Overexpression of OCT4 induced by modulation of histone marks plays crucial role in breast cancer progression

All eyes on Eya: A unique transcriptional co-activator and phosphatase in cancer

The Eya family of proteins (consisting of Eyas1-4 in mammals) play vital roles in embryogenesis by regulating processes such as proliferation, migration/invasion, cellular survival and pluripotency/plasticity of epithelial and mesenchymal states. Eya proteins carry out such diverse functions through a unique combination of transcriptional co-factor, Tyr phosphatase, and PP2A/B55α-mediated Ser/Thr phosphatase activities. Since their initial discovery, re-expression of Eyas has been observed in numerous tumor types, where they are known to promote tumor progression through a combination of their transcriptional and enzymatic activities. Eya proteins thus reinstate developmental processes during malignancy and represent a compelling class of therapeutic targets for inhibiting tumor progression.

Involvement of CCCTC-binding factor in epigenetic regulation of cancer

A major global health burden continues to be borne by the complex and multifaceted disease of cancer. Epigenetic changes, which are essential for the emergence and spread of cancer, have drawn a huge amount of attention recently. The CCCTC-binding factor (CTCF), which takes part in a wide range of cellular processes including genomic imprinting, X chromosome inactivation, 3D chromatin architecture, local modifications of histone, and RNA polymerase II-mediated gene transcription, stands out among the diverse array of epigenetic regulators. CTCF not only functions as an architectural protein but also modulates DNA methylation and histone modifications. Epigenetic regulation of cancer has already been the focus of plenty of studies. Understanding the role of CTCF in the cancer epigenetic landscape may lead to the development of novel targeted therapeutic strategies for cancer. CTCF has already earned its status as a tumor suppressor gene by acting like a homeostatic regulator of genome integrity and function. Moreover, CTCF has a direct effect on many important transcriptional regulators that control the cell cycle, apoptosis, senescence, and differentiation. As we learn more about CTCF-mediated epigenetic modifications and transcriptional regulations, the possibility of utilizing CTCF as a diagnostic marker and therapeutic target for cancer will also increase. Thus, the current review intends to promote personalized and precision-based therapeutics for cancer patients by shedding light on the complex interplay between CTCF and epigenetic processes.

Overexpression of SOX2 Gene by Histone Modifications: SOX2 Enhances Human Prostate and Breast Cancer Progression by Prevention of Apoptosis and Enhancing Cell Proliferation

INTRODUCTION

SOX2 plays a crucial role in tumor development, cancer stem cell maintenance, and cancer progression. Mechanisms of SOX2 gene regulation in human breast and prostate cancers are not established yet.

METHODS

SOX2 expression in prostate and breast cancer tissues and cell lines was determined by qRT-PCR, Western blot, and immunochemistry, followed by the investigation of pro-tumorigenic properties like cell proliferation, migration, and apoptosis by gene knockdown and treatment with epigenetic modulators and ChIP.

RESULTS

Prostate and breast cancer tissues showed very high expression of SOX2. All cancer cell lines DU145 and PC3 (prostate) and MCF7 and MDA-MB-231 (breast) exhibited high expression of SOX2. Inhibition of SOX2 drastically decreased cell proliferation and migration. Epigenetic modulators enhanced SOX2 gene expression in both cancer types. DNA methylation pattern in SOX2 promoter could not be appreciably counted for SOX2 overexpression. Activation of SOX2 gene promoter was due to very high deposition of H3K4me3 and H3K9acS10p and drastic decrease of H3K9me3 and H3K27me3.

CONCLUSION

Histone modification is crucial for the overexpression of SOX2 during tumor development and cancer progression. These findings show the avenue of co-targeting SOX2 and its active epigenetic modifier enzymes to effectively treat aggressive prostate and breast cancers.

Implications of cancer stem cells in diabetes and pancreatic cancer

This review provides a detailed study of pancreatic cancer (PC) and the implication of different types of cancers concerning diabetes. The combination of anti-diabetic drugs with other anti-cancer drugs and phytochemicals can help prevent and treat this disease. PC cancer stem cells (CSCs) and how they migrate and develop into malignant tumors are discussed. A detailed explanation of the different mechanisms of diabetes development, which can enhance the pancreatic CSCs' proliferation by increasing the IGF factor levels, epigenetic modifications, DNA damage, and the influence of lifestyle factors like obesity, and inflammation, has been discussed. It also explains how cancer due to diabetes is associated with high mortality rates. One of the well-known diabetic drugs, metformin, can be combined with other anti-cancer drugs and prevent the development of PC and has been taken as one of the prime focus in this review. Overall, this paper provides insight into the relationship between diabetes and PC and the methods that can be employed to diagnose this disease at an earlier stage successfully.

Epigenetic Factors as Etiological Agents, Diagnostic Markers, and Therapeutic Targets for Luminal Breast Cancer

Luminal breast cancer, an etiologically heterogeneous disease, is characterized by high steroid hormone receptor activity and aberrant gene expression profiles. Endocrine therapy and chemotherapy are promising therapeutic approaches to mitigate breast cancer proliferation and recurrence. However, the treatment of therapy-resistant breast cancer is a major challenge. Recent studies on breast cancer etiology have revealed the critical roles of epigenetic factors in luminal breast cancer tumorigenesis and drug resistance. Tumorigenic epigenetic factor-induced aberrant chromatin dynamics dysregulate the onset of gene expression and consequently promote tumorigenesis and metastasis. Epigenetic dysregulation, a type of somatic mutation, is a high-risk factor for breast cancer progression and therapy resistance. Therefore, epigenetic modulators alone or in combination with other therapies are potential therapeutic agents for breast cancer. Several clinical trials have analyzed the therapeutic efficacy of potential epi-drugs for breast cancer and reported beneficial clinical outcomes, including inhibition of tumor cell adhesion and invasiveness and mitigation of endocrine therapy resistance. This review focuses on recent findings on the mechanisms of epigenetic factors in the progression of luminal breast cancer. Additionally, recent findings on the potential of epigenetic factors as diagnostic biomarkers and therapeutic targets for breast cancer are discussed.

Comprehensive Analysis of YTHDF1 Immune Infiltrates and ceRNA in Human Esophageal Carcinoma

Background: YTHDF1 is highly expressed in multiple tumors and affects tumor progression. However, there are only a few comprehensive studies on the analysis of YTHDF1 in esophageal cancer.

Methods: We analyzed YTHDF1 expression in pan-cancer by comparing both the GEPIA and TCGA cohorts, and further verified the differences in YTHDF1 expression between the ESCA and normal groups by the GEO ESCA cohort and in vitro experiments. The correlation of YTHDF1 expression and the clinical characteristics of ESCA patients was analyzed using the TCGA ESCA clinical data. The GO and KEGG enrichment analyses of the YTHDF1 coexpressed genes were completed by bioinformatics analysis, and the GGI and PPI were constructed for the YTHDF1, respectively. The relationship between YTHDF1 expression and the infiltration of ESCA immune cells was analyzed by using the TIMER database and the TCGA ESCA cohort. The relationships between YTHDF1 expression levels and glycolysis and ferroptosis-related genes were analyzed using the TCGA and GEPIA ESCA cohorts. Finally, the ceRNA network that may be involved in YTHDF1 in ESCA was predicted and constructed through a variety of databases.

Results: YTHDF1 was overexpressed in various cancers, and in vitro experiments confirmed that YTHDF1 expression was higher in ESCA samples than in normal samples. The expression of YTHDF1 has some accuracy in predicting the tumor outcome. Expression of YTHDF1 was significantly associated with multiple clinical features in ESCA patients. GO and KEGG enrichment analyses indicated that YTHDF1 coexpressed genes involved multiple biological functions. There is a potential association between YTHDF1 expression and multiple immune cell infiltration, glycolysis, and ferroptosis-related genes in ESCA. YTHDF1 may be involved in multiple ceRNA regulatory networks in ESCA, including PAXIP1-AS1/hsa-miR-376c-3p/YTHDF1 axis, THUMPD3-AS1/hsa-miR-655-3p/YTHDF1 axis, and SNHG20/hsa-miR-655-3p/YTHDF1 axis, respectively.

Conclusion: YTHDF1 can serve as a biomarker of ESCA, related to the immune cell infiltration of ESCA, regulation of glycolysis and ferroptosis, and the ceRNA regulatory network.

Synthetic and immunological studies on the OCT4 immunodominant motif antigen-based anti-cancer vaccine

Objective: Cancer stem cell is one of the important causes of tumorigenesis as well as a drug target in the treatment of malignant tumor. However, at present, there is no immune vaccine targeting these cells. Octamer-binding transcription factor 4 (OCT4), a marker of embryonic stem cells and germ cells, often highly expresses in the early stages of tumorigenesis and is therefore a good candidate for cancer vaccine development.

Methods: To identify the optimal carrier and adjuvant combination, we chemically synthesized and linked three different OCT4 epitope antigens to a carrier protein, keyhole limpet hemocyanin (KLH), combined with Toll-like receptor 9 agonist (TLR9).

Results: Immunization with OCT4-3 + TLR9 produced the strongest immune response in mice. In prevention assays, significant tumor growth inhibition was achieved in BABL/c mice treated with OCT4-3 + TLR9 (P < 0.01). Importantly, the results showed that cytotoxic T lymphocyte activity and the inhibition of tumor growth were enhanced in mice immunized with OCT4-3 combined with TLR9. Meanwhile, multiple cytokines [such as interferon (IFN)-γ (P < 0.05), interleukin (IL)-12 (P < 0.05), IL-2 (P < 0.01), and IL-6 (P < 0.05)] promoting cellular immune responses were shown to be greatly enhanced in mice immunized with OCT4-3 + TLR9. Moreover, we considered safety considerations in terms of the composition of the vaccines to help facilitate the development of effective next-generation vaccines.

Conclusions: Collectively, these experiments demonstrated that combination therapy with TLR9 agonist induced a tumor-specific adaptive immune response, leading to the suppression of primary tumor growth in testis embryonic carcinoma.

Emerging histone glutamine modifications mediated gene expression in cell differentiation and the VTA reward pathway

Gene expression is the key to cellular functions and homeostasis. Histone modifications regulate chromatin dynamics and gene expression. Neuronal cell functions largely depend on fluxes of neurotransmitters for activation of chromatin and gene expression. New studies by Lepack et al. and Farrelly et al. recently demonstrated how tissue transglutaminase 2 (TGM2) mediated histone glutamine modifications, either dopaminylation in the dopaminergic reward pathway or serotonylation in the context of cellular differentiation and signaling regulate gene expression and decipher striking differences from their known functions. This opens new avenues of research in the field of epigenetics in general and neuroepigenetics as special; and to find out the enzymes responsible for the reversible reaction of histone de-dopaminylation and de-serotonylation.

Reprogramming and transdifferentiation - two key processes for regenerative medicine

Regenerative medicine based on transplants obtained from donors or foetal and new-born mesenchymal stem cells, encounter important obstacles such as limited availability of organs, ethical issues and immune rejection. The growing demand for therapeutic methods for patients being treated after serious accidents, severe organ dysfunction and an increasing number of cancer surgeries, exceeds the possibilities of the therapies that are currently available. Reprogramming and transdifferentiation provide powerful bioengineering tools. Both procedures are based on the somatic differentiated cells, which are easily and unlimitedly available, like for example: fibroblasts. During the reprogramming procedure mature cells are converted into pluripotent cells - which are capable to differentiate into almost any kind of desired cells. Transdifferentiation directly converts differentiated cells of one type into another differentiated cells type. Both procedures allow to obtained patient's dedicated cells for therapeutic purpose in regenerative medicine. In combination with biomaterials, it is possible to obtain even whole anatomical structures. Those patient's dedicated structures may serve for them upon serious accidents with massive tissue damage but also upon cancer surgeries as a replacement of damaged organ. Detailed information about reprogramming and transdifferentiation procedures as well as the current state of the art are presented in our review.

Roles of OCT4 in pathways of embryonic development and cancer progression

Somatic cells may be reprogrammed to pluripotent state by ectopic expression of certain transcription factors; namely, OCT4, SOX2, KLF4 and c-MYC. However, the molecular and cellular mechanisms are not adequately understood, especially for human embryonic development. Studies during the last five years implicated importance of OCT4 in human zygotic genome activation (ZGA), patterns of OCT4 protein folding and role of specialized sequences in binding to DNA for modulation of gene expression during development. Epigenetic modulation of OCT4 gene and post translational modifications of OCT4 protein activity in the context of multiple cancers are important issues. A consensus is emerging that chromatin organization and epigenetic landscape play crucial roles for the interactions of transcription factors, including OCT4 with the promoters and/or regulatory sequences of genes associated with human embryonic development (ZGA through lineage specification) and that when the epigenome niche is deregulated OCT4 helps in cancer progression, and how OCT4 silencing in somatic cells of adult organisms may impact ageing.

Cancer-associated missense mutations enhance the pluripotency reprogramming activity of OCT4 and SOX17

The functional consequences of cancer-associated missense mutations are unclear for the majority of proteins. We have previously demonstrated that the activity of SOX and Pit-Oct-Unc (POU) family factors during pluripotency reprogramming can be switched and enhanced with rationally placed point mutations. Here, we interrogated cancer mutation databases and identified recurrently mutated positions at critical structural interfaces of the DNA-binding domains of paralogous SOX and POU family transcription factors. Using the conversion of mouse embryonic fibroblasts to induced pluripotent stem cells as functional readout, we identified several gain-of-function mutations that enhance pluripotency reprogramming by SOX2 and OCT4. Wild-type SOX17 cannot support reprogramming but the recurrent missense mutation SOX17-V118M is capable of inducing pluripotency. Furthermore, SOX17-V118M promotes oncogenic transformation, enhances thermostability and elevates cellular protein levels of SOX17. We conclude that the mutational profile of SOX and POU family factors in cancer can guide the design of high-performance reprogramming factors. Furthermore, we propose cellular reprogramming as a suitable assay to study the functional impact of cancer-associated mutations.

H3K9me3, H3K36me3, and H4K20me3 Expression Correlates with Patient Outcome in Esophageal Squamous Cell Carcinoma as Epigenetic Markers

BACKGROUND

Histone methylation, as an essential pattern of posttranslational modifications, contributes to multiple cancer-related biological processes. Dysregulation of histone methylation is now considered a biomarker for cancer prognosis.

AIMS

This study investigated and evaluated the potential role of four histone lysine trimethylation markers as biomarkers for esophageal squamous cell carcinoma (ESCC) prognosis.

METHODS

Tissue arrays were made from 135 paraffin-embedded ESCC samples and examined for histone markers by immunohistochemistry, and 10 pairs of cancer and noncancerous mucosa tissues from ESCC patients were investigated with Western blot. Chi-squared test, Kaplan-Meier analysis with log-rank test, and Cox proportional hazard trend analyses were performed to assess the prognostic values of the markers.

RESULTS

Histone 3 lysine 4 trimethylation (H3K4me3), histone 3 lysine 9 trimethylation (H3K9me3), and histone 4 lysine 20 trimethylation (H4K20me3), but not histone 3 lysine 36 trimethylation (H3K36me3), showed stronger immunostaining signals in tumor tissues than in the corresponding adjacent non-neoplastic mucosa tissues. The expression patterns of H3K36me3, H3K9me3, and H4K20me3 correlated with tumor infiltrating depth, lymph node involvement, and pTNM stage. Low-scoring H3K9me3 and H4K20me3 predicted better prognosis, while H3K36me3 manifested the opposite trend. Poor prognosis occurred in ESCC patients with expression patterns of high levels of H3K9me3, high levels of H4K20me3, and low levels of H3K36me3 expression.

CONCLUSIONS

H3K9me3, H4K20me3, and H3K36me3 showed a close relationship with clinical features and were considered independent risk factors for survival of ESCC patients. The combination of H3K9me3, H4K20me3, and H3K36me3 expression, rather than the expression of a single histone marker, is believed to further enhance evaluations of ESCC prognosis and management.

The RND1 Small GTPase: Main Functions and Emerging Role in Oncogenesis

The Rho GTPase family can be classified into classic and atypical members. Classic members cycle between an inactive Guanosine DiPhosphate -bound state and an active Guanosine TriPhosphate-bound state. Atypical Rho GTPases, such as RND1, are predominantly in an active GTP-bound conformation. The role of classic members in oncogenesis has been the subject of numerous studies, while that of atypical members has been less explored. Besides the roles of RND1 in healthy tissues, recent data suggest that RND1 is involved in oncogenesis and response to cancer therapeutics. Here, we present the current knowledge on RND1 expression, subcellular localization, and functions in healthy tissues. Then, we review data showing that RND1 expression is dysregulated in tumors, the molecular mechanisms involved in this deregulation, and the role of RND1 in oncogenesis. For several aggressive tumors, RND1 presents the features of a tumor suppressor gene. In these tumors, low expression of RND1 is associated with a bad prognosis for the patients. Finally, we highlight that RND1 expression is induced by anticancer agents and modulates their response. Of note, RND1 mRNA levels in tumors could be used as a predictive marker of both patient prognosis and response to anticancer agents.

Female Sex Hormones Activate Human Endogenous Retrovirus Type K Through the OCT4 Transcription Factor in T47D Breast Cancer Cells

Female sex hormones, the octamer-binding transcription factor 4 (OCT4), and human endogenous retroviruses (HERVs) are all involved in the development of breast cancer. However, whether there are cross talks between these factors to promote breast cancer is still unknown. Using the T47D human breast cancer cell line, we have found that estradiol and progesterone synergistically activate HERV-K through nuclear receptors. The progesterone receptor (isoform B) binds a progesterone-response element (PRE) in a long terminal repeat (LTR5HS) of HERV-K. There is another transcription factor-binding element in the LTR, the octamer motif, which is required for the hormones to activate gene transcription downstream of the LTR. Gel shift assays and co-immunoprecipitation indicate that the progesterone receptor (PR) and the OCT4 transcription factor interact on the protein level. Methylation of the PRE enhances binding of the PR. These findings help to elucidate the previously unknown cross talks among the sex hormones, OCT4, and HERVs in contributing to breast cancer proliferation and tumorigenesis, which may be useful in guiding further development of cancer therapies.