Cytocidal Antitumor Effects against Human Ovarian Cancer Cells Induced by B-Lactam Steroid Alkylators with Targeted Activity against Poly (ADP-Ribose) Polymerase (PARP) Enzymes in a Cell-Free Assay.

Nikolaos Nikoleousakos,Vasiliki Sarli,Dimitrios T Trafalis,Elena G Geromichalou,Aikaterini Polonifi,Constantinos E Alifieris,Panagiotis Dalezis,Maria V Deligiorgi,Sofia Sagredou

doi:10.3390/biomedicines9081028

Nikolaos Nikoleousakos, Vasiliki Sarli + Show 7 more

Open Access

https://doi.org/10.3390/biomedicines9081028

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Abstract

We evaluated three newly synthesized B-lactam hybrid homo-aza-steroidal alkylators (ASA-A, ASA-B and ASA-C) for their PARP1/2 inhibition activity and their DNA damaging effect against human ovarian carcinoma cells. These agents are conjugated with an alkylating component (POPA), which also served as a reference molecule (positive control), and were tested against four human ovarian cell lines in vitro (UWB1.289 + BRCA1, UWB1.289, SKOV-3 and OVCAR-3). The studied compounds were thereafter compared to 3-AB, a known PARP inhibitor, as well as to Olaparib, a standard third-generation PARP inhibitor, on a PARP assay investigating their inhibitory potential. Finally, a PARP1 and PARP2 mRNA expression analysis by qRT-PCR was produced in order to measure the absolute and the relative gene expression (in mRNA transcripts) between treated and untreated cells. All the investigated hybrid steroid alkylators and POPA decreased in vitro cell growth differentially, according to the sensitivity and different gene characteristics of each cell line, while ASA-A and ASA-B presented the most significant anticancer activity. Both these compounds induced PARP1/2 enzyme inhibition, DNA damage (alkylation) and upregulation of PARP mRNA expression, for all tested cell lines. However, ASA-C underperformed on average in the above tasks, while the compound ASA-B induced synthetic lethality effects on the ovarian cancer cells. Nevertheless, the overall outcome, leading to a drug-like potential, provides strong evidence toward further evaluation.

Highlights

The second most common malignancy after breast cancer in women over the age of 40 is ovarian cancer
The tested aza-steroidal alkylators azepin-5-yl 3-(4-(bis(2-chloroethyl)amino) phenoxy)propanoate (ASA-A) and ASA-B, in terms of their cytostatic and cytotoxic activity, presented a significant selectivity against the ovarian human cancer cells, since they generated significantly lower cytostatic (IG50 and the 100% cell growth inhibition (TGI)) and cytotoxic (IC50) effects on normal human lung fibroblasts MRC-5
Recent studies associate it with epithelial to mesenchymal transition (EMT), a biological phenomenon involved in the early progression of cancer metastasis, and the modulation of EMT regulators like Vimentin, Claudin-1 and other transcription factors, playing a dual role in EMT

Summary

Introduction

The second most common malignancy after breast cancer in women over the age of 40 is ovarian cancer. As of 2018, ovarian cancer was the seventh most common cancer worldwide in women and the fifth leading cause of cancer-related death in the same group. Due to the lack of a definitive screening tool and the vague signs and symptoms that can “masquerade” as other non-malignant conditions, curative and survival trends have not changed significantly, as early diagnosis remains a challenge [1]. The most common treatment consists of surgery and a combination of platinum/taxane chemotherapy [2]. The treatment is often ineffective, since a major percentage of patients acquire resistance to chemotherapy regimens.

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