New Derivatives of N- Hydroxybutanamide: Preparation, MMP Inhibition, Cytotoxicity, and Antitumor Activity

Abstract

Using a novel method of N-substituted succinimide ring opening, new N-hydroxybutanamide derivatives were synthesized. These compounds were evaluated for their ability to inhibit matrix metalloproteinases (MMPs) and their cytotoxicity. The iodoaniline derivative of N¹-hydroxy-N⁴-phenylbutanediamide showed the inhibition of MMP-2, MMP-9, and MMP-14 with an IC₅₀ of 1-1.5 μM. All the compounds exhibited low toxicity towards carcinoma cell lines HeLa and HepG2. The iodoaniline derivative was also slightly toxic to glioma cell lines A-172 and U-251 MG. Non-cancerous FetMSC and Vero cells were found to be the least sensitive to all the compounds. In vivo studies demonstrated that the iodoaniline derivative of N¹-hydroxy-N⁴-phenylbutanediamide had low acute toxicity. In a mouse model of B16 melanoma, this compound showed both antitumor and antimetastatic effects, with a 61.5% inhibition of tumor growth and an 88.6% inhibition of metastasis. Our findings suggest that the iodoaniline derivative of N¹-hydroxy-N⁴-phenylbutanediamide has potential as a lead structure for the development of new MMP inhibitors. Our new synthetic approach can be a cost-effective method for the synthesis of inhibitors of metalloenzymes with promising antitumor potential.

Keywords: N-hydroxybutanamides; N-substituted succinimide ring opening method; acute toxicity; antimetastatic activity; antitumor activity; cytotoxicity; hydroxamic acids; matrix metalloproteinases.

Figure 1

Basic approaches to the synthesis of hydroxamic acids. (i) Synthesis of HAs from carboxylic acids using their activated forms. (ii) Synthesis of HAs from esters. (iii) Synthesis of HAs from N-acyloxazolidinones in the presence of samarium triflate. (iv) Synthesis of HAs from amides in the presence of Pseudomonas aeruginosa or Bacillus smithii. (v) The conversion of aldehydes in the presence of sodium hyponitrite or N-hydroxy succinimide and cobalt diacetate. (vi) Solid-phase synthesis of HAs.

Figure 2

Well-known MMP inhibitors containing a N-hydroxybutanamide fragment (highlighted in blue).

Scheme 1

Synthesis of N-hydroxybutanamide derivatives.

Figure 3

Activity of (a) MMP-2; (b) MMP-3; (c) MMP-9; (d) MMP-14 in the presence of 1–5 or NNGH at a concentration of 1 μM. Significant differences are shown as *** p < 0.001 vs. control and as # p < 0.001 vs. NNGH.

Figure 4

Dose–response curves for MMPs in the presence of 4.

Figure 5

Docked poses of 1 (a) and 4 (b) at the active site of MMP-9. Complexes are represented in ball and stick style. The S1′ pocket is highlighted in green, and the zinc atom is highlighted in pink.

Figure 5

Docked poses of 1 (a) and 4 (b) at the active site of MMP-9. Complexes are represented in ball and stick style. The S1′ pocket is highlighted in green, and the zinc atom is highlighted in pink.

Figure 6

Dose–effect relationships for 1–5 after 72 h of exposure in cells (a) A-172; (b) U-251 MG; (c) HeLa; (d) HepG2; (e) FetMSC; and (f) Vero.

Figure 6

Dose–effect relationships for 1–5 after 72 h of exposure in cells (a) A-172; (b) U-251 MG; (c) HeLa; (d) HepG2; (e) FetMSC; and (f) Vero.

Figure 7

Relative body weight changes in groups of mice that received different single doses of 4, with 100% representing the body weight at the beginning of the experiment.

Figure 8

Effect of 4 on the growth of syngeneic B16 melanoma. Tumor growth was measured with a caliper, and the mean ± SE was plotted for n = 7 in each treatment group.