Association of High Expression Levels of SOX2, NANOG, and OCT4 in Gastric Cancer Tumor Tissues with Progression and Poor Prognosis

Dickopff 1 inhibits cancer stem cell properties and promotes neuronal differentiation of human neuroblastoma cell line SH-SY5Y

Neuroblastomas are pediatric tumors arising from undifferentiated cells of neural crest origin with stem cell-like characteristics. Dysregulation of Wnt/β-catenin signaling has been shown to be linked to the development of various tumors. Activated Wnt signaling results in β-catenin accumulation in the nucleus to support pro-neoplastic traits. DKK1, a secreted glycoprotein, is an inhibitor of Wnt signaling, and the addition of DKKI to the culture medium has been used to suppress the Wnt pathway. This study aimed to analyze the role of Dickopff-1 as a potential differentiating agent for the neuroblastoma cell line SH-SY5Y and neurospheres derived from it. The treatment of SH-5Y5Y derived neurospheres by DKK1 resulted in their disintegration and reduced proliferation markers like Ki67, PCNA. DKK1 treatment to the neurospheres also resulted in the loss of cancer stem cell markers like CD133, KIT and pluripotency markers like SOX2, OCT4, NANOG. DKK1 treatment caused reduction in mRNA expression of β-catenin and TCF genes like TCF4, TCF12. When the SH-SY5Y cancer cells were grown under differentiating conditions, DKKI caused neuronal differentiation by itself, and in synergy with retinoic acid. This was verified by the expression of markers like MAPT, DCX, GAP43, ENO2 and also with changes in neurite length. We concluded that Wnt inhibition, as exemplified by DKK1 treatment, is therefore a possible differentiating condition and also suppresses the proliferative and cancer stemness related properties of SH-SY5Y neuroblastoma cells.

LncRNA BASP1-AS1 is a positive regulator of stemness and pluripotency in human SH-SY5Y neuroblastoma cells

Neuroblastoma is the most common extra-cranial solid tumor diagnosed mostly in children below the age of five years and comprises of about 15 % of all paediatric cancer deaths. Tumor initiating cancer stem cells (CSCs) can be targeted for better treatment approaches. BASP1-AS1 is a long non coding (Lnc) RNA that is a divergent LncRNA for its coding gene brain abundant membrane attached signal protein 1 (BASP1). We had earlier demonstrated it to be expressed in foetus derived human neural progenitor cells (hNPCs), where it was a positive regulator of BASP1 and was critical for neural differentiation. In this study, we have investigated the role of BASP1-AS1 in CSCs derived from the human neuroblastoma cell line SH-SY5Y. We cultured SH-SY5Y cells on Poly-d-Lysine coated flasks in serum free media supplemented with growth factors, which led to the enrichment of CSCs as determined by marker expression. When grown on ultra-low attachment flasks, these cells formed CSCs enriched neurospheres. We examined the effects of BASP1-AS1 siRNA mediated knockdown on CSCs enriched SH-SY5Y cells and SH-SY5Y derived neurospheres. BASP1-AS1 knockdown decreased the levels of the corresponding gene BASP1 and the rate of cell proliferation of CSCs enriched cells along with low expression of Ki67. It also reduced the mRNA levels of stem cell and pluripotency gene markers (CD133, CD44, c-KIT, SOX2, OCT4 and NANOG), as also Wnt 2 and the Wnt pathway effector β catenin. It also abrogated the formation of neurospheres in ultra-low attachment flasks. A similar effect on proliferation and stemness related properties was seen on BASP1 knockdown. BASP1-AS1 and its related pathways may provide a point of intervention for the CSCs population in neuroblastoma.

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.

Cancer-associated fibroblasts-secreted exosomal miR-92a-3p promotes tumor growth and stemness in hepatocellular carcinoma through activation of Wnt/β-catenin signaling pathway by suppressing AXIN1

Cancer-associated fibroblasts (CAFs) are a major cellular component in the tumor microenvironment and have been shown to exhibit protumorigenic effects in hepatocellular carcinoma (HCC). This study aimed to delve into the mechanisms underlying the tumor-promoting effects of CAFs in HCC. Small RNA sequencing was conducted to screen differential expressed microRNAs in exosomes derived from CAFs and normal fibroblasts (NFs). The miR-92a-3p expression was then measured using reverse transcriptase quantitative real-time PCR in CAFs, NFs, CAFs-derived exosomes (CAFs-Exo), and NF-derived exosomes (NFs-Exo). Compared to NFs or NF-Exo, CAFs and CAFs-Exo significantly promoted HCC cell proliferation, migration, and stemness. Additionally, compared to NFs or NF-Exo, miR-92a-3p level was notably higher in CAFs and CAFs-Exo, respectively. Exosomal miR-92a-3p was found to enhance HCC cell proliferation, migration, and stemness. Meanwhile, AXIN1 was targeted by miR-92a-3p. Exosomal miR-92a-3p could activate β-catenin/CD44 signaling in HCC cells by inhibiting AXIN1 messenger RNA. Furthermore, in vivo studies verified that exosomal miR-92a-3p notably promoted tumor growth and stemness through targeting AXIN1/β-catenin axis. Collectively, CAFs secreted exosomal miR-92a-3p was capable of promoting growth and stemness in HCC through activation of Wnt/β-catenin signaling pathway by suppressing AXIN1. Therefore, targeting CAFs-derived miR-92a-3p may be a potential strategy for treating HCC.

Polyhedral magnetic nanoparticles induce apoptosis in gastric cancer stem cells and suppressing tumor growth through magnetic force generation

Gastric cancer is a prevalent malignant tumor worldwide, posing challenges due to its poor prognosis and limited treatment options. Cancer stem cells (CSCs) were demonstrated as a subset of cancer cells responsible for tumor initiation and progression, and their inherent resistance to conventional chemotherapy and radiotherapy critically contributes to tumor recurrence and metastasis. Promoting the eradication of cancer stem cells is crucial for enhancing the efficacy of cancer treatments. This study introduces a novel therapeutic strategy utilizing polyhedral magnetic nanoparticles (PMNPs) functionalized with CD44 antibodies and cell-penetrating peptides (CPPs) to improve uptake by gastric cancer stem cells (MCSCs). PMNPs, synthesized via thermal decomposition, exhibited a diameter of 90 nm ± 9 nm and a saturation magnetization of 79.9 emu/g. Functionalization enhanced their uptake capabilities. Under a rotating magnetic field (RMF) of 15 Hz, PMNPs disrupted cellular structure, leading to apoptosis and ferroptosis in MCSCs. The in vitro studies showed significant reduction in MCSCs viability, while in vivo studies demonstrated tumor growth suppression with minimal side effects and high biocompatibility. This work presents a novel strategy for designing magnetic nanoparticles to mechanically destroy cancer stem cells, offering a more efficient and safety treatment option for gastric cancer.

Dissecting SOX2 expression and function reveals an association with multiple signaling pathways during embryonic development and in cancer progression

SRY (Sex Determining Region) box 2 (SOX2) is an essential transcription factor that plays crucial roles in activating genes involved in pre- and post-embryonic development, adult tissue homeostasis, and lineage specifications. SOX2 maintains the self-renewal property of stem cells and is involved in the generation of induced pluripotency stem cells. SOX2 protein contains a particular high-mobility group domain that enables SOX2 to achieve the capacity to participate in a broad variety of functions. The information about the involvement of SOX2 with gene regulatory elements, signaling networks, and microRNA is gradually emerging, and the higher expression of SOX2 is functionally relevant to various cancer types. SOX2 facilitates the oncogenic phenotype via cellular proliferation and enhancement of invasive tumor properties. Evidence are accumulating in favor of three dimensional (higher order) folding of chromatin and epigenetic control of the SOX2 gene by chromatin modifications, which implies that the expression level of SOX2 can be modulated by epigenetic regulatory mechanisms, specifically, via DNA methylation and histone H3 modification. In view of this, and to focus further insights into the roles SOX2 plays in physiological functions, involvement of SOX2 during development, precisely, the advances of our knowledge in pre- and post-embryonic development, and interactions of SOX2 in this scenario with various signaling pathways in tumor development and cancer progression, its potential as a therapeutic target against many cancers are summarized and discussed in this article.

Integrated analysis of the role of PR/SET domain 14 in gastric cancer

BACKGROUND

Gastric cancer is one of the most common tumors worldwide, and most patients are deprived of treatment options when diagnosed at advanced stages. PRDM14 has carcinogenic potential in breast and non-small cell lung cancer. however, its role in gastric cancer has not been elucidated.

METHODS

We aimed to elucidate the expression of PRDM14 using pan-cancer analysis. We monitored the expression of PRDM14 in cells and patients using quantitative polymerase chain reaction, western blotting, and immunohistochemistry. We observed that cell phenotypes and regulatory genes were influenced by PRDM14 by silencing PRDM14. We evaluated and validated the value of the PRDM14-derived prognostic model. Finally, we predicted the relationship between PRDM14 and small-molecule drug responses using the Connectivity Map and The Genomics of Drug Sensitivity in Cancer databases.

RESULTS

PRDM14 was significantly overexpressed in gastric cancer, which identified in cell lines and patients' tissues. Silencing the expression of PRDM14 resulted in apoptosis promotion, cell cycle arrest, and inhibition of the growth and migration of GC cells. Functional analysis revealed that PRDM14 acts in epigenetic regulation and modulates multiple DNA methyltransferases or transcription factors. The PRDM14-derived differentially expressed gene prognostic model was validated to reliably predict the patient prognosis. Nomograms (age, sex, and PRDM14-risk score) were used to quantify the probability of survival. PRDM14 was positively correlated with sensitivity to small-molecule drugs such as TPCA-1, PF-56,227, mirin, and linsitinib.

CONCLUSIONS

Collectively, our findings suggest that PRDM14 is a positive regulator of gastric cancer progression. Therefore, it may be a potential therapeutic target for gastric cancer.

Exploiting transcription factors to target EMT and cancer stem cells for tumor modulation and therapy

Transcription factors (TFs) are essential in controlling gene regulatory networks that determine cellular fate during embryogenesis and tumor development. TFs are the major players in promoting cancer stemness by regulating the function of cancer stem cells (CSCs). Understanding how TFs interact with their downstream targets for determining cell fate during embryogenesis and tumor development is a critical area of research. CSCs are increasingly recognized for their significance in tumorigenesis and patient prognosis, as they play a significant role in cancer initiation, progression, metastasis, and treatment resistance. However, traditional therapies have limited effectiveness in eliminating this subset of cells, allowing CSCs to persist and potentially form secondary tumors. Recent studies have revealed that cancer cells and tumors with CSC-like features also exhibit genes related to the epithelial-to-mesenchymal transition (EMT). EMT-associated transcription factors (EMT-TFs) like TWIST and Snail/Slug can upregulate EMT-related genes and reprogram cancer cells into a stem-like phenotype. Importantly, the regulation of EMT-TFs, particularly through post-translational modifications (PTMs), plays a significant role in cancer metastasis and the acquisition of stem cell-like features. PTMs, including phosphorylation, ubiquitination, and SUMOylation, can alter the stability, localization, and activity of EMT-TFs, thereby modulating their ability to drive EMT and stemness properties in cancer cells. Although targeting EMT-TFs holds potential in tackling CSCs, current pharmacological approaches to do so directly are unavailable. Therefore, this review aims to explore the role of EMT- and CSC-TFs, their connection and impact in cellular development and cancer, emphasizing the potential of TF networks as targets for therapeutic intervention.

Generation of 3D melanoma models using an assembloid-based approach

While 3D tumor models have greatly evolved over the past years, there is still a strong requirement for more biosimilar models which are capable of recapitulating cellular crosstalk within the tumor microenvironment while equally displaying representative levels of tumor aggressiveness and invasion. Herein, we disclose an assembloid melanoma model based on the fusion of individual stromal multicellular spheroids (MCSs). In contrast to more traditional tumor models, we show that it is possible to develop self-organizing, heterotypic melanoma models where tumor cells present stem-cell like features like up-regulated pluripotency master regulators SOX2, POU5F1 and NANOG. Additionally, these assembloids display high levels of invasiveness while embedded in 3D matrices as evidenced by stromal cell promotion of melanoma cell invasion via metalloproteinase production. Furthermore, sensitivity to anticancer drug doxorubicin was demonstrated for the melanoma assembloid model. These findings suggest that melanoma assembloids may play a significant role in the field of 3D cancer models as they more closely mimic the tumor microenvironment when compared to more traditional MCSs, opening the doors to a better understanding of the role of tumor microenvironment in supporting tumor progression. STATEMENT OF SIGNIFICANCE: The development of complex 3D tumor models that better recapitulate the tumor microenvironment is crucial for both an improved comprehension of intercellular crosstalk and for more efficient drug screening. We have herein developed a self-organizing heterotypic assembloid-based melanoma model capable of closely mimicking the tumor microenvironment. Key features recapitulated were the preservation of cancer cell stemness, sensitivity to anti-cancer agents and tumor cell invasion promoted by stromal cells. The approach of pre-establishing distinct stromal domains for subsequent combination into more complex tumor constructs provides a route for developing superior tumor models with a higher degree of similarity to native cancer tissues.

Elevation of LEM Domain Containing 1 Predicts Poor Prognosis of NSCLC Patients and Triggers Malignant Stemness and Invasion of NSCLC Cells by Stimulating PI3K/AKT Pathway

BACKGROUND

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death globally. LEM domain containing 1 (LEMD1) function has been identified in several cancers but not in NSCLC.

OBJECTIVE

This study aimed to investigate the LEMD1 function in NSCLC.

METHODS

NSCLC tissues were obtained from 66 patients, and LEMD1 expressions were measured using quantitative real-time PCR, immunohistochemical assay, and Western blot. Overall survival of NSCLC patients was estimated by the Kaplan-Meier method. Meanwhile, LEMD1 function and mechanism were assessed using Cell Counting Kit-8, 5-Ethynyl-2'-deoxyuridine analysis, Transwell, Sphere formation assay, and flow cytometry. Furthermore, LEMD1 function in vivo was evaluated by establishing a xenograft tumor model, hematoxylin-eosin staining, and immunohistochemical assay.

RESULTS

LEMD1 was highly expressed in NSCLC tissues and was interrelated to tumor differentiation, TNM stage, and lymph node metastasis of patients. Overall survival of NSCLC patients with high LEMD1 was found to be lower than that of patients with low LEMD1. Functionally, interference with LEMD1 restrained NSCLC cell proliferation, invasion, and stemness characteristics. Mechanistically, LEMD1 facilitated the malignant phenotype of NSCLC, and 740 Y-P reversed this impact, prompting that LEMD1 aggravated NSCLC by activating PI3K/AKT pathway. Furthermore, LEMD1 knockdown hindered NSCLC proliferation in vivo. Conclusion: LEMD1 accelerated NSCLC cell proliferation, invasion, and stemness characteristics via activating PI3K/AKT pathway.

High OCT4 Expression Might Be Associated with an Aggressive Phenotype in Rectal Cancer

Rectal cancer (RC) is one of the most common malignant neoplasms, and cancer stem cells (CSCs) of the intestinal tract have been implicated in its origin. The oncofetal protein OCT4 has been linked to neoplastic processes, but its role and clinical significance in RC are unknown. This study investigates the expression of the stem cell marker OCT4 related to clinical-pathological characteristics and its clinical significance in RC patients. The expression level of stem cell marker OCT4 was analyzed in 22 primary rectal tumors by western blot. The association between OCT4 protein expression and the clinical-pathological features of tumors was evaluated by χ² test and Fisher's exact test. We demonstrated that the expression of the stem cell marker OCT4 was observed in tumor tissue but not adjacent non-tumor tissue. High expression of the stem cell marker OCT4 was significantly associated with histological differentiation grade (p = 0.039), tumor invasion level (p = 0.004), lymph node involvement (p = 0.044), tumor-node-metastasis (TNM) stage (p = 0.002), and clinical stage (p = 0.021). These findings suggest that high OCT4 expression is associated with a more aggressive RC phenotype, with a greater likelihood of progression and metastasis. These results shed light on the importance of targeting this CSC marker to attenuate RC progression.

Upregulation of the Oct3/4 Network in Basal Breast Cancer Is Associated with Its Metastatic Potential and Shows Tissue Dependent Variability

Adaptive plasticity of Breast Cancer stem cells (BCSCs) is strongly correlated with cancer progression and resistance, leading to a poor prognosis. In this study, we report the expression profile of several pioneer transcription factors of the Oct3/4 network associated with tumor initiation and metastasis. In the triple negative breast cancer cell line (MDA-MB-231) stably transfected with human Oct3/4-GFP, differentially expressed genes (DEGs) were identified using qPCR and microarray, and the resistance to paclitaxel was assessed using an MTS assay. The tumor-seeding potential in immunocompromised (NOD-SCID) mice and DEGs in the tumors were also assessed along with the intra-tumor (CD44+/CD24-) expression using flow cytometry. Unlike 2-D cultures, the Oct3/4-GFP expression was homogenous and stable in 3-D mammospheres developed from BCSCs. A total of 25 DEGs including Gata6, FoxA2, Sall4, Zic2, H2afJ, Stc1 and Bmi1 were identified in Oct3/4 activated cells coupled with a significantly increased resistance to paclitaxel. In mice, the higher Oct3/4 expression in tumors correlated with enhanced tumorigenic potential and aggressive growth, with metastatic lesions showing a >5-fold upregulation of DEGs compared to orthotopic tumors and variability in different tissues with the highest modulation in the brain. Serially re-implanting tumors in mice as a model of recurrence and metastasis highlighted the sustained upregulation of Sall4, c-Myc, Mmp1, Mmp9 and Dkk1 genes in metastatic lesions with a 2-fold higher expression of stem cell markers (CD44+/CD24-). Thus, Oct3/4 transcriptome may drive the differentiation and maintenance of BCSCs, promoting their tumorigenic potential, metastasis and resistance to drugs such as paclitaxel with tissue-specific heterogeneity.

SOX2-associated signaling pathways regulate biological phenotypes of cancers

SOX2 is a transcription factor involved in multiple stages of embryonic development. In related reports, SOX2 was found to be abnormally expressed in tumor tissues and correlated with clinical features such as TNM staging, tumor grade, and prognosis in patients with various cancer types. In most cancer types, SOX2 is a tumor-promoting factor that regulates tumor progression and metastasis primarily by maintaining the stemness of cancer cells. In addition, SOX2 also regulates the proliferation, apoptosis, invasion, migration, ferroptosis and drug resistance of cancer cells. However, SOX2 acts as a tumor suppressor in some cases in certain cancer types, such as gastric and lung cancer. These key regulatory functions of SOX2 involve complex regulatory networks, including protein-protein and protein-nucleic acid interactions through signaling pathways and noncoding RNA interactions, modulating SOX2 expression may be a potential therapeutic strategy for clinical cancer patients. Therefore, we sorted out the phenotypes related to SOX2 in cancer, hoping to provide a basis for further clinical translation.

Comprehensive Analysis of Gene Expression Profiling to Explore Predictive Markers for Eradication Therapy Efficacy against Helicobacter pylori-Negative Gastric MALT Lymphoma

Although radiotherapy is the standard treatment for Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy using antibiotics and an acid secretion suppressor can sometimes induce complete remission. We explored predictive markers for the response to eradication therapy for gastric MALT lymphoma that were negative for both API2-MALT1 and Hp infection using comprehensive RNA sequence analysis. Among 164 gastric MALT lymphoma patients who underwent eradication therapy as primary treatment, 36 were negative for both the API2-MALT1 fusion gene and Hp infection. Based on eradication therapy efficacy, two groups were established: complete response (CR) and no change (NC). The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that cancer-related genes and infection-related genes were highly expressed in the NC and CR groups, respectively. Based on this finding and transcription factor, gene ontology enrichment, and protein-protein interaction analyses, we selected 16 candidate genes for predicting eradication therapy efficacy. Real-time PCR validation in 36 Hp-negative patients showed significantly higher expression of olfactomedin-4 (OLFM4) and the Nanog homeobox (NANOG) in the CR and NC groups, respectively. OLFM4 and NANOG could be positive and negative predictive markers, respectively, for eradication therapy efficacy against gastric MALT lymphoma that is negative for both API2-MALT1 and Hp infection.

Modulation of Spheroid Forming Capacity and TRAIL Sensitivity by KLF4 and Nanog in Gastric Cancer Cells

The expression of pluripotency factors, and their associations with clinicopathological parameters and drug response have been described in various cancers, including gastric cancer. This study investigated the association of pluripotency factor expression with the clinicopathological characteristics of gastric cancer patients, as well as changes in the expression of these factors upon the stem cell-enriching spheroid culture of gastric cancer cells, regulation of sphere-forming capacity, and response to cisplatin and TRAIL treatments by Nanog and KLF4. Nanog expression was significantly associated with the emergence of a new tumor and a worse prognosis in gastric cancer patients. The expression of the pluripotency factors varied among six gastric cancer cells. KLF4 and Nanog were expressed high in SNU-601, whereas SOX2 was expressed high in SNU-484. The expression of KLF4 and SOX2 was increased upon the spheroid culture of SNU-601 (KLF4/Nanog-high) and SNU-638 (KLF4/Nanog-low). The spheroid culture of them enhanced TRAIL-induced viability reduction, which was accompanied by the upregulation of death receptors, DR4 and DR5. Knockdown and overexpression of Nanog in SNU-601 and SNU-638, respectively, did not affect spheroid-forming capacity, however, its expression was inversely correlated with DR4/DR5 expression and TRAIL sensitivity. In contrast, KLF4 overexpression in SNU-638 increased spheroid formation, susceptibility to cisplatin and TRAIL treatments, and DR4/DR5 expression, while the opposite was found in KLF4-silenced SNU-601. KLF4 is supposed to play a critical role in DR4/DR5 expression and responses to TRAIL and cisplatin, whereas Nanog is only implicated in the former events only. Direct regulation of death receptor expression and TRAIL response by KLF4 and Nanog have not been well documented previously, and the regulatory mechanism behind the process remains to be elucidated.

Dysregulated FOXM1 signaling in the regulation of cancer stem cells

Since the introduction of the cancer stem cell (CSC) paradigm, significant advances have been made in understanding the functional and biological plasticity of these elusive components in malignancies. Endowed with self-renewing abilities and multilineage differentiation potential, CSCs have emerged as cellular drivers of virtually all facets of tumor biology, including metastasis, tumor recurrence/relapse, and drug resistance. The functional and biological characteristics of CSCs, such as self-renewal, cell fate decisions, survival, proliferation, and differentiation are regulated by an array of extracellular factors, signaling pathways, and pluripotent transcriptional factors. Besides the well-characterized regulatory role of transcription factors OCT4, SOX2, NANOG, KLF4, and MYC in CSCs, evidence for the central role of Forkhead box transcription factor FOXM1 in the establishment, maintenance, and functions of CSCs is accumulating. Conventionally identified as a master regulator of the cell cycle, a comprehensive understanding of this molecule has revealed its multifarious oncogenic potential and uncovered its role in angiogenesis, invasion, migration, self-renewal, and drug resistance. This review compiles the large body of literature that has accumulated in recent years that provides evidence for the mechanisms by which FOXM1 expression promotes stemness in glioblastoma, breast, colon, ovarian, lung, hepatic, and pancreatic carcinomas. We have also compiled the data showing the association of stem cell mediators with FOXM1 using TCGA mRNA expression data. Further, the prognostic importance of FOXM1 and other stem cell markers is presented. The delineation of FOXM1-mediated regulation of CSCs can aid in the development of molecularly targeted pharmacological approaches directed at the selective eradication of CSCs in several human malignancies.

SOX2 contributes to invasion and poor prognosis of gastric cancer: A meta-analysis

BACKGROUND

The sex-determining region Y-box 2 (SOX2) has been identified to be involved in tumor progression and prognosis in patients with gastric cancer (GC). However, its action is paradoxical. Thus, we conducted the first meta-analysis based on eligible studies to evaluate the clinical utility of SOX2 in GC only.

METHODS

A thorough electronic search was performed to collect eligible studies. The hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were generated from included studies to assess the strength of the association between SOX2 and prognosis and clinicopathological characteristics in GC.

RESULTS

A total of 10 studies comprising 1321 patients with GC were identified for the meta-analysis. The pooled results revealed that high SOX2 expression was significantly associated with poor overall survival compared to low SOX2 expression (pooled HR = 1.485; 95% CI: 1.022-2.160; 𝑃 = .04). The statistical significance between SOX2 expression and overall survival was also established in univariate analysis (pooled HR = 1.606; 95% CI: 1.134-2.274; 𝑃 < .01), as well as recruitment time exceeding 2010 (pooled HR = 1.873; 95% CI: 1.041-3.371; 𝑃 = .04), follow-up time more than 5 years (pooled HR = 1.642; 95% CI: 1.066-2.527; 𝑃 = .02), and cutoff value of more than 5% of cells stained (pooled HR = 1.730; 95% CI: 1.162-2.577; 𝑃 < .01). Moreover, we verified that positive SOX2 expression was correlated with advanced tumor invasion depth (pooled OR = 0.494; 95% CI: 0.362-0.675; 𝑃 < .01) and positive vascular invasion (pooled OR = 1.515; 95% CI: 1.078-2.130; 𝑃 = .02).

CONCLUSION

SOX2 could not only be an independent prognostic marker in GC but might also be a novel target for cancer therapy.

TNF-α-inducing protein of Helicobacter pylori promotes EMT and cancer stem-like cells properties via activation of Wnt/β-catenin signaling pathway in gastric cancer cells

Tumor necrosis factor-α-inducing protein (Tipα) is a newly identified toxin, which promotes the inflammation and carcinogenesis caused by Helicobacter pylori (H. pylori). However, its mechanism of pathogenesis is still unclear. To investigate the carcinogenic mechanisms of Tipα, SGC7901 cells and SGC7901-derived cancer stem-like cells (CSCs) were stimulated by recombinant Tipα protein with or without Wnt/β-catenin signaling inhibitor XAV939. qRT-PCR and Western blotting were employed to detect expression of epithelial-mesenchymal transition (EMT), CSCs markers, and downstream target genes of this signaling pathway. The cell migration ability was measured by wound healing assay and transwell assay. Our results indicated that Tipα promoted CSC properties of SGC7901 spheroids, including increased expression of CSC specific surface markers CD44, Oct4, Nanog, and an increased capacity for self-renewal. Tipα activated Wnt/β-catenin signaling in both SGC7901 cells or CSCs. Furthermore, Tipα induced the EMT and increased the expressions of downstream target genes of this signaling, including c-myc, cyclin D1, and CD44. However, XAV939 pretreatment inhibited Tipα-induced EMT and CSC properties in SGC7901 cells or CSCs. These results suggest that Tipα promotes EMT and CSC-like properties in gastric cancer cells through activation of Wnt/β-catenin signaling pathway, thereby accelerating the progression of gastric cancer.

Nanog, as a key cancer stem cell marker in tumor progression

Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.

Zinc-finger protein 750 mitigates malignant biological behavior of oral CSC-like cells enriched from parental CAL-27 cells

Oral squamous cell carcinoma (OSCC) is the most commonly occurring oral malignancy. Cancer stem cells (CSCs) are known to be responsible for cancer recurrence and metastasis. Zinc-finger protein 750 (ZNF750) has been reported to inhibit OSCC cell proliferation and invasion. The present study aimed to elucidate the role of ZNF750 in the inhibition of the renewal ability of CSCs derived from the OSCC cell line, CAL-27. The effects of ZNF750 on CSC-like properties were examined using aldehyde dehydrogenase (ALDH), tumor sphere formation and colony formation assays. Reverse transcription-quantitative PCR and western blotting were performed to detect the expression levels of octamer-binding transcription factor 4, sex-determining region Y-box 2, the enhancer of zeste homolog 2 (Ezh2), embryonic ectoderm development (EED) and SUZ12 polycomb repressive complex 2 subunit (SUZ12), and for the identification of genes associated with metastasis. ZNF750 effectively attenuated CSC-like cell self-renewal abilities; ZNF750 decreased the ALDH-positive cell population, tumor sphere and colony formation abilities, cell viability and stemness factors. Furthermore, the expression levels of Ezh2, EED and SUZ12 were decreased by ZNF750. ZNF750 inhibited MMP1, 3, 9 and 13 expression levels, and decreased the cell invasion and migratory abilities. Moreover, the expression of tissue inhibitors of matrix metalloproteinases-1 was increased by ZNF750. However, opposite effects were observed following the knockdown of the ZNF750 gene. Overall, the present study demonstrated that ZNF750 has the potential to inhibit the renewal of CSC-like cells enriched from parental CAL-27 cells.

Faciogenital dysplasia 5 confers the cancer stem cell-like traits of gastric cancer cells through enhancing Sox2 protein stability

The promoting roles of faciogenital dysplasia 5 (FGD5) in tumor progression have been identified in various tumors, however, its roles in gastric cancer progression are still confusing. Currently, it was found that FGD5 was highly expressed in gastric cancer tissues and negatively correlated with different types of survival of gastric cancer patients via online dataset analysis. In vitro analysis of different types of gastric cancer cell lines and normal gastric epithelial cells obtained a consistent result. Then FGD5 was knocked down in gastric cancer cell lines through two independent siRNAs against FGD5 and it was identified that FGD5 knockdown suppressed the cancer stem cell (CSC)-like traits of gastric cancer cells through analyzing the expression of CSC markers, ALDH1 activity and spheroid-formation ability. Further mechanistic studies revealed that FGD5 interacted with Sox2 protein, a critical regulator of CSC progression, enhanced Sox2 protein stability and decreased its ubquitination. Additionally, FGD5 supported the CSC-like traits dependent on Sox2 expression. Taken together, this work identified a novel FGD5/Sox2 axis responsible for the CSC-like traits of gastric cancer cells.

Identification and validation of LGR5-binding peptide for molecular imaging of gastric cancer

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) is a stem cell marker in gastric cancer. In this study, we aimed to produce the LGR5-targeting peptide probe for the use of molecular imaging for gastric cancer. We used phage display libraries to produce a LGR5-specific peptide probe. This peptide was validated for targeting gastric cancer with in vitro and in vivo studies. This peptide was tagged with fluorescein isothiocyanate (FITC) and cyanine 5.5 (Cy5.5). We used two normal and three gastric cancer cell lines. Immunocytochemistry (ICC) and fluorescence-activated cell sorting (FACS) analysis were used to validate the target specificity of the peptide. After three rounds of bio-panning, we found a novel 7-mer peptides, IPQILSI (IPQ∗). FITC-conjugated IPQ∗ showed 2 to 10 times higher fluorescence in gastric cancer cells vs. control cells in ICC. This discrimination was consistently observed using Cy5.5-conjugated IPQ∗ in ICC. FACS analysis showed right shift of peak point in gastric cancers compared to the control cells. In the peritoneal metastasis animal model, we could find Cy5.5-conjugated IPQ∗ accumulated specifically to gastric tumors. In conclusion, IPQ∗ peptide showed a specific probe for gastric cancer diagnosis. This probe can be applied to theragnosis for gastric cancer diagnosis including peritoneal metastasis.

Conjugates Derived from Lapatinib Derivatives with Cancer Cell Stemness Inhibitors Effectively Reversed Drug Resistance in Triple-Negative Breast Cancer

Increasing evidence indicates that the cancer stem cell (CSC) subpopulation contributes to the therapeutic resistance and metastasis of tumors, leading to patient recurrence and death. Herein, we designed and synthesized several compounds by conjugating lapatinib derivatives with different CSC inhibitors to treat with lapatinib-induced MDA-MB-231 drug-resistant cells. In vitro biological studies indicated that 3a showed strong cytotoxicity and EGFR enzyme inhibitory activity and effectively reversed lapatinib-mediated resistance of MDA-MB-231 cells via inhibiting triple-negative breast cancer (TNBC) cell stemness and the AKT/ERK signaling pathway. In addition, 3a was capable of strongly suppressing the invasion and migration of TNBC cells by inhibiting the Wnt/β-catenin signaling pathway and MMP-2 and MMP-9 protein expression. In vivo tumorigenicity tests showed that 3a could inhibit the occurrence of TNBC by inhibiting BCSCs, proving 3a is a potential EGFR and CSC dual inhibitor for TNBC treatment.

SOX2 and Bcl-2 as a Novel Prognostic Value in Hepatocellular Carcinoma Progression

Sex-determining region Y-box 2 (SOX2) is a stem cell transcription factor and a major regulator of self-renewal and pluripotency of cancer stem cells (CSCs). In many types of cancer, SOX2 is dysregulated due to overexpression associated with tumor progression and low survival rate. Many HCC cases encounter recurrence and metastasis which might be due to CSCs and also apoptosis. Since little is known about the expression pattern of SOX2 and apoptotic genes in HCC, we aimed to determine the prognostic significance of SOX2, Bax, and Bcl-2 in clinicopathological features, tumor progression, and survival rate of the HCC patients. The expression of SOX2, Bax, and Bcl-2 were evaluated using qRT-PCR in 53 formalin-fixed, paraffin-embedded tissues (FFPE) of patients and 44 controls. Correlation of these genes was analyzed with clinicopathological features and tumor progression. The correlationship between SOX2 expression and ALBI grade as prognostic indicators were calculated. Survival rates were determined by Kaplan–Meier survival curves. SOX2 and Bcl-2 were remarkably overexpressed in HCC patients compared to controls (p = 0.04 and p = 0.003, respectively). A significant association was found for both SOX2 and Bcl-2 overexpression with TNM staging (p = 0.02, p = 0.04) and tumor grading (p = 0.01, p = 0.003), respectively. A significant correlation was observed: patients with SOX2 overexpression had a lower 5-year overall survival rate (p = 0.04); however, there was no significant association between Bcl-2 and survival (p = 0.5). Collectively, overexpression of SOX2 and Bcl-2, alone or combined, may be a potential marker to evaluate prognosis and response to HCC treatment.

Nanog, in Cooperation with AP1, Increases the Expression of E6/E7 Oncogenes from HPV Types 16/18

Persistent infections with some types of human papillomavirus (HPV) constitute the major etiological factor for cervical cancer development. Nanog, a stem cell transcription factor has been shown to increase during cancer progression. We wanted to determine whether Nanog could modulate transcription of E6 and E7 oncogenes. We used luciferase reporters under the regulation of the long control region (LCR) of HPV types 16 and 18 (HPV16/18) and performed RT-qPCR. We found that Nanog increases activity of both viral regulatory regions and elevates endogenous E6/E7 mRNA levels in cervical cancer-derived cells. We demonstrated by in vitro mutagenesis that changes at Nanog-binding sites found in the HPV18 LCR significantly inhibit transcriptional activation. Chromatin immunoprecipitation (ChIP) assays showed that Nanog binds in vivo to the HPV18 LCR, and its overexpression increases its binding as well as that of c-Jun. Surprisingly, we observed that mutation of AP1-binding sites also affect Nanog's ability to activate transcription, suggesting cooperation between the two factors. We searched for putative Nanog-binding sites in the LCR of several HPVs and surprisingly found them only in those types associated with cancer development. Our study shows, for the first time, a role for Nanog in the regulation of E6/E7 transcription of HPV16/18.

Gastric Cancer Stem Cells: A Glimpse on Metabolic Reprogramming

Gastric cancer (GC) is one of the most widespread causes of cancer-related death worldwide. Recently, emerging implied that gastric cancer stem cells (GCSCs) play an important role in the initiation and progression of GC. This subpopulation comprises cells with several features, such as self-renewal capability, high proliferating rate, and ability to modify their metabolic program, which allow them to resist current anticancer therapies. Metabolic pathway intermediates play a pivotal role in regulating cell differentiation both in tumorigenesis and during normal development. Thus, the dysregulation of both anabolic and catabolic pathways constitutes a significant opportunity to target GCSCs in order to eradicate the tumor progression. In this review, we discuss the current knowledge about metabolic phenotype that supports GCSC proliferation and we overview the compounds that selectively target metabolic intermediates of CSCs that can be used as a strategy in cancer therapy.

Vitamin D modulation and microRNAs in gastric cancer: prognostic and therapeutic role

Gastric adenocarcinoma arises after a complex interaction between the host and environmental factors. Tumor location and TNM are the tools that currently guide treatment decisions. Surgery is the only curative treatment, but relapse is common. After relapse or advanced staged disease survival is poor and systemic treatment has modestly improved survival. An association between sun exposure, vitamin D status and gastric cancer (GC) incidence and mortality has been reported. The molecular differences of the histological subtypes and the new molecular classifications account for the great heterogeneity of this disease and are the basis for the discovery of new therapeutic targets. New prognostic and predictive factors are essential and microRNAs (miRNAs) are endogenous small non-coding RNA molecules with a great potential for diagnosis, prognosis and treatment of cancer. There are hundreds of miRNAs with altered expression in tumor gastric tissue when compared to normal gastric tissue. Many of these miRNAs are associated with clinicopathological variables and survival in patients with GC. Furthermore, the expression of some of these miRNAs with prognostic importance in CG is influenced by vitamin D and others are mediators of some of the actions of this vitamin. This review aims to update the evidence on several miRNAs with prognostic value and therapeutic potential in GC, whose expression may be influenced by vitamin D or may regulate vitamin D signaling.

Isolation and Characterization of Human Colon Adenocarcinoma Stem-Like Cells Based on the Endogenous Expression of the Stem Markers

BACKGROUND

Cancer stem cells' (CSCs) self-maintenance is regulated via the pluripotency pathways promoting the most aggressive tumor phenotype. This study aimed to use the activity of these pathways for the CSCs' subpopulation enrichment and separating cells characterized by the OCT4 and SOX2 expression.

METHODS

To select and analyze CSCs, we used the SORE6x lentiviral reporter plasmid for viral transduction of colon adenocarcinoma cells. Additionally, we assessed cell chemoresistance, clonogenic, invasive and migratory activity and the data of mRNA-seq and intrinsic disorder predisposition protein analysis (IDPPA).

RESULTS

We obtained the line of CSC-like cells selected on the basis of the expression of the OCT4 and SOX2 stem cell factors. The enriched CSC-like subpopulation had increased chemoresistance as well as clonogenic and migration activities. The bioinformatic analysis of mRNA seq data identified the up-regulation of pluripotency, development, drug resistance and phototransduction pathways, and the downregulation of pathways related to proliferation, cell cycle, aging, and differentiation. IDPPA indicated that CSC-like cells are predisposed to increased intrinsic protein disorder.

CONCLUSION

The use of the SORE6x reporter construct for CSCs enrichment allows us to obtain CSC-like population that can be used as a model to search for the new prognostic factors and potential therapeutic targets for colon cancer treatment.

Discovery of 5-(3-Chlorophenylamino)benzo[c][2,6]naphthyridine Derivatives as Highly Selective CK2 Inhibitors with Potent Cancer Cell Stemness Inhibition

Multifunctional entities have recently been attractive for the development of anticancer chemotherapeutic drugs. However, such entities with concurrent CK2 along with cancer stem cell (CSC) inhibitory activities are rare in a single small molecule. Herein, a series of 5-(3-chlorophenylamino)benzo[c][2,6]naphthyridine derivatives were synthesized using a known CK2 inhibitor, silmitasertib (CX-4945), as the lead compound. Among the resulting compounds, 1c exhibited stronger CK2 inhibitory activity with higher Clk2/CK2 selectivity than CX-4945. Significantly, 1c could modulate the Akt1(ser129)-GSK-3β(ser9)-Wnt/β-catenin signaling pathway and inhibit the expression of the stemness marker ALDH1A1, CSC surface antigens, and stem genes, showing potent CSC inhibitory activity. Moreover, 1c also displayed superior pharmacokinetics and antitumor activity compared with CX-4945 sodium salt, without obvious toxicity. The favorable antiproliferative and antitumor activity of 1c, its high inhibitory selectivity for CK2, and its potent inhibition of cancer cell stemness make this molecule a candidate for the treatment of cancer.

The role of SOX family transcription factors in gastric cancer

Gastric cancer (GC) is a leading cause of death worldwide. GC is the third-most common cause of cancer-related death after lung and colorectal cancer. It is also the fifth-most commonly diagnosed cancer. Accumulating evidence has revealed the role of signaling networks in GC progression. Identification of these molecular pathways can provide new insight into therapeutic approaches for GC. Several molecular factors involved in GC can play both onco-suppressor and oncogene roles. Sex-determining region Y (Sry)-box-containing (SOX) family members are transcription factors with a well-known role in cancer. SOX proteins can bind to DNA to regulate cellular pathways via a highly conserved domain known as high mobility group (HMG). In the present review, the roles of SOX proteins in the progression and/or inhibition of GC are discussed. The dual role of SOX proteins as tumor-promoting and tumor-suppressing factors is highlighted. SOX members can affect upstream mediators (microRNAs, long non-coding RNAs and NF-κB) and down-stream mediators (FAK, HIF-1α, CDX2 and PTEN) in GC. The possible role of anti-tumor compounds to target SOX pathway members in GC therapy is described. Moreover, SOX proteins may be used as diagnostic or prognostic biomarkers in GC.

Could gastrointestinal tumor-initiating cells originate from cell-cell fusion in vivo?

Tumor-initiating cells (TICs) or cancer stem cells are believed to be responsible for gastrointestinal tumor initiation, progression, metastasis, and drug resistance. It is hypothesized that gastrointestinal TICs (giTICs) might originate from cell-cell fusion. Here, we systemically evaluate the evidence that supports or opposes the hypothesis of giTIC generation from cell-cell fusion both in vitro and in vivo. We review giTICs that are capable of initiating tumors in vivo with 5000 or fewer in vivo fused cells. Under this restriction, there is currently little evidence demonstrating that giTICs originate from cell-cell fusion in vivo. However, there are many reports showing that tumor generation in vitro occurs with more than 5000 fused cells. In addition, the mechanisms of giTIC generation via cell-cell fusion are poorly understood, and thus, we propose its potential mechanisms of action. We suggest that future research should focus on giTIC origination from cell-cell fusion in vivo, isolation or enrichment of giTICs that have tumor-initiating capabilities with 5000 or less in vivo fused cells, and further clarification of the underlying mechanisms. Our review of the current advances in our understanding of giTIC origination from cell-cell fusion may have significant implications for the understanding of carcinogenesis and future cancer therapeutic strategies targeting giTICs.

Escherichia coli foster bladder cancer cell line progression via epithelial mesenchymal transition, stemness and metabolic reprogramming

Bacteria is recognized as opportunistic tumor inhabitant, giving rise to an environmental stress that may alter tumor microenvironment, which directs cancer behavior. In vitro infection of the T24 cell line with E. coli was performed to study the bacterial impact on bladder cancer cells. EMT markers were assessed using immunohistochemistry, western blot and RT-PCR. Stemness characteristics were monitored using RT-PCR. Furthermore, the metabolic reprograming was investigated by detection of ROS and metabolic markers. A significant (p ≤ 0.001) upregulation of vimentin as well as downregulation of CK19 transcription and protein levels was reported. A significant increase (p ≤ 0.001) in the expression level of stemness markers (CD44, NANOG, SOX2 and OCT4) was reported. ROS level was elevated, that led to a significant increase (p ≤ 0.001) in UCP2. This enhanced a significant increase (p ≤ 0.001) in PDK1 to significantly downregulate PDH (p ≤ 0.001) in order to block oxidative phosphorylation in favor of glycolysis. This resulted in a significant decrease (p ≤ 0.001) of AMPK, and a significant elevation (p ≤ 0.001) of MCT1 to export the produced lactate to extracellular matrix. Thus, bacteria may induce alteration to the heterogonous tumor cell population through EMT, CSCs and metabolic reprogramming, which may improve cancer cell ability to migrate and self-renew.

Prognostic value of octamer binding transcription factor 4 for patients with solid tumors: A meta-analysis

BACKGROUND

Octamer binding transcription factor 4 (Oct4) is critically important in the development and progression of cancer, and is considered a potential biomarker for tumor prognosis. However, the prognostic value of Oct4 in patients with solid tumors remains elusive. Herein, we conducted a meta-analysis to assess the prognostic value of Oct4 in patients with solid tumors.

METHODS

We conducted a literature search on PubMed, Embase, and Web of Science databases to retrieve comprehensive and eligible studies published until December 2019. The study was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of overall survival (OS) and disease-free survival (DFS)/recurrence-free survival (RFS)/progress-free survival (PFS) were used to evaluate the prognostic value of Oct4 in patients with solid tumors via either random or fixed-effects models.

RESULTS

In total, 36 studies with 5198 patients were included in the meta-analysis. Notably, elevated Oct4 expression was associated with worse OS (pooled HR: 2.02, 95% CI: 1.55-2.62, P < .001) and DFS/RFS/PFS (pooled HR: 2.34, 95% CI: 1.88-2.92, P < .001).

CONCLUSION

This work demonstrated that patients with solid tumors show high expression of Oct4 which is linked to worse prognosis in patients with solid tumors including hepatocellular carcinoma (OS, DFS/RFS/PFS), esophageal squamous cell carcinoma (OS), gastric cancer (OS), cervical cancer (OS, DFS/RFS/PFS), and colorectal cancer (OS, DFS/RFS/PFS), this implicated Oct4 as a potential biomarker to predict the prognosis of tumors.

The oncogenic potential of NANOG: An important cancer induction mediator

Cancer stem cells (CSCs) are a unique population in the tumor, but they only comprise 2%-5% of the tumor bulk. Although CSCs share several features with embryonic stem cells, CSCs can give rise to the tumor cells. CSCs overexpress embryonic transcription factor NANOG, which is downregulated in differentiated tissues. This transcription factor confers CSC's stemness, unlimited self-renewal, metastasis, invasiveness, angiogenesis, and drug-resistance with the assistance of WNT, OCT4, SOX2, Hedgehog, BMI-1, and other complexes. NANOG facilitates CSCs development via multiple pathways, like angiogenesis and lessening E-cadherin expression levels, which paves the road for metastasis. Moreover, NANOG represses apoptosis and leads to drug-resistance. This review aims to highlight the pivotal role of NANOG and the pertained pathways in CSCs. Also, this current study intends to demonstrate that targeting NANOG can dimmish the CSCs, sensitize the tumor to chemotherapy, and eradicate the cancer cells.

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.

The Relevance of Transcription Factors in Gastric and Colorectal Cancer Stem Cells Identification and Eradication

Gastric and colorectal cancers have a high incidence and mortality worldwide. The presence of cancer stem cells (CSCs) within the tumor mass has been indicated as the main reason for tumor relapse, metastasis and therapy resistance, leading to poor overall survival. Thus, the elimination of CSCs became a crucial goal for cancer treatment. The identification of these cells has been performed by using cell-surface markers, a reliable approach, however it lacks specificity and usually differs among tumor type and in some cases even within the same type. In theory, the ideal CSC markers are those that are required to maintain their stemness features. The knowledge that CSCs exhibit characteristics comparable to normal stem cells that could be associated with the expression of similar transcription factors (TFs) including SOX2, OCT4, NANOG, KLF4 and c-Myc, and signaling pathways such as the Wnt/β-catenin, Hedgehog (Hh), Notch and PI3K/AKT/mTOR directed the attention to the use of these similarities to identify and target CSCs in different tumor types. Several studies have demonstrated that the abnormal expression of some TFs and the dysregulation of signaling pathways are associated with tumorigenesis and CSC phenotype. The disclosure of common and appropriate biomarkers for CSCs will provide an incredible tool for cancer prognosis and treatment. Therefore, this review aims to gather the new insights in gastric and colorectal CSC identification specially by using TFs as biomarkers and divulge promising drugs that have been found and tested for targeting these cells.

Immunohistochemical analysis of SOX2 expression in small-cell neuroendocrine carcinoma of the endometrium

Small-cell neuroendocrine carcinoma (NEC) of the endometrium is an extremely rare and highly aggressive carcinoma. Sex-determining region Y-box 2 (SOX2) is a master transcription factor regulating the self-renewal, maintenance of stem cell properties and pluripotency of embryonic stem cells, and recent studies revealed that SOX2 plays important roles in cancer growth and progression in several types of carcinomas, including small-cell neuroendocrine carcinoma (NEC) of the lung and oesophagus. Few studies to date have analysed the association between SOX2 and endometrioid carcinoma, whereas the expression of SOX2 in small-cell NEC of the endometrium has not been investigated. The aim of the present study was to analyse the expression status of SOX2, p16 and paired-box gene (PAX) 8, a useful Müllerian marker, in endometrial small-cell NEC. A total of 4 patients with small-cell NEC of the endometrium were enrolled (median age, 70 years). Immunohistochemical studies revealed SOX2 expression in 3 patients and p16 expression in all patients. No patients exhibited positive immunoreactivity for PAX8. SOX2 expression has been reported to be associated with the pathogenesis of small-cell NEC of the oesophagus. Therefore, the results of the present study indicated that SOX2 expression plays an important role in the development of small-cell NEC of the endometrium and the oesophagus. Moreover, expression of p16 and loss of PAX8 do not indicate the origin of small-cell NEC of the endometrium.

NANOG expression in human development and cancerogenesis

NANOG is an important stem cell transcription factor involved in human development and cancerogenesis. Its expression is complex and regulated on different levels. Moreover, NANOG protein might regulate hundreds of target genes at the same time. NANOG is crucial for preimplantation development phase and progressively decreases during embryonic stem cells differentiation, thus regulating embryonic and fetal development. Postnatally, NANOG is undetectable or expressed in very low amounts in the majority of human tissues. NANOG re-expression can be detected during cancerogenesis, already in precancerous lesions, with increasing levels of NANOG in high grade dysplasia. NANOG is believed to enable cancer cells to obtain stem-cell like properties, which are believed to be the source of expanding growth, tumor maintenance, metastasis formation, and tumor relapse. High NANOG expression in cancer is frequently associated with advanced stage, poor differentiation, worse overall survival, and resistance to treatment, and is therefore a promising prognostic and predictive marker. We summarize the current knowledge on the role of NANOG in cancerogenesis and development, including our own experience. We provide a critical overview of NANOG as a prognostic and diagnostic factor, including problems regarding its regulation and detection.

Zinc Finger Protein 521, Negatively Regulated by MicroRNA-204-5p, Promotes Proliferation, Motility and Invasion of Gastric Cancer Cells

OBJECTIVE

This study aims to investigate the expression, role, and detailed mechanism of microRNA-204-5p and zinc finger protein 521 in gastric cancer.

METHODS

Immunohistochemistry was adopted to detect the expressions of zinc finger protein 521 in 82 cases of gastric cancer tissues. Western blot was used to detect the expressions of zinc finger protein 521 in gastric cancer cells and adjacent cells. Moreover, the correlation between zinc finger protein 521 and the prognosis of patients were also evaluated. Cell Counting Kit 8 assay and colony formation assay were performed to figure out the impact of zinc finger protein 521 on the proliferation of gastric cancer cells. By conducting flow cytometry, the effect of zinc finger protein 521 on the apoptosis of gastric cancer cells was determined. The scratch wound healing assay and transwell invasion assay were carried out to determine the effect of zinc finger protein 521 on regulating the motility and invasion of gastric cancer cells. Ultimately, the targeting relationship and interaction between microRNA-204-5p and zinc finger protein 521 were verified by real-time polymerase chain reaction, Western blot, and dual luciferase reporter gene assay.

RESULTS

Compared with adjacent cells, zinc finger protein 521 was highly expressed in gastric cancer cells, which was related to TNM stage (P = .0388), tumor size (P = .0168), and local lymph node metastasis (P = .0024). Overexpressed zinc finger protein 521 can promote the proliferation, migration, and invasion of gastric cancer cells and inhibit the apoptosis. Zinc finger protein 521 is a target gene of microRNA-106-5p, and there was a negative correlation between the expression of zinc finger protein 521 and microRNA-204-5p.

CONCLUSION

Zinc finger protein 521 can arrest the apoptosis and enhance the proliferation, migration, and invasion of gastric cancer cells via regulating microRNA-204-5p. Our study may provide novel clues for the treatment of patients with gastric cancer.

CMIP promotes Herceptin resistance of HER2 positive gastric cancer cells

Gastric cancer remains one of the most malignant human cancers with poor prognosis. Herceptin is a well-received antibody drug for HER2 positive gastric cancer. Primary Herceptin resistance and acquired Herceptin resistance retarded the use of Herceptin for gastric cancer. We herein reported CMIP (C-Maf-inducing protein) was overexpressed in Herceptin-resistant gastric cancer cells MKN45-HR and NCI-N87-HR; CMIP promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 was examined to be positively regulated by CMIP and also promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 might mediate the Herceptin resistance promoting role of CMIP in gastric cancer cells. Elevated expression of CMIP was associated with poor clinicopathological features including tumor size, lymph node metastasis and clinical stage in HER2 positive gastric cancer patients. Inhibitors of CMIP could be used as potential adjuvant therapeutic drugs for HER2 positive gastric cancer.

Oct4 expression in gastric carcinoma: association with tumor proliferation, angiogenesis and survival

BACKGROUND

Octamer-binding transcription factor 4 (Oct4) is a transcription factor that has an important role in stem cell differentiation and self-renewal. Oct4 has also been implicated in tumorigenicity of different cancers. This study aimed to analyze Oct4 expression in gastric carcinoma (GC) and to evaluate the relation between Oct4 expression and clinicopathologic parameters, tumor proliferation, and angiogenesis in addition to patient survival.

RESULTS

Oct4 mRNA was detected by quantitative reverse transcription PCR (qRT-PCR) in 45 GC specimens and adjacent non-cancerous tissues. We found a significant difference in Oct4 mRNA relative expression levels in GC tissue compared with adjacent non-cancerous tissues (p < 0.001). Furthermore, immunohistochemistry (IHC) was performed to study the Oct4 expression in GC cases. High Oct4 immunostaining was detected in 62.2% of GC specimens. High Oct4 expression both by mRNA relative quantitation and IHC were significantly related to poorly differentiated tumors, nodal metastasis, and stage III tumors. Moreover, high Oct4 IHC expression was also associated with cases positive for Ki-67 and VEGF expressions (p < 0.001 and 0.021, respectively). Oct4 expression identified by both mRNA relative quantitation and IHC was significantly related (p < 0.001). As regards patient survival, high Oct4 expression was significantly related to poor overall survival (OS) and disease-free survival (DFS) (p = 0.029 and 0.031, respectively).

CONCLUSION

Oct4 plays a valuable role in the progression and prognosis of GC. High Oct4 expression is associated with high tumor grade, nodal metastasis, stage III tumors, and poor OS and DFS. High Oct4 is also significantly associated with Ki-67 and VGEF expression, thus enhancing tumor proliferation and angiogenesis.