Sox2 modulates motility and enhances progression of colorectal cancer via the Rho-ROCK signaling pathway

Navigating therapeutic prospects by modulating autophagy in colorectal cancer

Colorectal cancer (CRC) remains a leading cause of death globally despite the improvements in cancer treatment. Autophagy is an evolutionarily conserved lysosomal-dependent degradation pathway that is critical in maintaining cellular homeostasis. However, in cancer, autophagy may have conflicting functions in preventing early tumour formation versus the maintenance of advanced-stage tumours. Defective autophagy has a broad and dynamic effect not just on cancer cells, but also on the tumour microenvironment which influences tumour progression and response to treatment. To add to the layer of complexity, somatic mutations in CRC including tumour protein p53 (TP53), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), Kirsten rat sarcoma viral oncogene homolog (KRAS), and phosphatase and tensin homolog (PTEN) can render chemoresistance by promoting a pro-survival advantage through autophagy. Recent studies have also reported autophagy-related cell deaths that are distinct from classical autophagy by employing parts of the autophagic machinery, which impacts strategies for autophagy regulation in cancer therapy. This review discusses the molecular processes of autophagy in the evolution of CRC and its role in the tumour microenvironment, as well as prospective therapeutic methods based on autophagy suppression or promotion. It also highlights clinical trials using autophagy modulators for treating CRC, underscoring the importance of autophagy regulation in CRC therapy.

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.

Transcriptomic analysis and fusion gene identifications of midbody remnants released from colorectal cancer cells reveals they are molecularly distinct from exosomes and microparticles

Previously, we reported that human primary (SW480) and metastatic (SW620) colorectal (CRC) cells release three classes of membrane-encapsulated extracellular vesicles (EVs); midbody remnants (MBRs), exosomes (Exos), and microparticles (MPs). We reported that MBRs were molecularly distinct at the protein level. To gain further biochemical insights into MBRs, Exos, and MPs and their emerging role in CRC, we performed, and report here, for the first time, a comprehensive transcriptome and long noncoding RNA sequencing analysis and fusion gene identification of these three EV classes using the next-generation RNA sequencing technique. Differential transcript expression analysis revealed that MBRs have a distinct transcriptomic profile compared to Exos and MPs with a high enrichment of mitochondrial transcripts lncRNA/pseudogene transcripts that are predicted to bind to ribonucleoprotein complexes, spliceosome, and RNA/stress granule proteins. A salient finding from this study is a high enrichment of several fusion genes in MBRs compared to Exos, MPs, and cell lysates from their parental cells such as MSH2 (gene encoded DNA mismatch repair protein MSH2). This suggests potential EV-liquid biopsy targets for cancer detection. Importantly, the expression of cancer progression-related transcripts found in EV classes derived from SW480 (EGFR) and SW620 (MET and MACCA1) cell lines reflects their parental cell types. Our study is the report of RNA and fusion gene compositions within MBRs (including Exos and MPs) that could have an impact on EV functionality in cancer progression and detection using EV-based RNA/ fusion gene candidates for cancer biomarkers.

5-Fluorouracil dose escalation generated desensitized colorectal cancer cells with reduced expression of protein methyltransferases and no epithelial-to-mesenchymal transition potential

Background

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers. In many cases, the poor prognosis of advanced CRC is associated with resistance to treatment with chemotherapeutic drugs such as 5-Fluorouracil (5-FU). The epithelial-to-mesenchymal transition (EMT) and dysregulation in protein methylation are two mechanisms associated with chemoresistance in many cancers. This study looked into the effect of 5-FU dose escalation on EMT and protein methylation in CRC.

Materials and Methods

HCT-116, Caco-2, and DLD-1 CRC cell lines were exposed to dose escalation treatment of 5-FU. The motility and invasive potentials of the cells before and after treatment with 5-FU were investigated through wound healing and invasion assays. This was followed by a Western blot which analyzed the protein expressions of the epithelial marker E-cadherin, mesenchymal marker vimentin, and the EMT transcription factor (EMT-TF), the snail family transcriptional repressor 1 (Snail) in the parental and desensitized cells. Western blotting was also conducted to study the protein expressions of the protein methyltransferases (PMTs), Euchromatic histone lysine methyltransferase 2 (EHMT2/G9A), protein arginine methyltransferase (PRMT5), and SET domain containing 7/9 (SETD7/9) along with the global lysine and arginine methylation profiles.

Results

The dose escalation method generated 5-FU desensitized CRC cells with distinct morphological features and increased tolerance to high doses of 5-FU. The 5-FU desensitized cells experienced a decrease in migration and invasion when compared to the parental cells. This was reflected in the observed reduction in E-cadherin, vimentin, and Snail in the desensitized cell lines. Additionally, the protein expressions of EHMT2/G9A, PRMT5, and SETD7/9 also decreased in the desensitized cells and global protein lysine and arginine methylation became dysregulated with 5-FU treatment.

Conclusion

This study showed that continuous, dose-escalation treatment of 5-FU in CRC cells generated 5-FU desensitized cancer cells that seemed to be less aggressive than parental cells.

Improvement of 5-fluorouracil chemosensitivity in colorectal cancer cells by siRNA-mediated silencing of STAT6 oncogene

Objectives

Colorectal cancer (CRC) remains a major health concern worldwide due to its high incidence, mortality rate, and resistance to conventional treatments. The discovery of new targets for cancer therapy is essential to improve the survival of CRC patients. Here, this study aims to present a finding that identifies the STAT6 oncogene as a potent therapeutic target for CRC.

Materials and Methods

HT-29 CRC cells were transfected with STAT6 siRNA and treated with 5-fluorouracil (5-FU) alone and combined. Then, to evaluate cellular proliferation and apoptosis percentage, MTT assay and annexin V/PI staining were carried out, respectively. Moreover, the migration ability of HT-29 cells was followed using a wound-healing assay, and a colony formation assay was performed to explore cell stemness features. Gene expression was quantified via qRT-PCR. Afterward, functional enrichment analysis was used to learn in-depth about the STAT6 co-expressed genes and the pathways to which they belong.

Results

Our study shows that silencing STAT6 with small interfering RNA (siRNA) enhances the chemosensitivity of CRC cells to 5-FU, a commonly used chemotherapy drug, by inducing apoptosis, reducing proliferation, and inhibiting metastasis. These results suggest that combining 5-FU with STAT6-siRNA could provide a promising strategy for CRC treatment.

Conclusion

Our study sheds light on the potential of STAT6 as a druggable target for CRC cancers, the findings offer hope for more effective treatments for CRC patients, especially those with advanced stages that are resistant to conventional therapies.

Peristalsis-Associated Mechanotransduction Drives Malignant Progression of Colorectal Cancer

Introduction

In the colorectal cancer (CRC) tumor microenvironment, cancerous and precancerous cells continuously experience mechanical forces associated with peristalsis. Given that mechanical forces like shear stress and strain can positively impact cancer progression, we explored the hypothesis that peristalsis may also contribute to malignant progression in CRC. We defined malignant progression as enrichment of cancer stem cells and the acquisition of invasive behaviors, both vital to CRC progression.

Methods

We leveraged our peristalsis bioreactor to expose CRC cell lines (HCT116), patient-derived xenograft (PDX1,2) lines, or non-cancerous intestinal cells (HIEC-6) to forces associated with peristalsis in vitro. Cells were maintained in static control conditions or exposed to peristalsis for 24 h prior to assessment of cancer stem cell (CSC) emergence or the acquisition of invasive phenotypes.

Results

Exposure of HCT116 cells to peristalsis significantly increased the emergence of LGR5+ CSCs by 1.8-fold compared to static controls. Peristalsis enriched LGR5 positivity in several CRC cell lines, notably significant in KRAS mutant lines. In contrast, peristalsis failed to increase LGR5+ in non-cancerous intestinal cells, HIEC-6. LGR5+ emergence downstream of peristalsis was dependent on ROCK and Wnt activity, and not YAP1 activation. Additionally, HCT116 cells adopted invasive morphologies when exposed to peristalsis, with increased filopodia density and epithelial to mesenchymal gene expression, in a Wnt dependent manner.

Conclusions

Peristalsis associated forces drive malignant progression of CRC via ROCK, YAP1, and Wnt-related mechanotransduction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00776-w.

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.

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.

Autophagy: A Versatile Player in the Progression of Colorectal Cancer and Drug Resistance

Colorectal cancer (CRC) is among the topmost malignancies for both genders. Despite the high incidence rate and advances in diagnostic tools, treatment in many cases is still ineffective. Most cancerous lesions in CRC begin as benign, followed by the development of invasive forms and metastases. The development of CRC has been linked to defects in autophagy, which plays both a pro-and anti-tumor role and is mainly context-dependent. Autophagy suppression could enhance apoptosis via p53 activation, or autophagy also promotes tumor progression by maintaining tumor growth and increasing resistance to chemotherapy. Autophagy promotes the invasion and metastasis of CRC cells via increased epithelial-mesenchymal transition (EMT). Moreover, dysbiosis of gut microbiota upregulated autophagy and metastasis markers. Autophagy responses may also modulate the tumor microenvironment (TME) via regulating the differentiation process of several innate immune cells. Treatments that promote tumor cell death by stimulating or inhibiting autophagy could be beneficial if used as an adjunct treatment, but the precise role of various autophagy-modulating drugs in CRC patients is needed to be explored. In this article, we present an overview of the autophagy process and its role in the pathogenesis and therapeutic resistance of CRC. Also, we focused on the current understanding of the role of the EMT and TME, including its relation to gut microbiota and immune cells, in autophagic manipulation of CRC. We believe that there is a potential link between autophagy, TME, EMT, and drug resistance, suggesting that further studies are needed to explore this aspect.

Enhanced O-GlcNAc modification induced by the RAS/MAPK/CDK1 pathway is required for SOX2 protein expression and generation of cancer stem cells

Cancer stem cells (CSCs) have tumour initiation, self-renewal, and long-term tumour repopulation properties, and it is postulated that differentiated somatic cells can be reprogrammed to CSCs by oncogenic signals. We previously showed that oncogenic HRAS^V12 conferred tumour initiation capacity in tumour suppressor p53-deficient (p53^−/−) primary mouse embryonic fibroblasts (MEFs) through transcription factor NF-κB-mediated enhancement of glucose uptake; however, the underlying mechanisms of RAS oncogene-induced CSC reprogramming have not been elucidated. Here, we found that the expression of the reprogramming factor SOX2 was induced by HRAS^V12 in p53^−/− MEFs. Moreover, gene knockout studies revealed that SOX2 is an essential factor for the generation of CSCs by HRAS^V12 in mouse and human fibroblasts. We demonstrated that HRAS^V12-induced cyclin-dependent kinase 1 (CDK1) activity and subsequent enhancement of protein O-GlcNAcylation were required for SOX2 induction and CSC generation in these fibroblasts and cancer cell lines containing RAS mutations. Moreover, the CDK inhibitor dinaciclib and O-GlcNAcylation inhibitor OSMI1 reduced the number of CSCs derived from these cells. Taken together, our results reveal a signalling pathway and mechanism for CSC generation by oncogenic RAS and suggest the possibility that this signalling pathway is a therapeutic target for CSCs.

Photodynamic Therapy with Zinc Phthalocyanine Inhibits the Stemness and Development of Colorectal Cancer: Time to Overcome the Challenging Barriers?

Photodynamic therapy (PDT) is a light-based cancer therapy approach that has shown promising results in treating various malignancies. Growing evidence indicates that cancer stem cells (CSCs) are implicated in tumor recurrence, metastasis, and cancer therapy resistance in colorectal cancer (CRC); thus, targeting these cells can ameliorate the prognosis of affected patients. Based on our bioinformatics results, SOX2 overexpression is significantly associated with inferior disease-specific survival and worsened the progression-free interval of CRC patients. Our results demonstrate that zinc phthalocyanine (ZnPc)-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially decrease tumor migration via downregulating MMP9 and ROCK1 and inhibit the clonogenicity of SW480 cells via downregulating CD44 and SOX2. Despite inhibiting clonogenicity, ZnPc-PDT with 12 J/cm2 irradiation fails to downregulate CD44 expression in SW480 cells. Our results indicate that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially reduce the cell viability of SW480 cells and stimulate autophagy in the tumoral cells. Moreover, our results show that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially arrest the cell cycle at the sub-G1 level, stimulate the intrinsic apoptosis pathway via upregulating caspase-3 and caspase-9 and downregulating Bcl-2. Indeed, our bioinformatics results show considerable interactions between the studied CSC-related genes with the studied migration- and apoptosis-related genes. Collectively, the current study highlights the potential role of ZnPc-PDT in inhibiting stemness and CRC development, which can ameliorate the prognosis of CRC patients.

Isoform-specific effects of transcription factor TCFL5 on the pluripotency-related genes SOX2 and KLF4 in colorectal cancer development

Colorectal cancer (CRC) is a very common life‐threatening malignancy. Transcription factor‐like 5 (TCFL5) has been suggested to be involved in CRC. Here, we describe the expression of four alternative transcripts of TCFL5 and their relevance in CRC. Complete deletion of all isoforms drastically decreased pro‐tumoural properties such as spheroids formation and in vivo tumour growth, although increased migration in CRC cell lines. Overexpression of the two main isoforms, TCFL5_E8 and CHA, had opposite effects: TCFL5_E8 reduced proliferation and spheroids formation, while CHA increased them. TCFL5_E8 reduced in vivo tumour formation, while CHA had no effect. In addition, TCFL5_E8 and CHA have different roles in the regulation of the pluripotency‐related genes SOX2 and KLF4. Both isoforms bind directly to their promoters; however, TCFL5_E8 induced SOX2 and reduced KLF4 mRNA levels, whereas CHA did the opposite. Together, our results show that TCFL5 plays an important role in the development of CRC, being however isoform‐specific. This work also points to the need to analyse separately TCFL5 isoforms in cancer, due to their different and opposite functions.

NCOR1 Sustains Colorectal Cancer Cell Growth and Protects against Cellular Senescence

Simple Summary

NCOR1 is a scaffold protein that interacts with multiple partners to repress gene transcription. NCOR1 controls immunometabolic functions in several tissues and has been recently shown to protect against experimental colitis in mice. Our laboratory has observed a pro-proliferative role of NCOR1 in normal intestinal epithelial cells. However, it is unclear whether NCOR1 is functionally involved in colon cancer. This study demonstrated that NCOR1 is required for colorectal cancer cell growth. Depletion of NCOR1 caused these cells to become senescent. Transcriptomic signatures confirmed these observations but also predicted the potential for these cells to become pro-invasive. Thus, NCOR1 plays a novel role in preventing cancer-associated senescence and could represent a target for controlling colon cancer progression.

Abstract

NCOR1 is a corepressor that mediates transcriptional repression through its association with nuclear receptors and specific transcription factors. Some evidence supports a role for NCOR1 in neonatal intestinal epithelium maturation and the maintenance of epithelial integrity during experimental colitis in mice. We hypothesized that NCOR1 could control colorectal cancer cell proliferation and tumorigenicity. Conditional intestinal epithelial deletion of Ncor1 in Apc^Min/+ mice resulted in a significant reduction in polyposis. RNAi targeting of NCOR1 in Caco-2/15 and HT-29 cell lines led to a reduction in cell growth, characterized by cellular senescence associated with a secretory phenotype. Tumor growth of HT-29 cells was reduced in the absence of NCOR1 in the mouse xenografts. RNA-seq transcriptome profiling of colon cancer cells confirmed the senescence phenotype in the absence of NCOR1 and predicted the occurrence of a pro-migration cellular signature in this context. SOX2, a transcription factor essential for pluripotency of embryonic stem cells, was induced under these conditions. In conclusion, depletion of NCOR1 reduced intestinal polyposis in mice and caused growth arrest, leading to senescence in human colorectal cell lines. The acquisition of a pro-metastasis signature in the absence of NCOR1 could indicate long-term potential adverse consequences of colon-cancer-induced senescence.

Prognostic significance of MUC2, CDX2 and SOX2 in stage II colorectal cancer patients

Background

Colorectal cancer (CRC) remains a serious health concern worldwide. Despite advances in diagnosis and treatment, about 15 to 30% of stage II CRC patients subjected to tumor resection with curative intent, develop disease relapse. Moreover, the therapeutic strategy adopted after surgery is not consensual for these patients. This supports the imperative need to find new prognostic and predictive biomarkers for stage II CRC.

Methods

For this purpose, we used a one-hospital series of 227 stage II CRC patient samples to assess the biomarker potential of the immunohistochemical expression of MUC2 mucin and CDX2 and SOX2 transcription factors. The Kaplan-Meier method was used to generate disease-free survival curves that were compared using the log-rank test, in order to determine prognosis of cases with different expression of these proteins, different mismatch repair (MMR) status and administration or not of adjuvant chemotherapy.

Results

In this stage II CRC series, none of the studied biomarkers showed prognostic value for patient outcome. However low expression of MUC2, in cases with high expression of CDX2, absence of SOX2 or MMR-proficiency, conferred a significantly worst prognosis. Moreover, cases with low expression of MUC2 showed a significantly clear benefit from treatment with adjuvant chemotherapy.

Conclusion

In conclusion, we observe that patients with stage II CRC with low expression of MUC2 in the tumor respond better when treated with adjuvant chemotherapy. This observation supports that MUC2 is involved in resistance to fluorouracil-based adjuvant chemotherapy and might be a promising future predictive biomarker in stage II CRC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08070-6.

Isolation and Characterization of Two Novel Colorectal Cancer Cell Lines, Containing a Subpopulation with Potential Stem-Like Properties: Treatment Options by MYC/NMYC Inhibition

Simple Summary

The aim of this study was to gain a better understanding of cancer stem cells, which are a small subpopulation of tumor cells with high plasticity driving tumor growth and metastasis. Here we isolated two novel colorectal cancer cell lines originating from a rectal neuroendocrine carcinoma and a colorectal adenocarcinoma, depicting stem-like properties. These in vitro models offer the possibility to evaluate pathophysiological mechanisms in order to develop tailored therapeutic strategies for distinct colorectal malignancies. Investigations revealed gene copy number gain of the N-myc proto-oncogene for both. Accordingly, inhibition of the protein–protein interaction of myc and N-myc proto-oncogenes with the myc-associated factor X utilizing small molecule KJ-Pyr-9, exhibited a significant reduction in survival of both cell lines by the induction of apoptosis. Consequently, the blockage of these interactions may serve as a possible treatment strategy for colorectal cancer cell lines with gene copy number gain of the N-myc proto-oncogene.

Abstract

Cancer stem cells (CSC) are crucial mediators of cancer relapse. Here, we isolated two primary human colorectal cancer cell lines derived from a rectal neuroendocrine carcinoma (BKZ-2) and a colorectal adenocarcinoma (BKZ-3), both containing subpopulations with potential stem-like properties. Protein expression of CSC-markers prominin-1 and CD44 antigen was significantly higher for BKZ-2 and BKZ-3 in comparison to well-established colon carcinoma cell lines. High sphere-formation capacity further confirmed the existence of a subpopulation with potential stem-like phenotype. Epithelial–mesenchymal transition markers as well as immune checkpoint ligands were expressed more pronounced in BKZ-2. Both cell populations demonstrated N-myc proto-oncogene (NMYC) copy number gain. Myc proto-oncogene (MYC)/NMYC activity inhibitor all-trans retinoic acid (ATRA) significantly reduced the number of tumor spheres for both and the volume of BKZ-2 spheres. In contrast, the sphere volume of ATRA-treated BKZ-3 was increased, and only BKZ-2 cell proliferation was reduced in monolayer culture. Treatment with KJ-Pyr-9, a specific inhibitor of MYC/NMYC-myc-associated factor X interaction, decreased survival by the induction of apoptosis of both. In summary, here, we present the novel colorectal cancer cell lines BKZ-2 and BKZ-3 as promising cellular in vitro models for colorectal carcinomas and identify the MYC/NMYC molecular pathway involved in CSC-induced carcinogenesis with relevant therapeutic potential.

Increasing the colon cancer cells sensitivity toward radiation therapy via application of Oct4-Sox2 complex decoy oligodeoxynucleotides

Low sensitivity of cancer stem cells toward regular cancer therapy strategies is an important issue in the field of cancer remedy. The concept of cancer stem cell elimination has been a topic of interest in the field of molecular medicine for a long time. At the current study, it was aimed to elevate the sensitivity of cancer stem-like cells toward radiotherapy by treating with Oct4-Sox2 complex decoy oligodeoxynucleotides (ODNs). After treating HT29 and HT29-ShE cells with Oct4-Sox2 complex decoy ODNs, and analyzing the cellular uptake and localization of decoys, treated cells and control groups were subjected to irradiation by fractionated 6MV X-ray with a final dose of 2 Gy. Thereafter, the influence of radiotherapy on ODNs treated groups and control group was investigated on cell viability, cell cycle, apoptosis, colonosphere formation and scratch assay. Cellular uptake and localization assays demonstrated that decoy ODNs can efficiently be transfected to the cells and reside in subcellular compartment, where they pose their action on gene regulation. Post radiotherapy analysis indicated statistical significance in decoy ODNs treated cells by means of lower cell viability, cell cycle arrest in G2/M phase, increased cellular apoptosis, and reduced cell motility. Also, formed colonospheres were smaller in size and fewer in numbers. Considering the role of Oct4, and Sox2 transcription factors in signaling pathways of preserving stemness and inducing reverse EMT, application of decoy strategy could increase the sensitivity of cancer cells toward irradiation, which has a potential to eliminate the cancerous cells from tumors and support cancer treatment.

Clinical and Survival Impact of Sex-Determining Region Y-Box 2 in Colorectal Cancer: An Integrated Analysis of the Immunohistochemical Study and Bioinformatics Analysis

Transcription factor sex-determining region Y-box 2 (SOX2) involves in the maintenance of cancer stem cells. However, the role of SOX2 in colorectal cancer (CRC) remains unclear. This study was conducted to investigate the effect of SOX2 on CRC. Studies were searched using electronic databases. The combined odds ratios (ORs) or hazard ratios (HRs: multivariate Cox survival analysis) with their 95% confidence intervals (CIs) were calculated. The Cancer Genome Atlas (TCGA) and GEO datasets were further applied to validate the survival effect. The functional analysis of SOX2 was investigated. In this work, 13 studies including 2337 patients were identified, and validation data were enrolled from TCGA and GEO datasets. SOX2 expression was not significantly related to age, gender, microsatellite instability (MSI) status, clinical stage, histological grade, tumor size, pT-stage, lymph node metastasis, distal metastasis, and cancer-specific survival (CSS) but was correlated with worse overall survival (OS: n = 536 patients) (P < 0.05). Furthermore, TCGA data demonstrated similar results, with no significant correlation between SOX2 and pathological characteristics. Further validation data (OS: n = 1408 and disease-free survival (DFS): n = 1367) showed that SOX2 expression was correlated with worse OS (HR = 1.35, 95% CI: 1.11–1.65, P=0.004) and DFS (HR = 1.30, 95% CI: 1.04–1.62, P=0.02). The functional analyses showed that SOX2 involved in cell-cell junction, focal adhesion, extracellular matrix- (ECM-) receptor interaction, and MAP kinase activity. Our findings suggest that SOX2 expression may be correlated with the worse prognosis of CRC.

SRY‑related HMG box‑2 role in anaplastic thyroid cancer aggressiveness is related to the fibronectin 1 and PI3K/AKT pathway

Anaplastic thyroid cancer (ATC) is a rare thyroid tumor associated with high mortality rates; thus, the identification of novel molecular targets and the development of therapeutic strategies are urgently required. The present study aimed to investigate the role of SRY-related HMG box-2 (SOX2) in ATC cells and explore whether the underlying mechanism was associated with fibronectin 1 (FN1). The proliferative, migratory and invasive ability of ATC cell lines was investigated using Cell Counting Kit-8, colony formation, wound-healing and Transwell assays, respectively; SOX2 expression in FRO cells was knocked down using small interfering RNA and SOX2 overexpression in FRO cells was achieved using cDNA constructs; and reverse transcription-quantitative PCR and western blotting were used to identify the mechanism of action underlying the SOX-2 mediated increased in cell aggressive phenotypes. Increased protein expression levels of SOX2 protein were observed in ATC tissue, and FRO and 8505c ATC cell lines. SOX2 overexpression increased the cell viability, and proliferative, migratory and invasive abilities of FRO cell lines. SOX2 overexpression increased FN1, p65, phosphorylated PI3K and AKT expression levels, whereas the knockdown of SOX2 promoted the opposite effects. In conclusion, the present study suggested a possible model of SOX2-mediated gene regulation in ATC cells, in which the overexpression of SOX2 promoted FN1 expression via the PI3K/AKT signaling pathway to induce the aggressive phenotype of ATC. These findings may provide crucial molecular insights into ATC pathogenesis and may demonstrate potential to develop into novel therapeutic interventions for patients with ATC.

The association of SOX2 with clinical features and prognosis in colorectal cancer: A meta-analysis

OBJECTIVES

The expression of SOX2 protein has been reported to be correlated with colorectal cancers. In this study, we conducted a meta-analysis to evaluate the association of SOX2 with clinical features and prognosis in colorectal cancer.

METHODS

The relevant studies up to March 2019 were searched in Two English databases(PubMed and EMBASE)and two Chinese databases (CNKI and Wanfang database). Pooled ORs or HRs were used to assess the strength of the association between SOX2 and clinical parameters.

RESULTS

14 studies involving 2077 colorectal cancer patients were included in the meta-analysis. Our results revealed there were no associations between SOX2 and gender and age. However, significant positive associations were observed for N categories (OR = 3.02, 95 %CI = 2.11-4.31), advanced stage (OR = 2.85, 95 %CI = 2.00-4.07), poor differentiation (OR = 1.90, 95 %CI = 1.38-2.64), distant metastasis (OR = 4.66, 95 %CI = 2.77-7.85) and poor OS (HR = 1.49, 95 %CI = 1.09-2.03).

CONCLUSION

The results indicated that SOX2 protein may serve as a novel prognostic factor for patients with colorectal cancer.

Sox2: A Regulatory Factor in Tumorigenesis and Metastasis

The transcription factor Sox2 plays an important role in various phases of embryonic development, including cell fate and differentiation. These key regulatory functions are facilitated by binding to specific DNA sequences in combination with partner proteins to exert their effects. Recently, overexpression and gene amplification of Sox2 has been associated with tumor aggression and metastasis in various cancer types, including breast, prostate, lung, ovarian and colon cancer. All the different roles for Sox2 involve complicated regulatory networks consisting of protein-protein and protein-nucleic acid interactions. Their involvement in the EMT modulation is possibly enabled by Wnt/ β-catenin and other signaling pathways. There are number of in vivo models which show Sox2 association with increased cancer aggressiveness, resistance to chemo-radiation therapy and decreased survival rate suggesting Sox2 as a therapeutic target. This review will focus on the different roles for Sox2 in metastasis and tumorigenesis. We will also review the mechanism of action underlying the cooperative Sox2- DNA/partner factors binding where Sox2 can be potentially explored for a therapeutic opportunity to treat cancers.

Combined class I histone deacetylase and mTORC1/C2 inhibition suppresses the initiation and recurrence of oral squamous cell carcinomas by repressing SOX2

Treatment of oral squamous cell carcinoma (OSCC) remains a challenge because of the lack of effective early treatment strategies and high incidence of relapse. Here, we showed that combined 4SC-202 (a novel selective class I HDAC inhibitor) and INK128 (a selective mTORC1/C2 inhibitor) treatment exhibited synergistic effects on inhibiting cell growth, sphere-forming ability, subcutaneous tumor formation and ALDH1⁺ cancer stem cells (CSCs) in OSCC. The initiation of OSCC was significantly inhibited by combined treatment in 4NQO-induced rat model. In addition, upregulated SOX2 was associated with advanced and metastatic tumors in OSCC patients and was responsible for the drug-resistance property of OSCC cells. The inhibitory effect of combined treatment on cell viability and ALDH1⁺ CSCs were attenuated by SOX2 verexpression. Furthermore, combined treatment can effectively overcome chemoresistance and inhibit the growth of recurrent OSCC in vitro and in vivo. Mechanistically, 4SC-202 and INK128 repressed SOX2 expression through miR-429/miR-1181-mediated mRNA degradation and preventing cap-dependent mRNA translation, respectively. These results suggest that combined class I histone deacetylase and mTORC1/C2 inhibition suppresses the carcinogenesis and recurrence of OSCC by repressing SOX2.

IL-8-induced O-GlcNAc modification via GLUT3 and GFAT regulates cancer stem cell-like properties in colon and lung cancer cells

Interleukin-8 (IL-8) is a pro-inflammatory chemokine that is associated with induction of chemotaxis and degranulation of neutrophils. IL-8 is overexpressed in many tumors, including colon and lung cancer, and recent studies demonstrated essential roles for IL-8 in tumor progression within the tumor microenvironment. However, the molecular mechanism underlying the functions of IL-8 in tumor progression is unclear. In this study, we found that IL-8 is overexpressed in colon and lung cancer cells with cancer stem cell (CSC)-like characteristics and is required for CSC properties, including tumor-initiating abilities. These findings suggest that IL-8 plays an essential role in the development of CSCs. We also showed that IL-8 stimulation of colon and lung cancer cells-induced glucose uptake and expressions of glucose transporter 3 (GLUT3) and glucosamine fructose-6-phosphate aminotransferase (GFAT), a regulator of glucose flux to the hexosamine biosynthetic pathway, resulting in enhancement of protein O-GlcNAcylation. We demonstrated that these events are required for the generation and maintenance CSC-like characteristics of colon and lung cancer cells. Moreover, an O-GlcNAcylation inhibitor, OSMI1, reduced CSC number and tumor development in vivo. Together, these results reveal that IL-8-induced O-GlcNAcylation is required for generation and maintenance of CSCs of colon and lung cancer cells and suggests this regulatory pathway as a candidate therapeutic target of CSCs.

SOX2 Promotes Cell Proliferation and Metastasis in Triple Negative Breast Cancer

This study explored the expression, biological function and prognostic role of SOX2 in triple negative breast cancer (TNBC). Quantitative real-time PCR and immunohistochemistry were used to detect the expression of SOX2 in TNBC cell lines and clinical tissues. MTT assay, Transwell assay, flow cytometry and xenograft mouse model were used to assess the biological functions of SOX2. It was found that SOX2 was up-regulated in both TNBC cell lines and clinical tissues. High expression of SOX2 was associated with shorter overall survival and disease free survival. Moreover, inhibition of SOX2 suppressed cell proliferation and invasion, induced cell apoptosis in vitro, and suppressed tumorigenesis and metastasis in vivo. In addition, analysis of TNM stage and lymph nodes infiltration among the 237 TNBC patients by paired χ² test showed that SOX2 was inversely correlated with tumor status, our findings provided evidence that SOX2 acts as a tumor promoter in TNBC and inhibition of SOX2 could be a potential therapeutic strategy for TNBC.