Thymoquinone sensitizes human hepatocarcinoma cells to TRAIL-induced apoptosis via oxidative DNA damage.

Hepatocellular carcinoma (HCC) remains one of the most predominant types of digestive system malignancies worldwide. TNF-related apoptosis-inducing ligand (TRAIL) is a biological cytokine with the mentioned specificity, but some tumor cells' resistance limits its use as a therapeutic approach. The present study aimed to investigate thymoquinone (TQ) and TRAIL's combined effect and the potential mechanisms in human hepatic HepG2 carcinoma cells. Cell viability and IC50 dose for TQ and TRAIL, alone and in combination, were determined using the MTT method. ELISA evaluated the expression levels of 8-Hydroxy-2'-deoxyguanosine. The apoptosis rate was assessed by flow cytometry, ELISA cell death assay, and caspase 8 activity assays. The mRNA and protein evaluation of candidate genes, including survivin, Bcl-2, XIAP, c-IAP1, c-IAP2, and c-FLIP, were accomplished before and after the treatment using qRT-PCR and Western blot analysis, respectively. Our results showed that TQ synergistically increased TRAIL's cell toxic effects as follows: TQ plus TRAIL > TRAIL > TQ. TQ could sensitize the HepG2 cells against the TRAIL-induced apoptosis and amplify the caspase 8 activity. This outcome is achieved by decreasing the mRNA and protein expression levels of anti-apoptotic genes. Our findings suggest that TQ can sensitize the human HCC cell line HepG2 against TRAIL by inducing the death receptor pathway. Moreover, these agents' combinational therapy might promise a therapeutic regimen for improving the clinical efficacy of TRAIL-induced apoptosis in patients with HCC.

Zhang R ，Wu T ，Zheng P ，Liu M ，Xu G ，Xi M ，Yu J ... -  《-》

Thymoquinone suppression of the human hepatocellular carcinoma cell growth involves inhibition of IL-8 expression, elevated levels of TRAIL receptors, oxidative stress and apoptosis.

Ashour AE ，Abd-Allah AR ，Korashy HM ，Attia SM ，Alzahrani AZ ，Saquib Q ，Bakheet SA ，Abdel-Hamied HE ，Jamal S ，Rishi AK ... -  《-》

Thymoquinone upregulates TRAIL/TRAILR2 expression and attenuates hepatocellular carcinoma in vivo model.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. Indeed, chemotherapeutic drugs-induced systemic toxicity results in suboptimal cancer treatment. Consequently, there is a need for exploring of a safe and effective therapy for cancer patients. This study aimed to evaluate the hepatoprotective effect of thymoquinone (TQ) against thioacetamide (TAA)-induced HCC. Also, we investigated TQ's ability to sensitize cancer cells toward TRAIL/TRAILR2 apoptotic pathway. Forty male Sprague Dawley rats were divided into 4 groups (n = 10) as follows: control group, CMC group, HCC group and HCC + TQ group. Serum levels of liver function biomarkers and Alpha-Fetoprotein (AFP), as well as hepatic levels of glutathione (GSH) and Alpha-Fetoprotein (MDA) were measured. Transforming growth factor-beta 1 (TGF-β1), TRAILR2, TRAIL, caspase-3, caspase-9, caspase-8 and B cell lymphoma-2 (Bcl-2) mRNA levels were assessed by Quantitative, Real-Time PCR. Fibrosis percentage and necroinflammation were quantified by histopathological examination. Our results indicated improvement in liver functions, decrease in AFP level and attenuation of HCC progression in TQ treated rats. TQ upregulated TRAIL/TRAILR2 and subsequently enhanced apoptosis as hinted by caspase-3 upregulation and Bcl-2 downregulation. Also, TQ decreased TGF-β1 gene expression level. Moreover, HCC + TQ group showed significant increase in hepatic GSH level and marked decrease in hepatic MDA level. This study proved that TQ is able to suppress HCC development via decreasing oxidative stress, suppression of TGF-β1 and induction of TRAIL-mediated apoptosis.

Helmy SA ，El-Mesery M ，El-Karef A ，Eissa LA ，El Gayar AM ... -  《-》

Chrysin sensitizes osteosarcoma cells against TRAIL-induced apoptosis.

Identifying novel curative and preventive approaches that can specifically target the osteosarcoma cells (OS) without affecting the normal cells is appreciable. The aim of this study is to investigate the combined effect of chrysin as an apigenin analog with high therapeutic potential and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the treatment of Saos-2 and MG-63 cells. Cell viability were determined using MTT method. The rate of apoptosis was assessed by enzyme-linked immunosorbent assay (ELISA) cell death assay and caspase 8 activity assays. The messenger RNA (mRNA) and protein evaluation of candidate genes include Bcl-2, XIAP, c-IAP1, c-IAP2, and c-FLIP were accomplished before and after the treatment by quantitative real-time polymerase chain reaction (PCR) and Western blot analysis, respectively. Our results showed that chrysin synergistically increased the cytotoxic effects of TRAIL as follows: Chrysin plus TRAIL > TRAIL > Chrysin. Chrysin could sensitize both cells against the TRAIL-induced apoptosis, amplify the caspase 8 activity and this outcome is achieved by decreasing the expression levels of antiapoptotic genes. Our findings suggest that Chrysin can sensitize the OS cell lines against TRAIL through induction of the death receptor pathway. Moreover, the combinational therapy of these agents might be the promising therapeutic regimen for improving the clinical efficacy of TRAIL-induced apoptosis in patients with OS.

Xie B ，Yang J ，Zhang J 《-》

Salirasib sensitizes hepatocarcinoma cells to TRAIL-induced apoptosis through DR5 and survivin-dependent mechanisms.

Charette N ，De Saeger C ，Horsmans Y ，Leclercq I ，Stärkel P ... -  《Cell Death & Disease》