Epithelial-Mesenchymal Transition in Acute Leukemias.

Epithelial-mesenchymal transition (EMT) is a metabolic process that confers phenotypic flexibility to cells and the ability to adapt to new functions. This transition is critical during embryogenesis and is required for the differentiation of many tissues and organs. EMT can also be induced in advanced-stage cancers, leading to further malignant behavior and chemotherapy resistance, resulting in an unfavorable prognosis for patients. Although EMT was long considered and studied only in solid tumors, it has been shown to be involved in the pathogenesis of hematological malignancies, including acute leukemias. Indeed, there is increasing evidence that EMT promotes the progression of acute leukemias, leading to the emergence of a more aggressive phenotype of the disease, and also causes chemotherapy resistance. The current literature suggests that the levels and activities of EMT inducers and markers can be used to predict prognosis, and that targeting EMT in addition to conventional therapies may increase treatment success in acute leukemias.

Critical Roles of SRC-3 in the Development and Progression of Breast Cancer, Rendering It a Prospective Clinical Target.

Breast cancer (BCa) is the most frequently diagnosed malignant tumor in women and is also one of the leading causes of cancer-related death. Most breast tumors are hormone-dependent and estrogen signaling plays a critical role in promoting the survival and malignant behaviors of these cells. Estrogen signaling involves ligand-activated cytoplasmic estrogen receptors that translocate to the nucleus with various co-regulators, such as steroid receptor co-activator (SRC) family members, and bind to the promoters of target genes and regulate their expression. SRC-3 is a member of this family that interacts with, and enhances, the transcriptional activity of the ligand activated estrogen receptor. Although SRC-3 has important roles in normal homeostasis and developmental processes, it has been shown to be amplified and overexpressed in breast cancer and to promote malignancy. The malignancy-promoting potential of SRC-3 is diverse and involves both promoting malignant behavior of tumor cells and creating a tumor microenvironment that has an immunosuppressive phenotype. SRC-3 also inhibits the recruitment of tumor-infiltrating lymphocytes with effector function and promotes stemness. Furthermore, SRC-3 is also involved in the development of resistance to hormone therapy and immunotherapy during breast cancer treatment. The versatility of SRC-3 in promoting breast cancer malignancy in this way makes it a good target, and methodical targeting of SRC-3 probably will be important for the success of breast cancer treatment.

Aldehyde Dehydrogenase Genes as Prospective Actionable Targets in Acute Myeloid Leukemia.

It has been previously shown that the aldehyde dehydrogenase (ALDH) family member ALDH1A1 has a significant association with acute myeloid leukemia (AML) patient risk group classification and that AML cells lacking ALDH1A1 expression can be readily killed via chemotherapy. In the past, however, a redundancy between the activities of subgroup members of the ALDH family has hampered the search for conclusive evidence to address the role of specific ALDH genes. Here, we describe the bioinformatics evaluation of all nineteen member genes of the ALDH family as prospective actionable targets for the development of methods aimed to improve AML treatment. We implicate ALDH1A1 in the development of recurrent AML, and we show that from the nineteen members of the ALDH family, ALDH1A1 and ALDH2 have the strongest association with AML patient risk group classification. Furthermore, we discover that the sum of the expression values for RNA from the genes, ALDH1A1 and ALDH2, has a stronger association with AML patient risk group classification and survival than either one gene alone does. In conclusion, we identify ALDH1A1 and ALDH2 as prospective actionable targets for the treatment of AML in high-risk patients. Substances that inhibit both enzymatic activities constitute potentially effective pharmaceutics.

The Molecular Context of Oxidant Stress Response in Cancer Establishes ALDH1A1 as a Critical Target: What This Means for Acute Myeloid Leukemia.

The protein family of aldehyde dehydrogenases (ALDH) encompasses nineteen members. The ALDH1 subfamily consists of enzymes with similar activity, having the capacity to neutralize lipid peroxidation products and to generate retinoic acid; however, only ALDH1A1 emerges as a significant risk factor in acute myeloid leukemia. Not only is the gene ALDH1A1 on average significantly overexpressed in the poor prognosis group at the RNA level, but its protein product, ALDH1A1 protects acute myeloid leukemia cells from lipid peroxidation byproducts. This capacity to protect cells can be ascribed to the stability of the enzyme under conditions of oxidant stress. The capacity to protect cells is evident both in vitro, as well as in mouse xenografts of those cells, shielding cells effectively from a number of potent antineoplastic agents. However, the role of ALDH1A1 in acute myeloid leukemia has been unclear in the past due to evidence that normal cells often have higher aldehyde dehydrogenase activity than leukemic cells. This being true, ALDH1A1 RNA expression is significantly associated with poor prognosis. It is hence imperative that ALDH1A1 is methodically targeted, particularly for the acute myeloid leukemia patients of the poor prognosis risk group that overexpress ALDH1A1 RNA.

HN1 Is Enriched in the S-Phase, Phosphorylated in Mitosis, and Contributes to Cyclin B1 Degradation in Prostate Cancer Cells.

HN1 has previously been shown as overexpressed in various cancers. In Prostate cancer, it regulates AR signaling and centrosome-related functions. Previously, in two different studies, HN1 expression has been observed as inversely correlated with Cyclin B1. However, HN1 interacting partners and the role of HN1 interactions in cell cycle pathways have not been completely elucidated. Therefore, we used Prostate cancer cell lines again and utilized both transient and stable inducible overexpression systems to delineate the role of HN1 in the cell cycle. HN1 characterization was performed using treatments of kinase inhibitors, western blotting, flow cytometry, immunofluorescence, cellular fractionation, and immunoprecipitation approaches. Our findings suggest that HN1 overexpression before mitosis (post-G2), using both transient and stable expression systems, leads to S-phase accumulation and causes early mitotic exit after post-G2 overexpression. Mechanistically, HN1 interacted with Cyclin B1 and increased its degradation via ubiquitination through stabilized Cdh1, which is a co-factor of the APC/C complex. Stably HN1-expressing cells exhibited a reduced Cdt1 loading onto chromatin, demonstrating an exit from a G1 to S phenotype. We found HN1 and Cdh1 interaction as a new regulator of the Cyclin B1/CDK1 axis in mitotic regulation which can be explored further to dissect the roles of HN1 in the cell cycle.

OGG1 as an Epigenetic Reader Affects NFκB: What This Means for Cancer.

8-oxoguanine glycosylase 1 (OGG1), which was initially identified as the enzyme that catalyzes the first step in the DNA base excision repair pathway, is now also recognized as a modulator of gene expression. What is important for cancer is that OGG1 acts as a modulator of NFκB-driven gene expression. Specifically, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, such as NFκB to their cognate sites, enabling the expression of cytokines and chemokines, with ensuing recruitment of inflammatory cells. Recently, we highlighted chief aspects of OGG1 involvement in regulation of gene expression, which hold significance in lung cancer development. However, OGG1 has also been implicated in the molecular underpinning of acute myeloid leukemia. This review analyzes and discusses how these cells adapt through redox-modulated intricate connections, via interaction of OGG1 with NFκB, which provides malignant cells with alternative molecular pathways to transform their microenvironment, enabling adjustment, promoting cell proliferation, metastasis, and evading killing by therapeutic agents.

Increased ROS alters E-/N-cadherin levels and promotes migration in prostate cancer cells.

BACKGROUND: Increased ROS has been reported to cause a change in E- and N-cadherin levels, and consequently promotes migrative behaviors in pancreas and breast cancer cells. In this study, the effect of a sublethal dose of H2O2 on E- and N-cadherin levels, and on migrative behaviors of PCa cells was investigated. METHODS: To determine a sublethal concentration of H2O2 on cell proliferation and ROS production were examined using WST-1 and DCFH-DA assays, respectively. E- and N-cadherin protein and mRNA levels were investigated by western blotting and real-time PCR, respectively. The migrative potentials of the cells were examined by Cytoselect 96-well cell migration assay. RESULTS: Treatment of the PCa cells with a sublethal dose of H2O2 results in a decrease in E-cadherin and an increase in N-cadherin levels, at both mRNA and protein levels. However, inhibition of ERK using PD98059 abolishes the effects of H2O2. In addition, the cells that were treated with H2O2 have gained further migrative abilities compared to control cells, and this ability was repressed when PD98059 was used together with H2O2. CONCLUSION: Increased ROS alters E- and N-cadherin levels in an ERK-dependent manner and thereby promotes the migrative abilities of PCa cells (Fig. 3, Ref. 32).

Decreased Expression of HN1 Sensitizes Prostate Cancer Cells to Apoptosis Induced by Docetaxel and 2-Methoxyestradiol.

OBJECTIVE: Prostate cancer is one of the most frequently diagnosed cancer in men and ranks as the second most common cause of cancer-related deaths in developed countries. HN1 is a highly expressed gene in prostate cancer and controls the levels of several cell cycle regulatory proteins including Cyclin B1. Cyclin B1 is a cell cycle control protein but is also involved in Docetaxel and 2-Methoxyestradiol induced apoptosis. Since Cyclin B1 level may affect chemotherapy success and HN1-Cyclin B1 negative correlation has already been shown, so in this study, we investigated the possible role of HN1 in chemotherapeutic resistance in prostate cancer cells. METHODS: Androgen-dependent and independent prostate cancer cells were used in the study. A full-length human HN1 cDNA fragment was cloned to a mammalian expression vector and this construct was used for overexpression experiments. A siRNA that specifically targets HN1 was used for HN1 depletion experiments. Evaluation of apoptosis was performed by the level of PARP cleavage and an apoptosis kit that measure Caspase 3 activity. RESULTS: The HN1 protein level is decreased in the Docetaxel or 2-Methoxyestradiol treated LNCaP and PC-3 PCa cells whereas the Cyclin B1 level is increased. HN1 overexpression inhibited Docetaxel and 2-Methoxyestradiol induced apoptosis. In concordance, its depletion further stimulated apoptosis in drug-treated cells. However, silencing of Cyclin B1 along with HN1 abolished the increased apoptotic response induced by silencing of HN1 in Docetaxel or 2-Methoxyestradiol treated cells. CONCLUSION: HN1 is an anti-apoptotic molecule and inhibits Docetaxel and 2-Methoxyestradiol induced apoptosis by targeting Cyclin B1.

Dissecting the effects of androgen deprivation therapy on cadherin switching in advanced prostate cancer: A molecular perspective.

Prostate cancer is one of the most often diagnosed malignancies in males and its prevalence is rising in both developed and developing countries. Androgen deprivation therapy has been used as a standard treatment approach for advanced prostate cancer for more than 80 years. The primary aim of androgen deprivation therapy is to decrease circulatory androgen and block androgen signaling. Although a partly remediation is accomplished at the beginning of treatment, some cell populations become refractory to androgen deprivation therapy and continue to metastasize. Recent evidences suggest that androgen deprivation therapy may cause cadherin switching, from E-cadherin to N-cadherin, which is the hallmark of epithelial-mesenchymal transition. Diverse direct and indirect mechanisms are involved in this switching and consequently, the cadherin pool changes from E-cadherin to N-cadherin in the epithelial cells. Since E-cadherin represses invasive and migrative behaviors of the tumor cells, the loss of E-cadherin disrupts epithelial tissue structure leading to the release of tumor cells into surrounding tissues and circulation. In this study, we review the androgen deprivation therapy-dependent cadherin switching in advanced prostate cancer with emphasis on its molecular basis especially the transcriptional factors regulated through TFG-ß pathway.

HN1 interacts with γ-tubulin to regulate centrosomes in advanced prostate cancer cells.

Prostate cancer is one of the most common cancer for men worldwide with advanced forms showing supernumerary or clustered centrosomes. Hematological and neurological expressed 1 (HN1) also known as Jupiter Microtubule Associated Homolog 1 (JPT1) belongs to a small poorly understood family of genes that are evolutionarily conserved across vertebrate species. The co-expression network of HN1 from the TCGA PRAD dataset indicates the putative role of HN1 in centrosome-related processes in the context of prostate cancer. HN1 expression is low in normal RWPE-1 cells as compared to cancerous androgen-responsive LNCaP and androgen insensitive PC-3 cells. HN1 overexpression resulted in differential response for cell proliferation and cell cycle changes in RWPE-1, LNCaP, and PC-3 cells. Since HN1 overexpression increased the proliferation rate in PC-3 cells, these cells were used for functional characterization of HN1 in advanced prostate carcinogenesis. Furthermore, alterations in HN expression led to an increase in abnormal to normal nuclei ratio and increased chromosomal aberrations in PC-3 cells. We observed the co-localization of HN1 with γ-tubulin foci in prostate cancer cells, further validated by immunoprecipitation. HN1 was observed as physically associated with γ-tubulin and its depletion led to increased γ-tubulin foci and disruption in microtubule spindle assembly. Higher HN1 expression was correlated with prostate cancer as compared to normal tissues. The restoration of HN1 expression after silencing suggested that it has a role in centrosome clustering, implicating a potential role of HN1 in cell division as well as in prostate carcinogenesis warranting further studies.

Dissecting pharmacological effects of chloroquine in cancer treatment: interference with inflammatory signaling pathways.

Chloroquines are 4-aminoquinoline-based drugs mainly used to treat malaria. At pharmacological concentrations, they have significant effects on tissue homeostasis, targeting diverse signaling pathways in mammalian cells. A key target pathway is autophagy, which regulates macromolecule turnover in the cell. In addition to affecting cellular metabolism and bioenergetic flow equilibrium, autophagy plays a pivotal role at the interface between inflammation and cancer progression. Chloroquines consequently have critical effects in tissue metabolic activity and importantly, in key functions of the immune system. In this article, we will review the work addressing the role of chloroquines in the homeostasis of mammalian tissue, and the potential strengths and weaknesses concerning their use in cancer therapy.

Decreased expression of EFS is correlated with the advanced prostate cancer.

Prostate cancer is the most frequently diagnosed malignant neoplasm in men in the developed countries. Although the progression of prostate cancer and the processes of invasion and metastasis by tumor cells are comparatively well understood, the genes involved in these processes are not fully determined. Therefore, a common area of research interest is the identification of novel molecules that are involved in these processes. In the present study, we have used in silico and experimental approaches to compare the expression of embryonal Fyn-associated substrate (EFS) between normal prostate and prostate cancer. We showed that EFS expression is remarkably downregulated in prostate cancer cells, compared to normal prostate cells. We also found that decreased expression of EFS in prostate cancer cells is due to DNA methylation. In addition, we showed that high EFS expression is important to suppress a malignant behavior of prostate cancer cells. Therefore, we suggest that EFS should be considered as a novel tumor suppressor gene in prostate cancer.

HN1 negatively influences the ß-catenin/E-cadherin interaction, and contributes to migration in prostate cells.

Previously, it has been reported that HN1 is involved in cytoplasmic retention and degradation of androgen receptor in an AKT dependent manner. As HN1 is a hormone inducible gene, and has been shown that it is upregulated in various cancers, we studied the importance of HN1 function in ß-catenin signaling in prostate cancer cell line, PC-3 and mammary cancer cell line MDA-MB231. Here, we demonstrated that HN1 physically associates with GSK3ß/ß-catenin destruction complex and abundantly localizes to cytoplasm, especially when the GSK3ß is phosphorylated on S9 residue. Further, ectopic HN1 expression results an increase in the ß-catenin degradation leading to loss of E-cadherin interaction, concurrently contributing to actin re-organization, colony formation and migration in cancer cell lines. Thus, we report that HN1 is an essential factor for ß-catenin turnover and signaling, augments cell growth and migration in prostate cancer cells.

Organochlorine pesticides and antioxidant enzymes are inversely correlated with liver enzyme gene expression in Cyprinus carpio.

The present study was designed to investigate the association between levels of organochlorine pesticides (OCPs) and liver enzyme responses in Cyprinus carpio. Fish were caught at three stations in the Büyük Menderes River (BMR): the origin, the Sarayköy station, and the estuary. Seventeen OCPs were quantified in liver tissue, as well as in river water by gas chromatography (GC)-electron capture detection, and structures were confirmed by negative chemical ionization-GC-mass spectrometry. The activities of CYP1A, GST, Se-GPx, CAT, and SODs were determined by spectrophotometry or fluorimetry. The mRNA levels of CYP1A, GST, and SOD1 were quantified by real-time RT-PCR. CYP1A and antioxidant enzyme activities were dramatically higher at the Sarayköy station, where OCP pollution is higher than the other two stations. Mn-SOD is responsible for the increase in total SOD activity in the Sarayköy samples. However, gene expression levels of certain enzymes were heavily suppressed. Our findings show that the transcriptional and functional responses of CYP1A and antioxidant enzymes are inversely correlated.

HOXB13 contributes to G1/S and G2/M checkpoint controls in prostate.

HOXB13 is a homeobox protein that is expressed in normal adult prostate and colon tissues; however, its deregulated expression was evidenced in various malignancies. To characterize the putative role of HOXB13 in cell cycle progression, we performed overexpression and siRNA-mediated knockdown studies in PC-3 and LNCaP cells. Immunohistochemistry (IHC) analyses were also performed using formalin-fixed, paraffin-embedded tissues containing normal, H-PIN and PCa sections from 20 radical prostatectomy specimens. Furthermore, when the role of HOXB13 during cell cycle progression, association with cyclins, cell growth and colony formation using real-time cell proliferation were assessed, we observed that ectopic expression of HOXB13 accumulated cells at G1 through decreasing the cyclin D1 level by promoting its ubiquitination and degradation. This loss slowed S phase entry in both cell lines examined, with an associated decrease in pRb((S780) and (S795)) phosphorylations. Contrary, siRNA-mediated depletion of HOXB13 expression noticeably increased cyclin levels, stabilized E2F1 and CDC25C, subsequent to increased pRb phosphorylations. This increase in Cyclin B1 and CDC25C both together facilitated activation of cyclin B complex via dephosphorylating CDK1((T14Y15)), and resumed the G2/M transition after nocodazole synchronization. Despite an increase in the total expression level and cytoplasmic retention of HOXB13 in H-PIN and PCa samples that were observed via IHC evaluation of prostate tissues, HOXB13 depletion facilitated to an increase in PC-3 and LNCaP cell proliferation. Thus, we suggest that HOXB13 expression is required for cell cycle regulation, and increases by an unknown mechanism consequent to its functional loss in cancer.

Inflammation-mediated abrogation of androgen signaling: an in vitro model of prostate cell inflammation.

As a link between inflammation and cancer has been reported in many studies, we established an in vitro model of prostatic inflammation to investigate the loss of androgen receptor (AR)-mediated signaling in androgen responsive prostate cell lines. First, the U937 monocyte cell line was differentiated into macrophages using phorbol acetate (PMA), and cells were induced with lipopolysaccharide (LPS) for cytokine secretion. Next, the cytokine levels (TNFα, IL-6, and IL1ß) in conditioned media (CM) were analyzed. Prostate cells were then fed with CM containing varying concentrations of TNFα, and IkB degradation, nuclear factor kappa B (NFκB) translocation and transactivation, and the expression of matrix metalloproteinase-8 (MMP8) and matrix metalloproteinase-9 (MMP9) were then assessed. As a result of CM treatment, ubiquitin-mediated AR degradation, which was restored using anti-TNFα antibody neutralization, led to both a decrease in KLK4, PSA, and NKX3.1 expression levels and the upregulation of GPX2. In addition to the loss of AR, acute and chronic CM exposure resulted in p53 degradation and consequent p21 downregulation, which was also restored by either androgen administration or ectopic NKX3.1 expression via the stabilization of MDM2 levels in LNCaP cells. Additionally, CM treatment enhanced H2AX((S139)) phosphorylation (a hallmark of DNA damage) and genetic heterogeneity in the absence of androgens in prostate cells without activating mitochondrial apoptosis. Thus, the data suggest that inflammatory cytokine exposure results in the loss of AR and p53 signaling in prostate cells and facilitates genetic heterogeneity via ROS accumulation to promote prostate carcinogenesis.

Identification of new genes downregulated in prostate cancer and investigation of their effects on prognosis.

Prostate cancer is the most common noncutaneous malignant neoplasm in men in the Western countries. It is well established that genetic and epigenetic alterations are common events in prostate cancer, which may lead to aberrant expression of critical genes. Most of the studies are focused on the overexpressed or duplicated genes in prostate cancer. However, it is known that some of the differentially expressed genes in prostate cancer are downregulated. Since the inventory of downregulated genes is incomplete, we performed in silico approaches to reveal the novel prostate cancer downregulated genes. Moreover, we also investigated for a possible link between the expression of the downregulated genes and tumor grade, recurrence, metastasis, or survival status in prostate cancer. Our results showed that the expression of GSTP1 and AOX1 are downregulated in prostate cancer, in concordance with previous reports. Moreover, we showed that TPM2, CLU, and COL4A6 mRNA levels are downregulated in prostate cancer. Further, we found a significant negative correlation between the expression of the above-mentioned genes and the prognosis of prostate cancer.

Meta-analysis of the cell cycle related C12orf48

The cell cycle is a conserved process from yeast to mammals and focuses on mechanisms that regulate the timing and frequency of DNA replication and cell division. The temporal and spatial expression of the genes is tightly regulated to ensure accurate replication and transmission of DNA to daughter cells during the cycle. Although the genes involved in interphase are well studied, most of the genes which are involved in mitotic events still remain unidentified. Since, the discovery of mitosis related genes is still incomplete, we performed a co-expression and gene ontology analysis for revealing novel mitosis regulated genes. In this study, we showed that C12orf48 is co-expressed with well-known mitotic genes. Moreover, it is also co-expressed with the genes that have roles in interphase such as DNA replication. Furthermore, our results showed that C12orf48 is also differentially expressed in various cancers. Therefore, the results presented in this study suggest that C12orf48 may be an important molecule for both interphase and mitosis. Since, the molecules involved in these mechanisms are crucial for proliferation as well as in carcinogenesis, C12orf48 should be considered as a novel cell cycle and carcinogenesis related gene.(AU)

Meta-analysis of the cell cycle related C12orf48

The cell cycle is a conserved process from yeast to mammals and focuses on mechanisms that regulate the timing and frequency of DNA replication and cell division. The temporal and spatial expression of the genes is tightly regulated to ensure accurate replication and transmission of DNA to daughter cells during the cycle. Although the genes involved in interphase are well studied, most of the genes which are involved in mitotic events still remain unidentified. Since, the discovery of mitosis related genes is still incomplete, we performed a co-expression and gene ontology analysis for revealing novel mitosis regulated genes. In this study, we showed that C12orf48 is co-expressed with well-known mitotic genes. Moreover, it is also co-expressed with the genes that have roles in interphase such as DNA replication. Furthermore, our results showed that C12orf48 is also differentially expressed in various cancers. Therefore, the results presented in this study suggest that C12orf48 may be an important molecule for both interphase and mitosis. Since, the molecules involved in these mechanisms are crucial for proliferation as well as in carcinogenesis, C12orf48 should be considered as a novel cell cycle and carcinogenesis related gene.