Epigenetic Drug Therapy in the Treatment of Colorectal Cancer

Breviscapine regulates the proliferation, migration, invasion, and apoptosis of colorectal cancer cells via the PI3K/AKT pathway

Colorectal cancer (CRC) is ranked as one of the most common malignancies with a high death rate. It has been discovered that breviscapine can alter the progression and development of various cancers. Nevertheless, the function and mechanisms of breviscapine in CRC progression have not yet been described. The cell proliferation capacity of HCT116 and SW480 cells was assessed using the CCK-8 and EdU assays. Cell apoptosis was tested through flow cytometry, and cell migration and invasion were examined using the transwell assay. Moreover, protein expression was examined through a western blot. Tumor weight and volume were assessed using the nude mice in vivo assay, and the Ki-67 protein expression was verified through the IHC assay. This study discovered that an increased dose of breviscapine (0, 12.5, 25, 50, 100, 200, and 400 μM) gradually reduced cell proliferation and increased apoptosis in CRC. Additionally, breviscapine restricted the migration and invasion CRC cells. Moreover, it was revealed that breviscapine inactivated the PI3K/AKT pathway and inhibited CRC progression. Finally, an in vivo assay demonstrated that breviscapine restrained tumor growth in vivo. It affected the CRC cells' proliferation, migration, invasion, and apoptosis through the PI3K/AKT pathway. This discovery may offer new insights into CRC treatment.

Intestinal organoids: A versatile platform for modeling gastrointestinal diseases and monitoring epigenetic alterations

Considering the significant limitations of conventional 2D cell cultures and tissue in vitro models, creating intestinal organoids has burgeoned as an ideal option to recapitulate the heterogeneity of the native intestinal epithelium. Intestinal organoids can be developed from either tissue-resident adult stem cells (ADSs) or pluripotent stem cells (PSCs) in both forms induced PSCs and embryonic stem cells. Here, we review current advances in the development of intestinal organoids that have led to a better recapitulation of the complexity, physiology, morphology, function, and microenvironment of the intestine. We discuss current applications of intestinal organoids with an emphasis on disease modeling. In particular, we point out recent studies on SARS-CoV-2 infection in human intestinal organoids. We also discuss the less explored application of intestinal organoids in epigenetics by highlighting the role of epigenetic modifications in intestinal development, homeostasis, and diseases, and subsequently the power of organoids in mirroring the regulatory role of epigenetic mechanisms in these conditions and introducing novel predictive/diagnostic biomarkers. Finally, we propose 3D organoid models to evaluate the effects of novel epigenetic drugs (epi-drugs) on the treatment of GI diseases where epigenetic mechanisms play a key role in disease development and progression, particularly in colorectal cancer treatment and epigenetically acquired drug resistance.

Preclinical and clinical aspects of using Tazemetostate in human cancers

Abstract:

Epigenetic drugs are novel drug categories with promising effects in different cancers. Tazemetostate is among the drugs that were recently used in clinical settings, especially in the treatment of specific tumors and lymphomas. There are a growing number of ongoing clinical trials evaluating the safety and efficacy of tazemetostate in different cancers. The present review addressed the available preclinical studies evaluating the combination of tazemetostate and other chemotherapy agents in treating different cancers and summarized the limited clinical evidence available regarding the efficacy of this novel Enhancer of Zeste Homolog 2 (EZH2) inhibitor in cancer. Based on the available clinical studies, tazemetostate could be considered a safe epigenetic agent with limited adverse events for treating specific types of lymphomas and solid tumors. However, the superiority of using tazemetostate over other chemotherapy agents in patients with cancer as well as using the drug for other clinical conditions including non-alcoholic steatohepatitis needs further investigation. Moreover, the effect of tazemetostate on human germline cells is clearly evaluated as some animal studies demonstrated that the drug can affect germline epigenome suggesting further studies on this issue.

Moderate DNA hypomethylation suppresses intestinal tumorigenesis by promoting caspase-3 expression and apoptosis

Global DNA hypomethylation is a most common epigenetic alteration in human neoplasia. However, accumulative evidence shows that global DNA hypomethylation impacts tumorigenesis in a tissue-specific manner, promoting tumorigenesis in some but suppressing tumorigenesis in others including colorectal cancer. The underlying mechanisms, especially how DNA hypomethylation suppresses tumorigenesis, remain largely unknown. Here, we investigate how DNA hypomethylation affects intestinal tumorigenesis by using an Uhrf1 tandem tudor domain knockin mutant mouse model (Uhrf1^ki/ki) that exhibits a moderate ~10% reduction of global DNA methylation. We found that both chemical-induced colorectal carcinogenesis and Apc loss of heterozygosity (LOH)-induced intestinal tumorigenesis are substantially suppressed in the Uhrf1 mutant mice. Furthermore, unlike Dnmt1 hypomorphic mice in which DNA hypomethylation suppresses the incidence of macroscopic intestinal tumors but promotes the formation of microadenoma in Apc^Min/+ background, Uhrf1^ki/ki/Apc^Min/+ mice have markedly reduced incidence of both microadenoma and macroadenoma. DNA hypomethylation does not appear to affect Apc LOH, activation of the Wnt or Hippo pathway, or tumor cell proliferation, but acts cooperatively with activated Wnt pathway to enhance the caspase-3 gene expression, activation, and apoptosis. Furthermore, increased caspase-3 expression correlates with DNA hypomethylation within the caspase-3 enhancer regions. Taken together, we present a new mouse model for investigating the role of and the molecular mechanisms by which DNA hypomethylation suppresses intestinal tumorigenesis. Our finding that a moderate DNA hypomethylation is sufficient to suppress intestinal tumorigenesis by promoting caspase-3 expression and apoptosis sheds new light on DNA-methylation inhibitor-based colorectal cancer therapeutics.

Finding an easy way to harmonize: a review of advances in clinical research and combination strategies of EZH2 inhibitors

Enhancer of zeste homolog 2 inhibitors (EZH2i) have garnered increased attention owing to their anticancer activity by targeting EZH2, a well-known cancer-promoting factor. However, some lymphomas are resistant to EZH2i, and EZH2i treatment alone is ineffective in case of EZH2-overexpressing solid tumors. The anti-cancer efficacy of EZH2i may be improved through safe and effective combinations of these drugs with other treatment modalities. Preclinical evidence indicates that combining EZH2i with other therapies, such as immunotherapy, chemotherapy, targeted therapy, and endocrine therapy, has complementary or synergistic antitumor effects. Therefore, elucidating the underlying mechanisms of the individual constituents of the combination therapies is fundamental for their clinical application. In this review, we have summarized notable clinical trials and preclinical studies using EZH2i, their progress, and combinations of EZH2i with different therapeutic modalities, aiming to provide new insights for tumor treatment.

The Impact of Statin Therapy on the Survival of Patients with Gastrointestinal Cancer

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors that may play an important role in the evolution of cancers, due to their effects on cancer cell metabolism. Statins affect several potential pathways, including cell proliferation, angiogenesis, apoptosis and metastasis. The number of trials assessing the putative clinical benefits of statins in cancer is increasing. Currently, there are several trials listed on the global trial identifier website clinicaltrials.gov. Given the compelling evidence from these trials in a variety of clinical settings, there have been calls for a clinical trial of statins in the adjuvant gastrointestinal cancer setting. However, randomized controlled trials on specific cancer types in relation to statin use, as well as studies on populations without a clinical indication for using statins, have elucidated some potential underlying biological mechanisms, and the investigation of different statins is probably warranted. It would be useful for these trials to incorporate the assessment of tumour biomarkers predictive of statin response in their design. This review summarizes the recent preclinical and clinical studies that assess the application of statins in the treatment of gastrointestinal cancers with particular emphasize on their association with cancer risk.

Association between non-alcoholic fatty liver disease and colorectal cancer

Introduction: Colorectal cancer (CRC) is a common malignancy, ranking fourth among the causes of cancer-related deaths globally. Its incidence has increased in recent decades, and now more than one million CRC patients are diagnosed and thousands die annually. The 5-year survival rate varies with the stage at diagnosis, are approximately 90% in the early stages of disease, and less than 10% in advanced disease. Non-alcoholic fatty liver disease (NAFLD), which is a major cause of chronic liver disease, and characterized by the accumulation of fat in hepatocytes, has also emerged as a risk factor for CRC, and to be related with the development of colorectal polyps. Areas covered: The purpose of this current review is to summarize the main findings of studies that have investigated the role of NAFLD in development of CRC. Expert opinion: Various molecular pathways are altered during the development of NAFLD, which are also important in CRC tumorigenesis. There is growing body of evidence showing the potential role of activation of pro-inflammatory, disruption of anti-inflammatory pathways, increasing the activity of pathways involved in cell proliferation/survival. Thus targeting these dysregulated pathways via novel inhibitors can be a potential therapy for CRC prevention in cases with NAFLD.

Targeting cancer stem cells as therapeutic approach in the treatment of colorectal cancer

Colorectal cancer is one of the most common cancers globally. A large portion of colorectal cancer patients who are treated with conventional chemotherapy eventually develop local recurrence or metastases. The failure of a complete cure in colorectal cancer patients may be related to the lack of complete eradication of cancer stem cells when using conventional therapy. Colorectal cancer stem cells comprise a small population of tumor cells that possess the properties of rapid proliferation and differentiation. The colorectal cancer stem cells are also phenotypically and molecularly distinct, and resistant to conventional chemo-radiotherapy. Therefore, it is important to identify approaches in combination with conventional therapy for targeting and eradicating cancer cells. The aim of this review was to summarize the main findings of recent studies on targeting colorectal cancer stem cells as a novel therapeutic approach in colorectal cancer treatment.