CIP-13F, a novel aminopeptidase N (APN/CD13) inhibitor, inhibits Lewis lung carcinoma growth and metastasis in mice

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

A modified DAW-22 compound F-B1 inhibits Bcr/Abl and induces apoptosis in chronic myelogenous leukemia cells

The Bcr/Abl kinase is an oncogenic fusion protein that plays a central role in the pathogenesis of chronic myeloid leukemia (CML). Some small-molecule kinase inhibitors such as imatinib were developed in the treatment of CML; however, resistant to imatinib is an emerging problem of CML therapy. Hence, additional approaches or compounds targeting leukemogenic cells are required. F-B1 is a new compound obtained by modifying DAW-22, a natural sesquiterpenoid coumarin, which was isolated from traditional Chinese medicine Ferula ferulaeoides (Steud.) Korov. F-B1 was found to inhibit the growth of myelogenous leukemia cell lines, that is, K562 cells bearing wild-type Bcr/Abl and imatinib-resistant K562G cells. F-B1 potently down-regulated the mRNA and protein levels of Bcr/Abl, followed by suppression of the downstream molecules such as Akt, externally regulated kinases, and nuclear factor κB. In addition, F-B1 also induced cell apoptosis by impairing the balance between proapoptotic protein Bax and antiapoptotic proteins Bcl-2 and Bcl-XL and increased the activity of mitochondrial-dependent apoptosis in nude mouse xenografts. Experimental validation results together demonstrated that F-B1 can inhibit Bcr/Abl fusion proteins in K562 and K562G cells, implying that F-B1 might be a promising drug to treat CML, especially the imatinib-resistant CML.

13F-1, a novel 5-fluorouracil prodrug containing an Asn-Gly-Arg (NO2) COOCH3 tripeptide, inhibits human colonic carcinoma growth by targeting Aminopeptidase N (APN/CD13)

13F-1 is a 5-fluorouracil prodrug containing an Asn-Gly-Arg (NO2) COOCH3 tripeptide. 13F-1 might possess the activity against cancer growth by targeting Aminopeptidase N (APN/CD13). Our goal in this study was to evaluate the inhibitory effect of 13F-1 on the growth of human colonic carcinoma by both in vitro and in vivo studies. Experiments were performed in colonic carcinoma Colo205 cells, which highly express APN/CD13 on cell surface. The inhibition of 13F-1 on cancer cell growth was estimated by the colorimetric and clonogenic assays. The assays of Annexin V-FITC/PI and JC-1 fluorescence probe were employed to determine the apoptotic cells. Further experiment was performed in mice bearing Colo205 xenografts. 13F-1 was injected for three consecutive weeks. The specimens of Colo205 xenografts were removed for TUNEL staining and western blotting analysis. The expressions of APN/CD13 were analyzed by immunofluorescent flow cytometry and western blotting assays. 13F-1 significantly inhibited Colo205 cell proliferation. 13F-1 by injection delayed the expansion of Colo205 xenografts without significant toxicity to mice. The inhibitory effect of 13F-1 might arise from its role in apoptotic induction. Further analysis indicated that 13F-1 strongly inhibited APN/CD13 expression on cancer cell surface. In contrast, 5-FU did not affect APN/CD13 expression. These results indicated the mechanism of 13F-1 action that 13F-1׳s effect was associated with its role in suppression of APN/CD13 expression. Conclusion, 13F-1 could be developed as a promising agent for treatment of cancers with high expression of APN/CD13.

Positioning of aminopeptidase inhibitors in next generation cancer therapy

Aminopeptidases represent a class of (zinc) metalloenzymes that catalyze the cleavage of amino acids nearby the N-terminus of polypeptides, resulting in hydrolysis of peptide bonds. Aminopeptidases operate downstream of the ubiquitin-proteasome pathway and are implicated in the final step of intracellular protein degradation either by trimming proteasome-generated peptides for antigen presentation or full hydrolysis into free amino acids for recycling in renewed protein synthesis. This review focuses on the function and subcellular location of five key aminopeptidases (aminopeptidase N, leucine aminopeptidase, puromycin-sensitive aminopeptidase, leukotriene A4 hydrolase and endoplasmic reticulum aminopeptidase 1/2) and their association with different diseases, in particular cancer and their current position as target for therapeutic intervention by aminopeptidase inhibitors. Historically, bestatin was the first prototypical aminopeptidase inhibitor that entered the clinic 35 years ago and is still used for the treatment of lung cancer. More recently, new generation aminopeptidase inhibitors became available, including the aminopeptidase inhibitor prodrug tosedostat, which is currently tested in phase II clinical trials for acute myeloid leukemia. Beyond bestatin and tosedostat, medicinal chemistry has emerged with additional series of potential aminopeptidases inhibitors which are still in an early phase of (pre)clinical investigations. The expanded knowledge of the unique mechanism of action of aminopeptidases has revived interest in aminopeptidase inhibitors for drug combination regimens in anti-cancer treatment. In this context, this review will discuss relevant features and mechanisms of action of aminopeptidases and will also elaborate on factors contributing to aminopeptidase inhibitor efficacy and/or loss of efficacy due to drug resistance-related phenomena. Together, a growing body of data point to aminopeptidase inhibitors as attractive tools for combination chemotherapy, hence their implementation may be a step forward in a new era of personalized treatment of cancer patients.

Oldhamianoside II, a new triterpenoid saponin, prevents tumor growth via inducing cell apoptosis and inhibiting angiogenesis

Oldhamianoside II is a new triterpenoid saponin that was isolated from the roots of Gypsophila oldhamiana. The present study aims to investigate the potential inhibitory activity of oldhamianoside II on tumor growth using an S180 tumor implantation mouse model. Oldhamianoside II at doses of 5.0 and 10.0 mg/kg was given with intraperitoneal injection for 10 days following subcutaneous inoculation of S180 tumor cells in anterior flank of mice. The tumor growth, the cell apoptosis, the microvessel density (MVD) in S180 tumors, the tumor cell viability, the tubular formation in vitro, and migration of tumor cells were examined. The expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and cyclooxygenase-2 (COX-2) was determined to analyze the associated mechanisms. The results showed that oldhamianoside II potently inhibited tumor cell viability in vitro. In addition, oldhamianoside II delayed tumor growth in anterior flank, induced S180 cell apoptosis, and reduced the MVD. Oldhamianoside II was also demonstrated to decrease the number of tubular structure and vessel formation in HUVEC cultures and chick embryo chorioallantoic membrane (CAM) model, respectively. Further study indicated that oldhamianoside II reduced the expression of VEGF, bFGF, and COX-2 in tumor sections. Moreover, oldhamianoside II inhibited the activity of migration and penetration to Matrigel of SGC7901 tumor cells in scratch wound and transwell chamber. In conclusion, our work defines oldhamianoside II, a new triterpenoid saponin, as a novel compound that can effectively inhibit S180 tumor growth, induce tumor cell apoptosis, prevent tumor angiogenesis, and inhibit cancer cell migration, suggesting that oldhamianoside II is a potential drug candidate for the treatment of cancer and for the prevention of metastasis.

Comparative proteomic and phosphoproteomic profiling of pancreatic adenocarcinoma cells treated with CB1 or CB2 agonists

The pancreatic adenocarcinoma cell line Panc1 was treated with cannabinoid receptor ligands (arachidonylcyclopropylamide or GW405833) in order to elucidate the molecular mechanism of their anticancer effect. A proteomic approach was used to analyze the protein and phosphoprotein profiles. Western blot and functional data mining were also employed in order to validate results, classify proteins, and explore their potential relationships. We demonstrated that the two cannabinoids act through a widely common mechanism involving up- and down-regulation of proteins related to energetic metabolism and cell growth regulation. Overall, the results reported might contribute to the development of a therapy based on cannabinoids for pancreatic adenocarcinoma.