Plumbagin induces growth inhibition of human glioma cells by downregulating the expression and activity of FOXM1

Forkhead box transcription factors (FOXOs and FOXM1) in glioma: from molecular mechanisms to therapeutics

Glioma is the most aggressive and malignant type of primary brain tumor, comprises the majority of central nervous system deaths, and is categorized into different subgroups according to its histological characteristics, including astrocytomas, oligodendrogliomas, glioblastoma multiforme (GBM), and mixed tumors. The forkhead box (FOX) transcription factors comprise a collection of proteins that play various roles in numerous complex molecular cascades and have been discovered to be differentially expressed in distinct glioma subtypes. FOXM1 and FOXOs have been recognized as crucial transcription factors in tumor cells, including glioma cells. Accumulating data indicates that FOXM1 acts as an oncogene in various types of cancers, and a significant part of studies has investigated its function in glioma. Although recent studies considered FOXO subgroups as tumor suppressors, there are pieces of evidence that they may have an oncogenic role. This review will discuss the subtle functions of FOXOs and FOXM1 in gliomas, dissecting their regulatory network with other proteins, microRNAs and their role in glioma progression, including stem cell differentiation and therapy resistance/sensitivity, alongside highlighting recent pharmacological progress for modulating their expression.

SOCS7/HuR/FOXM1 signaling axis inhibited high-grade serous ovarian carcinoma progression

Background

High-grade serous ovarian carcinoma (HGSOC) is clinically dominant and accounts for ~ 80% deaths in all types of ovarian cancer. The delayed diagnosis, rapid development, and wide dissemination of HGSOC collectively contribute to its high mortality rate and poor prognosis in the patients. Suppressors of cytokine signaling 7 (SOCS7) can regulate cytokine signaling and participate in cell cycle arrest and regulation of cell proliferation, which might also be involved in carcinogenesis. Here, we designated to investigate the functions and mechanisms of SOCS7 in HGSOC.

Methods

The clinical correlation between SOCS7 and HGSOC was examined by both bioinformatics and analysis of tissue samples in patients. Gain/Loss-of-function examinations were carried out to assess the effectiveness of SOCS7 in cell viability, cell cycle, and tumor growth of HGSOC. Furthermore, the underlying mechanisms were explored by identifying the downstream proteins and their interactions via proteomics analysis and immunoprecipitation.

Results

The expression of SOCS7, which was decreased in HGSOC tissues, was correlated with the clinical pathologic characteristics and overall survival of HGSOC patients. SOCS7 acted as a HGSOC suppressor by inhibiting cancer cell viability and tumor growth in vivo. The anti-HGSOC mechanism involves SOCS7’s regulatory effect on HuR by mediating its ubiquitination, the regulation of FOXM1 mRNA by HuR, as well as the interplays among these three clinically relevant factors.

Conclusions

The SOCS7 correlates with HGSOC and suppresses its tumorigenesis through regulating HuR and FOXM1, which also suggests that SOCS7 is a prospective biomarker for the clinical management of ovarian cancer, especially HGSOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02395-1.

Antioxidants in brain tumors: current therapeutic significance and future prospects

Brain cancer is regarded among the deadliest forms of cancer worldwide. The distinct tumor microenvironment and inherent characteristics of brain tumor cells virtually render them resistant to the majority of conventional and advanced therapies. Oxidative stress (OS) is a key disruptor of normal brain homeostasis and is involved in carcinogenesis of different forms of brain cancers. Thus, antioxidants may inhibit tumorigenesis by preventing OS induced by various oncogenic factors. Antioxidants are hypothesized to inhibit cancer initiation by endorsing DNA repair and suppressing cancer progression by creating an energy crisis for preneoplastic cells, resulting in antiproliferative effects. These effects are referred to as chemopreventive effects mediated by an antioxidant mechanism. In addition, antioxidants minimize chemotherapy-induced nonspecific organ toxicity and prolong survival. Antioxidants also support the prooxidant chemistry that demonstrate chemotherapeutic potential, particularly at high or pharmacological doses and trigger OS by promoting free radical production, which is essential for activating cell death pathways. A growing body of evidence also revealed the roles of exogenous antioxidants as adjuvants and their ability to reverse chemoresistance. In this review, we explain the influences of different exogenous and endogenous antioxidants on brain cancers with reference to their chemopreventive and chemotherapeutic roles. The role of antioxidants on metabolic reprogramming and their influence on downstream signaling events induced by tumor suppressor gene mutations are critically discussed. Finally, the review hypothesized that both pro- and antioxidant roles are involved in the anticancer mechanisms of the antioxidant molecules by killing neoplastic cells and inhibiting tumor recurrence followed by conventional cancer treatments. The requirements of pro- and antioxidant effects of exogenous antioxidants in brain tumor treatment under different conditions are critically discussed along with the reasons behind the conflicting outcomes in different reports. Finally, we also mention the influencing factors that regulate the pharmacology of the exogenous antioxidants in brain cancer treatment. In conclusion, to achieve consistent clinical outcomes with antioxidant treatments in brain cancers, rigorous mechanistic studies are required with respect to the types, forms, and stages of brain tumors. The concomitant treatment regimens also need adequate consideration.

Natural bioactive molecules: An alternative approach to the treatment and control of glioblastoma multiforme

Glioblastoma multiforme is one of the most deadly malignant tumors, with more than 10,000 cases recorded annually in the United States. Various clinical analyses and studies show that certain chronic diseases, including cancer, interact between cell-reactive radicals rise and pathogenesis. Reactive oxygen and nitrogenous sources include endogenous (physiological processes), and exogenous sources contain reactive oxygen and nitrogen (xenobiotic interaction). The cellular oxidation/reduction shifts to oxidative stress when the regulation mechanisms of antioxidants are surpassed, and this raises the ability to damage cellular lipids, proteins, and nucleic acids. OBJECTIVE: This review is focused on how phytochemicals play crucial role against glioblastoma multiforme and to combat these, bioactive molecules and their derivatives are either used alone, in combination with anticancer drugs or as nanomedicine formulations for better cancer theranostics over the conventional approach. CONCLUSION: Bioactive molecules found in seeds, vegetables, and fruits have antioxidant, anti-inflammatory, and anticancer properties that may help cancer survivors feel better throughout chemotherapy or treatment. However, incorporating them into the nanocarrier-based drug delivery for the treatment of GBMs, which could be a promising therapeutic strategy for this tumor entity, increasing targeting effectiveness, increasing bioavailability, and reducing side effects with this target-specificity, drug internalization into cells is significantly improved, and off-target organ aggregation is reduced.

Anticancer Effects and Mechanisms of Action of Plumbagin: Review of Research Advances

Plumbagin (PLB), a natural naphthoquinone constituent isolated from the roots of the medicinal plant Plumbago zeylanica L., exhibited anticancer activity against a variety of cancer cell lines including breast cancer, hepatoma, leukemia, melanoma, prostate cancer, brain tumor, tongue squamous cell carcinoma, esophageal cancer, oral squamous cell carcinoma, lung cancer, kidney adenocarcinoma, cholangiocarcinoma, gastric cancer, lymphocyte carcinoma, osteosarcoma, and canine cancer. PLB played anticancer activity via many molecular mechanisms, such as targeting apoptosis, autophagy pathway, cell cycle arrest, antiangiogenesis pathway, anti-invasion, and antimetastasis pathway. Among these signaling pathways, the key regulatory genes regulated by PLB were NF-kβ, STAT3, and AKT. PLB also acted as a potent inducer of reactive oxygen species (ROS), suppressor of cellular glutathione, and novel proteasome inhibitor, causing DNA double-strand break by oxidative DNA base damage. This review comprehensively summarizes the anticancer activity and mechanism of PLB.

DKC1 enhances angiogenesis by promoting HIF-1α transcription and facilitates metastasis in colorectal cancer

BACKGROUND

Dyskeratosis congenita 1 (DKC1) is dysregulated in several cancers. However, the expression and function of DKC1 in colorectal cancer (CRC) is rarely reported.

METHODS

Tissue microarrays (TAMs) including 411 cases of CRC tissues and corresponding paracancerous tissues were used to examine the DKC1 expression. The correlations between the DKC1 expression and clinicopathological or survival characters were further analysed. The functions and molecular mechanism of DKC1 in CRC were investigated through a series of in vitro and in vivo experiments.

RESULTS

The result showed that DKC1 expression was increased in CRC tissues. Increased DKC1 expression was associated with high grade of TNM stage, additional lymph node metastasis, and poor prognosis of patients with CRC. Multivariate COX analysis indicated that DKC1 can act as an independent prognostic factor for patients with CRC. DKC1 also facilitated the CRC angiogenesis and metastasis by increasing HIF-1α and VEGF expression levels. Chromatin immunoprecipitation assay demonstrated that DKC1 facilitated HIF-1α expression by regulating HIF-1α promoter activity.

CONCLUSION

DKC1 appears to regulate CRC angiogenesis and metastasis through directly activating HIF-1α transcription. DKC1 can serve as an accurate indicator in predicting the prognosis of patients with CRC and act as a potential therapeutic target for CRC.

Protein Phosphatases-A Touchy Enemy in the Battle Against Glioblastomas: A Review

Glioblastoma (GBM) is the most common malignant tumor arising from brain parenchyma. Although many efforts have been made to develop therapies for GBM, the prognosis still remains poor, mainly because of the difficulty in total resection of the tumor mass from brain tissue and the resistance of the residual tumor against standard chemoradiotherapy. Therefore, novel adjuvant therapies are urgently needed. Recent genome-wide analyses of GBM cases have clarified molecular signaling mechanisms underlying GBM biology. However, results of clinical trials targeting phosphorylation-mediated signaling have been unsatisfactory to date. Protein phosphatases are enzymes that antagonize phosphorylation signaling by dephosphorylating phosphorylated signaling molecules. Recently, the critical roles of phosphatases in the regulation of oncogenic signaling in malignant tumor cells have been reported, and tumorigenic roles of deregulated phosphatases have been demonstrated in GBM. However, a detailed mechanism underlying phosphatase-mediated signaling transduction in the regulation of GBM has not been elucidated, and such information is necessary to apply phosphatases as a therapeutic target for GBM. This review highlights and summarizes the phosphatases that have crucial roles in the regulation of oncogenic signaling in GBM cells.

FoxM1 drives ADAM17/EGFR activation loop to promote mesenchymal transition in glioblastoma

Mesenchymal transition (MES transition) is a hallmark of glioblastoma multiforme (GBM), however, the mechanism regulating the process remains to be elucidated. Here we report that FoxM1 drives ADAM17/EGFR activation loop to promote MES transition in GBM. Firstly, FoxM1 expression was positively associated with ADAM17 expression, and their expression was correlated with the mesenchymal features and overall patient survival of GBM. Overexpressing FoxM1 or ADAM17 increased the mesenchymal phenotype of glioma cells, which could be reversed by silencing FoxM1 or ADAM17. Importantly, FoxM1 bound to the ADAM17 promoter to transcriptionally upregulate its expression. Using gain- and loss-of-function studies, we showed that FoxM1/ADAM17 axis promoted the MES transition in glioma cells. Moreover, tissue microarray analysis and orthotopic xenograft model further confirmed that FoxM1/ADAM17 axis played key roles in malignancy of GBM. Mechanistically, FoxM1/ADAM17 axis activated the EGFR/AKT/GSK3β signaling pathway and ADAM17/EGFR/GSK3β axis could maintain FoxM1 stability in glioma cells. Taken together, our study demonstrated that FoxM1/ADAM17 feedback loop controlled the MES transition and regulated the progression of GBM, raising the possibility that deregulation of this loop might improve the durability of therapies in GBM.

Oxidative stress via inhibition of the mitochondrial electron transport and Nrf-2-mediated anti-oxidative response regulate the cytotoxic activity of plumbagin

Plumbagin, an anti-cancer agent, is toxic to cells of multiple species. We investigated if plumbagin targets conserved biochemical processes. Plumbagin induced DNA damage and apoptosis in cells of diverse mutational background with comparable potency. A 3-5 fold increase in intracellular oxygen radicals occurred in response to plumbagin. Neutralization of the reactive oxygen species by N-acetylcysteine blocked apoptosis, indicating a central role for oxidative stress in plumbagin-mediated cell death. Plumbagin docks in the ubiquinone binding sites (Q0 and Qi) of mitochondrial complexes I-III, the major sites for oxygen radicals. Plumbagin decreased oxygen consumption rate, ATP production and optical redox ratio (NAD(P)H/FAD) indicating interference with electron transport downstream of mitochondrial Complex II. Oxidative stress induced by plumbagin triggered an anti-oxidative response via activation of Nrf2. Plumbagin and the Nrf2 inhibitor, brusatol, synergized to inhibit cell proliferation. These data indicate that while inhibition of electron transport is the conserved mechanism responsible for plumbagin's chemotoxicity, activation of Nrf2 is the resulting anti-oxidative response that allows plumbagin to serve as a chemopreventive agent. This study provides the basis for designing potent and selective plumbagin analogs that can be coupled with suitable Nrf2 inhibitors for chemotherapy or administered as single agents to induce Nrf2-mediated chemoprevention.

Kukoamine A inhibits human glioblastoma cell growth and migration through apoptosis induction and epithelial-mesenchymal transition attenuation

Cortex lycii radicis is the dried root bark of Lycium chinense, a traditional Chinese herb used in multiple ailments. The crude extract of Cortex lycii radicis has growth inhibition effect on GBM cells. Kukoamine A (KuA) is a spermine alkaloid derived from it. KuA possesses antioxidant, anti-inflammatory activities, but its anticancer activity is unknown. In this study, the growth and migration inhibition effect of KuA on human GBM cells and the possible mechanism of its activity were investigated. After KuA treatment, proliferation and colony formation of GBM cells were decreased significantly; apoptotic cells were increased; the cell cycle was arrested G0/G₁ phase; the migration and invasion were decreased, the growth of tumors initiated from GBM cells was inhibited significantly; the expressions of 5-Lipoxygenase (5-LOX) were decreased, apoptotic proteins, Bax and caspase-3 were increased, and antiapoptotic protein Bcl-2 was decreased significantly; The expressions of CCAAT/enhancer binding protein β (C/EBPβ), N-cadherin, vimentin, twist and snail+slug were decreased significantly, while the expression of E-cadherin was increased significantly in KuA treated GBM cells and tumor tissues. KuA inhibited human glioblastoma cell growth and migration in vitro and in vivo through apoptosis induction and epithelial-mesenchymal transition attenuation by downregulating expressions of 5-LOX and C/EBPβ.

Plumbagin Suppresses the Invasion of HER2-Overexpressing Breast Cancer Cells through Inhibition of IKKα-Mediated NF-κB Activation

HER2-overexpressing breast cancers account for about 30% of breast cancer occurrences and have been correlated with increased tumor aggressiveness and invasiveness. The nuclear factor-κB (NF-κB) is overexpressed in a subset of HER2-positive breast cancers and its upregulation has been associated with the metastatic potential of HER2-overexpressing tumors. The present study aimed at determining the potential of plumbagin, a naturally occurring naphthoquinone, to inhibit the invasion of HER2-overexpressing breast cancer cells and determine the involvement of NF-κB inhibition in plumbagin-mediated cell invasion suppression. In the present research we showed that plumbagin inhibited the transcriptional activity of NF-κB in HER2-positive breast cancer cells. The suppression of NF-κB activation corresponded with the inhibition of NF-κB p65 phosphorylation and downregulation of NF-κB-regulated matrix metalloproteinase 9 (MMP-9) expression. Plumbagin suppressed the invasion of HER2-overexpressing breast cancer cells and the inhibition of cell invasion was associated with the ability of plumbagin to inhibit NF-κB transcriptional activity. The silencing of NF-κB p65 increased the sensitivity of HER2-overexpressing breast cancer cells to plumbagin-induced cell invasion inhibition. NF-κB inhibition was associated with IκB kinase α (IKKα) activity suppression and inhibition of IκBα phosphorylation and degradation. The knockdown of IKKα resulted in increased sensitivity of HER2-positive cells to plumbagin-induced suppression of NF-κB transcriptional activity and expression of MMP-9. In conclusion, plumbagin inhibits the invasion of HER2-overexpressing breast cancer cells through the inhibition of IKKα-mediated NF-κB activation and downregulation of NF-κB-regulated MMP-9 expression.

A new form of amphotericin B - the complex with copper (II) ions - downregulates sTNFR1 shedding and changes the activity of genes involved in TNF-induced pathways: AmB-Cu2+ downregulates sTNFR1 shedding and changes the activity of genes involved in TNF-induced pathways

BACKGROUND

A new form of amphotericin B (AmB)- complex with copper (II) ions (AmB-Cu²⁺) - is less toxic to human renal cells. Cytokines, including Tumor Necrosis Factor (TNF), are responsible for nephrotoxicity observed in patients treated with AmB. Another problem during therapy is the occurrence of oxidized forms of AmB (AmB-ox) in patients' circulation. To elucidate the molecular mechanism responsible for the reduction of the toxicity of AmB-Cu²⁺, we evaluated the expression of genes encoding TNF and its receptors alongside encoding proteins involved in TNF-induced signalization.

METHODS

Renal cells (RPTECs) were treated with AmB, AmB-Cu²⁺ or AmB-ox. The expression of TNF and its receptors was evaluated by ELISA tests and real-time RT-qPCR. The expression of TNF-related genes was appointed using oligonucleotide microarrays.

RESULTS

Only sTNFR1 was detected, and its level was lower in AmB-Cu²⁺- and AmB-ox-treated cells. TNFR1 mRNA was downregulated in AmB-ox, while TNFR2 mRNA was upregulated in AmB and AmB-Cu²⁺. Several changes in the expression of TNF-related genes coincided with changes in the expression of TNF receptors.

CONCLUSIONS

The lower toxicity of AmB-Cu²⁺ could result from the changes in the expression of TNF receptors, which coincided with the changes in the expression of genes encoding proteins involved in TNF-induced pathways. This situation might subsequently result in a changes in intracellular signalization and influence the toxicity of tested forms of AmB on renal cells.

Toxicogenomics of Phenylhydrazine Induced Hematotoxicity and its Attenuation by Plumbagin from Plumbago zeylanica

BACKGROUND

High regenerative and proliferative capacity of blood and its components renders it to be at higher risk of adverse drug reactions (ADRs) which are manifested in several treatment regimens against various ailments such as cancers, viral diseases, and several metabolic disorders.

OBJECTIVE

It is prudent to come up with some therapeutic entity that can prevent this damage and protects the blood from these ADRs.

MATERIALS AND METHODS

We examined protective effects of Plumbago zeylanica (PZ) and its active constituent plumbagin (PL) on Sprague Dawley (SD) rats using a phenylhydrazine (Phz) induced hematotoxicity model. Hemoglobin (Hgb), red blood cells (RBCs), mean corpuscular volume, mean corpuscular Hgb (MCH), MCH concentration (MCHC), leukocytes and platelets were studied. Anti-oxidant enzymes superoxide dismutases 2 and 3 (SODs) and nuclear erythroid 2 p45-related factor 1 and 2 (Nfer-1 and 2) were also studied using quantitative real-time polymerase chain reaction (PCR).

RESULTS

In Phz treated rats, the positive hematotoxic response was obtained in terms of deviated endpoints of blood indices. In PLtreated groups protective response was obtained in terms of normal endpoints of blood indices. In PCR studies, we observed the similar trend. Thus, it can be postulated that PL exerts its protective effects via modulation of anti-oxidant enzymes.

CONCLUSION

The study proves that PL can be employed against combatting the ADRs associated with several therapeutic treatment regimens. Similar studies employing such pharmacological entities and their combinations may further prove to be effective against ADRs, especially in the context of blood cells.

SUMMARY

Hematotoxicity is generally encountered in various therapeutic regimens as ADRs (Adverse Drug Reactions). Plumbagin, an active constituent of plant Plumbago zeylanica is tested for its anti-hematotoxic potential in Phenylhydrazine induced hematotoxicity model in Sprague dawley rats. In vivo, in-vitro and molecular studies confirmed the peremptory actions of PL. It was revealed in our studies that the anti-hematotoxic actions of Plumbagin are due to its capacity to modulate anti-oxidant enzyme system.

CRM1 inhibitor S109 suppresses cell proliferation and induces cell cycle arrest in renal cancer cells

Abnormal localization of tumor suppressor proteins is a common feature of renal cancer. Nuclear export of these tumor suppressor proteins is mediated by chromosome region maintenance-1 (CRM1). Here, we investigated the antitumor eff ects of a novel reversible inhibitor of CRM1 on renal cancer cells. We found that S109 inhibits the CRM1-mediated nuclear export of RanBP1 and reduces protein levels of CRM1. Furthermore, the inhibitory eff ect of S109 on CRM1 is reversible. Our data demonstrated that S109 signifi cantly inhibits proliferation and colony formation of renal cancer cells. Cell cycle assay showed that S109 induced G1-phase arrest, followed by the reduction of Cyclin D1 and increased expression of p53 and p21. We also found that S109 induces nuclear accumulation of tumor suppressor proteins, Foxo1 and p27. Most importantly, mutation of CRM1 at Cys528 position abolished the eff ects of S109. Taken together, our results indicate that CRM1 is a therapeutic target in renal cancer and the novel reversible CRM1 inhibitor S109 can act as a promising candidate for renal cancer therapy.

Novel reversible selective inhibitor of CRM1 for targeted therapy in ovarian cancer

BACKGROUND

Ovarian cancer represents the most fatal type of gynecological malignancies. Unfortunately, there are still no effective targeted treatment strategies for ovarian cancer. Overexpression of CRM1 has been correlated with poor prognosis of patients with ovarian cancer.

AIM

In this study, we investigated the antitumor effects of a novel reversible inhibitor of CRM1 in ovarian cancer cells.

METHODS

The effects of S109 on proliferation was detected by CCK-8, EdU, clonogenic assay. The protein expression were determined by Western blot. The subcellular localization of RanBP1 was analyzed by immunofluorescence microscopy assay.

RESULTS

We demonstrated that S109 could induce nuclear accumulation of RanBP1, a canonical biomarker for CRM1 inhibition. This effect was clearly reversible in the majority of the cells, whereas the inhibitory effect of LMB could not be reversed. Our data reveal that treatment with S109 results in decrease in proliferation and colonogenic capacity of ovarian cancer cells by arresting cell cycle. Mechanistically, S109 treatment increase the expression of the cyclin-dependent kinase inhibitor p21, while it reduced the expression of cell cycle promoting proteins, Cyclin D1 and Cyclin B. CRM1 level itself was also down-regulated following S109 treatment. Furthermore, the nuclei of cells incubated with S109 accumulated tumor suppressor proteins (Foxo1, p27 and IκB-α). More importantly, Cys528 mutation of CRM1 abolished the ability of S109 to block proliferation of ovarian cancer cells.

CONCLUSIONS

Together, our study identifies CRM1 as a valid target in ovarian cancer and provides a basis for the development of S109 in ovarian cancer.

Novel reversible selective inhibitor of nuclear export shows that CRM1 is a target in colorectal cancer cells

Colorectal cancer arises via a multistep carcinogenic process and the deregulation of multiple pathways. Thus, the simultaneous targeting of multiple pathways may be a promising therapeutic approach for colorectal treatment. CRM1 is an attractive cancer drug target, because it can regulate multiple pathways and tumor suppressor proteins. In this study, we investigated the anti-tumor activity of a novel reversible CRM1 inhibitor S109 in colorectal cancer. Our data demonstrate that S109 inhibits proliferation and induces cell cycle arrest in colorectal cancer cells. Mechanistically, we demonstrate that the activity of S109 is associated with the nuclear retention of major tumor suppress proteins. Furthermore, the Cys528 mutation of CRM1 prevented the ability of S109 to block nuclear export and inhibit the proliferation of colorectal cancer cells. Interestingly, S109 decreased the CRM1 protein level via proteasomal pathway. We argue that reversible CRM1 inhibitors but not irreversible inhibitors can induce the degradation of CRM1, because the dissociation of reversible inhibitors of CRM1 changes the conformation of CRM1. Taken together, these findings demonstrate that CRM1 is a valid target for the treatment of colorectal cancer and provide a basis for the development of S109 therapies for colorectal cancer.