. Petrović]

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Cilj ovog istraživanja je da se ispita direktno citotoksično dejstvo i potencijalni mehanizam delovanja novosintetisanih kompleksa platine(IV) na više ćelijskih linija humanih tumora (karcinoma pluća-A549, karcinoma dojke-MCF-7 i melanomaHTB140), kao i diferencijalna citotoksičnost u odnosu na normalne, zdrave fibroblaste pluća-MRC-5. Rezultati su upoređeni sa efektima cisplatine (cis-Pt). Ćelije su tretirane 24h nakon zasejavanja, a efekti analiziranih kompleksa platine(IV) su praćeni 6h, 24h i 48h nakon tretmana koncentracijama u opsegu od 5- 100µM. Kompleksi platine(IV) pokazauju vremenski i dozno zavisnu inhibiciju rasta ispitivanih ćelija. Inhibitorni efekti su veoma izraženi na A546 i MCF-7 ćelijskim linijama, a slabi na NTV140, zbog čega su ove ćelije isključene iz daljih istraživanja. Indeks selektivnosti SI˃3 ukazuje na dobru selektivnost kompleksa prema tumorskim ćelijama u odnosu na zdrave MRC-5 ćelije. Analizirani kompleksi imaju statistički značajno antiproliferativno dejstvo na A549 i MCF-7 ćelijama. Tretman IC50 vrednostima ispitivanih kompleksa doveo je do apoptotske ćelijske smrti. Procenat apoptotskih ćelija u tretiranim uzorcima je statistički značajno veći u odnosu na kontrole, dostižući maksimum 48h nakon tretmana. Indukcija apoptoze je povezana sa promenama u ekspresiji proapoptotskog Bax i antiapoptotskog Bcl-2 prteina, kao i njihovim međusobnim odnosom. Kompleksi platine zaustavljaju ćelijski ciklus u S fazi. Tretman A549 i MCF-7 ćelija 1Gy, 2Gy i 4Gy γ zračenja dovodi do slabe inhibicije rasta. Pretretman ovih radiorezistentnih ćelija analiziranim kompleksima platine povećava osetljivost ćelija na γ zračenje.

he aim of this study was to examine the direct cytotoxic effect, as well as the potential mechanism of action of the newly synthesized platinum(IV) complexes on several human tumour cell lines (lung cancer-A549, breast cancer-MCF-7 and melanoma-HTB140), as well as the differential cytotoxicity compared to normal, healthy human fibroblasts-MRC-5. The results were compared with the effects of cisplatin (cis-Pt). The cells were treated 24h after seeding and the effects of the analysed platinum(IV) complexes were monitored 6h, 24h and 48h after treatment with concentrations in the range of 5-100µM. Platinum(IV) complexes show a time- and dose-dependent growth inhibition of all tested cells. The inhibitory effects are very pronounced on A546 and MCF-7 cell lines, and weak on HTB140 and therefore these cells were excluded from further research. The selectivity index SI˃3 indicates a good selectivity of the complex towards tumour cells compared to healthy MRC-5 cells. All analysed complexes showed statistically significant antiproliferative effect on A549 and MCF-7 cells. Treatment with IC50 concentrations of the tested platinum complexes led to apoptotic cell death. The percentage of apoptotic cells was statistically significantly higher compared to untreated controls, reaching a maximum 48h after treatment. Induction of apoptosis is associated with changes in the expression of proapoptotic protein Bax and antiapoptotic protein Bcl-2, as well as their mutual relationship. Platinum(IV) complexes arrested the cell cycle in the S phase. Treatment of A549 and MCF-7 cells with 1Gy, 2Gy and 4Gy of γ radiation results in weak growth inhibition. Pre-treatment of these radioresistant cells with analysed platinum(IV) complexes increases the sensitivity of cells to γ irradiation.

kompleksi platine(IV), cisplatina, antitumorski efekti, klonogeno preživljavanje, ćelijski ciklus, apoptoza, jonizujuće zračenje

platinum(IV) complexes, cisplatin, antitumor effects, clonogenic survival, cell cycle, apoptosis, ionizing radiation

616-006.6:615.277(043.3)

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