Biological Activity and Physicochemical Properties of Dipeptidyl Nitrile Derivatives Against Pancreatic Ductal Adenocarcinoma Cells

The Anti-Tumor Activity of Afatinib in Pancreatic Ductal Adenocarcinoma Cells

BACKGROUND

Pancreatic Ductal Adenocarcinoma (PDAC) is the most common form of pancreatic cancer and leading causes of pancreatic cancer death because of most PDAC patients with advanced unresectable disease at that time, which is remarkably resistant to all forms of chemotherapy and radiotherapy.

OBJECTIVE

PDAC increases the social and patient's family burden. However, the PDAC pathogenesis is not identified. We are trying to uncover the underlying mechanism in the future.

METHODS

In our research, the drug-resistant cell line was successfully induced in the vitro by progressive concentrations of Afatinib, which we named it as BxPC3-AR.

RESULTS

It has been observed that the effect of autophagy was on the resistance of BxPC3-AR to Afatinib.

CONCLUSION

It has been confirmed that autophagy plays a certain role in BxPC3-AR resistance to Afatinib. Our findings provide a new perspective on the role of autophagy in pancreatic ductal adenocarcinoma.

Dipeptidyl nitrile derivatives suppress the Trypanosoma cruzi in vitro infection

Chagas disease affects several countries around the world with health and sanitation problems. Cysteine proteases are essential for the virulence and replication of the Trypanosoma cruzi, being modulated by dipeptidyl nitriles and derivatives. Here, four dipeptidyl nitrile derivatives were assayed in three T. cruzi morphologies and two strains (Tulahuen and Y) using a set of assays: (i) analysis of the inhibitory activity against cysteine proteases; (ii) determination of the cytotoxic activity and selectivity index; (iii) verification of the inhibition of the trypomastigote invasion in the host cell. These compounds could inhibit the activity of cysteine proteases using the selective substrate Z-FR-MCA for the trypomastigote lysate and extracellular amastigotes. Interestingly, these compounds did not present relevant enzymatic inhibition for the epimastigote lysate. Most of the substances were also cytotoxic and selective against the trypomastigotes and intracellular amastigotes. The best compound of the series (Neq0662) could reduce the enzymatic activity of the cysteine proteases for the trypomastigotes and amastigotes. It was equipotent to the benznidazole drug in the cytotoxic studies using these two parasite forms. Neq0662 was also selective for the parasite, and it inhibited the invasion of the mammalian host cell in all conditions tested at 10 μM. The stereochemistry of the trifluoromethyl group was an important factor for the bioactivity when the two diastereomers (Neq0662 and Neq0663) were compared. All-in-all, these results indicate that these compounds could move further in the drug development stage because of its promising bioactive profile.

Synthesis and structure-activity relationship of nitrile-based cruzain inhibitors incorporating a trifluoroethylamine-based P2 amide replacement

The structure-activity relationship for nitrile-based cruzain inhibitors incorporating a P2 amide replacement based on trifluoroethylamine was explored by deconstruction of a published series of inhibitors. It was demonstrated that the P3 biphenyl substituent present in the published inhibitor structures could be truncated to phenyl with only a small loss of affinity. The effects of inverting the configuration of the P2 amide replacement and linking a benzyl substituent at P1 were observed to be strongly nonadditive. We show that plotting affinity against molecular size provides a means to visualize both the molecular size efficiency of structural transformations and the nonadditivity in the structure-activity relationship. We also show how the relationship between affinity and lipophilicity, measured by high-performance liquid chromatography with an immobilized artificial membrane stationary phase, may be used to normalize affinity with respect to lipophilicity.

Apoferritin encapsulation of cysteine protease inhibitors for cathepsin L inhibition in cancer cells

Cysteine proteases play a key role in tumorigenesis causing protein degradation and promoting invasive tumour growth. Cathepsin L is overexpressed in cancer cells and could provide a specific target for delivery of anticancer agents. We encapsulated novel dipeptidyl nitrile based cysteine protease inhibitors (Neq0551, Neq0554 and Neq0568) into biocompatible apoferritin (AFt) protein nanocages to achieve specific delivery to tumours and pH-induced drug release. AFt-encapsulated Neq0554 demonstrated ∼3-fold enhanced in vitro activity (GI₅₀ = 79 μM) compared to naked agent against MiaPaCa-2 pancreatic carcinoma cells. Selectivity for cancer cells was confirmed by comparing their activity to non-tumourigenic human fibroblasts (GI₅₀ > 200 μM). Transferrin receptor (TfR-1) expression, detected only in lysates prepared from carcinoma cells, may contribute to the cancer-selectivity. The G₁ cell cycle arrest caused by AFt-Neq0554 resulting in cytostasis was corroborated by clonogenic assays. Superior and more persistent inhibition of cathepsin L up to 80% was achieved with AFt-encapsulated agent in HCT-116 cells following 6 h exposure to 50 μM agent. The selective anticancer activity of AFt-encapsulated cysteine protease inhibitor Neq0554 reported here warrants further preclinical in vivo evaluation.

Novel apoferritin encapsulated cysteine protease inhibitors are developed with enhanced and selective uptake by cancer cells, and sustained pH-induced release of the agent. The persistent inhibition of cathepsin L is demonstrated in vitro.