J Appl Biomed 14:229-234, 2016 | DOI: 10.1016/j.jab.2016.03.002

Antitumoral activity of novel 1,4-naphthoquinone derivative involves L-type calcium channel activation in human colorectal cancer cell line

Juan Carlos Ramos Gonçalves^a,b,*, Tangbadioa Herve Coulidiati^a, André Luís Monteiro^a, Laís Campos Teixeira de Carvalho-Gonçalves^a, Wagner de Oliveira Valença^c, Ronaldo Nascimento de Oliveira^c, Celso de Amorim Câmara^c, Demetrius Antônio Machado de Araújo^a

^a Department of Biotechnology, Federal University of Paraiba, João Pessoa, Brazil

^b Department of Biochemistry and Pharmacology, Federal University of Piauí, Teresina, Brazil

^c Department of Molecular Sciences, Rural Federal University of Pernambuco, Recife, Brazil

Colorectal cancer (CRC) is an important public health problem estimated as the third most commonly diagnosed cancer worldwide. Naphthoquinones are compounds present in different families of plants and interesting for medicinal chemistry due to their activities as potent inhibitors of human cancer growth. In this way, our study aimed to evaluate the cytotoxicity and selectiveness of four 2,3-triazole-1,4-naphthoquinone derivatives (N1-N4) towards the CRC cell line HT-29 and normal human cells. MTT assay showed that N1, N2, N3 and N4 elicited distinct cytotoxic potency, exhibiting EC₅₀ values of 40.6 ± 1.0, 100.1 ± 1.0, 241.9 ± 1.2 and 101.9 ± 1.1, respectively. Later, flow cytometry in HT-29 cells loaded with propidium iodide (5 μM), indicated the ability of N4 (0.5-50 μM) to induce cell membrane damage. Additionally, calcium imaging experiments were conducted in HT-29 cells loaded with 5 μM Fluo-3/AM to assess intracellular Ca²⁺ (iCa²⁺). Our data demonstrated that N4 induces a fast and strong increase of iCa²⁺ in HT-29 cells, mediated by voltage-gated L-type Ca²⁺ channels activation. In conclusion, our study reported on the cytotoxicity and selectiveness of 1,2,3-triazol substituted 1,4-naphthoquinones towards the HT-29 CRC cell line. Furthermore, we have demonstrated the participation of voltage-gated L-type Ca²⁺ channels in the N4 mechanism.

Keywords: Natural products; Pharmacology; Cytotoxicity; Ion channels; HT-29; Flow cytometry; Calcium imaging

Received: January 14, 2016; Revised: March 9, 2016; Accepted: March 23, 2016; Published: August 1, 2016  Show citation