L1CAM expression in endometrial carcinomas is regulated by usage of two different promoter regions

KLF12 interacts with TRIM27 to affect cisplatin resistance and cancer metastasis in esophageal squamous cell carcinoma by regulating L1CAM expression

Krüppel-like factor 12 (KLF12) has been characterized as a transcriptional repressor, and previous studies have unveiled its roles in angiogenesis, neural tube defect, and natural killer (NK) cell proliferation. However, the contribution of KLF12 to cancer treatment remains undefined. Here, we show that KLF12 is downregulated in various cancer types, and KLF12 downregulation promotes cisplatin resistance and cancer metastasis in esophageal squamous cell carcinoma (ESCC). Mechanistically, KLF12 binds to the promoters of L1 Cell Adhesion Molecule (L1CAM) and represses its expression. Depletion of L1CAM abrogates cisplatin resistance and cancer metastasis caused by KLF12 loss. Moreover, the E3 ubiquitin ligase tripartite motif-containing 27 (TRIM27) binds to the N-terminal region of KLF12 and ubiquitinates KLF12 at K326 via K33-linked polyubiquitination. Notably, TRIM27 depletion enhances the transcriptional activity of KLF12 and consequently inhibits L1CAM expression. Overall, our study elucidated a novel regulatory mechanism involving TRIM27, KLF12 and L1CAM, which plays a substantial role in cisplatin resistance and cancer metastasis in ESCC. Targeting these genes could be a promising approach for ESCC treatment.

Evaluation of prognostic potential of β-catenin and L1CAM expression according to endometrial cancer risk group

OBJECTIVE

We investigate the prognostic role of β-catenin and L1 neuronal cell-adhesion molecule (L1CAM) according to risk groups in endometrial carcinomas (EC).

METHODS

A total of 335 EC patients were classified according to the Proactive Molecular Risk Classifier for Endometrial Cancer. We evaluated the expression of ß-catenin and L1CAM using immunohistochemistry, and their association with clinicopathological characteristics and survival.

RESULTS

The expressions of β-catenin and L1CAM were observed in 10.4% of all patients, respectively, and showed mutually exclusive pattern. While β-catenin expression was associated with endometrioid histology (p = 0.035) and low tumor grade (p = 0.045), L1CAM expression was associated with non-endometrioid histology (p < 0.001), high tumor grade (p < 0.001), lymphovascular space invasion (p = 0.006), and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (p = 0.001). β-catenin expression was most frequent in the no specific molecular (NSMP) group (26/35, 74.3%), followed by the DNA polymerase-ε-mutated (POLE-mut) (6/35, 17.1%), and mismatch repair-deficiency (dMMR) (3/35, 8.6%). L1CAM expression was most frequent in the p53-abnormal group (22/35, 62.9%), followed by the NSMP (6/35, 17.1%), dMMR (4/35, 11.4%), and POLE-mut (3/35, 8.6%). Although both markers did not show statistical significance in multivariate analysis for both progression-free survival (PFS) and overall survival in entire cohort, β-catenin positivity was identified as the sole factor associated with worse PFS in the high-intermediate risk subgroup (p = 0.001).

CONCLUSION

The expression of nuclear β-catenin may serve as a potential biomarker for predicting recurrence and guiding therapeutic strategies in high-intermediate risk EC patients.

Tryptophan hydroxylase 1 drives glioma progression by modulating the serotonin/L1CAM/NF-κB signaling pathway

Background

Glioma is one of the main causes of cancer-related mortality worldwide and is associated with high heterogeneity. However, the key players determining the fate of glioma remain obscure. In the present study, we shed light on tumor metabolism and aimed to investigate the role of tryptophan hydroxylase 1 (TPH-1) in the advancement of glioma.

Method

Herein, the levels of TPH-1 expression in glioma tissues were evaluated using The Cancer Genome Atlas (TCGA) database. Further, the proliferative characteristics and migration ability of TPH-1 overexpressing LN229/T98G cells were evaluated. Additionally, we performed a cytotoxicity analysis using temozolomide (TMZ) in these cells. We also examined the tumor growth and survival time in a mouse model of glioma treated with chemotherapeutic agents and a TPH-1 inhibitor.

Results

The results of both clinical and experimental data showed that excess TPH-1 expression resulted in sustained glioma progression and a dismal overall survival in these patients. Mechanistically, TPH-1 increased the production of serotonin in glioma cells. The elevated serotonin levels then augmented the NF-κB signaling pathway through the upregulation of the L1-cell adhesion molecule (L1CAM), thereby contributing to cellular proliferation, invasive migration, and drug resistance. In vivo experiments demonstrated potent antitumor effects, which benefited further from the synergistic combination of TMZ and LX-1031.

Conclusion

Taken together, these data suggested that TPH-1 facilitated cellular proliferation, migration, and chemoresistance in glioma through the serotonin/L1CAM/NF-κB pathway. By demonstrating the link of amino acid metabolic enzymes with tumor development, our findings may provide a potentially viable target for therapeutic manipulation aimed at eradicating glioma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09569-2.

High L1CAM expression predicts poor prognosis of patients with endometrial cancer: A systematic review and meta-analysis

BACKGROUD

Previous studies have reported that the levels of L1 cell adhesion molecule (L1CAM) indicate poor prognosis of patients with various solid tumors. However, the prognostic significance of L1CAM in endometrial cancer has remained controversial. Herein, we conducted a systematic review and meta-analysis to evaluate the prognostic value of L1CAM in endometrial cancer.

METHODS

All studies related to the association between L1CAM expression and clinical characteristics of endometrial cancer were identified by searching the PubMed, MEDLINE, EMBASE, and Web of Science databases. Primary outcomes of the meta-analysis were the hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS). Secondary outcomes were odds ratios (ORs) for clinicopathological characteristics. Publication bias and sensitivity analysis were conducted to ensure reliability of the results.

RESULTS

Overall, 17 studies encompassing 7146 patients were eligible for the meta-analysis. Results showed L1CAM overexpression to be significantly associated with decreased overall survival (HR = 2.87, 95% CI; 1.81-4.55, P < .001) and disease-free survival (HR = 3.32, 95% CI; 1.99-5.55, P < .001) in patients with endometrial cancer. High L1CAM expression was also related to adverse clinicopathological characteristics.

CONCLUSION

This systematic review demonstrated that high L1CAM expression is correlated with poor survival outcomes and adverse clinicopathological parameters in patients with endometrial cancer.

miR-193a-3p inhibition of the Slug activator PAK4 suppresses non-small cell lung cancer aggressiveness via the p53/Slug/L1CAM pathway

L1 cell adhesion molecule (L1CAM) promotes invasiveness and metastasis in non-small cell lung cancer (NSCLC) cells and is upregulated by the p53-regulated transcription factor Slug. p21-activated kinase 4 (PAK4) directly phosphorylates Slug, resulting in pro-malignant Slug stabilization. We hypothesized that microRNA-based negative regulation of PAK4 would reduce L1CAM-induced NSCLC aggressiveness via destabilizing Slug. We found that elevated L1CAM expression was tightly correlated with p53 loss-of-function and reduced NSCLC patient survival. L1CAM suppression reduced NSCLC cell migration and invasiveness in vitro as well as tumor formation and distal metastasis in vivo. Mechanistically, p53 restricts L1CAM expression through the β-catenin/Slug pathway, with levels of β-catenin and Slug positively correlating with L1CAM expression in NSCLC tumors. The microRNA miR-193a-3p directly targets PAK4 and suppresses downstream p-Slug and L1CAM expression. Silencing PAK4, Slug, and L1CAM mirrored miR-193a-3p's effects upon the migration and invasiveness of NSCLC cells in vitro. Decreased miR-193a-3p levels correlated with elevated PAK4, p-Slug, and L1CAM levels in NSCLC tumors. Our findings support a model of miR-193a-3p as a suppressor of metastatic disease progression in NSCLC via modulation of the p53/Slug/L1CAM pathway.

Non-redundant functions of EMT transcription factors

Epithelial-mesenchymal transition (EMT) is a crucial embryonic programme that is executed by various EMT transcription factors (EMT-TFs) and is aberrantly activated in cancer and other diseases. However, the causal role of EMT and EMT-TFs in different disease processes, especially cancer and metastasis, continues to be debated. In this Review, we identify and describe specific, non-redundant functions of the different EMT-TFs and discuss the reasons that may underlie disputes about EMT in cancer.

L1CAM further stratifies endometrial carcinoma patients with no specific molecular risk profile

Background

The newly developed Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) has consistently been shown to be prognostically significant in endometrial carcinomas (EC). Recently, we and others have demonstrated L1 cell-adhesion molecule (L1CAM) to be a significant indicator of high-risk disease in EC. In the current study, it was our aim to determine the prognostic significance of aberrant L1CAM expression in ProMisE subgroups in a large, single centre, population-based EC cohort.

Methods

ProMisE (POLE; MMR-D; p53 wt/NSMP; p53 abn) classification results from a cohort of 452 EC were available for analysis. L1CAM expression was studied by immunohistochemistry on whole slides. Correlations between clinicopathological data and survival were calculated.

Results

Expression of L1CAM was most frequent in p53 abnormal tumours (80%). L1CAM status was predictive of worse outcome among tumours with no specific molecular profile (p53 wt/NSMP) (p < 0.0001). Among p53 wt/NSMP EC, L1CAM remained a significant prognosticator for disease-specific survival after multivariate analysis (p = 0.035).

Conclusion

L1CAM status was able to significantly stratify risk among tumours of the large p53 wt/NSMP ProMisE subgroup of EC. Furthermore, our study confirms a highly significant correlation between mutation-type p53 immunostaining and abnormal L1CAM expression in EC.

Prognostic significance of L1 cell adhesion molecule in cancer patients: A systematic review and meta-analysis

The L1 cell adhesion molecule (L1CAM) extensively participates in nervous system development and the malignant progression of human tumours. The prognostic value of L1CAM for the survival of patients with solid tumours remains controversial. The present meta-analysis was thus performed to highlight the relationship between L1CAM expression and prognosis in cancer patients. Relevant publications were identified after searching several widely used databases, including PubMed, EMBASE and the ISI Web of Science. A fixed-effect or random-effect meta-analytical model was employed to correlate L1CAM expression with different outcome measures in both entire tumours and stratified subgroups. 37 studies in total with 8552 patients were eligible for the final analysis. Combined hazard ratios (HRs) and 95% confidence intervals (CIs) suggested that high L1CAM expression had an unfavourable impact on overall survival (HR=2.06, 95%CI 1.65-2.57, P<0.001), disease-specific survival (HR=2.45, 95%CI 1.48-4.05, P<0.001), disease-free survival (HR=2.42, 95%CI 1.4-4.19, P=0.002) and progression-free survival/recurrence-free survival (HR=2.07, 95%CI 1.41-3.05, P<0.001). Subgroup analysis revealed a similar correlation in most tumour types. Overall, L1CAM might be an effective poor prognostic factor for patients with various tumour types.

Fine Tuning of Canonical Wnt Stimulation Enhances Differentiation of Pluripotent Stem Cells Independent of β-Catenin-Mediated T-Cell Factor Signaling

The canonical Wnt/β-catenin pathway is crucial for early embryonic patterning, tissue homeostasis, and regeneration. While canonical Wnt/β-catenin stimulation has been used extensively to modulate pluripotency and differentiation of pluripotent stem cells (PSCs), the mechanism of these two seemingly opposing roles has not been fully characterized and is currently largely attributed to activation of nuclear Wnt target genes. Here, we show that low levels of Wnt stimulation via ectopic expression of Wnt1 or administration of glycogen synthase kinase-3 inhibitor CHIR99021 significantly increases PSC differentiation into neurons, cardiomyocytes and early endodermal intermediates. Our data indicate that enhanced differentiation outcomes are not mediated through activation of traditional Wnt target genes but by β-catenin's secondary role as a binding partner of membrane bound cadherins ultimately leading to the activation of developmental genes. In summary, fine-tuning of Wnt signaling to subthreshold levels for detectable nuclear β-catenin function appears to act as a switch to enhance differentiation of PSCs into multiple lineages. Our observations highlight a mechanism by which Wnt/β-catenin signaling can achieve dosage dependent dual roles in regulating self-renewal and differentiation. Stem Cells 2018;36:822-833.

Expression of neural cell adhesion molecule L1 (CD171) in neuroectodermal and other tumors: An immunohistochemical study of 5155 tumors and critical evaluation of CD171 prognostic value in gastrointestinal stromal tumors

The neural cell adhesion molecule L1 (CD171) is a multidomain type 1 membrane glycoprotein of the immunoglobulin superfamily important in the nervous system development, kidney morphogenesis, and maintenance of the immune system. Recent studies reported CD171 expression being associated with adverse clinical outcome in different types of cancer and there has been a growing interest in targeting this cell membrane molecule on neoplastic cells by chimeric antigen receptor redirected T lymphocytes or specific antibodies. Nevertheless, conflicting results regarding the prognostic value of CD171 expression in renal cell carcinomas and gastrointestinal stromal tumors were published. In this study, CD171 expression was immunohistochemically analyzed in 5155 epithelial, mesenchymal, melanocytic, and lymphohematopoietic tumors to assess its utility in diagnostic pathology and to pinpoint potential targets for CD171-targeting therapy. A newly developed anti-CD171 rabbit monoclonal antibody, clone 014, was selected from the panel of commercially available CD171 antibodies. Immunohistochemistry was performed using Leica Bond Max automation and multitumor blocks containing up to 60 tumor samples. CD171 was constitutively and strongly expressed in neuroectodermal tumors such as schwannoma, neuroblastoma, and paraganglioma, whereas other mesenchymal tumors including schwannoma mimics showed only rarely CD171 positivity. Frequent CD171-expression was also detected in ovarian serous carcinoma, malignant mesothelioma, and testicular embryonal carcinoma. CD171 immunohistochemistry may have some role in immunophenotypic differential diagnosis of neurogenic tumors and pinpointing potential candidates for anti-CD171 therapy. Though, because of its rare expression and lack of predictive value, CD171 is neither a diagnostic nor prognostic marker for gastrointestinal stromal tumors.

Evaluating L1CAM expression in human endometrial cancer using qRT-PCR

Background

Management of endometrial carcinoma (EC) still needs improvement of risk assessment. Recently, L1CAM immunohistochemical (IHC) evaluation showed a unique value to predict the outcome of early EC. However IHC results are often conflicting for lack of inter-laboratory standardisation.

Methods

Here, as a proof of concept and to increase reproducibility we assayed eighty-two EC and 26 normal endometrium samples for L1CAM expression (L1CAM^EXP) via qRT-PCR. The IHC evaluation was performed in 50 cancer samples. Moreover, we aimed to substantiate the in-vitro findings of L1CAM regulation through its promoter methylation (L1CAM^MET), miR-34a expression and miR-34a promoter methylation. DNA methylation was assessed with MethyLight PCR technique.

Results

High overall concordant results between IHC and RT-PCR evaluations were found. L1CAM^EXP was detected in 11% of cancer specimens. These positive cancers exhibited a worse DFS (p=0.032) and OS (p=0.016) in a multivariate COX-regression model. L1CAM^EXP predicted distant failure (p=0.007) and L1CAM^MET predicted risk-reduction of lymph-node involvement (p=0.005). Inverse correlations between L1CAM^EXP and L1CAM^MET (p=0.004) and between L1CAM^EXP and miR-34a expression (p=0.002) were found.

Conclusions

In conclusion qRT-PCR analysis is a reliable approach to evaluate L1CAM status in EC and L1CAM^EXP was highly predictive for distant failure and poor outcome, confirming the large IHC-based studies. Interestingly, L1CAM^MET was able to assess the risk of pelvic lymph-node involvement. Especially the latter finding has to be confirmed in larger prospective series.

The L1 adhesion molecule normalizes neuritogenesis in Rett syndrome-derived neural precursor cells

Therapeutic intervention is an important need in ameliorating the severe consequences of Rett Syndrome (RTT), a neurological disorder caused by mutations in the X-linked gene methyl-CpG-binding protein-2 (MeCP2). Following previously observed morphological defects in induced pluripotent stem cell (iPSC)-derived neurons obtained from female RTT patients, we hypothesized that transfection with the L1 cell adhesion molecule (L1) could contribute to normalizing a pathological male cell system bearing a nonsense mutation of MeCP2. We found a decreased expression of L1 in RTT iPSCs-derived neural precursor cells (RTT NPCs) and decreased neuritogenesis. Expression of wild-type MeCP2 in RTTNPCs revealed a positive correlation between the levels of MeCP2 and L1, and normalization of cell survival. Expression of L1 in RTTNPCs enhanced neuritogenesis and soma size. Knock-down of MeCP2 in wild type NPCs reduced neuritogenesis. L1 expression is regulated by the MeCP2 promoter. These results suggest that a deficiency in L1 may partially account for RTT phenotypes.

L1 increases adhesion-mediated proliferation and chemoresistance of retinoblastoma

Retinoblastoma is the most common intraocular cancer in children, affecting 1/20,000 live births. Currently, children with retinoblastoma were treated with chemotherapy using drugs such as carboplatin, vincristine, and etoposide. Unfortunately, if conventional treatment fails, the affected eyes should be removed to prevent extension into adjacent tissues and metastasis. This study is to investigate the roles of L1 in adhesion-mediated proliferation and chemoresistance of retinoblastoma. L1 was differentially expressed in 30 retinoblastoma tissues and 2 retinoblastoma cell lines. Furthermore, the proportions of L1-positive cells in retinoblastoma tumors were negatively linked with the number of Flexner-Wintersteiner rosettes, a characteristic of differentiated retinoblastoma tumors, in each tumor sample. Following in vitro experiments using L1-deleted and -overexpressing cells showed that L1 increased adhesion-mediated proliferation of retinoblastoma cells via regulation of cell cycle-associated proteins with modulation of Akt, extracellular signal-regulated kinase, and p38 pathways. In addition, L1 increased resistance against carboplatin, vincristine, and esoposide through up-regulation of apoptosis- and multidrug resistance-related genes. In vivo tumor formation and chemoresistance were also positively linked with the levels of L1 in an orthotopic transplantation model in mice. In this manner, L1 increases adhesion-mediated proliferation and chemoresistance of retinoblastoma. Targeted therapy to L1 might be effective in the treatment of retinoblastoma tumors, especially which rapidly proliferate and demonstrate resistance to conventional chemotherapeutic drugs.

C1QBP suppresses cell adhesion and metastasis of renal carcinoma cells

Complement component 1q subcomponent binding protein (C1QBP) is a ubiquitously expressed cellular protein and can be upregulated or activated in a variety of malignant tumors, including those from thyroid, colon and breast, but its role remains unclear in renal cell carcinoma (RCC). In this study, C1QBP knockdown in RCC cell influenced expression of multiple genes associated with cell adhesion, among which L1 cell adhesion molecule (L1CAM) was significantly higher upon a reduction of C1QBP. In turn, cell adhesion and invasion abilities were significantly increased with increased metastasis to lung and liver in vivo. C1QBP may regulate RCC cell adhesion and invasion through influencing the p-GSK3/β-Catenin/L1CAM expression. Over all, our study demonstrated that C1QBP could regulate RCC metastasis by regulating the GSK3/β-Catenin/L1CAM signaling pathway.

The sL1CAM in sera of patients with endometrial and ovarian cancers

PURPOSE

L1CAM is a cell adhesion molecule suspected to play an important role in carcinogenesis. The objective of the study was to evaluate the level of soluble L1CAM in the sera of patients with endometrial and ovarian carcinomas and verify the feasibility of the sL1CAM as a marker of these carcinomas.

METHODS

35 endometrial and 18 ovarian cancer patients were enrolled in the study. 43 patients with benign gynecological conditions constituted a control group. The sL1CAM serum level was measured with ELISA test in each patient and it was referred to the data from the surgical staging of the cancers.

RESULTS

The sL1CAM serum level was significantly lower in patients with endometrial cancer than in healthy women and slightly lower in the ovarian cancer group than in the control group. In the endometrial cancer group there was no correlation between sL1CAM concentration and cancer histopathology, stage or grade. sL1CAM concentration positively correlated with ovarian cancer stage and (not significantly) with grade.

CONCLUSIONS

Despite the increasing data about the possible role of L1CAM as a strong prognostic factor of poor outcome in many cancers, we did not find evidence supporting the use of sL1CAM as a marker of endometrial or ovarian cancers.

TWIST1 drives cisplatin resistance and cell survival in an ovarian cancer model, via upregulation of GAS6, L1CAM, and Akt signalling

Epithelial ovarian cancer (EOC) is the most deadly gynaecologic malignancy due to late onset of symptoms and propensity towards drug resistance. Epithelial-mesenchymal transition (EMT) has been linked to the development of chemoresistance in other cancers, yet little is known regarding its role in EOC. In this study, we sought to determine the role of the transcription factor TWIST1, a master regulator of EMT, on cisplatin resistance in an EOC model. We created two Ovcar8-derived cell lines that differed only in their TWIST1 expression. TWIST1 expression led to increased tumour engraftment in mice, as well as cisplatin resistance in vitro. RNA sequencing analysis revealed that TWIST1 expression resulted in upregulation of GAS6 and L1CAM and downregulation of HMGA2. Knockdown studies of these genes demonstrated that loss of GAS6 or L1CAM sensitized cells to cisplatin, but that loss of HMGA2 did not give rise to chemoresistance. TWIST1, in part via GAS6 and L1CAM, led to higher expression and activation of Akt upon cisplatin treatment, and inhibition of Akt activation sensitized cells to cisplatin. These results suggest TWIST1- and EMT-driven increase in Akt activation, and thus tumour cell proliferation, as a potential mechanism of drug resistance in EOC.

Regulation of epithelial-mesenchymal transition in endometrial cancer: connecting PI3K, estrogen signaling, and microRNAs

Endometrial cancer (EC) prognosis is dependent on many factors such as time of diagnosis, histological type, and degree of invasion. Type I EC has a more favorable prognosis as it is less prone to myometrial invasion, which is believed to be the first step in the metastatic cascade. Type II EC displays a more aggressive and motile phenotype, and therefore has a poorer prognosis. Recent work suggests that despite the epithelial nature of Type I and Type II endometrial tumors, both are capable of undergoing an epithelial-mesenchymal transition (EMT), which may facilitate myometrial invasion and metastasis. Activation of the PI3K/Akt pathway has been shown to contribute to EMT through the upregulation of EMT-associated factors. Recent research has also linked estrogen signaling and microRNAs to the regulatory mechanisms that drive EMT in EC. Understanding the intricate relationships between these pathways will provide a better understanding of metastatic progression in EC.

L1CAM is an independent predictor of poor survival in endometrial cancer - An analysis of The Cancer Genome Atlas (TCGA)

BACKGROUND

L1-cell adhesion molecule (L1CAM) was previously reported to carry a poor prognosis in Stage I, low-risk endometrial cancer (EC). We evaluated the role of L1CAM among all stages and histologies in ECs in The Cancer Genome Atlas (TCGA).

METHODS

Clinical information and RNA-Seq expression data were derived from TCGA uterine cancer cohort. Associations between L1CAM expression and clinical factors were tested with linear and logistic regression. Differences in survival between "high" and "low" expression groups (defined by median expression) of L1CAM were compared using Cox regression analysis, with p-values calculated via log-rank test. Kaplan-Meier curves were tested with the log-rank test.

RESULTS

Patient characteristics of 545 primary tumors with RNA-Seq gene expression data were analyzed. Median age was 64years (range 31-90). Stage I, II, III, and IV comprised 62%, 10%, 23%, and 5%, respectively. 75% were endometrioid; 21% serous. Grade 1, 2, and 3 comprised 18%, 22%, and 60%, respectively. Median follow-up was 23.0months. High L1CAM expression was associated with advanced stage (OR 3.2), high grade (OR=6.8), serous histology (OR=16.3), positive cytology (OR=3.5), positive pelvic (OR=21.8) and para-aortic lymph nodes (OR=10.3) (all p≤0.001). High L1CAM was associated with a median overall survival (OS) of 107months, versus not reached for low L1-expressing ECs (HR=3.46, CI 1.97-6.07, p<0.001). On multivariate analysis, L1CAM expression remained an independent prognostic variable in predicting OS in EC.

CONCLUSIONS

L1CAM expression is an independent predictor of poor survival in endometrial cancer, and is associated with advanced stage, high-risk endometrial 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.

Role of miR-34a as a suppressor of L1CAM in endometrial carcinoma

L1CAM promotes cell motility, invasion and metastasis formation in various human cancers and can be considered as a driver of tumor progression. Knowledge about genetic processes leading to the presence of L1CAM in cancers is of considerable importance. Experimentally, L1CAM expression can be achieved by various means. Overexpression of the transcription factor SLUG or treatment of cells with TGF-ß1 can induce or augment L1CAM levels in cancer cells. Likewise, hypomethylation of the L1CAM promoter on the X chromosome correlates with L1CAM expression. However, presently no mechanisms that might control transcriptional activity are known. Here we have identified miR-34a as a suppressor of L1CAM. We observed that L1CAM positive endometrial carcinoma (EC) cell lines HEC1B and SPAC1L lost L1CAM protein and mRNA by treatment with demethylating agents or knock-down of the DNA-methyltransferase-1 (DNMT1). Concomitantly, several miRNAs were up-regulated. Using miRNA profiling, luciferase reporter assays and mutagenesis, we identified miR-34a as a putative binder to the L1CAM-3'UTR. Overexpression of miR-34a in HEC1B cells blocked L1CAM expression and inhibited cell migration. In ECC1 cells (wildtype p53) the activation of p53 caused miR-34a up-regulation and loss of L1CAM expression that was miR-34a dependent. We observed an inverse correlation between L1CAM and miR-34a levels in EC cell lines. In primary tumor sections areas expressing high amounts of L1CAM had less miR-34a expression than those with low L1CAM levels. Our data suggest that miR-34a can regulate L1CAM expression by targeting L1CAM mRNA for degradation. These findings shed new light on the complex regulation of L1CAM in human tumors.

L1CAM is expressed in triple-negative breast cancers and is inversely correlated with androgen receptor

Background

Breast cancer is a heterogeneous disease displaying distinct molecular features and clinical outcome. The molecular profile of triple-negative breast cancers (TNBCs) overlaps with that of basal-like breast cancers that in turn show similarities with high-grade serous ovarian and endometrial carcinoma. L1CAM is an established biomarker for the latter cancers and we showed before that approximately 18% of primary breast cancers are positive for L1CAM and have a bad prognosis. Here we analysed the expression of L1CAM breast cancer subtypes.

Methods

We analyzed mRNA and protein expression data from different breast cancer cohorts for L1CAM, estrogen receptor, progesterone receptor, Her-2 and Androgen receptor (AR) and correlated the data. We performed Western blot analysis on tumor cell lysates and carried out chromatin-immuno-precipitation (CHIP) after AR overexpression.

Results

We find that L1CAM is expressed preferentially though not exclusively in TNBCs. Using the human cancer genome atlas database and two independent breast cancer cohorts we find that L1CAM is inversely correlated with androgen receptor (AR) expression. We found that L1CAM^highAR^low primary breast tumors have the worst clinical outcome. Overexpression of AR in MDA-MB436 breast cancer cells decreased L1CAM expression at the protein and mRNA level and CHIP-analysis revealed binding of AR to the L1CAM promoter region.

Conclusions

These results suggest that L1CAM in breast cancer is under AR control. The data also strongly advocate the use of L1CAM assessment in breast cancer diagnosis. We suggest that L1CAM expression could be causally related to the bad prognosis of TNBCs.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-958) contains supplementary material, which is available to authorized users.

L1 cell adhesion molecule expression is associated with pelvic lymph node metastasis and advanced stage in diabetic patients with endometrial cancer: a matched case control study

Background:

Diabetic patients with endometrial cancer had more lymph node metastasis than non-diabetic patients with endometrial cancer. L1 cell adhesion molecule (L1CAM) could be possibly associated with lymph node metastasis in diabetic patients with endometrial cancer via epithelial-mesenchymal transition. We aimed to investigate the association between L1CAM expression and lymph node metastasis in diabetic patients with endometrial cancer.

Methods:

We conducted a matched case control study of 68 endometrial cancer patients who comprise each 34 diabetic and non-diabetic patients. L1CAM expression was evaluated by immunohistochemistry using fresh formalin-fixed paraffin-embedded tissue block of the patients. The association between L1CAM expression and pelvic lymph node metastasis was assessed according to the presence of diabetes.

Results:

Of the 68 patients, 13 (19.1%) were positive for L1CAM immunostaining. Positive rate of L1CAM expression in diabetic endometrial cancer patients was similar to that in non-diabetic endometrial cancer patients (14.7% vs. 23.5%, P = 0.355). Tumor recurred more frequently in patients with positive L1CAM expression than those with negative L1CAM expression (33.3% vs. 1.6%, P = 0.019). However, we failed to find any significant association between L1CAM expression and lymph node metastasis. Only for the diabetic patients (n = 34), patients with pelvic lymph node metastasis had more L1CAM expression than those without lymph node metastasis (50.0% vs. 3.6%, P = 0.035). Advanced stage was the only risk factor for recurrence that showed a significant association with L1CAM expression for the diabetic endometrial cancer patients (P = 0.006), as well as all the enrolled patients (P = 0.014).

Conclusion:

L1CAM expression is associated with pelvic lymph node metastasis and advanced stage in diabetic patients with endometrial cancer.

miR-21-3p is a positive regulator of L1CAM in several human carcinomas

Expression of L1 cell adhesion molecule (L1CAM) occurs frequently in human cancers and is associated with poor prognosis in cancers such as ovarian, endometrial, breast, renal cell carcinoma and pancreatic ductal adenocarcinoma. L1CAM promotes cell motility, invasion, chemoresistance and metastasis formation. Elucidating genetic processes involved in the expression of L1CAM in cancers is of considerable importance. Transcription factors such as SLUG, β-catenin/TCF-LEF, PAX8 and VHL have been implicated in the re-activation of L1CAM in various types of cancers. There is increasing evidence that micro-RNAs can also have strong effects on gene expression. Here we have identified miR-21-3p as a positive regulator of L1CAM expression. Over-expression of miR-21-3p (miR-21*) but not the complementary sequence miR-21-5p (miR-21) could strongly augment L1CAM expression in renal, endometrial and ovarian carcinoma derived cell lines by an unknown mechanism involving transcriptional activation of the L1CAM gene. In patient cohorts from renal, endometrial and ovarian cancers we observed a strong positive correlation of L1CAM and miR-21-3p expressions. Although L1CAM alone was a reliable marker for overall and disease free survival, the combination of L1CAM and miR-21-3p expressions strongly enhanced the predictive power. Our findings shed new light on the complex regulation of L1CAM in cancers and advocate the use of L1CAM/miR-21-3p for diagnostic application.

Epigenetic regulation of L1CAM in endometrial carcinoma: comparison to cancer-testis (CT-X) antigens

Background

L1CAM was originally identified as an adhesion molecule involved in neural development. In many human carcinomas L1CAM is over-expressed and is associated with a bad prognosis. We previously reported that L1CAM was absent in the vast majority of endometrioid endometrial carcinomas (ECs) (type 1) but was strongly expressed in the more aggressive serous and clear-cell ECs (termed type 2). The differential regulation of L1CAM in ECs is not well understood. Recent evidence suggests that it can be regulated by epigenetic mechanisms. Here we investigated the role of DNA-methylation of the L1CAM promoter for expression. We also studied the relationship to cancer testis (CT-X) antigens that co-localize with L1CAM on chromosome Xq28, a region that is often activated in human tumors.

Methods

We used EC cell lines and primary tumor tissues for our analysis. For expression analysis we employed RT-PCR and Western blotting. DNA-Methylation of the L1CAM promoter was determined after bisulfite conversation and DNA sequencing. Tumor tissues were examined by immunohistochemical (IHC) staining.

Results

We demonstrate that the treatment of L1CAM low/negative expressing EC cell lines with 5^′-Azacytidine (5-AzaC) or knock-down of DNMT1 (DNA methyltransferase 1) as well as the HDAC (histone deacetylase) inhibitor Trichostatin A (TSA) up-regulated L1CAM at the mRNA and protein level. The L1CAM gene has two promoter regions with two distinct CpG islands. We observed that the expression of L1CAM correlated with hypermethylation in promoter 1 and 5-AzaC treatment affected the DNA-methylation pattern in this region. The CT-X antigens NY-ESO-1, MAGE-A3 and MAGE-A4 were also strongly up-regulated by 5-AzaC or knock-down of DNMT1 but did not respond to treatment with TSA. Primary EC tumor tissues showed a variable methylation pattern of the L1CAM promoter. No striking differences in promoter methylation were observed between tumor areas with L1CAM expression and those without expression.

Conclusions

L1CAM expression correlated with methylation of the L1CAM promoter in EC cell lines. In negative cell lines L1CAM expression is up-regulated by epigenetic mechanism. Although genes localized on Xq28 are often re-expressed by human tumors, L1CAM and CT-X antigens show distinct regulation in response to HADC inhibitors and 5-AzaC.

CD24 controls Src/STAT3 activity in human tumors

CD24 is a glycosyl-phosphatidylinositol-anchored membrane protein that is frequently over-expressed in a variety of human carcinomas and is correlated with poor prognosis. In cancer cell lines, changes of CD24 expression can alter several cellular properties in vitro and tumor growth in vivo. However, little is known about how CD24 mediates these effects. Here we have analyzed the functional consequences of CD24 knock-down or over-expression in human cancer cell lines. Depletion of CD24 reduced cell proliferation and adhesion, enhanced apoptosis, and regulated the expression of various genes some of which were identified as STAT3 target genes. Loss of CD24 reduced STAT3 and FAK phosphorylation. Diminished STAT3 activity was confirmed by specific reporter assays. We found that reduced STAT3 activity after CD24 knock-down was accompanied by altered Src phosphorylation. Silencing of Src, similar to CD24, targeted the expression of prototype STAT3-regulated genes. Likewise, the over-expression of CD24 augmented Src-Y416 phosphorylation, the recruitment of Src into lipid rafts and the expression of STAT3-dependent target genes. An antibody to CD24 was effective in reducing tumor growth of A549 lung cancer and BxPC3 pancreatic cancer xenografts in mice. Antibody treatment affected the level of Src-phosphorylation in the tumor and altered the expression of STAT3 target genes. Our results provide evidence that CD24 regulates STAT3 and FAK activity and suggest an important role of Src in this process. Finally, the targeting of CD24 by antibodies could represent a novel route for tumor therapy.

The EMT signaling pathways in endometrial carcinoma

Endometrial cancer (EC) is the most common gynecologic malignancy of the female genital tract and the fourth most common neoplasia in women. In EC, myometrial invasion is considered one of the most important prognostic factors. For this process to occur, epithelial tumor cells need to undergo an epithelial to mesenchymal transition (EMT), either transiently or stably, and to differing degrees. This process has been extensively described in other types of cancer but has been poorly studied in EC. In this review, several features of EMT and the main molecular pathways responsible for triggering this process are investigated in relation to EC. The most common hallmarks of EMT have been found in EC, either at the level of E-cadherin loss or at the induction of its repressors, as well as other molecular alterations consistent with the mesenchymal phenotype-like L1CAM and BMI-1 up-regulation. Pathways including progesterone receptor, TGFβ, ETV5 and microRNAs are deeply related to the EMT process in EC.

L1 cell adhesion molecule overexpression in hepatocellular carcinoma associates with advanced tumor progression and poor patient survival

Objective

L1 cell adhesion molecule (L1CAM), as a member of the immunoglobulin superfamily, has recently been observed in a variety of human malignancies. However, no data of L1CAM are available for hepatocellular carcinoma (HCC). The aim of this study was to investigate the expression of L1CAM in HCC and determine its correlation with tumor progression and prognosis.

Methods

One-hundred and thirty HCC patients who had undergone curative liver resection were selected and immunohistochemistry, Western blotting, and quantitative real time polymerase chain reaction (Q-PCR) were performed to analyze L1CAM expression in the respective tumors.

Results

Immunohistochemistry, Western blotting, and Q-PCR consistently confirmed the overexpression of L1CAM in HCC tissues compared with their adjacent nonneoplastic tissues at both protein and gene level (both P <0.01). Additionally, the high expression of L1CAM was significantly associated with advanced tumor stage (P = 0.02) and advanced tumor grade (P = 0.03), respectively. Moreover, HCC patients with high L1CAM expression were significantly associated with lower 5-year overall survival (P <0.01) and lower 5-year disease-free survival (P <0.01), respectively. The Cox proportional hazards model further showed that L1CAM over-expression was an independent poor prognostic factor for both 5-year disease-free survival (P = 0.02) and 5-year overall survival (P = 0.008) in HCC.

Conclusion

Our data suggest for the first time that L1CAM expression in HCC was significantly correlated with the advanced tumor progression and was an independent poor prognostic factor for both overall survival and disease-free survival in patients with HCC.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1970024872761542

EMT-associated up-regulation of L1CAM provides insights into L1CAM-mediated integrin signalling and NF-κB activation

Expression of L1 cell adhesion molecule (L1CAM) is associated with poor prognosis in a variety of human carcinomas including breast, ovarian and pancreatic ductal adenocarcinoma (PDAC). Recently we reported that L1CAM induces sustained nuclear factor kappa B (NF-κB) activation by augmenting the autocrine production of interleukin 1 beta (IL-1β), a process dependent on interaction of L1CAM with integrins. In the present study, we demonstrate that transforming growth factor β1 (TGF-β1) treatment of breast carcinoma (MDA-MB231) and PDAC (BxPc3) cell lines induces an EMT (epithelial to mesenchymal transition)-like phenotype and leads to the expression of L1CAM. In MDA-MB231 cells, up-regulation of L1CAM augmented expression of IL-1β and NF-κB activation, which was reversed by depletion of L1CAM, L1CAM-binding membrane cytoskeleton linker protein ezrin, β1-integrin or focal adhesion kinase (FAK). Over-expression of L1CAM not only induced NF-κB activation but also mediated the phosphorylation of FAK and Src. Phosphorylation was not induced in cells expressing a mutant form of L1CAM (L1-RGE) devoid of the integrin-binding site. FAK- and Src-phosphorylation were inhibited by knock-down of various components of the integrin signalling pathway such as β1- and α5-integrins, integrin-linked kinase (ILK), FAK and the phosphoinositide 3-kinase (PI3K) subunit p110β. In summary, these results reveal that during EMT, L1CAM promotes IL-1β expression through a process dependent on integrin signalling and supports a motile and invasive tumour cell phenotype. We also identify important novel downstream effector molecules of the L1CAM-integrin signalling crosstalk that help to understand the molecular mechanisms underlying L1CAM-promoted tumour progression.

Pancreatic stellate cells promotes the perineural invasion in pancreatic cancer

Perineural invasion is a prominent characteristic of pancreatic cancer. Pancreatic cancer has an extremely high incidence of perineural invasion which has been associated with poor survival. Early studies mostly focus on the interaction between cancer cells and nerves. Recently, the effect of pancreatic stellate cells in progression of pancreatic cancer has been paid more attention. Both in vitro studies and in vivo ones revealed that pancreatic stellate cells can enhance the proliferation, migration and invasion of pancreatic cancer cells. Pancreatic stellate cells can also regulate the expression and effect of molecules involved in perineural invasion. In addition, pancreatic stellate cells seems to associated with the generation of neuronal plasticity in pancreatic cancer. Herein the hypothesis that pancreatic stellate cells play a potential role in promote the perineural invasion in pancreatic cancer through three mechanisms. One is that pancreatic stellate cells enhance the proliferation, migration and invasion directly through releasing a variety of stimuli and providing a suitable microenvironment. Pancreatic stellate cells also regulate the expression and effects of molecules involved in perineural invasion such as nerve growth factor. Another is that pancreatic stellate cells induce neuronal plasticity, which makes nerves more vulnerable to be invaded. We can conclude that pancreatic stellate cells play a central role in regulating the perineural invasion process by producing different effects on cancer cells and nerve. To inhibit the activity of pancreatic stellate cells or block the interaction between pancreatic stellate cells and cancer cells or nerve tissue might reduce the perineural invasion in pancreatic cancer.

Progesterone inhibits epithelial-to-mesenchymal transition in endometrial cancer

BACKGROUND

Every year approximately 74,000 women die of endometrial cancer, mainly due to recurrent or metastatic disease. The presence of tumor infiltrating lymphocytes (TILs) as well as progesterone receptor (PR) positivity has been correlated with improved prognosis. This study describes two mechanisms by which progesterone inhibits metastatic spread of endometrial cancer: by stimulating T-cell infiltration and by inhibiting epithelial-to-mesenchymal cell transition (EMT).

METHODOLOGY AND PRINCIPAL FINDINGS

Paraffin sections from patients with (n = 9) or without (n = 9) progressive endometrial cancer (recurrent or metastatic disease) were assessed for the presence of CD4+ (helper), CD8+ (cytotoxic) and Foxp3+ (regulatory) T-lymphocytes and PR expression. Progressive disease was observed to be associated with significant loss of TILs and loss of PR expression. Frozen tumor samples, used for genome-wide expression analysis, showed significant regulation of pathways involved in immunesurveillance, EMT and metastasis. For a number of genes, such as CXCL14, DKK1, DKK4, PEG10 and WIF1, quantitive RT-PCR was performed to verify up- or downregulation in progressive disease. To corroborate the role of progesterone in regulating invasion, Ishikawa (IK) endometrial cancer cell lines stably transfected with PRA (IKPRA), PRB (IKPRB) and PRA+PRB (IKPRAB) were cultured in presence/absence of progesterone (MPA) and used for genome-wide expression analysis, Boyden- and wound healing migration assays, and IHC for known EMT markers. IKPRB and IKPRAB cell lines showed MPA induced inhibition of migration and loss of the mesenchymal marker vimentin at the invasive front of the wound healing assay. Furthermore, pathway analysis of significantly MPA regulated genes showed significant down regulation of important pathways involved in EMT, immunesuppression and metastasis: such as IL6-, TGF-β and Wnt/β-catenin signaling.

CONCLUSION

Intact progesterone signaling in non-progressive endometrial cancer seems to be an important factor stimulating immunosurveilance and inhibiting transition from an epithelial to a more mesenchymal, more invasive phenotype.

Dual REST-dependence of L1CAM: from gene expression to alternative splicing governed by Nova2 in neural cells

L1 cell adhesion molecule (L1CAM), an adhesion/signaling protein encoded by a gene target of the transcription repressor RE-1-Silencing Transcription factor (REST), is expressed in two alternatively spliced isoforms. The full-length isoform, typical of low-REST neural cells, plays key roles in survival/migration, outgrowth/fasciculation/regeneration of axons, synaptic plasticity; the isoform missing two mini-exons, abundant in a few high-REST non-neural cells, maintains some effect on migration and proliferation. To investigate whether and how L1CAM alternative splicing depends on REST we used neural cell models expressing low or high levels of REST (PC12, SH-SY5Y, differentiated NT2/D1 and primary neurons transduced or not with REST). The short isoform was found to rise when the low-REST levels of neural cells were experimentally increased, while the full-length isoform increased in high-REST cells when the repressor tone was attenuated. These results were due to Nova2, a neural cell-specific splicing factor shown here to be repressed by REST. REST control of L1CAM occurs therefore by two mechanisms, transcription and alternative splicing. The splicing mechanism, affecting not only L1CAM but all Nova2 targets (∼7% of brain-specific splicing, including the mRNAs of other adhesion and synaptic proteins) is expected to be critical during development and important also for the structure and function of mature neural cells.

L1 cell adhesion molecule as a novel independent poor prognostic factor in gallbladder carcinoma

Gallbladder carcinoma is a lethal malignancy and is hard to cure by current treatment. Thus, identification of molecular prognostic markers to predict gallbladder carcinoma as therapeutic targets is urgently needed. Recent studies have demonstrated that L1 cell adhesion molecule is associated with the prognosis of variable malignancy. Here, we investigated L1 cell adhesion molecule expression in gallbladder carcinoma and its prognostic significance. In this study, we examined L1 cell adhesion molecule expression in tumor specimens from 69 patients with gallbladder carcinoma by immunohistochemistry and analyzed the correlation between L1 cell adhesion molecule expression and clinicopathologic factors or survival. L1 cell adhesion molecule was not expressed in the normal epithelium of the gallbladder but in 63.8% of gallbladder carcinomas, remarkably at the invasive front of the tumors. In addition, L1 cell adhesion molecule expression was significantly associated with high histologic grade, advanced pathologic T stage and clinical stage, and positive venous/lymphatic invasion. Multivariate analyses showed that L1 cell adhesion molecule expression (hazard ratio, 3.503; P = .028) and clinical stage (hazard ratio, 3.091; P = .042) were independent risk factor for disease-free survival. L1 cell adhesion molecule expression in gallbladder carcinoma was significantly correlated with tumor progression and unfavorable clinicopathologic features. L1 cell adhesion molecule expression was an independent poor prognostic factor for disease-free survival in patients with gallbladder carcinoma. Taken together, our findings suggest that L1 cell adhesion molecule expression could be used as a novel prognostic factor for patient survival and might be a potential therapeutic target in gallbladder carcinomas.

Linking L1CAM-mediated signaling to NF-κB activation

The cell adhesion molecule L1 (L1CAM) was originally identified as a neural adhesion molecule essential for neurite outgrowth and axon guidance. Many studies have now shown that L1CAM is overexpressed in human carcinomas and associated with poor prognosis. So far, L1CAM-mediated cellular signaling has been largely attributed to an association with growth factor receptors, referred to as L1CAM-'assisted' signaling. New data demonstrate that L1CAM can signal via two additional mechanisms: 'forward' signaling via regulated intramembrane proteolysis and 'reverse' signaling via the activation of the transcription factor nuclear factor (NF)-κB. Taken together, these findings lead to a new understanding of L1CAM downstream signaling that is fundamental for the development of anti-L1CAM antibody-mediated therapeutics in human tumor cells.