RESUMO
Multidrug resistance (MDR) is the main factor of tumor recurrence and chemotherapy failure in clinical practice. Its mechanism is relatively complex, and one of the most thoroughly studied mechanism is the overexpression of P-glycoprotein (P-gp) on tumor cell membrane. Most of the chemotherapy drugs are p-gp substrates, and tumor cells will transport the chemotherapy drugs to the extracellular through p-gp mediated active transport, so that the concentration of effective drugs in the cell is reduced, resulting in drug resistance, leading to the decline of clinical efficacy. The reversal agent of P-gp can reduce the intracellular pumping of chemotherapeutic drugs by regulating the expression and transport activity of P-gp, and enhance the sensitivity of tumor cells to chemotherapeutic drugs, thus improving the therapeutic effect. In this paper, we will summarize the natural plant active ingredients that can reverse P-gp mediated MDR to provide reference for clinical and related studies.
RESUMO
To prepare peptide-modified chitosan tetramethylprazine nanoparticles(FGF-CS-TMP-NPS) and investigate its reversal effect on multidrug resistance in tumor cells. The pEGF-CS-TMP-NPs were prepared by ion crosslinking method, and their physicochemical properties were investigated. Western blot was used to detect the expression levels of epidermal growth factor receptor(EGFR)(MCF-7, MCF-7/ADR, K562 and K562/ADR) and drug-resistant related protein P-gp. MCF-7/ADR and K562/ADR were selected as cell models. The cytotoxicity of pEGF-CS-TMP-NPs, the multiple of cell resistance to adriamycin, the reversal resistance index of pEGF-CS-TMP-NPs to doxorubicin and the sensitization of pEGF-CS-TMP-NPs to doxorubicin were detected by MTT assay. After MCF-7/ADR and K562/ADR were treated with pEGF-CS-TMP-NPs, the expression changes of P-gp were detected by Western blot. The encapsulation efficiency and drug loading of pEGF-CS-TMP-NPs were 37.66%± 0.53% and 3.25%± 0.34% respectively in HPLC. The nanoparticles showed an average particle size of(150.50±9.3) nm, polymer dispersity index of(0.059±0.007) and Zeta potential of(19.30±2.02) mV as detected by laser particle size analyzer. The nanoparticles were spherical and well dispersed under transmission electron microscope. Western blot results showed that EGFR was positively expressed in MCF-7 and MCF-7/ADR cells, while negatively expressed in K562 and K562/ADR cells. P-gp was highly expressed in MCF-7/ADR and K562/ADR, while negatively expressed in MCF-7 and K562. pEGF-CS-TMP-NPs had a weak effect on MCF-7/ADR and K562/ADR. The adriamycin resistance of MCF-7/ADR cells was 108.36 times, and that of K562/ADR cells was more than 100 times. When IC_(85) of pEGF-CS-TMP-NPs was used as the administration concentration, the reversion index of MCF-7/ADR and K562/ADR cells was 3.68 and 1.87, respectively. pEGF-CS-TMP-NPs could enhance the sensitivity of adriamycin to MCF-7/ADR cells in a positive correlation with the concentration, and the sensitivity was significantly higher than that of K562/ADR cells. Western blot results showed that the expression level of P-gp in MCF-7/ADR cells decreased significantly after treatment with pEGF-CS-TMP-NPs, while the expression level of P-gp in K562/ADR cells did not change significantly. Experimental results show that pEGF-CS-TMP-NPs have an active targeting effect on MCF-7/ADR cells with high EGFR expression, and can effectively reverse the multidrug resistance of MCF-7/ADR cells. Active targeting effect is related to the peptides modification of nanoparticles, and the mechanism of reversing tumor MDR may be achieved by down-regulating the expression level of P-gp.