Model Amphipathic Peptide Coupled with Tacrine to Improve Its Antiproliferative Activity

Abstract

Drug repurposing and drug combination are two strategies that have been widely used to overcome the traditional development of new anticancer drugs. Several FDA-approved drugs for other indications have been tested and have demonstrated beneficial anticancer effects. In this connection, our research group recently reported that Tacrine, used to treat Alzheimer’s Disease, inhibits the growth of breast cancer MCF-7 cells both alone and in combination with a reference drug. In this view, we have now coupled Tacrine with the model amphipathic cell-penetrating peptide (CPP) MAP, to ascertain whether coupling of the CPP might enhance the drug’s antiproliferative properties. To this end, we synthesized MAP through solid-phase peptide synthesis, coupled it with Tacrine, and made a comparative evaluation of the parent drug, peptide, and the conjugate regarding their permeability across the blood-brain barrier (BBB), ability to inhibit acetylcholinesterase (AChE) in vitro, and antiproliferative activity on cancer cells. Both MAP and its Tacrine conjugate were highly toxic to MCF-7 and SH-SY5Y cells. In turn, BBB-permeability studies were inconclusive, and conjugation to the CPP led to a considerable loss of Tacrine function as an AChE inhibitor. Nonetheless, this work reinforces the potential of repurposing Tacrine for cancer and enhances the antiproliferative activity of this drug through its conjugation to a CPP.

New Peptide Functionalized Nanostructured Lipid Carriers with CNS Drugs and Evaluation Anti-proliferative Activity

“…In a previous work conducted by our group, we demonstrated that conjugation of MAP with TAC resulted in increased toxicity against both MCF-7 and SH-SY5Y cell lines [17]. Moreover, this TAC-MAP conjugated activity was further studied with successful incorporation onto NLC [18].…”

“…MAP (KLALKLALKALKAALKLA-NH 2 ), TAC-MAP, and RAS-MAP were previously synthetized by our research group as described in refs. [17,28]. Briefly, MAP was synthetized through Fmoc/tBu solid-phase peptide synthesis (SPPS) methodologies assisted with microwave (MW) energy, using a Liberty Microwave Peptide Synthesizer.…”

A Second Life for MAP, a Model Amphipathic Peptide

“…The antiproliferative activity against different tumor cell lines (breast cancer MCF-7 and neuroblastoma SH-SY5Y) was observed with MAPs conjugated with tacrine. The authors observed a decrease of 50% cell viability at a concentration of 2.5 µM for SH-SY5Y and 5 µM for MCF-7, and with loss of morphological appearance and high cell death at 20 µM [ 66 ]. The same authors further observed an increase in the antiproliferative effect of MAPs conjugated with the central nervous system (tranylcypromine and rasagiline) against neuroblastoma cell line SH-SY5Y and colorectal adenocarcinoma Caco-2 cell lines when compared to MAPs alone and a MAP derivate (Lys(N 3 )-MAP) [ 67 ].…”

“…The results demonstrated a pH-dependent surface binding and internalization to cell membrane [ 68 ]. This nanoparticle and MAP association was further evaluated in two complementary works conducted by Silva et al First, it was demonstrated that the encapsulation of conjugated Tacrine-MAP into lipid nanoparticles lead to a decrease in cell viability against two cancer cell lines, SH-SY5Y and MCF-7, compared to treatment with free Tacrine-MAP conjugate [ 66 ]. In the following work, the authors evaluated two more conjugates, tranylcypromine-MAP and rasagiline-MAP, encapsulated into the same lipid nanoparticles in vitro.…”

Tacrine First-Phase Biotransformation and Associated Hepatotoxicity: A Possible Way to Avoid Quinone Methide Formation

“…Instead, mice or dogs seem to be more promising, as they generate higher levels of the 7-OH-TA metabolite, 13 in accordance with in vivo biotransformation of tacrine in humans. 11 As tacrine is widely used as a scaffold for the development of a multitude of compounds against neurodegenerative diseases, 14 malaria, 15 and cancer, 16 we hypothesize that compounds avoiding such toxic biotransformation (i.e., not resulting in the formation of 7-OH-TA) could serve as more favorable drug candidates. To avoid such an unwanted biotransformation, we masked the problematic 7 position by developing 7-methoxytacrine (7-MEOTA) and 7-phenoxytacrine (7-PhO-TA) (Figure 1B), which we extensively characterized.…”