5-Hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone, a polymethoxyflavone, exerts antitumor effect on PI3K/Akt signaling pathway in human gastric cancer cell BGC-7901

Flavonoids and Gastric Cancer Therapy: From Signaling Pathway to Therapeutic Significance

Gastric cancer (GC) is a prevalent gastrointestinal tumor characterized by high mortality and recurrence rates. Current treatments often have limitations, prompting researchers to explore novel anti-tumor substances and develop new drugs. Flavonoids, natural compounds with diverse biological activities, are gaining increasing attention in this regard. We searched from PubMed, Web of Science, SpringerLink and other databases to find the relevant literature in the last two decades. Using "gastric cancer", "stomach cancers", "flavonoid", "bioflavonoid", "2-Phenyl-Chromene" as keywords, were searched, then analyzed and summarized the mechanism of flavonoids in the treatment of GC. It was revealed that the anti-tumor mechanism of flavonoids involves inhibiting tumor growth, proliferation, invasion, and metastasis, as well as inducing cell death through various processes such as apoptosis, autophagy, ferroptosis, and pyroptosis. Additionally, combining flavonoids with other chemotherapeutic agents like 5-FU and platinum compounds can potentially reduce chemoresistance. Flavonoids have also demonstrated enhanced biological activity when used in combination with other natural products. Consequently, this review proposes innovative perspectives for the development of flavonoids as new anti-GC agents.

Phytochemicals and mitochondria: Therapeutic allies against gastric cancer

BACKGROUND

Mitochondria are the energy factories of cells with the ability to modulate the cell cycle, cellular differentiation, signal transduction, growth, and apoptosis. Existing drugs targeting mitochondria in cancer treatment have disadvantages of drug resistance and side effects. Phytochemicals, which are widely found in plants, are bioactive compounds that could facilitate the development of new drugs for gastric cancer. Studies have shown that some phytochemicals can suppress the development of gastric cancer.

METHODS

We searched for data from PubMed, China National Knowledge Infrastructure, Web of Science, and Embase databases from initial establishment to December 2021 to review the mechanism by which phytochemicals suppress gastric cancer cell growth by modulating mitochondrial function. Phytochemicals were classified and summarized by their mechanisms of action.

RESULTS

Phytochemicals can interfere with mitochondria through several mechanisms to reach the goal of promoting apoptosis in gastric cancer cells. Some phytochemicals, e.g., daidzein and tetrandrine promoted cytochrome c spillover into the cytoplasm by modulating the members of the B-cell lymphoma-2 protein family and induced apoptotic body activity by activating the caspase protein family. Phytochemicals (e.g., celastrol and shikonin) could promote the accumulation of reactive oxygen species and reduce the mitochondrial membrane potential. Several phytochemicals (e.g., berberine and oleanolic acid) activated mitochondrial apoptotic submission via the phosphatidylinositol-3-kinase/Akt signaling pathway, thereby triggering apoptosis in gastric cancer cells. Several well-known phytochemicals that target mitochondria, including berberine, ginsenoside, and baicalein, showed the advantages of multiple targets, high efficacy, and fewer side effects.

CONCLUSIONS

Phytochemicals could target the mitochondria in the treatment of gastric cancer, providing potential directions and evidence for clinical translation. Drug discovery focused on phytochemicals has great potential to break barriers in cancer treatment.

Preparation and evaluation of self-microemulsifying delivery system containing 5-demethyltangeretin on inhibiting xenograft tumor growth in mice

5-Demethyltangeretin (5-DTAN), a polymethoxylated flavone found in citrus peels, exhibits highly potent anti-cancer activity. However, 5-DTAN is a hydrophobic compound with poor aqueous solubility, which limits its oral bioavailability and efficacy. In this study, we aimed to develop and characterize an optimal self-microemulsifying delivery system (SMEDS) formulated for 5-DTAN and to assess its anticancer activity in a xenograft model. SMEDS is a lipid-based formulation and typically comprises oil, surfactant, and co-surfactant. The results from our solubility and compatibility test revealed that ethyl oleate and d-limonene were appropriate for use as an oil phases. The optimal formulation comprised ethyl oleate/d-limonene (10%/5%), Cremophor® EL (59.5%), and PEG 400 (25.5%). With this optimal formulation, the mean particle size was 97.1 ± 6.50 nm with the highest 5-DTAN loading (3.01 ± 0.38 mg/mL) determined by photon correlation spectroscopy. The transmission electron microscopy (TEM) morphology of 5-DTAN microemulsion droplets demonstrated a spherical shape and uniform size. Our findings suggest that using 5-DTAN loading SMEDS is an effective approach for inhibiting tumor growth in colon cancer xenograft mice. In summary, this study is the first to successfully demonstrate that oral administration of 5-DTAN-loaded SMEDS serves as a promising nutraceutical for cancer prevention.

Autophagy in glioma cells: An identity crisis with a clinical perspective

Over the last decade, autophagy has emerged as one of the critical cellular systems that control homeostasis. Besides management of normal homeostatic processes, autophagy can also be induced by tissue damage stress or by rapidly progressing tumors. During tumor progression, autophagy mediates a cellular reaction to the changes inside and outside of cells, which leads to tumor adaptation. Even though the regulation of autophagy seems universal and is a well-described process, its dysregulation and role in glioma progression remain an important topic of investigation. In this review, we summarize recent evidence of autophagy regulation in brain tumor tissues and possible interconnection between signaling pathways that govern cellular responses. This perspective may help to assess the qualitative differences and various outcomes in response to autophagy stimulation.