Triptonide inhibits lung cancer cell tumorigenicity by selectively attenuating the Shh-Gli1 signaling pathway

Triptonide induces apoptosis and inhibits the proliferation of ovarian cancer cells by activating the p38/p53 pathway and autophagy

Ovarian cancer is a common malignant tumor in women, and 70 % of ovarian cancer patients are diagnosed at an advanced stage. Drug chemotherapy is an important method for treating ovarian cancer, but recurrence and chemotherapy resistance often lead to treatment failure. In this study, we screened 10 extracts of Tripterygium wilfordii, a traditional Chinese herb, and found that triptonide had potent anti-ovarian cancer activity and an IC50 of only 3.803 nM against A2780 cell lines. In addition, we determined that triptonide had a better antitumor effect on A2780 cell lines than platinum chemotherapeutic agents in vitro and that triptonide had no significant side effects in vivo. We found that triptonide induced apoptosis in ovarian cancer cells through activation of the p38/p53 pathway and it also induced cell cycle arrest at the S phase. In addition, we demonstrated that triptonide could activate lethal autophagy, which led to growth inhibition and cell death in ovarian cancer cells, resulting in an anti-ovarian cancer effect. Triptonide exerts its anti-ovarian cancer effect through activation of the p38/p53 pathway and induction of autophagy to promote apoptosis, which provides a new candidate drug and strategy for the treatment of ovarian cancer.

A novel antitumor mechanism of triptonide in colorectal cancer: inducing ferroptosis via the SLC7A11/GPX4 axis

Colorectal cancer (CRC) is a prevalent malignancy affecting the human digestive tract. Triptonide has been shown to have some anticancer activity, but its effect in CRC is vague. Herein, we examined the effect of triptonide on CRC. In this study, the results of bioinformatics analysis displayed that triptonide may regulate ferroptosis in CRC by modulating GPX4 and SLC7A11. In HCT116 and LoVo cells, the expression levels of GPX4 and SLC7A11 were significantly reduced after triptonide management versus the control group. Triptonide inhibited proliferation, but promoted ferroptosis in CRC cells. SLC7A11 upregulation overturned the effects of triptonide on proliferation and ferroptosis in CRC cells. Triptonide inhibited activation of the PI3K/AKT/Nrf2 signaling in CRC cells. Activation of the PI3K/AKT signaling or Nrf2 upregulation overturned the effects of triptonide on proliferation and ferroptosis in CRC cells. Triptonide suppressed CRC cell growth in vivo by modulating SLC7A11 and GPX4. In conclusion, Triptonide repressed proliferation and facilitated ferroptosis of CRC cells by repressing the SLC7A11/GPX4 axis through inactivation of the PI3K/AKT/Nrf2 signaling.

Telomerase Inhibition in the Treatment of Leukemia: A Comprehensive Review

Leukemia, characterized by the uncontrolled proliferation and differentiation blockage of myeloid or lymphoid precursor cells, presents significant therapeutic challenges despite current treatment modalities like chemotherapy and stem cell transplantation. Pursuing novel therapeutic strategies that selectively target leukemic cells is critical for improving patient outcomes. Natural products offer a promising avenue for developing effective chemotherapy and preventive measures against leukemia, providing a rich source of biologically active compounds. Telomerase, a key enzyme involved in chromosome stabilization and mainly active in cancer cells, presents an attractive target for intervention. In this review article, we focus on the anti-leukemic potential of natural substances, emphasizing vitamins (such as A, D, and E) and polyphenols (including curcumin and indole-3-carbinol), which, in combination with telomerase inhibition, demonstrate reduced cytotoxicity compared to conventional chemotherapies. We discuss the role of human telomerase reverse transcriptase (hTERT), particularly its mRNA expression, as a potential therapeutic target, highlighting the promise of natural compounds in leukemia treatment and prevention.

Lycorine inhibits pancreatic cancer cell growth and neovascularization by inducing Notch1 degradation and downregulating key vasculogenic genes

Pancreatic cancer is highly metastatic and lethal with an increasing incidence globally and a 5-year survival rate of only 8%. One of the factors contributing to the high mortality is the lack of effective drugs in the clinical setting. We speculated that effective compounds against pancreatic cancer exist in natural herbs and explored active small molecules among traditional Chinese medicinal herbs. The small molecule lycorine (MW: 323.77) derived from the herb Lycoris radiata inhibited pancreatic cancer cell growth with an IC50 value of 1 μM in a concentration-dependent manner. Lycorine markedly reduced pancreatic cancer cell viability, migration, invasion, neovascularization, and gemcitabine resistance. Additionally, lycorine effectively suppressed tumor growth in mouse xenograft models without obvious toxicity. Pharmacological studies revealed that the levels and half-life of Notch1 oncoprotein in the pancreatic cancer cells Panc-1 and Patu8988 were notably reduced. Moreover, the expression of the key vasculogenic genes Semaphorin 4D (Sema4D) and angiopoietin-2 (Ang-2) were also significantly inhibited by lycorine. Mechanistically, lycorine strongly triggered the degradation of Notch1 oncoprotein through the ubiquitin-proteasome system. In conclusion, lycorine effectively inhibits pancreatic cancer cell growth, migration, invasion, neovascularization, and gemcitabine resistance by inducing degradation of Notch1 oncoprotein and downregulating the key vasculogenic genes Sema4D and Ang-2. Our findings provide a new therapeutic candidate and treatment strategy against pancreatic cancer.

Triptonide Ameliorates Middle Cerebral Artery Occlusion-induced Cerebral Ischemic Damage in Rats via Regulation of In flammatory Response

Background

Cerebral ischemic stroke is the second major cause of mortality worldwide that results in persisting disability and mental agony. Ischemic stroke is induced by the diminished blood circulation to the brain, which can be due to obstruction by arteriosclerosis, fibromuscular dysplasia, or thrombosis. Triptonide is a diterpene triepoxide, purified out of extracts of Tripterygium wilfordii Hook F, and is an emerging target against, for example, cancers and inflammatory insults.

Materials and Methods

Taking this into consideration, this study was designed to analyze the effect of triptonide on ischemic/reperfusion (I/R) cerebral infarction stroke rats.

Results

Our study showed that triptonide decreased the infarct volume and brain edema produced by I/R. Moreover, triptonide protected the rats from any neurological deficits, which were analyzed using a five-point scoring system, augmented antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione content, and lowered the activity of acetylcholinesterase. Triptonide also decreased the levels of pro-inflammatory cytokines such as interleukin-1 β (IL-1 β), TNF- α, and IL-6, while it augmented anti-inflammatory cytokines IL-10 and vascular endothelial growth factor. In this study, cerebral infarction stroke rats showed an increase in malondialdehyde levels. Triptonide preserved the normal brain architecture from various neurotoxic effects.

Conclusion

Thus, triptonide can be targeted for drug discovery in the future to protect against cerebral infarction stroke.

Triptonide, a Diterpenoid Displayed Anti-Inflammation, Antinociceptive, and Anti-Asthmatic Efficacy in Ovalbumin-Induced Mouse Model

The present study was intended to explore the valuable effects of triptonide on inflammation, asthmatic, and nociceptive. Triptonide possesses numerous beneficial effects extensively managed in the treatment of inflammation disease condition. Initially, triptonide showed anti-inflammation properties over lipopolysaccharide-induced RAW 264.7 cells. Hence, the present study was directed to explore the protecting efficacy of triptonide in ovalbumin (OVA)-induced asthma in mice. Asthma was induced intraperitoneally administration (200μL) in female BALB/c mice with suspension which has ovalbumin (100 μg/mL) and aluminum hydroxide (10 mg/mL). Triptonide (30 mg/kg) over OVA-induced experimental animals altered lung mass, nitric oxide, myeloperoxidase, immunoglobulin E status, interleukins (4, 5, and 13) inflammatory cytokines status, and histological modifications. Animals were also managed with the standard drug dexamethasone (50 mg/kg) followed by the asthma induction, which is also efficient over OVA-induced experimental animals. The nociception was provoked in male Swiss mice by various chemicals (acetic acid, capsaicin, and glutamate). The animals were administered with triptonide (5, 10, and 15 mg/kg) and separate standard drugs like diclofenac sodium (10 mg/kg) and morphine (5 mg/kg) over chemical-induced nociceptive animals. The present outcome evidently established that the triptonide considerably reduced the various chemical-induced nociception in mice (Fig. 7A, B, and C). Ultimately, the present work explored the evident powerful anti-inflammation, antinociceptive, and anti-asthma properties of a diterpenoid, triptonide experimental animal models. And it is recommended that triptonide is an excellent compound in the management of asthma and its related diseases.

Triptonide Inhibits the Cervical Cancer Cell Growth via Downregulating the RTKs and Inactivating the Akt-mTOR Pathway

The high incidence and mortality of cervical cancer (CC) require an urgent need for exploring novel valuable therapeutics. Triptonide (TN) is a small molecule monomer extracted from the Chinese herb Tripterygium wilfordii Hook. Our results showed that TN, at only nanomolar concentrations, strongly inhibited growth, colony formation, proliferation, migration, and invasion of established and primary human cervical cancer cells. TN induced apoptosis and cell cycle arrest in cervical cancer cells. Moreover, cervical cancer cell in vitro migration and invasion were suppressed by TN. It was however noncytotoxic and proapoptotic to normal cervical epithelial cells and human skin fibroblast cells. Gene set enrichment analysis (GSEA) of RNA sequencing data of differentially expressed genes (DEGs) in TN-treated cervical cancer cells implied that DEGs were enriched in the receptor tyrosine kinase (RTK) signaling and PI3K-Akt-mTOR cascade. In cervical cancer cells, RTKs, including EGFR and PDGFRα, were significantly downregulated and Akt-mTOR activation was largely inhibited after TN treatment. In vivo, oral administration of TN significantly inhibited subcutaneous cervical cancer xenograft growth in nude mice. EGFR and PDGFRα downregulation as well as Akt-mTOR inactivation was detected in TN-treated HeLa xenograft tumor tissues. Thus, TN inhibits human cervical cancer cell growth in vitro and in vivo. Its anticervical cancer activity was associated with RTK downregulation and Akt-mTOR inactivation.

Molecular Mechanisms Involving the Sonic Hedgehog Pathway in Lung Cancer Therapy: Recent Advances

According to the latest statistics from the International Agency for Research on Cancer (IARC), lung cancer is one of the most lethal malignancies in the world, accounting for approximately 18% of all cancer-associated deaths. Yet, even with aggressive interventions for advanced lung cancer, the five-year survival rate remains low, at around 15%. The hedgehog signaling pathway is highly conserved during embryonic development and is involved in tissue homeostasis as well as organ development. However, studies have documented an increasing prevalence of aberrant activation of HH signaling in lung cancer patients, promoting malignant lung cancer progression with poor prognostic outcomes. Inhibitors targeting the HH pathway have been widely used in tumor therapy, however, they still cannot avoid the occurrence of drug resistance. Interestingly, natural products, either alone or in combination with chemotherapy, have greatly improved overall survival outcomes for lung cancer patients by acting on the HH signaling pathway because of its unique and excellent pharmacological properties. In this review, we elucidate on the underlying molecular mechanisms through which the HH pathway promotes malignant biological behaviors in lung cancer, as well as the potential of inhibitors or natural compounds in targeting HH signaling for clinical applications in lung cancer therapy.

Triptonide effectively inhibits triple-negative breast cancer metastasis through concurrent degradation of Twist1 and Notch1 oncoproteins

Background

Triple-negative breast cancer (TNBC) is highly metastatic and lethal. Due to a lack of druggable targets for this disease, there are no effective therapies in the clinic.

Methods

We used TNBC cells and xenografted mice as models to explore triptonide-mediated inhibition of TNBC metastasis and tumor growth. Colony formation assay was used to quantify the tumorigenesis of TNBC cells. Wound-healing and cell trans-well assays were utilized to measure cell migration and invasion. Tube formation assay was applied to access tumor cell-mediated vasculogenic mimicry. Western blot, quantitative-PCR, immunofluorescence imaging, and immunohistochemical staining were used to measure the expression levels of various tumorigenic genes in TNBC cells.

Results

Here, we showed that triptonide, a small molecule from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, potently inhibited TNBC cell migration, invasion, and vasculogenic mimicry, and effectively suppressed TNBC tumor growth and lung metastasis in xenografted mice with no observable toxicity. Molecular mechanistic studies revealed that triptonide strongly triggered the degradation of master epithelial-mesenchymal transition (EMT)-inducing protein Twist1 through the lysosomal system and reduced Notch1 expression and NF-κB phosphorylation, which consequently diminished the expression of pro-metastatic and angiogenic genes N-cadherin, VE-cadherin, and vascular endothelial cell growth factor receptor 2 (VEGFR2).

Conclusions

Triptonide effectively suppressed TNBC cell tumorigenesis, vasculogenic mimicry, and strongly inhibited the metastasis of TNBC via degradation of Twist1 and Notch1 oncoproteins, downregulation of metastatic and angiogenic gene expression, and reduction of NF-κB signaling pathway. Our findings provide a new strategy for treating highly lethal TNBC and offer a potential new drug candidate for combatting this aggressive disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01488-7.

Targeting cancer stem cells by nutraceuticals for cancer therapy

Accumulating evidence has demonstrated that cancer stem cells (CSCs) play an essential role in tumor progression and reoccurrence and drug resistance. Multiple signaling pathways have been revealed to be critically participated in CSC development and maintenance. Emerging evidence indicates that numerous chemopreventive compounds, also known as nutraceuticals, could eliminate CSCs in part via regulating several signaling pathways. Therefore, in this review, we will describe the some natural chemopreventive agents that target CSCs in a variety of human malignancies, including soy isoflavone, curcumin, resveratrol, tea polyphenols, sulforaphane, quercetin, indole-3-carbinol, 3,3'-diindolylmethane, withaferin A, apigenin, etc. Moreover, we discuss that eliminating CSCs by nutraceuticals might be a promising strategy for treating human cancer via overcoming drug resistance and reducing tumor reoccurrence.

The vital role of Gli1+ mesenchymal stem cells in tissue development and homeostasis

The hedgehog (Hh) signaling pathway plays an essential role in both tissue development and homeostasis. Glioma-associated oncogene homolog 1 (Gli1) is one of the vital transcriptional factors as well as the direct target gene in the Hh signaling pathway. The cells expressing the Gli1 gene (Gli1⁺ cells) have been identified as mesenchymal stem cells (MSCs) that are responsible for various tissue developments, homeostasis, and injury repair. This review outlines some recent discoveries on the crucial roles of Gli1⁺ MSCs in the development and homeostasis of varieties of hard and soft tissues.

Identification of triptonide as a therapeutic agent for triple negative breast cancer treatment

Triple-negative breast cancer (TNBC) is associated with a high rate of early recurrence and distant metastasis, frequent development of therapeutic resistance, and a poor prognosis. There is a lack of targeted therapies for this aggressive subtype of breast cancer. Identifying novel effective treatment modalities for TNBC remains an urgent and unmet clinical need. In this study, we investigated the anti-cancer effect of triptonide, a natural compound derived from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, in TNBC. We found that triptonide inhibits human TNBC cell growth in vitro and growth of TNBC xenograft mammary tumors. It induces apoptosis and suppresses stem-like properties as indicated by reduced mammosphere formation and aldehyde dehydrogenase activity in TNBC cells. We show that triptonide downregulates multiple cancer stem cell-associated genes but upregulates SNAI1 gene expression. In support of SNAI1 induction as a negative feedback response to triptonide treatment, in vitro-derived triptonide-resistant HCC1806 cells display a markedly higher expression of SNAI1 compared with parental cells. Mechanistically, the increase of SNAI1 expression is mediated by the activation of JNK signaling, but not by ERK and AKT, two well-established SNAI1 regulators. Furthermore, knockdown of SNAI1 in the triptonide-resistant HCC1806 cells increases sensitivity to triptonide and reduces mammosphere formation. These results indicate that triptonide holds promise as a novel anti-tumor agent for TNBC treatment. Our study also reveals a SNAI1-associated feedback mechanism which may lead to acquired resistance to triptonide.

Activation of the tumor suppressive Hippo pathway by triptonide as a new strategy to potently inhibit aggressive melanoma cell metastasis

Metastatic melanoma has a very high mortality rate despite the availability of chemotherapy, radiotherapy, and immunotherapy; therefore, more effective therapeutics are needed. The Hippo pathway plays an inhibitory role in melanoma progression, but the tumor suppressors Salvador homolog-1 (SAV1) and large tumor suppressor 1 (LATS1) in this pathway are down-regulated in melanoma. As a result, the downstream oncogenic Yes-associated protein (YAP) is active, resulting in uncontrolled melanoma growth and metastasis. Therapeutics for remedying SAV1 and LATS1 deficiency in melanoma have not yet been reported in the literature. Here, we show that the small molecule triptonide (MW 358 Da) robustly suppressed melanoma cell tumorigenicity, migration, and invasion. Furthermore, triptonide markedly reduced tumor growth and melanoma lung metastasis in tumor-bearing mice with low toxicity. Molecular mechanistic studies revealed that triptonide promoted SAV1 and LATS1 expression, strongly activated the tumor-suppressive Hippo pathway, degraded oncogenic YAP via the lysosomal pathway, and reduced levels of tumorigenic microphthalmia-associated transcription factor (MITF) in melanoma cells. Triptonide also strongly inhibited activation of AKT, a SAV1-binding signaling protein. Collectively, our results conceptually demonstrate that induction of SAV1 and LATS1 expression and activation of the tumor-suppressive Hippo pathway by triptonide potently inhibits aggressive melanoma cell growth and metastasis. These findings suggest a new strategy for developing therapeutics to treat metastatic melanoma and highlight a novel drug candidate against aggressive melanoma.

Natural small molecule triptonide inhibits lethal acute myeloid leukemia with FLT3-ITD mutation by targeting Hedgehog/FLT3 signaling

Acute myeloid leukemia harboring internal tandem duplication of FMS-like tyrosine kinase 3 (FLT3-ITD AML) is a subset of highly aggressive malignancies with poor clinical outcome. Despite some advances in the development of FLT3 tyrosine kinase inhibitors (FLT3 inhibitors), most of FLT3-ITD AML patients suffer from lethal disease relapse, suggesting the requirement of novel targets and agents. Here we describe a natural small molecule, triptonide that can efficiently inhibit FLT3-ITD-driven AML in vitro and in vivo. Mechanistically, triptonide targeted Hedgehog/FLT3 signaling by inhibiting its critical effectors, which are GLI2, c-Myc and FLT3 and induced apoptosis of FLT3-ITD-driven leukemia cells. In addition, we also observed that triptonide activated tumor suppressor p53. In vivo, triptonide treatment markedly suppressed lethal FLT3-ITD-driven AML with good tolerance and prolonged survival time in orthotopic mouse model. Our studies identify Hedgehog/FLT3 axis as a novel target for treating FLT3-ITD-driven leukemia and demonstrate that triptonide is an active lead compound that can kill FLT3-ITD-driven leukemia cells.

Intravenous Administration of Triptonide Attenuates CFA-Induced Pain Hypersensitivity by Inhibiting DRG AKT Signaling Pathway in Mice

Background

Currently, medical treatment of inflammatory pain is limited by a lack of safe and effective therapies. Triptonide (TPN), a major component of Tripterygium wilfordii Hook.f. with low toxicity, has been shown to have good anti-inflammatory and neuroprotective effects. The present study aims to investigate the effects of TPN on chronic inflammatory pain.

Materials and Methods

Inflammatory pain was induced by intraplantar injection of complete Freund’s adjuvant (CFA). TPN’s three different doses were intravenously administered to compare the analgesic efficacy: 0.1 mg/kg, 0.5 mg/kg, and 2.0 mg/kg. The foot swelling was quantitated by measuring paw volume. Mechanical allodynia and thermal hyperalgesia were assessed with von Frey filament testing and Hargreaves’ test, respectively. Western blots, qRT–PCR and immunofluorescence tests were used to analyze the expression of pAKT, tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). Two AKT inhibitors, AKT inhibitor Ⅳ and MK-2206, were used to examine AKT’s effects on pain behavior and cytokines expression.

Results

Intravenous treatment with TPN attenuated CFA-induced paw edema, mechanical allodynia, and thermal hyperalgesia. Western blotting and immunofluorescence results showed that CFA induced AKT activation in the dorsal root ganglion (DRG) neurons. However, these effects were suppressed by treatment with TPN. Furthermore, TPN treatment inhibited CFA-induced increase of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. Consistent with the in vivo data, TPN inhibited LPS-induced Akt phosphorylation and inflammatory mediator production in ND7/23 cells. Finally, intrathecal treatment with AKT inhibitor Ⅳ or MK-2206, attenuated CFA-induced mechanical allodynia and thermal hyperalgesia, and simultaneously decreased the mRNA expression of TNF-α, IL-1β, and IL-6 in DRG.

Conclusion

These data indicate that TPN attenuates CFA-induced pain potentially via inhibiting AKT-mediated pro-inflammatory cytokines production in DRG. TPN may be used for the treatment of chronic inflammatory pain.

Downregulation of miR-506-3p Facilitates EGFR-TKI Resistance through Induction of Sonic Hedgehog Signaling in Non-Small-Cell Lung Cancer Cell Lines

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation eventually develop resistance to EGFR-targeted tyrosine kinase inhibitors (TKIs). Treatment resistance remains the primary obstacle to the successful treatment of NSCLC. Although drug resistance mechanisms have been studied extensively in NSCLC, the regulation of these mechanisms has not been completely understood. Recently, increasing numbers of microRNAs (miRNAs) are implicated in EGFR-TKI resistance, indicating that miRNAs may serve as novel targets and may hold promise as predictive biomarkers for anti-EGFR therapy. MicroRNA-506 (miR-506) has been identified as a tumor suppressor in many cancers, including lung cancer; however, the role of miR-506 in lung cancer chemoresistance has not yet been addressed. Here we report that miR-506-3p expression was markedly reduced in erlotinib-resistant (ER) cells. We identified Sonic Hedgehog (SHH) as a novel target of miR-506-3p, aberrantly activated in ER cells. The ectopic overexpression of miR-506-3p in ER cells downregulates SHH signaling, increases E-cadherin expression, and inhibits the expression of vimentin, thus counteracting the epithelial-mesenchymal transition (EMT)-mediated chemoresistance. Our results advanced our understanding of the molecular mechanisms underlying EGFR-TKI resistance and indicated that the miR-506/SHH axis might represent a novel therapeutic target for future EGFR mutated lung cancer treatment.

lncRNA involved in triptonide-induced cytotoxicity in mouse germ cells

Triptonide reportedly has strong antitumor and anti-inflammatory activities. However, its severe toxicity, including to the reproductive system, has greatly restricted its use in patients who wish to preserve fertility. lncRNAs play crucial roles in male fertility and reportedly regulate triptonide's antitumor activity. However, whether lncRNAs are involved in triptonide-induced reproductive toxicity is unknown. Here, we showed that triptonide induced significant cytotoxicity, as demonstrated by reduced cell viability and induction of apoptosis and autophagy in mouse germ cells (a spermatocyte cell line, GC2). The expression levels of numerous lncRNAs and mRNAs in GC2 cells were altered at the transcriptome level after treatment with triptonide for 24 h, as determined by RNA sequencing. Gene ontology and pathway analyses showed that the functions of the differentially expressed lncRNAs and mRNAs were closely linked with many processes, including gene expression regulation, cell death, cell cycle regulation, cell proliferation and development and others. After validating our RNA-seq data, we selected one lncRNA, Obox4-ps35, dramatically induced by triptonide for further investigation. Obox4-ps35 knock-out aggravated triptonide-induced cytotoxicity by decreasing cell survival and increasing apoptosis and autophagy rates. These data suggest that germ cells exposed to triptonide overexpress Obox4-ps35 to protect against triptonide-induced cytotoxicity. This study provides preliminary evidence and novel directions for exploring roles of lncRNAs in triptonide-induced cytotoxicity, especially in reproductive toxicity.

Glochidiol, a natural triterpenoid, exerts its anti-cancer effects by targeting the colchicine binding site of tubulin

Glochidiol has been shown to have potentially antiproliferative activity in vitro, however its anticancer mechanisms specifically against lung cancer remain unknown. This study aimed to investigate the anti-lung cancer effects of glochidiol in HCC-44 cells in vitro and in vivo. In the present study, glochidiol was found to have potent antiproliferative activity against lung cancer cell lines NCI-H2087, HOP-62, NCI-H520, HCC-44, HARA, EPLC-272H, NCI-H3122, COR-L105 and Calu-6 with IC₅₀ values of 4.12 µM, 2.01 µM, 7.53 µM, 1.62 µM, 4.79 µM, 7.69 µM, 2.36 µM, 6.07 µM and 2.10 µM, respectively. In vivo, glochidiol was found to effectively inhibit lung cancer HCC-44 xenograft tumor growth in nude mice. Docking analysis found that glochidiol forms hydrogen bonds with residues of tubulin. Glochidiol was also found to inhibit tubulin polymerization in vitro with an IC₅₀ value of 2.76 µM. Immunofluorescence staining and EBI competition assay suggest that glochidiol may interact with tubulin by targeting the colchicine binding site. Thus, glochidiol might be a novel colchicine binding site inhibitor with the potential to treat lung cancer.

Cancer Stem Cells Equipped with Powerful Hedgehog Signaling and Better Epigenetic Memory: Avenues to Look for Cancer Therapeutics

Complex nature of the tumor is depicted at the cellular landscape by showing heterogeneity in the presence of cancer cells, cancer-associated stromal cells, mesenchymal stem cells and cancer stem cells (CSCs). One of the plausible views in cancer formation is suggested as the theory of cancer CSCs that is known as a source of initiation of tumorigenesis. In essence, these powerful CSCs are equipped with high Sonic Hedgehog (SHH) signaling and epigenetic memory power that support various tumor hallmarks. Truly, nature justifies its intent by limiting these stem cells with a potential to turn into CSCs and in turn suppressing the high risk of humans and other organisms. In short, this mini-review addresses the contribution of SHH signaling to allow reprogramming of epigenetic memory within CSCs that support tumor hallmarks. Besides, this paper explores therapeutic approaches to mitigate SHH signaling that may lead to a blockade of the pro-tumor potential of CSCs.

Triptonide Modulates MAPK Signaling Pathways and Exerts Anticancer Effects via ER Stress-Mediated Apoptosis Induction in Human Osteosarcoma Cells

Background

Osteosarcoma (OS) is the most common primary malignancy arise from bone and is one of the causes of cancer-related deaths. Triptonide (TN), a diterpenoid epoxide presented in Tripterygium wilfordii, is shown to possess a broad spectrum of biological properties.

Methods

In this study, we investigate the growth inhibitory effect of TN against human OS cells and its underlying molecular mechanism of action.

Results

Findings of our in vitro study revealed that TN exhibited a dose-dependent cytotoxic effect in MG63 and U-2OS cells. ROS-mediated cytotoxic effect was achieved in OS cells treated with TN which was reversed upon NAC treatment. Significantly, increased expression of PERK, p-EIF2, GRP78, ATF4 and CHOP in TN-treated OS cells unfolds the molecular mechanism of TN targets ER stress-mediated apoptosis. Modulation of ERK MAPK pathway was also observed as evidenced by the increased phosphorylation of ERK (p-ERK) and p-p38 in TN-treated OS cells.

Conclusion

Altogether, the outcome of the study for the first time revealed that TN exhibited its potential chemotherapeutic effects through ROS-mediated ER stress-induced apoptosis via p38 and ERK MAPK signaling pathways.

Triptonide inhibits metastasis potential of thyroid cancer cells via astrocyte elevated gene-1

Background

Triptonide (TN) was recently proved to have anti-tumor effects. The current study explored whether TN inhibited thyroid cancer and the possible underlying mechanism.

Methods

MDA-T68 and BCPAP cells were treated by TN. Cell viability, migration and invasion rate were detected by MTT and Transwell. Protein expressions were determined by Western blot and mRNA expressions were detected by Real-time Quantitative PCR (qPCR).

Results

TN at the concentration higher than 50 nmol/L inhibited cell viability, migration and invasion of MDA-T68 and BCPAP cells, and astrocyte elevated gene (AEG-1) expression, was decreased by TN at the concentration higher than 50 nmol/L. Furthermore, AEG-1 overexpression inhibited cell viability, migration and invasion capacity of MDA-T68 and BCPAP cells, while TN reduced AEG-1 expression, and weaken the effect of AEG-1 overexpression on cell viability, migration and invasion capacities. Moreover, TN depressed the increase of matrix metalloproteinase (MMP) 2, MMP9 and N-cadherin expressions caused by AEG-1 overexpression. Meanwhile, E-cadherin expression reduced by AEG-1 overexpression was increased by TN.

Conclusions

TN could inhibit the metastasis potential of thyroid cancer cells through inhibiting the expression of AEG-1. Our findings reveal the mechanism of TN in the treatment of thyroid cancer, which should be further explored in the study of thyroid cancer.

Keywords

Triptonide; metastasis; thyroid cancer; regulation; drug monomer

Triptonide effectively suppresses gastric tumor growth and metastasis through inhibition of the oncogenic Notch1 and NF-κB signaling pathways

Gastric cancer ranks as the third leading cause of cancer-related death worldwide. The uncontrolled tumor growth and robust metastasis are key factors to cause the cancer patient death. Mechanistically, aberrant activation of Notch and NF-κB signaling pathways plays pivotal roles in the initiation and metastasis of gastric cancer. Despite great efforts have been made in recent decades, the effective drug against the advanced and metastatic gastric cancer is still lacking in the clinical setting. In this study, we found that triptonide, a small molecule (MW358) purified from the traditional Chinese medicinal herb Tripterygium wilfordii Hook F, effectively suppressed tumor growth and metastasis in xenograft mice without obvious toxicity at the doses we tested, resulting in potent anti-gastric cancer effect with low toxicity. Triptonide markedly inhibited human metastatic gastric cancer cell migration, invasion, proliferation, and tumorigenicity. Molecular mechanistic studies revealed that triptonide significantly reduced Notch1 protein levels in metastatic gastric cancer cells through degrading the oncogenic protein Notch1 via the ubiquitin-proteasome pathway. Consequently, the levels of Notch1 downstream proteins RBPJ, IKKα, IKKβ were significantly diminished, and nuclear factor-kappa B (NF-κB) phosphorylation was significantly reduced. Together, triptonide effectively suppresses gastric cancer growth and metastasis via inhibition of the oncogenic Notch1 and NF-κB signaling pathways. Our findings provide a new strategy and drug candidate for treatment of the advanced and metastatic gastric cancer.

Cancer stem cells in esophageal squamous cell cancer

Cancer stem cells (CSCs) are hypothesized to govern the origin, progression, drug resistance, recurrence and metastasis of human cancer. CSCs have been identified in nearly all types of human cancer, including esophageal squamous cell cancer (ESCC). Four major methods are typically used to isolate or enrich CSCs, including: i) fluorescence-activated cell sorting or magnetic-activated cell sorting using cell-specific surface markers; ii) stem cell markers, including aldehyde dehydrogenase 1 family member A1; iii) side population cell phenotype markers; and iv) microsphere culture methods. ESCC stem cells have been identified using a number of these methods. An increasing number of stem cell signatures and pathways have been identified, which have assisted in the clarification of molecular mechanisms that regulate the stemness of ESCC stem cells. Certain viruses, such as human papillomavirus and hepatitis B virus, are also considered to be important in the formation of CSCs, and there is a crosstalk between stemness and viruses-associated genes/pathways, which may suggest a potential therapeutic strategy for the eradication of CSCs. In the present review, findings are summarized along these lines of inquiry.

Triptonide acts as a novel antiprostate cancer agent mainly through inhibition of mTOR signaling pathway

BACKGROUND

The increasing incidence of prostate cancer (PCa) indicates an urgent need for the development of new effective drugs in PCa therapy. Triptonide has been reported to have a strong inhibition activity in cancers through screening of Chinese herbal medicine. This study aims to investigate the effects of triptonide on anti-PCa activity and its mechanisms.

METHODS

Three human advanced PCa cell lines PC3, DU145, and LNCap, and a human normal prostate epithelial cell line RWPE were treated with a range (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, and 320 nM) of triptonide concentrations for 72 hours respectively. Then, cell viability was assessed by cell counting kit-8. PCa cells were treated with different doses (0-20 nM) of triptonide for 72 hours. Cell cycle and apoptosis were assessed by flow cytometry assays. Nude mice bearing human PCa xenografts were intraperitoneally injected daily with either triptonide (10 mg/kg/d) or phosphate-buffered saline as a control for 35 days. RNA-sequencing (RNA-seq) was performed by an Illumina Hiseq Sequencing platform and confirmed by a real-time polymerase chain reaction. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and ingenuity pathway analysis were used to analyze RNA-seq results.

RESULTS

Triptonide effectively inhibits the proliferation of human PCa cells PC3, DU145, and LNCap in vitro with their IC₅₀ values as 11.961, 10.259, and 12.012 nM, respectively. Triptonide (10 mg/kg) potently inhibits the growth of PCa cell xenografts in vivo at an inhibition rate of over 97.95%. Treatment with triptonide (5 nM) significantly promotes cell apoptosis and retaining cell-cycle arrest in the G2/M phase. RNA-seq data revealed that total of 936 genes were upregulated or downregulated in triptonide treated. Moreover, the phosphorylation of mechanistic target of rapamycin (mTOR) and the downstream protein p70S6K were both inhibited, most obviously in PCa cells.

CONCLUSIONS

Our findings suggest that triptonide can efficaciously suppress PCa growth in vitro and in vivo via inhibiting the phosphorylation of mTOR and the activities of related downstream signaling pathways.

Selective activation of tumor-suppressive MAPKP signaling pathway by triptonide effectively inhibits pancreatic cancer cell tumorigenicity and tumor growth

The mitogen-activated protein kinase (MAPK, 1K) family members ERK, JNK, and p38 play a divergent role in either promoting tumorigenesis or tumor-suppression. Activation of ERK and JNK promotes tumorigenesis; whereas, escalation of p38 inhibits carcinogenesis. As these three MAPK members are controlled by the common up-stream MAPK signaling proteins which consist of MAPK kinases (2K) and MAPK kinase kinases (3K), how to selectively actuate tumor-suppressive p38, not concurrently stimulate tumorigenic ERK and JNK, in cancer cells is a challenge for cancer researchers, and a new opportunity for novel anti-cancer drug discovery. Using human pancreatic cancer cells and xenograft mice as models, we found that a small molecule triptonide first discerningly activated the up-stream MAPK kinase kinase MEKK4, not the other two 3K members ASK1 and GADD45; and then selectively actuated the middle stream MAPK kinase MKK4, not the other two 2K members MKK3 and MKK6; and followed by activation of the MAPK member p38, not the other two members ERK and JNK. These data suggest that triptonide is a selective MEKK4-MKK4-p38 axis agonist. Consequently, selective activation of the MEKK4-MKK4-p38 signaling axis by triptonide activated tumor suppressor p21 and inhibited CDK3 expression, resulting in cancer cell cycle arrest at G2/M phase and marked inhibition of pancreatic cancer cell tumorigenic capability in vitro and tumor growth in xenograft mice. Our findings support the notion that selective activation of tumor-suppressive MEKK4-MKK4-p38-p21signaling pathway by triptonide is a new approach for pancreatic cancer therapy, providing a new drug candidate for development of novel anti-cancer therapeutics.