Protein Tyrosine Kinase 6 Expression Research Articles

FOXP4-mediated induction of PTK7 activates the Wnt/β-catenin pathway and promotes ovarian cancer development

Ovarian cancer (OV) poses a significant challenge in clinical settings due to its difficulty in early diagnosis and treatment resistance. FOXP4, belonging to the FOXP subfamily, plays a pivotal role in various biological processes including cancer, cell cycle regulation, and embryonic development. However, the specific role and importance of FOXP4 in OV have remained unclear. Our research showed that FOXP4 is highly expressed in OV tissues, with its elevated levels correlating with poor prognosis. We further explored FOXP4’s function through RNA sequencing and functional analysis in FOXP4-deficient cells, revealing its critical role in activating the Wnt signaling pathway. This activation exacerbates the malignant phenotype in OV. Mechanistically, FOXP4 directly induces the expression of protein tyrosine kinase 7 (PTK7), a Wnt-binding receptor tyrosine pseudokinase, which causes abnormal activation of the Wnt signaling pathway. Disrupting the FOXP4-Wnt feedback loop by inactivating the Wnt signaling pathway or reducing FOXP4 expression resulted in the reduction of the malignant phenotype of OV cells, while restoring PTK7 expression reversed this effect. In conclusion, our findings underscore the significance of the FOXP4-induced Wnt pathway activation in OV, suggesting the therapeutic potential of targeting this pathway in OV treatment.

Single-cell SERS imaging of dual cell membrane receptors expression influenced by extracellular matrix stiffness

Membrane receptors perform a diverse range of cellular functions, accounting for more than half of all drug targets. The mechanical microenvironment regulates cell behaviors and phenotype. However, conventional analysis methods of membrane receptors often ignore the effects of the extracellular matrix stiffness, failing to reveal the heterogeneity of cell membrane receptors expression. Herein, we developed an in-situ surface-enhanced Raman scattering (SERS) imaging method to visualize single-cell membrane receptors on substrates with different stiffness. Two SERS substrates, Au@4-mercaptobenzonitrile@Ag@Sgc8c and Au@4-pethynylaniline@Ag@SYL3c, were employed to specifically target protein tyrosine kinase-7 (PTK7) and epithelial cell adhesion molecule (EpCAM), respectively. The polyacrylamide (PA) gels with tunable stiffness (2.5–25 kPa) were constructed to mimic extracellular matrix. The simultaneous SERS imaging of dual membrane receptors on single cancer cells on substrates with different stiffness was achieved. Our findings reveal decreased expression of PTK7 and EpCAM on cells cultured on stiffer substrates and higher migration ability of the cells. The results elucidate the heterogeneity of membrane receptors expression of cells cultured on the substrates with different stiffness. This single-cell analysis method offers an in-situ platform for investigating the impacts of extracellular matrix stiffness on the expression of membrane receptors, providing insights into the role of cell membrane receptors in cancer metastasis.

Identification of immune-associated biomarker for predicting lung adenocarcinoma: bioinformatics analysis and experiment verification of PTK6

BackgroundAbnormal expression of protein tyrosine kinase 6 (PTK6) has been proven to be involved in the development of gynecological tumors. However, its immune-related carcinogenic mechanism in other tumors remains unclear.ObjectiveThe aim of this study was to identify PTK6 as a novel prognostic biomarker in pan-cancer, especially in lung adenocarcinoma (LUAD), which is correlated with immune infiltration, and to clarify its clinicopathological and prognostic significance.MethodsThe prognostic value and immune relevance of PTK6 were investigated by using bio-informatics in this study. PTK6 expression was validated in vitro experiments (lung cancer cell lines PC9, NCI-H1975, and HCC827; human normal lung epithelial cells BEAS-2B). Western blot (WB) revealed the PTK6 protein expression in lung cancer cell lines. PTK6 expression was inhibited by Tilfrinib. Colony formation and the Cell Counting Kit-8 (CCK-8) assay were used to detect cell proliferation. The wound healing and trans-well were performed to analyze the cell migration capacity. Then flow cytometry was conducted to evaluate the cell apoptosis. Eventually, the relationship between PTK6 and immune checkpoints was examined. WB was used to estimate the PD-L1 expression at different Tilfrinib doses.ResultsPTK6 was an independent predictive factor for LUAD and was substantially expressed in LUAD. Pathological stage was significantly correlated with increased PTK6 expression. In accordance with survival analysis, poor survival rate in LUAD was associated with a high expression level of PTK6. Functional enrichment of the cell cycle and TGF-β signaling pathway was demonstrated by KEGG and GSEA analysis. Moreover, PTK6 expression considerably associated with immune infiltration in LUAD, as determined by immune analysis. Thus, the result of vitro experiments indicated that cell proliferation and migration were inhibited by the elimination of PTK6. Additionally, PTK6 suppression induced cell apoptosis. Obviously, PD-L1 protein expression level up-regulated while PTK6 was suppressed.ConclusionPTK6 has predictive value for LUAD prognosis, and could up regulated PD-L1.

PTK6: An emerging biomarker for prognosis and immunotherapeutic response in clear cell renal carcinoma (KIRC)

Kidney renal clear cell carcinoma (KIRC), one of the most prevalent form of kidney carcinoma, is highly aggressive cancer known for significant immune infiltration and high mortality rates. The absence of sensitivity to traditional therapy has spurred the search for new treatments. Protein Tyrosine Kinase 6 (PTK6) is implicated in promoting cancer growth, spread, and metastasis. Our review of The Cancer Genome Atlas database revealed PTK6 overexpression in KIRC, though its specific role in this cancer type was unclear. We investigated PTK6's cancer-promoting roles in KIRC using the database and confirmed our findings with patient-derived tissues. Our analysis showed that elevated PTK6 expression is linked to worse outcomes and higher levels of immune infiltration. It also correlates positively with neo-antigens (NEO) and DNA ploidy changes in KIRC. This research delves into PTK6's role in KIRC development, suggesting PTK6 as a possible biomarker for prognosis and treatment in KIRC.

Multiplex Profiling of Biomarker and Drug Uptake in Single Cells Using Microfluidic Flow Cytometry and Mass Spectrometry.

To perform multiplex profiling of single cells and eliminate the risk of potential sample loss caused by centrifugation, we developed a microfluidic flow cytometry and mass spectrometry system (μCytoMS) to evaluate the drug uptake and induced protein expression at the single cell level. It involves a microfluidic chip for the alignment and purification of single cells followed by detection with laser-induced fluorescence (LIF) and inductively coupled plasma mass spectrometry (ICP-MS). Biofunctionalized nanoprobes (BioNPs), conjugating ∼3000 6-FAM-Sgc8 aptamers on a single gold nanoparticle (AuNP) (Kd = 0.23 nM), were engineered to selectively bind with protein tyrosine kinase 7 (PTK7) on target cells. PTK7 expression induced by oxaliplatin (OXA) uptake was assayed with LIF, while ICP-MS measurement of 195Pt revealed OXA uptake of the drug in individual cells, which provided further in-depth information about the drug in relation to PTK7 expression. At an ultralow flow of ∼0.043 dyn/cm2 (20 μL/min), the chip facilitates the extremely fast focusing of BioNPs labeled single cells without the need for centrifugal purification. It ensures multiplex profiling of single cells at a throughput speed of 500 cells/min as compared to 40 cells/min in previous studies. Using a machine learning algorithm to initially profile drug uptake and marker expression in tumor cell lines, μCytoMS was able to perform in situ profiling of the PTK7 response to the OXA at single-cell resolution for tests done on clinical samples from 10 breast cancer patients. It offers great potential for multiplex single-cell phenotypic analysis and clinical diagnosis.

In-situ SERS monitoring of membrane receptor PTK7 for assessing cancer cell migration at single-cell level on a microfluidic chip

Protein tyrosine kinase-7 (PTK7), an important membrane receptor, is crucial in cell migration. Accumulated evidence suggests that aberrant PTK7 expression is associated with the occurrence of cancer. Lots of research has focused on revealing the role of PTK7 in the development of cancers, the conventional methods need transwell and western blot, masking intrinsic differences among cells, and the integrity of the cells cannot be preserved, which is important for revealing the role of PTK7 on cancer development. Herein, we present a method to monitor the expression of PTK7 receptor at single-cell level using a surface-enhanced Raman scattering (SERS) microfluidic chip. Cell migration channel arrays were designed, and controllable chemical stimulation was generated on the microfluidic chip, enabling the cell migration at single-cell level. Raman reporter-embedded gold@silver core–shell nanoparticles (Au@4-Mercaptobenzonitrile@AgNPs) modified with DNA aptamers (Sgc8) exhibit promising binding ability to cell membrane receptor PTK7. The different migration abilities of cancer cells were accurately distinguished in the microfluidic chip. We explored the reduced expression of PTK7 on high migration ability cells at single-cell level. And the discrimination of different colorectal cancer cells was successfully realized using the SERS probes. The developed platform is expected to provide a powerful tool for investigating tumor heterogeneity and promoting clinical precision medicine.

Loss of MTA2-mediated downregulation of PTK7 inhibits hepatocellular carcinoma metastasis progression by modulating the FAK-MMP7 axis.

The expression of metastasis tumor-associated protein 2 (MTA2) and protein tyrosine kinase 7 (PTK7) is associated with hepatocellular carcinoma (HCC) progression. However, the functional effect and mechanism through which MTA2 regulates PTK7-mediated HCC progression remains unclear. Here, we found that MTA2 knockdown significantly down-regulated PTK7 expression in HCC cells (SK-Hep-1 and PLC/PRF/5). Data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases show that the PTK7 expression level was higher in HCC tissues than in normal liver tissues. In HCC patients, the PTK7 expression level clearly correlated with tumor stage and grade, lower overall survival (OS) correlated positively with MTA2 level, and PTK7 expression acted as a downstream factor for MTA2 expression. In addition, matrix metalloproteinase 7 (MMP7) expression was closely regulated by PTK7, and the mRNA and protein expression levels of MTA2 and PTK7 correlated positively with lower OS. MMP7 downregulation by PTK7 knockdown clearly decreased the migration and invasion abilities of HCC cells. In HCC cells, recombinant human MMP7 reversed the PTK7 knockdown-induced suppression of migration and invasion. Furthermore, deactivation of FAK using siFAK or FAK inhibitor (PF-573228, PF) synergistically contributed to PTK7 knockdown-inhibited FAK activity, MMP7 expression, and the migration and invasion abilities of HCC cells. Collectively, our findings show that PTK7 mediates HCC progression by regulating the MTA2-FAK-MMP7 axis and may be a diagnostic value for HCC patients.

Knockdown of PTK7 Reduces the Oncogenic Potential of Breast Cancer Cells by Impeding Receptor Tyrosine Kinase Signaling.

Protein tyrosine kinase 7 (PTK7), a catalytically defective receptor tyrosine kinase (RTK), is often upregulated in various cancers. This study aimed to validate PTK7 as a target for breast cancer (BC) and investigate its oncogenic signaling mechanism. BC tissue analysis showed significantly elevated PTK7 mRNA levels, especially in refractory triple-negative breast cancer (TNBC) tissues, compared with normal controls. Similarly, BC cell lines exhibited increased PTK7 expression. Knockdown of PTK7 inhibited the proliferation of T-47D and MCF-7 hormone-receptor-positive BC cell-lines and of HCC1187, MDA-MB-231, MDA-MB-436, and MDA-MB-453 TNBC cells. PTK7 knockdown also inhibited the adhesion, migration, and invasion of MDA-MB-231, MDA-MB-436, and MDA-MB-453 cells, and reduced the phosphorylation levels of crucial oncogenic regulators including extracellular signal-regulated kinase (ERK), Akt, and focal adhesion kinase (FAK). Furthermore, PTK7 interacts with fibroblast growth factor receptor 1 (FGFR1) and epidermal growth factor receptor (EGFR) expressed in MDA-MB-231 cells. Knockdown of PTK7 decreased the growth-factor-induced phosphorylation of FGFR1 and EGFR in MDA-MB-231 cells, indicating its association with RTK activation. In conclusion, PTK7 plays a significant role in oncogenic signal transduction by enhancing FGFR1 and EGFR activation, influencing BC tumorigenesis and metastasis. Hence, PTK7 represents a potential candidate for targeted BC therapy, including TNBC.

Cell Surface Labeling and Detection of Protein Tyrosine Kinase 7 via Covalent Aptamers.

Covalent aptamers are novel biochemical tools for fast and selective transfer of labels to target proteins. Equipped with cleavable electrophiles, these nucleic acid probes enable the installation of functional handles onto native proteins. The high affinity and specificity with which aptamers bind their selected targets allows for quick, covalent labeling that can compete with nuclease-mediated degradation. Here, we introduce the first application of covalent aptamers to modify a specific cell surface protein through proximity-driven label transfer. We targeted protein tyrosine kinase 7 (PTK7), a prominent cancer marker, and demonstrated aptamer-mediated biotin transfer to specific lysine residues on the extracellular domain of the protein. This allowed for tracking of PTK7 expression, localization, and cellular internalization. These studies validate the programmability of covalent aptamers and highlight their applicability in a cellular context, including protein and small molecule delivery.

MiR-503 pleiotropically regulates epithelial-mesenchymal transition and targets PTK7 to control lung cancer metastasis.

In lung cancer patients, most deaths are caused by the distant dissemination of cancer cells. Epithelial-mesenchymal transition (EMT) and collective cell migration are distinct and important mechanisms involved in cancer invasion and metastasis. Additionally, microRNA dysregulation contributes significantly to cancer progression. In this study, we aimed to explore the function of miR-503 in cancer metastasis. Molecular manipulations (silencing or overexpression) were performed to investigate the biological functions of miR-503 including migration and invasion. Reorganization of cytoskeleton was assessed using immunofluorescence and the relationship between miR-503 and downstream protein tyrosine kinase 7 (PTK7) was assessed using quantitative real-time PCR, immunoblotting, and reporter assays. The tail vein metastatic animal experiments were performed. Herein, we demonstrated that the downregulation of miR-503 confers an invasive phenotype in lung cancer cells and provided in vivo evidence that miR-503 significantly inhibits metastasis. We found that miR-503 inversely regulates EMT, identified PTK7 as a novel miR-503 target, and showed the functional effects of miR-503 on cell migration and invasion were restored upon reconstitution of PTK7 expression. As PTK7 is a Wnt/planar cell polarity protein crucial for collective cell movement, these results implicated miR-503 in both EMT and collective migration. However, the expression of PTK7 did not influence EMT induction, suggesting that miR-503 regulates EMT through mechanisms other than PTK7 inhibition. Furthermore, we discovered that PTK7 mechanistically activates focal adhesion kinase (FAK) and paxillin, thereby controlling the reorganization of the cortical actin cytoskeleton. Collectively, miR-503 is capable of governing EMT and PTK7/FAK signaling independently to control the invasion and dissemination of lung cancer cells, indicating that miR-503 represents a pleiotropic regulator of cancer metastasis and hence a potential therapeutic target for lung cancer.

Abstract 4093: Dual targeted CAR immunotherapy for neuroblastoma using γδ T cells

Abstract Cellular immunotherapy for aggressive pediatric solid tumors like neuroblastoma (NB) has focused on autologous products of αβ T cells, that so far, have been uniformly unsuccessful. γδ T cells offer a potentially superior, off-the-shelf therapy that is directly cytotoxic towards tumors without alloreactivity. Furthermore, γδ T cell infiltration of the hostile, solid tumor microenvironment is a prognostic marker of favorable disease outcome. Our team recently opened a first-in-child evaluation of unengineered allogeneic γδ T cells in combination with dinutuximab, an anti-GD2 antibody, and chemotherapy (NCT05400603). Our focus now is to optimize a second-generation γδ T-cell therapy by engineering the expression of tumor targeting chimeric antigen receptors (CAR). We hypothesize that CAR-targeting will further enhance γδ T-cell homing and antitumor potency. While anti-GD2 antibodies have been clinically successful immunotherapies for NB, GD2-targeted cell therapies need improvement. Our team recently validated a novel immunotherapy target for NB, protein tyrosine kinase 7 (PTK7), an inactive tyrosine kinase expressed highly amongst all NBs with low to no normal pediatric tissue expression. We designed a dual-targeting platform directed against both GD2 and PTK7 using γδ T cells, where CARs are separately encoded and dually expressed. Previously optimized transgenes containing GD2 or PTK7 scFv targeting domains followed by a CD8 hinge region, CD28 co-stim/trans-membrane domain, and CD3ζ signalling domain were inserted under the T7 promoter for mRNA production. Purified mRNA was electroporated into γδ T cells following their thaw from cryopreservation. Electroporation titrations were performed to optimize CAR expression to be detected up to 72 hours post-modification, which is compatible with the approximate in vivo lifespan γδ T cells in mice. Simultaneous expression of both CARs appears highest 24 h after electroporation, with ~70% of the target γδ T cell population modified. Anti-GD2/PTK7 γδ T cells are potent against the NB cell line IMR5 (GD2+PTK7+) in a 4 h cytotoxicity assay at effector:target ratios as low as 0.5:1. Importantly, specificity is also shown against NB cell lines genetically engineered to represent the clinical heterogeneity of GD2 and PTK7 expression that may be observed, where the dual CAR therapy is effective against GD2+PTK7+, GD2+PTK7−, and GD2−PTK7+, but not GD2−PTK7− NBs. In conclusion, we developed a dual CAR-based cellular therapy for NB using γδ T cells as an effector population in place of classical αβ T cells. Early studies demonstrate feasibility for innovative dual CAR expression and show promise for strong anti-NB potency. Future work will optimize CAR signaling domains for maximal efficacy in solid tumors, as well as confirm efficacy and safety in vivo with results rapidly translatable into our established γδ T cell clinical trial pipeline. Citation Format: Hunter C. Jonus, Jasmine Y. Lee, Jordan A. Silva, H. Trent Spencer, Kelly C. Goldsmith. Dual targeted CAR immunotherapy for neuroblastoma using γδ T cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4093.

Protein Tyrosine Kinase 7 (PTK7) Promotes Metastasis in Hepatocellular Carcinoma via SOX9 Regulation and TGF-β Signaling

Metastasis is found in most advanced hepatocellular carcinoma (HCC) patients, and it drives tumor recurrence and systemic failure. There is no effective treatment owing to its complex biological features. Many of the molecular drivers of metastasis are crucial players in normal physiology but behave unconventionally during cancer progression. Targeting these molecular drivers for therapy and differentiating them from a physiological background require a detailed examination of the novel mechanisms involved in their activation during metastasis. Publicly available transcriptomic data such as that of TCGA-LIHC and Gene Expression Omnibus were utilized to identify novel targets upregulated in advanced and metastatic HCC. Validation of candidates was assisted by immunohistochemistry performed on tissue microarrays derived from more than 100 HCC patients. Expression of protein tyrosine kinase 7 (PTK7) was studied under the treatment of transforming growth factor-β1 and knockdown of SRY-Box Transcription Factor 9 (SOX9) to delineate upstream regulation, while CRISPR-mediated knockout and lentiviral overexpression of PTK7 in HCC cells were performed to study their functional and signaling consequences. Manipulated HCC cells were injected into mice models either by orthotopic or tail-vein injection to observe for any in vivo pro-metastatic effects. PTK7 was discovered to be the kinase most significantly upregulated in advanced and metastatic HCC, at both transcriptomic and proteomic level. Bioinformatic analyses and functional assays performed in HCC cell lines revealed transforming growth factor-β signaling and SOX9 to be important activators of PTK7 expression. Functionally, enrichment of PTK7 expression could positively regulate metastatic potential of HCC cells in vitro and in lung metastasis models performed in immunodeficient mice. The up-regulation of PTK7 recruited the epithelial-mesenchymal transition components, zinc finger protein SNAI2 (SLUG) and zinc finger E-box-binding homeobox 1 (ZEB1). Our study proposes PTK7 as a novel molecular driver in metastatic HCC, particularly in a transforming growth factor-β-activated microenvironment. The preferential expression of PTK7 resulted in a previously unobserved regulatory effect on the recruitment of epithelial-mesenchymal transition components, which established PTK7 as a potential determinant of specific epithelial-mesenchymal transition status. Therefore, our data support the continual development of PTK7-targeted agents as antimetastatic therapies.

Interference of PTK6/GAB1 signaling inhibits cell proliferation, invasion, and migration of cervical cancer cells.

Protein tyrosine kinase 6 (PTK6) has shown important cancer-promoting effects in a variety of cancer types. Nonetheless, its vital role in cervical cancer has not been completely elucidated. The present study sought to address whether PTK6 is involved in the malignant progression of cervical cancer via its interaction with GRB2-associated binding 1 (GAB1). Western blotting was used to examine PTK6 and GAB1 expression levels. Cell Counting Kit-8, Transwell, wound healing, and terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assays were performed to estimate the corresponding proliferative, migratory, invasive, and apoptotic abilities of the cells. Co-immunoprecipitation (Co-IP) assays confirmed binding of PTK6 to GAB1. The results revealed that the expression levels of PTK6 and GAB1 were markedly increased in cervical cancer cell lines compared with those noted in normal cervical epithelial cells. The cell proliferative, invasive, and migratory activities of cervical cancer cells were reduced in the absence of PTK6 expression, whereas the induction of apoptosis was aggravated under these conditions. The results of the Co-IP assay indicated that PTK6 expression was positively associated with GAB1. In addition, the suppressive effect of PTK6 silencing on the malignant phenotypes of cervical cancer cells was reversed following overexpression of GAB1. In summary, the present study indicated that knockdown of PTK6 expression protected against the malignant progression of cervical cancer, while overexpression of GAB1 counteracted the inhibitory effects of PTK6 knockdown on cervical cancer cells.

High expression of protein tyrosine kinase 7 in oral squamous cell carcinoma: Clinicopathological correlation and prognosis relevance.

BackgroundThe purpose of this study was to evaluate the association between the immunohistochemistry (IHC) of protein tyrosine kinase 7 (PTK7) expression and clinicopathological factors of oral squamous cell carcinoma (OSCC).MethodsTissue specimens were obtained from 80 patients with primary OSCC. IHC scoring was conducted according to the rate of positive cell and staining intensity. We used the IHC score to classify the degree of PTK7 expression and evaluate clinicopathological factors and prognosis.ResultsThe number of the high expression group (IHC Score 2 or 3) was 45 cases and that of the low expression group (IHC Score 0 or 1) was 35 cases. A significant difference between high expression and low expression groups was found in the N category (p = .008), degree of differentiation (p < .001), and pattern of invasion (p < .001). In accordance with the exacerbation of OSCC with respect to three parameters (N category, degree of differentiation, and pattern of invasion), the ratio of high expression of PTK7 increased. The overall 5‐year survival rate was 59.3% in the high expression group and 87.3% in the low expression group (p < .05). The pathological prognostic signs affecting overall survival were evaluated by univariate analysis and multivariate analysis with Cox proportional hazards model and showed an association with lymph node metastasis and invasion patterns.ConclusionThis study suggests that a high IHC score of PTK7 is a potential biomarker for predicting potential metastasis.

Prognostic value of protein tyrosine kinase 6 overexpression in cancers: a meta-analysis.

Protein tyrosine kinase 6 (PTK6) plays an important role in cell proliferation and differentiation. However, the functions of PTK6 appear highly context-dependent and differ depending on the cell type, as well as its intracellular localization. High PTK6 expression in tumor has been associated with poor pathological features and prognosis in some studies, but other studies have reported opposite results. Therefore, we performed this meta-analysis to derive more precise estimations of the association of PTK6 expression with prognosis and clinicopathological features in cancer patients. We conducted a literature search in PubMed, Ovid MEDLINE, and MEDLINE databases to cover all articles published until June 2021. All 1475 patients from the eight studies were included in the meta-analysis. Because of heterogeneity in PTK6 expression in non-tumor tissues, the included studies were divided into two subgroups according to PTK expression in non-tumor tissues: the low expression subgroup (LESG) or high expression subgroup (HESG). Patients with high PTK expression showed significantly worse overall survival (OS) in LESG (Hazard Ratio (HR) = 2.53 [95% Confidence Interval (CI), 1.68-3.83], p < 0.0001), but significantly better OS in HESG (HR = 0.56 [95% CI, 0.40-0.78], p = 0.0006). PTK6 expression also showed different associations with clinicopathological features, such as advanced T classification, stage, and differentiation according to PTK6 expression in non-tumor tissues. PTK6 expression in tumor was a prognostic factor in patients with various cancers, but the direction of prognosis differs, depending on the degree of PTK6 expression in non-tumor tissues.

Molecularly Engineered Aptamers Targeting Tumor Tissue and Cancer Cells for Efficient in Vivo Recognition and Enrichment

Molecularly Engineered Aptamers Targeting Tumor Tissue and Cancer Cells for Efficient in Vivo Recognition and Enrichment

Protein tyrosine kinase 7-knockdown inhibits oral squamous cell carcinoma cell viability, proliferation, migration and invasion via downregulating dishevelled segment polarity protein 3 expression.

Protein tyrosine kinase 7 (PTK7) expression has been reported to be dysregulated and to regulate various cellular activities in numerous types of cancer. However, to the best of our knowledge, the status and role of PTK7 in oral squamous cell carcinoma (OSCC) remains largely unknown. The present study aimed to investigate the involvement of PTK7 in OSCC progression and to determine the potential underlying mechanisms of action. The expression levels of PTK7 and dishevelled segment polarity protein 3 (DVL3) in OSCC cell lines were analyzed using reverse transcription-quantitative PCR and western blotting. A co-immunoprecipitation assay was used to verify the binding association between PTK7 and DVL3. In addition, OSCC cells were transfected with a short hairpin RNA targeting PTK7 or pcDNA-DVL3 overexpression vectors. The effect of PTK7 on OSCC cell viability, proliferation, migration and invasion, and the underlying mechanisms, were investigated using Cell Counting Kit-8, colony formation, wound healing and Transwell assays, respectively. Western blotting was used to analyze the expression levels of proliferation- and migration-associated proteins. The results revealed that the expression levels of both PTK7 and DVL3 were significantly upregulated in OSCC cell lines. In addition, a binding association was identified between PTK7 and DVL3 in SCC-9 cells. The knockdown of PTK7 expression inhibited OSCC cell viability, proliferation, invasion and migration, while the overexpression of DVL3 reversed the inhibitory effects of PTK7-knockdown on OSCC cells. In conclusion, the results of the present study suggested that PTK7 may be a key regulator of OSCC proliferation, migration and invasion, and PTK7-knockdown may inhibit OSCC cell viability, proliferation, invasion and migration by downregulating DVL3 expression. Therefore, PTK7 and DVL3 may represent potential biomarkers for diagnosis and treatment, as well as promising drug targets for OSCC.

Pharmacological targeting PTK6 inhibits the JAK2/STAT3 sustained stemness and reverses chemoresistance of colorectal cancer

BackgroundChemoresistance is the major cause of chemotherapy failure in patients with colorectal cancer (CRC). Protein tyrosine kinase 6 (PTK6) is aberrantly overexpressed in clinical CRC tissues undergoing chemotherapy. We studied if PTK6 contributed to the chemoresistance of CRC in human and mice.MethodsWe obtained tissue samples from patients with CRC and measured the expression of PTK6 by immunohistochemistry. Gain- and loss-of-function assays were performed to study the biological functions of PTK6. We constructed the FLAG-tagged wild type (WT), kinase-dead, and inhibition-defective recombinant mutants of PTK6 to study the effect phosphorylated activation of PTK6 played on CRC cell stemness and chemoresistance. We used small molecule inhibitor XMU-MP-2 to test the influence of PTK6 on sensitivity of CRC cells to 5-FU/L-OHP in both nude mouse and patient-derived xenograft (PDX) animal models.ResultsPTK6 is overexpressed in CRC tissues and plays a stimulatory role in the proliferation and chemoresistance of CRC cells both in vitro and in vivo. PTK6, especially the phosphorylated PTK6, can promote the stemness of CRC cells through interacting with JAK2 and phosphorylating it to activate the JAK2/STAT3 signaling. Pharmacological inhibition of PTK6 using XMU-MP-2 effectively reduces the stemness property of CRC cells and improves its chemosensitivity to 5-FU/L-OHP in both nude mice subcutaneously implanted tumor model and PDX model constructed with NOD-SCID mice.ConclusionsPTK6 interacts with JAK2 and phosphorylates it to activate JAK2/STAT3 signaling to promote the stemness and chemoresistance of CRC cells. Pharmacological inhibition of PTK6 by small molecule inhibitor dramatically enhances the sensitivity to chemotherapy in nude mice and PDX models.

Protein Tyrosine Kinase 7 Regulates EGFR/Akt Signaling Pathway and Correlates With Malignant Progression in Triple-Negative Breast Cancer.

PurposeTriple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer, is associated with high invasiveness, high metastatic occurrence and poor prognosis. Protein tyrosine kinase 7 (PTK7) plays an important role in multiple cancers. However, the role of PTK7 in TNBC has not been well addressed. This study was performed to evaluate the role of PTK7 in the progression of TNBC.MethodsCorrelation of PTK7 expression with clinicopathological parameters was assessed using tissue microarray immunohistochemistry (IHC) staining in 280 patients with breast cancer. PTK7 expression in TNBC (MDA-MB-468, MDA-MB-436 and MDA-MB-231) and non-TNBC (MCF7 and SK-BR-3) breast cancer cell lines were examined using immunoblotting assay. PTK7 correlated genes in invasive breast carcinoma were analyzed using cBioPortal breast cancer datasets including 1,904 patients. PTK7 overexpressed or knockdown TNBC cell lines (MDA-MB-468 and MDA-MB-436) were used to analyze the potential roles of PTK7 in TNBC metastasis and tumor progression. A TNBC tumor bearing mouse model was established to further analyze the role of PTK7 in TNBC tumorigenicity in vivo.ResultsPTK7 is highly expressed in breast cancer and correlates with worse prognosis and associates with tumor metastasis and progression in TNBC. Co-expression analysis and gain- or loss-of-function of PTK7 in TNBC cell lines revealed that PTK7 participates in EGFR/Akt signaling regulation and associated with extracellular matrix organization and migration genes in breast cancer, including COL1A1, FN1, WNT5B, MMP11, MMP14 and SDC1. Gain- or loss-of-function experiments of PTK7 suggested that PTK7 promotes proliferation and migration in TNBC cell lines. PTK7 knockdown MDA-MB-468 cell bearing mouse model further demonstrated that PTK7-deficiency inhibits TNBC tumor progression in vivo.ConclusionThis study identified PTK7 as a potential marker of worse prognosis in TNBC and revealed PTK7 promotes TNBC metastasis and progression via EGFR/Akt signaling pathway.

LncRNA-MALAT1 regulates proliferation and apoptosis of acute lymphoblastic leukemia cells via miR-205-PTK7 pathway.

Long non-coding RNA (lncRNA) MALAT1 has been confirmed to function as an oncogene in various solid tumors. MALAT1 level has been shown to be upregulated in relapsed acute lymphoblastic leukemia (ALL) patients, but the mechanism is unclear. This study aims to investigate the functional roles and underlying mechanisms of MALAT1 in ALL. MALAT1 and miR-205 expression were assessed by real-time quantitative polymerase chain reaction (RT-qPCR). MTT assay and flow cytometry were performed to evaluate cell proliferation and apoptosis, respectively. Protein level of protein tyrosine kinase-7 (PTK7) was detected by Western blot assay. Dual luciferase reporter assay was conducted to confirm the binding of MALAT1 and miR-205, as well as miR-205 and PTK7. The levels of MALAT1 and PTK7 were upregulated in ALL samples. In contrast, miR-205 level was downregulated in ALL in ALL samples. Moreover, MALAT1 silencing or miR-205 overexpression restrained proliferation and promoted apoptosis of ALL cells. Mechanistically, MALAT1 sponged miR-205 to regulate PTK7 expression. In summary, MALAT1 affected ALL cell proliferation and apoptosis via regulating miR-205-PTK7 axis. Our results suggest that MALAT1-miR-205-PTK7 axis participates in the proliferation and apoptosis of ALL, which may provide a potential treatment target for ALL.