Permeability evaluation of gemcitabine-CPP6 conjugates in Caco-2 cells

Abstract

Cancer is one of the most alarming diseases due to its high mortality and still increasing incidence rate. Currently available treatments for this condition present several shortcomings and new options are continuously being developed and evaluated, aiming at increasing the overall treatment efficiency and reducing associated adverse side effects. Gemcitabine has proven activity and is used in chemotherapy. However, its therapeutic efficiency is limited by its low bioavailability as a result of rapid enzymatic inactivation. Additionally, tumor cells often develop drug resistance after initial tumor regression related to transporter deficiency. We have previously developed three gemcitabine conjugates with cell-penetrating hexapeptides (CPP6) to facilitate intracellular delivery of this drug while also preventing enzymatic deamination. The bioactivity of these new prodrugs was evaluated in different cell lines and showed promising results. Here, we assessed the absorption and permeability across Caco-2 monolayers of these conjugates in comparison with gemcitabine and the respective isolated cell-penetrating peptides (CPPs). CPP6-2 (KLPVMW) and respective Gem-CPP6-2 conjugate showed the highest permeability in Caco-2 cells.

Evaluation of Antiviral Activity of Gemcitabine Derivatives against Influenza Virus and Severe Acute Respiratory Syndrome Coronavirus 2

“…Irrespective of their availability in antiviral experiments, a recent report suggested that gemcitabine as an antitumor compound suppresses Caco-2 cancer cell proliferation by 40−50% at a wide range of concentrations between 0.1 μM and 1 mM during 3 day incubation. 32 In a similar manner, our experiments showed that incubation of MDCK cells with gemcitabine gradually decreased cell viability at concentrations above 3.3 μM (Figure 1C). Moreover, in spite of its profound EC 50 values against influenza viruses (0.3−0.7 μM), antiviral activity failed to recover over 90% cell viability of the virusinfected cells (Table 1).…”

“…As an example, Caco-2 human colorectal adenocarcinoma cells are frequently used as susceptible cells for infection of influenza virus or SARS-CoV-2. Irrespective of their availability in antiviral experiments, a recent report suggested that gemcitabine as an antitumor compound suppresses Caco-2 cancer cell proliferation by 40–50% at a wide range of concentrations between 0.1 μM and 1 mM during 3 day incubation . In a similar manner, our experiments showed that incubation of MDCK cells with gemcitabine gradually decreased cell viability at concentrations above 3.3 μM (Figure C).…”

The role of cell‐penetrating peptides in potential anti‐cancer therapy

“…The hydrophobic interaction of CPPs also has a positive effect on the penetration ability of CPPs. The aromatic tryptophan can be considered hydrophobic, and the penetration ability of CPPs is reported to be positively correlated with the number of tryptophan residues 28 . Arginine residues play an important role in cell membrane interactions, uptake mechanisms and hydrophobic α‐helix structures, which was demonstrated by the comparison of the delivery efficiencies of TP10 and Pen‐Arg 29 .…”

“…The aromatic tryptophan can be considered hydrophobic, and the penetration ability of CPPs is reported to be positively correlated with the number of tryptophan residues. 28 Arginine residues play an important role in cell membrane interactions, uptake mechanisms and hydrophobic α-helix structures, which was demonstrated by the comparison of the delivery efficiencies of TP10 and Pen-Arg. 29 At the same time, the concentration of CPP affected the uptake mechanism of CPP, which means that high concentrations of primary hydrophobic CPP were more likely to penetrate cell membrane directly, whereas endocytosis was the primary absorption mechanism at the low concentrations.…”

Prediction of Drug Synergism between Peptides and Antineoplastic Drugs Paclitaxel, 5-Fluorouracil, and Doxorubicin Using In Silico Approaches

“…The generic GastroPlus ® ACAT model provided reasonable predictions especially for biopharmaceutical classification system (BCS) class 1 compounds [20]. In addition, the ability of PBPK models to predict oral PK will also improve, providing a better tool for the discovery and development of new medicines [21][22][23][24], as drug combinations or drug synergism.…”