Expression profiling identifies new function of collapsin response mediator protein 4 as a metastasis-suppressor in prostate cancer

CircSCAF8 promotes growth and metastasis of prostate cancer through the circSCAF8-miR-140-3p/miR-335-LIF pathway

Circular RNAs (circRNAs) have been increasingly linked to cancer progression. However, the detailed biological functions of circRNAs in prostate cancer (PCa) remain unclear. Using high-throughput circRNA sequencing, we previously identified 18 urine extracellular vesicle circRNAs that were increased in patients with PCa compared with those with benign prostatic hyperplasia. Spearman correlation analysis of the expression levels of the 18 circRNAs between the tumor tissue and matched urine extracellular vesicles in 30 PCa patients showed that circSCAF8 had the highest R² (R² = 0.635, P < 0.001). The Cox proportional hazards regression model was used to estimate the effect of circSCAF8 on progression-free survival. The in vitro and in vivo functional experiments were implemented to investigate the effects of circSCAF8 on the phenotype of PCa. We found that the knockdown of circSCAF8 in PCa cells suppressed the proliferation, migration, and invasion ability, while overexpression of circSCAF8 had the opposite effects. Similar results were observed in vivo. In a cohort of 85 patients who had undergone radical prostatectomy, circSCAF8 expression in PCa tissues was a powerful predictor of progression-free survival (HR = 2.14, P = 0.022). Mechanistically, circSCAF8 can function by binding to both miR-140-3p and miR-335 to regulate LIF expression and activate the LIF-STAT3 pathway that leads to the growth and metastasis of PCa. Collectively, our findings demonstrate that circSCAF8 contributes to PCa progression through the circSCAF8-miR-140-3p/miR-335-LIF pathway.

CRMP4 CpG Hypermethylation Predicts Upgrading to Gleason Score ≥ 8 in Prostate Cancer

Background

This study determined the predictive value of CRMP4 promoter methylation in prostate tissues collected by core needle biopsies for a postoperative upgrade of Gleason Score (GS) to ≥8 in patients with low-risk PCa.

Method

A retrospective analysis of the clinical data was conducted from 631 patients diagnosed with low-risk PCa by core needle biopsy at multiple centers and then underwent Radical Prostatectomy (RP) from 2014-2019. Specimens were collected by core needle biopsy to detect CRMP4 promoter methylation. The pathologic factors correlated with the postoperative GS upgrade to ≥8 were analyzed by logistic regression. The cut-off value for CRMP4 promoter methylation in the prostate tissues collected by core needle biopsy was estimated from the ROC curve in patients with a postoperative GS upgrade to ≥8.

Result

Multivariate logistic regression showed that prostate volume, number of positive cores, and CRMP4 promoter methylation were predictive factors for a GS upgrade to ≥8 (OR: 0.94, 95% CI: 0.91-0.98, P=0.003; OR: 3.16, 95% CI: 1.81-5.53, P<0.001; and OR: 1.43, 95% CI: 1.32-1.55, P<0.001, respectively). The positive predictive rate was 85.2%, the negative predictive rate was 99.3%, and the overall predictive rate was 97.9%. When the CRMP4 promoter methylation rate was >18.00%, the low-risk PCa patients were more likely to escalate to high-risk patients. The predictive sensitivity and specificity were 86.9% and 98.8%, respectively. The area under the ROC curve (AUC) was 0.929 (95% CI: 0.883-0.976; P<0.001). The biochemical recurrence (BCR)-free survival, progression-free survival (PFS), and cancer-specific survival (CSS) were worse in patients with CRMP4 methylation >18.0% and postoperative GS upgrade to ≥8 than in patients without an upgrade (P ≤ 0.002).

Conclusion

A CRMP4 promoter methylation rate >18.00% in prostate cancer tissues indicated that patients were more likely to escalate from low-to-high risk after undergoing an RP. We recommend determining CRMP4 promoter methylation before RP for low-risk PCa patients.

M6A methylation of DEGS2, a key ceramide-synthesizing enzyme, is involved in colorectal cancer progression through ceramide synthesis

N6-methyladenosine (m6A) is the most prevalent RNA epigenetic regulator in cancer. However, the understanding of m6A modification on lipid metabolism regulation in colorectal cancer (CRC) is very limited. Here, we observed that human CRCs exhibited increased m6A mRNA methylation mediated by dysregulation of m6A erasers and readers. By performing methylated RNA-immunoprecipitation sequencing (MeRIP-seq) and transcriptomic sequencing (RNA-seq), we identified DEGS2 as a downstream target of m6A dysregulation. Overexpression or knockdown of DEGS2 confirmed the role of DEGS2 in proliferation, invasion and metastasis of CRC both in vitro and in vivo. Mechanistic studies identified the specific m6A modification site within DEGS2 mRNA, and mutation of this target site was found to drastically enhance the proliferative and invasive ability of CRC cells in vitro and promote tumorigenicity in vivo. Lipidome analysis showed that lipid metabolism was dysregulated in CRC. Moreover, ceramide synthesis was suppressed due to DEGS2 upregulation mediated by m6A modification in CRC tissues. Our findings highlight that the function of DEGS2 m6A methylation in CRC and extend the understanding of the importance of RNA epigenetics in cancer biology.

Low Incidence of High-Grade Pancreatic Intraepithelial Neoplasia Lesions in a Crmp4 Gene-Deficient Mouse Model of Pancreatic Cancer

Pancreatic intraepithelial neoplasia (PanIN), the most common premalignant lesion of the pancreas, is a histologically well-defined precursor to invasive pancreatic ductal adenocarcinoma (PDAC). However, the molecular mechanisms underlying the progression of PanINs have not been fully elucidated. Previously, we demonstrated that the expression of collapsin response mediator protein 4 (CRMP4) in PDAC was associated with poor prognosis. The expression of CRMP4 was also augmented in a pancreatitis mouse model. However, the role of CRMP4 in the progression of PanIN lesions remains uncertain. In the present study, we examined the relationship between CRMP4 expression and progression of PanIN lesions using genetically engineered mouse models. PanIN lesions were induced by peritoneal injection of the cholecystokinin analog caerulein in LSL-KRAS^G12D; Pdx1-Cre (KC-Crmp4 wild-type, WT) mice and LSL-KRAS^G12D; Pdx1-Cre; Crmp4^−/− (KC-Crmp4 knockout, KO) mice. We analyzed pancreatic tissue sections from these mice and evaluated PanIN grade by hematoxylin and eosin staining. CRMP4 expression was examined and the cellular components assessed by immunohistochemistry using antibodies against CRMP4, CD3, and α-smooth muscle actin (SMA). The incidence of high-grade PanIN in KC-Crmp4 WT mice was higher than that in KC-Crmp4 KO animals. CRMP4 was expressed not only in epithelial cells but also in αSMA-positive cells in stromal areas of PanIN lesions. The CRMP4 expression in stromal areas correlated with PanIN grade in WT mice. These results suggested that the expression of CRMP4 in stromal cells may underlie the incidence or progression of PanIN.

Diabetes, an independent poor prognostic factor of non-B non-C hepatocellular carcinoma, correlates with dihydropyrimidinase-like 3 promoter methylation

A concurrent increase in the prevalence of hepatocellular carcinoma (HCC) with that of type 2 diabetes (T2D) and obesity has been reported in the absence of hepatitis B virus surface antigen-negative/hepatitis C virus antibody-negative HCC (NBNC-HCC). However, the prognostic relevance of this association remains unclear. Promoter methylation (PM) of the dihydropyrimidinase-like 3 gene (DPYSL3) has been implicated in virus-related HCC. However, it remains unclear whether T2D influences PM in NBNC-HCC. We determined the influence of T2D on clinicopathological profile and PM of DPYSL3 and CDK2NA in patients with NBNC-HCC who were divided into two groups: non-diabetes (non-DM; n = 46) and diabetes (DM; n = 47). DM was associated with a higher Union for International Cancer Control grade, marginal vascular invasion and tumour cell proliferation irrespective of the duration of T2D as well as higher rates of PM of DPYSL3 than non-DM; however, PM of CDK2NA was similar between both groups. PM of DPYSL3 reduced its expression which inversely correlated with reduced patient survival. In conclusion, T2D is associated with poor prognosis of NBNC-HCC in which a high frequency of PM of DPYSL3 may play a pivotal role in its pathogenesis.

Dysregulation of CRMP2 Post-Translational Modifications Drive Its Pathological Functions

Collapsin response mediator proteins (CRMPs) are a family of ubiquitously expressed, homologous phosphoproteins best known for coordinating cytoskeletal formation and regulating cellular division, migration, polarity, and synaptic connection. CRMP2, the most studied of the five family members, is best known for its affinity for tubulin heterodimers and function in regulating the microtubule network. These functions are tightly regulated by post-translational modifications including phosphorylation, SUMOylation, oxidation, and O-GlcNAcylation. While CRMP2's physiological functions rely mostly on its non-phosphorylated state, dysregulation of CRMP2 phosphorylation and SUMOylation has been reported to be involved in the pathophysiology of multiple diseases including cancer, chronic pain, spinal cord injury, neurofibromatosis type 1, and others. Here, we provide a consolidated update on what is known about CRMP2 signaling and function, first focusing on axonal growth and neuronal polarity, then illustrating the link between dysregulated CRMP2 post-translational modifications and diseases. We additionally discuss the roles of CRMP2 in non-neuronal cells, both in the CNS and regions of the periphery. Finally, we offer thoughts on the therapeutic implications of modulating CRMP2 function in a variety of diseases.

Combined analysis of CRMP4 methylation levels and CAPRA-S score predicts metastasis and outcomes in prostate cancer patients

The present study analyzed the predictive value of combined analysis of collapsin response mediator protein 4 (CRMP4) methylation levels and the Cancer of the Prostate Risk Assessment (CAPRA-S) Postsurgical score of patients who required adjuvant hormone therapy (AHT) after radical prostatectomy (RP). We retrospectively analyzed 305 patients with prostate cancer (PCa) who received RP and subsequent androgen deprivation therapy (ADT). Two hundred and thirty patients with clinically high-risk PCa underwent immediate ADT, and 75 patients with intermediate risk PCa underwent deferred ADT. CRMP4 methylation levels in biopsies were determined, and CAPRA-S scores were calculated. In the deferred ADT group, the values of the hazard ratios for tumor progression and cancer-specific mortality (CSM) in patients with ≥15% CRMP4 methylation were 6.81 (95% CI: 2.34–19.80) and 12.83 (95% CI: 2.16–26.10), respectively. Receiver-operating characteristic curve analysis indicated that CRMP4 methylation levels ≥15% served as a significant prognostic marker of tumor progression and CSM. In the immediate ADT group, CAPRA-S scores ≥6 and CRMP4 methylation levels ≥15% were independent predictors of these outcomes (uni- and multi-variable Cox regression analyses). The differences in the 5-year progression-free survival between each combination were statistically significant. Combining CAPRA-S score and CRMP4 methylation levels improved the area under the curve compared with the CRMP4 or CAPRA-S model. Therefore, CRMP4 methylation levels ≥15% were significantly associated with a poor prognosis and their combination with CAPRA-S score accurately predicted tumor progression and metastasis for patients requiring AHT after RP.

Therapeutic Potential of Small Activating RNAs (saRNAs) in Human Cancers

Background:

RNA is increasingly recognized as a powerful molecule that can be used to control gene expression. Sophisticated, well-engineered RNA-based regulators are being developed as oligotherapeutics.

Methods:

In particular, small activating RNAs (saRNAs) are promising therapeutic options for targeting human diseases. Numerous saRNAs targeting multiple cancers have been developed in preclinical models. One saRNA targeting C/EBPα is currently undergoing clinical trials in liver cancer.

Results and

Conclusion:

In this review, we describe the current working model of the intracellular mechanism of saRNA, discuss the recent progress of saRNA therapeutics in preclinical and clinical trials, and current advances in targeted delivery using aptamers in detail.

DPYSL3 modulates mitosis, migration, and epithelial-to-mesenchymal transition in claudin-low breast cancer

A Clinical Proteomic Tumor Analysis Consortium (CPTAC) proteogenomic analysis prioritized dihydropyrimidinase-like-3 (DPYSL3) as a multilevel (RNA/protein/phosphoprotein) expression outlier specific to the claudin-low (CLOW) subset of triple-negative breast cancers. A PubMed informatics tool indicated a paucity of data in the context of breast cancer, which further prioritized DPYSL3 for study. DPYSL3 knockdown in DPYSL3-positive ([Formula: see text]) CLOW cell lines demonstrated reduced proliferation, yet enhanced motility and increased expression of epithelial-to-mesenchymal transition (EMT) markers, suggesting that DPYSL3 is a multifunctional signaling modulator. Slower proliferation in DPYSL3-negative ([Formula: see text]) CLOW cells was associated with accumulation of multinucleated cells, indicating a mitotic defect that was associated with a collapse of the vimentin microfilament network and increased vimentin phosphorylation. DPYSL3 also suppressed the expression of EMT regulators SNAIL and TWIST and opposed p21 activated kinase 2 (PAK2)-dependent migration. However, these EMT regulators in turn induce DPYSL3 expression, suggesting that DPYSL3 participates in negative feedback on EMT. In conclusion, DPYSL3 expression identifies CLOW tumors that will be sensitive to approaches that promote vimentin phosphorylation during mitosis and inhibitors of PAK signaling during migration and EMT.

CRMP4a suppresses cell motility by sequestering RhoA activity in prostate cancer cells

Objectives: Distant metastasis is a critical factor for cancer-associated death. Our previous studies identified collapsin response mediator protein 4a (CRMP4a) as a metastasis suppressor in prostate cancers. Enhancing CRMP4 expression by promoter-targeted small activating RNAs reduced cell migration in vitro and abolished distal metastasis in mouse xenograft models. In this study, we investigated the mechanism for CRMP4a-mediated suppression of cell migration. Methods: PC-3 cells were stably infected with lentiviruses expressing CRMP4a cDNA or a shRNA sequence. Cytoskeletal organization was analyzed by measuring cellular focal adhesion area and number, percentage of cell area and lamellipodia numbers after phalloidin staining or anti-vinculin immunocytofluorescent staining. Cell migration was evaluated with Transwell^TM chambers coated with MatriGel. RhoA activation was determined with a Rhotekin RBD agarose bead-based assay kit. Lentiviruses harboring RhoA-Q63L or RhoA-T19N mutant constructs were used to overexpress mutant RhoA proteins. Results: CRMP4a overexpression largely reduced while CRMP4a knockdown remarkably increased cytoskeletal organization in PC-3 cells. CRMP4a immunoprecipitation pulled down RhoA but not cdc42 or Rac1 proteins. Manipulating CRMP4a expression levels reversely altered active RhoA levels. Overexpression of RhoA active (Q63L) but not inactive (T19N) mutants reversed CRMP4a-mediated reduction of cancer cell migration while RhoA inhibitor Rhosin diminished CRMP4a shRNA-induced increase of cancer cell migration. CRMP4a overexpression also largely reduced cell spreading that was abolished by overexpressing RhoA active mutant. Conclusion: Our data demonstrated that CRMP4a interacts with RhoA and sequesters its activity, resulting in suppression of cytoskeletal organization, cell migration and spreading.

Calpain-2 triggers prostate cancer metastasis via enhancing CRMP4 promoter methylation through NF-κB/DNMT1 signaling pathway

BACKGROUND

Metastasis is the major cause of cancer-specific death in patients with prostate cancer (PCa). We previously reported that collapsing response mediator protein-4 (CRMP4) is a PCa metastasis-suppressor gene and the hypermethylation in CRMP4 promoter is responsible for the transcription repression in metastatic PCa. However, the underlying mechanisms remain unknown. In this study, we aimed to investigate the role of calpain-2 in CRMP4 promoter hypermethylation and its functional modulation in PCa metastasis.

METHODS

Calpain-2 expression in PCa tissues (n = 87) and its specific mechanisms of functional modulation in CRMP4 expression via limited enzymatic cleavage was investigated. We then focused on the cooperative crosstalk of calpain-2 and NF-κB RelA/p65 in CRMP4 promoter methylation for the initiation of PCa metastasis. Statistical differences between groups were determined using a two-tailed Student's t-test. P < 0.05 indicated statistically significant.

RESULTS

Calpain-2 was differentially upregulated in metastatic PCa compared with localized PCa. Moreover, calpain-2 cleaved CRMP4 into the N-terminally fragment which promoted migration and invasion in PCa cells via nuclear translocation and activation of E2F1-mediated DNA methyltransferase 1 (DNMT1) expression. NF-κB RelA/p65 recruited DNMT1 to bind to and methylate CRMP4 promoter in which Serine276 phosphorylation of p65 was essential. Furthermore, CRMP4 exhibited anti-metastatic function via inhibiting the expression of VEGFC through Semaphorin3B-Neuropilin2 signaling.

CONCLUSION

Calpain-2 may contribute to the promoter methylation of CRMP4 to repress its transcription, leading to the metastasis of PCa via enhancing VEGFC expression.

A survey of metastasis suppressors in Metazoa

Metastasis suppressors are genes/proteins involved in regulation of one or more steps of the metastatic cascade while having little or no effect on tumor growth. The list of putative metastasis suppressors is constantly increasing although thorough understanding of their biochemical mechanism(s) and evolutionary history is still lacking. Little is known about tumor-related genes in invertebrates, especially non-bilaterians and unicellular relatives of animals. However, in the last few years we have been witnessing a growing interest in this subject since it has been shown that many disease-related genes are already present in simple non-bilateral animals and even in their unicellular relatives. Studying human diseases using simpler organisms that may better represent the ancestral conditions in which the specific disease-related genes appeared could provide better understanding of how those genes function. This review represents a compilation of published literature and our bioinformatics analysis to gain a general insight into the evolutionary history of metastasis-suppressor genes in animals (Metazoa). Our survey suggests that metastasis-suppressor genes emerged in three different periods in the evolution of Metazoa: before the origin of metazoans, with the emergence of first animals and at the origin of vertebrates.

Inhibition of cell-adhesion protein DPYSL3 promotes metastasis of lung cancer

BACKGROUND

Our previous screening study suggested that the cell-adhesions protein Dihydropyrimidinase-like 3 (DPYSL3) was a candidate metastatic lung cancer related molecule. This study aimed to analyze the correlation between DPYSL3 and metastatic lung cancer.

METHODS

Stable DPYSL3 knockdown Lewis lung carcinoma (LLC) cells were constructed with a retroviral system. Cell migration and invasion assays were performed to determine the role of DPYSL3 in LLC cells' migration and invasion changes. A metastatic lung tumor model in which the stable DPYSL3 knockdown LLC cells were injected through tail vein was used to analyze the role of DPYSL3 in tumor metastasis in vivo. The correlation between DPYSL3 expression and the survival time of lung cancer patients were analyzed in KMPLOT database.

RESULTS

Knockdown of DPYSL3 promoted the migratory and invasive of LLC cells compared to the control group. Meanwhile, the motility of LLC cells was also increased with the inhibition of DPYSL3. The TGFβ-induced EMT increased when DPYSL3 was inhibited. The expression of EMT markers, TWIST1 and N-cadherin, significantly increased to almost two times with the knockdown of DPYSL3. Furthermore, inhibition of DPYSL3 promoted the progression of metastatic xenograft in C57BL/6 mice. The expression level of DPYSL3 decreased in lung cancer patients with distant metastasis.

CONCLUSIONS

Knockdown of DPYSL3 promoted the metastatic ability of LLC cells in vitro and in vivo.

Isoform expression patterns of EPHA10 protein mediate breast cancer progression by regulating the E-Cadherin and β-catenin complex

Overexpression of EPHA10 protein was reported in concomitance with clinical severity of breast cancer. In this study, we annotate overexpression of EPHA10 protein with changes of isoform expression as EphA10s (EPHA10 isoform 2) and EphA10 (EPHA10 isoform 3). In the process of malignant transformation, secretory protein EphA10s is in low expression, and pseudo-kinase EphA10 is overexpressed and cytoplasmically enriched. Down-regulated EphA10s blunts stabilization of membrane-associate β-catenin via the interaction with ephrin A5. Cytoplasmic EphA10 maintains phosphorylation of E-cadherin. Restoring isoform expression pattern by up-regulated EphA10s and down-regulated cytoplasmic EphA10 inhibits cell invasion and lymph node metastasis by strengthening the stability of the complex of E-cadherin and β-catenin in membrane. Taken together, we defined the novel interaction via expression patterns of EphA10s and EphA10 that promote malignant transformation of breast cancer, and demonstrated the potential benefit in clinical usage.

Collapsin response mediator protein 4 promotor methylation level as a potential predictor for diagnosing primary malignant lymphoma of the prostate

Background

Primary malignant lymphoma of the prostate (PMLP) is prone to occur in the elderly, and it has no significant correlation with lactate dehydrogenase (LDH) and prostate specific antigen (PSA). Clinical symptoms and imaging data of PMLP remain unspecific, and its prognosis is poor. A previous result showed that collapsin response mediator protein 4 (CRMP4) promotor methylation can be used as a predictor for lymph node metastases in prostate biopsies. However, the relationship between CRMP4 promotor methylation and PMLP has not been studied.

Methods

We investigated the clinicopathological features of PMLP and the significance of CRMP4 methylation in PMLP. The clinical data and diagnosis information of 10 patients with PMLP were retrospectively analyzed. The CRMP4 promotor methylation level in paraffin-embedded tissues of the 10 patients with PMLP were determined and then compared to limited prostate cancer (LPCa) and its negative lymph node tissue [LPCa-LN (−) (10 cases)] and also to metastatic prostate adenocarcinoma (mPCa) and its positive lymph node tissue [mPCa-LN (+) (10 cases)]. Methylation of the CRMP4 promotor in each group was analyzed statistically. A receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of CRMP4 methylation in PMLP.

Results

The average methylation value of CRMP4 in 10 PMLP patients, 20 cases of prostate adenocarcinoma tissue, 10 cases LPCa-LN (−) and 10 cases mPCa-LN (+) were 42.3, 30.6, 6.7 and 20.3%, respectively. A Kruskal–Wallis test showed that the difference of CRMP4 methylation was significant (X² = 38.0, P < 0.001). An ROC curve analysis found that CRMP4 methylation > 40.9% could diagnose PMLP. This method had 90% sensitivity and 95% specificity under conditions of CRMP4 methylation > 40.9%. The area under the curve (AUC) was 0.957.

Conclusions

Methylation of the CRMP4 gene was significantly increased in PMLP, and it is expected to become a new predictor for PMLP.

Emerging cancer-specific therapeutic aptamers

PURPOSE OF REVIEW

We will describe recently discovered smart aptamers with tumor specificity, with an emphasis on targeted delivery of novel therapeutic molecules, cancer-specific biomarkers, and immunotherapy.

RECENT FINDINGS

The development of cancer-specific aptamers has facilitated targeted delivery of potent therapeutic molecules to cancer cells without harming nontumoral cells. This specificity also makes it possible to discover novel cancer biomarkers. Furthermore, alternative immune-checkpoint blockade aptamers have been developed for combinational immunotherapy.

SUMMARY

Aptamers selected against cancer cells show cancer specificity, which has great potential for targeting. First, functionalizing targeted aptamers with therapeutic molecule payloads (e.g., small activating RNAs, antimitotic drugs, therapeutic antibodies, and peptides) facilitates successful delivery into cancer cells. This approach greatly improves the therapeutic index by minimizing side-effects in nontumoral cells. Second, cancer-specific proteins have been identified as cancer biomarkers through in-vitro and in-vivo selection, aptamer pull-down assays, and mass spectrometry. These newly discovered biomarkers improve therapeutic intervention and diagnostic specificity. In addition, the development of alternative immune-checkpoint blockade aptamers is suggested for use in combinational immunotherapeutic with current immune blockade regimens, to reduce the resistance and exhaustion of T cells in clinical trials. VIDEO ABSTRACT: http://links.lww.com/COON/A21.

microRNA-130a is an oncomir suppressing the expression of CRMP4 in gastric cancer

Gastric cancer is one of the most common causes of death worldwide, although its incidence has steadily declined in recent years. There is strong evidence that aberrantly expressed microRNAs (miRNAs) are involved in gastric cancer tumorigenesis. Furthermore, CRMP4 is closely associated with the occurrence and development of gastric cancer, and our predictions suggest that miR-130a, which can promote gastric cancer tumorigenesis, is a potential CRMP4 regulator. In this study, we investigated the expression of CRMP4 and miR-130a in human gastric cancer cell lines by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot (WB) examination and direct interactions between miR-130a and CRMP4 by dual-luciferase reporter assay. We also evaluated the biological roles of miR-130a and CRMP4 in gastric cancer cells by flow cytometry, MTT assay, soft agar colony formation assay, and Transwell tests and confirmed CRMP4 function in vivo, using a tumor xenograft model. Our results demonstrated that CRMP4 expression was significantly decreased at both the gene and protein levels, while miR-130a expression was notably increased, in five human gastric cancer cell lines compared with human gastric epithelial cells. Dual-luciferase reporter assays indicated that CRMP4 was the direct target of miR-130a. Moreover, an inverse regulatory relationship between miR-130a and CRMP4 was verified by qRT-PCR and WB, and overexpression of miR-130a in BGC823 cells enhanced apoptosis and cell proliferation, arrested the cell cycle in G0/G1, and facilitated cell colony formation, invasion, migration, and adhesion, while upregulation of CRMP4 had opposite effects. Finally, the growth and weight of transplanted tumors derived from BGC823 cells in which CRMP4 was knocked down were remarkably reduced. These data indicate that miR-130a is an oncomir targeting CRMP4 and could be developed as a potential prognostic factor and a novel therapeutic target in gastric cancer.

Prospective Study of CRMP4 Promoter Methylation in Prostate Biopsies as a Predictor For Lymph Node Metastases

Background

For patients with prostate cancer (PCa), the presence of pelvic lymph node metastasis (LNM) is a strong predictor of poor outcome. However, the approaches with promising sensitivity and specificity to detect LNM are still lacking. We investigated the value of collapsin response mediator protein 4 (CRMP4) promoter methylation in biopsies as a predictor for LNM.

Methods

CRMP4 promoter methylation at two previously identified CpG sites was determined in 80 case-matched biopsy samples (the training set) using bisulfite pyrosequencing. The predictive cutoff value was independently validated using cohort I of 339 PCa patients (Southern China) and cohort II of 328 case patients (Germany, across China). Mann-Whitney U test, the receiver operating characteristic curve, McNemar's test, and logistic regression were used to assess data. All statistical tests were two-sided.

Results

In the training set, CRMP4 promoter methylation (≥15.0% methylated) was statistically significantly associated with LNM (P < 001). Successful validations were achieved in both cohorts I and II (sensitivity = 92.3%, 95% confidence interval [CI] = 79.3 to 97.9, and sensitivity = 92.2%, 95% CI = 81.1 to 97.8, respectively; specificity = 92.7%, 95% CI = 80.2 to 99.1, and specificity = 91.3%, 95% CI = 87.4 to 94.4, respectively). The sensitivity of CRMP4 promoter methylation is superior to conventional MRI (cohort I: 92.3% vs 26.2%, P < 001; cohort II: 92.2% vs 33.3%, P < 001). CRMP4 promoter methylation is an independent predictor of LNM (cohort I: hazard ratio [HR] = 8.35, 95% CI = 5.64 to 12.35, P < 001; cohort II: HR = 12.46, 95% CI = 5.82 to 26.70, P < 001) in a multivariable analysis model.

Conclusion

CRMP4 promoter methylation in diagnostic biopsies could be a robust biomarker for LNM in PCa.

Targeting CRMP-4 by lentivirus-mediated RNA interference inhibits SW480 cell proliferation and colorectal cancer growth

The aim of the present study was to investigate the expression level of collapsin response mediator protein 4 (CRMP-4) in human colorectal cancer (CRC) tissue and to evauluate its impact on SW480 cell proliferation, in addition to tumor growth in a mouse xenograft model. Clinical CRC tissue samples were collected to detect the CRMP-4 protein expression levels using western blot and immunohistochemistry analyses. A specific small interfering RNA sequence targeting the CRMP-4 gene (DPYSL3) was constructed and transfected into an SW480 cell line using a lentivirus vector to obtain a stable cell line with low expression of CRMP-4. The effectiveness of the interference was evaluated using western blot and reverse transcription-quantitative polymerase chain reaction, and the cell proliferation was determined using MTT and BrdU colorimetric methods. Tumor growth was assessed by subcutaneously inoculating the constructed cells into BALB/c nude mice. The protein expression levels of CRMP-4 were markedly increased in colon tumor tissue of the human samples. The proliferation of SW480 cells and the tumor growth rate in nude mice of the si-CPMR-4 group were evidently depressed compared with the si-scramble group. Thus, the present results suggest that CRMP-4 may be involved in the pathogenesis of CRC.

Collapsin response mediator protein 4 isoforms (CRMP4a and CRMP4b) have opposite effects on cell proliferation, migration, and invasion in gastric cancer

Background

Collapsin response mediator proteins (CRMPs) were originally identified in the nervous system and are involved in neuronal development. Similar to CRMP1, CRMP4 has a shorter transcript encoding a short isoform known as CRMP4a, and a longer transcript encoding a long isoform known as CRMP4b. Previous studies have shown that CRMP4a and CRMP4b exhibit opposing functions in neurite outgrowth. In the present study, we aimed to determine whether CRMP4a and CRMP4b have divergent effects in gastric cancer.

Methods

We first analyzed the mRNA and protein expression levels of CRMP4a and CRMP4b in surgical resected specimens, gastric cancer cell lines and normal gastric epithelial cell line GES-1 by quantitative real-time PCR. Open reading frame and CRMP4b shRNA were generated by lentivirus package and stable cells stably expressing CRMP4a open reading frame and CRMP4b shRNA were constructed. Then the roles of CRMP4a and CRMP4b in cell proliferation, cell cycle progression, apoptosis, migration, invasion, and adhesion were determined by cell proliferation assays, flow cytometry analysis, transwell migration and invasion assays, cell Adhesion Assay, and tumorigenicity assays in nude mice, respectively.

Results

CRMP4a expression was lower and CRMP4b expression was higher in tumor tissue samples as compared to paired non-tumor tissue samples. Additionally, CRMP4a expression was lower and CRMP4b expression was higher in gastric cancer cell lines than in the normal gastric epithelial cell line GES-1. CRMP4a overexpression and CRMP4b silencing suppressed cell proliferation in vitro and in vivo. Additionally, CRMP4a overexpression and CRMP4b silencing induced a significant G1-phase arrest and a decrease of the percentage of cells in S-phase. Furthermore, CRMP4a overexpression and CRMP4b silencing inhibited cell migration, invasion, and adhesion. However, neither CRMP4a overexpression nor CRMP4b silencing affected apoptosis.

Conclusion

These results indicate that CRMP4a and CRMP4b have opposite effects on cell proliferation, migration, and invasion in gastric cancer.

Caerulein-induced pancreatitis augments the expression and phosphorylation of collapsin response mediator protein 4

BACKGROUND

Chronic pancreatitis is a significant risk factor for pancreatic cancer. Previously, we demonstrated that the pancreatic cancer cells show enhanced expression of collapsin response mediator protein 4 (CRMP4) that strongly correlates with severe venous invasion, liver metastasis, and poor prognosis. However, involvement of CRMP4 in acute or chronic pancreatitis remains unknown.

METHODS

Acute and chronic pancreatitis mice models were developed by periodic injection of caerulein. The expression levels of CRMP4 and its phosphorylation were examined.

RESULTS

Elevated CRMP4 levels were observed in the infiltrated lymphocytes as well as in the pancreas parenchyma of both acute and chronic pancreatitis. The expression pattern of phosphorylated CRMP4 was similar to that of CRMP4. Cdk5 partially co-localized with the phosphorylated CRMP4.

CONCLUSIONS

Pancreatitis induces CRMP4 expression in the pancreas parenchyma and in the infiltrated lymphocytes. Overlapping expression of CRMP4 and Cdk5 may suggest that the Cdk5 is at least, in part, responsible for the phosphorylation of CRMP4. The results suggest that CRMP4 is involved in the inflammatory response in pancreatitis. Understanding the mechanisms of CRMP4 would help us to develop novel therapeutic strategies against acute or chronic pancreatitis, and pancreatic cancer.

Collapsin response mediator protein-1 (CRMP1) acts as an invasion and metastasis suppressor of prostate cancer via its suppression of epithelial-mesenchymal transition and remodeling of actin cytoskeleton organization

The cancer cells can acquire migration and invasion capacities during the metastasis process through the developmental regulatory program epithelial–mesenchymal-transition (EMT), and through its reverse process mesenchymal–epithelial transition cancer cells can recolonize at distant metastatic sites. Among the multifaceted effects exerted by this program, reorganization of actin cytoskeleton is the key mechanical drive for the invasive properties gained by cancer cells. Collapsin response mediator protein-1 (CRMP1) is a cytosolic phosphoprotein and originally characterized as the mediator of semaphorin 3A signaling involved in axon differentiation during neural development. Here we report that CRMP1 can act as a suppressor of tumorigenicity and metastasis in prostate cancer cells. We demonstrated that CRMP1 exhibited a decreased expression pattern in high-grade prostate cancer tissues and many prostate cancer cell lines, and its downregulation in cancer cells was attributed to histone deacetylation and direct repression of its gene by the EMT regulator Snail. Functional analyses revealed that CRMP1 suppressed EMT in prostate cancer cells, as its knockdown could trigger EMT and enhance in vitro invasion capacity, whereas its overexpression could inhibit EMT and suppress both in vitro invasion and in vivo metastasis capacities of prostate cancer cells. Moreover, CRMP1 overexpression could significantly confer resistance to EMT induced by Snail or transforming growth factor-β1 in prostatic epithelial cells and prostate cancer cells. Finally, we demonstrated that CRMP1 could associate with actin and WAVE1, an activator of actin nucleation complex Arp2/3, and also its knockdown could stabilize F-actin and trigger the formation of stress fibers in prostate cancer cells. Together, our study shows that CRMP1 acts an EMT and metastasis suppressor in prostate cancer cells via its regulation of actin polymerization and also suggests that targeting the CRMP1-actin signaling in actin organization could be a potential strategy for management of prostate cancer metastasis.

Enhancing DPYSL3 gene expression via a promoter-targeted small activating RNA approach suppresses cancer cell motility and metastasis

To explore a novel strategy in suppressing tumor metastasis, we took the advantage of a recent RNA activation (RNAa) theory and used small double-strand RNA molecules, termed as small activating RNAs (saRNA) that are complimentary to target gene promoter, to enhance transcription of metastasis suppressor gene. The target gene in this study is Dihydro-pyrimidinase-like 3 (DPYSL3, protein name CRMP4), which was identified as a metastatic suppressor in prostate cancers. There are two transcriptional variants of DPYSL3 gene in human genome, of which the variant 2 is the dominant transcript (DPYSL3v2, CRMP4a) but is also significantly down-regulated in primary prostate cancers. A total of 8 saRNAs for DPYSL3v1 and 14 saRNAs for DPYSL3v2 were tested in multiple prostate cancer cell lines. While none of the saRNAs significantly altered DPYSL3v1 expression, 4 saRNAs showed a strong enhancing effect on DPYSL3v2 expression, resulting in reduced cell mobility in vitro. To achieve a prostate cancer-specific delivery for in vivo testing, we conjugated the most potent saV2-9 RNA molecule with the prostate-specific membrane antigen (PSMA)-targeting aptamer A10-3.2. The conjugates successful increased DPYSL3v2 gene expression in PSMA-positive but not PSMA-negative prostate cancer cells. In nude mice bearing orthotopic xenograft of prostate cancer, a 10-day consecutive treatment with the saV2-9 conjugates significantly suppress distal metastasis compared to the control saRNAs. Analysis of xenograft tissues revealed that DPYSL3v2 expression was largely increased in saV2-9 conjugate-treated group compared to the control group. In conclusion, DPYSL3v2 promoter-targeted saRNA molecules might be used as an adjunctive therapy to suppress prostate cancer metastasis.

VEGF promotes gastric cancer development by upregulating CRMP4

This study aimed to investigate the precise role of CRMP4 in gastric tumor growth and patient survival. The mRNA and protein expression levels of CRMP4, VEGF and VEGFR2 were validated by qRT-PCR and immunohistochemistry. We investigated the effects on tumor growth of overexpression and knockdown of CRMP4 both in vitro and in vivo by constructing stable gastric cell lines using lentiviral-mediated transduction and shRNA interference-mediated knockdown of CRMP4 expression. We further validated the role of the ERK/AKT signaling pathways in VEGF and CRMP4 expression using ERK and PI3K inhibitors. Increased expression of VEGF and CRMP4 were observed in gastric cancer tissues compared with tumor-adjacent tissue. We found that higher CRPM4 expression was associated with lymph node metastasis, TNM stage, tumor differentiation and poorer prognosis in gastric cancer patients. In HGC27 and SGC7901 gastric cancer cells, VEGF upregulated CRMP4 in time and dose-dependent manners. Overexpression of CRMP4 increased cell proliferation, migration and invasion, whereas knockdown of CRMP4 expression had opposite effects. VEGF activated CRMP4 expression in gastric cancer cells, and this effect was significantly inhibited by MAPK and PI3K inhibitors (PD98059 and LY294002). In mice, CRMP4 overexpression also resulted in increased tumor growth. These results suggest that increased CRMP4 expression mediated by the activation of VEGF signaling facilitates gastric tumor growth and metastasis, which may have clinical implications associated with a reduced survival rate in gastric cancer patients.

Phosphorylation of a splice variant of collapsin response mediator protein 2 in the nucleus of tumour cells links cyclin dependent kinase-5 to oncogenesis

Background

Cyclin-dependent protein kinase-5 (CDK5) is an unusual member of the CDK family as it is not cell cycle regulated. However many of its substrates have roles in cell growth and oncogenesis, raising the possibility that CDK5 modulation could have therapeutic benefit. In order to establish whether changes in CDK5 activity are associated with oncogenesis one could quantify phosphorylation of CDK5 targets in disease tissue in comparison to appropriate controls. However the identity of physiological and pathophysiological CDK5 substrates remains the subject of debate, making the choice of CDK5 activity biomarkers difficult.

Methods

Here we use in vitro and in cell phosphorylation assays to identify novel features of CDK5 target sequence determinants that confer enhanced CDK5 selectivity, providing means to select substrate biomarkers of CDK5 activity with more confidence. We then characterize tools for the best CDK5 substrate we identified to monitor its phosphorylation in human tissue and use these to interrogate human tumour arrays.

Results

The close proximity of Arg/Lys amino acids and a proline two residues N-terminal to the phosphorylated residue both improve recognition of the substrate by CDK5. In contrast the presence of a proline two residues C-terminal to the target residue dramatically reduces phosphorylation rate. Serine-522 of Collapsin Response Mediator-2 (CRMP2) is a validated CDK5 substrate with many of these structural criteria. We generate and characterise phosphospecific antibodies to Ser522 and show that phosphorylation appears in human tumours (lung, breast, and lymphoma) in stark contrast to surrounding non-neoplastic tissue. In lung cancer the anti-phospho-Ser522 signal is positive in squamous cell carcinoma more frequently than adenocarcinoma. Finally we demonstrate that it is a specific and unusual splice variant of CRMP2 (CRMP2A) that is phosphorylated in tumour cells.

Conclusions

For the first time this data associates altered CDK5 substrate phosphorylation with oncogenesis in some but not all tumour types, implicating altered CDK5 activity in aspects of pathogenesis. These data identify a novel oncogenic mechanism where CDK5 activation induces CRMP2A phosphorylation in the nuclei of tumour cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1691-1) contains supplementary material, which is available to authorized users.

Genetic and epigenetic aspects of initiation and progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary cancer of the liver that is predominant in developing countries and is responsible for nearly 600000 deaths each year worldwide. Similar to many other tumors, the development of HCC must be understood as a multistep process involving the accumulation of genetic and epigenetic alterations in regulatory genes, leading to the activation of oncogenes and the inactivation or loss of tumor suppressor genes. Extensive research over the past decade has identified a number of molecular biomarkers, including aberrant expression of HCC-related genes and microRNAs. The challenge facing HCC research and clinical care at this time is to address the heterogeneity and complexity of these genetic and epigenetic alterations and to use this information to direct rational diagnosis and treatment strategies. The multikinase inhibitor sorafenib was the first molecularly targeted drug for HCC to show some extent of survival benefits in patients with advanced tumors. Although the results obtained using sorafenib support the importance of molecular therapies in the treatment of HCC, there is still room for improvement. In addition, no molecular markers for drug sensitivity, recurrence and prognosis are currently clinically available. In this review, we provide an overview of recently published articles addressing HCC-related genes and microRNAs to update what is currently known regarding genetic and epigenetic aspects of the pathogenesis of HCC and propose novel promising candidates for use as diagnostic and therapeutic targets in HCC.

Recent advances in the molecular diagnostics of gastric cancer

Gastric cancer (GC) is the third most common cause of cancer-related death in the world, representing a major global health issue. Although the incidence of GC is declining, the outcomes for GC patients remain dismal because of the lack of effective biomarkers to detect early GC and predict both recurrence and chemosensitivity. Current tumor markers for GC, including serum carcinoembryonic antigen and carbohydrate antigen 19-9, are not ideal due to their relatively low sensitivity and specificity. Recent improvements in molecular techniques are better able to identify aberrant expression of GC-related molecules, including oncogenes, tumor suppressor genes, microRNAs and long non-coding RNAs, and DNA methylation, as novel molecular markers, although the molecular pathogenesis of GC is complicated by tumor heterogeneity. Detection of genetic and epigenetic alterations from gastric tissue or blood samples has diagnostic value in the management of GC. There are high expectations for molecular markers that can be used as new screening tools for early detection of GC as well as for patient stratification towards personalized treatment of GC through prediction of prognosis and drug-sensitivity. In this review, the studies of potential molecular biomarkers for GC that have been reported in the publicly available literature between 2012 and 2015 are reviewed and summarized, and certain highlighted papers are examined.

Dihydropyrimidinase-like 3 is a putative hepatocellular carcinoma tumor suppressor

BACKGROUND

Patients with hepatocellular carcinoma (HCC) may relapse after curative resection. Sensitive biomarkers for HCC are required to enhance disease management. Dihydropyrimidinase-like 3 (DPYSL3) suppresses cell proliferation and tumorigenicity of certain malignancies; however, its role in HCC is unknown.

METHODS

The expression levels of DPYSL3 and genes encoding potential interacting proteins vascular endothelial growth factor (VEGF), focal adhesion kinase (FAK), ezrin, and cellular src were determined using RT-PCR. Further, we determined the methylation status of the DPYSL3 promoter in HCC cells lines and the effect of inhibiting DPYSL3 expression on their phenotype. DPYSL3 expression was determined in 151 pairs of resected liver tissues.

RESULTS

DPYSL3 mRNA levels were down-regulated in most HCC cell lines with DPYSL3 promoter hypermethylation, and expression was restored after demethylation. DPYSL3 expression levels inversely correlated with those of VEGF and FAK. Knockdown of DPYSL3 significantly increased migration and the invasive properties of HCC cells. The mean level of DPYSL3 mRNA was significantly lower in HCC tissues compared with corresponding noncancerous tissues. The expression patterns of DPYSL3 mRNA and protein were consistent. DPYSL3 mRNA expression in HCC tissues inversely correlated with preoperative serum tumor markers and was significantly lower in patients with extrahepatic recurrences. Disease-specific and recurrence-free survival was significantly shorter in patients with down-regulated DPYSL3 expression.

CONCLUSIONS

Our results indicate that DPYSL3 is a putative HCC tumor suppressor, and promoter hypermethylation potently regulates DPYSL3 transcription. Down-regulation of DPYSL3 expression in HCC tissues may serve as a predictive biomarker for HCC after curative resection.

Manipulation of prostate cancer metastasis by locus-specific modification of the CRMP4 promoter region using chimeric TALE DNA methyltransferase and demethylase

Prostate cancer is the most commonly diagnosed non-cutaneous cancer and one of the leading causes of cancer death for North American men. Whereas localized prostate cancer can be cured, there is currently no cure for metastatic prostate cancer. Here we report a novel approach that utilizes designed chimeric transcription activator-like effectors (dTALEs) to control prostate cancer metastasis. Transfection of dTALEs of DNA methyltransferase or demethylase induced artificial, yet active locus-specific CpG and subsequent histone modifications. These manipulations markedly altered expression of endogenous CRMP4, a metastasis suppressor gene. Remarkably, locus-specific CpG demethylation of the CRMP4 promoter in metastatic PC3 cells abolished metastasis, whereas locus-specific CpG methylation of the promoter in non-metastatic 22Rv1 cells induced metastasis. CRMP4-mediated metastasis suppression was found to require activation of Akt/Rac1 signaling and down-regulation of MMP-9 expression. This proof-of-concept study with dTALEs for locus-specific epigenomic manipulation validates the selected CpG methylation of CRMP4 gene as an independent biomarker for diagnosis and prognosis of prostate cancer metastasis and opens up a novel avenue for mechanistic research on cancer biology.

Prospective validation of DACH2 as a novel biomarker for prediction of metastasis and prognosis in muscle-invasive urothelial carcinoma of the bladder

Metastasis is the main cause of death from muscle-invasive urothelial carcinoma of the bladder (UCB), and the metastatic potential of tumors is often unpredictable. The role of Dachshund homolog 2 gene (DACH2) in tumorigenesis remains unexplored. We aimed to investigate whether DACH2 can be used as a biomarker to predict metastasis and prognosis of muscle-invasive UCB in a sequential training and validation fashion. For the training set (n = 40), compared with UCB patients without lymph node (LN) metastasis, both DACH2 protein and mRNA expression were greatly increased in case-matched patients with LN metastasis. For the independent validation set (n = 243), patients with primary UCB that did not express DACH2 had a longer metastasis-free survival (MFS) and overall survival (OS) than did those with tumors expressing DACH2 (5-year MFS: 88% [95% CI 80-96] versus 19% [95% CI 7-31], p < 0.001; 5-year OS: 93% [95% CI 87-99] versus 37% [95% CI 23-51], p < 0.001). Multivariable analysis of DACH2 status showed hazard ratios of 7.34 (95% CI 3.15-11.87, p < 0.001) for MFS and 3.96 (95% CI 2.04-7.16, p < 0.001) for OS which were much higher than hazard ratios associated with other independent risk factors. Collectively, DACH2 is an independent prognostic marker that can be used at initial diagnosis of UCB to identify patients who have a high potential to develop metastasis.

Identification and validation of potential new biomarkers for prostate cancer diagnosis and prognosis using 2D-DIGE and MS

This study was designed to identify and validate potential new biomarkers for prostate cancer and to distinguish patients with and without biochemical relapse. Prostate tissue samples analyzed by 2D-DIGE (two-dimensional difference in gel electrophoresis) and mass spectrometry (MS) revealed downregulation of secernin-1 (P < 0.044) in prostate cancer, while vinculin showed significant upregulation (P < 0.001). Secernin-1 overexpression in prostate tissue was validated using Western blot and immunohistochemistry while vinculin expression was validated using immunohistochemistry. These findings indicate that secernin-1 and vinculin are potential new tissue biomarkers for prostate cancer diagnosis and prognosis, respectively. For validation, protein levels in urine were also examined by Western blot analysis. Urinary vinculin levels in prostate cancer patients were significantly higher than in urine from nontumor patients (P = 0.006). Using multiple reaction monitoring-MS (MRM-MS) analysis, prostatic acid phosphatase (PAP) showed significant higher levels in the urine of prostate cancer patients compared to controls (P = 0.012), while galectin-3 showed significant lower levels in the urine of prostate cancer patients with biochemical relapse, compared to those without relapse (P = 0.017). Three proteins were successfully differentiated between patients with and without prostate cancer and patients with and without relapse by using MRM. Thus, this technique shows promise for implementation as a noninvasive clinical diagnostic technique.

Upregulation of CRMP4, a new prostate cancer metastasis suppressor gene, inhibits tumor growth in a nude mouse intratibial injection model

Prostate cancer, the most commonly diagnosed male cancer in North America, has a high incidence of bone metastasis. Our previous study showed collapsin response mediator protein 4 (CRMP4) gene inhibited prostate cancer migration and invasion. In this study, we investigated whether overexpression of CRMP4 gene in prostate cancer cells inhibit tumor bone metastasis. The stable prostate cancer cells overexpressing the CRMP4 gene were constructed using lentivirus infection. Prostate cancer bone metastasis nude mouse model was built though orthotopic prostate implantation, intracardiac injection and intratibial injection with CRMP4 overexpress and control cancer cells. Small animal PET/CT scanning results showed no difference of bone metastatic capacity in orthotopic and intracardiac injection models between CRMP4 overexpression and control group, while CRMP4 overexpression inhibited tumor growth in the intratibial injection model. Moreover, our in vitro study showed CRMP4 overexpression downregulates the Neuropilin1 (NRP1) expression and upregulate the Noggin expression. Immunohistochemical staining of the hind limbs of intratibial injection model was confirmed with cytological experiments. Taken together, our research indicated CRMP4 inhibits prostate cancer cells growth in the nude mouse bone microenvironment and this effect may relate with regulation of NRP1 and Noggin expression.

Dihydropyrimidinase-like 3 facilitates malignant behavior of gastric cancer

BACKGROUND

Gastric cancer (GC) remains to have a poor prognosis via diverse process of cancer progression. Dihydropyrimidinase-like 3 (DPYSL3) is a cell adhesion molecule that has been reported to be involved in the metastatic process of tumor cells. The aim of this study was to identify a novel clinically-relevant biomarker of GC.

METHODS

Expression analysis of DPYSL3 mRNA and protein levels was conducted using GC cell lines and 238 pairs of surgically resected gastric tissues. Correlations between expression status of DPYSL3 and clinicopathological parameters were investigated.

RESULTS

DPYSL3 mRNA expression levels positively correlated with those of potentially interacting genes (VEGF, FAK and EZR) in GC cell lines. GC tissues from tumors with distant metastases (stage IV cancer) showed elevated expression levels of DPYSL3 mRNA. The DPYSL3 staining intensity in immunochemical staining was consistent with the mRNA expression patterns in GC tissues. High DPYSL3 mRNA expression in GCs was significantly associated with more malignant phenotypes and was an independent prognostic factor. Moreover, patients with high DPYSL3 mRNA expression had a significantly shorter recurrence free survival after curative resection. In subgroup analysis based on tumor histology, similar tendency was observed between patients with differentiated and undifferentiated GCs.

CONCLUSIONS

Expression status of DPYSL3 in GC tissues may represent a promising biomarker for the malignant behavior of GC.

Dihydropyrimidinase-like 3 facilitates malignant behavior of gastric cancer

Background

Gastric cancer (GC) remains to have a poor prognosis via diverse process of cancer progression. Dihydropyrimidinase-like 3 (DPYSL3) is a cell adhesion molecule that has been reported to be involved in the metastatic process of tumor cells. The aim of this study was to identify a novel clinically-relevant biomarker of GC.

Methods

Expression analysis of DPYSL3 mRNA and protein levels was conducted using GC cell lines and 238 pairs of surgically resected gastric tissues. Correlations between expression status of DPYSL3 and clinicopathological parameters were investigated.

Results

DPYSL3 mRNA expression levels positively correlated with those of potentially interacting genes (VEGF, FAK and EZR) in GC cell lines. GC tissues from tumors with distant metastases (stage IV cancer) showed elevated expression levels of DPYSL3 mRNA. The DPYSL3 staining intensity in immunochemical staining was consistent with the mRNA expression patterns in GC tissues. High DPYSL3 mRNA expression in GCs was significantly associated with more malignant phenotypes and was an independent prognostic factor. Moreover, patients with high DPYSL3 mRNA expression had a significantly shorter recurrence free survival after curative resection. In subgroup analysis based on tumor histology, similar tendency was observed between patients with differentiated and undifferentiated GCs.

Conclusions

Expression status of DPYSL3 in GC tissues may represent a promising biomarker for the malignant behavior of GC.

Microenvironmental Influences on Metastasis Suppressor Expression and Function during a Metastatic Cell's Journey

Metastasis is the process of primary tumor cells breaking away and colonizing distant secondary sites. In order for a tumor cell growing in one microenvironment to travel to, and flourish in, a secondary environment, it must survive a series of events termed the metastatic cascade. Before departing the primary tumor, cells acquire genetic and epigenetic changes that endow them with properties not usually associated with related normal differentiated cells. Those cells also induce a subset of bone marrow-derived stem cells to mobilize and establish pre-metastatic niches [1]. Many tumor cells undergo epithelial-to-mesenchymal transition (EMT), where they transiently acquire morphologic changes, reduced requirements for cell-cell contact and become more invasive [2]. Invasive tumor cells eventually enter the circulatory (hematogenous) or lymphatic systems or travel across body cavities. In transit, tumor cells must resist anoikis, survive sheer forces and evade detection by the immune system. For blood-borne metastases, surviving cells then arrest or adhere to endothelial linings before either proliferating or extravasating. Eventually, tumor cells complete the process by proliferating to form a macroscopic mass [3].Up to 90 % of all cancer related morbidity and mortality can be attributed to metastasis. Surgery manages to ablate most primary tumors, especially when combined with chemotherapy and radiation. But if cells have disseminated, survival rates drop precipitously. While multiple parameters of the primary tumor are predictive of local or distant relapse, biopsies remain an imperfect science. The introduction of molecular and other biomarkers [4, 5] continue to improve the accuracy of prognosis. However, the invasive procedure introduces new complications for the patient. Likewise, the heterogeneity of any tumor population [3, 6, 7] means that sampling error (i.e., since it is impractical to examine the entire tumor) necessitates further improvements.In the case of breast cancer, for example, women diagnosed with stage I diseases (i.e., no evidence of invasion through a basement membrane) still have a ~30 % likelihood of developing distant metastases [8]. Many physicians and patients opt for additional chemotherapy in order to "mop up" cells that have disseminated and have the potential to grow into macroscopic metastases. This means that ~ 70 % of patients receive unnecessary therapy, which has undesirable side effects. Therefore, improving prognostic capability is highly desirable.Recent advances allow profiling of primary tumor DNA sequences and gene expression patterns to define a so-called metastatic signature [9-11], which can be predictive of patient outcome. However, the genetic changes that a tumor cell must undergo to survive the initial events of the metastatic cascade and colonize a second location belie a plasticity that may not be adequately captured in a sampling of heterogeneous tumors. In order to tailor or personalize patient treatments, a more accurate assessment of the genetic profile in the metastases is needed. Biopsy of each individual metastasis is not practical, safe, nor particularly cost-effective. In recent years, there has been a resurrection of the notion to do a 'liquid biopsy,' which essentially involves sampling of circulating tumor cells (CTC) and/or cell free nucleic acids (cfDNA, including microRNA (miRNA)) present in blood and lymph [12-16].The rationale for liquid biopsy is that tumors shed cells and/or genetic fragments into the circulation, theoretically making the blood representative of not only the primary tumor but also distant metastases. Logically, one would predict that the proportion of CTC and/or cfDNA would be proportionate to the likelihood of developing metastases [14]. While a linear relationship does not exist, the information within CTC or cfDNA is beginning to show great promise for enabling a global snapshot of the disease. However, the CTC and cfDNA are present at extremely low levels. Nonetheless, newer technologies capture enough material to enrich and sequence the patient's DNA or quantification of some biomarkers.Among the biomarkers showing great promise are metastasis suppressors which, by definition, block a tumor cell's ability to complete the metastatic process without prohibiting primary tumor growth [17]. Since the discovery of the first metastasis suppressor, Nm23, more than 30 have been functionally characterized. They function at various stages of the metastatic cascade, but their mechanisms of action, for the most part, remain ill-defined. Deciphering the molecular interactions of functional metastasis suppressors may provide insights for targeted therapies when these regulators cease to function and result in metastatic disease.In this brief review, we summarize what is known about the various metastasis suppressors and their functions at individual steps of the metastatic cascade (Table 1). Some of the subdivisions are rather arbitrary in nature, since many metastasis suppressors affect more than one step in the metastatic cascade. Nonetheless what emerges is a realization that metastasis suppressors are intimately associated with the microenvironments in which cancer cells find themselves [18].

New concepts concerning prostate cancer screening

Prostate Cancer (CaP) is rapidly becoming a worldwide health issue. While CaP mortality has decreased in recent years, coincident with the widespread use of Prostate-Specific Antigen (PSA) screening, it remains the most common solid tumor in men and is the second leading cause of cancer death in the United States. The frequency of CaP is growing not only in western cultures, but also its incidence is dramatically increasing in eastern nations. Recently, examination of data from long-term trials and follow up has cast a shadow on the effectiveness of employing PSA as a primary screening tool for CaP. In this review, we not only summarize opinions from this examination and synthesize recommendations from several groups that suggest strategies for utilizing PSA as a tool, but also call for research into biomarkers for CaP diagnosis and disease progression. We also describe our recent work that identified a smooth muscle contractile protein in prostate epithelia, namely smooth muscle gamma actin, and indicate the potential for this molecule as a new unique footprint and as a CaP marker.

Crystal structure of human CRMP-4: correction of intensities for lattice-translocation disorder

Collapsin response mediator proteins (CRMPs) are cytosolic phosphoproteins that are mainly involved in neuronal cell development. In humans, the CRMP family comprises five members. Here, crystal structures of human CRMP-4 in a truncated and a full-length version are presented. The latter was determined from two types of crystals, which were either twinned or partially disordered. The crystal disorder was coupled with translational NCS in ordered domains and manifested itself with a rather sophisticated modulation of intensities. The data were demodulated using either the two-lattice treatment of lattice-translocation effects or a novel method in which demodulation was achieved by independent scaling of several groups of intensities. This iterative protocol does not rely on any particular parameterization of the modulation coefficients, but uses the current refined structure as a reference. The best results in terms of R factors and map correlation coefficients were obtained using this new method. The determined structures of CRMP-4 are similar to those of other CRMPs. Structural comparison allowed the confirmation of known residues, as well as the identification of new residues, that are important for the homo- and hetero-oligomerization of these proteins, which are critical to nerve-cell development. The structures provide further insight into the effects of medically relevant mutations of the DPYSL-3 gene encoding CRMP-4 and the putative enzymatic activities of CRMPs.

Collapsin response mediator proteins: Potential diagnostic and prognostic biomarkers in cancers (Review)

The collapsin response mediator proteins (CRMPs) were originally identified as mediators of semaphorin 3A signaling and neuronal differentiation. The CRMP family consists of five homologous cytosolic proteins, CRMP1-5. Altered expression levels of CRMPs have been observed in several malignant tumors, including lung, breast, colorectal, prostate, pancreatic and neuroendocrine lung cancer. The aim of the current study was to review the recent progress achieved in understanding the association between the different levels of CRMP expression in tumors and their involvement in pathological functions, such as tumor metastasis, disease progression, subtype differentiation and clinical outcome, to address the potential value of CRMPs as biomarkers for the diagnosis and prognosis of cancer patients.

Metastasis suppressors in breast cancers: mechanistic insights and clinical potential

For the most part, normal epithelial cells do not disseminate to other parts of the body and proliferate, as do metastatic cells. Presumably, a class of molecules-termed metastasis suppressors-are involved in this homeostatic control. Metastasis suppressors are, by definition, cellular factors that, when re-expressed in metastatic cells, functionally inhibit metastasis without significantly inhibiting tumor growth. In this brief review, we catalog known metastasis suppressors, what is known about their mechanism(s) of action, and experimental and clinical associations to date.

Dihydropyrimidinase-like protein 3 expression is negatively regulated by MYCN and associated with clinical outcome in neuroblastoma

Dihydropyrimidinase-like proteins (DPYSLs) are a family of proteins developmentally regulated during maturation of the nervous system. Recently, members of the DPYSL family have been reported to be involved in cancer with low expression of DPYSL1 correlating with poor clinical outcomes in non-small cell lung cancer and functioning as a metastasis suppressor. Neuroblastoma (NB) is a tumor derived from precursor cells of the sympathetic nervous system and is the most common solid tumor in childhood. So far the biological functions of DPYSLs in NB remain elusive. Studying the potential roles of DPYSLs in NB may give us new insights into NB tumorigenesis. In the present study, using antibodies specific to different members of the DPYSL family, DPYSL1, DPYSL2 and DPYSL3, we investigated regulation of their expression and their subcellular distribution during retinoic acid (RA)-induced differentiation in NB cells. The correlation between DPYSLs and MYCN, a biomarker for poor prognosis of NB, was evaluated. We found that DPYSL3 levels increased during RA-induced cell differentiation. Downregulation of MYCN by small interfering RNA (siRNA) increased DPYSL3 levels, while upregulation of MYCN in non-MYCN NB cells decreased DPYSL3 levels. DPYSL1 and DPYSL2 expression didn't change during RA treatment or under different expression levels of MYCN. Moreover, a high level of DPYSL3 mRNA, but not that of DPYSL1 or DPYSL2 mRNA, was detected in tumors from advanced-stage NB that have a better survival. These data indicated that DPYSL3, not DPYSL1 or DPYSL2, is negatively regulated by MYCN and may be used as a potential biomarker for NB.

Collapsin response mediator protein 2 is involved in regulating breast cancer progression

BACKGROUND

Altered expression of collapsin response mediator proteins (CRMPs) has been reported in several malignant tumors, including downregulation of CRMP1 in lung cancer and upregulation of CRMP2 in colorectal cancer. This study aimed to investigate the relationship between CRMP expression and clinicopathological characteristics in patients with breast cancer.

METHODS

Twenty-two breast cancer and four normal breast tissues were used to assess CRMP mRNA expression. The average expression level of each CRMP (CRMP1-5) mRNA was analyzed in a subset of breast cancer specimens and compared with that in normal breast tissue by real-time quantitative reverse-transcription polymerase chain reaction. Furthermore, 173 breast cancer specimens and matching normal breast controls were used for immunohistochemistry based on the tissue microarray technique. Levels of CRMP2 and phosphorylated CRMP2 protein were assessed, and possible correlations between the clinicopathological characteristics were evaluated.

RESULTS

The expression of CRMP2 mRNA was significantly decreased in breast cancer tissues, while that of the other CRMPs was similar between normal and breast cancer tissues. Immunohistochemistry revealed that CRMP2 protein expression was also decreased in breast cancer tissues (P < 0.001). Phosphorylated CRMP2 was observed in the nuclei of breast cancer cells but not in normal mammary cells (P < 0.001). Furthermore, nuclear phosphorylated CRMP2 expression was increased in proportion to the histological grade and triple-negative subtype.

CONCLUSIONS

Reduced CRMP2 expression and elevated expression of nuclear phosphorylated CRMP2 may be associated with breast cancer progression.

The role of proteomics in prostate cancer research: biomarker discovery and validation

PURPOSE

Prostate Cancer (PCa) represents the second most frequent type of tumor in men worldwide. Incidence increases with patient age and represents the most important risk factor. PCa is mostly characterized by indolence, however in a small percentage of cases (3%) the disease progresses to a metastatic state. To date, the most important issue concerning PCa research is the difficulty in distinguishing indolent from aggressive disease. This problem frequently results in low-grade PCa patient overtreatment and, in parallel; an effective treatment for distant and aggressive disease is not yet available.

RESULT

Proteomics represents a promising approach for the discovery of new biomarkers able to improve the management of PCa patients. Markers more specific and sensitive than PSA are needed for PCa diagnosis, prognosis and response to treatment. Moreover, proteomics could represent an important tool to identify new molecular targets for PCa tailored therapy. Several possible PCa biomarkers sources, each with advantages and limitations, are under investigation, including tissues, urine, serum, plasma and prostatic fluids. Innovative high-throughput proteomic platforms are now identifying and quantifying new specific and sensitive biomarkers for PCa detection, stratification and treatment. Nevertheless, many putative biomarkers are still far from being applied in clinical practice.

CONCLUSIONS

This review aims to discuss the recent advances in PCa proteomics, emphasizing biomarker discovery and their application to clinical utility for diagnosis and patient stratification.

Collapsin response mediator protein 4 expression is associated with liver metastasis and poor survival in pancreatic cancer

BACKGROUND

Pancreatic cancer is an aggressive malignancy with one of the worst mortality rates of all cancers. Recently, collapsin response mediator proteins (CRMPs) were reported to be associated with proliferation, apoptosis, differentiation, and invasion in several cancers. However, CRMP expression and their role in pancreatic cancer have not been investigated. This study aimed to clarify the clinical significance of CRMPs in pancreatic cancer.

METHODS

Expression of crmp genes in 11 pairs of pancreatic cancer and corresponding noncancerous pancreas tissues were examined by real-time RT-PCR. Knockdown of CRMP4 expression using siRNA was examined in pancreatic cancer cell lines to determine whether CRMP4 regulates cell proliferation and invasion in vitro. Furthermore, CRMP4 protein levels in primary tumors of pancreatic cancer (n = 53) were examined by immunohistochemistry and compared with the clinicopathological features of the tumors.

RESULTS

Of all the CRMPs, only CRMP4 was differentially expressed in pancreatic cancer tissues (p = 0.008). CRMP4 knockdown using siRNA reduced cellular invasion, but did not affect proliferation. The expression of CRMP4 was detected immunohistochemically in 34 (64.2 %) of the 53 pancreatic cancer samples, and CRMP4 expression was correlated with severe venous invasion (p = 0.044), stage (p = 0.019), and liver metastasis (p = 0.021). Multivariate analyses suggested that venous invasion and CRMP4 overexpression were prognostic factors for survival.

CONCLUSIONS

Our results suggested that CRMP4 is significantly associated with poor prognosis by promoting liver metastasis and can serve as a novel therapeutic target for pancreatic cancer.

Peroxiredoxins 3 and 4 are overexpressed in prostate cancer tissue and affect the proliferation of prostate cancer cells in vitro

The present study aimed to investigate the proteome profiling of surgically treated prostate cancers. Hereto, 2D-DIGE and mass spectrometry were performed for protein identification, and data validation for peroxiredoxin 3 and 4 (PRDX3 and PRDX4) was accomplished by reverse phase protein arrays (RPPA). The Formal Concept Analysis (FCA) method was applied to assess whether the TMPRSS2-ERG gene fusion could influence the degree of overexpression of PRDX3 and PRDX4 in prostate cancer. Lastly, we performed an in vitro functional characterization of both PRDX3 and PRDX4 using the classical human prostate cancer cell lines DU145 and LNCaP. Reverse phase protein arrays verified that the overexpression of both PRDX3 and PRDX4 in tumor samples is negatively correlated with the presence of the TMPRSS2-ERG gene fusion. Functional characterization of PRDX3 and PRDX4 activity in PCa cell lines suggests a role of these members of the peroxiredoxin family in the pathophysiology of this tumor entity.

A collapsin response mediator protein 2 isoform controls myosin II-mediated cell migration and matrix assembly by trapping ROCK II

Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two binding domains but also trapped and inhibited the kinase. CRMP-2L protein levels profoundly affected haptotactic migration and the actin-myosin cytoskeleton of carcinoma cells as well as nontransformed epithelial cell migration in a ROCK activity-dependent manner. Moreover, the ectopic expression of CRMP-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions through the inhibition of ROCK II in nonneuronal cells.

Tissue proteomics of the human mammary gland: towards an abridged definition of the molecular phenotypes underlying epithelial normalcy

Our limited understanding of the biological impact of the whole spectrum of early breast lesions together with a lack of accurate molecular-based risk criteria for the diagnosis and assignment of prognostic significance to biopsy findings presents an important problem in the clinical management of patients harboring precancerous breast lesions. As a result, there is a need to identify biomarkers that can better determine the outcome of early breast lesions by identifying subpopulations of cells in breast premalignant disease that are at high-risk of progression to invasive disease. A first step towards achieving this goal will be to define the molecular phenotypes of the various cell types and precursors - generated by the stem cell hierarchy - that are present in normal and benign conditions of the breast. To date there have been very few systematic proteomic studies aimed at characterizing the phenotypes of the different cell subpopulations present in normal human mammary tissue, partly due to the formidable heterogeneity of mammary tissue, but also due to limitations of the current proteomic technologies. Work in our laboratories has attempted to address in a systematic fashion some of these limitations and here we present our efforts to search for biomarkers using normal fresh tissue from non-neoplastic breast samples. From the data generated by the 2D gel-based proteomic profiling we were able to compile a protein database of normal human breast epithelial tissue that was used to support the biomarker discovery program. We review and present new data on the putative cell-progenitor marker cytokeratin 15 (CK15), and describe a novel marker, dihydropyriminidase-related protein 3 (DRP3) that in combination with CK15 and other well known proteins were used to define molecular phenotypes of normal human breast epithelial cells and their progenitors in resting acini, lactating alveoli, and large collecting ducts of the nipple. Preliminary results are also presented concerning DRP3 positive usual ductal hyperplasias (UDHs) and on single cell layer columnar cells (CCCs). At least two bona fide biomarkers of undifferentiated ERα/PgR negative luminal cells emerged from these studies, CK15 and c-KIT, which in combination with transformation markers may lead to the establishment of a protein signature able to identify breast precancerous at risk of progressing to invasive disease.