ERK-Peptide-Inhibitor-Modified Ferritin Enhanced the Therapeutic Effects of Paclitaxel in Cancer Cells and Spheroids

Abstract

Rational design of a drug delivery system with enhanced therapeutic potency is critical for efficient tumor chemotherapy. Many protein-based drug delivery platforms have been designed to deliver drugs to target sites and improve the therapeutic efficacy. In this study, paclitaxel (PTX) molecules were encapsulated within an apoferritin nanocage-based drug delivery system with the modification of an extracellular-signal-regulated kinase (ERK) peptide inhibitor at the C-terminus of ferritin (HERK). Apoferritin is an endogenous nano-sized spherical protein which has the ability to specially bind to a majority of tumor cells via interacting with transferrin receptor 1. The ERK peptide inhibitor is a peptide which can disrupt the interaction of MEK with ERK in the mitogen-activated protein kinase/ERK pathway. By combining the targeted delivery effect of ferritin and the inhibitory effect of the ERK peptide inhibitor, the newly fabricated ferritin carrier nanoparticle HERK could still be taken up by tumor cells, and it displayed higher cell cytotoxicity than the parent ferritin. After loading with PTX, HERK-PTX displayed a favorable anticancer effect in human breast cancer cells MDA-MB-231 and lung carcinoma cells A549. The remarkable inhibitory effect on MDA-MB-231 tumor spheroids was also identified. These results indicated that the constructed HERK nanocarrier is a promising multi-functional drug delivery vehicle to enhance the therapeutic effect of drugs in cancer therapy.

Targeting Extracellular Signal-Regulated Protein Kinase 1/2 (ERK1/2) in Cancer: An Update on Pharmacological Small-Molecule Inhibitors

“…More importantly, ulixertinib, as the most popular inhibitor of ERK1/2 in clinical trials, has achieved remarkable therapeutic effects in human cancers, especially in patients with RAS , RAF , and MEK mutations, which is close to becoming an officially approved cancer drug. Moreover, modification of the C-terminus of a targeted delivery ferritin vector with an ERK peptide inhibitor has been reported to suppress tumor proliferation, induce cell cycle arrest at the G2/M phase in MDA-MB-231 human breast cancer cells and A549 human lung adenocarcinoma cells, and effectively inhibit the growth of MDA-MB-231 tumor spheroids, which can greatly enhance the therapeutic effect of paclitaxel . In KRAS mutant PDAC, autophagy promotes tumor growth, synergistically inhibiting insulin-like growth factor 1 receptor (IGF1R), and ERK1/2 increases the sensitivity to autophagic inhibitors .…”

“…Moreover, modification of the C-terminus of a targeted delivery ferritin vector with an ERK peptide inhibitor has been reported to suppress tumor proliferation, induce cell cycle arrest at the G2/M phase in MDA-MB-231 human breast cancer cells and A549 human lung adenocarcinoma cells, and effectively inhibit the growth of MDA-MB-231 tumor spheroids, which can greatly enhance the therapeutic effect of paclitaxel. 75 In KRAS mutant PDAC, autophagy promotes tumor growth, synergistically inhibiting insulin-like growth factor 1 receptor (IGF1R), and ERK1/2 increases the sensitivity to autophagic inhibitors. 76 Interestingly, intermittent fasting, a potentially promising dietary intervention strategy in cancer therapy, combined with ERK1/2 inhibition can effectively enhance the efficacy of chemotherapy.…”

Effective Delivery of Paclitaxel-Loaded Ferritin via Inverso CendR Peptide for Enhanced Cancer Therapy

“…To release PTX from ferritin-PTX complex (1 mL), 0.1 M HCl was added to adjust the pH to 2.0, and another 1 mL of ethanol was added for extraction. PTX concentration was quantitatively determined by high-performance liquid chromatography (HPLC) (Agilent 1260, USA) at 227 nm according to established method . The concentration of protein was determined using BCA method.…”

“…H L (RGE), H D (RPPR), and H D (RGE) NPs were labeled by FITC as previously reported . A549 and MCF-7 cells were seeded onto glass coverslips in a 24-well plate at a density of 3 ×10 4 cells/well.…”

“…Tumor spheroids were prepared to further evaluate the tumor penetration ability of the peptide-modified ferritins. , Briefly, A549 cells (8 × 10 3 cells per well) were seeded in 96-well plates that had been pre-coated with 80 μL of 2% low-melting-temperature agarose to prepare tumor spheroids. Free FITC and FITC-labeled ferritins (FITC at a concentration of 10 μg/mL) were added into wells after the cells had grown for 5 days and then incubated for 4 h. After washing and fixing the spheroids for 30 min, they were then observed using CLSM.…”