On the formation of 4-[N,N-bis(2-chloroethyl)amino]phenyl acetic acid esters of hecogenin and aza-homo-hecogenin and their antileukemic activity

Azasteroid Alkylators as Dual Inhibitors of AKT and ERK Signaling for the Treatment of Ovarian Carcinoma

(1) Background: Previous findings show that lactam steroidal alkylating esters display improved therapeutic efficacy with reduced toxicity. The aim of this study was to evaluate the anticancer activity of two newly synthesized aza-steroid alkylators (ENGA-L06E and ENGA-L08E) against human ovarian carcinoma cells, and consequently, the dual inhibition of RAS/PI3K/AKT and RAS/RAF/MEK/ERK signaling pathways, both of which are closely associated with ovarian cancer; (2) Methods: The in vitro cytostatic and cytotoxic effects of ENGA-L06E and ENGA-L08E were evaluated in a panel of five human ovarian cancer cell lines, as well as in in vivo studies. ENGA-L06E and ENGA-L08E, in addition to another two aniline-mustard alkylators, POPAM and melphalan (L-PAM), were utilized in order to determine the acute toxicity and antitumor efficacy on two human ovarian xenograft models. Also, in silico studies were performed in order to investigate the dual inhibition of ENGA-L06E and ENGA-L08E on RAS/PI3K/AKT and RAS/RAF/MEK/ERK signaling pathways; (3) Results: Both, in vitro and in vivo studies demonstrated that ENGA-L06E and ENGA-L08E were significantly more effective with a lower toxicity profile in comparison to POPAM and L-PAM alkylators. Moreover, in silico studies demonstrated that the two new aza-steroid alkylators could act as efficient inhibitors of the phosphorylation of AKT and ERK1/2 molecules; and (4) Conclusions: Both ENGA-L06E and ENGA-L08E demonstrated high anticancer activity through the inhibition of the PI3K-AKT and KRAS-ERK signaling pathways against human ovarian carcinoma, and thus constituting strong evidence towards further clinical development.

Novel pregnenolone derivatives modulate apoptosis via Bcl-2 family genes in hepatocellular carcinoma in vitro

A series of pregnenolone derivatives were synthesized and assessed for anti-cancer activity against hepatocellular carcinoma cell line (HepG2). The synthesized hetero-steroids (compounds 3, 4, 5, 6, 7, 8a and 8b) were evaluated for their cytotoxic activities using MTT (3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assay. Apoptotic activity was assessed using dual acridine orange/ethidium bromide staining method and DNA fragmentation assay. Pro-apoptotic genes (Bax and Bak) and anti-apoptotic genes (Bcl-2 and Bcl-xL) were analyzed using quantitative real time PCR. The results revealed that compounds 4 and 6 displayed cytotoxic activity (IC_50s, 36.97 ± 2.18 and 18.46 ± 0.64 μM, respectively), while compounds 5 and 7 exhibited weak cytotoxic activity (IC_50s, 93.87 ± 8.30 μM and 93.48 ± 4.14 μM, respectively). All synthesized heterocyclic pregnenolone derivatives induced apoptosis through DNA fragmentation. Compounds 4 and 6 increased early and late apoptotic cell percentages while compounds 3, 5, 7 and 8b increased either early or late apoptotic cell percentage. Moreover, compounds 3, 6 and 8b up-regulated the expression level of Bak gene. On the other hand, compounds 4, 5, 7 and 8a down-regulated the Bcl-2 expression level, besides, compounds 5, 7 and 8a down-regulated the Bcl-xL expression level. Compounds 5, 7, 8a and 8b increased the Bak/Bcl-xL ratio, besides, compound 8a raised the Bax/Bcl-xL ratio whereas compound 5 elevated Bax/Bcl-2 and Bak/Bcl-2 ratios. The present work introduced novel pro-apoptotic pregnenolone derivatives that acted against HepG2 cells through DNA fragmentation, apoptotic morphological changes and were able to increase the pro-apoptotic/anti-apoptotic ratios of Bcl-2 family genes. This study particularly revealed that the cytotoxic compound 4 is the most promising pro-apoptotic compound among other synthesized derivatives where it induced apoptosis (late and early) through the down-regulation of Bcl-2 gene expression level.

Synthesis and evaluation of new steroidal lactam conjugates with aniline mustards as potential antileukemic therapeutics

Alkylating agents are still nowadays one of the most important classes of cytotoxic drugs, which display a wide range of therapeutic use for the treatment of various cancers. We have synthesized and tested four hybrid homo-azasteroidal alkylating esters for antileukemic activity against five sensitive to alkylating agents human leukemia cell lines in vitro and against P388 murine leukemia in vivo. Comparatively, melphalan and 3-(4-(bis(2-chloroethyl)amino)phenoxy)propanoic acid (POPAM) were also examined. All the homo-aza-steroidal alkylators showed relatively lower acute toxicity, very promising and antileukemic activity both in vitro and in vivo.

Steroid-linked nitrogen mustards as potential anticancer therapeutics: a review

Nitrogen mustards, an important class of drugs for cancer therapy, are known as DNA alkylating agents. The nitrogen mustards are highly reactive and, as a consequence, lack of selectivity and produce several adverse side effects. In order to minimize these undesirable effects, the attachment of nitrogen mustards to a steroidal hormone with affinity for its receptor can lead to highly selective and less toxic antineoplastic therapeutics. This review will focus on the design, synthesis and evaluation of such steroid-nitrogen mustard hybrids as antineoplastic agents. Among these compounds, modified steroids with aromatic nitrogen mustards linked by an ester function were found to have better DNA alkylating properties, improved selectivity as well as low toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Synthesis and antileukemic activity of novel 4-(3-(piperidin-4-yl) propyl)piperidine derivatives

To explore the anticancer effect associated with the piperidine framework, several (substituted phenyl) {4-[3-(piperidin-4-yl)propyl]piperidin-1-yl} methanone derivatives 3(a-i) were synthesized. Variation in the functional group at N-terminal of the piperidine led to a set of compounds bearing amide moiety. Their chemical structures were confirmed by (1) H NMR, IR and mass spectra analysis. Among these, compounds 3a, 3d and 3e were endowed with antiproliferative activity. The most active compound among this series was 3a with nitro and fluoro substitution on the phenyl ring of aryl carboxamide moiety, which inhibited the growth of human leukemia cells (K562 and Reh) at low concentration. Comparison with other derivative (3h) results shown by LDH assay, cell cycle analysis and DNA fragmentation suggested that 3a is more potent to induce apoptosis.