To date, natural products are widely used as pharmaceutical agents for many human diseases and cancers. One of the most popular natural products that have been studied for anticancer properties is thymoquinone (TQ). As a bioactive compound of Nigella sativa, TQ has shown anticancer activities through the inhibition of cell proliferation, migration, and invasion. The anticancer efficacy of TQ is being investigated in several human cancers such as pancreatic cancer, breast cancer, colon cancer, hepatic cancer, cervical cancer, and leukemia. Even though TQ induces apoptosis by regulating the expression of pro- apoptotic and anti-apoptotic genes in many cancers, the TQ effect mechanism on such cancers is not yet fully understood. Therefore, the present review has highlighted the TQ effect mechanisms on several signaling pathways and expression of tumor suppressor genes (TSG). Data from relevant published experimental articles on TQ from 2015 to June 2020 were selected by using Google Scholar and PubMed search engines. The present study investigated the effectiveness of TQ alone or in combination with other anticancer therapeutic agents, such as tyrosine kinase inhibitors on cancers, as a future anticancer therapy nominee by using nanotechnology.

Objective: Recently, a functional PTPN22 variant (R263Q; rs33996649) was found to be associated with systemic lupus erythematosus (SLE). This study was undertaken to analyze the influence of this polymorphism on the risk of rheumatoid arthritis (RA).Methods: RA patients (n = 5,579) were recruited from outpatient clinics from 6 different countries (Spain, New Zealand, the UK, Norway, The Netherlands, and Germany). Healthy controls (n = 5,392) were recruited from the same areas. There was 100% power to detect an effect equivalent to that observed in SLE. Samples were genotyped for the PTPN22 R263Q (rs33996649) and PTPN22 R620W (rs2476601) polymorphisms using a TaqMan 5′‐allele discrimination assay. The effect of the R263Q variant was analyzed in isolation and in combination with the effect of R620W, using Unphased and Stata 10 software. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were determined.Results: The minor allele A of PTPN22 R263Q was significantly associated with a lower risk of RA in the pooled analysis of the 6 populations (P = 0.016, Mantel‐Haenszel pooled OR 0.80 [95% CI 0.67–0.96]), independent of the effect of the R620W polymorphism. Both polymorphisms had an additive effect. The more RA risk alleles carried (R263Q G allele, R620W T allele), the higher the RA risk (for 2 versus 1 risk allele P = 0.014, OR 1.28 [95% CI 1.05–1.55], for 3 versus 1 risk allele P = 6.67 × 10⁻¹¹, OR 2.01 [1.63–2.48], and for 4 versus 1 risk allele P = 6.50 × 10⁻¹¹, OR 3.55 [2.42–5.20]).Conclusion: Our findings indicate that the minor allele of the PTPN22 R263Q polymorphism is associated with a lower risk of RA. This association is independent of the well‐established association between PTPN22 R620W and RA. Both polymorphisms have an additive effect on the risk of RA.

Overexpression of c-Myc plays an essential role in leukemogenesis and drug resistance, making c-Myc an attractive target for cancer therapy. However, targeting c-Myc directly is impossible, and c-Myc upstream regulator pathways could be targeted instead. This study investigated the effects of thymoquinone (TQ), a bioactive constituent in Nigella sativa, on the activation of upstream regulators of c-Myc: the JAK/STAT and PI3K/AKT/mTOR pathways in HL60 leukemia cells. Next-generation sequencing (NGS) was performed for gene expression profiling after TQ treatment. The expression of c-Myc and genes involved in JAK/STAT and PI3K/AKT/mTOR were validated by quantitative reverse transcription PCR (RT-qPCR). In addition, Jess assay analysis was performed to determine TQ’s effects on JAK/STAT and PI3K/AKT signaling and c-Myc protein expression. The results showed 114 significant differentially expressed genes after TQ treatment (p < 0.002). DAVID analysis revealed that most of these genes’ effect was on apoptosis and proliferation. There was downregulation of c-Myc, PI3K, AKT, mTOR, JAK2, STAT3, STAT5a, and STAT5b. Protein analysis showed that TQ also inhibited JAK/STAT and PI3K/AKT signaling, resulting in inhibition of c-Myc protein expression. In conclusion, the findings suggest that TQ potentially inhibits proliferation and induces apoptosis in HL60 leukemia cells by downregulation of c-Myc expression through inhibition of the JAK/STAT and PI3K/AKT signaling pathways.

Constitutive activation of Janus tyrosine kinase-signal transducer and activator of transcription (JAK/STAT) and Phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathways plays a crucial role in the development of acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). Thymoquinone (TQ), one of the main constituents of Nigella sativa, has shown anti-cancer activities in several cancers. However, the inhibitory effect mechanism of TQ on leukemia has not been fully understood. Therefore, this study aimed to investigate the effect of TQ on JAK/STAT and PI3K/Akt/mTOR pathways in MV4-11 AML cells and K562 CML cells. FLT3-ITD positive MV4-11 cells and BCR-ABL positive K562 cells were treated with TQ. Cytotoxicity assay was assessed using WSTs-8 kit. The expression of the target genes was evaluated using RT-qPCR. The phosphorylation status and the levels of proteins involved in JAK/STAT and PI3K/Akt/mTOR pathways were investigated using Jess western analysis. TQ induced a dose and time dependent inhibition of K562 cells proliferation. TQ significantly downregulated PI3K, Akt, and mTOR and upregulated PTEN expression with a significant inhibition of JAK/STAT and PI3K/Akt/mTOR signaling. In conclusion, TQ reduces the expression of PI3K, Akt, and mTOR genes and enhances the expression of PTEN gene at the mRNA and protein levels. TQ also inhibits JAK/STAT and PI3K/Akt/mTOR pathways, and consequently inhibits proliferation of myeloid leukemia cells, suggesting that TQ has potential anti-leukemic effects on both AML and CML cells.

Epigenetic silencing of tumor suppressor genes (TSGs) plays an essential role in cancer pathogenesis, including acute myeloid leukemia (AML). All of SHP-1, SOCS-1, and SOCS-3 are TSGs that negatively regulate JAK/STAT signaling. Enhanced re-expression of TSGs through de-methylation represents a therapeutic target in several cancers. Thymoquinone (TQ) is a major component of Nigella sativa seeds with anticancer effects against several cancers. However, the effects of TQ on DNA methylation are not entirely understood. This study aimed to evaluate the ability of TQ to re-express SHP-1, SOCS-1, and SOCS-3 in MV4-11 AML cells through de-methylation. Cytotoxicity, apoptosis, and cell cycle assays were performed using WSTs-8 kit, Annexin V-FITC/PI apoptosis detection kit, and fluorometric-red cell cycle assay kit, respectively. The methylation of SHP-1, SOCS-1, and SOCS-3 was evaluated by pyrosequencing analysis. The expression of SHP-1, SOCS-1, SOCS-3, JAK2, STAT3, STAT5A, STAT5B, FLT3-ITD, DNMT1, DNMT3A, DNMT3B, TET2, and WT1 was assessed by RT-qPCR. The molecular docking of TQ to JAK2, STAT3, and STAT5 was evaluated. The results revealed that TQ significantly inhibited the growth of MV4-11 cells and induced apoptosis in a dose- and time-dependent manner. Interestingly, the results showed that TQ binds the active pocket of JAK2, STAT3, and STAT5 to inhibit their enzymatic activity and significantly enhances the re-expression of SHP-1 and SOCS-3 through de-methylation. In conclusion, TQ curbs MV4-11 cells by inhibiting the enzymatic activity of JAK/STAT signaling through hypomethylation and re-expression of JAK/STAT negative regulators and could be a promising therapeutic candidate for AML patients.