CrkL regulates SDF-1-induced breast cancer biology through balancing Erk1/2 and PI3K/Akt pathways

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.

CRKL, AIFM3, AIF, BCL2, and UBASH3A during Human Kidney Development

We aimed to investigate the spatio-temporal expression of possible CAKUT candidate genes CRKL, AIFM3, and UBASH3A, as well as AIF and BCL2 during human kidney development. Human fetal kidney tissue was stained with antibodies and analyzed by fluorescence microscopy and RT-PCR. Quantification of positive cells was assessed by calculation of area percentage and counting cells in nephron structures. Results showed statistically significant differences in the temporal expression patterns of the examined markers, depending on the investigated developmental stage. Limited but strong expression of CRKL was seen in developing kidneys, with increasing expression up to the period where the majority of nephrons are formed. Results also lead us to conclude that AIFM3 and AIF are important for promoting cell survival, but only AIFM3 is considered a CAKUT candidate gene due to the lack of AIF in nephron developmental structures. Our findings imply great importance of AIFM3 in energy production in nephrogenesis and tubular maturation. UBASH3A raw scores showed greater immunoreactivity in developing structures than mature ones which would point to a meaningful role in nephrogenesis. The fact that mRNA and proteins of CRKL, UBASH3A, and AIFM3 were detected in all phases of kidney development implies their role as renal development control genes.

Rap2B knockdown suppresses malignant progression of hepatocellular carcinoma by inactivating the PTEN/PI3K/Akt and ERK1/2 pathways

Rap2B, belonging to the Ras superfamily of small guanosine triphosphate-binding proteins, is upregulated and contributes to the progression of several tumors by acting as an oncogene, including hepatocellular carcinoma (HCC). However, the mechanism underlying the functional roles of Rap2B in HCC remains unclear. In this study, the evaluation of Rap2B expression in HCC cells and tissues was achieved by qRT-PCR and western blot assays. The effects of Rap2B on the malignant biological behaviors in HCC were explored by means of MTT assay, flow cytometry analysis, and Transwell invasion assay, respectively. Protein levels of Ki67, matrix metalloproteinase (MMP)-2, MMP-9, and cleaved caspase-3, together with the alternations of the ERK1/2 and PTEN/PI3K/Akt pathways were qualified by western blot assay. Further verification of the Rap2B function on HCC tumorigenesis was attained by performing in vivo assays. We found that Rap2B levels were upregulated in HCC tissues and cells. Rap2B silencing led to a reduction of cell-proliferative and invasive abilities, and an increase of apoptosis in HCC cells. In addition, xenograft tumor assay demonstrated that Rap2B silencing repressed HCC xenograft tumor growth in vivo. In addition, we found that Rap2B knockdown significantly inhibited the ERK1/2 and PTEN/PI3K/Akt cascades in HCC cells and xenograft tumor tissues. Together, Rap2B knockdown inhibited HCC-malignant progression, which was involved in inhibiting the ERK1/2 and PTEN/PI3K/Akt pathways. Our findings contribute to understanding of the molecular mechanism of Rap2B in HCC progression.

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.

The N-terminal polypeptide derived from vMIP-II exerts its anti-tumor activity in human breast cancer by regulating lncRNA SPRY4-IT1

Accumulating evidence demonstrates that long non-coding RNA (lncRNA) sprouty4-intron transcript 1 (lncRNA SPRY4-IT1) plays a vital role in the development of breast cancer. However, the underlying mechanism has not been eventually illuminated. We aimed to explore the biological activity of lncRNA SPRY4-IT1 in breast cancer cells and whether N-terminal polypeptide derived from viral macrophage inflammatory protein II (NT21MP) could exert its anti-tumor effect by regulating lncRNA SPRY4-IT1 and its target gene SKA2 Real-time RT-PCR, Western blotting, wound healing, and invasion assays were used to achieve this goal. We found that lncRNA SPRY4-IT1 was highly expressed in breast cancer cells. Moreover, NT21MP markedly inhibited biological effects of breast cancer cells by regulating lncRNA SPRY4-IT1, which was partially achieved through SKA2. Our findings suggested that lncRNA SPRY4-IT1 could serve as a novel biomarker by NT21MP for breast cancer.

Knockdown of TMPRSS3 inhibits gastric cancer cell proliferation, invasion and EMT via regulation of the ERK1/2 and PI3K/Akt pathways

The transmembrane protease, serine 3 (TMPRSS3), a member of the type II transmembrane serine protease family, plays an important role in mediating tissue development, homeostasis and various biological processes. Recently, TMPRSS3 has been reported to be involved in cancer progression. However, the role of TMPRSS3 in gastric cancer (GC) remains largely unknown. In this study, we found that TMPRSS3 was highly expressed in GC tissues and cell lines. Knockdown of TMPRSS3 inhibited GC cell proliferation, invasion and epithelial-mesenchymal transition (EMT) in vitro as well as suppressed GC cell growth and dissemination in vivo. These inhibitory effects were mediated by regulation of the ERK1/2 signaling pathway. Moreover, TMPRSS3-mediated ERK1/2 activation was dependent on the PI3K/Akt pathway. In conclusion, TMPRSS3 contributed to GC progression via activation of the PI3K/Akt/ERK signaling pathway and might act as a therapeutic target for GC treatment.

JWA suppresses the invasion of human breast carcinoma cells by downregulating the expression of CXCR4

Breast cancer is the second leading cause of cancer-associated mortality, and metastatic breast cancer is responsible for 90% of patient mortalities. Given that JWA represses the proliferation, invasion and metastasis of a number of other human tumor cells, including melanoma, esophageal, hepatocellular and gastric carcinomas, via mitogen-activated protein kinase or integrin signaling, the present study investigated the expression and function of JWA in human breast cancers. The results showed that the expression level of JWA was significantly reduced in human primary breast cancers when compared with the paired adjacent tissues. Downregulating JWA enhanced, while overexpressing JWA suppressed, the migration and invasion abilities of the two breast cancer cell lines, MDA-MB-468 and MDA-MB-231, without affecting their proliferations in vitro. In addition, JWA negatively regulated the surface expression of CXCR4 in the two cell lines via proteasome degradation, though not via transcriptional inhibition. Functionally, normalizing the disturbed expressions of CXCR4 largely reversed the inhibitory effect of JWA on cell invasion. These data demonstrated that JWA suppressed the migration/invasion of breast carcinoma cells by downregulating the expression of CXCR4, and suggested that JWA may harbor prognostic and therapeutic potential in patients with breast cancer.

ABCG2 confers promotion in gastric cancer through modulating downstream CRKL in vitro combining with biostatistics mining

ABCG2, member of ATP-binding cassette (ABC) transporter family, is known as crucial regulator related to multi-drug resistance in human tumors and has recently been putatively studied as human carcinoma cell biomarker. While, effects of ABCG2 on human gastric cancer (GC) has not been illustrated thoroughly. In this study, by applying biostatistics mining methods, we observed that ABCG2 is frequently aberrantly expressed in GC patients through exploring dataset of GSE19826 in NCBI GEO database. Contemporary, extreme up-regulation of ABCG2 was discovered in both GC specimens and cell lines of our center, from which we observed high level of ABCG2 associated with GC clinicopathologic features and poor outcomes. Depletion of ABCG2 in MKN-45 GC cells, the cell proliferation was significantly impacted along with cell cycle arrest, and cell apoptosis was induced. Interestingly, combined with data mining of NCBI database, CRKL, a pivotal GC promoter, presents a significant positive correlation with ABCG2. And the expression of CRKL in GC cells was obviously affected through ABCG2 depletion. Simultaneously, over-expression of CRKL in MKN-45 cells significantly rescued most of the phenotypes induced by ABCG2 depletion. Thus, we suggest that ABCG2 is a potential biomarker and target upstream CRKL, which could be further studied for GC diagnosis and therapeutic treatment.

16p11.2 transcription factor MAZ is a dosage-sensitive regulator of genitourinary development

Genitourinary (GU) birth defects are among the most common yet least studied congenital malformations. Congenital anomalies of the kidney and urinary tract (CAKUTs) have high morbidity and mortality rates and account for ∼30% of structural birth defects. Copy number variation (CNV) mapping revealed that 16p11.2 is a hotspot for GU development. The only gene covered collectively by all of the mapped GU-patient CNVs was MYC-associated zinc finger transcription factor (MAZ), and MAZ CNV frequency is enriched in nonsyndromic GU-abnormal patients. Knockdown of MAZ in HEK293 cells results in differential expression of several WNT morphogens required for normal GU development, including Wnt11 and Wnt4. MAZ knockdown also prevents efficient transition into S phase, affects transcription of cell-cycle regulators, and abrogates growth of human embryonic kidney cells. Murine Maz is ubiquitously expressed, and a CRISPR-Cas9 mouse model of Maz deletion results in perinatal lethality with survival rates dependent on Maz copy number. Homozygous loss of Maz results in high penetrance of CAKUTs, and Maz is haploinsufficient for normal bladder development. MAZ, once thought to be a simple housekeeping gene, encodes a dosage-sensitive transcription factor that regulates urogenital development and contributes to both nonsyndromic congenital malformations of the GU tract as well as the 16p11.2 phenotype.

Murine model indicates 22q11.2 signaling adaptor CRKL is a dosage-sensitive regulator of genitourinary development

The spectrum of congenital anomalies affecting either the upper tract (kidneys and ureters) or lower tract (reproductive organs) of the genitourinary (GU) system are fundamentally linked by the developmental origin of multiple GU tissues, including the kidneys, gonads, and reproductive ductal systems: the intermediate mesoderm. Although ∼31% of DiGeorge/del22q11.2 syndrome patients exhibit GU defects, little focus has been placed on the molecular etiology of GU defects in this syndrome. Among del22q11.2 patients exhibiting GU anomalies, we have mapped the smallest relevant region to only five genes, including CRKLCRKL encodes a src-homology adaptor protein implicated in mediating tyrosine kinase signaling, and is expressed in the developing GU-tract in mice and humans. Here we show that Crkl mutant embryos exhibit gene dosage-dependent growth restriction, and homozygous mutants exhibit upper GU defects at a microdissection-detectable rate of 23%. RNA-sequencing revealed that 52 genes are differentially regulated in response to uncoupling Crkl from its signaling pathways in the developing kidney, including a fivefold up-regulation of Foxd1, a known regulator of nephron progenitor differentiation. Additionally, Crkl heterozygous adult males exhibit cryptorchidism, lower testis weight, lower sperm count, and subfertility. Together, these data indicate that CRKL is intimately involved in normal development of both the upper and lower GU tracts, and disruption of CRKL contributes to the high incidence of GU defects associated with deletion at 22q11.2.

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.