Role of gambogic acid and NaI131 in A549/DDP cells

Effects of Sinapic Acid Combined with Cisplatin on the Apoptosis and Autophagy of the Hepatoma Cells HepG2 and SMMC-7721

Sinapic acid (Sa) is a small-molecule phenolic acid compound predominant in fruits, vegetables, and grains. This study investigated the antitumor effects of cisplatin (DDP) combined with Sa (Sa/DDP) on the hepatic cancer cells (HCC), HepG2 and SMMC-7721. The HepG2 and SMMC-7721 cells were treated with Sa or Sa/DDP, and the cell proliferation and cell cycle were detected using the MTT assay. The cell migration was detected using the transwell and scratch assays, while apoptosis and autophagy were detected using Hoechst, MDC, and Annexin V-FITC/PI staining. The protein expression was quantitated using the western blot. Sa/DDP was found to not only inhibit cancer cell proliferation and migration but also induce cell apoptosis. Simultaneously, the Sa/DDP combination was found to activate autophagy, and the HCQ autophagy inhibitor enhanced the apoptosis in the Sa/DDP-induced liver cancer cells. The combined use of Sa and DDP makes it an attractive adjuvant therapy strategy for tumors, establishing the prospect of phenolic acid compounds for the adjuvant treatment of hepatocellular carcinoma.

Combined effects of low-dose gambogic acid and NaI131 in drug-resistant non-small cell lung cancer cells

Radioactive seed brachytherapy is a method for treating drug-resistant, late-stage non-small cell lung cancer (NSCLC). To elucidate the mechanism of low-dose gambogic acid (GA) and NaI¹³¹ in drug-resistant NSCLC cells, the human NSCLC A549 cell line and the drug-resistant A549/cisplatin (DDP) and A549/Taxol cell lines were treated with NaI¹³¹, low-dose GA or a combination of both in the present study; the control group of each cell line was treated with phosphate-buffered saline (PBS). Following treatment, cell proliferation, apoptosis and cell cycle analysis was performed. Apoptosis-related proteins, namely CDK1, cyclin B, mutant p53 (mtp53), heat shock protein 90 (HSP90), Bax and Bcl-2, and P-glycoprotein 1 (P-gp), which is known to confer resistance to chemotherapy, were detected using western blotting and immunofluorescence analysis. mRNA levels of p53 and HSP90 were measured using reverse transcription-quantitative PCR. Compared with the PBS control group, the A549, A549/DDP and A549/Taxol cells treated with NaI¹³¹, GA or a combination of the drugs exhibited G₂/M arrest and increased percentages of total apoptotic cells, as well as significantly decreased protein levels of CDK1, cyclin B, mtp53, HSP90, Bcl-2 and P-gp, increased protein levels of Bax and decreased mRNA levels of p53 and HSP90. The changes in the combination group were the most evident and were significantly different from the other groups (P<0.001). In conclusion, low-dose GA may be a potential radionuclide sensitizer.

Xanthones as P-glycoprotein modulators and their impact on drug bioavailability

Introduction: P-glycoprotein (P-gp) is an important efflux pump responsible for the extruding of many endogenous and exogenous substances out of the cells. P-gp can be modulated by different molecules - including xanthone derivatives - to surpass the multidrug resistance (MDR) phenomenon through P-gp inhibition, or to serve as an antidotal strategy in intoxication scenarios through P-gp induction/activation.Areas covered: This review provides a perspective on P-gp modulators, with particular focus on xanthonic derivatives, highlighting their ability to modulate P-gp expression and/or activity, and the potential impact of these effects on the pharmacokinetics, pharmacodynamics and toxicity of P-gp substrates.Expert opinion: Xanthones, of natural or synthetic origin, are able to modulate P-gp, interfering with its protein synthesis or with its mechanism of action, by decreasing or increasing its efflux capacity. These modulatory effects make the xanthonic scaffold a promising source of new derivatives with therapeutic potential. However, the mechanisms beyond the xanthones-mediated P-gp modulation and the chemical characteristics that make them more potent P-gp inhibitors or inducers/activators are still understudied. Furthermore, a new window of opportunity exists in the neuropathologies field, where xanthonic derivatives with potential to modulate P-gp should be further explored to optimize the prevention/treatment of brain pathologies.

Perspectives and controversies regarding the use of natural products for the treatment of lung cancer

Lung cancer is the leading cause of cancer‐related mortality both in men and women and accounts for 18.4% of all cancer‐related deaths. Although advanced therapy methods have been developed, the prognosis of lung cancer patients remains extremely poor. Over the past few decades, clinicians and researchers have found that chemical compounds extracted from natural products may be useful for treating lung cancer. Drug formulations derived from natural compounds, such as paclitaxel, doxorubicin, and camptothecin, have been successfully used as chemotherapeutics for lung cancer. In recent years, hundreds of new natural compounds that can be used to treat lung cancer have been found through basic and sub‐clinical research. However, there has not been a corresponding increase in the number of drugs that have been used in a clinical setting. The probable reasons may include low solubility, limited absorption, unfavorable metabolism, and severe side effects. In this review, we present a summary of the natural compounds that have been proven to be effective for the treatment of lung cancer, as well as an understanding of the mechanisms underlying their pharmacological effects. We have also highlighted current controversies and have attempted to provide solutions for the clinical translation of these compounds.

Gambogic Acid Inhibits the Progression of Gastric Cancer via circRNA_ASAP2/miR-33a-5p/CDK7 Axis

Background

Gastric cancer (GC) is a major cancer-related mortality disease. Gambogic acid (GA) has been investigated to inhibit cancer progression. In the present study, the molecular mechanism of GA in regulating GC progression was studied.

Methods

The expression levels of circular RNA ASAP2 (circ_ASAP2), miR-33a-5p and cyclin-dependent kinases 7 (CDK7) were detected by quantitative real-time polymerase reaction (qRT-PCR). CDK7 protein level was evaluated by Western blot. Cell colony formation assay, 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, transwell assay and flow cytometry analysis were employed to reveal the functional effects among circ_ASAP2, miR-33a-5p and CDK7 on GA-induced GC progression. Mechanistically, the binding relationship between miR-33a-5p and circ_ASAP2 or CDK7 was predicted with starBase v3.0 online database and verified by dual-luciferase reporter assay. In vivo tumor formation assay was used to explain the impacts of GA treatment on GC growth in vivo.

Results

Circ_ASAP2 and CDK7 expression were downregulated in GA-induced GC cells compared with GC cells. MiR-33a-5p expression was upregulated in GA-induced GC cells relative to GC cells. The protein expression level of CDK7 was lower in GA-induced GC cells than that in GC cells. Further, circ_ASAP2 overexpression decreased GA-induced inhibition effects on cell proliferation, migration and invasion and GA-induced promotion effect on cell apoptosis in both AGS and HGC-27 cells, whereas this phenomenon was reversed by miR-33a-5p. In addition, circ_ASAP2 functioned as a sponge of miR-33a-5p and miR-33a-5p was associated with CDK7. Furthermore, GA treatment inhibited GC growth in vivo.

Conclusion

Circ_ASAP2 overexpression promoted cell proliferation, migration and invasion, whereas inhibited cell apoptosis by upregulating CDK7 expression through binding to miR-33a-5p in GA-induced GC cells. This study provided a theoretical basis in GC treatment with GA.

Photodynamic Therapy Using a Novel Phosphorus Tetraphenylporphyrin Induces an Anticancer Effect via Bax/Bcl-xL-related Mitochondrial Apoptosis in Biliary Cancer Cells

Photodynamic therapy (PDT) uses photosensitizer activation by light of a specific wavelength, and is a promising treatment for various cancers; however, the detailed mechanism of PDT remains unclear. Therefore, we investigated the anticancer effect of PDT using a novel phosphorus tetraphenylporphyrin (Ptpp) in combination with light emitting diodes (Ptpp-PDT) in the NOZ human biliary cancer cell line. Cell viability and apoptosis were examined by MTT assay, flow cytometry and TUNEL assay for 24 hr after Ptpp-PDT. MitoTracker and JC-1 were used as markers of mitochondrial localization and membrane potential. The levels of mitochondrial oxidative phosphorylation (OXPHOS) complexes, Bcl-2 family proteins, cytochrome c and cleaved caspase-3 were examined by western blotting and immunohistochemistry. The results revealed that Ptpp localized to mitochondria, and that Ptpp-PDT efficiently decreased cell viability in a dose- and time-dependent manner. JC-1 and OXPHOS complexes decreased, but apoptotic cells increased from 6 to 24 hr after Ptpp-PDT. A decrease in Bcl-xL and increases in Bax, cytochrome c and cleaved caspase-3 were also found from 6 to 24 hr after Ptpp-PDT. Based on these results, we conclude that Ptpp-PDT induces anticancer effects via the mitochondrial apoptotic pathway by altering the Bax/Bcl-xL ratio, and could be an effective treatment for human biliary cancer.

Antitumor Activity of Thermosensitive Hydrogels Packaging Gambogic Acid Nanoparticles and Tumor-Penetrating Peptide iRGD Against Gastric Cancer

Introduction

Gambogic acid (GA) is proved to have anti-tumor effects on gastric cancer. Due to poor solubility, non-specific biological distribution, toxicity to normal tissues and short half-life, it is hard to be applied into the clinic. To overcome these issues, we developed a thermosensitive and injectable hydrogel composed of hydroxypropyl cellulose, silk fibroin and glycerol, with short gelling time, good compatibility and sustained release, and demonstrated that the hydrogel packaged with gambogic acid nanoparticles (GA-NPs) and tumor-penetrating peptide iRGD could improve the anti-tumor activity.

Methods

The Gelling time and micropore size of the hydrogels were regulated through different concentrations of glycerol. Controlled release characteristics of the hydrogels were evaluated with a real-time near-infrared fluorescence imaging system. Location of nanoparticles from different carriers was traced by confocal laser scanning microscopy. The in vivo antitumor activity of the hydrogels packaging GA-NPs and iRGD was evaluated by investigating tumor volume and tumor size.

Results

The thermo-sensitive properties of hydrogels were characterized by 3-4 min, 37°C, when glycerol concentration was 20%. The hydrogels physically packaged with GA-NPs and iRGD showed higher fluorescence intensity than other groups. The in vivo study indicated that the co-administration of GA-NPs and iRGD by hydrogels had higher antitumor activity than the GA-loaded hydrogels and free GA combining with iRGD. Free GA group showed few antitumor effects. Compared with the control group, the body weight in other groups had no obvious change, and the count of leukocytes and hemoglobin was slightly decreased.

Discussion

The hydrogel constructed iRGD and GA-NPs exerted an effective anti-tumor effect possibly due to retention effect, local administration and continuous sustained release of iRGD promoting the penetration of nanoparticles into a deep part of tumors. The delivery system showed little systemic toxicity and would provide a promising strategy to improve anti-gastric cancer efficacy.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.