Overexpression of CRKL correlates with malignant cell proliferation in breast cancer

Comprehensive DNA methylation profiling by MeDIP-NGS identifies potential genes and pathways for epithelial ovarian cancer

Ovarian cancer, among all gynecologic malignancies, exhibits the highest incidence and mortality rate, primarily because it is often presents with non-specific or no symptoms during its early stages. For the advancement of Ovarian Cancer Diagnosis, it is crucial to identify the potential molecular signatures that could significantly differentiate between healthy and ovarian cancerous tissues and can be used further as a diagnostic biomarker for detecting ovarian cancer. In this study, we investigated the genome-wide methylation patterns in ovarian cancer patients using Methylated DNA Immunoprecipitation (MeDIP-Seq) followed by NGS. Identified differentially methylated regions (DMRs) were further validated by targeted bisulfite sequencing for CpG site-specific methylation profiles. Furthermore, expression validation of six genes by Quantitative Reverse Transcriptase-PCR was also performed. Out of total 120 differentially methylated genes (DMGs), 68 genes were hypermethylated, and 52 were hypomethylated in their promoter region. After analysis, we identified the top 6 hub genes, namely POLR3B, PLXND1, GIGYF2, STK4, BMP2 and CRKL. Interestingly we observed Non-CpG site methylation in the case of POLR3B and CRKL which was statistically significant in discriminating ovarian cancer samples from normal controls. The most significant pathways identified were focal adhesion, the MAPK signaling pathway, and the Ras signaling pathway. Expression analysis of hypermethylated genes was correlated with the downregulation of the genes. POLR3B and GIGYF2 turned out to be the novel genes associated with the carcinogenesis of EOC. Our study demonstrated that methylation profiling through MeDIP-sequencing has effectively identified six potential hub genes and pathways that might exacerbate our understanding of underlying molecular mechanisms of ovarian carcinogenesis.

USP53 Exerts Tumor-Promoting Effects in Triple-Negative Breast Cancer by Deubiquitinating CRKL

Breast cancer (BC) ranks in the top five malignant tumors in terms of morbidity and mortality rates. Among BC subtypes, TNBC has a high recurrence rate and metastasis rate and the worst prognosis. However, the exact mechanism by which TNBC develops is unclear. Here, we show that the deubiquitinase USP53 contributes to tumor growth and metastasis in TNBC. USP53 is overexpressed in TNBC, and this phenotype is linked to a poor prognosis. Functionally, USP53 promotes TNBC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). More importantly, USP53 decreases the chemosensitivity of BC cells by enhancing v-crk sarcoma virus CT10 oncogene homologue (avian)-like (CRKL) expression. Mechanistically, USP53 directly binds CRKL to stabilize and deubiquitinate it, thereby preventing CRKL degradation. Overall, we discovered that USP53 deubiquitinates CRKL, encourages tumor development and metastasis, and reduces chemosensitivity in TNBC. These findings imply that USP53 might represent a new therapeutic target for the treatment of TNBC.

Relationship between tumor microbiota transcriptional activity and gene expression in breast cancer

BACKGROUND

A few studies have reported the distribution of the microbiota in breast cancer tissues, but few reports have compared the microbiota in different subtypes of breast cancer tissue. Moreover, no study has reported on the relationship between the microbiota and gene expression in breast tumor.

METHODS

Sections of formalin-fixed paraffin-embedded (FFPE) tissue were prepared from the breast tumors of 70 patients and were subjected to microarray analysis to identify gene expression profiles. The same total RNA samples were also used to analyze the microbiota activity in tumor tissues by performing 16 S rRNA sequencing and internal transcribed spacer (ITS) sequencing of reverse transcript cDNA with Illumina Miseq. Pearson's correlation coefficient was used for calculating the correlation between microbial relative activity and gene expression.

RESULTS

The microbiota transcriptional activity of 70 FFPE samples mainly consisted of the phyla Bacteroidetes, Firmicutes and Proteobacteria. Prevotella_9, Bacteroides and Alloprevotella were the most active genera in ER+/HER2-, ER+/HER2 + and ER-/HER2 + tumors, while triple-negative samples exhibited a higher activity of Lactobacillus. In ER-negative samples (triple-negative and ER-/HER2+), 479 genes, including the breast carcinogenesis genes phospholipase A2, histone cluster 2, Crk-like, and cyclin D1, were significantly positive associated with the activity of Lactobacillus.

CONCLUSION

This was the first study to clarify an association between the breast tumor microbiota transcriptional activity and the expression of carcinogenesis genes in ER-negative breast cancer. Changes in the microbiota of breast tissue induced by external factors might be one of the key causes of ER negative breast cancer.

Proteomic and functional characterization of intra-tumor heterogeneity in human endometrial cancer

Endometrial cancer is one of the most frequently diagnosed gynecological cancers worldwide, and its prevalence has increased by more than 50% over the last two decades. Despite the understanding of the major signaling pathways driving the growth and metastasis of endometrial cancer, clinical trials targeting these signals have reported poor outcomes. The heterogeneous nature of endometrial cancer is suspected to be one of the key reasons for the failure of targeted therapies. In this study, we perform a sequential window acquisition of all theoretical fragment ion spectra (SWATH)-based comparative proteomic analysis of 63 tumor biopsies collected from 20 patients and define differences in protein signature in multiple regions of the same tumor. We develop organoids from multiple biopsies collected from the same tumor and show that organoids capture heterogeneity in endometrial cancer growth. Overall, using quantitative proteomics and patient-derived organoids, we define the heterogeneous nature of endometrial cancer within a patient’s tumor.

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Proteomic analysis of endometrial cancer intra-tumor heterogeneity

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Identification of potential biomarkers of tumor volume and invasion

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Protein signatures correlate with pre-and postmenopausal cancers

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Patient-derived organoids capture endometrial cancer heterogeneity

Crk and CrkL as Therapeutic Targets for Cancer Treatment

Crk and CrkL are cellular counterparts of the viral oncoprotein v-Crk. Crk and CrkL are overexpressed in many types of human cancer, correlating with poor prognosis. Furthermore, gene knockdown and knockout of Crk and CrkL in tumor cell lines suppress tumor cell functions, including cell proliferation, transformation, migration, invasion, epithelial-mesenchymal transition, resistance to chemotherapy drugs, and in vivo tumor growth and metastasis. Conversely, overexpression of tumor cells with Crk or CrkL enhances tumor cell functions. Therefore, Crk and CrkL have been proposed as therapeutic targets for cancer treatment. However, it is unclear whether Crk and CrkL make distinct or overlapping contributions to tumor cell functions in various cancer types because Crk or CrkL have been examined independently in most studies. Two recent studies using colorectal cancer and glioblastoma cells clearly demonstrated that Crk and CrkL need to be ablated individually and combined to understand distinct and overlapping roles of the two proteins in cancer. A comprehensive understanding of individual and overlapping roles of Crk and CrkL in tumor cell functions is necessary to develop effective therapeutic strategies. This review systematically discusses crucial functions of Crk and CrkL in tumor cell functions and provides new perspectives on targeting Crk and CrkL in cancer therapy.

Quantitative assessment of glioblastoma phenotypes in vitro establishes cell migration as a robust readout of Crk and CrkL activity

The expression levels of CT10 regulator of kinase (Crk) and Crk-like (CrkL) are elevated in many human cancers, including glioblastoma (GBM), and are believed to contribute to poor prognosis. Although Crk and CrkL have been proposed as therapeutic targets in these tumors, the lack of a reliable, quantitative assay to measure Crk and CrkL activity has hindered development of inhibitors. Here, we knocked down Crk, CrkL, or both using siRNAs in a human GBM cell line, U-118MG, to determine the respective, quantitative contributions of Crk and CrkL to cellular phenotypes. The combined use of specific and potent Crk and CrkL siRNAs induced effective knockdown of CrkII, CrkI, and CrkL. Whereas Crk knockdown did not affect cell morphology, proliferation, adhesion, or invasion, CrkL knockdown caused shrinkage of cells and inhibition of cell proliferation, adhesion, and invasion. Crk/CrkL double knockdown resulted in more pronounced morphological alterations and more robust inhibition of proliferation, adhesion, and invasion. Furthermore, Crk/CrkL double knockdown completely blocked cell migration, and this effect was rescued by transient overexpression of CrkL but not of Crk. Quantification of protein levels indicated that CrkL is expressed more abundantly than CrkII and CrkI in U-118MG cells. These results demonstrate both the predominant role of CrkL and the essential overlapping functions of Crk and CrkL in U-118MG cells. Furthermore, our study indicates that migration of U-118MG cells depends entirely on Crk and CrkL. Thus, impedance-based, real-time measurement of tumor cell migration represents a robust assay for monitoring Crk and CrkL activities.

miR-124-3p Suppresses the Invasiveness and Metastasis of Hepatocarcinoma Cells via Targeting CRKL

Abnormal expressions of microRNAs are involved in growth and progression of human cancers including hepatocellular carcinoma (HCC). An adaptor protein CRKL plays a pivotal role in HCC growth, whereas miR-124-3p downregulation is associated with clinical stage and the poor survival of patients. However, the relationship between miR-124-3p and CRKL and the molecular mechanisms through which they regulate HCC metastasis remains unclear. In the current work, we explored miR-124-3p and its correlation with CRKL expression in HCC patient tissues. We found that miR-124-3p deficiency is inversely co-related with CRKL overexpression in tumorous tissues of HCC patients, which was also consistent in HCCLM3 and Huh7 HCC cell lines. Target validation data shows that miR-124-3p directly targets CRKL. The overexpression of miR-124-3p reverses the CRKL expression at both mRNA and protein levels and inhibits the cell development, migration, and invasion. Mechanistic investigations showed that CRKL downregulation suppresses the ERK pathway and EMT process, and concomitant decrease in invasion and metastasis of HCC cells. The expressions of key molecules in the ERK pathway such as RAF, MEK, ERK1/2, and pERK1/2 and key promoters of EMT such as N-cadherin and vimentin were downregulated, whereas E-cadherin, a key suppression indicator of EMT, was upregulated. MiR-124-3p-mediated CRKL suppression led to BAX/BCL-2 increase and C-JUN downregulation, which inhibited the cell proliferation and promoted the apoptosis in HCC cells. Collectively, our data illustrates that miR-124-3p acts as an important tumor-suppressive miRNA to suppress HCC carcinogenesis through targeting CRKL. The miR-124-3p-CRKL axial regulated pathway may offer valuable indications for cancer research, diagnosis, and treatment.

Copy number gains of the putative CRKL oncogene in laryngeal squamous cell carcinoma result in strong nuclear expression of the protein and influence cell proliferation and migration

Laryngeal squamous cell carcinoma is a major medical problem worldwide. Although our understanding of genetic changes and their consequences in laryngeal cancer has opened new therapeutic pathways over the years, the diagnostic as well as treatment options still need to be improved. In our previous study, we identified CRKL (22q11) as a novel putative oncogene overexpressed and amplified in a subset of LSCC tumors and cell lines. Here we analyze to what extent CRKL DNA copy number gains correlate with the higher expression of CRKL protein by performing IHC staining of the respective protein in LSCC cell lines (n = 3) and primary tumors (n = 40). Moreover, the importance of CRKL gene in regard to proliferation and motility of LSCC cells was analyzed with the application of RNA interference (siRNA). Beside the physiological cytoplasmic expression, the analysis of LSCC tumor samples revealed also nuclear expression of CRKL protein in 10/40 (25%) cases, of which three (7.5%), presented moderate or strong nuclear expression. Similarly, we observed a shift towards aberrantly strong nuclear abundance of the CRKL protein in LSCC cell lines with gene copy number amplifications. Moreover, siRNA mediated silencing of CRKL gene in the cell lines showing its overexpression, significantly reduced proliferation (p < 0.01) as well as cell migration (p < 0.05) rates. Altogether, these results show that the aberrantly strong nuclear localization of CRKL is a seldom but recurrent phenomenon in LSCC resulting from the increased DNA copy number and overexpression of the gene. Moreover, functional analyses suggest that proliferation and migration of the tumor cells depend on CRKL expression.

MicroRNA-429 inhibits bone metastasis in breast cancer by regulating CrkL and MMP-9

Bone metastasis is common in late-stage breast cancer patients and leads to skeletal-related events that affect the quality of life and decrease survival. Numerous miRNAs have been confirmed to be involved in metastatic breast cancer, such as the miR200 family. Our previous study identified microRNA-429 (miR-429) as a regulatory molecule in breast cancer bone metastasis. However, the effects of miR-429 and its regulatory axis in the metastatic breast cancer bone microenvironment have not been thoroughly investigated. We observed a positive correlation between miR-429 expression in clinical tissues and the bone metastasis-free interval and a negative correlation between miR-429 expression and the degree of bone metastasis. We cultured bone metastatic MDA-MB-231 cells and used conditioned medium (CM) to detect the effect of miR-429 on osteoblast and osteoclast cells in vitro. We constructed an orthotopic bone destruction model and a left ventricle implantation model to examine the effect of miR-429 on the metastatic bone environment in vivo. The transfection experiments showed that the expression levels of V-crk sarcoma virus CT10 oncogene homolog-like (CrkL) and MMP-9 were negatively regulated by miR-429. The in vitro coculture experiments showed that miR-429 promoted osteoblast differentiation and that CrkL promoted osteoclast differentiation. The two animal models showed that miR-429 diminished local bone destruction and distant bone metastasis but CrkL enhanced these effects. Furthermore, CrkL and MMP-9 expression decreased simultaneously in response to increased miR-429 expression. These findings further reveal the possible mechanism and effect of the miR-429/CrkL/MMP-9 regulatory axis in the bone microenvironment in breast cancer bone metastasis.

Increased Soluble CrkL in Serum of Breast Cancer Patients Is Associated with Advanced Disease

Over-expression of Crk-like protein (CrkL), an intracellular adaptor protein, in breast cancer biopsies has been linked to poor prognosis. CrkL can be secreted from cancer cells binding to β1 integrin on the cell membrane. In this study, we evaluated, for the first time, the levels of soluble CrkL in serum of breast cancer patients. Expression of CrkL and secreted fractions from human breast cancer cell lines and clinical patient samples were assessed by immunohistochemistry and Enzyme Linked Immuno-Sorbent Assay (ELISA). CrkL levels in tissues and sera of patients with different disease stages were compared and statistically analyzed by Chi-square test and Student’s t-test. Culture media from human breast cancer cell lines SUM159, MDA-MB231, and MCF7 showed over a 21-, 15-, and 11-fold higher concentration of soluble CrkL as compared to normal breast epithelium cell line MCF10A. Expression of CrkL was elevated in 85% of breast tumor tissue sections. Serum levels of CrkL were significantly higher in breast cancer patients than in healthy donors. All patients with metastatic disease had significantly elevated concentration of soluble CrkL in the serum with on average three-fold increase from the baseline. The data suggest that soluble fraction of CrkL can be further evaluated as a serum biomarker for advanced disease in breast cancer patients.

CRKL regulates alternative splicing of cancer-related genes in cervical cancer samples and HeLa cell

BACKGROUND

Aberrant spliced isoforms are specifically associated with cancer progression and metastasis. The cytoplasmic adaptor CRKL (v-crk avian sarcoma virus CT10 oncogene homolog-like) is a CRK like proto-oncogene, which encodes a SH2 and SH3 (src homology) domain-containing adaptor protein. CRKL is tightly linked to leukemia via its binding partners BCR-ABL and TEL-ABL, upregulated in multiple types of human cancers, and induce cancer cell proliferation and invasion. However, it remains unclear whether signaling adaptors such as CRKL could regulate alternative splicing.

METHODS

We analyzed the expression level of CRKL in 305 cervical cancer tissue samples available in TCGA database, and then selected two groups of cancer samples with CRKL differentially expressed to analyzed potential CRKL-regulated alternative splicing events (ASEs). CRKL was knocked down by shRNA to further study CRKL-regulated alternative splicing and the activity of SR protein kinases in HeLa cells using RNA-Seq and Western blot techniques. We validated 43 CRKL-regulated ASEs detected by RNA-seq in HeLa cells, using RT-qPCR analysis of HeLa cell samples and using RNA-seq data of the two group of clinical cervical samples.

RESULTS

The expression of CRKL was mostly up-regulated in stage I cervical cancer samples. Knock-down of CRKL led to a reduced cell proliferation. CRKL-regulated alternative splicing of a large number of genes were enriched in cancer-related functional pathways, among which DNA repair and G2/M mitotic cell cycle, GnRH signaling were shared among the top 10 enriched GO terms and KEGG pathways by results from clinical samples and HeLa cell model. We showed that CRKL-regulated ASEs revealed by computational analysis using ABLas software in HeLa cell were highly validated by RT-qPCR, and also validated by cervical cancer clinical samples.

CONCLUSIONS

This is the first report of CRKL-regulation of the alternative splicing of a number of genes critical in tumorigenesis and cancer progression, which is consistent with CRKL reported role as a signaling adaptor and a kinase. Our results underline that the signaling adaptor CRKL might integrate the external and intrinsic cellular signals and coordinate the dynamic activation of cellular signaling pathways including alternative splicing regulation.

MicroRNA-379 Suppresses Cervical Cancer Cell Proliferation and Invasion by Directly Targeting V-crk Avian Sarcoma Virus CT10 Oncogene Homolog-Like (CRKL)

Cervical cancer is the fourth most common malignancy among females worldwide. MicroRNA-379 (miR-379) is aberrantly expressed in multiple human cancer types. However, the expression pattern, roles, and detailed regulatory mechanisms of miR-379 in cervical cancer remain unknown. In this study, we found that miR-379 expression was downregulated in cervical cancer tissues and cell lines. Low miR-379 expression was correlated with International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and distant metastasis. Additionally, miR-379 overexpression suppressed the proliferation and invasion of cervical cancer cells. Furthermore, V-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) was identified as a direct target of miR-379 in cervical cancer. CRKL was upregulated in cancer tissues and negatively correlated with miR-379 expression. Moreover, restored CRKL expression rescued the inhibitory effects of miR-379 overexpression on cell proliferation and invasion. In conclusion, miR-379 may serve as a tumor suppressor in cervical cancer by directly targeting CRKL. Restoring miR-379 expression may be an effective strategy for the treatment of cervical cancer.

HDAC inhibitor suppresses proliferation and invasion of breast cancer cells through regulation of miR-200c targeting CRKL

Although histone deacetylase (HDAC) inhibitors have been shown to effectively induce the inhibition of proliferation and migration in breast cancer, the anticancer mechanism remains poorly understood. Our studies show that miR-200c was significantly downregulated in breast cancer cell lines compared to normal cell lines and inversely correlated with the levels of class IIa HDACs and CRKL. HDAC inhibitors and the ectopic expression of miR-200c as tumor suppressors inhibited the proliferation, invasion, and migration of breast cancer cells by downregulating CRKL. These results indicate that the anticancer mechanism of HDAC inhibitor was realized partially by regulating miR-200c via CRKL targeting. Our findings suggest that the HDAC-miR200c-CRKL signaling axis could be a novel diagnostic marker and potential therapeutic target in breast cancer.

CRKL overexpression promotes cell proliferation and inhibits apoptosis in endometrial carcinoma

The v-Crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) protein is important in cancer progression. However, its expression pattern and biological roles in human endometrial carcinoma remain unexplored. The potential mechanism of CRKL-induced cancer progression is still unclear. The present study aimed to explore the expression pattern and biological roles of CRKL in human endometrial carcinoma. Using immunohistochemistry, it was observed that the CRKL protein was overexpressed in 50.5% (44/87) of endometrial carcinoma tissues. Plasmid transfection of CRKL into Ishikawa cells was performed, and CRKL overexpression promoted cell proliferation, colony formation and cell cycle transition in the transfected cells. In addition, CRKL overexpression inhibited cell apoptosis in Ishikawa cells treated with cisplatin, with decreased caspase-3 and caspase-9 cleavage. Further analysis revealed that CRKL upregulated the expression of cyclin D1, cyclin E, B cell lymphoma (Bcl)-2 and survivin, and downregulated Bcl-2 associated X protein expression. In conclusion, the present study demonstrated that CRKL overexpression in endometrial carcinoma contributes to malignant cell growth and resistance to apoptosis, possibly through Bcl-2.

Crk-like adapter protein is overexpressed in cervical carcinoma, facilitates proliferation, invasion and chemoresistance, and regulates Src and Akt signaling

Overexpression of Crk-like (CrkL) adapter protein has been implicated in a number of types of human cancer. However, its involvement in human cervical carcinoma remains unclear. The present study aimed to explore the clinical significance and biological characteristics of CrkL in human cervical carcinoma. CrkL protein expression was examined in tissue samples from 92 cases of cervical carcinoma using immunohistochemistry, and was found to be overexpressed in 48.9% (45/92 cases). CrkL was transfected into HeLa and CaSki cervical carcinoma cell lines and its effects on biological behavior were examined. CrkL overexpression was revealed to promote cell proliferation, invasion and chemoresistance. In addition, CrkL overexpression increased the level of Src and Akt phosphorylation. Treatment with the Src inhibitor dasatinib eliminated the effect of CrkL on cell invasion. In conclusion, the current results demonstrate that CrkL is an oncoprotein overexpressed in cervical carcinoma which contributes to malignant cell growth and chemoresistance. In addition, the findings indicate that CrkL promotes cervical cancer cell invasion through a Src-dependent pathway.

Reduction of CRKL expression in patients with partial DiGeorge syndrome is associated with impairment of T-cell functions

BACKGROUND

Partial DiGeorge syndrome (pDGS) is caused by deletion of the 22q11.2 region. Within this region lies CrK-like (CRKL), a gene encoding an adapter protein belonging to the Crk family that is involved in the signaling cascade of IL-2, stromal cell-derived factor 1α, and type I interferon. Although recurrent infections can be observed in patients with deletion of chromosome 22 syndrome, the immune pathogenesis of this condition is yet not fully understood.

OBJECTIVE

We aimed to investigate the role of CRKL in T-cell functional responses in patients affected with pDGS.

METHODS

Protein expression levels and phosphorylation of CRKL were evaluated in patients with pDGS. T-cell functional assays in vitro and gene-silencing experiments were also performed.

RESULTS

CRKL protein expression, as well as its phosphorylation, were reduced in all patients with pDGS, especially on IL-2 stimulation. Moreover, T cells presented impaired proliferation and reduced IL-2 production on anti-CD3/CD28 stimulation and decreased c-Fos expression. Finally, CRKL silencing in Jurkat T cells resulted in impaired T-cell proliferation and reduced c-Fos expression.

CONCLUSIONS

The impaired T-cell proliferation and reduction of CRKL, phosphorylated CRKL, and c-Fos levels suggest a possible role of CRKL in functional deficiencies of T cells in patients with pDGS.

CRKL oncogene is downregulated by p53 through miR-200s

Tumor suppressive miRNAs that target oncogenes are frequently downregulated in cancers, and this downregulation leads to oncogene pathway activation. Thus, tumor suppressive miRNAs and their target oncogenes have been proposed as useful targets in cancer treatment. miR-200 family downregulation has been reported in cancer progression and metastasis. The miR-200 family consists of two gene clusters, miR-200b/200a/429 and miR-200c/141, which are located on human chromosomes 1 and 12, respectively. Here, we identified that p53 response elements are located around both clusters of the miR-200 family and confirmed that miR-200s are transcriptional targets of the p53 family. In silico analyses of miRNA targets established the CRKL oncogene as a potential target for miR-200b/200c/429. Moreover, miR-200b/200c/429 inhibited CRKL mRNA and protein expression by directly targeting its 3'-UTR region. Importantly, endogenous CRKL expression was decreased in cancer cells through the introduction of p53 family and endogenous p53 activation. Moreover, the downregulation of CRKL by siRNA inhibited cancer cell growth. The Oncomine database demonstrates that CRKL is overexpressed in a subset of cancer types. Furthermore, CRKL is significantly overexpressed in primary breast cancer tissues harboring mutant TP53. Our results demonstrate that the p53 target miR-200b/200c/429 miRNAs are negative regulators of the CRKL oncogene.

LASP1 is a novel BCR-ABL substrate and a phosphorylation-dependent binding partner of CRKL in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is characterized by a genomic translocation generating a permanently active BCR-ABL oncogene with a complex pattern of atypically tyrosine-phosphorylated proteins that drive the malignant phenotype of CML. Recently, the LIM and SH3 domain protein 1 (LASP1) was identified as a component of a six gene signature that is strongly predictive for disease progression and relapse in CML patients. However, the underlying mechanisms why LASP1 expression correlates with dismal outcome remained unresolved. Here, we identified LASP1 as a novel and overexpressed direct substrate of BCR-ABL in CML. We demonstrate that LASP1 is specifically phosphorylated by BCR-ABL at tyrosine-171 in CML patients, which is abolished by tyrosine kinase inhibitor therapy. Further studies revealed that LASP1 phosphorylation results in an association with CRKL - another specific BCR-ABL substrate and bona fide biomarker for BCR-ABL activity. pLASP1-Y171 binds to non-phosphorylated CRKL at its SH2 domain. Accordingly, the BCR-ABL-mediated pathophysiological hyper-phosphorylation of LASP1 in CML disrupts normal regulation of CRKL and LASP1, which likely has implications on downstream BCR-ABL signaling. Collectively, our results suggest that LASP1 phosphorylation might serve as an additional candidate biomarker for assessment of BCR-ABL activity and provide a first step toward a molecular understanding of LASP1 function in CML.

CrkL meditates CCL20/CCR6-induced EMT in gastric cancer

BACKGROUND

In recent years, Crk-like adapter protein (CrkL) has been identified as a key regulator in the epithelial-to-mesenchymal transition (EMT). However, the molecular mechanisms underlying the CC chemokine receptor 6 (CCR6) and chemokine (C-C motif) ligand 20 (CCL20)-induced EMT in gastric cancer are still unclear.

METHODS

We conducted the immunohistochemistry and immunoblotting to detect the expression of CCR6 and CrkL in 90 cases of gastric cancer tissues and five kinds of cell lines. And then, gastric cancer cells were subjected to small interfering RNA (siRNA) treatment and in vitro assay.

RESULTS

Both CCR6 and CrkL were aberrantly expressed in gastric cancer specimens and closely correlated with differentiation of cell lines. The expression of CCR6 and CrkL was also significantly associated with metastasis, stage, and poor prognosis of gastric cancer. In addition, we validated CCL20 activated the expression of p-CrkL, p-Erk1/2, p-Akt, vimentin, N-cadherin and MMP2 in MGC803 cells in a dose-dependent manner. However, si-CrkL abrogated the CCL20-induced p-Erk1/2, vimentin, N-cadherin and MMP2 expression. Most importantly, the knockdown of CrkL decreased migration and invasion of MGC803 cells.

CONCLUSIONS

CrkL mediates CCL20/CCR6-induced EMT via Akt pathway, instead of Erk1/2 pathway in development of gastric cancer, which indicated CCL20/CCR6-CrkL-Erk1/2-EMT pathway may be targeted to antagonize the progression of gastric cancer.

CRKL knockdown promotes in vitro proliferation, migration and invasion, in vivo tumor malignancy and lymph node metastasis of murine hepatocarcinoma Hca-P cells

Our previous study (Biomed Pharmacother 2015;69:11) demonstrated that the over-expression of CRKL, a chicken tumor virus number 10 regulator of kinase-like protein, suppresses in vitro proliferation, invasion and migration of murine hepatocarcinoma Hca-P cell, a murine HCC cell with lymph node metastatic (LNM) rate of ∼25%. In current work, we investigated the effects of CRKL knockdown on the in vitro cell proliferation, migration and invasion, and on the in vivo tumor malignancy and LNM rate and level for Hca-P cells. Western blotting assay indicated that CRKL was down-regulated by ∼90% in a monoclonal CrkL-shRNA-transfected Hca-P cells. Compared with Hca-P and unrelated-shRNA-transfected Hca-P cell, the in vitro proliferation, migration and invasion potentials were significantly enhanced following CRKL stable deregulation. CRKL knock-down significantly promoted the tumorigenicity malignancy, LNM rates and level of Hca-P-transplanted mice. Consistent with our previous work, it can be concluded CRKL plays an important role in hepatocarcinoma cell proliferation, invasion and migration as well hepatocarcinoma malignancy and metastasis. It functions as a potential tumor suppressor in hepatocarcinoma.

The role of CT10 regulation of kinase-like in cancer

ABSTRACT 

V-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) is a member of CRK family. It acts as an adaptor protein in intracellular signal transduction. CRKL has been reported overexpressed in a variety of cancers affecting the aggressive and malignant behaviors of cancer cells. CRKL seems to show a tumor-promotion role in gastric cancer, glioblastoma multiforme, hepatocellular carcinoma, bladder cancer, lung cancer, colon cancer, ovarian cancer, leukemia, breast cancer, head and neck cancer, rhabdomyosarcoma and neuroblastoma. The association of CRKL with malignant tumors and its potential action mechanisms were summarized. CRKL has the potential to be used as a biomarker for the diagnosis, treatment and prognosis of certain tumors.

CRKL overexpression suppresses in vitro proliferation, invasion and migration of murine hepatocarcinoma Hca-P cells

The signal adaptor CRK family protein play important roles in cancer cell progression, proliferation, migration and invasion. Previously, we showed that CRK was involved in lymphatic metastatic potential of murine hepatocarcinoma cells. In current work, as a member of CRK family, chicken tumour virus number 10 regulator of kinase-like protein (CRKL) was revealed to be associated with malignant behaviors of Hca-P, a murine HCC cell with lymph node metastatic (LNM) rate of ∼25%. CRKL overexpression in Hca-P by a constructed eukaryotic expression vector of pcDNA3.1/V5-HisB-CRKL significantly ameliorated its malignant biological properties. CCK-8 and soft agar colony formation assays indicated CRKL overexpression significantly inhibits the cell proliferation and colony formation abilities of Hca-P. Additionally, transwell assays indicated that the Hca-P cell migration and invasion capacities were apparently reduced following CRKL overexpression. As Hca-P is an ideal hepatocarcinoma cell model with low (initial) LNM potential, CRKL is shown to act as a potential suppressor and to provide new insight for both the malignant behaviors of hepatocarcinoma cells and lymphatic metastasis mechanism of hepatocarcinoma.

The clinical implications of Crk-like adaptor protein expression in papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PMC) is the most common subtype of thyroid carcinomas with satisfactory prognosis. Crk-like (CrkL) adaptor protein was identified in the development of many carcinomas. However, the clinical implications of CrkL protein in PMC were still unknown. Here, we conducted immunohistochemistry to test and analyze CrkL expression in papillary thyroid carcinoma (PTC) (50 cases), PMC (50 cases), and nodular goiter (50 cases), and then western blot further identified the expression of CrkL proteins. In our present study, the positive rate and the mean optical density (MOD) value of CrkL expression in PTC and PMC tissues were statistically significantly different, compared with nodular goiter (p = 0.021, 0.037) and normal thyroid tissues (p = 0.003, 0.009), respectively. In addition, CrkL expression was not associated with age, gender, and tumor number. Conversely, significant differences between CrkL expression and metastasis (p < 0.01) and violation of capsule (p < 0.01) were observed. Notably, western blot indeed identified that the metastasis group of either PTC or PMC tissues had about twofold increased expression of CrkL compared with their non-metastasis groups (p < 0.05). In conclusion, CrkL is highly expressed in papillary thyroid carcinoma and papillary thyroid microcarcinoma and closely correlated to metastasis. Therefore, it is essential to carry out neck lymph node clearance in patients with papillary thyroid microcarcinoma.

The association of Crk-like adapter protein with poor prognosis in glioma patients

Glioma is the most common of brain tumors that greatly affects patient survival. In our precious study, Crk-like adapter protein (CrkL) was identified as a key regulator in glioblastoma development [1]. Here, we aimed to investigate the correlation of CrkL with patient prognosis as well as pathological indicators. Immunohistochemistry was available to evaluate CrkL expression in 49 gliomas of distinct malignancy grade, and positive stained sites were analyzed. CrkL protein was detected in cell lines by Western blot as well. We observed CrkL protein stained in 59.2 % (29 out of 49) of all glioma tissues, including 41.4 % of low-grade (I + II) gliomas, and 85.0 % of high-grade (III + IV) gliomas. Of four grades, grade IV exhibited the highest CrkL level. CrkL protein was also identified in cell lines NHA, U87, U251, T98G, and A172 by Western blot. On the other hand, CrkL expression was significantly associated with the patient's age and WHO grade, and patients with high CrkL expression had a significantly shorter median survival time (17 months) than those (median survival time 52 months) with low CrkL expression (p<0.001). According to Cox regression, CrkL can be suggested as an independent prognostic factor. In conclusion, CrkL is differently expressed in different grades of gliomas, and correlated to WHO grade. CrkL also independently indicates poor prognosis in old glioma patients, which can further be recommended as an effective prognostic biomarker or therapeutic target.

Clinical significance and biological roles of CRKL in human bladder carcinoma

CRKL encodes an adaptor protein that has been recently reported to be overexpressed in various cancers and associate with the malignant behavior of cancer cells. However, the expression pattern of CRKL protein and its clinical significance in human bladder cancer have not been well characterized to date. In the present study, CRKL expression was analyzed in 82 archived bladder cancer specimens using immunohistochemistry, and the correlations between CRKL expression and clinicopathological parameters were evaluated. We found that CRKL was overexpressed in 31 of 82 (37.8%) bladder cancer specimens. A significant association was observed between CRKL overexpression and tumor status (p = 0.019). To further explore the biological functions of CRKL in bladder cancer, we overexpressed CRKL in BIU-87 and 5637 cell lines. Using CCK8 assay and colony formation assay, we showed that CRKL upregulation increased cell proliferation. In addition, transwell assay showed that CRKL could also facilitate invasion. Further study demonstrated that CRKL upregulation increased cyclin D1 expression and ERK phosphorylation. In conclusion, CRKL is overexpressed in bladder cancer and regulates malignant cell growth and invasion, which makes CRKL a candidate therapeutic target for bladder cancer.