Discovery of a Series of Theophylline Derivatives Containing 1,2,3-Triazole for Treatment of Non-Small Cell Lung Cancer

Abstract

Chemotherapy is the most common clinical treatment for non-small cell lung cancer (NSCLC), but low efficiency and high toxicity of current chemotherapy drugs limit their clinical application. Therefore, it is urgent to develop hypotoxic and efficient chemotherapy drugs. Theophylline, a natural compound, is safe and easy to get, and it can be used as a modified scaffold structure and hold huge potential for developing safe and efficient antitumor drugs. Herein, we linked theophylline with different azide compounds to synthesize a new type of 1,2,3-triazole ring-containing theophylline derivatives. We found that some theophylline1,2,3-triazole compounds showed a good tumor-suppressive efficacy. Especially, derivative d17 showed strong antiproliferative activity against a variety of cancer cells in vitro, including H460, A549, A2780, LOVO, MB-231, MCF-7, OVCAR3, SW480, and PC-9. It is worth noting that the two NSCLC cell lines H460 H and A549 are sensitive to compound d17 particularly, with IC50 of 5.929 ± 0.97 μM and 6.76 ± 0.25 μM, respectively. Compound d17 can significantly induce cell apoptosis by increasing the ratio of apoptotic protein Bax/Bcl-2 by downregulating the expression of phosphorylated Akt protein, and it has little toxicity to normal hepatocyte cells LO2 at therapeutic concentrations. These data indicate that these theophylline acetic acid-1,2,3-triazole derivatives may be potential drug candidates for anti-NSCLC and are worthy of further study.

Keywords: 1,2,3-triazole; NSCLC; antitumor; apoptosis; theophylline.

FIGURE 1

Examples of the methylxanthine-containing compounds and the reported 1, 2, 3-triazole derivatives for treating tumors.

SCHEME 1

Reagents and conditions: (A) Theophylline acetic acid, 4-aminophenylacetylene, AHTU, and DIPEA were stirred in the DMF solvent 24 h at room temperature; (B) click reaction of copper sulfate water and sodium ascorbate in a solvent (tert-butanol: tetrahydrofuran: water = 1:1:1 at 85°C).

FIGURE 2

Compound d17 supresses H460 and A549 cancer cells. H460 (A), A549 (B), and LO2 (C) cells were exposed to compound d17 with indicated concentrations for 72 h, and cell viability was assessed by the CCK-8 assay, n = 3. *p-value < 0.05, **p-value < 0.01, and ***p-value < 0.001 (one-way ANOVA, followed by Tukey’s post-test).

FIGURE 3

Compound d17 suppresses H460 and A549 cancer cells. Fluorescence images of (A) H460 and (B) A549 cells exposed to compound d17 with indicated concentrations for 48 h and then stained with the red/green kit; green indicates live cells, and red indicates dead cells.

FIGURE 4

Compound d17 induced apoptosis of H460 and A549. Flow cytometry analysis data from three independent experiments were summarized and shown. NC, negative control. *p-value < 0.05, **p-value < 0.01, and ***p-value < 0.001 (one-way ANOVA, followed by Tukey’s post-test).

FIGURE 5

Compound d17 suppressed Akt phosphorylation and its transduction of downstream signaling Bax and Bcl-2 in NSCLC cells. Western blot was used to detect apoptosis-related markers Bax, Bcl-2 (A), and Akt (B). Protein bands (left images) and quantification (right images and tables below) are presented. NC, negative control. *p-value < 0.05, **p-value < 0.01, and ***p-value < 0.001 (one-way ANOVA, followed by Tukey’s post-test).