SALL4 as a new biomarker for early colorectal cancers

Inflammation-Associated Stem Cells in Gastrointestinal Cancers: Their Utility as Prognostic Biomarkers and Therapeutic Targets

Stem cells are critical for the development and homeostasis of the gastrointestinal (GI) tract. Inflammatory molecules are known to regulate the activity of stem cells. A comprehensive review specifically describing the role of inflammatory molecules in the regulation of stem cells within the GI tract and in GI cancers (GICs) is not available. This review focuses on understanding the role of inflammatory molecules and stem cells in maintaining homeostasis of the GI tract. We further discuss how inflammatory conditions contribute to the transformation of stem cells into tumor-initiating cells. We also describe the molecular mechanisms of inflammation and stem cell-driven progression and metastasis of GICs. Furthermore, we report on studies describing the prognostic value of cancer stem cells and the clinical trials evaluating their therapeutic utility. This review provides a detailed overview on the role of inflammatory molecules and stem cells in maintaining GI tract homeostasis and their implications for GI-related malignancies.

Colorectal cancer screening: A review of current knowledge and progress in research

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide, being the third most commonly diagnosed malignancy and the second leading cause of cancer-related deaths globally. Despite the progress in screening, early diagnosis, and treatment, approximately 20%-25% of CRC patients still present with metastatic disease at the time of their initial diagnosis. Furthermore, the burden of disease is still expected to increase, especially in individuals younger than 50 years old, among whom early-onset CRC incidence has been increasing. Screening and early detection are pivotal to improve CRC-related outcomes. It is well established that CRC screening not only reduces incidence, but also decreases deaths from CRC. Diverse screening strategies have proven effective in decreasing both CRC incidence and mortality, though variations in efficacy have been reported across the literature. However, uncertainties persist regarding the optimal screening method, age intervals and periodicity. Moreover, adherence to CRC screening remains globally low. In recent years, emerging technologies, notably artificial intelligence, and non-invasive biomarkers, have been developed to overcome these barriers. However, controversy exists over the actual impact of some of the new discoveries on CRC-related outcomes and how to effectively integrate them into daily practice. In this review, we aim to cover the current evidence surrounding CRC screening. We will further critically assess novel approaches under investigation, in an effort to differentiate promising innovations from mere novelties.

SALL4 in gastrointestinal tract cancers: upstream and downstream regulatory mechanisms

Effective therapeutic targets and early diagnosis are major challenges in the treatment of gastrointestinal tract (GIT) cancers. SALL4 is a well-known transcription factor that is involved in organogenesis during embryonic development. Previous studies have revealed that SALL4 regulates cell proliferation, survival, and migration and maintains stem cell function in mature cells. Additionally, SALL4 overexpression is associated with tumorigenesis. Despite its characterization as a biomarker in various cancers, the role of SALL4 in GIT cancers and the underlying mechanisms are unclear. We describe the functions of SALL4 in GIT cancers and discuss its upstream/downstream genes and pathways associated with each cancer. We also consider the possibility of targeting these genes or pathways as potential therapeutic options for GIT cancers.

Tumor circulating biomarkers in colorectal cancer

CRC is a major global health concern and is responsible for a significant number of cancer-related deaths each year. The successful treatment of CRC becomes more difficult when it goes undetected until it has advanced to a later stage. Diagnostic biomarkers can play a critical role in the early detection of CRC, which leads to improved patient outcomes and increased survival rates. It is important to develop reliable biomarkers for the early detection of CRC to enable timely diagnosis and treatment. To date, CRC detection methods such as endoscopy, blood, and stool tests are imperfect and often only identify cases in the later stages of the disease. To overcome these limitations, researchers are turning to molecular biomarkers as a promising avenue for improving CRC detection. Diagnostic information can be provided more reliably through a noninvasive approach using biomarkers such as mRNA, circulating cell-free DNA, micro-RNA, long non-coding RNA, and proteins. These biomarkers can be found in blood, tissue, feces, and volatile organic compounds. The identification of molecular biomarkers with high sensitivity and specificity for early detection of CRC that are safe, cost-effective, and easily measurable remains a significant challenge for researchers. In this article, we will explore the latest advancements in blood-based diagnostic biomarkers for CRC and their potential impact on improving patient survival rates.

Current advances in detecting genetic and epigenetic biomarkers of colorectal cancer

Colorectal carcinoma (CRC) is the third most common cancer in terms of diagnosis and the second in terms of mortality. Recent studies have shown that various proteins, extracellular vesicles (i.e., exosomes), specific genetic variants, gene transcripts, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and altered epigenetic patterns, can be used to detect, and assess the prognosis of CRC. Over the last decade, a plethora of conventional methodologies (e.g., polymerase chain reaction [PCR], direct sequencing, enzyme-linked immunosorbent assay [ELISA], microarray, in situ hybridization) as well as advanced analytical methodologies (e.g., microfluidics, electrochemical biosensors, surface-enhanced Raman spectroscopy [SERS]) have been developed for analyzing genetic and epigenetic biomarkers using both optical and non-optical tools. Despite these methodologies, no gold standard detection method has yet been implemented that can analyze CRC with high specificity and sensitivity in an inexpensive, simple, and time-efficient manner. Moreover, until now, no study has critically reviewed the advantages and limitations of these methodologies. Here, an overview of the most used genetic and epigenetic biomarkers for CRC and their detection methods are discussed. Furthermore, a summary of the major biological, technical, and clinical challenges and advantages/limitations of existing techniques is also presented.

SALL4 advances the proliferation and tumor cell stemness of colon cancer cells through the transcription and regulation of ROBO2

SALL4 is a transcription factor highly expressed in diverse cancers and is implicated in the development of cancer. SALL4 has been implied to play a cancer-promoting role in colon cancer (CC), but the molecular mechanism remains unclear. Chromatin immunoprecipitation assay and dual-luciferase assay were conducted to verify the binding relationship of SALL4 and ROBO2. qRT-PCR detected the mRNA expression levels of SALL4 and ROBO2, and the flow cytometry analyzed the cell cycle distribution. Western blot examined SALL4 expression, and cell cycle/cell stemness-related proteins. The impact of SALL4 and ROBO2 on the proliferation capacity of cells and tumor cell stemness was elucidated by MTT, colony formation, and sphere-forming assays. SALL4 and ROBO2 were up-regulated in CC, and SALL4 could activate the transcription of ROBO2. Down-regulated SALL4 was able to significantly restrain the proliferation capacity of CC cells and arrest the cell cycle in G0/G1 phase by repressing the expression of cyclin B, cyclin E, and cyclin D1. Besides, the rescue assay results indicated that up-regulated ROBO2 could reverse the repressive impact of down-regulated SALL4 on the proliferation of CC cells and accelerate the progression of the cell cycle, thus promoting the sphere-forming of tumor stem cells. SALL4 advanced the proliferation of CC and cell stemness through direct activation of ROBO2 expression, implied the novel mechanism of SALL4 in CC, and pointed out that SALL4/ROBO2 axis was likely to be a potential target for clinical treatment of CC.

Dual-Regulated Mechanism of EZH2 and KDM6A on SALL4 Modulates Tumor Progression via Wnt/β-Catenin Pathway in Gastric Cancer

BACKGROUND

SALL4 has been demonstrated in many cancers and participated in tumorigenesis and tumor progression, however, its expression and function still remain ambiguous in GC, especially its upstream mechanistic modulators.

PURPOSE

We explored whether the dual mediation of EZH2 and KDM6A could be involved in upstream regulation of SALL4, which promotes GC cell progression via the Wnt/β-catenin pathway.

METHOD

Analysis of discrepant gene expression in GC and normal gastric tissues from The Cancer Genome Atlas (TCGA) dataset. GC cell lines were transfected by siEZH2 and siKDM6A, the transduction molecules of KDM6A/EZH2-SALL4-β-catenin signaling were quantified in the GC cells.

RESULTS

Here, we showed that only SALL4 levels of SALL family members were upregulated in nonpaired and paired GC tissues than those in corresponding normal tissues and were associated with its histological types, pathological stages, TNM stages including T stage (local invasion), N stage (lymph node metastasis), M stage (distant metastasis), and overall survival from the TCGA dataset. SALL4 level was elevated in GC cells compared to normal gastric epithelial cell line (GES-1) and was correlated to cancer cell progression and invasion through the Wnt/β-catenin pathway in GC, which levels would be separately upregulated or downregulated by KDM6A or EZH2.

CONCLUSION

We first proposed and demonstrated that SALL4 promoted GC cell progression via the Wnt/β-catenin pathway, which was mediated by the dual regulation of EZH2 and KDM6A on SALL4. This mechanistic pathway in gastric cancer represents a novel targetable pathway.

Diagnostic and prognostic biomarkers in colorectal cancer and the potential role of exosomes in drug delivery

Colorectal cancer (CRC) is the third most common cancer with the second most frequent cause of death worldwide. One fourth to one fifth of the CRC cases are detected at advance stage. Early detection of colorectal cancer might help in decreasing mortality and morbidity worldwide. CRC being a heterogeneous disease, new non-invasive approaches are needed to complement and improve the screening and management of CRC. Reliable and early detectable biomarkers would improve diagnosis, prognosis, therapeutic responses, and will enable the prediction of drug response and recurrence risk. Over the past decades molecular research has demonstrated the potentials of CTCs, ctDNAs, circulating mRNAs, ncRNAs, and exosomes as tumor biomarkers. Non-invasive screening approaches using fecal samples for identification of altered gut microbes in CRC is also gaining attention. Exosomes can be potential candidates that can be employed in the drug delivery system. Further, the integration of in vitro, in vivo and in silico models that involve CRC biomarkers will help to understand the interactions occurring at the cellular level. This review summarizes recent update on CRC biomarkers and their application along with the nanoparticles followed by the application of organoid culture in CRC.

Dysregulated Expression of Three Genes in Colorectal Cancer Stratifies Patients into Three Risk Groups

Despite advances in recent years in the study of the molecular profile of sporadic colorectal cancer (sCRC), the specific genetic events that lead to increased aggressiveness or the development of the metastatic process of tumours are not yet clear. In previous studies of the gene expression profile (GEP) using a high-density array (50,000 genes and 6000 miRNAs in a single assay) in sCRC tumours, we identified a 28-gene signature that was found to be associated with an adverse prognostic value for predicting patient survival. Here, we analyse the differential expression of these 28 genes for their possible association with tumour local aggressiveness and metastatic processes in 66 consecutive sCRC patients, followed for >5 years, using the NanoString nCounter platform. The global transcription profile (expression levels of the 28 genes studied simultaneously) allowed us to discriminate between sCRC tumours and nontumoral colonic tissues. Analysis of the biological and functional significance of the dysregulated GEPs observed in our sCRC tumours revealed 31 significantly altered canonical pathways. Among the most commonly altered pathways, we observed the increased expression of genes involved in signalling pathways and cellular processes, such as the PI3K-Akt pathway, the interaction with the extracellular matrix (ECM), and other functions related to cell signalling processes (SRPX2). From a prognostic viewpoint, the altered expression of BST2 and SRPX2 genes were the only independent variables predicting for disease-free survival (DFS). In addition to the pT stage at diagnosis, dysregulated transcripts of ADH1B, BST2, and FER1L4 genes showed a prognostic impact on OS in the multivariate analysis. Based on the altered expression of these three genes, a scoring system was built to stratify patients into low-, intermediate-, and high-risk groups with significantly different 5-year OS rates: 91%, 83%, and 52%, respectively. The prognostic impact was validated in two independent series of sCRC patients from the public GEO database (n = 562 patients). In summary, we show a strong association between the altered expression of three genes and the clinical outcome of sCRC patients, making them potential markers of suitability for adjuvant therapy after complete tumour resection. Additional prospective studies in larger series of patients are required to confirm the clinical utility of the newly identified biomarkers because the number of patients analysed remains small.

SALL4: An Intriguing Therapeutic Target in Cancer Treatment

Spalt-Like Transcription Factor 4 (SALL4) is a critical factor for self-renewal ability and pluripotency of stem cells. On the other hand, various reports show tight relation of SALL4 to cancer occurrence and metastasis. SALL4 exerts its effects not only by inducing gene expression but also repressing a large cluster of genes through interaction with various epigenetic modifiers. Due to high expression of SALL4 in cancer cells and its silence in almost all adult tissues, it is an ideal target for cancer therapy. However, targeting SALL4 meets various challenges. SALL4 is a transcription factor and designing appropriate drug to inhibit this intra-nucleus component is challenging. On the other hand, due to lack of our knowledge on structure of the protein and the suitable active sites, it becomes more difficult to reach the appropriate drugs against SALL4. In this review, we have focused on approaches applied yet to target this oncogene and discuss the potential of degrader systems as new therapeutics to target oncogenes.

Co-overexpression of self-renewal markers SALL4 and HIWI is correlated with depth of tumor invasion and metastasis in colorectal cancer

Background

SALL4 and HIWI are involved in the maintenance of self-renewal capacity of stem cells. Several scrutinizes have demonstrated that SALL4 and HIWI play a key role in cancer development. However, the correlation between these genes regarding different clinicopathological features of patients with colorectal cancer (CRC) is still unclear.

Methods

The expression of SALL4 and HIWI in different clinicopathological features of 46 CRC patients was analyzed using relative comparative real-time PCR.

Results

mRNA expression levels of SALL4 and HIWI genes were significantly correlated with each other in CRC (P = 0.013, Pearson correlation = 0.364). HIWI expression was notably increased in tumors with overexpression of SALL4 in comparison with other samples. This correlation was significant in non-metastatic CRCs compared to the metastatic tumors and in invaded tumors to the serosa (T3/T4) in comparison with non-invaded tumors (T1/T2).

Conclusions

Based on the significant association of SALL4 and HIWI in different indices of CRC poor prognosis, it may be concluded that simultaneous expression of these genes is notably contributed to the growth and development of the disease, and therefore, their co-overexpression may be considered for prognosis of aggressive CRCs.

Identification of gene signatures for COAD using feature selection and Bayesian network approaches

The combination of TCGA and GTEx databases will provide more comprehensive information for characterizing the human genome in health and disease, especially for underlying the cancer genetic alterations. Here we analyzed the gene expression profile of COAD in both tumor samples from TCGA and normal colon tissues from GTEx. Using the SNR-PPFS feature selection algorithms, we discovered a 38 gene signatures that performed well in distinguishing COAD tumors from normal samples. Bayesian network of the 38 genes revealed that DEGs with similar expression patterns or functions interacted more closely. We identified 14 up-DEGs that were significantly correlated with tumor stages. Cox regression analysis demonstrated that tumor stage, STMN4 and FAM135B dysregulation were independent prognostic factors for COAD survival outcomes. Overall, this study indicates that using feature selection approaches to select key gene signatures from high-dimensional datasets can be an effective way for studying cancer genomic characteristics.

Contribution of TWIST1-EVX1 Axis in Invasiveness of Esophageal Squamous Cell Carcinoma; a Functional Study

BACKGROUND

Epithelial-mesenchymal transition (EMT) is a biological process in embryonic development and cancer progression, and different gene families, such as HOX genes, are closely related to this process.

OBJECTIVES

Our aim in this study was to investigate the correlation between TWIST1 and EVX1 mRNA expression in ESCC patients and also examine the probable regulatory function of TWIST1 on EVX1 expression in human ESCC cell line.

MATERIALS AND METHODS

TWIST1 and EVX1 gene expression patterns were assessed in ESCC patients by relative comparative Real-time PCR then correlated with their clinical characteristics. In silico analysis of the EVX1 gene was conducted. KYSE-30 cells were transduced by a retroviral system to ectopically express TWIST1, followed by qRT-PCR to reveal the correlation between TWIST1 and EVX1 gene expression.

RESULTS

The expression of TWIST1 and EVX1 was correlated to each other significantly (p=0.005) in ESCC. Of 28 patients with under/normal expression of TWIST1, 22 samples (78.57%) had over/normal expression of EVX1. TWIST1 overexpression was correlated with advanced stages of the tumor (III, IV) (P = 0.019) and lymph node metastasis. However, EVX1 under expression was associated with lymph node metastasis (p = 0.027) and invasiveness of the disease (P = 0.037) in ESCC. Furthermore, retroviral transduction enforced significant overexpression of TWIST1 in GFP-hTWIST-1 approximately 9-fold compared to GFP control cells, causing a - 8.83- fold reduction in EVX1 mRNA expression significantly.

CONCLUSIONS

Our results indicated the repressive role of TWIST1 on EVX1 gene expression in ESCC. Therefore, our findings can help dissect the molecular mechanism of ESCC tumorigenesis and discover novel therapeutic targets for ESCC invasion and metastasis.

Evaluating the effect of conditioned medium from endometrial stem cells on endometriosis-derived endometrial stem cells

Endometriosis is a common, benign gynecological disease which is determined as an overspreading of endometrial tissue in exterior region of the uterine cavity. Evidence suggests that retrograde menstrual blood which contains mesenchymal stem cells with differential gene expression compared to healthy women may play a role in endometriosis creation. We aimed to identify whether the conditioned medium (CM) from menstrual blood-derived mesenchymal stem cells (MenSCs) of healthy women can affect the expression level of inflammatory and stemness genes of MenSCs from endometriosis women. Endometriosis-derived MenSCs (E-MenSCs) were treated with CM derived from healthy women's MenSCs (non-endometriosis derived MenSCs [NE-MenSCs]). Some CD markers were analyzed by flow cytometer before and after treatment compared with NE-MenSCs, and the expression level of inflammatory and stemness genes was evaluated by real-time PCR. E-MenSCs show different morphology in vitro culture in comparison with NE-MenSCs, which were changed in the presence of CM, into a morphology more similar to normal cells and showed significant decrease expression of CD10 after CM treatment. In our results, the interleukin-1, cyclooxygenase-2, and hypoxia-inducible factor 1α as inflamaturay genes and octamer-binding transcription factor 4, NANOG, and sex determining region Y-box 2 as stemness genes showed significantly different expression level in E-MenSCs after treating with CM. Our study indicates that the expression level of some inflammatory- and stemness-related genes which have differential expression in E-MenSCs compared with NEMenSCs, could be changed to normal status by using CM derived from NE-MenSCs.

SALL4 Oncogenic Function in Cancers: Mechanisms and Therapeutic Relevance

SALL4, a member of the SALL family, is an embryonic stem cell regulator involved in self-renewal and pluripotency. Recently, SALL4 overexpression was found in malignant cancers, including lung cancer, hepatocellular carcinoma, breast cancer, gastric cancer, colorectal cancer, osteosarcoma, acute myeloid leukemia, ovarian cancer, and glioma. This review updates recent advances of our knowledge of the biology of SALL4 with a focus on its mechanisms and regulatory functions in tumors and human hematopoiesis. SALL4 overexpression promotes proliferation, development, invasion, and migration in cancers through activation of the Wnt/β-catenin, PI3K/AKT, and Notch signaling pathways; expression of mitochondrial oxidative phosphorylation genes; and inhibition of the expression of the Bcl-2 family, caspase-related proteins, and death receptors. Additionally, SALL4 regulates tumor progression correlated with the immune microenvironment involved in the TNF family and gene expression through epigenetic mechanisms, consequently affecting hematopoiesis. Therefore, SALL4 plays a critical oncogenic role in gene transcription and tumor growth. However, there are still some scientific hypotheses to be tested regarding whether SALL4 is a therapeutic target, such as different tumor microenvironments and drug resistance. Thus, an in-depth understanding and study of the functions and mechanisms of SALL4 in cancer may help develop novel strategies for cancer therapy.

A pan-cancer study of spalt-like transcription factors 1/2/3/4 as therapeutic targets

Spalt-like transcription factors (SALLs) are evolutionarily conserved proteins that participate in embryonic development. Four members of the SALL family, SALL1, SALL2, SALL3, and SALL4, are involved in cellular apoptosis, angiogenesis, invasion, and metastasis of tumors. We used the TCGA pan-cancer data to conduct a comprehensive analysis of SALL genes. High heterogeneity in the expression of these genes was observed across various cancers, SALL1 and SALL2 were downregulated, whereas SALL4 was upregulated. Moreover, we verified that SALL4 was commonly associated with survival disadvantage, whereas others were linked to a better prognosis. In renal cancer, SALL1, SALL2, and SALL3 showed downregulation, suggesting that they acted as tumor suppressors. Furthermore, SALLs were associated with immune infiltrate subtypes, with a close association between different degrees of infiltration of stromal cells and immune cells. DNA and RNA analyses in different tumors suggested different degrees of negative or positive correlation with tumor stem cell-like features. Finally, we revealed that SALLs were related to cancer cell resistance. Our results highlight the necessity to further study each SALL gene as a separate entity in specific types of cancer. Although this article showed that SALLs could be promising targets for cancer therapy, it needs further studies to validate the findings.

Circulating PTGS2, JAG1, GUCY2C and PGF mRNA in Peripheral Blood and Serum as Potential Biomarkers for Patients with Metastatic Colon Cancer

Genes involved in the angiogenic process have been proposed for the diagnosis and therapeutic response of metastatic colorectal cancer (CRC). This study aimed to investigate the value of PTGS2, JAG1, GUCY2C and PGF-circulating RNA as biomarkers in metastatic CRC. Blood cells and serum mRNA from 59 patients with metastatic CRC and 47 healthy controls were analyzed by digital PCR. The area under the receiver operating characteristic curve (AUC) was used to estimate the diagnostic value of each mRNA alone or mRNA combinations. A significant upregulation of the JAG1, PTGS2 and GUCY2C genes in blood cells and serum samples from metastatic CRC patients was detected. Circulating mRNA levels in the serum of all genes were significantly more abundant than in blood. The highest discrimination ability between metastatic CRC patients and healthy donors was obtained with PTGS2 (AUC of 0.984) and GUCY2C (AUC of 0.896) in serum samples. Biomarker combinations did not improve the discriminatory capacity of biomarkers separately. Analyzed biomarkers showed no correlation with overall survival or progression-free survival, but GUCY2C and GUCY2C/PTGS2 expression in serum correlated significantly with the response to antiangiogenic agents. These findings demonstrate that assessment of genes involved in the angiogenic process may be a potential non-invasive diagnostic tool for metastatic CRC and its response to antiangiogenic therapy.

Role of miRNA gene variants in the susceptibility and pharmacogenetics of colorectal cancer

Colorectal cancer (CRC) is one of the most significant challenges in the field of cancer pathology. miRNAs are among the genetic factors associated with the disease. Although many studies have reviewed the expression patterns of various miRNAs in CRC, few studies have focused on different variants of miRNA. In the present review, miRNA variants have been categorized into three subgroups, including miRNA variants that predict susceptibility to CRC, miRNA variants that predict the clinical parameters of CRC and finally, miRNA variants that predict the pharmacological aspects of CRC. Moreover, a comprehensive review of potentially functional miRNA-associated SNPs as well as their importance as candidate cancer biomarkers are discussed.

TWIST1 upregulates matrix metalloproteinase (MMP) genes family in esophageal squamous carcinoma cells

Twist-related protein 1 (TWIST1), a highly conserved basic helix-loop-helix transcription factor, stimulates epithelial-mesenchymal transition (EMT) and plays a crucial role in the regulation of the extracellular matrix (ECM) and cell-cell adhesion. Our aim in this study was to evaluate the functional correlation between TWIST1 and MMP genes in human ESCC cell lines, KYSE-30 and YM-1. To generate recombinant retroviral particles, the Pruf-IRES-GFP-hTWIST1 was co-transfected into HEK293T along with pGP and pMD2. G as well as Pruf-IRES-GFP control plasmid. Stably transduced high-expressing GFP-hTWIST1 and GFP-control KYSE-30 cells were generated. The produced retroviral particles were transduced into the KYSE-30 and YM-1 ESCC cells. Ectopic expression of TWIST1 mRNA and expression of the MMP genes (MMP-2, MMP-3, MMP-7, MMP-9, and MMP-10) were examined by relative comparative real-time PCR. In silico analysis of the MMP markers and their promoter elements was explored. Moreover, the scratch wound assay was used to evaluate the migration of TWIST1-induced cells. TWIST1 level was up-regulated by nearly 5-fold and 7.4-fold in GFP-hTWIST1 KYSE-30 and YM-1 cells compared to GFP control cells, respectively. Interestingly, this enforced expression of TWIST1 subsequently caused significant overexpression of transcripts for selected MMP genes in GFP-hTWIST1 in comparison with GFP control cells in both ESCC cell lines. Also, the scratch assay indicated that TWIST1 expression effectively increased the migration of GFP-TWIST1 KYSE-30 cells against GFP KYSE-30 control cells in vitro. The present findings illuminate that TWIST1 may contribute broadly to ESCC development in concert with up-regulation of MMPs expression and further suggest the potential advantage of exerting TWIST1/MMPs signaling axis as a framework from which to expand our understanding about the mechanisms of ESCC tumorigenesis.

Cancer Stem Cells-Origins and Biomarkers: Perspectives for Targeted Personalized Therapies

The use of biomarkers in diagnosis, therapy and prognosis has gained increasing interest over the last decades. In particular, the analysis of biomarkers in cancer patients within the pre- and post-therapeutic period is required to identify several types of cells, which carry a risk for a disease progression and subsequent post-therapeutic relapse. Cancer stem cells (CSCs) are a subpopulation of tumor cells that can drive tumor initiation and can cause relapses. At the time point of tumor initiation, CSCs originate from either differentiated cells or adult tissue resident stem cells. Due to their importance, several biomarkers that characterize CSCs have been identified and correlated to diagnosis, therapy and prognosis. However, CSCs have been shown to display a high plasticity, which changes their phenotypic and functional appearance. Such changes are induced by chemo- and radiotherapeutics as well as senescent tumor cells, which cause alterations in the tumor microenvironment. Induction of senescence causes tumor shrinkage by modulating an anti-tumorigenic environment in which tumor cells undergo growth arrest and immune cells are attracted. Besides these positive effects after therapy, senescence can also have negative effects displayed post-therapeutically. These unfavorable effects can directly promote cancer stemness by increasing CSC plasticity phenotypes, by activating stemness pathways in non-CSCs, as well as by promoting senescence escape and subsequent activation of stemness pathways. At the end, all these effects can lead to tumor relapse and metastasis. This review provides an overview of the most frequently used CSC markers and their implementation as biomarkers by focussing on deadliest solid (lung, stomach, liver, breast and colorectal cancers) and hematological (acute myeloid leukemia, chronic myeloid leukemia) cancers. Furthermore, it gives examples on how the CSC markers might be influenced by therapeutics, such as chemo- and radiotherapy, and the tumor microenvironment. It points out, that it is crucial to identify and monitor residual CSCs, senescent tumor cells, and the pro-tumorigenic senescence-associated secretory phenotype in a therapy follow-up using specific biomarkers. As a future perspective, a targeted immune-mediated strategy using chimeric antigen receptor based approaches for the removal of remaining chemotherapy-resistant cells as well as CSCs in a personalized therapeutic approach are discussed.

MiR-3622a-3p acts as a tumor suppressor in colorectal cancer by reducing stemness features and EMT through targeting spalt-like transcription factor 4

MicroRNAs are a class of small non-coding RNAs which act as oncogenes or tumor suppressors through targeting specific mRNAs. Colorectal cancer (CRC) is one of the most common malignancies worldwide. MiR-3622a-3p is found to be decreased in colorectal cancer (CRC) by analyzing data from TCGA database and there are few reports about the role of miR-3622a-3p in cancers. Our research aimed to explore the effects of miR-3622a-3p on CRC. MiR-3622a-3p was found to be down-regulated in CRC tissues and cells by qRT-PCR. The effect of miR-3622a-3p on proliferation, apoptosis, cell cycle, migration and invasion of CRC cells were investigated by a serious of biological function assays and the results revealed that miR-3622a-3p could inhibit the malignant biological properties of CRC. We performed dual luciferase assay, RNA immunoprecipitation (RIP) assay and pull-down assay to confirm the interaction between miR-3622a-3p and spalt-like transcription factor 4 (SALL4). Western blot was carried out to determine the effects of miR-3622a-3p and SALL4 on stemness features and EMT. We found that miR-3622a-3p suppressed stemness features and EMT of CRC cells by SALL4 mRNA degradation. MiR-3622a-3p could inhibit CRC cell proliferation and metastasis in vivo with tumor xenograft model and in vivo metastasis model. The CRC organoid model was constructed with fresh CRC tissues and the growth of organoids was suppressed by miR-3622a-3p. Taken together, the results of our study indicate miR-3622a-3p exerts antioncogenic role in CRC by downregulation of SALL4. The research on miR-3622a-3p might provide a new insight into treatment of CRC.

SALL4 is a useful marker for pediatric yolk sac tumors

BACKGROUND

SALL4 is a zinc finger transcription factor that exerts its physiological role during embryo-fetal development. Analyses of SALL4 expression have shown its oncogenic role in precursor B-cell lymphoblastic lymphoma, acute and chronic myeloid leukemia, gastrointestinal, breast, and lung cancers. The aim of this study was to determine the immunohistochemical profile of SALL4 in pediatric yolk sac tumors (YSTs).

METHODS AND RESULTS

Immunohistochemistry detection of SALL4 was performed in 22 cases of pediatric YSTs and 10 mature teratomas. The percentage of tumor cells stained was scored as 0, 1+ (1-30% cells), 2+ (31-60%), 3+ (61-90%), and 4+ (> 90%). To compare its sensitivity and specificity with Glypican-3 and α-fetoprotein (AFP), we also stained tumors from these cases for Glypican-3 and AFP. In contrast to AFP and glypican-3, SALL4 staining in more than 90% of the tumor cells was seen in all 22 pediatric YSTs (100% sensitivity) (P < 0.001 for both SALL4 vs. AFP and SALL4 vs. glypican-3).

CONCLUSIONS

SALL4 is a sensitive marker for pediatric YSTs and it can be used to distinguish them from mature teratomas. SALL4 is likely to become a new and valuable biomarker for the diagnosis of pediatric YST.

Biomarkers for detecting colorectal cancer non-invasively: DNA, RNA or proteins?

Colorectal cancer (CRC) is a global problem affecting millions of people worldwide. This disease is unique because of its slow progress that makes it preventable and often curable. CRC symptoms usually emerge only at advanced stages of the disease, consequently its early detection can be achieved only through active population screening, which markedly reduces mortality due to this cancer. CRC screening tests that employ non-invasively detectable biomarkers are currently being actively developed and, in most cases, samples of either stool or blood are used. However, alternative biological substances that can be collected non-invasively (colorectal mucus, urine, saliva, exhaled air) have now emerged as new sources of diagnostic biomarkers. The main categories of currently explored CRC biomarkers are: (1) Proteins (comprising widely used haemoglobin); (2) DNA (including mutations and methylation markers); (3) RNA (in particular microRNAs); (4) Low molecular weight metabolites (comprising volatile organic compounds) detectable by metabolomic techniques; and (5) Shifts in gut microbiome composition. Numerous tests for early CRC detection employing such non-invasive biomarkers have been proposed and clinically studied. While some of these studies generated promising early results, very few of the proposed tests have been transformed into clinically validated diagnostic/screening techniques. Such DNA-based tests as Food and Drug Administration-approved multitarget stool test (marketed as Cologuard®) or blood test for methylated septin 9 (marketed as Epi proColon® 2.0 CE) show good diagnostic performance but remain too expensive and technically complex to become effective CRC screening tools. It can be concluded that, despite its deficiencies, the protein (haemoglobin) detection-based faecal immunochemical test (FIT) today presents the most cost-effective option for non-invasive CRC screening. The combination of non-invasive FIT and confirmatory invasive colonoscopy is the current strategy of choice for CRC screening. However, continuing intense research in the area promises the emergence of new superior non-invasive CRC screening tests that will allow the development of improved disease prevention strategies.

THG-1 suppresses SALL4 degradation to induce stemness genes and tumorsphere formation through antagonizing NRBP1 in squamous cell carcinoma cells

Knockdown of THG-1 in TE13 esophageal squamous cell carcinoma (ESCC) cells is known to suppress tumorsphere growth. THG-1 was identified as an NRBP1 binding protein, and NRBP1 was reported to downregulate an stemness-related transcriptional factor SALL4, so we decided to examine the possibility that tumorigenic function of THG-1 is achieved by the competition to the tumor-suppressive function of NRBP1. SALL4 was decreased in THG-1 deficient TE13 cells with reduced tumorsphere formation, while exogenous SALL4 expression in THG-1 deficient TE13 cells recovered expression of stemness genes (NANOG and OCT4) and partially, but significantly, recovered tumorsphere formation ability. Additionally, we found that NRBP1 induced ubiquitination of SALL4, and THG-1 interrupted the ubiquitination of SALL4 by antagonizing NRBP1 binding to SALL4. These results suggest that THG-1 promotes tumorsphere growth of ESCC cells by the stabilization of SALL4 protein and induction of the target stemness genes through competitive binding to NRBP1.

SALL4 promotes the tumorigenicity of cervical cancer cells through activation of the Wnt/β-catenin pathway via CTNNB1

SALL4 is overexpressed in many cancers and is found to be involved in tumorigenesis and tumor progression. However, the function of SALL4 in cervical cancer remains unknown. Here, we showed that the expression of SALL4 was gradually increased from normal cervical tissue to high-grade squamous intraepithelial lesions and then to squamous cervical carcinoma. SALL4 was upregulated or downregulated in cervical cancer cells by stably transfecting a SALL4-expressing plasmid or a shRNA plasmid targeting SALL4, respectively. In vitro, cell growth curves and MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assays showed that SALL4 promoted the cell proliferation of cervical cancer cells. In vivo, xenograft experiments verified that SALL4 enhanced the tumor formation of cervical cancer cells in female BALB/c Nude mice. Cell cycle analysis by fluorescence-activated cell sorting found that SALL4 accelerates cell cycle transition from the G0 /G1 phase to the S phase. TOP/FOP-Flash reporter assay revealed that SALL4 significantly upregulates the activity of Wnt/β-catenin pathway. Western blotting showed that the expression levels of β-catenin and important downstream genes, including c-Myc and cyclin D1, were increased by SALL4 in cervical cancer cells. Furthermore, dual-luciferase reporter and chromatin immunoprecipitation assays confirmed that SALL4 transcriptionally activated CTNNB1 by physically interacting with its promoters. Taken together, The results of this study demonstrated that SALL4 may promote cell proliferation and tumor formation of cervical cancer cells by upregulating the activity of the Wnt/β-catenin signaling pathway by directly binding to the CTNNB1 promoter and trans-activating CTNNB1.

Knockdown of Sal-like 4 expression by siRNA induces apoptosis in colorectal cancer

Colorectal cancer (CRC) is known as the third most common malignancies among men and women and is also the second leading cause of cancer-related deaths worldwide. It has been indicated that a variety of risk factors are involved in the pathogenesis of CRC. Spalt-like transcription factor 4 (SALL4) is known as a transcription factor that plays an important role in the proliferation of cancerous cells. In this study, using a specific sequence of small interfering RNA (siRNA) against the sequence of SALL4, its activity is investigated in the CRC cell line (sw742). The CRC cells (sw742) were cultured and then, using a specific anti-SALL4 siRNA, their toxic doses were determined. Then, the gene is transfected into the cell. Proliferation and expression of the SALL4 and Bcl-2 gene were measured using the real-time polymerase chain reaction method. Cell death was evaluated by propidium iodide staining and fluorescence-activated cell sorting analysis. Our results indicated that the specific concentration of siRNA of the SALL4 gene was 62.5 nmole. Gene expression of SALL4 and Bcl-2 results showed that expression of Bcl-2 gene in the siRNA group was significantly reduced. In conclusion, our finding indicated that it could be used as a therapeutic and diagnostic biomarker in the treatment of patients with CRC.

Circulating cell-free nucleic acids as biomarkers in colorectal cancer screening and diagnosis - an update

Introduction: Screening methods for one of the most frequently diagnosed malignancy, colorectal cancer (CRC), have limitations. Circulating cell-free nucleic acids (cfNA) hold clinical relevance as screening, prognostic and therapy monitoring markers. Area covered: In this review, we summarize potential CRC-specific cfNA biomarkers, the recently developed sample preparation techniques, their applications, and pitfalls. Expert opinion: Automated extraction of cfDNA is highly reproducible, however, cfDNA yield is less compared to manual isolation. Quantitative and highly sensitive detection techniques (e.g. digital PCR, NGS) can be applied to analyze genetic and epigenetic changes. Detection of DNA mutations or methylation in cfDNA and related altered levels of mRNA, miRNA, and lncRNA may improve early cancer recognition, based on specific, CRC-related patterns. Detection of cfDNA mutations (e.g. TP53, KRAS, APC) has limited diagnostic sensitivity (40-60%), however, methylated DNA including SEPT9, SFRP1, SDC2 can be applied with higher sensitivity (up to 90%) for CRC. Circulating miRNAs (e.g. miR-21, miR-92, miR-141) provide comparably high sensitivity for CRC as the circulating tumor cell mRNA markers (e.g. EGFR, CK19, CK20, CEA). Automation of cfNA isolation coupled with quantitative analysis of CRC-related, highly sensitive biomarkers may enhance CRC screening and early detection in the future.

Linkage between EMT and stemness state through molecular association between TWIST1 and NY-ESO1 in esophageal squamous cell carcinoma

Aberrant expression of cancer testis antigens (CTAs) is reported in tumors, especially those with stemness properties. A number of CTAs can induce epithelial mesenchymal transition (EMT) process and promote cancer stem cells (CSCs) characteristics. We aimed in this study to analyze the correlation between NY-ESO1 and TWIST1 in esophageal squamous cell carcinoma (ESCC), as well as their impact on EMT process. Gene expression profiling of NY-ESO1 and TWIST1 was performed in 43 esophageal tumors compared to their margin normal tissues of using qRT-PCR, and their correlation with clinicopathological variables of the patients was evaluated. In silico analysis of the NY-ESO1, epithelial and mesenchymal cell markers and also their promoter sequences was executed. ESCC cell lines KYSE-30 and YM-1 were transduced to ectopically express TWIST1 using a retroviral system, followed by qRT-PCR mRNA expression analysis to reveal the probable correlation among TWIST1, NY-ESO1 and EMT markers gene expression. Scratch assay was performed to estimate migration of TWIST1-induced cells. Overexpression of TWIST1 and NY-ESO1 mRNA was observed in 42% and 39.5% (P ˂ 0.05) of tumors, respectively. Expression of the genes was significantly correlated with each other (p = 0.005). TWIST1 and NY-ESO1 overexpression was significantly associated with stage of progression and size of tumors, respectively. A direct association between TWIST1 and NY-ESO1 mRNA expression was confirmed by induced ectopic expression of TWIST1 in ESCC cell lines KYSE-30 and YM-1. TWIST1-induced cells led to increase migration in ESCC cell line. Furthermore, significant up-regulation of EMT markers was observed following ectopic expression of TWIST1 in these cells. Based on our findings, it may be proposed that a vital association is exist between the EMT and the acquisition of cancer stemness state in tumor cells through the TWIST1/NY-ESO1 axis and it can be a critical hallmark in ESCC tumorigenesis.

Genetic and molecular origins of colorectal Cancer among the Iranians: an update

BACKGROUND

Colorectal cancer (CRC) is one the leading causes of cancer related deaths among Iranians. Despite the various progresses in new therapeutic methods, it has still a low rate of survival. This high ratio of mortality is mainly related to the late diagnosis, in which the patients refer for treatment in advanced stages of tumor. MAIN BODY: colorectal cancer progression is largely associated with molecular and genetic bases. Although Iran has a high ratio of CRC mortality, there is not an efficient genetic panel for detection and prognosis. Therefore, it is critical to introduce new diagnostic markers with ability to detect in early stages.

CONCLUSION

Present review summarizes all of the genetic and epigenetic factors which are reported in CRC until now among the Iranian patients to pave the way of incorporation of new ethnic specific markers into the clinical practice and development of new targeted therapeutic methods.

Knockdown of sal-like 4 expression by small interfering RNA induces apoptosis in breast cancer cells

Breast cancer is the most prevalent cancers worldwide and causes a significant amount of deaths annually. Spalt-like transcription factor 4 is known as a transcription factor, which has an important role in the proliferation of cancerous cells. Small interfering RNA (siRNA) is a short-chain molecule of 20 to 25 nucleotides that protrude on two sides of the 3', two nucleotides. In this study, using a specific sequence of siRNA against the sequence of this gene, its activity is investigated in the cell line of breast cancer. The breast cancer cells (MCF-7) were cultured and then, using a specific anti-sal-like 4 (SALL4) siRNA, their toxic doses were determined. Then, the gene is transfected into the cell. Proliferation and expression of the SALL4 and BCL-2 gene were measured using the real-time polymerase chain reaction method. The specific concentration of siRNA IC₅₀ of the SALL4 gene was 40.35 nmole. Gene expression results indicated that the expression of the Bcl-2 gene in the siRNA group was significantly reduced ( P < 0.05). SiRNA can increase the apoptosis of breast cancer cells by reducing the gene expression of SALL4 gene and Bcl-2; it can be used as a novel targeted therapy. This strategy, in addition to increasing the specificity of the drug, also reduces the side effects when compared with conventional chemotherapy.

Correlation between SALL4 stemness marker and bone morphogenetic protein signaling genes in esophageal squamous cell carcinoma

SALL4, as a stemness marker, plays a key role in the maintenance of pluripotency and self-renewal of cancer stem cells. To elucidate probable linkage between SALL4 stemness marker and bone morphogenetic protein (BMP) cell signaling pathway, we aimed to analyze the expression levels of the related genes in esophageal squamous cell carcinoma (ESCC) patients. Tumoral and corresponding margin normal tissues from 50 treatment-naive ESCC patients were subjected for expression analysis using relative comparative real-time reverse transcription polymerase chain reaction. There were significant correlations between SALL4 mRNA and BMP signaling target genes expression including SIZN1, VENTX, and DIDO1 (P < 0.01). Tight associations of gene expression were observed in primary stages of tumor progression (stages I/II), and the invaded tumors to the adventitia (T3/T4). Furthermore, significant correlations between the expression of BMP signaling target genes were observed (P < 0.01). SALL4 may play role in tumorigenesis and tumor cell invasiveness of ESCC through correlation with BMP signaling genes.

Targeting cancer addiction for SALL4 by shifting its transcriptome with a pharmacologic peptide

Sal-like 4 (SALL4) is a nuclear factor central to the maintenance of stem cell pluripotency and is a key component in hepatocellular carcinoma, a malignancy with no effective treatment. In cancer cells, SALL4 associates with nucleosome remodeling deacetylase (NuRD) to silence tumor-suppressor genes, such as PTEN. Here, we determined the crystal structure of an amino-terminal peptide of SALL4(1-12) complexed to RBBp4, the chaperone subunit of NuRD, at 2.7 Å, and subsequent design of a potent therapeutic SALL4 peptide (FFW) capable of antagonizing the SALL4-NURD interaction using systematic truncation and amino acid substitution studies. FFW peptide disruption of the SALL4-NuRD complex resulted in unidirectional up-regulation of transcripts, turning SALL4 from a dual transcription repressor-activator mode to singular transcription activator mode. We demonstrate that FFW has a target affinity of 23 nM, and displays significant antitumor effects, inhibiting tumor growth by 85% in xenograft mouse models. Using transcriptome and survival analysis, we discovered that the peptide inhibits the transcription-repressor function of SALL4 and causes massive up-regulation of transcripts that are beneficial to patient survival. This study supports the SALL4-NuRD complex as a drug target and FFW as a viable drug candidate, showcasing an effective strategy to accurately target oncogenes previously considered undruggable.

Systematic review of blood diagnostic markers in colorectal cancer

The purpose of this systematic review was to compare the diagnostic ability of blood markers for colorectal cancer (CRC). A systematic review of the literature for diagnostic blood markers for primary human colorectal cancer over the last 5 years was performed. The primary outcome was to assess the diagnostic ability of these markers in diagnosing colorectal cancer. The secondary outcome was to see whether the marker was compared to other markers. The tertiary outcome was to assess diagnostic ability in early versus late CRC, including stage IV disease. We identified 51 studies (29 prospective, 14 retrospective, and 8 meta-analyses). The markers were divided in broadly four groups: nucleic acids (RNA/DNA/messenger RNA/microRNAs), cytokines, antibodies, and proteins. The most promising circulating markers identified among the nucleid acids were NEAT_v2 non-coding RNA, SDC2 methylated DNA, and SEPT9 methylated DNA. The most promising cytokine to detect CRC was interleukin 8, and the most promising circulating proteins were CA11-19 glycoprotein and DC-SIGN/DC-SIGNR. Sensitivities of these markers for detecting primary colorectal carcinoma ranged from 70 to 98% and specificities from 84 to 98.7%. The best studied blood marker was SEPT9 methylated DNA, which showed great variability with sensitivities ranging from 48.2 to 95.6% and specificities from 80 to 98.9%, making its clinical applicability challenging. If combined with fecal immunochemical test (FIT), the sensitivity improved from 78 to 94% in detecting CRC. Methylated SEPT9, methylated SDC2, and -SIGN/DC-SIGNR protein had better sensitivity and specificity than CEA or CA 19-9. With the exception of SEPT9 which is currently being implemented as a screening test for CRC all other markers lacked reproducibility and standardization and were studied in relatively small population samples.

miR-16 targets SALL4 to repress the proliferation and migration of gastric cancer

There is increasing evidence that microRNAs (miRNAs) play important roles in tumor progression and development by targeting different genes, including gastric cancer (GC). However, the role of miR-16 in GC is so far unclear. Herein, we examined the function and potential mechanism of miR-16 in GC. Reverse transcription-quantitative PCR found that miR-16 expression was prominently lower in GC tissues while SALL4 expression was frequently higher than normal tissues. Re-expression of miR-16 could suppress GC cell proliferation and migration by MTT and Transwell assay. We confirmed that miR-16 directly targeted SALL4 in regulating GC by luciferase assay. Knockdown of SALL4 inhibited cell proliferation and migration. Furthermore, SALL4 could counteract the inhibition-effect of miR-16 in GC. In conclusion, for the the first time we demonstrated that miR-16 played inhibitory effect through targeting SALL4 in GC cell proliferation and migration. Our study revealed that miR-16/SALL4 axis was critical in regulating the GC development, indicating a new prospect to regulate GC cell progression and development.

Spalt-like transcription factor 4 as a potential diagnostic and prognostic marker of colorectal cancer

OBJECTIVE

The study aimed to investigate the role of spalt-like transcription factor 4 (SALL4) in the diagnosis and prognosis of colorectal cancer (CRC).

METHODS

Between May 2008 and January 2010, 135 patients with CRC were recruited and subsequently assigned into the case group of the study. Additionally, 140 healthy individuals under identical conditions were selected as the control group. Venous blood was collected from all subjects. High expression of SALL4 was detected by immunohistochemistry, and SALL4 serum levels were detected using ELISA. A 5-year follow-up was conducted. A Kaplan-Meier curve was applied for analysis of survival rates, and a log-rank was used for univariate analysis.

RESULTS

The case group exhibited largely positive expression levels of SALL4. Levels of SALL4 serum were much higher than those in the control group. The AUC value of CRC detected by serum SALL4 was 0.916 (95% CI was 0.881-0.951), which regarded 0.1255 μcg/l to be the point of critical value. This result was in direct relation to data from the receiver operating characteristic curve (ROC). The sensitivity and specificity of serum SALL4 levels in the diagnosis of CRC were 85.9% and 85.7%, respectively. The AUC value of CRC detected by tissue SALL4 was 0.727 (95% CI was 0.666-0.789), 0.5 was regarded as the critical value. The sensitivity and specificity of SALL4 expression in CRC tissues regarding the diagnosis of CRC was determined to be 58.6% and 86.9% respectively. The levels of SALL4 expression in serum and tissues highlighted a correlation to lymph node metastasis (LNM), differentiation degree, Dukes staging and tumor node metastasis staging. Lower serum SALL4 levels were associated with higher survival rates in CRC patients. In accordance with a COX regression, LNM, differentiation degree and SALL4 levels were determined as being prognostic factors in patients with CRC (both P< 0.05).

CONCLUSION

Our experimental data indicated that over expression of SALL4 was found in CRC and low expression of SALL4 was connected with high survival rate after surgery. Thus our study suggested that SALL4 could serve as a potential diagnostic and prognostic marker of CRC.

Upregulation of SALL4 by EGFR activation regulates the stemness of CD44-positive lung cancer

The transcriptional factor SALL4, an important stem cell regulator, is expressed in hematopoietic stem cells and various malignancies, but its role in EGFR-mutated NSCLCs has not been studied yet. Here, we report that the expression of Sal-like protein 4 (SALL4), was significantly higher in EGFR mutated lung tumors than in non-tumor tissue. SALL4-high lung cancer patients had poorer prognosis after surgery than SALL4-low patients. The expression of SALL4 could be induced by the activation of EGFR through the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. The knockdown of SALL4 expression could suppress spheroid formation and the expression of lung cancer stem cell marker CD44. More interestingly, the knockdown of SALL4 expression could suppress the migration, invasion, and metastasis of the lung cancer cells and significantly increase the sensitivity of EGFR mutated cells to Erlotinib. These results suggest that SALL4 may be a novel potential therapeutic target for the diagnosis and treatment of lung cancer.

SALL4 oncogene is an immunogenic antigen presented in various HLA-DR contexts

Purpose: To investigate the immunoprevalence of SALL4-derived peptides in healthy volunteers and cancer patients. Experimental Design: A multistep approach including prediction algorithms was used to design in silico SALL4-derived peptides theoretically able to bind on common HLA-DR and HLA-A/B molecules. The presence of T-cell responses after a long term T-cell assay (28 days) against SALL4 was monitored in 14 healthy donors and the presence of T-cell responses after a short term T-cell assay (10 days) was monitored in 67 cancer patients using IFN-γ ELISPOT assay. A T-cell clone specific for the immunoprevalent A18 K-derived peptide was isolated, characterized and used as a tool to characterize the natural processing of A18 K. Results: A SALL4 specific T-cell repertoire was present in healthy donors (8/14) and cancer patients (29/67) after short term T-cell assay. We further identified two immunoprevalant SALL4-derived peptides, R18 A and A18 K, which bind MHC-class II. In parallel, an A18 K specific Th1 clone recognized monocyte derived Dendritic Cell (moDC) loaded with SALL4 containing cell lysate. The level of IFN-γ secreted by specific T-cell clone was greater in presence of moDC loaded with SALL4 containing cell lysate (49.23 ± 14.02%) than with moDC alone (18.03 ± 3.072%) (p = 0.0477) Conclusion: These results show for the first time immunogenicity of SALL4 oncogenic protein-derived peptides, especially A18 K and R18 A peptides and make them potential targets for personalized medicine. Thus, SALL4 possess major characteristics of a tumor antigen.

MAML1 and TWIST1 co-overexpression promote invasion of head and neck squamous cell carcinoma

AIMS

Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide with considerable morbidity and mortality. Invasion and metastasis of HNSCC is a complex process involving multiple molecules and signaling pathways. Twist Family BHLH Transcription Factor 1 (TWIST1) and Mastermind-like 1 (MAML1) are essential in induction of epithelial-mesenchymal transition through direct regulation of implicated molecules in cellular adhesion, migration and invasion. Our aim in this study was to assess the clinical significance of MAML1 and TWIST1 expression in HNSCC, and elucidate the probable correlation between these genes to exhibit their possible associations with progression and metastasis of the disease.

METHODS

The gene expression profile of MAML1 and TWIST1 was assessed in fresh tumoral compared to distant tumor-free tissues of 55 HNSCC patients using quantitative real-time Polymerase chain reaction (PCR).

RESULTS

Significant overexpression of MAML1 and TWIST1 mRNA was observed in 49.1% and 38.2% (P ˂ 0.05) of tumor specimens, respectively. Overexpression of MAML1 was associated with vascular invasion (P = 0.048). Concomitant overexpression of MAML1 and TWIST1 was significantly correlated to each other (P = 0.004). Co-overexpression of the genes was significantly correlated to the various clinicopathological indices of poor prognosis including depth of tumor invasion (P < 0.01), lymphatic invasion and grade of tumor cell differentiation (P < 0.05).

CONCLUSIONS

Significant correlation between MAML1 and TWIST1 in HNSCC was revealed. This study was the first report elucidating MAML1 clinical relevance in HNSCC. These new findings suggest an oncogenic role for concomitant expression of MAML1 and TWIST1 genes in HNSCC invasion and metastasis.

Effect of siRNA-silencing of SALL2 gene on growth, migration and invasion of human ovarian carcinoma A2780 cells

Background

The role of Spalt-like gene-2 (SALL2) in tumorigenesis remains incompletely elucidated. This study investigated the effects of SALL2 on human ovarian carcinoma (OC) A2780 cells and the probable mechanism.

Methods

Expression of SALL2 in human OC cell lines were detected by reverse transcription PCR (RT-PCR) and Western blot analysis. A2780 cells were transfected with small-interfering ribonucleic acid (siRNA) to silence SALL2. SALL2 expression was detected by RT-PCR, Western blot analysis and immunofluorescence assay. Cell proliferation was measured by CCK-8 assay and flow cytometry (FCM). Apoptosis was measured by FCM. Cell migration was detected by real-time cell analysis. Cell invasion was detected by transwell assay. mRNA expression of p21 was detected by quantitative real-time PCR. Western blot analysis was used to determine the expression of matrix metalloproteinase (MMP)2, MMP9, protein kinase B (PKB, also called Akt), and phosphorylated-Akt (p-Akt).

Results

SALL2 was expressed in six OC cell lines, and the expression was the highest in A2780 cells. Compared with that in the Scramble group, SALL2 expression in A2780 was downregulated after transfection with siRNA-2 and siRNA-3 for 48 h. Compared with that in the Scramble group, proliferation of A2780 cells in the siRNA-2 group increased after transfection for 24, 48 and 72 h. In the siRNA-2 group, the proportion of A2780 cells decreased in the G0/G1 phase, and cell apoptosis decreased after transfection for 48 h. Compared with that in the Scramble group, the cell migration and invasion abilities of A2780 cells increased. Compared with that in the Scramble group, p21 mRNA expression in A2780 cells decreased after transfection with siRNA2. When SALL2 was silenced, the expression of MMP2/9 and p-Akt in A2780 cells increased. Furthermore, the PI3K inhibitor LY294002 could effectively reversed SALL2 siRNA-induced phosphorylation of Akt, migration and invasion of A2780 cells.

Conclusion

Transient silencing of SALL2 promotes cell proliferation, migration, and invasion, and inhibits apoptosis of A2780 cells. In SALL2 siRNA-silenced cells, p21 expression was decreased. SALL2 knockdown by siRNA induces the migration and invasion of A2780 cells; this phenomenon is possibly associated with the increased expression of MMP2/9 and the activation of the PI3K/Akt signalling pathway.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3843-y) contains supplementary material, which is available to authorized users.

Cancer stem cells in colorectal cancer: a review

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men. Adenocarcinoma accounts for 90% of CRC cases. There has been accumulating evidence in support of the cancer stem cell (CSC) concept of cancer which proposes that CSCs are central in the initiation of cancer. CSCs have been the focus of study in a range of cancers, including CRC. This has led to the identification and understanding of genes involved in the induction and maintenance of pluripotency of stem cells, and markers for CSCs, including those investigated specifically in CRC. Knowledge of the expression pattern of CSCs in CRC has been increasing in recent years, revealing a heterogeneous population of cells within CRC ranging from pluripotent to differentiated cells, with overlapping and sometimes unique combinations of markers. This review summarises current literature on the understanding of CSCs in CRC, including evidence of the presence of CSC subpopulations, and the stem cell markers currently used to identify and localise these CSC subpopulations. Future research into this field may lead to improved methods for early detection of CRC, novel therapy and monitoring of treatment for CRC and other cancer types.

Coexpression of SALL4 with HDAC1 and/or HDAC2 is associated with underexpression of PTEN and poor prognosis in patients with hepatocellular carcinoma

Spalt-like transcriptional factor 4 (SALL4), a stem marker, is reactivated in several cancers. A previous study has demonstrated that SALL4 interacts with the nucleosome remodeling deacetylase complex, which contains histone deacetylase 1 (HDAC1) and histone deacetylase 2 (HDAC2). In this study, we investigated the expression status of SALL4, HDAC1, and HDAC2 and their relationship with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) by immunohistochemical analysis of the posthepatectomy specimens of 135 patients with hepatocellular carcinoma who were treated at our hospital. Ninety-two frozen samples were subjected to quantitative reverse-transcription polymerase chain reaction analysis to detect the messenger RNA levels of PTEN. Seventy-six (56%) of 135 patients were positive for SALL4, and this group had a higher prevalence of hepatitis B antigen, a higher value of α-fetoprotein (AFP) and protein induced by vitamin K absence (PIVKAII) and poor histologic differentiation. The 5-year survival rate was significantly lower in the SALL4-positive group. High HDAC1 expression (51%) was correlated with a poor histologic differentiation and a poor prognosis. High HDAC2 expression (46%) was associated with a higher prevalence of hepatitis B antigen positivity, a poor histologic differentiation and higher prevalence of vascular invasion, and a lower 5-year survival rate. Coexpression of SALL4 with HDAC1 and/or HDAC2 was correlated with underexpression of PTEN. Moreover, multivariable analysis revealed that coexpression of SALL4 with HDAC1 and/or HDAC2 was predictive of an unfavorable prognosis. Our data thus suggested that the combination of SALL4, HDAC1, and HDAC2 may provide a potential target for molecular therapy.

TWIST1 upregulates the MAGEA4 oncogene

Overexpression of MAGEA4 oncogene has been demonstrated in different malignancies; however, little is known about its exact mechanism for overexpression. TWIST1, as a bHLH transcription factor, activates a cell migration‐invasion program involved in both embryonic and tumor development. Since MAGEA4 overexpression was statistically correlated to TWIST1, we aimed to elucidate the probable regulatory role of TWIST1 on MAGEA4 expression in KYSE30 cells. Methods: Expression pattern of MAGEA4 and TWIST1 was analyzed in 55 ESCC patients using relative comparative real‐time PCR. In silico analysis of the MAGEA4 gene was performed. Methylation status of MAGEA4 promoter was determined by quantitative methylation specific PCR (qMSP). Using a retroviral system, KYSE30 cells were transduced to ectopically express TWIST1, followed by qRT‐PCR, Western blot analysis, chromatin immunoprecipitation (ChIP), and luciferase assays to elucidate the regulatory role of TWIST1 on MAGEA4 gene expression. Results: Concomitant overexpression of MAGEA4 and TWIST1 was detected in ESCC in significant correlation with each other in different clinicopathological indices of poor prognosis (P < 0.05). The TWIST1‐expressing cells showed significantly higher MAGEA4 expression compared to control cells. ChIP and luciferase assays results confirmed indirect binding of TWIST1 to the E‐boxes of MAGEA4 promoter sequence and revealed a novel regulatory role of TWIST1 in MAGEA4 upregulation. Conclusion: Since MAGEA4 is a highly expressed oncogene in a variety of malignancies in significant correlation with tumor cell invasiveness and aggressiveness, our finding may help understand one regulatory mechanism of increased expression in tumor cells. © 2016 Wiley Periodicals, Inc.

Negative Regulatory Role of TWIST1 on SNAIL Gene Expression

Epithelial-mesenchymal transition (EMT) is crucial for specific morphogenetic movements during embryonic development as well as pathological processes of tumor cell invasion and metastasis. TWIST and SNAIL play vital roles in both developmental and pathological EMT. Our aim in this study was to investigate the functional correlation between TWIST1 and SNAIL in human ESCC cell line (KYSE-30). The packaging cell line GP293T was cotransfected with either control retroviral pruf-IRES-GFP plasmid or pruf-IRES-GFP-hTWIST1 and pGP plasmid. The KYSE-30 ESCC cells were transduced with produced viral particles and examined with inverted fluorescence microscope. DNA was extracted from transduced KYSE-30 cells and analyzed for copy number of integrated retroviral sequences in the target cell genome. The concentration of retroviral particles was determined by Real-time PCR. After RNA extraction and cDNA synthesis, the mRNA expression of TWIST1 and SNAIL was assessed by comparative real-time PCR amplification. Ectopic expression of TWIST1 in KYSE-30, dramatically reduces SNAIL expression. Retroviral transduction enforced TWIST1 overexpression in GFP-hTWIST1 nearly 9 folds in comparison with GFP control cells, and interestingly, this TWIST1 enforced expression caused a - 7 fold decrease of SNAIL mRNA expression in GFP-hTWIST1 compared to GFP control cells. Inverse correlation of TWIST1 and SNAIL mRNA levels may introduce novel molecular gene expression pathway controlling EMT process during ESCC aggressiveness and tumorigenesis. Consequently, these data extend the spectrum of biological activities of TWIST1 and propose that therapeutic repression of TWIST1 may be an effective strategy to inhibit cancer cell invasion and metastasis.

Crosstalk between SHH and stemness state signaling pathways in esophageal squamous cell carcinoma

The expression of GLI1 as a downstream gene of sonic hedgehog (Hh) pathway, studied in a variety of cancers including esophageal squamous cell carcinoma (ESCC). However, the interaction of Hh with other developmental pathways needs to be elucidated. In this study, we aimed to investigate the correlation of GLI1 expression with transcription factors (TFs) of stem cell signaling pathways, and their association with clinico-pathological data of ESCC. Using real-time PCR, we assessed the expression of GLI1 mRNA in 49 ESCC patients, and analyzed the correlation between GLI1 and selected TFs. The results showed overexpression of GLI1 in ESCC tissues in significant correlation with lymph node metastasis. The GLI1 up-regulation was also correlated to the SOX2 and SIZN1 (Smad-interacting zinc finger protein) expression. These correlations may confirmed the role of GLI1 in crosstalk among different cell signaling pathways in ESCC. To our knowledge, this is the first study to demonstrate the correlation of GLI1 expression with stemness marker and BMP signaling in ESCC.

SALL4 promotes gastric cancer progression through activating CD44 expression

The stem cell factor SALL4 (Sal-like protein 4) plays important roles in the development and progression of cancer. SALL4 is critically involved in tumour growth, metastasis and therapy resistance. However, the underlying mechanisms responsible for the oncogenic roles of SALL4 have not been well characterized. In this study, we demonstrated that SALL4 knockdown by short hairpin RNA greatly inhibited the proliferation, migration and invasion of gastric cancer cells. We further confirmed the inhibitory effects of SALL4 knockdown on gastric cancer cells by using a tetracycline-inducible system. Mechanistically, SALL4 knockdown downregulated the expression of CD44. The results of luciferase assay and chromatin immunoprecipitation study showed that SALL4 bound to CD44 promoter region and transcriptionally activated CD44. The results of rescue study revealed that CD44 overexpression antagonized SALL4 knockdown-mediated inhibition of gastric cancer cell proliferation, migration, and invasion in vitro and gastric cancer growth in vivo. Collectively, our findings indicate that SALL4 promotes gastric cancer progression through directly activating CD44 expression, which suggests a novel mechanism for the oncogenic roles of SALL4 in gastric cancer and represents a new target for gastric cancer therapy.

MicroRNA-16 inhibits the proliferation, migration and invasion of glioma cells by targeting Sal-like protein 4

MicroRNAs (miRNAs or miRs), a class of non-coding RNAs 18-25 nucleotides in length, act as key regulators in the development and malignant progression of various human cancers by modulating the expression of their target genes. Recently, miR‑16 has been demonstrated to be play a role in glioma. However, the regulatory mechanisms of miR‑16 in glioma growth and metastasis remain largely unclear. In the present study, qRT-PCR revealed that miR‑16 was significantly downregulated in 23 glioma tissue specimens compared to 7 normal brain tissue specimens. Moreover, its levels were markedly lower in the glioma samples at stages T2-T4 compared to those at stage T1. The overexpression of miR-16 significantly suppressed the proliferation, migration and invasion of U251 and U87 glioma cells. Luciferase reporter assay identified Sal-like protein 4 (SALL4) as a target gene of miR‑16, and its protein levels were found to be decreased in miR‑16-overexpressing U251 and U87 cells. Furthermore, the overexpression of SALL4 significantly reversed the suppressive effects of miR‑16 on the proliferation, migration and invasion of U251 and U87 cells, suggesting that miR‑16 playsa tumor suppressor role in glioma by inhibiting cell proliferation and invasion through the targeting of SALL4. Finally, we found that SALL4 was significantly upregulated in glioma tissues compared to normal brain tissues, and its levels were markedly higher in the glioma tissues at stages T2-T4 compared to those at stage T1. In addition, the expression levels of SALL4 inversely correlated with the miR‑16 levels in glioma tissues, suggesting that the downregulation of miR‑16 contributes to the upregulation of SALL4 in glioma. On the whole, the findings of this study indicate a role for the miR‑16/SALL4 axis in glioma. Our data may also provide a potential therapeutic target for the treatment of glioma.

Complementary Glycomic Analyses of Sera Derived from Colorectal Cancer Patients by MALDI-TOF-MS and Microchip Electrophoresis

Colorectal cancer is the fourth most prevalent cancer in the United States, yet there are no reliable noninvasive early screening methods available. Serum-based glycomic profiling has the necessary sensitivity and specificity to distinguish disease states and provide diagnostic potential for this deadly form of cancer. We applied microchip electrophoresis and MALDI-TOF-MS-based glycomic procedures to 20 control serum samples and 42 samples provided by patients diagnosed with colorectal cancer. Within the identified glycans, the position of fucose units was located to quantitate possible changes of fucosyl isomeric species associated with the pathological condition. MALDI-MS data revealed several fucosylated tri- and tetra-antennary glycans which were significantly elevated in their abundance levels in the cancer samples and distinguished the control samples from the colorectal cancer cohort in the comprehensive profiles. When compared to other cancers studied previously, some unique changes appear to be associated with colorectal cancer, being primarily associated with fucosyl isomers. Through MS and microchip electrophoresis-based glycomic methods, several potential biomarkers were identified to aid in the diagnosis and differentiation of colorectal cancer. With its unique capability to resolve isomers, microchip electrophoresis can yield complementary analytical information to MS-based profiling.

The expression of SALL4 is significantly associated with EGFR, but not KRAS or EML4-ALK mutations in lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide; unfortunately, its prognosis is still very poor. Therefore, developing the target molecular is very important for lung cancer diagnosis and treatment, especially in the early stage. With this in view, spalt-like transcription factor 4 (SALL4) is considered a potential biomarker for diagnosis and prognosis in cancers, including lung cancer.

METHODS

In order to better investigate the association between the expression of SALL4 and driver genes mutation, 450 histopathologically diagnosed patients with lung cancer and 11 non-cancer patients were enrolled to test the expression of SALL4 and the status of driver genes mutation. This investigation included epidermal growth factor receptor (EGFR), kirsten rat sarcoma viral oncogene homolog (KRAS), and a fusion gene of the echinoderm microtubule-associated protein-like 4 (EML4) and the anaplastic lymphoma kinase (ALK).

RESULTS

The results of the study showed that females harbored more EGFR mutation in adenocarcinoma (ADC). The mutation rate of KRAS and EML4-ALK was about 5%, and the double mutations of EGFR/EML4-ALK were higher than EGFR/KRAS. In the expression analysis, the expression of SALL4 was much higher in cancer tissues than normally expected, especially in tissues that carried EGFR mutation (P<0.05), however, there were no significant differences between different mutation types. Likewise, there were no significant differences between expression of SALL4 and KRAS and EML4-ALK mutations.

CONCLUSIONS

SALL4 is up regulated in lung cancer specimens and harbors EGFR mutation; this finding indicates that SALL4 expression may be relevant with EGFR, which could provide a new insight to lung cancer therapy. The mechanism needs further investigation and analysis.