Magnetic-Driven Hydrogel Microrobots Selectively Enhance Synthetic Lethality in MTAP-Deleted Osteosarcoma

Abstract

Background: Drugs based on synthetic lethality have advantages such as inhibiting tumor growth and affecting normal tissue in vivo. However, specific targets for osteosarcoma have not been acknowledged yet. In this study, a non-targeted but controllable drug delivery system has been applied to selectively enhance synthetic lethality in osteosarcoma in vitro, using the magnetic-driven hydrogel microrobots. Methods: In this study, EPZ015666, a PRMT5 inhibitor, was selected as the synthetic lethality drug. Then, the drug was carried by hydrogel microrobots containing Fe₃O₄. Morphological characteristics of the microrobots were detected using electron microscopy. In vitro drug effect was detected by the CCK-8 assay kit, Western blotting, etc. Swimming of microrobots was observed by a timing microscope. Selective inhibition was verified by cultured tumors in an increasing magnetic field. Results: Genomic mutation of MTAP deletion occurred commonly in pan-cancer in the TCGA database (nearly 10.00%) and in osteosarcoma in the TARGET database (23.86%). HOS and its derivatives, 143B and HOS/MNNG, were detected by MTAP deletion according to the CCLE database and RT-PCR. EPZ015666, the PRMT5 inhibitor, could reduce the SDMA modification and inhibition of tumor growth of 143B and HOS/MNNG. The hydrogel microrobot drug delivery system was synthesized, and the drug was stained by rhodamine. The microrobots were powered actively by a magnetic field. A simulation of the selected inhibition of microrobots was performed and lower cell viability of tumor cells was detected by adding a high dose of microrobots. Conclusion: Our magnetic-driven drug delivery system could carry synthetic lethality drugs. Meanwhile, the selective inhibition of this system could be easily controlled by programming the strength of the magnetic field.

Keywords: MTAP deletion; PRMT5; drug delivery system; microrobots; osteosarcoma.

FIGURE 1

Frequent occurrence of the MTAP deletion in osteosarcoma. (A) Genomic mutation of MTAP in pan-cancer in the TCGA database. (B) Copy number of CDKN2A and MTAP in pan-cancer cell lines in the CCLE database. (C) Genomic mutation of MTAP in osteosarcoma in the TARGET database.

FIGURE 2

EPZ015666 inhibits the growth of MTAP-deleted osteosarcoma. (A) Relative abundance of MTAP RNA expression in hMSCs and common osteosarcoma cell lines (U2OS, SJSA-1, HOS, 143B and HOS/MNNG) in vitro, respectively. (B) Cell viability of MTAP-deleted osteosarcoma (black and red line represents 143B and HOS/MNNG, respectively) after using a concentration gradient of EZP015666 in vitro. (C) SDMA modification reduction by treated EPZ015666 (143B) in vitro. hMSC, human mesenchymal stem cell; IC50, half maximal inhibitory concentration; SDMA, symmetric di-methyl-arginine.

FIGURE 3

Synthesis and characterization of magnetic-driven hydrogel microrobots. (A) Schematic of the microrobot synthesis. (B) Microrobot characteristics under bright field. (C) Microrobot characteristics under dark field and the EPZ015666 stained by rhodamine was detected as red fluorescence. (D,E) By enhancing the intensity and frequency of the magnetic field, the velocity of microrobots was growing faster. Scale bar of B,C, and E = 50 μm.

FIGURE 4

Predetermined locomotion of magnetic-driven hydrogel microrobots. (A) The microrobot was driven by the predetermined direction of a square. (B) The microrobot was driven by the predetermined direction of letter H.

FIGURE 5

The simulation of selectively drug inhibition of microrobots in vitro. (A) The sketch map of simulation. Most of the microrobots were driven by the magnetic field to one side of the culture dish and then the liquid was added to both sides (low-dose and high dose sides of microrobots) in the 96-well plate culturing HOS/MNNG tumor cells. (B) A lower cell viability was detected in the high dose of microrobots (**: p < 0.01). L, Low-dose; H, High-dose; D + M, Microrobots with EPZ015666; D, Dissociative EPZ015666; M, Drug-free microrobots.