The underlying mechanisms that can lead to the formation and development of various types of cancer are completely different and often not fully understood. However, changes in genetic and epigenetic regulatory pathways are perceived as possible causes of the emergence of many types of cancer [
14]. Accordingly, depending on the type and development of different cancers, various practical approaches have been applied for cancer treatment, including surgery, chemical drugs, radiation, immunological, targeting non-coding RNAs, and hormone therapies [
15]. Despite the developments in traditional cancer treatment platforms, clinical applications have not been significantly effective due to disadvantages such as low durability of primary treatment, high probability of recurrence, serious side effects through general toxicity, insufficient selectivity and low quality of life [
16]. Therefore, the search for modern curative procedures to combat various types of cancer with the least possible negative effects has become the focus of attention in recent years. Today, extensive research is being conducted on the anticancer properties of herbal bioactive compounds as revolutionary therapeutic agents thanks to their low toxicity, availability and affordable costs. Accordingly, one of the most promising and promising natural pharmaceuticals is thymoquinone. New studies have shown that regulation of microRNA (miRNA) expression through TQ has been accepted as a new technique in the fight against cancer [
17]. Many studies on TQ have revealed that it has a beneficial therapeutic potential on human health, especially on cancer. There is a broad consensus in cancer research that TQ has promising anticancer activity in in vitro and in vivo model studies [
18]. It has proven effective against a variety of cancer cell lines, where classical hallmarks of apoptosis such as chromatin condensation, translocation of phosphatidyl serine across the plasma membrane, and DNA fragmentation have been documented in TQ-treated cells [
19]. The development of multidrug-resistant human tumor cells, including doxorubicin-resistant breast cancer cells, led to further research with TQ to evaluate its effectiveness against these types of cells [
20]. Arafa et al. examined the anticancer effect of TQ in doxorubicin-resistant human breast cancer cells (MCF-7/DOX cells), revealing that it is significantly therapeutic in breast cancer cells [
21]. Some studies have investigated whether TQ will regulate cell proliferation and apoptosis in MCF-7/DOX cells and its anticancer effect. The proposed mechanism is that TQ induces apoptosis in doxorubicin-resistant breast cancer cells through upregulation of phosphatase and tensin homolog (PTEN) at the transcriptional level. According to studies, doxorubicin (Dox) is one of the most powerful chemotherapeutic agents and is widely used in many cancer treatments. It acts as an anti-cancer, especially breast cancer and ovarian cancer. Additionally, dox can directly kill tumor cells through DNA damage [
22], and studies show that it induces apoptosis in cancer cells through the activation of reactive oxygen species and p53 proteins [
23]. N. sativa seed oil is reported to have many medicinal benefits. It contains especially fixed oils, volatile oils, proteins, alkaloids, coumarins, saponins, minerals, carbohydrates, fiber and water [
24]. It has been reported that thymoquinone (TQ) inhibits the proliferation of many tumor cells such as colorectal carcinoma, breast adenocarcinoma, osteosarcoma, ovarian carcinoma, myeloblastic leukemia, pancreatic carcinoma and brain tumor [
25].
A recent study reported that TQ exerts an antitumor effect through disruption of pro-survival mitogen-activated protein kinase kinase 7-mitogen-activated protein kinase 1 signaling in colorectal cancer. TQ showed a direct antitumor effect and also sensitized cancer cells to other treatments [
26]. Velho-Pereira et al. [
27] reported that TQ could radiosensitize human breast carcinoma cells. Jafri et al. [
28] stated that TQ treatment in lung cancer could overcome resistance and sensitize lung cancer cells to CisPt. TQ (6 μg/mL) reduced the permeability of the plasma and mitochondrial membrane in the Caov-3 ovarian cancer cell line and increases apoptosis in ovarian cancer by reducing the nuclear area with a remarkable inhibition of both Bcl-2 and Bax, as well as inducing oxidative stress [
29]. Another study showed that the combination of TQ with cisplatin led to better results when used separately, with a higher rate of apoptosis and Bax/Bcl-2 ratio [
30]. Johnson et al. In 2019, they emphasized the importance of studying the structure-activity of TQ [
31]. TQ-cisplatin combination increased DNA fragmentation and apoptosis and decreased proliferation [
32]. Shoieb et al. found that TQ induced apoptosis in osteosarcoma cells and also reduced the number of cells in S phase.
EGFR expression is also increased in ovarian cancer, and high expression is associated with poor prognosis (221). Western blot evaluation of a study revealed that bufalin reduced the total protein and phosphorylation levels of EGFR, and the phosphorylation levels of downstream molecules of EGFR, AKT, and ERK were downregulated under 200 nmol/L bufalin stimulation (222). EGF binds to the extracellular domain of EGFR and induces EGFR dimerization ( 223 ). Amplification or high expression of EGFRs in ovarian cancer plays a role in disease progression and prognosis (221). In a study, it was proven that Bufalin could inhibit the proliferation of ovarian cancer cells by binding to EGFR through molecular docking, and it was confirmed by western blot that bufalin could inhibit the proliferation of ovarian cancer cells through the EGFR/AKT/ERK pathway (222). However, Kang et al. (224) and Jiang et al. (225) studies show that bufalin inhibits the phosphorylation of EGFR protein only in lung cancer cells without affecting the level of total EGFR protein.