α-Chaconine and α-Solanine Inhibit RL95-2 Endometrium Cancer Cell Proliferation by Reducing Expression of Akt (Ser473) and ERα (Ser167)

Effects of α‑solanine on human head and neck squamous cell carcinoma cells and human umbilical vein endothelial cells in vitro

α-solanine is a glycoalkaloid that is commonly found in nightshades (Solanum) and has a toxic effect on the human organism. Among other things, it is already known to inhibit tumor cell proliferation and induce apoptosis in tumor cell lines. Due to its potential as a tumor therapeutic, the current study investigated the effect of α-solanine on head and neck squamous cell carcinoma (HNSCC). In addition, genotoxic and antiangiogenic effects on human umbilical vein endothelial cells (HUVECs) were evaluated at subtoxic α-solanine concentrations. Cytotoxicity and apoptosis rates were measured in two human HNSCC cell lines (FaDu pharynx carcinoma cells and CAL-33 tongue carcinoma cells), as well as in HUVECs. MTT and Annexin V analyses were performed 24 h after α-solanine treatment at increasing doses up to 30 µM to determine cytotoxic concentrations. Furthermore, genotoxicity at subtoxic concentrations of 1, 2, 4 and 6 µM in HUVECs was analyzed using single-cell gel electrophoresis (comet assay). The antiangiogenic effect on HUVECs was evaluated in the capillary tube formation assay. The MTT assay indicated an induction of concentration-dependent viability loss in FaDu and CAL-33 cancer cell lines, whereas the Annexin V test revealed α-solanine-induced cell death predominantly independent from apoptosis. In HUVECs, the cytotoxic effect occurred at lower concentrations. No genotoxicity or inhibition of angiogenesis were detected at subtoxic doses in HUVECs. In summary, α-solanine had a cytotoxic effect on both malignant and non-malignant cells, but this was only observed at higher concentrations in malignant cells. In contrast to existing data in the literature, tumor cell apoptosis was less evident than necrosis. The lack of genotoxicity and antiangiogenic effects in the subtoxic range in benign cells are promising, as this is favorable for potential therapeutic applications. In conclusion, however, the cytotoxicity in non-malignant cells remains a severe hindrance for the application of α-solanine as a therapeutic tumor agent in humans.

Advances in antitumor activity and mechanism of natural steroidal saponins: A review of advances, challenges, and future prospects

BACKGROUND

Cancer, the second leading cause of death worldwide following cardiovascular diseases, presents a formidable challenge in clinical settings due to the extensive toxic side effects associated with primary chemotherapy drugs employed for cancer treatment. Furthermore, the emergence of drug resistance against specific chemotherapeutic agents has further complicated the situation. Consequently, there exists an urgent imperative to investigate novel anticancer drugs. Steroidal saponins, a class of natural compounds, have demonstrated notable antitumor efficacy. Nonetheless, their translation into clinical applications has remained unrealized thus far. In light of this, we conducted a comprehensive systematic review elucidating the antitumor activity, underlying mechanisms, and inherent limitations of steroidal saponins. Additionally, we propose a series of strategic approaches and recommendations to augment the antitumor potential of steroidal saponin compounds, thereby offering prospective insights for their eventual clinical implementation.

PURPOSE

This review summarizes steroidal saponins' antitumor activity, mechanisms, and limitations.

METHODS

The data included in this review are sourced from authoritative databases such as PubMed, Web of Science, ScienceDirect, and others.

RESULTS

A comprehensive summary of over 40 steroidal saponin compounds with proven antitumor activity, including their applicable tumor types and structural characteristics, has been compiled. These steroidal saponins can be primarily classified into five categories: spirostanol, isospirostanol, furostanol, steroidal alkaloids, and cholestanol. The isospirostanol and cholestanol saponins are found to have more potent antitumor activity. The primary antitumor mechanisms of these saponins include tumor cell apoptosis, autophagy induction, inhibition of tumor migration, overcoming drug resistance, and cell cycle arrest. However, steroidal saponins have limitations, such as higher cytotoxicity and lower bioavailability. Furthermore, strategies to address these drawbacks have been proposed.

CONCLUSION

In summary, isospirostanol and cholestanol steroidal saponins demonstrate notable antitumor activity and different structural categories of steroidal saponins exhibit variations in their antitumor signaling pathways. However, the clinical application of steroidal saponins in cancer treatment still faces limitations, and further research and development are necessary to advance their potential in tumor therapy.

α-Solanine attenuates chondrocyte pyroptosis to improve osteoarthritis via suppressing NF-κB pathway

α-Solanine has been shown to exhibit anti-inflammatory and anti-tumour properties; however, its efficacy in treating osteoarthritis (OA) remains ambiguous. The study aimed to evaluate the therapeutic effects of α-solanine on OA development in a mouse OA model. The OA mice were subjected to varying concentrations of α-solanine, and various assessments were implemented to assess OA progression. We found that α-solanine significantly reduced osteophyte formation, subchondral sclerosis and OARSI score. And it decreased proteoglycan loss and calcification in articular cartilage. Specifically, α-solanine inhibited extracellular matrix degradation by downregulating collagen 10, matrix metalloproteinase 3 and 13, and upregulating collagen 2. Importantly, α-solanine reversed chondrocyte pyroptosis phenotype in articular cartilage of OA mice by inhibiting the elevated expressions of Caspase-1, Gsdmd and IL-1β, while also mitigating aberrant angiogenesis and sensory innervation in subchondral bone. Mechanistically, α-solanine notably hindered the early stages of OA progression by reducing I-κB phosphorylation and nuclear translocation of p65, thereby inactivating NF-κB signalling. Our findings demonstrate the capability of α-solanine to disrupt chondrocyte pyroptosis and sensory innervation, thereby improving osteoarthritic pathological progress by inhibiting NF-κB signalling. These results suggest that α-solanine could serve as a promising therapeutic agent for OA treatment.

Roles of estrogen receptor α in endometrial carcinoma (Review)

Endometrial carcinoma (EC) is a group of endometrial epithelial malignancies, most of which are adenocarcinomas and occur in perimenopausal and postmenopausal women. It is one of the most common carcinomas of the female reproductive system. It has been shown that the occurrence and development of EC is closely associated with the interaction between estrogen (estradiol, E2) and estrogen receptors (ERs), particularly ERα. As a key nuclear transcription factor, ERα is a carcinogenic factor in EC. Its interactions with upstream and downstream effectors and co-regulators have important implications for the proliferation, metastasis, invasion and inhibition of apoptosis of EC. In the present review, the structure of ERα and the regulation of ERα in multiple dimensions are described. In addition, the classical E2/ERα signaling pathway and the crosstalk between ERα and other EC regulators are elucidated, as well as the therapeutic targeting of ERα, which may provide a new direction for clinical applications of ERα in the future.

Antioxidants Amelioration Is Insufficient to Prevent Acrylamide and Alpha-Solanine Synergistic Toxicity in BEAS-2B Cells

Cells produce free radicals and antioxidants when exposed to toxic compounds during cellular metabolism. However, free radicals are deleterious to lipids, proteins, and nucleic acids. Antioxidants neutralize and eliminate free radicals from cells, preventing cell damage. Therefore, the study aims to determine whether the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) will ameliorate the maximum dose of acrylamide and alpha (α)-solanine synergistic toxic effects in exposed BEAS-2B cells. These toxic compounds are consumed worldwide by eating potato products. BEAS-2B cells were simultaneously treated with BHA 10 μM and BHT 20 μM and incubated in a 5% CO2 humidified incubator for 24 h, followed by individual or combined treatment with acrylamide (3.5 mM) and α-solanine (44 mM) for 48 h, including the controls. Cell morphology, DNA, RNA, and protein were analyzed. The antioxidants did not prevent acrylamide and α-solanine synergistic effects in exposed BEAS-2B cells. However, cell morphology was altered; polymerase chain reaction (PCR) showed reduced RNA constituents but not DNA. In addition, the toxic compounds synergistically inhibited AKT/PKB expression and its downstream genes. The study showed BHA and BHT are not protective against the synergetic toxic effects of acrylamide and α-solanine in exposed BEAS-2B cells.

The Therapeutic Value of Solanum Steroidal (Glyco)Alkaloids: A 10-Year Comprehensive Review

Steroidal (glycol)alkaloids S(G)As are secondary metabolites made of a nitrogen-containing steroidal skeleton linked to a (poly)saccharide, naturally occurring in the members of the Solanaceae and Liliaceae plant families. The genus Solanum is familiar to all of us as a food source (tomato, potato, eggplant), but a few populations have also made it part of their ethnobotany for their medicinal properties. The recent development of the isolation, purification and analysis techniques have shed light on the structural diversity among the SGAs family, thus attracting scientists to investigate their various pharmacological properties. This review aims to overview the recent literature (2012-2022) on the pharmacological benefits displayed by the SGAs family. Over 17 different potential therapeutic applications (antibiotic, antiviral, anti-inflammatory, etc.) were reported over the past ten years, and this unique review analyzes each pharmacological effect independently without discrimination of either the SGA's chemical identity or their sources. A strong emphasis is placed on the discovery of their biological targets and the subsequent cellular mechanisms, discussing in vitro to in vivo biological data. The therapeutic value and the challenges of the solanum steroidal glycoalkaloid family is debated to provide new insights for future research towards clinical development.

Anticancer activity of glycoalkaloids from Solanum plants: A review

Cancer is still one of the main causes of death worldwide. For this reason, new compounds that have chemotherapeutic potential have been identified. One such group of substances is Solanaceae glycoalkaloids (GAs). They are natural compounds produced by plants widely used in traditional medicine for healing many disorders. Among others, GAs exhibit significant antitumor properties, for example, a strong inhibitory effect on cancer cell growth. This activity can result in the induction of tumor cell apoptosis, which can occur via different molecular pathways. The molecular mechanisms of the action of GAs are the subject of intensive research, as improved understanding could lead to the development of new cancer therapies. The genetic basis for the formation of neoplasms are mutations in protooncogenes, suppressors, and apoptosis-controlling and repair genes; therefore, substances with antineoplastic properties may affect the levels of their expression or the levels of their expression products. Therapeutic compounds can be applied separately or in combination with other drugs to increase the efficiency of cancer therapy; they can act on the cell through various mechanisms at different stages of carcinogenesis, inducing the process of apoptosis, blocking cell proliferation and migration, and inhibiting angiogenesis. This review summarizes the newest studies on the anticancer properties of solanine (SN), chaconine (CH), solasonine (SS), solamargine (SM), tomatine (TT) and their extracts from Solanum plants.

Natural Products in Preventing Tumor Drug Resistance and Related Signaling Pathways

Drug resistance is still an obstacle in cancer therapy, leading to the failure of tumor treatment. The emergence of tumor drug resistance has always been a main concern of oncologists. Therefore, overcoming tumor drug resistance and looking for new strategies for tumor treatment is a major focus in the field of tumor research. Natural products serve as effective substances against drug resistance because of their diverse chemical structures and pharmacological effects. We reviewed the signaling pathways involved in the development of tumor drug resistance, including Epidermal growth factor receptor (EGFR), Renin-angiotensin system (Ras), Phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), Wnt, Notch, Transforming growth factor-beta (TGF-β), and their specific signaling pathway inhibitors derived from natural products. This can provide new ideas for the prevention of drug resistance in cancer therapy.

Solasonine induces apoptosis of the SGC-7901 human gastric cancer cell line in vitro via the mitochondria-mediated pathway

Solasonine, a steroidal glycoalkaloid isolated from the herbal plant Solanum nigrum Linn., has shown active against multiple human cancers; however, there is little knowledge on the activity of solasonine against gastric cancer until now. This study aimed to examine the effect of solasonine on the biological behaviours of human gastric cancer SGC‐7901 cells. The results showed that solasonine suppressed SGC‐7901 cell proliferation in a dose‐dependent manner. Solasonine treatment mainly induced the cell cycle arrest at G2 phase in SGC‐7901 cells. Treatment with solasonine resulted in significant down‐regulation of Bcl‐2 and Caspase‐3 protein expression and reduced Bax and Bcl‐xL protein expression in SGC‐7901 cells. Solasonine shows a comparable inhibitory effect on the proliferation of human gastric cancer SGC‐7901 cells with cisplatin, and solasonine induces of SGC‐7901 cell apoptosis through triggering the endoplasmic reticulum stress pathway and the mitochondrial pathway. Our data indicate that solasonine may be a promising agent for the treatment of gastric cancer.

Hidden in Plants-A Review of the Anticancer Potential of the Solanaceae Family in In Vitro and In Vivo Studies

Many of the anticancer agents that are currently in use demonstrate severe side effects and encounter increasing resistance from the target cancer cells. Thus, despite significant advances in cancer therapy in recent decades, there is still a need to discover and develop new, alternative anticancer agents. The plant kingdom contains a range of phytochemicals that play important roles in the prevention and treatment of many diseases. The Solanaceae family is widely used in the treatment of various diseases, including cancer, due to its bioactive ingredient content. The purpose of this literature review is to highlight the antitumour activity of Solanaceae extracts-single isolated compounds and nanoparticles with extracts-and their synergistic effect with chemotherapeutic agents in various in vitro and in vivo cancer models. In addition, the biological properties of many plants of the Solanaceae family have not yet been investigated, which represents a challenge and an opportunity for future anticancer therapy.

Synergistic Growth Inhibitory Effects of Eryngium kotschyi Extracts with Conventional Cytotoxic Agents: Cisplatin and Doxorubicin Against Human Endometrium Cancer Cells

BACKGROUND

Endometrial cancer is one of the most common types of cancer. For this reason, various studies have been carried out on its treatment and the effects of natural products on this disease.

OBJECTIVE

This study aimed to examine the growth inhibitory effects of Eryngium kotschyi Boiss. ethyl acetate [EKE] and butanol [EKB] obtained from the main methanol [EKM] extract from the aerial parts on human endometrium carcinoma [RL95-2] cells and their synergistic effect with cisplatin or doxorubicin.

METHODS

RL95-2 cells were treated with E. kotschyi extracts either alone or in combination with cisplatin or doxorubicin. The effects on cell growth were determined using the MTT assay and real-time cell analysis xCELLigence.

RESULTS

The extracts demonstrated growth inhibitory activity, with a certain degree of selectivity against the RL95-2 cell line. Synergistic effects of EKE/cisplatin or doxorubicin at different concentration levels were demonstrated in RL95-2 cells. In some instances, the EKE/doxorubicin combinations resulted in antagonistic effects. The reduction level of cell viability was different and specific to each combination for the RL95-2 cell line.

CONCLUSION

The growth inhibitory activity of cisplatin or doxorubicin, as a single agent, may be modified by combinations of the extracts and be synergistically enhanced in some cases. A significant synergistic effect of EKE on the RL95-2 cell line with cisplatin and doxorubicin was observed. This cytotoxic effect can be investigated in terms of molecular mechanisms. This study is the first of its kind in the literature. The mechanisms involved in this interaction between chemotherapeutic drugs and plant extracts remain unclear and should be further evaluated.

GSI Treatment Preserves Protein Synthesis in C2C12 Myotubes

It has been demonstrated that inhibiting Notch signaling through γ-secretase inhibitor (GSI) treatment increases myogenesis, AKT/mTOR signaling, and muscle protein synthesis (MPS) in C2C12 myotubes. The purpose of this study was to determine if GSI-mediated effects on myogenesis and MPS are dependent on AKT/mTOR signaling. C2C12 cells were assessed for indices of myotube formation, anabolic signaling, and MPS following GSI treatment in combination with rapamycin and API-1, inhibitors of mTOR and AKT, respectively. GSI treatment increased several indices of myotube fusion and MPS in C2C12 myotubes. GSI-mediated effects on myotube formation and fusion were completely negated by treatment with rapamycin and API-1. Meanwhile, GSI treatment was able to rescue MPS in C2C12 myotubes exposed to rapamycin or rapamycin combined with API-1. Examination of protein expression revealed that GSI treatment was able to rescue pGSK3β Ser9 despite AKT inhibition by API-1. These findings demonstrate that GSI treatment is able to rescue MPS independent of AKT/mTOR signaling, possibly via GSK3β modulation.

Prediction of α-Solanine and α-Chaconine in Potato Tubers from Hunter Color Values and VIS/NIR Spectra

The glycoalkaloids contents of potato tubers are usually measured by the destructive analysis that consumes time and requires expensive high-performance equipment. This study was carried out to determine the possibility of nondestructive estimation of α-solanine and α-chaconine content in potato tubers. Visible/near-infrared (VIS/NIR) spectra, color values, and the reference α-solanine and α-chaconine were measured from 180 tubers of ‘Atlantic’ and ‘Trent’ potato cultivars with eight replications at two-week intervals during the storage up to ten weeks. The partial least square (PLS) regression method was used to develop models correlating color and spectra data to the measured reference data. Regression coefficient (r) between color variables (Hunter $a^{\ast }$ , ${\text{a}}^{\ast }/{\text{b}}^{\ast }$ , and ( ${\text{a}}^{\ast }/{\text{b}}^{\ast }$ )2) and the actual measured values of a-solanine and a-chaconine content were 0.74, 0.62, and 0.62 and 0.70, 0.58, and 0.57, respectively, for the prediction set. Concurrently, equations were developed from color variables in multiple regression with r-values of 0.76 and 0.71 for α-solanine and α-chaconine, respectively. Additionally, the selected PLS model of VIS/NIR spectra had promising predictive power for α-solanine and α-chaconine with r-values of 0.68 and 0.63, respectively, between measured and predicted samples. Taken together, although it requires further studies to improve the prediction power of the developed models, the results of this study revealed the possibility of using VIS/NIR spectra and color variables for the prediction of α-solanine and α-chaconine contents from intact unpeeled potato tubers with chemical-free, fast, and cheap assessment methods.

Wnt/PCP signalling cascade disruption by JNK inhibition as a potential mechanism underlying the teratogenic effects of potato glycoalkaloids

It is hypothesised that the inhibition of the non-canonical Wnt/PCP intracellular signalling cascade by potato glycoalkaloids, [Formula: see text]-solanine and [Formula: see text]-chaconine, results in an increased risk of neural tube defects (NTDs). One very prominent intracellular signalling pathway with substantial implications in the development and closure of the neural tube is the Wnt/PCP pathway. Experimental inhibition of this results in NTDs. A vital element of this signalling cascade is JNK, which controls the transcription of DNA, which controls cell polarity and directional cell migration. JNK inhibition also results in NTDs experimentally. Through their use in cancer research, [Formula: see text]-solanine and [Formula: see text]-chaconine were found to inhibit metastasis by inhibiting JNK, among other intracellular signalling molecules. Thus, this shows that potato glycoalkaloids increase the likelihood of causing NTDs by inhibiting the proper functioning of JNK in the Wnt/PCP pathway, resulting in defective neural tube closure.

Real-time cell analysis system in cytotoxicity applications: Usefulness and comparison with tetrazolium salt assays

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RTCA system allows to easily monitor cell adhesion and proliferation.

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The real-time impedance technique is widely used in many toxicological studies.

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RTCA results are generally comparable with results from tetrazolium salts assays.

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RTCA analysis should be limited when drugs with electroactive additives are tested.

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Tetrazolium salts assays should be avoided when colored compounds are studied.

Real-time cell analysis (RTCA) is a technique based on impedance and microsensor electrodes. RTCA system allows label-free, real-time, and continuous monitoring of cell adhesion, morphology, and rate of cell proliferation. The system offers a wide range of applications, mainly in toxicological studies, new drug screening, and microbiology. Here, we describe the usefulness of the system in different applications and compare this technology with conventional endpoint assays based on tetrazolium salts. We present advantages and disadvantages of the system and endpoint methods and their limitations in cytotoxicity investigations.