The combination of thymoquinone and paclitaxel shows anti-tumor activity through the interplay with apoptosis network in triple-negative breast cancer

Abstract

Thymoquinone (TQ) is the active ingredient of Nigella sativa which has a therapeutic potential in cancer therapy and prevention. In this study, TQ has been shown to induce specific cytotoxicity and apoptosis and to inhibit wound healing in triple-negative breast cancer cell line. TQ also inhibited cancer growth in a mouse tumor model. Moreover, TQ and paclitaxel (Pac) combination inhibited cancer growth in cell culture and in mice. Genes involved in TQ and TQ-Pac-mediated cytotoxicity were studied using focused real-time PCR arrays. After bioinformatic analysis, genes in apoptosis, cytokine, and p53 signaling categories were found to be modulated with a high significance in TQ-treated cells (p < 10(-28), p < 10(-8), and p < 10(-6), respectively). Important to note, TQ has been found to regulate the genes involved in the induction of apoptosis through death receptors (p = 5.5 × 10(-5)). Additionally, tumor suppressor genes such as p21, Brca1, and Hic1 were highly upregulated by TQ and TQ-Pac combination. Interestingly, when cells were treated with high dose TQ, several growth factors such as Vegf and Egf were upregulated and several pro-apoptotic factors such as caspases were downregulated possibly pointing out key pathways manipulated by cancer cells to resist against TQ. In cells treated with the combination of TQ and Pac, genes in apoptosis cascade (p < 10(-12)), p53 signaling (p = 10(-5)), and JAK-STAT signaling (p < 10(-3)) were differentially expressed. TQ has also been shown to induce protein levels of cleaved Caspase-3, Caspase-7, and Caspase-12 and PARP and to reduce phosphorylated p65 and Akt1. The in vivo therapeutic potential of TQ-Pac combination and the genetic network involved in this synergy have been shown for the first time to the best of our knowledge.

Thymoquinone as a Potential Adjuvant Therapy for Cancer Treatment: Evidence from Preclinical Studies

“…In addition to the induction of synergistic cytotoxic effects through interference in tumor growth and survival signaling, combination treatment with TQ also exhibited chemo-protective effects and limited organ toxicity (Brown et al, 2014). Numerous other studies have investigated the potential chemo-potentiating effects of TQ with diverse classes of chemotherapeutic drugs (summarized in Table 1) including anti-estrogen (e.g., tamoxifen), topoisomerase-I inhibitor (e.g., topotecan), and microtubule disrupting agents (Rajput et al, 2013; Khalife et al, 2014, 2016; Dirican et al, 2015; Ganji-Harsini et al, 2016; Sakalar et al, 2016). Rajput et al recently reported that TQ can cause reversal of tamoxifen resistance in triple negative breast cancer cells by interfering in Akt-mediated induction of apoptosis inhibitory protein such as X-linked inhibitor of apoptosis protein (XIAP; Rajput et al, 2013).…”

“…Rajput et al recently reported that TQ can cause reversal of tamoxifen resistance in triple negative breast cancer cells by interfering in Akt-mediated induction of apoptosis inhibitory protein such as X-linked inhibitor of apoptosis protein (XIAP; Rajput et al, 2013). Chemo-potentiation of microtubule disrupting agents (e.g., docetaxel and paclitaxel) by TQ was found to be mediated by upregulation of tumor suppressor genes such as p21 and Brca1, induction of pro-apoptotic factors, and inhibition of cancer cell growth and survival promoting signaling pathways such as PI3K/Akt and MAPK/ERK (Dirican et al, 2015; Sakalar et al, 2016). …”

Combating breast cancer using combination therapy with 3 phytochemicals: Piperine, sulforaphane, and thymoquinone

“…28 Combination therapy with chemotherapeutics may work in a synergistic or additive manner, lowering the therapeutic dosage of one agent and thereby reducing toxic effects. 5 Several chemotherapeutic drugs have been tested in combination with PIP, SFN, and TQ, as described below (the summarized mechanisms of action of the combinations are shown in Table 4 [8][9][10][11]16,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] ).…”

“…It is important to note that the addition of TQ before paclitaxel sensitized 4T1 cells to paclitaxel and induced a higher cytotoxicity when compared with treatment with the 2 agents at the same time. 34 With regard to the combination of SFN and paclitaxel, Kim et al 39 observed an increase in the activation of apoptotic signaling pathway members, such as caspase-3, caspase-8, and caspase-9, and cytochrome c, in comparison with single treatment using SFN or paclitaxel. In addition, the combined treatment downregulated the nuclear factor-kappa B signaling pathway, reducing the protein expression of the apoptosis regulator Bcl-2 and phosphorylated AKT serine/ threonine kinase.…”

“…Moreover, the combination of TQ (6.25 μM, 12.5 μM, and 25 μM) and paclitaxel (10 μg/mL) induced a stronger cytotoxicity in vitro on 4T1 cells compared with each agent alone. It is important to note that the addition of TQ before paclitaxel sensitized 4T1 cells to paclitaxel and induced a higher cytotoxicity when compared with treatment with the 2 agents at the same time . With regard to the combination of SFN and paclitaxel, Kim et al observed an increase in the activation of apoptotic signaling pathway members, such as caspase‐3, caspase‐8, and caspase‐9, and cytochrome c, in comparison with single treatment using SFN or paclitaxel.…”