RGD4C peptide mediates anti-p21Ras scFv entry into tumor cells and produces an inhibitory effect on the human colon cancer cell line SW480

RGD-p21Ras-scFv expressed prokaryotically on a pilot scale inhibits ras-driven colorectal cancer growth by blocking p21Ras-GTP

BACKGROUND

Ras gene mutation and/or overexpression are drivers in the progression of cancers, including colorectal cancer. Blocking the Ras signaling has become a significant strategy for cancer therapy. Previously, we constructed a recombinant scFv, RGD-p21Ras-scFv by linking RGD membrane-penetrating peptide gene with the anti-p21Ras scFv gene. Here, we expressed prokaryotically RGD-p21Ras-scFv on a pilot scale, then investigated the anti-tumor effect and the mechanism of blocking Ras signaling.

METHODS

The E. coli bacteria which could highly express RGD-p21Ras-scFv was screened and grown in 100 L fermentation tank to produce RGD-p21Ras-scFv on optimized induced expression conditions. The scFv was purified from E. coli bacteria using His Ni-NTA column. ELISA was adopted to test the immunoreactivity of RGD-p21Ras-scFv against p21Ras proteins, and the IC50 of RGD-p21Ras-scFv was analyzed by CCK-8. Immunofluorescence colocalization and pull-down assays were used to determine the localization and binding between RGD-p21Ras-scFv and p21Ras. The interaction forces between RGD-p21Ras-scFv and p21Ras after binding were analyzed by molecular docking, and the stability after binding was determined by molecular dynamics simulations. p21Ras-GTP interaction was detected by Ras pull-down. Changes in the MEK-ERK /PI3K-AKT signaling paths downstream of Ras were detected by WB assays. The anti-tumor activity of RGD-p21Ras-scFv was investigated by nude mouse xenograft models.

RESULTS

The technique of RGD-p21Ras-scFv expression on a pilot scale was established. The wet weight of the harvested bacteria was 31.064 g/L, and 31.6 mg RGD-p21Ras-scFv was obtained from 1 L of bacterial medium. The purity of the recombinant antibody was above 85%, we found that the prepared on a pilot scale RGD-p21Ras-scFv could penetrate the cell membrane of colon cancer cells and bind to p21Ras, then led to reduce of p21Ras-GTP (active p21Ras). The phosphorylation of downstream effectors MEK-ERK /PI3K-AKT was downregulated. In vivo antitumor activity assays showed that the RGD-p21Ras-scFv inhibited the proliferation of colorectal cancer cell lines.

CONCLUSION

RGD-p21Ras-scFv prokaryotic expressed on pilot-scale could inhibited Ras-driven colorectal cancer growth by partially blocking p21Ras-GTP and might be able to be a hidden therapeutic antibody for treating RAS-driven tumors.

RGD peptide in cancer targeting: Benefits, challenges, solutions, and possible integrin-RGD interactions

RGD peptide can be found in cell adhesion and signaling proteins, such as fibronectin, vitronectin, and fibrinogen. RGD peptides' principal function is to facilitate cell adhesion by interacting with integrin receptors on the cell surface. They have been intensively researched for use in biotechnology and medicine, including incorporation into biomaterials, conjugation to medicinal molecules or nanoparticles, and labeling with imaging agents. RGD peptides can be utilized to specifically target cancer cells and the tumor vasculature by engaging with these integrins, improving drug delivery efficiency and minimizing adverse effects on healthy tissues. RGD-functionalized drug carriers are a viable option for cancer therapy as this focused approach has demonstrated promise in the future. Writing a review on the RGD peptide can significantly influence how drugs are developed in the future by improving our understanding of the peptide, finding knowledge gaps, fostering innovation, and making drug design easier.

Mechanisms of Action and Limitations of Monoclonal Antibodies and Single Chain Fragment Variable (scFv) in the Treatment of Cancer

Monoclonal antibodies are among the most effective tools for detecting tumor-associated antigens. The U.S. Food and Drug Administration (FDA) has approved more than 36 therapeutic antibodies for developing novel alternative therapies that have significant success rates in fighting cancer. However, some functional limitations have been described, such as their access to solid tumors and low interaction with the immune system. Single-chain variable fragments (scFv) are versatile and easy to produce, and being an attractive tool for use in immunotherapy models. The small size of scFv can be advantageous for treatment due to its short half-life and other characteristics related to the structural and functional aspects of the antibodies. Therefore, the main objective of this review was to describe the current situation regarding the mechanisms of action, applications, and limitations of monoclonal antibodies and scFv in the treatment of cancer.

ZNF24 regulates the progression of KRAS mutant lung adenocarcinoma by promoting SLC7A5 translation

Background

Clinical treatment of RAS mutant cancers is challenging because of the complexity of the Ras signaling pathway. SLC7A5 is a newly discovered downstream gene of the Ras signaling pathway, but the regulatory mechanism is unclear. We aimed to explore the molecular mechanism and role in KRAS mutant lung adenocarcinoma progression.

Methods

Key gene that regulated SLC7A5 in KRAS mutant lung adenocarcinoma was screened by RNA sequencing and bioinformatics analysis. The effect of this gene on the expression of SLC7A5 was studied by RNAi. The regulatory mechanism between the two genes was investigated by immunofluorescence, CoIP, pulldown and yeast two-hybrid assays. The location of the two genes was determined by inhibiting Ras and the downstream pathways PI3K-AKT and MEK-ERK. By in vivo and in vitro experiments, the effects of the key gene on the biological functions of KRAS mutant lung adenocarcinoma were explored.

Results

We found a novel gene, ZNF24, which upregulated SLC7A5 protein expression rather than mRNA expression in KRAS mutant lung adenocarcinoma. Endogenous protein interactions occurred between ZNF24 and SLC7A5. Ras inhibition reduced the expression of ZNF24 and SLC7A5. ZNF24 and SLC7A5 are located downstream of the MEK-ERK and PI3K-AKT pathways. In vivo and in vitro functional experiments confirmed that the ZNF24-SLC7A5 signaling axis promoted the proliferation, invasion and migration of KRAS mutant lung adenocarcinoma.

Conclusions

ZNF24 promoted the growth of KRAS mutant lung adenocarcinoma by upregulating SLC7A5 protein expression, which suggested that ZNF24 is a new biomarker of KRAS mutant tumors and could be a new potential therapeutic target for Ras-driven tumors.

Enhanced effect of autologous EVs delivering paclitaxel in pancreatic cancer

We engineered human pancreatic cancer cell (PANC-1)-derived extracellular vesicles (EVs) by conjugating the functional ligand RGD and magnetic nanoparticles (MNPs) onto EV surfaces (rmExo), for pancreatic cancer therapy. Paclitaxel (PTX) loaded into rmExo (rmExo-PTX) was intravenously injected into xenograft mice prepared using PANC-1 cells, which showed a significant reduction in tumor size compared to the free PTX-treated and control groups. The enhanced therapeutic effect was attributed to the modification of the surface of EVs using RGD, which has affinity for αvβ3 that is highly expressed in pancreatic cancer cells. Moreover, autologous EVs seemed to have more benefits in delivering PTX due to an unknown homing property to parent tumor cells, as exemplified by the reduced therapeutic effect of RGD-modified PANC-1 EVs on HT29 xenograft mice and RGD-modified U937 EVs on PANC-1 xenograft mice. The RGD-modified autologous EV vehicles were effective at penetrating and internalizing tumor cells, and eventually regressing the tumors, by mediating spontaneous removal of α-smooth muscle actin and collagen type 1 in the extracellular matrix of xenografts. Our results also identified an important molecule involved in the home-driving properties of PANC-1 EVs, integrin β3, which was expressed both on PANC-1 cells and the EVs derived from them. Additional therapeutic effect by permanent magnet near tumor xenograft was not observed in this study.

BR2 cell penetrating peptide effectively delivers anti-p21Ras scFv to tumor cells with ganglioside expression for therapy of ras-driven tumor

Purpose

Cell membrane penetrating peptide BR2 can bind with ganglioside and introduce foreign drugs into tumor cells. In this study, we employed BR2 to carry the broad-spectrum anti-p21Ras scFv prepared in our laboratory into ganglioside expressing tumor cells for therapy of ras-driven tumors.

Methods

BR2-p21Ras scFv gene was cloned to prokaryotic expression vector and expressed in E. coli BL21, then the fusion protein was purified with HisPur Ni-NTA. The immunoreactivity of the fusion protein with p21Ras was detected by ELISA and western blotting. The membrane-penetrating and immune co-localization with p21Ras of the fusion protein were determined by immunofluorescence. The antitumor activity was investigated using MTT, wound healing, colone formation, and apoptosis assays in vitro.

Results

BR2-p21Ras scFv fusion protein was successfully expressed and purified. We found that the fusion protein could specifically penetrate into human tumor cell lines which express ganglioside including human neuroblastoma cell line SK-N-SH, human colon cancer cell line HCT116 and human glioma cell line U251. After entering tumor cells the fusion protein bonded specifically with p21Ras. In vitro experiments revealed that it could significantly inhibit the proliferation, migration, and colone formation of HCT116, SK-N-SH, and U251 cells and promote the apoptosis of these tumor cells.

Conclusions

BR2-p21Ras scFv can penetrate ganglioside expressing tumor cells and inhibit the growth of ras-driven tumor by binding with p21Ras, and producing an inhibitory effect. It is suggested that BR2-p21Ras scFv is a potential ras-driven tumor therapeutic antibody.