Selection and Characterization of a Peptide Specifically Targeting to Gastric Cancer Cell Line SGC-7901 Using Phage Display

The APEX1/miRNA-27a-5p axis plays key roles in progression, metastasis and targeted chemotherapy of gastric cancer

Gastric cancer (GC) presents a challenge for conventional therapeutics due to low targeting specificity and subsequent elicitation of multiple drug resistance (MDR). As an essential enzyme for DNA repair, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) exhibits multiple functions to affect cancer malignancy and is excessively expressed in GC. However, the roles APEX1 and its inhibitor miR-27a-5p play in modulating GC progression and MDR development remains unclear. Here, we verified APEX1 as a target of miR-27a-5p and subsequently established the APEX1-deleted SGC-7901 cell line by CRISPR/Cas9 editing. The roles of the APEX1/miR-27a-5p axis in GC progression, metastasis and doxorubicin (DOX) resistance were explored by the targeted chemotherapy facilitated by a GC-specific peptide (GP5) functionalized liposomal drug delivery formulation (GP5/Lipo/DOX/miR-27a-5p). The results showed that APEX1 deletion distinctly attenuated cell growth and metastatic properties in GC, and also sensitized GC cells to DOX. Notably, miR-27a-5p was validated as a suppressor of APEX1-dependent GC development and DOX resistance by a RAS/MEK/FOS and PTEN/AKT/SMAD2 pathway-dependent manner. The altered expression of epithelial-mesenchymal transition (EMT) signatures and signal pathway proteins in the APEX1-deleted cells implied that APEX1 potentially enhances DOX resistance of GC cells by altering the regulation of MAPK and AKT pathways, leading to compromised efficacy of chemotherapy or by initiating additional DNA damage response pathways. Taken together, these findings revealed that as a novel therapeutic target, APEX1/miR-27a-5p axis plays essential roles in modulating the GC development and MDR, and the GC targeted drug delivery formulation presents a strategic reference for the future designation of chemotherapeutics study.

Molecular targeted treatment and drug delivery system for gastric cancer

Gastric cancer is still a major cancer worldwide. The early diagnosis rate of gastric cancer in most high incidence countries is low. At present, the overall treatment effect of gastric cancer is poor, and the median overall survival remains low. Most of the patients with gastric cancer are in an advanced stage when diagnosed, and drug treatment has become the main means. Thus, new targeted drugs and therapeutic strategies are the hope of improving the therapeutic effect of gastric cancer. In this review, we summarize the new methods and advances of targeted therapy for gastric cancer, including novel molecular targeted therapeutic agents and drug delivery systems, with a major focus on the development of drug delivery systems (drug carriers and targeting peptides). Elaborating these new methods and advances will contribute to the management of gastric cancer.

Data on the sequence-derived properties of gastric cancer - binding peptides

The article presents a dataset containing nine classes of calculated sequence-derived descriptors for 78 peptide sequences, 21 of which demonstrate the ability to bind with gastric cancer cells. The datasaet was used in the paper "A screening algorithm for gastric cancer binding peptides" [1] for the creation of a classification model that can predict the ability of a given peptide sequence to bind with gastric cancer cells. The 78 peptide sequences were extracted from a systematic literature search, and the various peptide descriptors were calculated using the R package "Peptides". The nine calculated sequence-derived descriptor classes are the Blosum indices, Cruciani properties, FASGAI vectors, Kidera factors, ProtFP, ST-scales, T-scales, VHSE scales, and Z-scales. The resulting dataset, which is composed of over 4000 data points, offers a rich resource for further protochemometric analyses of the curated peptide sequences relevant to cancer diagnostics and therapeutics.

Phage nanofibers in nanomedicine: Biopanning for early diagnosis, targeted therapy, and proteomics analysis

Display of a peptide or protein of interest on the filamentous phage (also known as bacteriophage), a biological nanofiber, has opened a new route for disease diagnosis and therapy as well as proteomics. Earlier phage display was widely used in protein-protein or antigen-antibody studies. In recent years, its application in nanomedicine is becoming increasingly popular and encouraging. We aim to review the current status in this research direction. For better understanding, we start with a brief introduction of basic biology and structure of the filamentous phage. We present the principle of phage display and library construction method on the basis of the filamentous phage. We summarize the use of the phage displayed peptide library for selecting peptides with high affinity against cells or tissues. We then review the recent applications of the selected cell or tissue targeting peptides in developing new targeting probes and therapeutics to advance the early diagnosis and targeted therapy of different diseases in nanomedicine. We also discuss the integration of antibody phage display and modern proteomics in discovering new biomarkers or target proteins for disease diagnosis and therapy. Finally, we propose an outlook for further advancing the potential impact of phage display on future nanomedicine. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

The further characterization of the peptide specifically binding to gastric cancer

Targeting peptide has been considered to be useful as a small molecule probe leading to multifunctional properties for both imaging detection and targeting therapy. Thus, the identification of novel targets is urgently needed to develop innovative agents to effectively control gastric cancer metastasis and progression. Previously, we reported a novel 12-mer peptide, GP-5 (IHKDKNAPSLVP), binding to gastric carcinoma (GC) cells specifically and sensitively, and it was screened by using a phage displayed peptide library and primarily analyzed. In this study, it was further identified via fluorescence microscopy, flow cytometry, tissue chip and other methods. Our results indicated that the peptide GP-5 presents a particularly high affinity and specificity to GC cells and tissues, whereas only background detection occurred with other control cancer cells, cancer tissues or normal tissues. Taken together, all results support that the peptide GP-5 is a potential candidate to be developed as a useful molecule fragment for the imaging detection and targeting therapy of GC.