Sensitisation of ovarian cancer cells to cisplatin by flavonoids fromScutellaria barbata

Co-treatment of silymarin and cisplatin inhibited cell proliferation, induced apoptosis in ovarian cancer

BACKGROUND

Ovarian cancer is one of the most lethal gynecological cancers among women worldwide. Cisplatin (Cis) is an effective chemotherapeutic agent used to treat several types of cancer. Silymarin (SLM) is an extract of medicinal plant Silybum marianum (milk thistle) with anti-inflammatory, anti-angiogenesis, antioxidant, and anticancer properties used alone or in combination with other drugs.

OBJECTIVE

This study aimed to explore the effects of co-treatment with SLM and Cis on A2780 human ovarian cancer cell lines.

METHODS

In this study, A2780 cells were treated with various concentrations of SLM and Cis, separately and in combination. Cell cytotoxicity, scratch, clonogenic, and flow-cytometry assays were accomplished to estimate cell viability, migration, colony formation, and apoptosis, respectively. Real-time PCR was utilized to determine the expression levels of miR-155 and miR-27a.

RESULTS

SLM significantly reduced the proliferation of A2780 cells in a concentration- and time-dependent manner. Combination treatment with SLM and Cis was more potent than either single treatment in reducing viability, suppressing migration, inhibiting colony formation, and promoting the induction of apoptosis. Additionally, gene expression analysis revealed a significant decline in the expression levels of miR-155 and miR-27a in response to all separate and combined treatments, and co-treatment was more effective than individual treatments in altering miRNAs expression.

CONCLUSION

Based on our findings, SLM boosts the anticancer activity of Cis and mitigates its side effects. Thus, the co-treatment of SLM and Cis can be proposed as a promising therapeutic strategy for further investigation.

Synergistic Effects of New Curcumin Analog (PAC) and Cisplatin on Oral Cancer Therapy

Oral cancer has traditionally been treated with surgery, radiotherapy, chemotherapy, or a combination of these therapies. Although cisplatin, a chemotherapy drug, can effectively kill oral cancer cells by forming DNA adducts, its clinical use is limited due to adverse effects and chemo-resistance. Therefore, there is a need to develop new, targeted anticancer drugs to complement chemotherapy, allowing for reduced cisplatin doses and minimizing adverse effects. Recent studies have shown that 3,5-Bis (4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidine (PAC), a new curcumin analog, possesses anticancer properties and could be considered a complementary or alternative therapy. In this study, we aimed to assess the potential complementary effects of PAC in combination with cisplatin for treating oral cancer. We conducted experiments using oral cancer cell lines (Ca9-22) treated with different concentrations of cisplatin (ranging from 0.1 μM to 1 μM), either alone or in conjunction with PAC (2.5 and 5 μM). Cell growth was measured using the MTT assay, while cell cytotoxicity was evaluated using an LDH assay. Propidium iodide and annexin V staining were employed to examine the impact on cell apoptosis. Flow cytometry was used to investigate the effects of the PAC/cisplatin combination on cancer cell autophagy, oxidative stress, and DNA damage. Additionally, a Western Blot analysis was performed to assess the influence of this combination on pro-carcinogenic proteins involved in various signaling pathways. The results demonstrated that PAC enhanced the efficacy of cisplatin in a dose-dependent manner, leading to a significant inhibition of oral cancer cell proliferation. Importantly, treatment with PAC (5 μM) alongside different concentrations of cisplatin reduced the IC50 of cisplatin tenfold. Combining these two agents increased apoptosis by further inducing caspase activity. In addition, the concomitant use of PAC and cisplatin enhances oral cancer cell autophagy, ROS, and MitoSOX production. However, combined PAC with cisplatin inhibits the mitochondrial membrane potential (ΔΨm), which is a marker for cell viability. Finally, this combination further enhances the inhibition of oral cancer cell migration via the inhibition of epithelial-to-mesenchymal transition genes, such as E-cadherin. We demonstrated that the combination of PAC and cisplatin markedly enhanced oral cancer cell death by inducing apoptosis, autophagy, and oxidative stress. The data presented indicate that PAC has the potential to serve as a powerful complementary agent to cisplatin in the treatment of gingival squamous cell carcinomas.

Recent studies on chemical constituents of Ophiorrhiza plants

Ophiorrhiza plants (Family Rubiaceae) are known to produce diverse monoterpenoid indole alkaloids including camptothecin with potent antitumor activity. This review contains a summary of recent chemical studies reported over the past 10 years regarding alkaloids (monoterpenoid indole and tetrahydroisoquinoline alkaloids, and cyclopeptide) in Ophiorrhiza plants. In addition, the alkaloid biosynthetic pathways based on their reported structures were proposed.

Pharmacological Effects of Cisplatin Combination with Natural Products in Cancer Chemotherapy

Cisplatin and other platinum-based drugs, such as carboplatin, ormaplatin, and oxaliplatin, have been widely used to treat a multitude of human cancers. However, a considerable proportion of patients often relapse due to drug resistance and/or toxicity to multiple organs including the liver, kidneys, gastrointestinal tract, and the cardiovascular, hematologic, and nervous systems. In this study, we sought to provide a comprehensive review of the current state of the science highlighting the use of cisplatin in cancer therapy, with a special emphasis on its molecular mechanisms of action, and treatment modalities including the combination therapy with natural products. Hence, we searched the literature using various scientific databases., such as MEDLINE, PubMed, Google Scholar, and relevant sources, to collect and review relevant publications on cisplatin, natural products, combination therapy, uses in cancer treatment, modes of action, and therapeutic strategies. Our search results revealed that new strategic approaches for cancer treatment, including the combination therapy of cisplatin and natural products, have been evaluated with some degree of success. Scientific evidence from both in vitro and in vivo studies demonstrates that many medicinal plants contain bioactive compounds that are promising candidates for the treatment of human diseases, and therefore represent an excellent source for drug discovery. In preclinical studies, it has been demonstrated that natural products not only enhance the therapeutic activity of cisplatin but also attenuate its chemotherapy-induced toxicity. Many experimental studies have also reported that natural products exert their therapeutic action by triggering apoptosis through modulation of mitogen-activated protein kinase (MAPK) and p53 signal transduction pathways and enhancement of cisplatin chemosensitivity. Furthermore, natural products protect against cisplatin-induced organ toxicity by modulating several gene transcription factors and inducing cell death through apoptosis and/or necrosis. In addition, formulations of cisplatin with polymeric, lipid, inorganic, and carbon-based nano-drug delivery systems have been found to delay drug release, prolong half-life, and reduce systemic toxicity while other formulations, such as nanocapsules, nanogels, and hydrogels, have been reported to enhance cell penetration, target cancer cells, and inhibit tumor progression.

Luteolin-3'-O-Phosphate Inhibits Lipopolysaccharide-Induced Inflammatory Responses by Regulating NF-κB/MAPK Cascade Signaling in RAW 264.7 Cells

Luteolin (LT), present in most plants, has potent anti-inflammatory properties both in vitro and in vivo. Furthermore, some of its derivatives, such as luteolin-7-O-glucoside, also exhibit anti-inflammatory activity. However, the molecular mechanisms underlying luteolin-3′-O-phosphate (LTP)-mediated immune regulation are not fully understood. In this paper, we compared the anti-inflammatory properties of LT and LTP and analyzed their molecular mechanisms of action; we obtained LTP via the biorenovation of LT. We investigated the anti-inflammatory activities of LT and LTP in macrophage RAW 264.7 cells. We confirmed from previously reported literature that LT inhibits the production of nitric oxide and prostaglandin E₂, as well as the expression of inducible NO synthetase and cyclooxygenase-2. In addition, expressions of inflammatory genes and mediators, such as tumor necrosis factor-α, interleukin-6, and interleukin-1β, were suppressed. LTP showed anti-inflammatory activity similar to LT, but better anti-inflammatory activity in all the experiments, while also inhibiting mitogen-activated protein kinase and nuclear factor-kappa B more effectively than LT. At a concentration of 10 μM, LTP showed differences of 2.1 to 44.5% in the activity compared to LT; it also showed higher anti-inflammatory activity. Our findings suggest that LTP has stronger anti-inflammatory activity than LT.

Effects of naringin on reversing cisplatin resistance and the Wnt/-catenin pathway in human ovarian cancer SKOV3/CDDP cells

Objective

Ovarian cancer is one of three malignant tumors of the female reproductive system. Our previous studies showed that the traditional Chinese medicine naringin significantly inhibited the proliferation of platinum-resistant ovarian cancer cells in vitro, and that the mechanism may be related to the NF-κB pathway.

Methods

The MTT assay was used to detect the sensitivity of SKOV3 and SKOV3/CDDP cells to cisplatin, the effect of different naringin concentrations on the proliferation of SKOV3/CDDP cells, and the reversal of cisplatin resistance in naringin-treated SKOV3/CDDP cells. Western blotting was used to detect β-catenin, c-Myc, and cyclin D1 protein levels in the different cell lines.

Results

MTT results showed that different concentrations of naringin inhibited the proliferation of SKOV3 and SKOV3/CDDP cells, and that the inhibition increased with increasing concentrations and prolonged incubation times. Western blotting revealed that compared with controls (SKOV3/CDDP-0), β-catenin, c-Myc and cyclin D1 proteins levels were significantly decreased in SKOV3/CDDP-C, SKOV3/CDDP-N 20, and SKOV3/CDDP-CN 20 cells, suggesting that naringin inhibited the proliferation of SKOV3/CDDP cells in a concentration and time dependent manner.

Conclusions

Non-cytotoxic naringin reduced the expression of β-catenin, c-Myc, and cyclin D1 in SKOV3/CDDP cells and partially reversed cisplatin resistance in SKOV3/CDDP CN 20 cells.

Pathways Related to the Anti-Cancer Effects of Metabolites Derived from Cerrado Biome Native Plants: An Update and Bioinformatics Analysis on Oral Squamous Cell Carcinoma

BACKGROUND

Oral cancer is a significant health problem worldwide. Oral squamous cell carcinoma (OSCC) is a malignant neoplasm of epithelial cells that mostly affects different anatomical sites in the head and neck and derives from the squamous epithelium or displays similar morphological characteristics. Generally, OSCC is often the end stage of several changes in the stratified squamous epithelium, which begin as epithelial dysplasia and progress by breaking the basement membrane and invading adjacent tissues. Several plant-based drugs with potent anti-cancer effects are considered inexpensive treatments with limited side effects for cancer and other diseases.

OBJECTIVE

The aim of this review is to explore whether some Brazilian plant extracts or constituents exhibit anti-tumorigenic activity or have a cytotoxic effect on human oral carcinoma cells.

METHODS

Briefly, OSCC and several metabolites derived from Brazilian plants (i.e., flavonoids, vinblastine, irinotecan, etoposide and paclitaxel) were used as keywords to search the literature on PubMed, GenBank and GeneCards.

RESULTS

The results showed that these five chemical compounds found in Cerrado Biome plants exhibit anti-neoplastic effects. Evaluating the compounds revealed that they play a main role in the regulation of cell proliferation.

CONCLUSION

Preserving and utilising the biodiversity of our planet, especially in unique ecosystems, such as the Cerrado Biome, may prove essential to preserving and promoting human health in modern contexts.

Scutellaria barbata: A Review on Chemical Constituents, Pharmacological Activities and Clinical Applications

Scutellaria barbata has a long history of medical use in Traditional Chinese Medicine for removing heat and toxic material, promoting blood circulation and removing blood stasis, and inducing diuresis to reduce edema. Recent pharmacology investigations have provided evidence for its anti-cancer, bacteriostasis, anti-virus, anti-inflammation, anti-oxidation and immunity enhancement properties. The efficacy of activating blood circulation and removing blood stasis has unique advantages in the treatment of cardiovascular and cerebrovascular diseases. A total of 84 compounds have been isolated from S. barbata and are characterized mainly as flavonoids, diterpenoids, followed by polysaccharide, volatile oil and steroids. Peer-reviewed articles published over the last few years were gathered by consulting the databases PubMed, Elsevier, Springer, and Chinese Herbal Classics. This review mainly focuses on the pharmacologically active constituents isolated from S. barbata，which have been subjected to in vitro and/or in vivo studies. Although, the chemical components, pharmacological activities, toxicology, clinical applications and mechanisms of action of S. barbata have been investigated, many constituents remain unknown. Further investigations are required to investigate the medicinal properties of S. barbata.

Cultivated Fruit Body of Phellinus baumii: A Potentially Sustainable Antidiabetic Resource

Previous studies have been reported that the fruit body of wild Phellinus baumii alleviates diabetes, and antioxidants are beneficial to diabetes by protecting the β-cell from damage due to oxidative stress. Large-scale cultivation of P. baumii fruit body has been successful in the past decade. This paper aimed to investigate whether the fruit body of the cultivated P. baumii has the same analogical effects as the wild. The cultivated P. baumii fruit body was extracted by 80% of ethanol extracts, and different fractions were obtained with the successive use of petroleum ether, ethyl acetate (EtOAc), n-butanol (n-BuOH), and water, which yielded 15.98 ± 1.56, 1.74 ± 0.34, 3.31 ± 0.41, 4.12 ± 0.37, and 1.38 ± 0.26% extract recovery, respectively. Results show that the EtOAc fraction exhibits the highest inhibitory effect on α-glucosidase activity (IC50 = 49.05 ± 3.14 μg mL-1), which is an order of magnitude higher than the positive control (acarbose, IC50 = 645.73 ± 7.86 μg mL-1). It was mainly composed of phenolic compounds with a purity of 79.45% and characterized by liquid chromatography-mass spectrometry as osmudacetone, hispidin, davallialactone, 2,5-bis(4,7-dihydroxy-8-methyl-2-oxo-2H-chromen-3-yl)cyclohexa-2,5-diene-1,4-dione, hypholomin B, and inoscavin A. Furthermore, the EtOAc fraction increased the glucose consumption of insulin-resistant HepG2 cells at a concentration range of 25-100 μg mL-1. The EtOAc fraction also demonstrated antioxidant activities by scavenging 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt, and hydroxyl radicals. In conclusion, the EtOAc fraction of the cultivated P. baumii fruit body exerted effective antidiabetic effects, possibly due to the high content of selective phenolic compounds. Hence, the cultivated fruit body of P. baumii can be a sustainable resource for treating diabetes, and our work also shed some light on its future utilization.

Phytotoxic neo-clerodane diterpenoids from the aerial parts of Scutellaria barbata

Bioactivity guided the isolation of extracts from the aerial parts Scutellaria barbata D. Don to discover neo-clerodane diterpenoids with potent phytotoxic activity. Of the 34 isolates, 13 neo-clerodane diterpenoids were described for the first time. The structures of these undescribed compounds were elucidated by extensive analysis of NMR spectroscopic data, and the absolute configurations of scutebarbolides A and L and scutebata W were determined by X-ray diffraction. The phytotoxic activity of all compounds against the growth of the roots and shoots of L. perenne and L. sativa seedlings were first reported, and some compounds showed considerable inhibitory effects, especially scutebarbolide K, whose inhibition rates were higher than those of the positive control at concentrations ranging from 25 to 200 μg/mL. When L. perenne and L. sativa seedlings were treated at a concentration of 200 μg/mL, scutebarbolide K caused wilting symptoms on and finally death of these two tested plant seedlings. In addition, the structure-activity relationships of these neo-clerodane diterpenoids were also discussed.

Flavonoid aglycone-oriented data-mining in high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry: efficient and targeted profiling of flavonoids in Scutellaria barbata

The high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) technique is a powerful tool for compound identification in complex natural products. However, untargeted MS/MS data analysis needs skillful experience and sometimes neglects minor compounds, which are co-eluted with major ones or overshadowed by the matrix. Flavonoids are the main bioactive components in Scutellaria barbata, and the total flavonoid content is 47.02 ± 3.23 mg QE/g DW. Although some flavonoid aglycones and their O-glycosides have been found in S. barbata, comprehensive profiling of flavonoids is unknown. Therefore, we report a flavonoid aglycone-oriented data-mining strategy for efficient and targeted profiling of flavonoids in S. barbata. The strategy includes four steps: (1) HPLC-QTOF-MS analysis of S. barbata; (2) construction of a flavonoid aglycone-based database according to biosynthetic pathway analysis and reported data; (3) extraction of through flavonoid aglycone-based ion chromatography; (4) identification of targeted flavonoids by MS/MS analysis. As a result, 45 flavonoids, including 24 flavones, 1 flavonol, 13 flavanones, and 7 flavanonols, were unambiguously or tentatively identified, while 20 of them were reported in S. barbata for the first time. Moreover, 14 available flavonoids were sensitively, precisely, and accurately determined by standard calibration curves, with limit of detection at 0.06 to 1.55 μg/g, limit of quantification at 0.16 to 3.70 μg/g, relative standard deviation (RSD) less than 9.0% for intra- and inter-day variations, and recovery at 92.6-108.1%. The matrix did not obviously suppress or enhance the ionization of 14 flavonoids, and finally their contents ranging from 0.04 to 4.49 mg/g in S. barbata were successfully achieved. Collectively, our results demonstrate that an efficient, reliable, and valuable strategy has been provided to rapidly and sensitively screen, profile, and quantify chemical components of complex natural products. Graphical abstract.

Alkaloids from Piper nigrum Synergistically Enhanced the Effect of Paclitaxel against Paclitaxel-Resistant Cervical Cancer Cells through the Downregulation of Mcl-1

In the current study, nine amide alkaloids, including two new dimeric amides and a new natural product, were identified from Piper nigrum. Among them, seven compounds sensitized paclitaxel-resistant cervical cancer cells HeLa/PTX to paclitaxel. Piperine was a major component obtained from Piper nigrum, and its sensitization mechanism was investigated. Combination treatment enhanced cell apoptosis, which was mediated by downregulation of phospho-Akt and Mcl-1. Piperine (50 μM) combined with paclitaxel (200 nM) downregulated Mcl-1 protein expression with a decrease of 35.9 ± 9.5% ( P < 0.05). Moreover, overexpression of Mcl-1 attenuated the inhibitory effect of this combination. Furthermore, combination treatments of six dimeric amide alkaloids and paclitaxel all downregulated Mcl-1 protein expression with a decrease ranging from 23.5 ± 9.7% to 41.7 ± 7.2% ( P < 0.05). We reveal, for the first time, that dimeric amide alkaloids from plants possess a remarkable sensitization effect on cancer cells to paclitaxel.

Quercetin and Sodium Butyrate Synergistically Increase Apoptosis in Rat C6 and Human T98G Glioblastoma Cells Through Inhibition of Autophagy

This study investigated the efficacy of quercetin (QCT) in combination with sodium butyrate (NaB) in enhancing apoptosis in rat C6 and human T98G glioblastoma cells though blockage of autophagy under nutrient-starvation. The most synergistic doses of the drugs were determined to be 25 µM QCT and 1 mM NaB in both cell lines. After QCT and QCT + NaB treatments, autophagy quantification with acridine orange staining showed a drastic decrease in protective autophagy in the cells under nutrient-starvation. Decrease in autophagy was correlated with decreases in expression of Beclin-1 and LC3B II. Combination treatment increased the morphological signs of apoptosis including membrane blebbing, nuclear fragmentation, and chromatin condensation. Annexin V staining was also performed for detection and quantification of increases in apoptosis. Western blotting results showed that combination of QCT and NaB increased apoptosis by decreasing anti-apoptotic Bcl-2 and increasing pro-apoptotic Bax, decreasing survivin, activating caspase-3, and degrading poly (ADP-ribose) polymerase (PARP). This study demonstrated the therapeutic potentials of a novel combination therapy in inhibiting protective autophagy to enhance apoptosis in rat C6 and human T98G glioblastoma cells.

Neoclerodane diterpenoids from Scutellaria barbata with cytotoxic activities

Two new neoclerodane diterpenoids, barbatin F (1), barbatin G (2) together with four known compounds, scutebata A (3), scutebata B (4), scutebata C (5) and scutebata P (6) were isolated from the whole plant of Scutellaria barbata D.Don. Their structures were elucidated on the basis of spectroscopic studies. In vitro cytotoxicity of selected compounds against cancer cell lines LoVo, SMMC-7721, HCT-116, and MCF-7 were evaluated, compound 1 and 2 showed weak cytotoxic activities against HCT-116 colon cancer cell lines with IC₅₀ value of 44.3, 32.3 μM, respectively, while compound 3 and 4 exhibited moderate cytotoxic activities against four tested human cancer cell lines with IC₅₀ values of 5.31～28.5 μM.

In vitro study on reversal of ovarian cancer cell resistance to cisplatin by naringin via the nuclear factor-κB signaling pathway

The aim of the present study was to investigate the mechanism of action by which naringin reverses the resistance of ovarian cancer cells to cisplatin. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and western blotting assays were used to detect the effects of different concentrations of naringin on the expressions of nuclear factor (NF)-κB and P-glycoprotein (P-gp) in the SKOV3/CDDP cell line. Small interfering RNA (siRNA) targeting NF-κB was designed and synthesized to silence NF-κB, and recombinant plasmid vectors overexpressing NF-κB were constructed to transfect cells. RT-qPCR and western blotting assays were subsequently performed to detect the effects of NF-κB on the expression of P-gp at the mRNA and protein levels. Naringin was added to the NF-κB-overexpressing SKOV3/CDDP cells and cultured for 48 h, followed by the detection of the expression of P-gp. RT-PCR and western blotting results demonstrated that the gene and protein expressions of NF-κB and P-gp were significantly decreased in a dose-dependent manner by naringin treatment (P<0.05). In cells overexpressing NF-κB, P-gp expression was significantly elevated (P<0.05), and the expression of P-gp was significantly decreased when NF-κB was silenced (P<0.05). Treatment with naringin was able to significantly ameliorate the NF-κB-induced overexpression of P-gp (P<0.05). These results indicate that naringin is able to inhibit the expression of NF-κB and P-gp in SKOV3/CDDP cells. Such an inhibitory effect may increase gradually with concentration, and is associated with blockade of the NF-κB signaling pathway. This pathway may represent one of the mechanisms of action by which Naringin reverses resistance to platinum-based agents in ovarian cancer cells.