PRDM1, a Tumor-Suppressor Gene, is Induced by Genkwadaphnin in Human Colon Cancer SW620 Cells

Daphne genkwa: Ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

Daphne genkwa, as a traditional medicine, is widely distributed in China, Korea and Vietnam. In China, the dried flower buds of this plant are named "Yuanhua". It has the ability to effectively promote urination, eliminate phlegm and alleviate cough, eliminate parasites and cure of scabies, with a broad spectrum of pharmacological effects and considerable clinical efficacy. This paper provides a summary and classification of the main chemical constituents of D. genkwa based on a review of relevant domestic and foreign literature. It also outlines the current research status of traditional clinical usage, pharmacological effects, and toxicity of D. genkwa. The aim is to provide a theoretical basis for further study of D. genkwa and its potential new clinical applications.

Yuanhuacin and Related Anti-Inflammatory and Anticancer Daphnane Diterpenes from Genkwa Flos—An Overview

The dried flower buds of the plant Daphne genkwa Sieb. et Zucc. have been largely used in traditional Chinese medicine for the treatment of inflammatory diseases. Numerous diterpenoids have been isolated from the Genkwa Flos (yuanhua in Chinese), including a series of daphnane-type diterpene designated as yuanhuacin (YC, often improperly designated as yuanhuacine) and analogues with a patronymic name. The series includes ten daphnane-type diterpenes: yuanhuacin, yuanhuadin (YD), yuanhuafin (YF), yuanhuagin (YG), yuanhuahin (YH), yuanhuajin (YJ), yuanhualin (YL), yuanhuamin (YM), yuanhuapin (YP), and yuanhuatin (YT). They are distinct from the rare flavonoid yuanhuanin. The series comprises several anticancer agents, such as the lead compound YC, which has revealed potent activity in vitro and in vivo against models of lung and breast cancers. The main signaling pathways implicated in the antitumor effects have been delineated. Protein kinase C is a key factor of activity for YC, but in general the molecular targets at the origin of the activity of these compounds remain little defined. Promising anticancer effects have been reported with analogues YD and YT, whereas compounds YF and YP are considered more toxic. The pharmacological activity of each compound is presented, as well as the properties of Genkwa Flos extracts. The potential toxic effects associated with the use of these compounds are also underlined.

Phytochemistry and Pharmacological Activities of the Diterpenoids from the Genus Daphne

There are abundant natural diterpenoids in the plants of the genus Daphne from the Thymelaeaceae family, featuring a 5/7/6-tricyclic ring system and usually with an orthoester group. So far, a total of 135 diterpenoids has been isolated from the species of the genus Daphne, which could be further classified into three main types according to the substitution pattern of ring A and oxygen-containing functions at ring B. A variety of studies have demonstrated that these compounds exert a wide range of bioactivities both in vitro and in vivo including anticancer, anti-inflammatory, anti-HIV, antifertility, neurotrophic, and cholesterol-lowering effects, which is reviewed herein. Meanwhile, the fascinating structure-activity relationship is also concluded in this review in the hope of providing an easy access to available information for the synthesis and optimization of efficient drugs.

6q deletion is frequent but unrelated to patient prognosis in breast cancer

BACKGROUND

Deletions involving the long arm of chromosome 6 have been reported to occur in breast cancer, but little is known about the clinical relevance of this alteration.

METHODS

We made use of a pre-existing tissue microarray with 2197 breast cancers and employed a 6q15/centromere 6 dual-labeling probe for fluorescence in situ (FISH) analysis RESULTS: Heterozygous 6q15 deletions were found in 202 (18%) of 1099 interpretable cancers, including 19% of 804 cancers of no special type (NST), 3% of 29 lobular cancers, 7% of 41 cribriform cancers, and 28% of 18 cancers with papillary features. Homozygous deletions were not detected. In the largest subset of NST tumors, 6q15 deletions were significantly linked to advanced tumor stage and high grade (p < 0.0001 each). 6q deletions were also associated with estrogen receptor negativity (p = 0.0182), high Ki67 proliferation index (p < 0.0001), amplifications of HER2 (p = 0.0159), CCND1 (p = 0.0069), and cMYC (p = 0.0411), as well as deletions of PTEN (p = 0.0003), 8p21 (p < 0.0001), and 9p21 (p = 0.0179). However, 6q15 deletion was unrelated to patient survival in all cancers, in NST cancers, or in subsets of cancers defined by the presence or absence of lymph-node metastases.

CONCLUSION

Our data demonstrate that 6q deletion is a frequent event in breast cancer that is statistically linked to unfavorable tumor phenotype and features of genomic instability. The absence of any prognostic impact argues against a clinical applicability of 6q15 deletion testing in breast cancer patients.

Pan-drug and drug-specific mechanisms of 5-FU, irinotecan (CPT-11), oxaliplatin, and cisplatin identified by comparison of transcriptomic and cytokine responses of colorectal cancer cells

Colorectal cancer (CRC) caused over 900,000 deaths worldwide in 2020. A majority of late-stage CRC patients are treated with 5-fluorouracil (5-FU) combined with either irinotecan (CPT-11), oxaliplatin, or both. Despite their widespread use, the mechanisms of efficacy and toxicity of these drugs remain incompletely understood. While previous work has investigated cellular responses to these agents individually, we directly compare the transcriptomic and cytokine profiles of HCT116 wild-type and p53-/- colorectal cancer cells treated with these drugs and report pan-drug, drug-specific, drug class-specific, p53-independent, and p53-dependent signatures. We observed downregulation of histone genes by 5-FU (that significantly correlates with improved survival in CRC patients) and upregulation of FOS and ATF3 by oxaliplatin (which may contribute to peripheral neuropathy). BTG2 was identified as a top gene upregulated by all four drugs, suggesting its critical role in the cellular response to chemotherapy in CRC. Soluble TRAILR2 (death receptor 5; DR5) is a decoy receptor for TRAIL, an apoptosis-inducing cytokine. TRAILR2 was down-regulated by oxaliplatin and 5-FU, was not affected by CPT-11, and was increased by cisplatin. There was an increase in IL-8 by oxaliplatin and increase in ferritin by cisplatin which may contribute to cancer cell survival. Novel drug-specific mechanisms of efficacy or toxicity identified in these signatures may be targeted with combination therapies or development of new targeted therapies. Together, the findings here contribute to our understanding of the molecular bases of efficacy and toxicity of chemotherapeutic agents often used for treatment of GI cancer such as CRC.

Analysis of Genetic Alterations Related to DNA Methylation in Testicular Germ Cell Tumors Based on Data Mining

Embryonal carcinoma (EC) and seminoma (SE) are both derived from germ cell neoplasia in situ but show big differences in growth patterns and clinical prognosis. Epigenetic regulation may play an important role in the development of EC and SE. This study investigated the DNA methylation-based genetic alterations between EC and SE by analyzing the datasets of mRNA expression and DNA methylation profiling. The datasets were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified between EC and SE by limma package in R environment. Gene function enrichment analysis of the DEGs was performed on the DAVID tool, the results of which suggested differences in capability of pluripotency and genomic stability between EC and SE. The minfi package and wANNOVAR tool were used to identify differentially methylated genes. A total of 37 genes were discovered with both mRNA expression and the accordant DNA methylation changes. The findings were verified by the sequencing data from The Cancer Genome Atlas database, and Kaplan-Meier survival analysis was performed. Finally, 5 genes (PRDM1, LMO2, FAM53B, HCN4, and FAM124B) were found that showed both low expression and high methylation in EC, and were significantly associated with relapse-free survival. The findings of methylation-based genetic features between EC and SE might be helpful in studying the role of DNA methylation in cancer development.

Daphnane-type diterpenes from genus Daphne and their anti-tumor activity

Daphnane-type diterpenenoids are the major biologically active constituents in the genus Daphne. We find that there are about 101 Daphnane-type diterpenes in this genus, most of those compounds show different degrees of inhibitory effect on various cancer cell. Some of them have been studied in depth and the potent molecular mechanisms might be associated with modulation of different cell-signaling pathways. In addition, some compounds of this type also can inhibit the synthesis of protein and DNA. Absolutely, the anti-tumor activity of Daphnane-type diterpenes is worthy of attention. Unfortunately, most of the current research on the activity of these compounds is focused on simple drug efficacy, and its in-depth mechanism research is far from enough. On the other point of view, there still exists wide growing space on the depth of these compounds.

TGF-β1-regulated miR-3691-3p targets E2F3 and PRDM1 to inhibit prostate cancer progression

Transforming growth factor-β1 (TGF-β1) acts as a tumor promoter in advanced prostate cancer (PCa). We speculated that microRNAs (miRNAs) that are inhibited by TGF-β1 might exert anti-tumor effects. To assess this, we identified several miRNAs downregulated by TGF-β1 in PCa cell lines and selected miR-3691-3p for detailed analysis as a candidate anti-oncogene miRNA. miR-3691-3p was expressed at significantly lower levels in human PCa tissue compared with paired benign prostatic hyperplasia tissue, and its expression level correlated inversely with aggressive clinical pathological features. Overexpression of miR-3691-3p in PCa cell lines inhibited proliferation, migration, and invasion, and promoted apoptosis. The miR-3691-3p target genes E2F transcription factor 3 (E2F3) and PR domain containing 1, with ZNF domain (PRDM1) were upregulated in miR-3691-3p-overexpressing PCa cells, and silencing of E2F3 or PRDM1 suppressed PCa cell proliferation, migration, and invasion. Treatment of mice bearing PCa xenografts with a miR-3691-3p agomir inhibited tumor growth and promoted tumor cell apoptosis. Consistent with the negative regulation of E2F3 and PRDM1 by miR-3691-3p, both proteins were overexpressed in clinical PCa specimens compared with noncancerous prostate tissue. Our results indicate that TGF-β1-regulated miR-3691-3p acts as an anti-oncogene in PCa by downregulating E2F3 and PRDM1. These results provide novel insights into the mechanisms by which TGF-β1 contributes to the progression of PCa.

Genkwadaphnin inhibits growth and invasion in hepatocellular carcinoma by blocking DHCR24-mediated cholesterol biosynthesis and lipid rafts formation

BACKGROUND

The liver is the central organ for cholesterol homoeostasis, and its dysfunction might cause liver pathological alterations including hepatocellular carcinomas (HCCs). 3β-hydroxysteroid-Δ24 reductase (DHCR24), a crucial enzyme of cholesterol biosynthetic pathway, is involved in lipid rafts formation. Genkwadaphnin (GD) is a daphnane diterpene isolated from the flower buds of Daphne genkwa Siebold et Zuccarini (Thymelaeaceae).

METHODS

We evaluated in vitro and in vivo effect of GD using HCC cells and BALB/c nude mice. Microarray assays were used to identify the differential genes by GD. DHCR24 expression and activity, cholesterol level, lipid rafts structure and the role of DHCR24 in human HCC specimens were tested by various molecular biology techniques.

RESULTS

High expression of DHCR24 in human HCC specimens was correlated with poor clinical outcome. Interfering DHCR24 altered growth and migration of HCC cells. GD inhibited growth and metastasis of HCC cells both in vivo and in vitro. GD suppressed DHCR24 expression and activity, as well as DHCR24-mediated cholesterol biosynthesis and lipid rafts formation, then further inhibited HCC cell invasion and migration.

CONCLUSIONS

Our data suggest that DHCR24-mediated cholesterol metabolism might be an effective therapeutic strategy in HCC, and natural product GD might be a promising agent for HCC therapy.

Differential epigenetic regulation between the alternative promoters, PRDM1α and PRDM1β, of the tumour suppressor gene PRDM1 in human multiple myeloma cells

Multiple myeloma (MM) is a B-cell neoplasm that is characterized by the accumulation of malignant plasma cells in the bone marrow. The transcription factor PRDM1 is a master regulator of plasma cell development and is considered to be an oncosuppressor in several lymphoid neoplasms. The PRDM1β isoform is an alternative promoter of the PRDM1 gene that may interfere with the normal role of the PRDM1α isoform. To explain the induction of the PRDM1β isoform in MM and to offer potential therapeutic strategies to modulate its expression, we characterized the cis regulatory elements and epigenetic status of its promoter. We observed unexpected patterns of hypermethylation and hypomethylation at the PRDM1α and PRDM1β promoters, respectively, and prominent H3K4me1 and H3K9me2 enrichment at the PRDM1β promoter in non-expressing cell lines compared to PRDM1β-expressing cell lines. After treatment with drugs that inhibit DNA methylation, we were able to modify the activity of the PRDM1β promoter but not that of the PRDM1α promoter. Epigenetic drugs may offer the ability to control the expression of the PRDM1α/PRDM1β promoters as components of novel therapeutic approaches.

Berberine inhibits proliferation and induces G0/G1 phase arrest in colorectal cancer cells by downregulating IGF2BP3

AIMS

Berberine (BBR) is one of isoquinoline alkaloids from Coptidis Rhizoma and possesses extensive pharmacological activities, including anti-colorectal cancer (CRC) activity. However, the detailed mechanisms remain to be determined. The current study aims to investigate the ability and the potential mechanism of BBR against CRC.

MAIN METHODS

By mining recognized CRC datasets and RNA-seq results of cells and tumors treated with BBR for perform bioinformatics analysis to find key targets IGF2BP3. Overexpression and knockdown of IGF2BP3 assays were used to explore the biological role of IGF2BP3 in the process of BBR against CRC.

KEY FINDINGS

Our results showed that BBR inhibits proliferation and induces G0/G1 phase arrest in CRC cells by downregulating IGF2BP3. Specifically, Knockdown of IGF2BP3 could suppress the PI3K/AKT pathway to inhibit cell proliferation and cycle transition. The negative effects of BBR in CRC cells could be rescued by overexpressing IGF2BP3.

SIGNIFICANCE

Our data might provide a theoretical basis for the future use of BBR in colorectal cancer prevention.

Targeting epigenetic regulators for cancer therapy: mechanisms and advances in clinical trials

Epigenetic alternations concern heritable yet reversible changes in histone or DNA modifications that regulate gene activity beyond the underlying sequence. Epigenetic dysregulation is often linked to human disease, notably cancer. With the development of various drugs targeting epigenetic regulators, epigenetic-targeted therapy has been applied in the treatment of hematological malignancies and has exhibited viable therapeutic potential for solid tumors in preclinical and clinical trials. In this review, we summarize the aberrant functions of enzymes in DNA methylation, histone acetylation and histone methylation during tumor progression and highlight the development of inhibitors of or drugs targeted at epigenetic enzymes.

Emerging Roles of C-Myc in Cancer Stem Cell-Related Signaling and Resistance to Cancer Chemotherapy: A Potential Therapeutic Target Against Colorectal Cancer

Myc is a nuclear transcription factor that mainly regulates cell growth, cell cycle, metabolism, and survival. Myc family proteins contain c-Myc, n-Myc, and l-Myc. Among them, c-Myc can become a promising therapeutic target molecule in cancer. Cancer stem cells (CSCs) are known to be responsible for the therapeutic resistance. In the previous study, we demonstrated that c-Myc mediates drug resistance of colorectal CSCs using a patient-derived primary three-dimensional (3D) organoid culture. In this review, we mainly focus on the roles of c-Myc-related signaling in the regulation of CSCs, chemotherapy resistance, and colorectal cancer organoids. Finally, we introduce the various types of c-Myc inhibitors and propose the possibility of c-Myc as a therapeutic target against colorectal cancer.

PRDM1 silences stem cell-related genes and inhibits proliferation of human colon tumor organoids

PRDM1 is a tumor suppressor that plays an important role in B and T cell lymphomas. Our previous studies demonstrated that PRDM1β is a p53-response gene in human colorectal cancer cells. However, the function of PRDM1β in colorectal cancer cells and colon tumor organoids is not clear. Here we show that PRDM1β is a p53-response gene in human colon organoids and that low PRDM1 expression predicts poor survival in colon cancer patients. We engineered PRDM1 knockouts and overexpression clones in RKO cells and characterized the PRDM1-dependent transcript landscapes, revealing that both the α and β transcript isoforms repress MYC-response genes and stem cell-related genes. Finally, we show that forced expression of PRDM1 in human colon cancer organoids prevents the formation and growth of colon tumor organoids in vitro. These results suggest that p53 may exert tumor-suppressive effects in part through a PRDM1-dependent silencing of stem cell genes, depleting the size of the normal intestinal stem cell compartment in response to DNA damage.

Protein kinase D1 regulates subcellular localisation and metastatic function of metastasis-associated protein 1

BACKGROUND

Cancer progression and metastasis is profoundly influenced by protein kinase D1 (PKD1) and metastasis-associated protein 1 (MTA1) in addition to other pathways. However, the nature of regulatory relationship between the PKD1 and MTA1, and its resulting impact on cancer metastasis remains unknown. Here we present evidence to establish that PKD1 is an upstream regulatory kinase of MTA1.

METHODS

Protein and mRNA expression of MTA1 in PKD1-overexpressing cells were determined using western blotting and reverse-transcription quantitative real-time PCR. Immunoprecipitation and proximity ligation assay (PLA) were used to determine the interaction between PKD1 and MTA1. PKD1-mediated nucleo-cytoplasmic export and polyubiquitin-dependent proteosomal degradation was determined using immunostaining. The correlation between PKD1 and MTA1 was determined using intra-tibial, subcutaneous xenograft, PTEN-knockout (PTEN-KO) and transgenic adenocarcinoma of mouse prostate (TRAMP) mouse models, as well as human cancer tissues.

RESULTS

We found that MTA1 is a PKD1-interacting substrate, and that PKD1 phosphorylates MTA1, supports its nucleus-to-cytoplasmic redistribution and utilises its N-terminal and kinase domains to effectively inhibit the levels of MTA1 via polyubiquitin-dependent proteosomal degradation. PKD1-mediated downregulation of MTA1 was accompanied by a significant suppression of prostate cancer progression and metastasis in physiologically relevant spontaneous tumour models. Accordingly, progression of human prostate tumours to increased invasiveness was also accompanied by decreased and increased levels of PKD1 and MTA1, respectively.

CONCLUSIONS

Overall, this study, for the first time, establishes that PKD1 is an upstream regulatory kinase of MTA1 status and its associated metastatic activity, and that the PKD1-MTA1 axis could be targeted for anti-cancer strategies.

Comparative pan-cancer DNA methylation analysis reveals cancer common and specific patterns

Abnormal DNA methylation is an important epigenetic regulator involving tumorigenesis. Deciphering cancer common and specific DNA methylation patterns is essential for us to understand the mechanisms of tumor development. The Cancer Genome Atlas (TCGA) project provides a large number of samples of different cancers that enable a pan-cancer study of DNA methylation possible. Here we investigate cancer common and specific DNA methylation patterns among 5480 DNA methylation profiles of 15 cancer types from TCGA. We first define differentially methylated CpG sites (DMCs) in each cancer and then identify 5450 hyper- and 4433 hypomethylated pan-cancer DMCs (PDMCs). Intriguingly, three adjacent hypermethylated PDMC constitute an enhancer region, which potentially regulates two tumor suppressor genes BVES and PRDM1 negatively. Moreover, we identify six distinct motif clusters, which are enriched in hyper- or hypomethylated PDMCs and are associated with several well-known cancer hallmarks. We also observe that PDMCs relate to distinct transcriptional groups. Additionally, 55 hypermethylated and 7 hypomethylated PDMCs are significantly associated with patient survival. Lastly, we find that cancer-specific DMCs are enriched in known cancer genes and cell-type-specific super-enhancers. In summary, this study provides a comprehensive investigation and reveals meaningful cancer common and specific DNA methylation patterns.

Prognostic cancer gene signatures share common regulatory motifs

Scientists have discovered various prognostic gene signatures (GSs) in different cancer types. Surprisingly, although different GSs from the same cancer type can be used to measure similar biological characteristics, often rarely is there a gene shared by different GSs. To explain such a paradox, we hypothesized that GSs from the same cancer type may be regulated by common regulatory motifs. To test this hypothesis, we carried out a comprehensive motif analysis on the prognostic GSs from five cancer types. We demonstrated that GSs from individual cancer type as well as across cancer types share regulatory motifs. We also observed that transcription factors that likely bind to these shared motifs have prognostic functions in cancers. Moreover, 75% of the predicted cofactors of these transcription factors may have cancer-related functions and some cofactors even have prognostic functions. In addition, there exist common microRNAs that regulate different GSs from individual cancer types and across cancer types, several of which are prognostic biomarkers for the corresponding cancer types. Our study suggested the existence of common regulatory mechanisms shared by GSs from individual cancer types and across cancer types, which shed light on the discovery of new prognostic GSs in cancers and the understanding of the regulatory mechanisms of cancers.