Epithelial-mesenchymal transition with expression of SNAI1-induced chemoresistance in colorectal cancer

Chitosan and hyaluronic acid in colorectal cancer therapy: A review on EMT regulation, metastasis, and overcoming drug resistance

Up to 90% of cancer-related fatalities could be attributed to metastasis. Therefore, understanding the mechanisms that facilitate tumor cell metastasis is beneficial for improving patient survival and results. EMT is considered the main process involved in the invasion and spread of CRC. Essential molecular components like Wnt, TGF-β, and PI3K/Akt play a role in controlling EMT in CRC, frequently triggered by various factors such as Snail, Twist, and ZEB1. These factors affect not only the spread of CRC but also determine the reaction to chemotherapy. The influence of non-coding RNAs, especially miRNAs and lncRNAs, on the regulation of EMT is clear in CRC. Exosomes, involved in cell-to-cell communication, can affect the TME and metastasis of CRC. Pharmacological substances and nanoparticles demonstrate promise as efficient modulators of EMT in CRC. Chitosan and HA are two major carbohydrate polymers with considerable potential in inhibiting CRC. Chitosan and HA can be employed to modify nanoparticles to enhance cargo transport for reducing CRC. Additionally, chitosan and HA-modified nanocarriers, which can be utilized as potential approaches in suppressing EMT and reversing drug resistance in CRC, can inhibit EMT and chemoresistance, crucial components in tumorigenesis.

Computational Elucidation of Hub Genes and Pathways Correlated with the Development of 5-Fluorouracil Resistance in HCT 116 Colorectal Carcinoma Cell Line

Colorectal cancer (CRC) is the third most deadly cancer diagnosed in both men and women. 5-Fluorouracil (5-FU) treatment frequently causes the CRC cells to become chemoresistance, which has a negative impact on prognosis. Using bioinformatic techniques, this work describes important genes and biological pathways linked to 5-FU resistance in CRC cells. In our studies, a 5-FU-resistant HCT 116 cell line exhibiting elevated TYMS was created and validated using various tests. Bioinformatic studies were conducted to determine which differentially expressed genes (DEGs) were responsible for the establishment of 5-FU resistance in the same cell line. After screening 3949 DEGs from the two public datasets (GSE196900 and GSE153412), 471 overlapping DEGs in 5-FU-resistant HCT 116 cells were chosen. These overlapping DEGs were used to build the PPI network, and a major cluster module containing 21 genes was found. Subsequently, using three topological analysis algorithms, 10 hub genes were identified, which included HLA-DRA, HLA-DRB1, CXCR4, MMP9, CDH1, SMAD3, VIM, SYK, ZEB1, and SELL. Their roles were ascertained by utilizing Gene Ontology keywords and pathway enrichment studies. Our results also demonstrated that the miRNA and transcription factors (TFs) that had the strongest connection with the hub genes were hsa-mir-26a-5p, hsa-mir-30a-5p, RELA, and NFKB1. Ultimately, 84 FDA-approved drugs that target those hub genes were found to potentially treat 5-FU resistance CRC. Our research's findings increase our understanding of the fundamental factors that contribute to the prevalence of 5-FU resistance CRC, which could ultimately assist in the identification of valuable malignancy biomarkers and targeted treatment approaches based on key regulatory pathways.

The xenobiotic transporter ABCC4/MRP4 promotes epithelial mesenchymal transition in pancreatic cancer

The xenobiotic transporter ABCC4/MRP4 is highly expressed in pancreatic ductal adenocarcinoma (PDAC) and correlates with a more aggressive phenotype and metastatic propensity. Here, we show that ABCC4 promotes epithelial-mesenchymal transition (EMT) in PDAC, a hallmark process involving the acquisition of mesenchymal traits by epithelial cells, enhanced cell motility, and chemoresistance. Modulation of ABCC4 levels in PANC-1 and BxPC-3 cell lines resulted in the dysregulation of genes present in the EMT signature. Bioinformatic analysis on several cohorts including tumor samples, primary patient-derived cultured cells, patient-derived xenografts, and cell lines, revealed a positive correlation between ABCC4 expression and EMT markers. We also characterized the ABCC4 cistrome and identified four candidate clusters in the distal promoter and intron one that showed differential binding of pro-epithelial FOXA1 and pro-mesenchymal GATA2 transcription factors in low ABCC4-expressing HPAF-II and high ABCC4-expressing PANC-1 xenografts. HPAF-II xenografts showed exclusive binding of FOXA1, and PANC-1 xenografts exclusive binding of GATA2, at ABCC4 clusters, consistent with their low and high EMT phenotype respectively. Our results underscore ABCC4/MRP4 as a valuable prognostic marker and a potential therapeutic target to treat PDAC subtypes with prominent EMT features, such as the basal-like/squamous subtype, characterized by worse prognosis and no effective therapies.

Role of Interleukins in Inflammation-Mediated Tumor Immune Microenvironment Modulation in Colorectal Cancer Pathogenesis

INTRODUCTION

Tumor cells invade and spread through a procedure termed as epithelial-to-mesenchymal cell transition (EMT). EMT is triggered by any alterations in the genes that encode the extracellular matrix (ECM) proteins, the enzymes that break down the ECM, and the activation of the genes that causes the epithelial cell to change into a mesenchymal type. The transcription factors NF-κB, Smads, STAT3, Snail, Zeb, and Twist are activated by inflammatory cytokines, for instance, Tumor Necrosis Factor, Tumor Growth Factors, Interleukin-1, Interleukin-8, and Interleukin-6, which promotes EMT.

MATERIALS

The current piece of work has been reviewed from the literature works published in last 10 years on the role interleukins in inflammation-mediated tumor immune microenvironment modulation in colorectal cancer pathogenesis utilizing the databases like Google Scholar, PubMed, Science Direct.

RESULTS

Recent studies have demonstrated that pathological situations, such as epithelial malignancies, exhibit EMT characteristics, such as the downregulation of epithelial markers and the overexpression of mesenchymal markers. Several growing evidence have also proved its existence in the human colon during the carcinogenesis of colorectal cancer. Most often, persistent inflammation is thought to be one factor contributing to the initiation of human cancers, such as colorectal cancer (CRC). Therefore, according to epidemiologic and clinical research, people with ulcerative colitis and Crohn's disease have a greater probability of developing CRC.

CONCLUSION

A substantial amount of data points to the involvement of the NF-κB system, SMAD/STAT3 signaling cascade, microRNAs, and the Ras-mitogen-activated protein kinase/Snail/Slug in the epithelial-to-mesenchymal transition-mediated development of colorectal malignancies. As a result, EMT is reported to play an active task in the pathogenesis of colorectal cancer, and therapeutic interventions targeting the inflammation-mediated EMT might serve as a novel strategy for treating CRC. The illustration depicts the relationship between interleukins and their receptors as a driver of CRC development and the potential therapeutic targets.

Unraveling the function of epithelial-mesenchymal transition (EMT) in colorectal cancer: Metastasis, therapy response, and revisiting molecular pathways

Colorectal cancer (CRC) is a dangerous form of cancer that affects the gastrointestinal tract. It is a major global health concern, and the aggressive behavior of tumor cells makes it difficult to treat, leading to poor survival rates for patients. One major challenge in treating CRC is the metastasis, or spread, of the cancer, which is a major cause of death. In order to improve the prognosis for patients with CRC, it is necessary to focus on ways to inhibit the cancer's ability to invade and spread. Epithelial-mesenchymal transition (EMT) is a process that is linked to the spread of cancer cells, also known as metastasis. The process transforms epithelial cells into mesenchymal ones, increasing their mobility and ability to invade other tissues. This has been shown to be a key mechanism in the progression of colorectal cancer (CRC), a particularly aggressive form of gastrointestinal cancer. The activation of EMT leads to increases in the spread of CRC cells, and during this process, levels of the protein E-cadherin decrease while levels of N-cadherin and vimentin increase. EMT also contributes to the development of resistance to chemotherapy and radiation therapy in CRC. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a role in regulating EMT in CRC, often through their ability to "sponge" microRNAs. Anti-cancer agents have been shown to suppress EMT and reduce the progression and spread of CRC cells. These findings suggest that targeting EMT or related mechanisms may be a promising approach for treating CRC patients in the clinic.

Current Progress of EMT: A New Direction of Targeted Therapy for Colorectal Cancer with Invasion and Metastasis

Colorectal cancer (CRC) is a common malignant tumor with a high frequency of recurrence and metastasis, which are the major causes of death in patients. The prerequisite for the invasion and metastasis is the strong mobility of CRC cells to transport far away from the original site to the distant organs and tissues, where they settle down and proliferate. It was reported that the epithelial-mesenchymal transition (EMT) is involved in the occurrence and development of various tumors in the entire process of tumor invasion and metastasis. Therefore, as a vital factor for the biological characteristics of tumor cells, EMT markers may serve as prognostic predictors and potential therapeutic targets in CRC. This article mainly reviews the current status of CRC with metastasis, the studies of EMT, the possible relationship of EMT with CRC, as well as the potential targeted therapy.

Identification of hub genes associated with EMT-induced chemoresistance in breast cancer using integrated bioinformatics analysis

Chemoresistance is one of the major challenges in the treatment of breast cancer. Recent evidence suggests that epithelial-to-mesenchymal transition (EMT) plays a critical role in not only metastasis but also in chemoresistance, hence causing tumor relapse. This study aimed to identify the hub genes associated with EMT and chemoresistance in breast cancer affecting patient/clinical survival. Commonly differentially expressed genes (DEGs) during EMT and chemoresistance in breast cancer cells were identified using publicly available datasets, GSE23655, GSE39359, GSE33146 and GSE76540. Hierarchical clustering analysis was utilized to determine the commonly DEGs expression pattern in chemoresistant (CR) breast cancer cells. GSEA revealed that EMT-related genes sets were enriched in the CR samples. Further, we found that EMT-induced breast cancer cells showed overexpression of drug efflux transporters along with resistance to chemotherapeutic drug. Pathway enrichment analysis revealed that the commonly DEGs were enriched in immunological pathways, early endosome, protein dimerization, and proteoglycans in cancer. Further, we identified eight hub genes from the protein-protein interaction (PPI) network. We validated the gene expression levels of the hub genes among TCGA breast cancer samples using UALCAN. Survival analysis for the hub genes was performed using KM plotter, which showed a worse relapse-free survival (RFS) of the hub genes among breast cancer patients. In conclusion, this study identified eight hub genes that play an important role in the pathways underlying EMT-induced chemoresistance in breast cancer and can be used as therapeutic targets after clinical validation.

ECM-Receptor Regulatory Network and Its Prognostic Role in Colorectal Cancer

Interactions of the extracellular matrix (ECM) and cellular receptors constitute one of the crucial pathways involved in colorectal cancer progression and metastasis. With the use of bioinformatics analysis, we comprehensively evaluated the prognostic information concentrated in the genes from this pathway. First, we constructed a ECM-receptor regulatory network by integrating the transcription factor (TF) and 5'-isomiR interaction databases with mRNA/miRNA-seq data from The Cancer Genome Atlas Colon Adenocarcinoma (TCGA-COAD). Notably, one-third of interactions mediated by 5'-isomiRs was represented by noncanonical isomiRs (isomiRs, whose 5'-end sequence did not match with the canonical miRBase version). Then, exhaustive search-based feature selection was used to fit prognostic signatures composed of nodes from the network for overall survival prediction. Two reliable prognostic signatures were identified and validated on the independent The Cancer Genome Atlas Rectum Adenocarcinoma (TCGA-READ) cohort. The first signature was made up by six genes, directly involved in ECM-receptor interaction: AGRN, DAG1, FN1, ITGA5, THBS3, and TNC (concordance index 0.61, logrank test p = 0.0164, 3-years ROC AUC = 0.68). The second hybrid signature was composed of three regulators: hsa-miR-32-5p, NR1H2, and SNAI1 (concordance index 0.64, logrank test p = 0.0229, 3-years ROC AUC = 0.71). While hsa-miR-32-5p exclusively regulated ECM-related genes (COL1A2 and ITGA5), NR1H2 and SNAI1 also targeted other pathways (adhesion, cell cycle, and cell division). Concordant distributions of the respective risk scores across four stages of colorectal cancer and adjacent normal mucosa additionally confirmed reliability of the models.

Mesothelin Expression is Correlated with Chemoresistance in Stage IV Colorectal Cancer

BACKGROUND

Mesothelin (MSLN) is a cell-surface glycoprotein present on mesothelial cells; its expression in several epithelial cancers generally portends an unfavorable prognosis. We investigated MSLN as a surrogate chemopredictive biomarker and examined the impact of MSLN expression in stage IV colorectal cancer (CRC).

METHODS

We recruited 254 patients with CRC who received systemic chemotherapy following primary tumor resection between 2000 and 2019. Resected specimens were immunostained for MSLN and stratified by MSLN expression. The associations of tumor MSLN expression with tumor response in metastatic lesions and survival were evaluated.

RESULTS

Of the 247 patients with stage IV CRC, 41 (16.1%) and 213 (83.9%) had high and low MSLN expression, respectively. Based on the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria, the investigator-assessed objective response rate was 22.0% in the high MSLN expression group and 45.5% in the low MSLN expression group (p = 0.0050). The disease control rates in these groups were 65.9% and 85.9%, respectively (p = 0.00019). In the patients with high MSLN expression, the conversion rate among those with initially unresectable metastases was 0% versus 14% in the patients with low MSLN expression (p = 0.0053). The median overall survival (OS) was 1.5 years (95% confidence interval [CI] 1.1-2.8) in the high MSLN expression group versus 2.6 years (95% CI 2.2-3.0) in the low MSLN expression group. The 3-year OS rates in these groups were 23.5 and 41.5%, respectively (p = 0.0120).

CONCLUSIONS

High MSLN expression is correlated with chemoresistance and poor prognoses in stage IV CRC.

Differential Survival Benefits of 5-Fluorouracil-Based Adjuvant Chemotherapy for Patients With Microsatellite-Stable Stage III Colorectal Cancer According to the Tumor Budding Status: A Retrospective Analysis

BACKGROUND

Recent research has established tumor budding as a prognostic factor and a possible histomorphologic reflection of epithelial-mesenchymal transition in colorectal cancer, highlighting the ability of cancer cells exhibiting epithelial-mesenchymal transition to resist chemotherapy.

OBJECTIVE

This study aimed to investigate the clinical benefits of adjuvant chemotherapy according to the tumor budding status in microsatellite-stable stage III colorectal cancer.

DESIGN

This was a retrospective study of 2 cohorts.

SETTINGS

The study was conducted at the National Defense Medical College in Japan.

PATIENTS

We reviewed 2 data sets of patients with microsatellite-stable stage III colorectal cancer with curatively intended surgery (R0) from 1999 to 2005 (first cohort; n = 203) and 2006 to 2012 (second cohort; n = 346). In both cohorts, 128 and 203 patients received 5-fluorouracil-based adjuvant chemotherapy and 75 and 143 patients did not.

MAIN OUTCOME MEASURES

We assessed the benefits of adjuvant chemotherapy according to the grades of tumor budding based on the cancer-specific survival.

RESULTS

In low-budding tumors, the chemotherapy group exhibited better cancer-specific survival than the surgery-alone group (first cohort, 93.1% vs 65.5%, p = 0.001; second cohort, 94.0% vs 76.0%, p < 0.0001). Conversely, the prognostic difference between the chemotherapy and surgery-alone groups was statistically insignificant in high-budding tumors (first cohort, 59.7% vs 52.4%, p = 0.57; second cohort, 83.1% vs 75.6%, p = 0.19). The multivariate analysis corroborated the benefits of adjuvant chemotherapy in low-budding tumors (first cohort, p = 0.002, HR = 0.28; second cohort, p < 0.0001, HR = 0.23) but not in high-budding tumors.

LIMITATIONS

Postoperative adjuvant chemotherapy and treatments for recurrence were not homogeneous, and the patient backgrounds differed between the chemotherapy and surgery alone groups.

CONCLUSIONS

The high-budding group demonstrated resistance to 5-fluorouracil-based chemotherapy, whereas the low-budding group exhibited significant survival benefits from adjuvant chemotherapy in stage III colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B14. BENEFICIOS DE SUPERVIVENCIA DIFERENCIAL DE LA QUIMIOTERAPIA ADYUVANTE BASADA EN 5-FLUOROURACILO PARA PACIENTES CON CÁNCER COLORRECTAL EN ESTADIO III ESTABLE CON MICROSATÉLITE SEGÚN EL ESTADO DE BROTACIÓN DEL TUMOR: UN ANÁLISIS RETROSPECTIVO:: Investigaciones recientes han establecido la aparición de tumores como un factor pronóstico y una posible reflexión histomorfológica de la transición epitelial-mesenquimatosa en el cáncer colorrectal, destacando la capacidad de las células cancerosas que presentan una transición epitelio-mesenquimática para resistir la quimioterapia.El objetivo de este estudio es investigar los beneficios clínicos de la quimioterapia adyuvante según el estado de brotación del tumor en el cáncer colorrectal en estadio III estable con microsatélite.Este fue un estudio retrospectivo de dos cohortes.El estudio se realizó en la Escuela de Medicina de la Defensa Nacional de Japón.Revisamos dos conjuntos de datos de pacientes con cáncer colorrectal en estadio III estable con microsatélite con cirugía de intención curativa (R0) de 1999 a 2005 (primera cohorte; n = 203) y 2006 a 2012 (segunda cohorte; n = 346). En ambas cohortes, 128 y 203 pacientes recibieron quimioterapia adyuvante basada en 5-fluorouracilo y 75 y 143 pacientes no, respectivamente.Evaluamos los beneficios de la quimioterapia adyuvante de acuerdo con los grados de brotación del tumor en función de la supervivencia específica del cáncer.n los tumores con brotes bajos, el grupo de quimioterapia mostró una mejor supervivencia específica al cáncer que el grupo con cirugía sola (primera cohorte, 93.1% vs. 65.5%, p = 0.001; segunda cohorte, 94.0% vs. 76.0%, p < 0.0001). A la inversa, la diferencia pronóstica entre los grupos de quimioterapia y cirugía sola fue estadísticamente insignificante en los tumores de brotes elevados (primera cohorte, 59.7% vs. 52.4%, p = 0.57; segunda cohorte, 83.1% vs. 75.6%, p = 0.19). El análisis multivariado corroboró los beneficios de la quimioterapia adyuvante en los tumores de brotes bajos (primera cohorte, p = 0,002, índice de riesgo: 0,28; segundo cohorte, p <0,0001, índice de riesgo: 0,23) pero no en los tumores de alto brote.a quimioterapia adyuvante postoperatoria y los tratamientos para la recurrencia no fueron homogéneos, y los antecedentes de los pacientes difirieron entre los grupos de quimioterapia y cirugía sola.El grupo de alto brote demostró resistencia a la quimioterapia basada en 5-fluorouracilo, mientras que el grupo de bajo brote mostró beneficios significativos de supervivencia de la quimioterapia adyuvante en el cáncer colorrectal en estadio III. Vea el Resumen del Video en http://links.lww.com/DCR/B14.

Exosome: Function and Role in Cancer Metastasis and Drug Resistance

As a kind of nanometric lipidic vesicles, exosomes have been presumed to play a leading role in the regulation of tumor microenvironment through exosomes-mediated transfer of proteins and genetic materials. Tumor-derived exosomes are recognized as a critical determinant of the tumor progression. Intriguingly, some current observations have identified that exosomes are essential for several intercellular exchanges of proteins, messenger RNAs, noncoding RNAs (including long noncoding RNAs and microRNAs) as well as to the process of cancer metastasis and drug resistance. Herein, we review the role of exosomes and their molecular cargos in cancer invasion and metastasis, summarize how they interact with antitumor agents, and highlight their translational implications.

A molecular portrait of epithelial-mesenchymal plasticity in prostate cancer associated with clinical outcome

The propensity of cancer cells to transition between epithelial and mesenchymal phenotypic states via the epithelial–mesenchymal transition (EMT) program can regulate metastatic processes, cancer progression, and treatment resistance. Transcriptional investigations using reversible models of EMT, revealed the mesenchymal-to-epithelial reverting transition (MErT) to be enriched in clinical samples of metastatic castrate resistant prostate cancer (mCRPC). From this enrichment, a metastasis-derived gene signature was identified that predicted more rapid cancer relapse and reduced survival across multiple human carcinoma types. Additionally, the transcriptional profile of MErT is not a simple mirror image of EMT as tumour cells retain a transcriptional “memory” following a reversible EMT. This memory was also enriched in mCRPC samples. Cumulatively, our studies reveal the transcriptional profile of epithelial–mesenchymal plasticity and highlight the unique transcriptional properties of MErT. Furthermore, our findings provide evidence to support the association of epithelial plasticity with poor clinical outcomes in multiple human carcinoma types.

CircRBMS3 promotes gastric cancer tumorigenesis by regulating miR-153-SNAI1 axis

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Mounting evidence showed that circular RNAs (circRNAs) play critical roles in human malignancy. However, the knowledge about circRNAs in GC is still unclear. In the current study, high throughput microarray assay showed that circRBMS3 was upregulated in GC tissues, which was further confirmed by quantitative reverse transcription polymerase chain reaction. Correlation analysis revealed that high circRBMS3 expression was associated with advanced TNM stage, depth of invasion, and lymph-node metastasis. Kaplan-Meier analysis indicated that GC patients with high circRBMS3 expression have a poor overall survival (OS). Function assays showed that circRBMS3 silencing reduced GC cells proliferation and invasion in vitro, and inhibited the tumor growth in vivo. Mechanistically, we found that miR-153 could act as a target of circRBMS3. Subsequently, we showed that circRBMS3 promoted snail family zinc finger 1 (SNAI1) expression via inhibiting miR-153 in GC cells. Collectively, these results suggested that circRBMS3 promoted GC cells proliferation and invasion via regulating miR-153/SNAI1 axis.

Novel biomarkers for patient stratification in colorectal cancer: A review of definitions, emerging concepts, and data

Colorectal cancer (CRC) treatment has become more personalised, incorporating a combination of the individual patient risk assessment, gene testing, and chemotherapy with surgery for optimal care. The improvement of staging with high-resolution imaging has allowed more selective treatments, optimising survival outcomes. The next step is to identify biomarkers that can inform clinicians of expected prognosis and offer the most beneficial treatment, while reducing unnecessary morbidity for the patient. The search for biomarkers in CRC has been of significant interest, with questions remaining on their impact and applicability. The study of biomarkers can be broadly divided into metabolic, molecular, microRNA, epithelial-to-mesenchymal-transition (EMT), and imaging classes. Although numerous molecules have claimed to impact prognosis and treatment, their clinical application has been limited. Furthermore, routine testing of prognostic markers with no demonstrable influence on response to treatment is a questionable practice, as it increases cost and can adversely affect expectations of treatment. In this review we focus on recent developments and emerging biomarkers with potential utility for clinical translation in CRC. We examine and critically appraise novel imaging and molecular-based approaches; evaluate the promising array of microRNAs, analyze metabolic profiles, and highlight key findings for biomarker potential in the EMT pathway.

FBXW7 deletion contributes to lung tumor development and confers resistance to gefitinib therapy

Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is an effective treatment for non-small-cell lung cancer (NSCLC) with EGFR activating mutations, but inevitably, the clinical efficacy is impeded by the emergence of acquired resistance. The tumor suppressor gene FBXW7 modulates chemosensitivity in various human cancers. However, its role in EGFR-TKI therapy in NSCLC has not been well studied. Here, we demonstrate that the mice with deficient Fbxw7 have greater susceptibility to urethane-induced lung tumor development. Through analysis of The Cancer Genome Atlas data, we show that deletion of FBXW7 occurs in 30.9% of lung adenocarcinomas and 63.5% of lung squamous cell carcinomas, which significantly leads to decrease in FBXW7 mRNA expression. The reduction in FBXW7 mRNA level is associated with poor overall survival in lung cancer patients. FBXW7 knockdown dramatically promotes epithelial-mesenchymal transition, migration, and invasion in NSCLC cells. Moreover, with silenced FBXW7, EGFR-TKI-sensitive cells become resistant to gefitinib, which is reversed by the mammalian target of rapamycin inhibitor, rapamycin. Furthermore, xenograft mouse model studies show that FBXW7 knockdown enhances tumorigenesis and resistance to gefitinib. Combination of gefitinib with rapamycin treatment suppresses tumor formation of gefitinib-resistant (GR) FBXW7-knockdown cells. In conclusion, our findings suggest that loss of FBXW7 promotes NSCLC progression as well as gefitinib resistance and combination of gefitinib and rapamycin may provide an effective therapy for GR NSCLC.

Predictive value of inflammatory indexes on the chemotherapeutic response in patients with unresectable lung cancer: A retrospective study

Chemotherapy is widely administered to patients with advanced lung cancer; however, data regarding chemotherapeutic sensitivity are limited. The present study aimed to investigate the predictive value of inflammatory indexes for chemotherapeutic efficacy in advanced lung cancer. Patients with stage III and IV unresectable lung cancer that were treated with first-line chemotherapy between January 2007 and December 2011 were retrospectively identified, and chemotherapeutic response was evaluated following 2 or 3 chemotherapy cycles. Prior to chemotherapy, hematologic data and clinicopathological parameters were collected using electronic medical records. The associations between the main inflammatory indexes [which included the pretreatment neutrophil count (PNC), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR)] and the chemotherapeutic efficacy, as well as the prognostic value of the indexes, were analyzed. According to the receiver operating characteristic curve, PLR failed to reach diagnostic accuracy for overall chemotherapeutic response. PNC and NLR were each classified into two groups according to the cut-off values (4.635×10⁹/l for PNC and 2.443 ×10⁹/l for NLR). The overall response rate was significantly higher in the low PNC [odds ratio, 3.261; 95% confidence interval (CI), 2.102-5.060; P<0.001, vs. high PNC] and low NLR groups (odds ratio, 1.596; 95% CI, 1.037-2.454; P=0.033, vs. high NLR). Univariate analyses showed that the high PNC (HR, 1.487) and high NLR groups (HR, 1.288) were associated with poor progression-free survival (PFS); however, NLR was considered statistically insignificant in multivariate analysis. In summary, high PNC and NLR values are associated with chemoresistance and an unfavorable prognosis, with the present study demonstrating that PNC has increased sensitivity when compared with other inflammatory indexes in predicting chemotherapeutic efficacy. Therefore, PNC has the potential to be used as a reliable and suitable predictor to stratify a high risk of chemoresistance in patients with stage III and IV unresectable lung cancer.

Propofol Reversed Hypoxia-Induced Docetaxel Resistance in Prostate Cancer Cells by Preventing Epithelial-Mesenchymal Transition by Inhibiting Hypoxia-Inducible Factor 1α

Prostate cancer is the second most frequently diagnosed cancer worldwide. Hypoxia-induced epithelial–mesenchymal transition (EMT), driven by hypoxia-inducible factor 1α (HIF-1α), is involved in cancer progression and metastasis. The present study was designed to explore the role of propofol in hypoxia-induced resistance of prostate cancer cells to docetaxel. We used the Cell Counting Kit-8 and 5-ethynyl-2′-deoxyuridine incorporation assay to measure cell viability and cell proliferation, respectively, in prostate cancer cell lines. Then, we detected HIF-1α, E-cadherin, and vimentin expression using western blotting. Propofol reversed the hypoxia-induced docetaxel resistance in the prostate cancer cell lines. Propofol not only decreased hypoxia-induced HIF-1α expression, but also reversed hypoxia-induced EMT by suppressing HIF-1α. Furthermore, small interfering RNA–mediated silencing of HIF-1α reversed the hypoxia-induced docetaxel resistance, although there was little change in docetaxel sensitivity between the hypoxia group and propofol group. The induction of hypoxia did not affect E-cadherin and vimentin expression, and under the siRNA knockdown conditions, the effects of propofol were obviated. These data support a role for propofol in regulating EMT in prostate cancer cells. Taken together, our findings demonstrate that propofol plays an important role in hypoxia-induced docetaxel sensitivity and EMT in prostate cancer cells and that it is a potential drug for overcoming drug resistance in prostate cancer cells via HIF-1α suppression.

Salinomycin enhances doxorubicin sensitivity through reversing the epithelial-mesenchymal transition of cholangiocarcinoma cells by regulating ARK5

Chemotherapy response rates in patients with cholangiocarcinoma remain low, primarily due to the development of drug resistance. Epithelial-mesenchymal transition (EMT) of cancer cells is widely accepted to be important for metastasis and progression, but it has also been linked to the development of chemoresistance. Salinomycin (an antibiotic) has shown some potential as a chemotherapeutic agent as it selectively kills cancer stem cells, and has been hypothesized to block the EMT process. In this study, we investigated whether salinomycin could reverse the chemoresistance of cholangiocarcinoma cells to the chemotherapy drug doxorubicin. We found that combined salinomycin with doxorubicin treatment resulted in a significant decrease in cell viability compared with doxorubicin or salinomycin treatment alone in two cholangiocarcinoma cell lines (RBE and Huh-28). The dosages of both drugs that were required to produce a cytotoxic effect decreased, indicating that these two drugs have a synergistic effect. In terms of mechanism, salinomycin reversed doxorubicin-induced EMT of cholangiocarcinoma cells, as shown morphologically and through the detection of EMT markers. Moreover, we showed that salinomycin treatment downregulated the AMP-activated protein kinase family member 5 (ARK5) expression, which regulates the EMT process of cholangiocarcinoma. Our results indicated that salinomycin reversed the EMT process in cholangiocarcinoma cells by inhibiting ARK5 expression and enhanced the chemosensitivity of cholangiocarcinoma cells to doxorubicin. Therefore, a combined treatment of salinomycin with doxorubicin could be used to enhance doxorubicin sensitivity in patients with cholangiocarcinoma.

REOX: Evaluation of the Efficacy of Retreatment With an Oxaliplatin-containing Regimen in Metastatic Colorectal Cancer: A Retrospective Single-center Study

BACKGROUND

Treatment of metastatic colorectal adenocarcinoma (mCRC) has evolved, and survival is over 30 months in contemporary trials. Nevertheless, there is a paucity of effective regimes after the first or second-line treatment. Thus, reexposure to previously used drugs has become a treatment strategy for some patients. We aimed to evaluate the efficacy of retreatment with an oxaliplatin-containing regimen in mCRC and correlate this with clinicopathologic features.

PATIENTS AND METHODS

We retrospectively analyzed 83 patients with mCRC who underwent reexposure to oxaliplatin (REOX). REOX was defined as a second trial of an oxaliplatin-containing regimen after a previous failure. Primary endpoint was time to treatment failure (TTF).

RESULTS

The median age was 53.5 years, and the female/male ratio was 51.8%/48.2%. The site of the primary tumor was colon (67.5%) and rectal (32.5%). KRAS was mutated in 39.8%. Liver-limited metastasis was found in 19.3% of patients. The main regimen was 5-fluorouracil, levoleucovorin, and oxaliplatin (mFOLFOX6) (84.3%). Bevacizumab and cetuximab were used in 42.2% and 6% of patients, respectively. REOX was used in the third and fourth lines in 48.2% and 25.3% of patients, respectively. The median TTF after REOX was 6.04 months. Overall survival (OS) was 10.04 months. Disease control (complete response + partial response + stable disease) was observed in 56.6%, whereas 42.2% had progressive disease. Partial response + complete response to previous oxaliplatin was predictive of prolonged OS. Patients who attained disease control had better median OS compared with those with progressive disease (14.5 vs. 6.24 months; P < .0001).

CONCLUSION

In the setting of heavily pretreated patients with mCRC, REOX was an effective treatment, with mTTF of 6.04 months in our cohort. Selection of patients with the longest time since previous oxaliplatin can translate in better outcome. Further studies should be conducted to confirm our data.

Serum and tissue markers in colorectal cancer: State of art

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade, the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e. bevacizumab, cetuximab, panitumab, aflibercept and regorafenib), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Molecular studies have recently widened the opportunity for testing new possible markers, but actually, only few markers can be recommended for practical use in clinic. In the next future, the hope is to have a complete panel of clinical biomarkers to use in every setting of CRC disease, and at the same time: 1) to receive information about prognostic significance by their expression and 2) to be oriented in the choice of the adequate treatment. Moreover, molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumors may have different long-term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of serum and tissue markers according to the recently published English literature. This paper is an extension of the article "Biological and clinical markers in colorectal cancer: state of art" by Cappellani A published in Jan 2010.

Deregulation of the miR-222-ABCG2 regulatory module in tongue squamous cell carcinoma contributes to chemoresistance and enhanced migratory/invasive potential

Chemoresistance is often associated with other clinical characteristics such as enhanced migratory/invasive potential. However, the correlation and underlying molecular mechanisms remain unclear. The aim of this study was to elucidate the function of the miR-222-ABCG2 pathway in the correlation between cisplatin (DDP) resistance and enhanced cell migration/invasion in tongue squamous cell carcinoma (TSCC). Using TSCC cell lines and primary cultures from TSCC cases, we first confirmed the correlation among DDP resistance (measured by IC50 values and ABCG2/ERCC1 expression), migratory/invasive potential (assessed by migration/invasion assays) and miR-222 expression. In TSCC cells, siRNA-mediated ABCG2 knockdown led to enhanced DDP responsiveness and reduced migratory/invasive potential, whereas ABCG2 overexpression induced DDP resistance and enhanced cell migration/invasion. Luciferase assays revealed that ABCG2 is a direct target of miR-222. In addition to reducing cell migration/invasion, functional analyses in TSCC cells indicated that miR-222 can reduce expression of the ABCG2 gene and enhance DDP responsiveness. However, co-transfection with ABCG2 cDNA restored both DDP resistance and migration/invasion. Moreover, miR-222 mimics and ABCG2 siRNA inhibited tumor growth and lung metastasis in vivo. Thus, our results verified that DDP resistance is correlated with enhanced migratory/invasive potential in TSCC. ABCG2 is a direct target of miR-222,and deregulation of the miR-222-ABCG2 regulatory module in TSCC contributes to both DDP resistance and enhanced migratory/invasive potential.

Exosomes secreted from human colon cancer cells influence the adhesion of neighboring metastatic cells: Role of microRNA-210

Cancer-secreted exosomes influence tumor microenvironment and support cancer growth and metastasis. MiR-210 is frequently up-regulated in colorectal cancer tissues and correlates with metastatic disease. We investigated whether exosomes are actively released by HCT-8 colon cancer cells, the role of exosomal miR-210 in the cross-talk between primary cancer cells and neighboring metastatic cells and its contribution in regulating epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). After 7 d of culture, a subpopulation of viable HCT-8 cells detached the monolayer and started to grow in suspension, suggesting anoikis resistance and a metastatic potential. The expression of key proteins of EMT revealed that these cells were E-cadherin negative and vimentin positive further confirming their metastatic phenotype and the acquisition of anoikis resistance. Metastatic cells, in the presence of adherently growing HCT-8, continued to grow in suspension whereas only if seeded in cell-free wells, were able to adhere again and to form E-cadherin positive and vimentin negative new colonies, suggesting the occurrence of MET. The chemosensitivity to 5 fluorouracil and to FOLFOX-like treatment of metastatic cells was significantly diminished compared to adherent HCT-8 cells. Of note, adherent new colonies undergoing MET, were insensitive to both chemotherapeutic strategies. Electron microscopy analysis demonstrated that adherently growing HCT-8, actually secreted exosomes and that exosomes in turn were taken up by metastatic cells. When exosomes secreted by adherently growing HCT-8 were administered to metastatic cells, MET was significantly inhibited. miR-210 was significantly upregulated in exosomes compared to its intracellular levels in adherently growing HCT-8 cells and correlated to anoikis resistance and EMT markers. Exosomes containing miR-210 might be considered as EMT promoting signals that preserve the local cancer-growth permissive milieu and also guide metastatic cells to free, new sites of dissemination.

CYLD downregulates Livin and synergistically improves gemcitabine chemosensitivity and decreases migratory/invasive potential in bladder cancer: the effect is autophagy-associated

Although GC (gemcitabine and cisplatin) chemotherapy remains an effective method for treating bladder cancer (BCa), chemoresistance is a major obstacle in chemotherapy. In this study, we determined whether gemcitabine resistance correlates with migratory/invasive potential in BCa and whether this relationship is regulated by the cylindromatosis (CYLD)-Livin module. First, we independently investigated the correlation of CYLD/Livin and gemcitabine resistance with the potential for tumor migration and invasiveness. Second, we found that co-transfected CYLD and Livin dramatically improved sensitivity to gemcitabine chemotherapy and decreased migration/invasion potential. Next, we determined that CYLD may regulate Livin by the NF-κB-dependent pathway. We also found that CYLD overexpression and Livin knockdown might improve gemcitabine chemosensitivity by decreasing autophagy and increasing apoptosis in BCa cells. Finally, the effects of CYLD-Livin on tumor growth in vivo were evaluated. Our study demonstrates that CYLD-Livin might represent a potential therapeutic for chemoresistant BCa.

SERPINI1 regulates epithelial-mesenchymal transition in an orthotopic implantation model of colorectal cancer

An increasingly accepted concept is that the progression of colorectal cancer is accompanied by epithelial-mesenchymal transition (EMT). In our study, in order to characterize the properties of EMT in 16 colorectal cancer cell lines, the cells were first orthotopically implanted into nude mice, and the tumors in vivo, as well as cells cultured in vitro, were immunostained for EMT markers. The immunostaining revealed that seven of the cells had an epithelial phenotype with a high expression of E-cadherin, whereas other cells showed opposite patterns, such as a high expression of vimentin (CX-1, COLO205, CloneA, HCT116, and SW48). Among the cells expressing vimentin, some expressed vimentin in the orthotopic tumors but not in the cultured cells (SW480, SW620, and COLO320). We evaluated these findings in combination with microarray analyses, and selected five genes: CHST11, SERPINI1, AGR2, FBP1, and FOXA1. Next, we downregulated the expression of SERPINI1 with siRNA in the cells, the results of which showed reverse-EMT changes at the protein level and in the cellular morphology. Along with immunohistochemical analyses, we confirmed the effect of the intracellular and secreted SERPINI1 protein of SW620 cells, which supported the importance of SERPINI1 in EMT. The development of therapeutic strategies targeting EMT is ongoing, including methods targeting the transforming growth factor-β signaling pathway as well as the Wnt pathway. SERPINI1 is an important regulator of EMT. Our findings help to elucidate the signaling pathways of EMT, hopefully clarifying therapeutic pathways as well.

Inhibition of cathepsin proteases attenuates migration and sensitizes aggressive N-Myc amplified human neuroblastoma cells to doxorubicin

Neuroblastoma arises from the sympathetic nervous system and accounts for 15% of childhood cancer mortality. Amplification of the oncogene N-Myc is reported to occur in more than 20% of patients. While N-Myc amplification status strongly correlates with higher tumour aggression and resistance to treatment, the role of N-Myc in the aggressive progression of the disease is poorly understood. N-Myc being a transcription factor can modulate the secretion of key proteins that may play a pivotal role in tumorigenesis. Characterising the soluble secreted proteins or secretome will aid in understanding their role in the tumour microenvironment, such as promoting cancer cell invasion and resistance to treatment. The aim of this study is to characterise the secretome of human malignant neuroblastoma SK-N-BE2 (N-Myc amplified, more aggressive) and SH-SY5Y (N-Myc non-amplified, less aggressive) cells. Conditioned media from SK-N-BE2 and SH-SY5Y cell lines were subjected to proteomics analysis. We report a catalogue of 894 proteins identified in the secretome isolated from the two neuroblastoma cell lines, SK-N-BE2 and SH-SY5Y. Functional enrichment analysis using FunRich software identified enhanced secretion of proteins implicated in cysteine peptidase activity in the aggressive N-Myc amplified SK-N-BE2 secretome compared to the less tumorigenic SH-SY5Y cells. Protein-protein interaction-based network analysis highlighted the enrichment of cathepsin and epithelial-to-mesenchymal transition sub-networks. For the first time, inhibition of cathepsins by inhibitors sensitized the resistant SK-N-BE2 cells to doxorubicin as well as decreased its migratory potential. The dataset of secretome proteins of N-Myc amplified (more aggressive) and non-amplified (less aggressive) neuroblastoma cells represent the first inventory of neuroblastoma secretome. The study also highlights the prominent role of cathepsins in the N-Myc amplified neuroblastoma pathogenesis. As N-Myc amplification correlates with aggressive neuroblastoma and chemotherapy-based treatment failure, co-treatment with cathepsin inhibitors might be a better avenue for disease management.

A new role for the PI3K/Akt signaling pathway in the epithelial-mesenchymal transition

Tumor metastasis is not only a sign of disease severity but also a major factor causing treatment failure and cancer-related death. Therefore, studies on the molecular mechanisms of tumor metastasis are critical for the development of treatments and for the improvement of survival. The epithelial-mesenchymal transition (EMT) is an orderly, polygenic biological process that plays an important role in tumor cell invasion, metastasis and chemoresistance. The complex, multi-step process of EMT involves multiple regulatory mechanisms. Specifically, the PI3K/Akt signaling pathway can affect the EMT in a variety of ways to influence tumor aggressiveness. A better understanding of the regulatory mechanisms related to the EMT can provide a theoretical basis for the early prediction of tumor progression as well as targeted therapy.

A literature mining-based approach for identification of cellular pathways associated with chemoresistance in cancer

Chemoresistance is a major obstacle to the successful treatment of many human cancer types. Increasing evidence has revealed that chemoresistance involves many genes and multiple complex biological mechanisms including cancer stem cells, drug efflux mechanism, autophagy and epithelial-mesenchymal transition. Many studies have been conducted to investigate the possible molecular mechanisms of chemoresistance. However, understanding of the biological mechanisms in chemoresistance still remains limited. We surveyed the literature on chemoresistance-related genes and pathways of multiple cancer types. We then used a curated pathway database to investigate significant chemoresistance-related biological pathways. In addition, to investigate the importance of chemoresistance-related markers in protein-protein interaction networks identified using the curated database, we used a gene-ranking algorithm designed based on a graph-based scoring function in our previous study. Our comprehensive survey and analysis provide a systems biology-based overview of the underlying mechanisms of chemoresistance.

Laminin β3 expression as a prognostic factor and a predictive marker of chemoresistance in colorectal cancer

OBJECTIVE

Laminin-332, a marker of epithelial-mesenchymal transition, is composed of a heterotrimer of α3, β3 and γ2 chains that regulates cell adhesion and migration. This study aimed to disclose the respective clinical significance of laminin β3 immunoexpression in colorectal cancer as a prognostic factor and a predictive marker of chemoresistance.

METHODS

Tissue specimens from 323 Stage II and 232 Stage III colorectal cancer patients who underwent curative resection were assessed using laminin β3 immunostaining.

RESULTS

Among Stage III colorectal cancer patients, comparisons of 5-year disease-free survival rates revealed a poorer prognosis for the laminin β3-high group than for the laminin β3-low group (52.3 vs. 70.7%, P = 0.038), while there was no significant difference among Stage II patients. Among laminin β3-low Stage III patients, those who received adjuvant chemotherapy showed marginally better disease-free survival than those who did not receive it (75.8 vs. 62.8%; P = 0.096). Furthermore, multivariate analysis corroborated a distinct benefit of adjuvant chemotherapy in laminin β3-low patients (P = 0.035; hazard risk ratio = 1.66). Analyses of the laminin β3-high group, however, failed to show significance.

CONCLUSIONS

Laminin β3 chain immunoreactivity was a poor prognostic factor for Stage III colorectal cancer patients, and laminin β3-high patients of Stage III colorectal cancer derived no survival benefit from adjuvant chemotherapy.

Epithelial-mesenchymal transition in colorectal cancer metastasis: A system review

Tumor metastasis is a multi-step process by which tumor cells disseminate from their primary site and form secondary tumors at a distant site. And metastasis is the major cause of death in the vast majority of cancer patients. However, the mechanisms underlying each step remain obscure. In the past decade, a developmental program epithelial-to-mesenchymal transition (EMT) has been increasingly recognized to play pivotal and intricate roles in promoting carcinoma invasion and metastasis. The EMT process is very complex and controlled by various families of transcriptional regulators through different signaling pathways. In this system review, we focus on the molecular network of the EMT program and its malignant phenotypes associated with metastasis in colorectal cancer (CRC), including cancer stem cells, tumor budding, circulating tumor cells and drug resistance. A better understanding of the molecular regulation of the dynamic EMT program during tumor metastasis will help to provide much-needed therapeutic interventions to target this program when treating metastatic CRC.

Overexpression of SIX1 is an independent prognostic marker in stage I-III colorectal cancer

Epithelial-to-mesenchymal transition (EMT) contributes significantly to tumor progression and metastasis. The assessment of EMT-associated transcription factors could be a promising approach to identify biomarkers and potential therapeutic targets in colorectal cancer. In our study, we focused on the transcription factor "Sine oculis homeobox" (SIX) 1, which is a member of the superfamily of the homeobox genes and has been described to promote EMT in different types of tumors. Immunohistochemistry against SIX1 was performed on colorectal mucosa, adenomas, carcinomas-in situ and primary adenocarcinomas. An expression score was developed and subsequently assessed for its prognostic value in two independent cohorts. Cohort 1 consisted of 128 patients with stage I-III colorectal cancer; cohort 2 included 817 patients with stage I-III colorectal cancer who had participated in the DACHS study. HCT-116 cells were transfected with SIX1 plasmids and subjected to migration and colony formation assays. The expression of SIX1 increases gradually from mucosa to colorectal adenocarcinomas (p > 0.0001). Univariate and multivariate analyses reveal that high expression of SIX1 is associated with decreased overall survival (cohort 1: HR: 4.01, CI: 1.20-14.07, p = 0.025; cohort 2: HR: 1.43, CI: 1.014-2.02, p = 0.047). Overexpression of SIX1 induces a more mesenchymal-like phenotype in HCT-116 cells and enhances tumor migration. High expression of SIX1 is an independent prognostic marker in colorectal cancer. It might be a promising biomarker to stratify patients into different risk groups. Moreover, targeting SIX1 might be a novel therapeutic approach in patients with colorectal cancer.

Slug-dependent upregulation of L1CAM is responsible for the increased invasion potential of pancreatic cancer cells following long-term 5-FU treatment

Background

Pancreatic adenocarcinoma is a lethal disease with 5-year survival of less than 5%. 5-fluorouracil (5-FU) is a principal first-line therapy, but treatment only extends survival modestly and is seldom curative. Drug resistance and disease recurrence is typical and there is a pressing need to overcome this. To investigate acquired 5-FU resistance in pancreatic adenocarcinoma, we established chemoresistant monoclonal cell lines from the Panc 03.27 cell line by long-term exposure to increasing doses of 5-FU.

Results

5-FU-resistant cell lines exhibited increased expression of markers associated with multidrug resistance explaining their reduced sensitivity to 5-FU. In addition, 5-FU-resistant cell lines showed alterations typical for an epithelial-to-mesenchymal transition (EMT), including upregulation of mesenchymal markers and increased invasiveness. Microarray analysis revealed the L1CAM pathway as one of the most upregulated pathways in the chemoresistant clones, and a significant upregulation of L1CAM was seen on the RNA and protein level. In pancreatic cancer, expression of L1CAM is associated with a chemoresistant and migratory phenotype. Using esiRNA targeting L1CAM, or by blocking the extracellular part of L1CAM with antibodies, we show that the increased invasiveness observed in the chemoresistant cells functionally depends on L1CAM. Using esiRNA targeting β-catenin and/or Slug, we demonstrate that in the chemoresistant cell lines, L1CAM expression depends on Slug rather than β-catenin.

Conclusion

Our findings establish Slug-induced L1CAM expression as a mediator of a chemoresistant and migratory phenotype in pancreatic adenocarcinoma cells.

Establishment and characterization of models of chemotherapy resistance in colorectal cancer: Towards a predictive signature of chemoresistance

Current standard treatments for metastatic colorectal cancer (CRC) are based on combination regimens with one of the two chemotherapeutic drugs, irinotecan or oxaliplatin. However, drug resistance frequently limits the clinical efficacy of these therapies. In order to gain new insights into mechanisms associated with chemoresistance, and departing from three distinct CRC cell models, we generated a panel of human colorectal cancer cell lines with acquired resistance to either oxaliplatin or irinotecan. We characterized the resistant cell line variants with regards to their drug resistance profile and transcriptome, and matched our results with datasets generated from relevant clinical material to derive putative resistance biomarkers. We found that the chemoresistant cell line variants had distinctive irinotecan- or oxaliplatin-specific resistance profiles, with non-reciprocal cross-resistance. Furthermore, we could identify several new, as well as some previously described, drug resistance-associated genes for each resistant cell line variant. Each chemoresistant cell line variant acquired a unique set of changes that may represent distinct functional subtypes of chemotherapy resistance. In addition, and given the potential implications for selection of subsequent treatment, we also performed an exploratory analysis, in relevant patient cohorts, of the predictive value of each of the specific genes identified in our cellular models.

The biological and clinical importance of epithelial-mesenchymal transition in circulating tumor cells

Movement of tumor cells from a primary tumor to a nonadjacent or distant site is a contiguous and complex process. Among the multiple natural cellular programs that promote initiation and progression of tumor metastasis, epithelial-mesenchymal transition (EMT) may play a key role in the ultimate generation of a metastatic foci. Acquisition of the EMT phenotype by tumor cells not only increases their migration and invasion potentials, thereby facilitating their ability to infiltrate blood vessels and to produce circulating tumor cells (CTCs), but also promotes survival of CTCs in the bloodstream and their ability to extravasate out of the circulatory system and invade proximal tissues. In organs distal to the primary tumor, the phenotypic switching mechanism of mesenchymal-epithelial transition (MET) enables CTCs to grow and colonize, enhancing the likelihood of establishing metastasis. In addition, CTCs that have undergone EMT attain increased resistance to chemotherapy and targeted therapy. CTCs with the EMT phenotype have become recognized as an active source of metastases, and targeting EMT/MET processes during the individual steps of tumor metastasis represents a promising new approach for alleviating cancer metastasis and recurrence. In this article, we focus on the biological and clinical importance of EMT and/or MET in CTCs during the individual steps of tumor metastasis, summarizing the recent findings of the regulatory roles played by EMT and/or MET in the generation, survival, and recolonization of CTCs and discussing the EMT-targeting strategies developed for tumor diagnosis as well as their potential for management of metastatic malignant diseases.

FBW7 upregulation enhances cisplatin cytotoxicity in non- small cell lung cancer cells

INTRODUCTION

Lung cancer is extremely harmful to human health and has one of the highest worldwide incidences of all malignant tumors. Approximately 80% of lung cancers are classified as non-small cell lung cancers (NSCLCs). Cisplatin-based multidrug chemotherapy regimen is standard for such lesions, but drug resistance is an increasing problem. F-box/WD repeat-containing protein 7 (FBW7) is a member of the F-box protein family that regulates cell cycle progression, and cell growth and differentiation. FBW7 also functions as a tumor suppressor.

METHODS

We used cell viability assays, Western blotting, and immunofluorescence combined with siRNA interference or plasmid transfection to investigate the underlying mechanism of cisplatin resistance in NSCLC cells.

RESULTS

We found that FBW7 upregulation significantly increased cisplatin chemosensitivity and that cells expressing low levels of FBW7, such as NCI-H1299 cells, have a mesenchymal phenotype. Furthermore, siRNA-mediated silencing or plasmid-mediated upregulation of FBW7 resulted in altered epithelial-mesenchymal transition (EMT) patterns in NSCLC cells. These data support a role for FBW7 in regulating the EMT in NSCLC cells.

CONCLUSION

FBW7 is a potential drug target for combating drug resistance and regulating the EMT in NSCLC cells.

PDGFRα and β play critical roles in mediating Foxq1-driven breast cancer stemness and chemoresistance

Many epithelial-mesenchymal transition (EMT)-promoting transcription factors have been implicated in tumorigenesis and metastasis as well as chemoresistance of cancer. However, the underlying mechanisms mediating these processes are unclear. Here, we report that Foxq1, a forkhead box-containing transcription factor and EMT-inducing gene, promotes stemness traits and chemoresistance in mammary epithelial cells. Using an expression profiling assay, we identified Twist1, Zeb2, and PDGFRα and β as Foxq1 downstream targets. We further show that PDGFRα and β can be directly regulated by Foxq1 or indirectly regulated through the Foxq1/Twist1 axis. Knockdown of both PDGFRα and β results in more significant effects on reversing Foxq1-promoted oncogenesis in vitro and in vivo than knockdown of either PDGFRα or β alone. In addition, PDGFRβ is a more potent mediator of Foxq1-promoted stemness traits than PDGFRα. Finally, pharmacologic inhibition or gene silencing of PDGFRs sensitizes mammary epithelial cells to chemotherapeutic agents in vitro and in vivo. These findings collectively implicate PDGFRs as critical mediators of breast cancer oncogenesis and chemoresistance driven by Foxq1, with potential implications for developing novel therapeutic combinations to treat breast cancer.

The therapeutic potential of targeting the epithelial-mesenchymal transition in cancer

INTRODUCTION

The process of epithelial-to-mesenchymal transition (EMT) has long been advocated as a process during tumor progression and the acquisition of metastatic potential of human cancers. EMT has also been linked with resistance to cancer therapies.

AREAS COVERED

Basic research has provided evidence connecting EMT to increased invasion, angiogenesis and metastasis of cancer cells. A number of signaling pathways such as notch, wnt, hedgehog and PI3K-AKT, and various other individual factors therein, have been intricately connected to the onset of EMT. Here, we provide latest updates on the evidences that further highlight an association between various signaling pathways and EMT, with a focus on therapeutic targets that may have the potential to reverse EMT.

EXPERT OPINION

Our understanding of EMT and its underlying causes is rapidly evolving and a number of putative targets have been identified. It is crucial, now than ever before, to design novel translational and clinical studies for the benefit of advanced stage cancer patients with metastatic disease.

[Epithelial-mesenchymal transition and tumor drug resistance]

Resistance to antineoplastic drugs is a common problem in cancer treatments. Epithelial-mesenchymal transition (EMT), which plays an important role in the process of drug resistance, may provide opportunity to solve this problem. This article reviews the characteristics of EMT, relationship between EMT and drug resistance, mechanism of EMT in tumor drug resistance in details.

Regulation of the protein stability of EMT transcription factors

The epithelial to mesenchymal transition (EMT) consists of a rapid change of cell phenotype, characterized by the loss of epithelial characteristics and the acquisition of a more invasive phenotype. Transcription factors regulating EMT (Snail, Twist and Zeb) are extremely labile proteins, rapidly degraded by the proteasome system. In this review we analyze the current mechanisms controlling degradation of EMT transcription factors, focusing on the role of new E3 ubiquitin-ligases involved in EMT. We also summarize the regulation of the stability of these EMT transcription factors, specially observed in different stress conditions, such as hypoxia, chemotherapeutic drugs, oxidative stress or γ-irradiation.

Snail expression and outcome in T1 high-grade and T2 bladder cancer: a retrospective immunohistochemical analysis

Background

Neoadjuvant chemotherapy has been shown to have benefit in T1 high-grade or T2 bladder cancer. However, neoadjuvant chemotherapy fails in some patients. Careful patient selection for neoadjuvant chemotherapy is therefore needed. Several reports show that Snail is associated with resistance to chemotherapy. We hypothesized that Snail expression could predict survival in T1 high-grade and T2 bladder cancer patients treated with neoadjuvant chemotherapy.

Methods

The participants were 44 patients with T1 high-grade and T2 bladder cancer receiving neoadjuvant chemotherapy. Immunohistochemical analysis was used to determine Snail expression in specimens of bladder cancer obtained by transurethral resection before neoadjuvant chemotherapy. The relationships between Snail expression and patients’ outcomes were analyzed.

Results

Snail expression was positive in 15 of the 44 patients (34.1%) and negative in 29 (65.9%). Disease-free survival was significantly shorter for the Snail-positive group than for the Snail-negative group (p = 0.014). In addition, disease-specific survival was also significantly shorter for the Snail-positive group than for the Snail-negative group (p = 0.039). In multivariate analysis, Snail expression level was identified as an independent prognostic factor for disease-specific survival (p = 0.020).

Conclusions

The results indicate that Snail expression may predict poor outcome in T1 high-grade and T2 bladder cancer patients treated with neoadjuvant chemotherapy.

Sorcin silencing inhibits epithelial-to-mesenchymal transition and suppresses breast cancer metastasis in vivo

Sorcin, a 22-kDa calcium-binding protein, renders cancer cells resistant to chemotherapeutic agents, thus playing an important role in multidrug resistance. As there is a clear association between drug resistance and an aggressive phenotype, we asked whether sorcin affects also the motility, invasion, and stem cell characteristics of cancer cells. We have used both RNA interference (transient and stable expression of hairpins) and a lentiviral expression vector to experimentally modulate sorcin expression in a variety of cells. We demonstrate that sorcin depletion in MDA-MB-231 breast cancer cells reduces the pool of CD44(+)/CD24(-) and ALDH1(high) cancer stem cells (CSCs) as well as mammosphere-forming capacity. We also observe that sorcin regulates epithelial-mesenchymal transition and CSCs partly through E-cadherin and vascular endothelial growth factor expression. This leads to the acquisition of an epithelial-like phenotype, attenuating epithelial-mesenchymal transition and suppression of metastases in nude mice. The sorcin-depleted phenotype can also be reproduced in lung adenocarcinoma A549 cells and lung fibrosarcoma HT1080 cells. In addition, overexpression of sorcin in MCF7 cells, which have low endogenous sorcin expression levels, increases their migration and invasion in vitro. This offers the rationale for the development of therapeutic strategies down-regulating sorcin expression for the treatment of cancer.

Epithelial-mesenchymal plasticity in carcinoma metastasis

Tumor metastasis is a multistep process by which tumor cells disseminate from their primary site and form secondary tumors at a distant site. Metastasis occurs through a series of steps: local invasion, intravasation, transport, extravasation, and colonization. A developmental program termed epithelial-mesenchymal transition (EMT) has been shown to play a critical role in promoting metastasis in epithelium-derived carcinoma. Recent experimental and clinical studies have improved our knowledge of this dynamic program and implicated EMT and its reverse program, mesenchymal-epithelial transition (MET), in the metastatic process. Here, we review the functional requirement of EMT and/or MET during the individual steps of tumor metastasis and discuss the potential of targeting this program when treating metastatic diseases.

Knockdown of dual specificity phosphatase 4 enhances the chemosensitivity of MCF-7 and MCF-7/ADR breast cancer cells to doxorubicin

BACKGROUND

Breast cancer is the major cause of cancer-related deaths in females world-wide. Doxorubicin-based therapy has limited efficacy in breast cancer due to drug resistance, which has been shown to be associated with the epithelial-to-mesenchymal transition (EMT). However, the molecular mechanisms linking the EMT and drug resistance in breast cancer cells remain unclear. Dual specificity phosphatase 4 (DUSP4), a member of the dual specificity phosphatase family, is associated with cellular proliferation and differentiation; however, its role in breast cancer progression is controversial.

METHODS

We used cell viability assays, Western blotting and immunofluorescent staining, combined with siRNA interference, to evaluate chemoresistance and the EMT in MCF-7 and adriamycin-resistant MCF-7/ADR breast cancer cells, and investigate the underlying mechanisms.

RESULTS

Knockdown of DUSP4 significantly increased the chemosensitivity of MCF-7 and MCF-7/ADR breast cancer cells to doxorubicin, and MCF-7/ADR cells which expressed high levels of DUSP4 had a mesenchymal phenotype. Furthermore, knockdown of DUSP4 reversed the EMT in MCF-7/ADR cells, as demonstrated by upregulation of epithelial biomarkers and downregulation of mesenchymal biomarkers, and also increased the chemosensitivity of MCF-7/ADR cells to doxorubicin.

CONCLUSIONS

DUSP4 might represent a potential drug target for inhibiting drug resistance and regulating the process of the EMT during the treatment of breast cancer.

Epithelial-to-mesenchymal transition is involved in BCNU resistance in human glioma cells

Chemotherapy has been considered as an effective treatment for malignant glioma; however, it becomes increasingly ineffective with tumor progression. Epithelial-to-mesenchymal transition (EMT) is a process whereby cells acquire morphologic and molecular alterations that facilitate tumor metastasis and progression. Emerging evidence associates chemoresistance with the acquisition of EMT in cancer. However, it is not clear whether this phenomenon is involved in glioma. We used the previously established human glioma cell lines SWOZ1, SWOZ2 and SWOZ2-BCNU to assess cellular morphology, molecular changes, migration and invasion. We found that BCNU-resistant cells showed multiple drug resistance and phenotypic changes consistent with EMT, including spindle-shaped morphology and enhanced pseudopodia formation. Decreased expression of the epithelial adhesion molecule E-cadherin and increased expression of the mesenchymal marker vimentin were observed in BCNU-resistant SWOZ1 and SWOZ2-BCNU cells compared to SWOZ2 cells. Migratory and metastatic potentials were markedly enhanced in SWOZ1 and SWOZ2-BCNU cells compared to SWOZ2 cells. These data suggest that there is a possible link between drug resistance and EMT induction in glioma cells. Gaining further insight into the mechanisms underlying chemoresistance and EMT may enable the restoration of chemosensitivity or suppression of metastasis.

Roles Each of Snail, Yin Yang 1 and RKIP in the Regulation of Tumor Cells Chemo-immuno-resistance to Apoptosis

The current anti-cancer therapeutic armamentarium consists of surgery, chemotherapy, radiation, hormonal therapy, immunotherapy, and combinations thereof. Initial treatments usually result in objective clinical responses with prolongation of overall survival (OS) and progression-free survival (PFS) in a large subset of the treated patients. However, at the onset, there is a subset of patients who does not respond and another subset that initially responded but experiences relapses and recurrences. These latter subsets of patients develop a state of cross-resistance to a variety of unrelated therapies. Therefore, there is an urgent need to first unravel the underlying mechanisms of resistance and associated gene products that regulate the cross-resistance. Such gene products are potential therapeutic targets as well as potential prognostic/diagnostic biomarkers. In this context, we have identified three interrelated gene products involved in resistance, namely, Snail, YY1, and RKIP that are components of the dysregulated NF-κB/Snail/YY1/RKIP loop in many cancers. In this review, we will discuss the roles each of Snail, YY1 and RKIP in the regulation of tumor cell resistance to chemo and immunotherapies. Since these same gene products have also been shown to be involved in the regulation of the EMT phenotype and metastasis, we suggest that targeting any of these three gene products can simultaneously inhibit tumor cell resistance and metastasis.

Epithelial mesenchymal transition in colorectal cancer: Seminal role in promoting disease progression and resistance to neoadjuvant therapy

BACKGROUND

Epithelial mesenchymal transition (EMT) may be physiological as part of embryological development, or pathological as part of cancer development. It is one of the key initiating events in the metastatic cascade. EMT has profound effects on tumour cell invasiveness, proliferation and motility. In the present article we aimed to review the potential role of EMT as a process to explain colorectal cancer progression and resistance to neoadjuvant therapy.

METHODS

Extensive literature searches were performed in Pubmed, EMBASE and Google Scholar databases to identify relevant articles published before March 2012.

RESULTS

There is adequate evidence to support the complex upstream signalling alterations needed for EMT to occur in colorectal cancers. Changes of EMT are likely to be found at the tumour invasive front: the deepest, growing tumour margin. Loss of E-cadherin at the cell membrane causes loss of cellular integrity, with subsequent migration of malignant cells and tumour budding. These processes are associated with metastases and recurrence of colorectal cancer. There is early evidence from a limited number of studies that resistance to neoadjuvant therapy in colorectal cancer is associated with changes of EMT. However, there is a lack of supporting evidence originating from human colorectal cancer tissues.

CONCLUSIONS

Emerging evidence demonstrates that development of EMT in colorectal cancer leads to an aggressive phenotype that may promote metastatic spread, and augment treatment resistance during neoadjuvant therapy. A clearer understanding of the processes and role of EMT in colorectal cancer may also highlight novel therapeutic strategies.

Defining new criteria for selection of cell-based intestinal models using publicly available databases

Background

The criteria for choosing relevant cell lines among a vast panel of available intestinal-derived lines exhibiting a wide range of functional properties are still ill-defined. The objective of this study was, therefore, to establish objective criteria for choosing relevant cell lines to assess their appropriateness as tumor models as well as for drug absorption studies.

Results

We made use of publicly available expression signatures and cell based functional assays to delineate differences between various intestinal colon carcinoma cell lines and normal intestinal epithelium. We have compared a panel of intestinal cell lines with patient-derived normal and tumor epithelium and classified them according to traits relating to oncogenic pathway activity, epithelial-mesenchymal transition (EMT) and stemness, migratory properties, proliferative activity, transporter expression profiles and chemosensitivity. For example, SW480 represent an EMT-high, migratory phenotype and scored highest in terms of signatures associated to worse overall survival and higher risk of recurrence based on patient derived databases. On the other hand, differentiated HT29 and T84 cells showed gene expression patterns closest to tumor bulk derived cells. Regarding drug absorption, we confirmed that differentiated Caco-2 cells are the model of choice for active uptake studies in the small intestine. Regarding chemosensitivity we were unable to confirm a recently proposed association of chemo-resistance with EMT traits. However, a novel signature was identified through mining of NCI60 GI50 values that allowed to rank the panel of intestinal cell lines according to their drug responsiveness to commonly used chemotherapeutics.

Conclusions

This study presents a straightforward strategy to exploit publicly available gene expression data to guide the choice of cell-based models. While this approach does not overcome the major limitations of such models, introducing a rank order of selected features may allow selecting model cell lines that are more adapted and pertinent to the addressed biological question.

C4.4A is associated with tumor budding and epithelial-mesenchymal transition of colorectal cancer

C4.4A is a glycolipid-anchored membrane protein expressed in several human malignancies. The aim of this study was to explore the association between C4.4A expression at the invasion front of colorectal cancer (CRC) and tumor budding, a putative hallmark of cell invasion of CRC. Advanced CRCs (T2-4, n = 126) had a budding count of 3.66 ± 5.66, which was significantly higher than that of T1 early CRCs (1.75 ± 2.78, n = 87). C4.4A-positive CRC specimens showed a larger budding cell number than C4.4A-negative CRC specimens in T1 CRCs, and especially advanced CRCs (9.45 ± 5.83 vs 1.60 ± 3.93). Furthermore, we found a correlation between the percentage of C4.4A-positive cases and budding count in advanced CRC. Multivariate analysis for patients' survival showed that C4.4A was superior to tumor budding as a prognostic factor. With siRNA treatment, C4.4A levels were associated with cell invasion, but not with proliferation, in HCT116 and DLD1 cell lines. An immunohistochemical study in a subset of CRCs showed no relationship between C4.4A and Ki-67 proliferation marker. In vitro assays using HCT116 indicated that C4.4A levels correlated well with epithelial-mesenchymal transition (EMT) with regard to cell morphology and alterations of EMT markers including E-cadherin, vimentin, and partially N-cadherin. We also found that C4.4A expression was significantly associated with loss of E-cadherin and gain of β-catenin in clinical CRC tissue samples. These findings suggest that a tight association between C4.4A and tumor budding may, in part, be due to C4.4A promoting EMT at the invasive front of CRC.