Anionic clay as the drug delivery vehicle: tumor targeting function of layered double hydroxide-methotrexate nanohybrid in C33A orthotopic cervical cancer model

Abstract

Methotrexate (MTX), an anticancer agent, was successfully intercalated into the anionic clay, layered double hydroxides to form a new nanohybrid drug. The coprecipitation and subsequent hydrothermal method were used to prepare chemically, structurally, and morphologically well-defined two-dimensional drug-clay nanohybrid. The resulting two-dimensional drug-clay nanohybrid showed excellent colloidal stability not only in deionized water but also in an electrolyte solution of Dulbecco’s Modified Eagle’s Medium with 10% fetal bovine serum, in which the average particle size in colloid and the polydispersity index were determined to be around 100 and 0.250 nm, respectively. The targeting property of the nanohybrid drug was confirmed by evaluating the tumor-to-blood and tumor-to-liver ratios of the MTX with anionic clay carrier, and these ratios were compared to those of free MTX in the C33A orthotopic cervical cancer model. The biodistribution studies indicated that the mice treated with the former showed 3.5-fold higher tumor-to-liver ratio and fivefold higher tumor-to-blood ratio of MTX than those treated with the latter at 30 minutes postinjection.

Keywords:

• anionic clay
• biodistribution
• cervical cancer
• colloidal stability
• layered double hydroxide
• methotrexate

Supplementary materials

Figure S1 (A) Molecular structure of methotrexate (MTX; (2S)-2-[(4-{[(2,4-diamino-7,8-dihydropteridin-6-yl)methyl](methyl)amino}phenyl)formamido]pentanedioic acid), and (B) plots of MTX molar fractions vs pH (pK_a1 =3.8, pK_a2=4.8).¹

Figure S2 Scanning electron microscopic images of (A) pristine LDH, and (B) LDH-MTX nanohybrid in distilled water, respectively. The inset images (A and B) correspond to the enlarged images for pristine LDH and LDH-MTX, respectively.

Abbreviations: LDH, layered double hydroxide; LDH-MTX, layered double hydroxide-methotrexate.

Figure S3 The particle size distribution and the high-resolution transmission electron microscopy images of (A and B) pristine LDH, and (C and D) LDH-MTX in distilled water, respectively. The inset images (B and D) correspond to the enlarged images for pristine LDH and LDH-MTX, respectively.

Abbreviations: LDH, layered double hydroxide; LDH-MTX, layered double hydroxide-methotrexate.

Figure S4 Digital images of tumor tissue in mice treated with PBS, LDH, MTX, and LDH-MTX. PBS, LDH, MTX, and LDH-MTX were administered via intraperitoneal injection on days 0, 7, 14, 21, and 28, and tumor tissues were collected on 32 days.

Abbreviations: LDH, layered double hydroxide; MTX, methotrexate; LDH-MTX, layered double hydroxide-methotrexate; PBS, phosphate-buffered saline.

Figure S5 Immune response of MTX and LDH-MTX nanohybrids on the production of proinflammatory cytokine, (A) TNF-α and (B) IL-6.

Abbreviations: h, hours; IL-6, interleukin-6; MTX, methotrexate; LDH-MTX, layered double hydroxide-methotrexate; PBS, phosphate-buffered saline; TNF-α, tumor necrosis factor-α.

Table S1 Tumor-to-liver and tumor-to-blood ratio of MTX in MTX-treated group and LDH-MTX-treated one

Acknowledgments

This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (2005-0049412). G Choi is thankful to the Solvay Scholarship.

Disclosure

The authors report no conflicts of interest in this work.