Transforming Growth Factor and the Role of Epigenetic Aberrancies in Oncogenic Amplifications: A New Perspective in Preventive and Therapeutic Arena

Three genetic mechanisms activate oncogenes in human neoplasms: 1) mutations, 2) gene amplification, and 3) chromosome rearrangements. These mechanisms result in either an alteration of protooncogene structure or an increase in protooncogene expression. The role of epigenetic aberrancies in carcinogenesis has been described earlier however to clinicians, the biological implications of epigenetic therapies to prevent cancer and the mechanisms involved have been a mystery. Furthermore, there is no biomarker suggested to track the carcinogenesis steps long before cancer develops, and this has caused a significant lack of proactive and preventive measures to be taken as all recommendations in preventive oncology are either deficiently and blindly made or through screening methods which are too late in the game. Here we explored a very different approach by applying our deepest understanding of epigenetics and carcinogenesis and even further we developed a framework where our clinical findings could translate to the research and vice versa by generating advanced and novel hypotheses on “how we get cancer”, by exploring the relation between the host and the tumor cells in a way no one had perceived before. The role of specific cancer stem cell pathways is dissected and how to inhibit each of these initiators using multitargeted epigenetic therapies and off-label medications are explained. We should admit that without considering this sophisticated amazing biological network, cancer will remain an unsolved challenge. Further, we were able to solve this unsolved puzzle by bridging the gap from a hypothetical point of view/hypothesis to possibilities that explain the clinical findings we had observed, and conclude that such an approach can completely change the way practitioners are treating cancer.

Epigenetic dysregulation in Epstein-Barr virus-associated gastric carcinoma: Disease and treatments

Epstein-Barr virus(EBV)-associated gastric carcinoma(EBVaGC)comprises nearly 10%of gastric carcinoma cases worldwide.Recently,it was recognised to have unique clinicopathologic characteristics,including male predominance,lower rates of lymph node involvement,and better prognosis.EBVaGC is further characterised by abnormal hypermethylation of tumour suppressor gene promoter regions,causing down-regulation of their expression.In the present review,we critically discuss the role of EBV in gastric carcinogenesis,summarising the role of viral proteins and microRNAs with respect to aberrant methylation in EBVaGC.Given the role of epigenetic dysregulation in tumourigenesis,epigenetic modifiers may represent a novel therapeutic strategy.

Correlation of an ex Vivo Model with Clinical Application of an Epigenetic Modifier, Inhibiting Tumor Growth and Metastasis, in Resistant Cholangiocarcinoma—A Case Study

Bile duct cancer is a rare form of cancer, with approximately 2000 new cases diagnosed in the United States each year. The prognosis of this disease is very grave, especially in the form of intrahepatic (IHCC), as there is no person with stage four who lives for 5 years, and the average prognosis is less than a year, a majority of patients die in less than 6 months despite all therapies. It is suggested that one of the key elements in the disease progression is the intratumoral hypoxia inducible factor one alfa (HIF-1a) as a regulator of malignant behavior and recently described as a new prognostic indicator of IHCC. (9, 10) HIF is a key regulator under the microenvironmental (terrain) influence, and therefore studies of the cell lines in an in vitro environment where there is no hypoxia, usually fail to translate to a clinical outcome in vivo, unless the cells are transfected by full-length HIF-1alpha (fL HIF-1alpha) and dominant-negative HIF-1alpha (dn HIF-1alpha). To overcome this barrier, an ex vivo model is designed at MD Anderson experimental therapeutics where the patient tumor sample is transferred to the mice and treated with drugs, where the tumor can cross talk with the actual terrain and mimic the human stroma where the HIF can be triggered. Results show significant tumor necrosis on the intrahepatic cholangiocacinoma, only after 5 days of exposure to an experimental compound that is known to suppress hypoxia-induced accumulation of hypoxia-inducible factor-1α (HIF-1α) through inhibiting protein synthesis. (11, 12) Further this is explored in the same actual patient with terminal diagnosis, and proves itself with promising initial response. Here, we review this method and the clinical perspectives, and suggest this method to be studied in larger trials.

HiTIP-seq profiles epigenomic reprogramming of patient-derived diffuse midline glioma stem cells to epigenetic therapy

Diffuse midline glioma(DMG),H3K27-altered,is lethal pediatric-type,high-grade,localized to the midline region of the central nervous system.Effective treatment guidelines are absent,and clinical trials are preferred for primary or recur-rent DMG patients.Recently,epigenetic agent-based immunotherapy has exhibited promising therapeutic effects in the clinical setting.However,the underlying mechanisms remain a mystery.The rare DMG tumor samples from biopsy or resection largely impede basic research,by using patient-derived tumor cells which better recapitulate the parental tu-mor’s heterogeneity compared to established cell lines.As an epigenetic reprogramming disease,DMG exhibits a global loss of H3K27 trimethylation(H3K27me3)and a gain of H3K27 acetylation(H3K27ac).Analysis of multiple epige-netic marks is fundamentally necessary.However,traditional techniques cannot allow ultra-low input and high-throughput.Herein we have developed a new method called high-throughput in situ tagged immunoprecipitation sequencing(HiTIP-seq),which uses an integrated superhydrophobic microwell array technology(InSMART).We were able to perform 100 parallel assays from as few as 100 cells per microwell on a single chip.We applied the tech-nology to profile epigenetic alterations of three-dimensional(3D)cell cultures derived from DMG patients.Our HiTIP-seq integrated with RNA sequencing(RNA-seq)analysis revealed that the combination of epigenetic agents(panobino-stat and tazemetostat),reprogrammed histone modifications and drove transcriptome changes.Among them,Wnt inhibitory factor 1(WIF1)has a gain of H3K27ac and a loss of H3K27me3,which leads to the upregulated expression.Altogether,HiTIP-seq is a versatile method for high-throughput analysis of histone modifications,suitable for both DMG research and studying rare 3D models.

Remodeling “cold” tumor immune microenvironment via epigenetic-based therapy using targeted liposomes with in situ formed albumin corona

There is a close connection between epigenetic regulation,cancer metabolism,and immunology.The combination of epigenetic therapy and immunotherapy provides a promising avenue for cancer management.As an epigenetic regulator of histone acetylation,panobinostat can induce histone acetylation and inhibit tumor cell proliferation,as well as regulate aerobic glycolysis and reprogram intratumoral immune cells.JQ1 is a BRD4 inhibitor that can suppress PD-L1 expression.Herein,we proposed a chemo-free,epigenetic-based combination therapy of panobinostat/JQ1 for metastatic colorectal cancer.A novel targeted binary-drug liposome was developed based on lactoferrin-mediated binding with the LRP-1 receptor.It was found that the tumor-targeted delivery was further enhanced by in situ formation of albumin corona.The lactoferrin modification and endogenous albumin adsorption contribute a dual-targeting effect on the receptors of both LRP-1 and SPARC that were overexpressed in tumor cells and immune cells(e.g.,tumor-associated macrophages).The targeted liposomal therapy was effective to suppress the crosstalk between tumor metabolism and immune evasion via glycolysis inhibition and immune normalization.Consequently,lactic acid production was reduced and angiogenesis inhibited;TAM switched to an anti-tumor phenotype,and the anti-tumor function of the effector CD8+T cells was reinforced.The strategy provides a potential method for remodeling the tumor immune microenvironment(TIME).

Epigenetics of human melanoma： promises and challenges

Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the importance of prevention and early detection as well as the need to improve treatment and prognostication of human melanoma. Elucidating the underlying mechanisms of the initi- ation and progression of human melanoma can help identify potential targets of intervention for prevention, diagnosis, therapy, and prognosis of this disease. Aberrant DNA methylation and histone modifications are the best-established epigenetic mechanisms of carcinogenesis. The occurrence of epigenetic changes prior to clinical diagnosis of cancer and their reversibility through pharmaco-logic/genetic approaches offer a promising avenue for basic and translational research on human melanoma. Candidate gene（s） or genome-wide aberrant DNA methylation and histone modifications have been observed in human melanoma tumor tissues and cell lines, and correlated to cellular and functional characteristics and/or clinicopathologicai features of this malignancy. The present review summarizes the published researches on aberrant DNA methylation and histone modifications in connection with human melanoma. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in these epigenetic fields of research. Examples of epigenetic therapy applied for human melanoma in vitro, and the challenges of its in vivo application for clinical treatment of solid tumors are discussed.

Antagonism between gene therapy and epigenetic therapy on human laryngeal carcinoma tumor-bearing mice

Background Gene therapy and epigenetic therapy have gained more attention in cancer treatment. However, the effect of a combined treatment of gene therapy and epigenetic therapy on head and neck squamous cell carcinoma have not been studied yet. To study the mechanism and clinical application, human laryngeal carcinoma cell （Hep-2） tumor-bearing mice were used. Methods A xenograft tumor model was established by the subcutaneous inoculation of Hep-2 cells in the right armpit of BALB/c nu/nu mice. The mice with well-formed tumor were randomly divided into six groups. Multisite injections of rAd-p53 and/or 5-aza-dC were used to treat tumor. Tumor growth was monitored by measuring tumor volume and growth rate. p53 and E-cadherin protein levels in tumor tissues were detected by immunohistochemical staining. The mRNA levels were monitored with FQ-PCR. Results Gene therapy was much more effective than single epigenetic therapy and combined therapy. The gene therapy group has the lowest tumor growth rate and the highest expression levels of p53 and E-cadherin. Conclusions The combined treatment of gene and epigenetic therapy is not suggested for treating head and neck carcinoma, because gene therapy shows an antagonistic effect to epigenetic therapy. However, the mechanisms of action are still unclear.

Potential therapeutic effect of epigenetic therapy on Ireatment-induced neuroendocrine prostate cancer

Although adenocarcinomas of the prostate are relatively indolent, some patients with advanced adenocarcinomas show recurrence of treatment-induced neuroendocrine prostate cancer, which is highly aggressive and lethal. Detailed biological features of treatment-induced neuroendocrine prostate cancer have not been characterized owing to limited biopsies/resections and the lack of a cellular model. In this study, we used a unique cellular model （LNCaP/NE1.8） to investigate the potential role of cancer stem cells in treatment-induced neuroendocrine prostate cancer with acquired resistance to hormonal therapy and chemotherapy. We also studied the role of cancer stem cells in enhancing invasion in treatment-induced neuroendocrine prostate cancer cells that recurred after long-term androgen-ablation treatment. Using an in vitro system mimicking clinical androgen-ablation, our results showed that the neuroendocrine-like subclone NE1.8 cells were enriched with cancer stem cells. Compared to parental prostate adenocarcinoma LNCaP cells, NE1.8 cells are more resistant to androgen deprivation therapy and chemotherapeutic agents and show increased cancer cell invasiveness. Results from this study also suggest a potential epigenetic therapeutic strategy using suberoylanilide hydroxamic acid, a histone deacetylase inhibitor, as a chemotherapeutic agent for therapy-resistant treatment-induced neuroendocrine prostate cancer cells to minimize the risk of prostate cancer recurrence and metastasis.

Potential Mechanisms Underlying the Therapeutic Effects of Electroconvulsive Therapy

In spite of the extensive application of electroconvulsive therapy（ECT）, how it works remains unclear.So far, researchers have made great efforts in figuring out the mechanisms underlying the effect of ECT treatment via determining the levels of neurotransmitters and cytokines and using genetic and epigenetic tools, as well as structural and functional neuroimaging. To help address this question and provide implications for future research, relevant clinical trials and animal experiments are reviewed.