Thymoquinone subdues tumor growth and potentiates the chemopreventive effect of 5-fluorouracil on the early stages of colorectal carcinogenesis in rats

Abstract

Colorectal cancer (CRC) is one of the most prevalent cancers and has a high mortality rate. Insensitivity and the limited therapeutic efficacy of its standard chemotherapeutic drug, 5-fluorouracil (5-FU), represents an important challenge in CRC treatment. The robust antitumor properties of thymoquinone (TQ), the main bioactive constituent of Nigella sativa, have recently been demonstrated on different cancers. We investigated whether TQ could potentiate the chemopreventive effect of 5-FU to eradicate the early stages of CRC and elucidated its underlying mechanisms. An intermediate-term (15 weeks) model of colorectal tumorigenesis was induced in male Wistar rats by azoxymethane (AOM), and the animals were randomly and equally divided into five groups: control, AOM, AOM/5-FU, AOM/TQ, and AOM/5-FU/TQ. TQ (35 mg/kg/d; 3 d/wk) was given during the seventh and 15th weeks post-AOM injection, while 5-FU was given during the ninth and tenth weeks (12 mg/kg/d for 4 days; then 6 mg/kg every other day for another four doses). At week 15, the resected colons were subjected to macroscopic, histopathological, molecular, and immunohistochemical examinations. Interestingly, 5-FU/TQ combination therapy resulted in a more significant reduction on AOM-induced colorectal tumors and large aberrant crypts foci than treatment with the individual drugs. Mechanistically, 5-FU and TQ remarkably cooperated to repress the expression of procancerous Wnt, β-catenin, NF-κB, COX-2, iNOS, VEGF, and TBRAS and upregulate the expression of anti-tumorigenesis DKK-1, CDNK-1A, TGF-β1, TGF-βRII, Smad4, and GPx. Overall, our findings present the first report describing the in vivo enhancement effect of combined TQ and 5-FU against early stages of CRC; however, further studies are required to determine the value of this combination therapy in an advanced long-term model of CRC and also to realize its clinical potential.

Pharmacotherapy with Thymoquinone Improved Pancreatic β-Cell Integrity and Functional Activity, Enhanced Islets Revascularization, and Alleviated Metabolic and Hepato-Renal Disturbances in Streptozotocin-Induced Diabetes in Rats

“…Interestingly, data of the present study are in harmony whereas therapy with TQ exhibited profound restoration of survivin expression with concomitant downregulation of caspase-3 levels in the pancreatic tissues of STZ-diabetic rats; proposing the anti-apoptotic role mediated by TQ against the peculiar β-cell cytotoxic-, apoptotic-, and destructive effects induced by STZ in this model [22,23,24]. Although it has been shown [27,35] that TQ is a potent antineoplastic agent that induces apoptosis in cancer cells, its distinguished anti-apoptotic properties, via decreasing apoptotic drivers and increasing anti-apoptotic proteins, have also been observed in several non-cancerous modalities, suggesting its paradoxical anti-apoptotic and apoptotic dual roles in non-cancerous and cancerous cell injuries, respectively [19,36,37,38,39]. …”

“…per day) was freshly prepared in 0.1% dimethyl sulfoxide and diluted in normal saline daily. The dosage schedule of TQ was selected based on our previous pilot study and our recently published work [27]. TQ was orally administered by gastric gavage for 5 consecutive weeks.…”

“…Five micrometer tissue sectioning slices were stained with hematoxylin and eosin (H&E) and examined under light microscopy by a pathologist in a blinded fashion. Pancreatic tissue sections of all animal groups were also subjected to immunohistochemical (IHC) analysis to stain the pancreatic cells expressing insulin, endothelial marker CD31, or anti-apoptotic protein “survivin.” After deparaffinization, rehydration, antigen retrieval, and endogenous peroxidase blocking steps [27], the tissue sections were blocked for 30 min with normal blocking serum and then incubated overnight at 4°C with 1:100 dilution of primary antibodies (Santa-Cruz Biotechnology Inc., Burlingame, CA, USA) against rat insulin (Catalog No. SC-7839), CD31 (Catalog No.…”

The fibrolytic potentials of vitamin D and thymoquinone remedial therapies: insights from liver fibrosis established by CCl4 in rats

“…Cholecalciferol (4500 IU/ml) was prepared by adding 7.8 to 27.2 ml sterile saline every morning to form a final concentration of 1000 IU/ml and 0.5 ml (500 IU) were given orally every other day (3 days/week) to each rat in the ‘VitD’ and ‘VitD/TQ’ groups as previously described [ 30 ]. TQ (240 mg) was also freshly dissolved on the day of use in 8 ml of 0.5 % DMSO, diluted in 8 ml olive oil to prepare a final concentration of 15 mg/ml and then administered orally every other day (3 days/week) at the dose of 35 mg/kg/day (0.5 ml/rat) using gastric gavage [ 31 ]. The rats in the ‘NC’, ‘L-PC’ and ‘VitD’ groups also received a mixture of olive oil and 0.5 % of DMSO orally similar to the ‘TQ’ and ‘VitD/TQ’ groups.…”

In vivo attenuation of angiogenesis in hepatocellular carcinoma by Nigella sativa

“…Chronic and acute toxicity studies have recently confirmed the safety of N. sativa oil, especially when given orally, and that of thymoquinone, its most abundant active component (17,(20)(21)(22)(23). Recently, the therapeutic and molecular potential of thymoquinone in lung, pancreatic, gastric, and colorectal cancers showed that it inhibits tumor angiogenesis and tumor growth (19,(24)(25)(26)(27)(28)(29)(30)(31), but no studies have investigated the molecular effect of N. sativa seed extracts on angiogenesis.…”