Shikonin Inhibites Migration and Invasion of Thyroid Cancer Cells by Downregulating DNMT1

A review on recent advances in assays for DNMT1: a promising diagnostic biomarker for multiple human cancers

The abnormal expression of human DNA methyltransferases (DNMTs) is closely related with the occurrence and development of a wide range of human cancers. DNA (cytosine-5)-methyltransferase-1 (DNMT1) is the most abundant human DNA methyltransferase and is mainly responsible for genomic DNA methylation patterns. Abnormal expression of DNMT1 has been found in many kinds of tumors, and DNMT1 has become a valuable target for the diagnosis and drug therapy of diseases. Nowadays, DNMT1 has been found to be involved in multiple cancers such as pancreatic cancer, breast cancer, bladder cancer, lung cancer, gastric cancer and other cancers. In order to achieve early diagnosis and for scientific research, various analytical methods have been developed for qualitative or quantitative detection of low-abundance DNMT1 in biological samples and human tumor cells. Herein, we provide a brief explication of the research progress of DNMT1 involved in various cancer types. In addition, this review focuses on the types, principles, and applications of DNMT1 detection methods, and discusses the challenges and potential future directions of DNMT1 detection.

METTL16 inhibits papillary thyroid cancer tumorigenicity through m6A/YTHDC2/SCD1-regulated lipid metabolism

Papillary thyroid carcinoma (PTC) stands as the leading cancer type among endocrine malignancies, and there exists a strong correlation between thyroid cancer and obesity. However, the clinical significance and molecular mechanism of lipid metabolism in the development of PTC remain unclear. In this study, it was demonstrated that the downregulation of METTL16 enhanced lipid metabolism and promoted the malignant progression of PTC. METTL16 was expressed at lower levels in PTC tissues because of DNMT1-mediated hypermethylation of its promoter. Loss- and gain-of-function studies clarified the effects of METTL16 on PTC progression. METTL16 overexpression increased the abundance of m6A in SCD1 cells, increasing RNA decay via the m6A reader YTHDC2. The SCD1 inhibitor A939572 inhibited growth and slowed down lipid metabolism in PTC cells. These results confirm the crucial role of METTL16 in restraining PTC progression through SCD1-activated lipid metabolism in cooperation with YTHDC2. This suggests that the combination of METTL16 and anti-SCD1 blockade might constitute an effective therapy for PTC.

DNMT1/DNMT3a-mediated promoter hypermethylation and transcription activation of ICAM5 augments thyroid carcinoma progression

Promoter methylation is one of the most studied epigenetic modifications and it is highly relevant to the onset and progression of thyroid carcinoma (THCA). This study investigates the promoter methylation and expression pattern of intercellular adhesion molecule 5 (ICAM5) in THCA. CpG islands with aberrant methylation pattern in THCA, and the expression profiles of the corresponding genes in THCA, were analyzed using bioinformatics. ICAM5 was suggested to have a hypermethylation status, and it was highly expressed in THCA tissues and cells. Its overexpression promoted proliferation, mobility, and tumorigenic activity of THCA cells. As for the downstream signaling, ICAM5 was found to activate the MAPK/ERK and MAPK/JNK signaling pathways. Either inhibition of ERK or JNK blocked the oncogenic effects of ICAM5. DNA methyltransferases 1 (DNMT1) and DNMT3a were found to induce promoter hypermethylation of ICAM5 in THCA cells. Knockdown of DNMT1 or DNMT3a decreased the ICAM5 expression and suppressed malignant properties of THCA cells in vitro and in vivo, which were, however, restored by further artificial ICAM5 overexpression. Collectively, this study reveals that DNMT1 and DNMT3a mediates promoter hypermethylation and transcription activation of ICAM5 in THCA, which promotes malignant progression of THCA through the MAPK signaling pathway.

Local administration of shikonin improved the overall survival in orthotopic murine glioblastoma models with temozolomide resistance

BACKGROUND

Glioblastoma is a type of intracranial malignancy. Shikonin, a Chinese traditional medicine, has been shown to have anti-tumor efficacy toward human glioblastoma cells in vitro. However, shikonin cannot easily cross the blood-brain barrier. To address this issue, we evaluated the anti-tumor effects of direct intracranial infusion of shikonin in in vivo orthotopic syngeneic murine glioblastoma models using C57BL/6 mice.

MATERIALS AND METHODS

The cytotoxic effects of shikonin against murine glioblastoma cells, SB28 and CT-2A, were reported resistance to temozolomide, were evaluated using an allophycocyanin-conjugated annexin V and propidium iodide assay with flow cytometry. Impedance-based real-time cell analysis (RTCA) was used to analyze the inhibitory effects of shikonin on growth and proliferation. To evaluate the anti-tumor activity of shikonin in vivo, we used orthotopic syngeneic murine glioblastoma models with SB28 and CT-2A cells.

RESULTS

In flow cytometry-based cytotoxic assays, shikonin induced apoptosis. RTCA indicated that shikonin decreased the cell index of murine glioblastoma cells, SB28 and CT-2A, in a dose-dependent manner (p < 0.0001 for both cell lines), while temozolomide did not (p = 0.91 and 0.82, respectively). In murine glioblastoma models, SB28 and CT-2A, direct intracranial infusion of shikonin, as a local chemotherapy, improved the overall survival of mice in a dose-dependent manner compared with control groups (p < 0.0001 and p = 0.02, respectively). While temozolomide did not (p = 0.48 and 0.52, respectively).

CONCLUSIONS

The direct intracranial infusion of shikonin has potential as a local therapy for patients with glioblastoma.

Shikonin Induces ROS-Dependent Apoptosis Via Mitochondria Depolarization and ER Stress in Adult T Cell Leukemia/Lymphoma

Adult T cell leukemia/lymphoma (ATLL) is an aggressive T-cell malignancy that develops in some elderly human T-cell leukemia virus (HTVL-1) carriers. ATLL has a poor prognosis despite conventional and targeted therapies, and a new safe and efficient therapy is required. Here, we examined the anti-ATLL effect of Shikonin (SHK), a naphthoquinone derivative that has shown several anti-cancer activities. SHK induced apoptosis of ATLL cells accompanied by generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential, and induction of endoplasmic reticulum (ER) stress. Treatment with a ROS scavenger, N-acetylcysteine (NAC), blocked both loss of mitochondrial membrane potential and ER stress, and prevented apoptosis of ATLL cells, indicating that ROS is an upstream trigger of SHK-induced apoptosis of ATLL cells through disruption of the mitochondrial membrane potential and ER stress. In an ATLL xenografted mouse model, SHK treatment suppressed tumor growth without significant adverse effects. These results suggest that SHK could be a potent anti-reagent against ATLL.

DNA methylation and cancer: transcriptional regulation, prognostic, and therapeutic perspective

DNA methylation is one among the major grounds of cancer progression which is characterized by the addition of a methyl group to the promoter region of the gene thereby causing gene silencing or increasing the probability of mutations; however, in bacteria, methylation is used as a defense mechanism where DNA protection is by addition of methyl groups making restriction enzymes unable to cleave. Hypermethylation and hypomethylation both pose as leading causes of oncogenesis; the former being more frequent which occurs at the CpG islands present in the promoter region of the genes, whereas the latter occurs globally in various genomic sequences. Reviewing methylation profiles would help in the detection and treatment of cancers. Demethylation is defined as preventing methyl group addition to the cytosine DNA base which could cause cancers in case of global hypomethylation, however, upon further investigation; it could be used as a therapeutic tool as well as for drug design in cancer treatment. In this review, we have studied the molecules that induce and enzymes (DNMTs) that bring about methylation as well as comprehend the correlation between methylation with transcription factors and various signaling pathways. DNA methylation has also been reviewed in terms of how it could serve as a prognostic marker and the various therapeutic drugs that have come into the market for reversing methylation opening an avenue toward curing cancers.

Developing an m5C regulator-mediated RNA methylation modification signature to predict prognosis and immunotherapy efficacy in rectal cancer

Background

Currently, a very small number of patients with colorectal cancer (CRC) respond to immune checkpoint inhibitor (ICI) treatment. Therefore, there is an urgent need to investigate effective biomarkers to determine the responsiveness to ICI treatment. Recently, aberrant 5-methylcytosine (m⁵C) RNA modification has emerged as a key player in the pathogenesis of cancer. Thus, we aimed to explore the predictive signature based on m⁵C regulator-related genes for characterizing the immune landscapes and predicting the prognosis and response to therapies.

Methods

The Cancer Genome Atlas (TCGA) cohort was used as the training set, while GEO data sets, real-time quantitative PCR (RT-qPCR) analysis from paired frozen tissues, and immunohistochemistry (IHC) data from tissue microarray (TMA) were used for validation. We constructed a novel signature based on three m⁵C regulator-related genes in patients with rectal adenocarcinoma (READ) using a least absolute shrinkage and selection operator (LASSO)-Cox regression and unsupervised consensus clustering analyses. Additionally, we correlated the three-gene signature risk model with the tumor immune microenvironment, immunotherapy efficiency, and potential applicable drugs.

Results

The m⁵C methylation-based signature was an independent prognostic factor, where low-risk patients showed a stronger immunoreactivity phenotype and a superior response to ICI therapy. Conversely, the high-risk patients had enriched pathways of cancer hallmarks and presented immune-suppressive state, which demonstrated that they are more insensitive to immunotherapy. Additionally, the signature markedly correlated with drug susceptibility.

Conclusions

We developed a reliable m⁵C regulator-based risk model to predict the prognosis, clarify the molecular and tumor microenvironment status, and identify patients who would benefit from immunotherapy or chemotherapy. Our study could provide vital guidance to improve prognostic stratification and optimize personalized therapeutic strategies for patients with rectal cancer.

Shikonin inhibits the proliferation of cervical cancer cells via FAK/AKT/GSK3β signalling

Cervical cancer is one of the most lethal malignancies of the female reproductive system. Shikonin, a naphthoquinone pigment extracted from the traditional medicinal herb, Lithospermum erythrorhizon, has been demonstrated to exert significant inhibitory effects on a variety of tumours in vitro and in vivo. In the present study, the effects of shikonin on cervical cancer and the underlying mechanisms were investigated. The effects of shikonin on the viability on HeLa and SiHa cervical cancer cells was examined using cell counting kit (CCK-8) and colony formation assays. Immunofluorescence assay was performed to detect the levels of the proliferation-related protein, Ki67. Western blot analysis was utilized to measure the phosphorylated and total expression levels of proteins, including focal adhesion kinase (FAK), AKT, and glycogen synthase kinase 3β (GSK3β). Cell migration was determined by using wound healing assay. Metastasis-associated 1 (MTA1), TGFβ1 and VEGF mRNA expression levels were determined using reverse transcription-quantitative PCR. It was demonstrated that, shikonin inhibited cervical cancer cell proliferation and migration. The data of the present study revealed that shikonin inhibited the proliferation of HeLa and SiHa cells in a concentration- and time-dependent manner. Mechanistically, shikonin blocked the proliferation of cervical cancer cells by downregulating the phosphorylation of FAK, AKT and GSK3β induced by EGF. In addition, shikonin significantly suppressed cell migration and reduced the expression of migration-related proteins, including MTA1, TGFβ1 and VEGF. On the whole, the present study demonstrates that shikonin may exert an inhibitory effect on the cervical cancer cell proliferation and migration through the FAK/AKT/GSK3β signaling pathway. These findings suggest that shikonin may function as a potential therapeutic drug for the treatment of cervical cancer.

Looking at Thyroid Cancer from the Tumor-Suppressor Genes Point of View

Thyroid cancer is the most frequent endocrine malignancy and accounts for approximately 1% of all diagnosed cancers. A variety of mechanisms are involved in the transformation of a normal tissue into a malignant one. Loss of tumor-suppressor gene (TSG) function is one of these mechanisms. The normal functions of TSGs include cell proliferation and differentiation control, genomic integrity maintenance, DNA damage repair, and signaling pathway regulation. TSGs are generally classified into three subclasses: (i) gatekeepers that encode proteins involved in cell cycle and apoptosis control; (ii) caretakers that produce proteins implicated in the genomic stability maintenance; and (iii) landscapers that, when mutated, create a suitable environment for malignant cell growth. Several possible mechanisms have been implicated in TSG inactivation. Reviewing the various TSG alteration types detected in thyroid cancers may help researchers to better understand the TSG defects implicated in the development/progression of this cancer type and to find potential targets for prognostic, predictive, diagnostic, and therapeutic purposes. Hence, the main purposes of this review article are to describe the various TSG inactivation mechanisms and alterations in human thyroid cancer, and the current therapeutic options for targeting TSGs in thyroid cancer.

Shikonin inhibited glycolysis and sensitized cisplatin treatment in non-small cell lung cancer cells via the exosomal pyruvate kinase M2 pathway

The active ingredient of the traditional Chinese medicine comfrey is shikonin, a naphthoquinone compound. The focus of this study was to investigate the effect of shikonin on the proliferation, invasion, migration, and chemoresistance of non-small cell lung cancer (NSCLC) cells, and to explore its underlying molecular biological mechanisms. The results show that shikonin inhibited the viability, proliferation, invasion, and migration of NSCLC cells A549 and PC9, and induced apoptosis. As the inhibitor of pyruvate kinase M2 (PKM2), a key enzyme in glycolysis, shikonin inhibited glucose uptake and the production of lactate, the final metabolite of aerobic glycolysis. In vivo chemotherapeutic assay showed that shikonin reduced the tumor volume and weight in NSCLC mice model and increased the sensitivity to cisplatin chemotherapy. Histoimmunology experiments showed the combination of shikonin and cisplatin downregulated the expression of PKM2 and its transcriptionally regulated downstream gene glucose transporter 1 (Glut1) in tumor tissue. In an assessment of glucose metabolism, micro-PET/CT data showed a combination of shikonin and cisplatin inhibited the fluorodeoxy glucose (¹⁸F-FDG) uptake into tumor. Since exosomal PKM2 affected the sensitivity to cisplatin in NSCLC cells, we also demonstrated shikonin could inhibit exosome secretion and exosomal PKM2 through the administration of exosomal inhibitor GW4869. Furthermore, shikonin sensitized cisplatin treatment by reducing the extracellular secretion of exosomal PKM2. In conclusion, we suggest that shikonin not only inhibits PKM2 intracellularly but also reduces glycolytic flux and increases cisplatin sensitivity through the exosomal pathway.

Emerging therapeutic role of Prunella vulgaris in thyroid disease

Thyroid disease is characterized by unusual levels of thyroid hormones, which results in either hyperthyroidism or hypothyroidism. The pathology of a particular type or stage of thyroid disease is very complicated, and always linked to a variety of biological functions. Although the mortality rate is not high, thyroid dysfunction could lead to metabolic and immunological disorders that can subsequently cause discomfort. To date, many drugs are suggested to have curative effects on thyroid disease, however, drug toxicity and long treatment periods encourage the search for more promising ones. Prunella vulgaris L. (Labiatae) is a popular herb that has shown great potential for improving human immunity and organ protection. It has been extensively used in the treatment of many diseases but its ability to treat specific diseases has not been fully reported. In this review, a literature search regarding herbs and herbal recipes for treating thyroid disease were carried out, organized, and summarized. In addition, this study conducted a literature search on the current situation and progress of P. vulgaris treatment for various diseases. Finally, this study discussed studies regarding P. vulgaris treatment of goiter, and the mechanism of treatment through the regulation of apoptosis. Accordingly, a combination therapy of herbs and Western medicine can provide significant therapeutic effects in the clinical treatment of thyroid disease. Furthermore, the association between P. vulgaris and various diseases suggests that P. vulgaris is rich in a variety of active substances that can fight oxidation and participate in the regulation of apoptosis, thus having a protective effect on the thyroid. Here, a comprehensive literature review regarding the application of herbs or herbal recipes in the treatment of thyroid disease was presented. It is concluded that there is strong evidence for further research regarding the use of P. vulgaris in the treatment of thyroid diseases.

DNA Methylation Malleability and Dysregulation in Cancer Progression: Understanding the Role of PARP1

Mammalian genomic DNA methylation represents a key epigenetic modification and its dynamic regulation that fine-tunes the gene expression of multiple pathways during development. It maintains the gene expression of one generation of cells; particularly, the mitotic inheritance of gene-expression patterns makes it the key governing mechanism of epigenetic change to the next generation of cells. Convincing evidence from recent discoveries suggests that the dynamic regulation of DNA methylation is accomplished by the enzymatic action of TET dioxygenase, which oxidizes the methyl group of cytosine and activates transcription. As a result of aberrant DNA modifications, genes are improperly activated or inhibited in the inappropriate cellular context, contributing to a plethora of inheritable diseases, including cancer. We outline recent advancements in understanding how DNA modifications contribute to tumor suppressor gene silencing or oncogenic-gene stimulation, as well as dysregulation of DNA methylation in cancer progression. In addition, we emphasize the function of PARP1 enzymatic activity or inhibition in the maintenance of DNA methylation dysregulation. In the context of cancer remediation, the impact of DNA methylation and PARP1 pharmacological inhibitors, and their relevance as a combination therapy are highlighted.

Shikonin, a naphthalene ingredient: Therapeutic actions, pharmacokinetics, toxicology, clinical trials and pharmaceutical researches

BACKGROUND

Shikonin is one of the major phytochemical components of Lithospermum erythrorhizon (Purple Cromwell), which is a type of medicinal herb broadly utilized in traditional Chinese medicine. It is well established that shikonin possesses remarkable therapeutic actions on various diseases, with the underlying mechanisms, pharmacokinetics and toxicological effects elusive. Also, the clinical trial and pharmaceutical study of shikonin remain to be comprehensively delineated.

PURPOSE

The present review aimed to systematically summarize the updated knowledge regarding the therapeutic actions, pharmacokinetics, toxicological effects, clinical trial and pharmaceutical study of shikonin.

METHODS

The information contained in this review article were retrieved from some authoritative databases including Web of Science, PubMed, Google scholar, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database and so on, till August 2021.

RESULTS

Shikonin exerts multiple therapeutic efficacies, such as anti-inflammation, anti-cancer, cardiovascular protection, anti-microbiomes, analgesia, anti-obesity, brain protection, and so on, mainly by regulating the NF-κB, PI3K/Akt/MAPKs, Akt/mTOR, TGF-β, GSK3β, TLR4/Akt signaling pathways, NLRP3 inflammasome, reactive oxygen stress, Bax/Bcl-2, etc. In terms of pharmacokinetics, shikonin has an unfavorable oral bioavailability, 64.6% of the binding rate of plasma protein, and enhances some metabolic enzymes, particularly including cytochrome P450. In regard to the toxicological effects, shikonin may potentially cause nephrotoxicity and skin allergy. The above pharmacodynamics and pharmacokinetics of shikonin have been validated by few clinical trials. In addition, pharmaceutical innovation of shikonin with novel drug delivery system such as nanoparticles, liposomes, microemulsions, nanogel, cyclodextrin complexes, micelles and polymers are beneficial to the development of shikonin-based drugs.

CONCLUSIONS

Shikonin is a promising phytochemical for drug candidates. Extensive and intensive explorations on shikonin are warranted to expedite the utilization of shikonin-based drugs in the clinical setting.

Natural Bioactive Compounds Targeting Epigenetic Pathways in Cancer: A Review on Alkaloids, Terpenoids, Quinones, and Isothiocyanates

Cancer is one of the most complex and systemic diseases affecting the health of mankind, causing major deaths with a significant increase. This pathology is caused by several risk factors, of which genetic disturbances constitute the major elements, which not only initiate tumor transformation but also epigenetic disturbances which are linked to it and which can induce transcriptional instability. Indeed, the involvement of epigenetic disturbances in cancer has been the subject of correlations today, in addition to the use of drugs that operate specifically on different epigenetic pathways. Natural molecules, especially those isolated from medicinal plants, have shown anticancer effects linked to mechanisms of action. The objective of this review is to explore the anticancer effects of alkaloids, terpenoids, quinones, and isothiocyanates.

Uncovering the Association Between m5C Regulator-Mediated Methylation Modification Patterns and Tumour Microenvironment Infiltration Characteristics in Hepatocellular Carcinoma

Background: 5-Methylcytosine (m⁵C) plays essential roles in hepatocellular carcinoma (HCC), but the association between m⁵C regulation and immune cell infiltration in HCC has not yet been clarified.

Methods: In this study, we analysed 371 patients with HCC from The Cancer Genome Atlas (TCGA) database, and the expression of 13 m⁵C regulators was investigated. Additionally, gene set variation analysis (GSVA), unsupervised clustering analysis, single-sample gene set enrichment analysis (ssGSEA), correlation analysis, and immunohistochemical (IHC) staining were performed.

Results: Among the 371 patients, 41 had mutations in m⁵C regulators, the frequency of which was 11.26%. Compared with normal hepatic tissues, the expression of m⁵C regulators with copy number variations (CNVs) expansion was significantly higher than that in HCC tissues. Then, we identified three m⁵C modification patterns that had obvious tumour microenvironment (TME) cell infiltration characteristics. The prognostic analysis of the three major m⁵C modification subtypes showed that Cluster-2 had a clear survival advantage over the others. In addition, we found that DNMT1 was highly expressed in tumour tissues compared with normal tissues in a tissue microarray (TMA) and that it was positively correlated with many TME-infiltrating immune cells. High expression of the m⁵C regulator DNMT1 was related to a poor prognosis in patients with HCC. Furthermore, we developed three distinct Immu-clusters. Importantly, mRNAs related to the transcription of growth factor β (TGF-β)/EMT pathway were significantly up-regulated in Immu-cluster 2, indicating that this cluster is considered to be the immune rejection phenotype. Immu-cluster 3 showed elevated expression of mRNAs related to immune checkpoint genes.

Conclusion: Our work revealed the association between m⁵C modification and immune regulators in the TME. These findings also suggest that DNMT1 has great potential as a prognostic biomarker and therapeutic target for HCC.

Programmed cell death, redox imbalance, and cancer therapeutics

Cancer cells are disordered by nature and thus featured by higher internal redox level than healthy cells. Redox imbalance could trigger programmed cell death if exceeded a certain threshold, rendering therapeutic strategies relying on redox control a possible cancer management solution. Yet, various programmed cell death events have been consecutively discovered, complicating our understandings on their associations with redox imbalance and clinical implications especially therapeutic design. Thus, it is imperative to understand differences and similarities among programmed cell death events regarding their associations with redox imbalance for improved control over these events in malignant cells as well as appropriate design on therapeutic approaches relying on redox control. This review addresses these issues and concludes by bringing affront cold atmospheric plasma as an emerging redox controller with translational potential in clinics.

Shikonin inhibits growth, invasion and glycolysis of nasopharyngeal carcinoma cells through inactivating the phosphatidylinositol 3 kinase/AKT signal pathway

Nasopharyngeal carcinoma (NPC) is a malignant tumor which is commonly found in East Asia and Africa. The present clinical treatment of NPC is still mainly based on chemotherapeutics and is prone to drug resistance and adverse reactions. Shikonin has been demonstrated to play the antitumor effect in various cancers. However, the specific effects and related regulatory mechanism of Shikonin in NPC have not been clearly declared yet. Cell viability was valued through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation was detected through colony formation assay and Bromodeoxyuridine (BrdU) assay. Hochest 33258 staining was used to value cell apoptosis. Cell migration and invasion were valued through wound healing and transwell invasion assay, respectively. Glucose uptake, lactate release, ATP level and pyruvate kinase M2 isoform (PKM2) activity were measured using corresponding assay kits. Western blotting was used to examine the expression of proteins related to cell proliferation, cell apoptosis, cell migration and the phosphatidylinositol 3 kinase (PI3K)/AKT signal pathway. We found that Shikonin treatment effectively suppressed cell proliferation and induced obvious cell apoptosis compared with the control. Besides, Shikonin treatment suppressed cell migration and invasion effectively. The detection about glycolysis showed that Shikonin treatment suppressed cell glucose uptake, lactate release and ATP level. The activity of PKM2 was also largely inhibited by Shikonin. Further study revealed that the PI3K/AKT signal pathway was inactivated by Shikonin treatment. In addition, the inducer of the PI3K/AKT signal pathway largely abolished the antitumor effect of Shikonin on cell proliferation, cell apoptosis, cell mobility and aerobic glycolysis in NPC cells. Shikonin inhibits growth and invasion of NPC cells through inactivating the PI3K/AKT signal pathway.

Shikonin inhibits the Warburg effect, cell proliferation, invasion and migration by downregulating PFKFB2 expression in lung cancer

Lung cancer is one of the most lethal diseases and therefore poses a significant threat to human health. The Warburg effect, which is the observation that cancer cells predominately produce energy through glycolysis, even under aerobic conditions, is a hallmark of cancer. 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2 (PFKFB) is an important regulator of glycolysis. Shikonin is a Traditional Chinese herbal medicine, which has been reported to exert antitumor effects. The present study aimed to investigate the anticancer activity of shikonin in lung cancer. Cell Counting Kit-8 (CCK-8) and colony formation assays were used to analyze proliferation in A549 and H446 cells. Wound healing and Transwell assays were used to measure migration and invasion in A549 and H446 cells. Cell apoptosis was analyzed using flow cytometry. Lactate levels, glucose uptake and cellular ATP levels were measured using their corresponding commercial kits. Western blotting was performed to analyze the protein expression levels of key enzymes involved in aerobic glucose metabolism. Reverse transcription-quantitative PCR was used to analyze the mRNA expression levels of PFKFB2. The results of the present study revealed that PFKFB2 expression levels were significantly upregulated in NSCLC tissues. Shikonin treatment decreased the proliferation, migration, invasion, glucose uptake, lactate levels, ATP levels and PFKFB2 expression levels and increased apoptosis in lung cancer cells in a dose-dependent manner. The overexpression of PFKFB2 increased the proliferation, migration, glucose uptake, lactate levels and ATP levels in lung cancer cells, while the knockdown of PFKFB2 expression exerted the opposite effects. Moreover, there were no significant differences in lung cancer cell migration, apoptosis, glucose uptake, lactate levels and ATP levels between cells with knocked down PFKFB2 expression or treated with shikonin and the knockdown of PFKFB2 in cells treated with shikonin. In conclusion, the results of the present study revealed that shikonin inhibited the Warburg effect and exerted antitumor activity in lung cancer cells, which was associated with the downregulation of PFKFB2 expression.

Shikonin Inhibits Cholangiocarcinoma Cell Line QBC939 by Regulating Apoptosis, Proliferation, and Invasion

This study was designed to clarify whether Shikonin causes proliferation, apoptosis, and invasion in cholangiocarcinoma cells and to investigate the mechanism of action. QBC939 cells were cultured with different doses of Shikonin, and then 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium assay was used to detect cell viability. Apoptosis of cells was detected using flow cytometry with Annexin V/propidium iodide (PI) assay after being stained with Hoechst 33242. The role of Shikonin on the invasive and metastasis ability was detected using Transwell invasion assay. Real-time polymerase chain reaction and Western blotting were used to detect the expression of caspase-3, caspase-8, epidermal growth factor receptor (EGFR), and matrix metalloproteinase (MMP)-9. Shikonin inhibited proliferation and invasive ability of QBC939 cells in a dose-dependent manner; at the same time, apoptosis of cells was also observed in a concentration-dependent fashion. Moreover, Annexin V/PI assay and Transwell invasion assay results indicated that Shikonin induced apoptosis and invasion inhibitory probably due to upregulation of caspase-3 and caspase-8 expression and downregulation of MMP-9 and EGFR expression in a concentration-dependent fashion. Shikonin could enhance apoptosis and inhibit proliferation and invasion of QBC939 cells; such biological behaviors mainly occurred via upregulating the expression of caspase-3 and caspase-8 and downregulating the expression of MMP-9 and EGFR.

Silencing of miR-152 contributes to DNMT1-mediated CpG methylation of the PTEN promoter in bladder cancer

AIM

Bladder cancer (BCa) is one of the most commonly occurring urological malignancy. DNA methylation mediated by DNA methyltransferase 1 (DNMT1) plays a crucial role in the physiological and pathological processes of cancer. However, the role of upstream regulatory factors and downstream target genes of DNA methylation mediated by DNMT1 needs further study in BCa. We aim to discover the upstream regulatory factor and downstream target gene of DNMT1, which form a signaling pathway to regulate the progression of BCa.

MAIN METHODS

DNMT1 expression in BCa tissues and cells was detected by qPCR and Western Blot. Balbc/nu/nu mice were used to determine the relationship between DNMT1 expression and tumor growth. CCK8, EdU, and transwell assays were employed to measure cell viability, proliferation, and migration respectively. RNA immunoprecipitation (RIP) assays and dual luciferase reporter assays were applied to determine the relationships among DNMT1, miR-152-3p and PTEN.

KEY FINDINGS

A significant up-regulation of DNMT1 in BCa tissues and cells, and silencing of DNMT1 expression inhibited the tumor growth in vivo. Knockdown of DNMT1 inhibited the cell growth and migration of BCa cells. miR-152-3p inhibited the DNMT1 and over-expression of DNMT1 restored the cellular function of miR-152-3p in BCa cells. DNMT1 regulated the phosphatase and tensin homolog (PTEN) expression via modulating the status of DNA methylation in the promoter of PTEN.

SIGNIFICANCE

This study confirmed the role and underlying mechanism of DNMT1-mediated DNA methylation and displayed a novel regulatory pathway miR-152/DNMT1/PTEN in BCa, thus, providing a potential diagnostic and therapeutic targets for BCa.

DNA Methyltransferases in Cancer: Biology, Paradox, Aberrations, and Targeted Therapy

DNA methyltransferases are an essential class of modifiers in epigenetics. In mammals, DNMT1, DNMT3A and DNMT3B participate in DNA methylation to regulate normal biological functions, such as embryo development, cell differentiation and gene transcription. Aberrant functions of DNMTs are frequently associated with tumorigenesis. DNMT aberrations usually affect tumor-related factors, such as hypermethylated suppressor genes and genomic instability, which increase the malignancy of tumors, worsen the prognosis for patients, and greatly increase the difficulty of cancer therapy. However, the impact of DNMTs on tumors is still controversial, and therapeutic approaches targeting DNMTs are still under exploration. Here, we summarize the biological functions and paradoxes associated with DNMTs and we discuss some emerging strategies for targeting DNMTs in tumors, which may provide novel ideas for cancer therapy.

Shikonin Inhibits Cancer Through P21 Upregulation and Apoptosis Induction

Shikonin is a natural naphthoquinone compound and has demonstrated potent anti-cancer activities; however, the underlying molecular mechanisms remained elusive. Here we report that Shikonin inhibited the growth of a wide range of human cancer cell lines, illustrating a broad anticancer effect. Mechanistically, we show that Shikonin arrested the cell cycle at the G2/M phase, inhibited the ERK-dependent cell growth signal, and induced cell death in both P53 wild type and mutant cancer cells, which collectively contributed to the growth inhibitory effect of Shikonin. A pan-apoptosis inhibitor largely suppressed Shikonin-induced cell death, suggesting an important role of apoptosis in this process. Intriguingly, Shikonin also activated autophagy and inhibition of autophagy by depleting critical autophagic genes further increased Shikonin-induced cell death, indicating a protective role of autophagy. In uncovering the molecular mechanisms underlying these effects of Shikonin, we found that Shikonin induced a robust upregulation of P21 independent of the P53 status, upregulated autophagy genes, as well as inhibited expression of genes required for cell growth. Using mouse tumor models, we confirmed the strong anticancer effect of Shikonin in vivo. Together, our data reveal a broad range of pharmacological functions of Shikonin, involving simultaneous growth inhibition, cell cycle arrest, autophagy activation and apoptosis induction through regulating expression of critical genes involved in these pathways. Our study may facilitate the development of Shikonin in cancer therapy as a single agent or in combination with other anticancer therapies.

Herbal Active Ingredients: An Emerging Potential for the Prevention and Treatment of Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) is the most common subtype of differentiated thyroid cancers in Asian coastal cities, where the patients have increased risk of potentially high or excessive iodine intake. Given the high metastasis and recurrence of patients with BRAF^V600E mutation, the mortality rate of thyroid cancer has recently shown an upward trend. A variety of therapies, including surgery, radiotherapy, and chemotherapy, have been used to treat thyroid cancer, but these therapies still have limitations, including postoperative complications, drug resistance, poor efficacy, or serious side effects. Recent studies have shown the potential of active ingredients derived from herbal medicine in inhibiting PTC via various cell signaling pathways. Some plant-derived compounds, such as apigenin, genistein, and curcumin, are also known to prevent and treat PTC. This article summarizes the recent advances in the structure-functional impact of anti-PTC active ingredients and their effects on PTC cells and tumor microenvironments with an emphasis on their challenges from basic research to clinical practice.

Competitive glucose metabolism as a target to boost bladder cancer immunotherapy

Bladder cancer - the tenth most frequent cancer worldwide - has a heterogeneous natural history and clinical behaviour. The predominant histological subtype, urothelial bladder carcinoma, is characterized by high recurrence rates, progression and both primary and acquired resistance to platinum-based therapy, which impose a considerable economic burden on health-care systems and have substantial effects on the quality of life and the overall outcomes of patients with bladder cancer. The incidence of urothelial tumours is increasing owing to population growth and ageing, so novel therapeutic options are vital. Based on work by The Cancer Genome Atlas project, which has identified targetable vulnerabilities in bladder cancer, immune checkpoint inhibitors (ICIs) have arisen as an effective alternative for managing advanced disease. However, although ICIs have shown durable responses in a subset of patients with bladder cancer, the overall response rate is only ~15-25%, which increases the demand for biomarkers of response and therapeutic strategies that can overcome resistance to ICIs. In ICI non-responders, cancer cells use effective mechanisms to evade immune cell antitumour activity; the overlapping Warburg effect machinery of cancer and immune cells is a putative determinant of the immunosuppressive phenotype in bladder cancer. This energetic interplay between tumour and immune cells leads to metabolic competition in the tumour ecosystem, limiting nutrient availability and leading to microenvironmental acidosis, which hinders immune cell function. Thus, molecular hallmarks of cancer cell metabolism are potential therapeutic targets, not only to eliminate malignant cells but also to boost the efficacy of immunotherapy. In this sense, integrating the targeting of tumour metabolism into immunotherapy design seems a rational approach to improve the therapeutic efficacy of ICIs.

Pharmacological properties and derivatives of shikonin-A review in recent years

Shikonin is the major bioactive component extracted from the roots of Lithospermum erythrorhizon which is also known as "Zicao" in Traditional Chinese Medicine (TCM). Recent studies have shown that shikonin demonstrates various bioactivities related to the treatment of cancer, inflammation, and wound healing. This review aimed to provide an updated summary of recent studies on shikonin. Firstly, many studies have demonstrated that shikonin exerts strong anticancer effects on various types of cancer by inhibiting cell proliferation and migration, inducing apoptosis, autophagy, and necroptosis. Shikonin also triggers Reactive Oxygen Species (ROS) generation, suppressing exosome release, and activate anti-tumor immunity in multiple molecular mechanisms. Examples of these effects include modulating the PI3K/AKT/mTOR and MAPKs signaling; inhibiting the activation of TrxR1, PKM2, RIP1/3, Src, and FAK; and regulating the expression of ERP57, MMPs, ATF2, C-MYC, miR-128, and GRP78 (Bip). Next, the anti-inflammatory and wound-healing properties of shikonin were also reviewed. Furthermore, several studies focusing on shikonin derivatives were reviewed, and these showed that, with modification to the naphthazarin ring or side chain, some shikonin derivatives display stronger anticancer activity and lower toxicity than shikonin itself. Our findings suggest that shikonin and its derivatives could serve as potential novel drug for the treatment of cancer and inflammation.

Promoter Methylation of Four Tumor Suppressor Genes in Human Papillary Thyroid Carcinoma

BACKGROUND & OBJECTIVE

Papillary thyroid cancer (PTC) is considered to be the most common type of thyroid malignancies. Epigenetic alteration, in which the chromatin conformation and gene expression change without changing the sequence of DNA, can occur in some tumor suppressor genes and oncogenes. Methylation is the most common type of epigenetic alterations that can be an excellent indicator of PTC invasive behavior.

METHODS

In this research, we determined the promoter methylation status of four tumor suppressor genes (SLC5A8, RASSF1, MGMT, and DNMT1) and compared the results of 55 PTC cases with 40 goiter patients. For methylation, we used the methylation-sensitive high resolution melting (MS-HRM) assay technique. The resulting graphs of each run were compared with those of 0%, 50%, and 100% methylated controls.

RESULTS

Our data showed that the promoter methylation of SLC5A8, Ras association domain family member 1(RASSF1), and MGMT were significantly different between PTC tissue and goiter with P-value less than 0.05. The most significant differences were observed in RASSF1; 77.2% of hyper-methylated PTC patients versus 15.6% hyper-methylated goiter samples (P<0.001).

CONCLUSION

RASSF1 promoter methylation can be a PTC genetic marker. RASSF1 promoter methylation is under the impact of the methyltransferase genes (DNMT1 and MGMT), protein expression, and promoter methylation.

Shikonin derivatives for cancer prevention and therapy

Phytochemicals gained considerable interest during the past years as source to develop new treatment options for chemoprevention and cancer therapy. Motivated by the fact that a majority of established anticancer drugs are derived in one way or another from natural resources, we focused on shikonin, a naphthoquinone with high potentials to be further developed as preventive or therapeutic drug to fight cancer. Shikonin is the major chemical component of Lithospermum erythrorhizon (Purple Cromwell) roots. Traditionally, the root extract has been applied to cure dermatitis, burns, and wounds. Over the past three decades, the anti-inflammatory and anticancer effects of root extracts, isolated shikonin as well as semi-synthetic and synthetic derivatives and nanoformulations have been described. In vitro and in vivo experiments were conducted to understand the effect of shikonin at cellular and molecular levels. Preliminary clinical trials indicate the potential of shikonin for translation into clinical oncology. Shikonin exerts additive and synergistic interactions in combination with established chemotherapeutics, immunotherapeutic approaches, radiotherapy and other treatment modalities, which further underscores the potential of this phytochemical to be integrated into standard treatment regimens.