Additional local therapy before disease progression for EGFR-mutated advanced lung cancer: a systematic review and meta-analysis.

Background: International guidelines recommend the use of local therapy (LT) to limited progression in patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC). However, the use of LT before disease progression has not been extensively analyzed. This meta-analysis evaluates the efficacy and safety of administering additional LT in conjunction with first-line EGFR-tyrosine kinase inhibitors (TKIs) before disease progression in patients with EGFR-mutated advanced NSCLC. Methods: We systematically searched PubMed, Embase, and the Cochrane Library for studies published up until May 31, 2023. The LT group consisted of patients who received first-line EGFR-TKIs in conjunction with additional LT, while the TKI group comprised participants treated with first-line EGFR-TKIs alone. Studies comparing the survival outcomes of the LT and TKI groups were included in this analysis. The primary outcomes were progression-free survival (PFS) and overall survival (OS). This review was registered on PROSPERO (registration number CRD42023439913). Results: Among the 11 investigated studies covering 1,313 patients, the LT modalities included radiotherapy, surgery, and ablation therapy, which accounted for 91%, 27%, and 27% of the studies, respectively. The pooled hazard ratios of median PFS and OS were 0.34 [95% confidence interval (CI): 0.22-0.53; P<0.001] and 0.42 (95% CI: 0.36-0.48; P<0.001), respectively, which indicated significant benefits for the LT group compared to the TKI group. There was no significant difference between the LT and TKI groups (P=0.473) regarding the incidence of grade 3 or higher adverse events. Conclusions: This study suggests that the strategic use of additional LT before disease progression is a promising approach for the treatment of EGFR-mutated advanced NSCLC.

Identifying Transmembrane Interactions in Receptor Protein Tyrosine Phosphatase Homodimerization and Heterodimerization.

Receptor protein tyrosine phosphatases (RPTPs) are one of the key regulators of receptor tyrosine kinases (RTKs) and therefore play a critical role in modulating signal transduction. While the structure-function relationship of RTKs has been widely studied, the mechanisms modulating the activity of RPTPs still need to be fully understood. On the other hand, homodimerization has been shown to antagonize RPTP catalytic activity and appears to be a general feature of the entire family. Conversely, their documented ability to physically interact with RTKs is integral to their negative regulation of RTKs, but there is a yet-to-be proposed common model. However, specific transmembrane (TM) domain interactions and residues have been shown to be essential in regulating RPTP homodimerization, interactions with RTK substrates, and activity. Therefore, elucidating the contribution of the TM domains in RPTP regulation can provide significant insights into how these receptors function, interact, and eventually be modulated. This chapter describes the dominant-negative AraC-based transcriptional reporter (DN-AraTM) assay to identify specific TM interactions essential to homodimerization and heteroassociation with other membrane receptors, such as RTKs.

Anti-PTK7 Monoclonal Antibodies Inhibit Angiogenesis by Suppressing PTK7 Function.

PTK7, a catalytically defective receptor protein tyrosine kinase, promotes angiogenesis by activating KDR through direct interaction and induction of KDR oligomerization. This study developed anti-PTK7 monoclonal antibodies (mAbs) to regulate angiogenesis by inhibiting PTK7 function. The effect of anti-PTK7 mAbs on vascular endothelial growth factor (VEGF)-induced angiogenic phenotypes in human umbilical vascular endothelial cells (HUVECs) was examined. Analysis of mAb binding with PTK7 deletion mutants revealed that mAb-43 and mAb-52 recognize immunoglobulin (Ig) domain 2 of PTK7, whereas mAb-32 and mAb-50 recognize Ig domains 6-7. Anti-PTK7 mAbs inhibited VEGF-induced adhesion and wound healing in HUVECs. mAb-32, mAb-43, and mAb-52 dose-dependently mitigated VEGF-induced migration and invasion in HUVECs without exerting cytotoxic effects. Additionally, mAb-32, mAb-43, and mAb-52 inhibited capillary-like tube formation in HUVECs, and mAb-32 and mAb-43 suppressed angiogenesis ex vivo (aortic ring assay) and in vivo (Matrigel plug assay). Furthermore, mAb-32 and mAb-43 downregulated VEGF-induced KDR activation and downstream signaling and inhibited PTK7-KDR interaction in PTK7-overexpressing and KDR-overexpressing HEK293 cells. Thus, anti-PTK7 mAbs inhibit angiogenic phenotypes by blocking PTK7-KDR interaction. These findings indicate that anti-PTK7 mAbs that neutralize PTK7 function can alleviate impaired angiogenesis-associated pathological conditions, such as cancer metastasis.

PTK7, a Catalytically Inactive Receptor Tyrosine Kinase, Increases Oncogenic Phenotypes in Xenograft Tumors of Esophageal Squamous Cell Carcinoma KYSE-30 Cells.

Protein tyrosine kinase 7 (PTK7), a catalytically defective receptor protein tyrosine kinase, is upregulated in tumor tissues and cell lines of esophageal squamous cell carcinoma (ESCC). We showed that PTK7 plays an oncogenic role in various ESCC cell lines. However, its role as an oncogene has not been demonstrated in vivo. Here, we examined the influence of PTK7 on the tumorigenic potential of ESCC KYSE-30 cells, which are known to establish xenograft tumors. Overexpression of PTK7 enhanced the proliferation, adhesion, wound healing, and migration of KYSE-30 cells, and these effects were reversed by the knockdown of PTK7. PTK7 overexpression and knockdown, respectively, increased and decreased the tyrosine phosphorylation of cellular proteins and the phosphorylation of ERK, AKT, and FAK, which are important for cell proliferation, survival, adhesion, and migration. Additionally, PTK7 overexpression and silencing, respectively, increased and decreased the weight, volume, and number of Ki-67-positive proliferating cells in xenograft tumors of KYSE-30 cells. Therefore, we propose that PTK7 plays an important role in the tumorigenesis of ESCC cells in vivo and is a potential therapeutic target for ESCC.

Bone marrow mesenchymal stem cells-derived exosomal microRNA-19b-1-5p reduces proliferation and raises apoptosis of bladder cancer cells via targeting ABL2.

BACKGROUND: Exosomes are involved in intercellular communication via specialized molecular cargo, such as microRNAs (miRNAs). However, the mechanisms underlying exosomal miR-19b-1-5p in bladder cancer remain largely unknown, thus, we aim to investigate the effect of exosomal miR-19b-1-5p on bladder cancer with the involvement of non-receptor protein tyrosine kinase Arg (ABL2). METHODS: miR-19b-1-5p and ABL2 expression were tested in bladder cancer. miR-19b-1-5p inhibition/elevation assays were conducted to determine its role in bladder cancer. Exosomes were extracted from bone marrow mesenchymal stem cells (BMSCs). Exosomes and T24 cells were co-cultured to verify their function in biological characteristics of bladder cancer cells. RESULTS: miR-19b-1-5p was down-regulated while ABL2 was upregulated in bladder cancer. Exosomal miR-19b-1-5p suppressed malignant behaviors of bladder cancer cells, and also inhibited tumor growth in vivo. Up-regulated ABL2 mitigated the effects of miR-19b-1-5p up-regulation on bladder cancer cells. CONCLUSION: BMSCs-derived exosomal miR-19b-1-5p suppresses bladder cancer growth via decreasing ABL2.

Are stem cell marker expression and cd133 analysis relevant to differentiate colorectal cancer? / A expressão de marcadores de células-tronco e a análise do cd133 são relevantes na diferenciação do câncer colorretal?

ABSTRACT Background: CD133 and AXL have been described as cancer stem cell markers, and c-MYC as a key regulatory cellular mechanism in colorectal cancer (CRC). Aim: Evaluate the prognostic role of the biomarkers CD133, AXL and c-MYC and their association with clinicopathologic characteristics in colorectal adenocarcinomas and adenomas. Methods: A total of 156 patients with UICC stage I-IV adenocarcinomas (n=122) and adenomas (n=34) were analyzed. Tissue microarrays (TMA) from primary tumors and polyps for CD133, c-MYC and AXL expression were performed and analyzed for their significance with clinicopathologic characteristics. Results: Poorly differentiated adenocarcinomas and disease progression were independent risk factors for poor overall survival. The median overall survival time was 30 months. Positive CD133 expression (35.9% of all cases), particularly of right-sided CRCs (44.8% of the CD133+ cases), was negatively correlated with death in the univariate analysis, which did not reach significance in the multivariate analysis. c-MYC (15.4% of all cases) was predominantly expressed in advanced-stage patients with distant (non-pulmonary/non-hepatic) metastasis. AXL expression was found only occasionally, and predominantly dominated in adenomas, with less penetrance in high-grade dysplasia. Conclusions: CD133 expression was not associated with inferior overall survival in CRC. While AXL showed inconclusive results, c-MYC expression in primary CRCs was associated with distant metastasis.

RESUMO Racional: CD133 e AXL são descritos na literatura como marcadores de células-tronco tumorais, e c-MYC cumpre papel chave como mecanismo de regulação celular no câncer colorretal (CCR). Objetivo: Avaliar o papel prognóstico dos biomarcadores CD133, AXL e c-MYC e sua associação com características clinicopatológicas de adenocarcinomas e adenomas colorretais. Métodos: Um total de 156 pacientes com adenocarcinomas de estádio UICC I-IV (n=122) e adenomas (n=34) colorretais foram avaliados. Microarranjos teciduais (TMA) dos tumores primários e adenomas foram realizados em busca de expressão de CD133, c-MYC e AXL, com posterior análise de relação significativa com características clinicopatológicas. Resultados: Adenocarcinomas pobremente diferenciados e progressão de doença foram fatores de risco independentes para má sobrevida global. A taxa mediana de sobrevida global foi de 30 meses. Expressão positiva de CD133 (35,9% dos casos), particularmente em cânceres de cólon direito (44,8% dos casos CD133+), correlacionou-se negativamente com óbito na análise univariada, sem significância estatística na análise multivariada. c-MYC (15,4% dos casos) teve predomínio de expressão em pacientes com estádio avançado com metástases distantes (não-pulmonares/não-hepáticas). Expressão de AXL foi pouco encontrada, com predomínio em adenomas, com menor penetrância em displasia de alto grau. Conclusão: Expressão de CD133 não se associou com sobrevida global inferior em CCR. Enquanto AXL demonstrou resultados inconclusivos, expressão de c-MYC em tumores primários se associou-se à metástases à distância.

The catalytically defective receptor protein tyrosine kinase EphA10 promotes tumorigenesis in pancreatic cancer cells.

EphA10 (erythropoietin-producing hepatocellular carcinoma receptor A10) is a catalytically defective receptor protein tyrosine kinase in the ephrin receptor family. Although EphA10 is involved in the malignancy of some types of cancer, its role as an oncogene has not been extensively studied. Here, we investigated the influence of EphA10 on the tumorigenic potential of pancreatic cancer cells. Analysis of expression profiles from The Cancer Genome Atlas confirmed that EphA10 was elevated and higher in tumor tissues than in normal tissues in some cancer types, including pancreatic cancer. EphA10 silencing reduced the proliferation, migration, and adhesion of MIA PaCa-2 and AsPC-1 pancreatic cancer cells. These effects were reversed by overexpression of EphA10 in MIA PaCa-2 cells. Importantly, overexpression and silencing of EphA10 respectively increased and decreased the weight, volume, and number of Ki-67-positive proliferating cells in MIA PaCa-2 xenograft tumors. Further, EphA10 expression was positively correlated with invasion and gelatin degradation in MIA PaCa-2 cells. Moreover, overexpression of EphA10 enhanced the expression and secretion of MMP-9 in MIA PaCa-2 cells and increased the expression of MMP-9 and the vascular density in xenograft tumors. Finally, expression of EphA10 increased the phosphorylation of ERK, JNK, AKT, FAK, and NF-κB, which are important for cell proliferation, survival, adhesion, migration, and invasion. Therefore, we suggest that EphA10 plays a pivotal role in the tumorigenesis of pancreatic epithelial cells and is a novel therapeutic target for pancreatic cancer.

Are stem cell marker expression and cd133 analysis relevant to differentiate colorectal cancer? / A expressão de marcadores de células-tronco e a análise do cd133 são relevantes na diferenciação do câncer colorretal?

ABSTRACT Background: CD133 and AXL have been described as cancer stem cell markers, and c-MYC as a key regulatory cellular mechanism in colorectal cancer (CRC). Aim: Evaluate the prognostic role of the biomarkers CD133, AXL and c-MYC and their association with clinicopathologic characteristics in colorectal adenocarcinomas and adenomas. Methods: A total of 156 patients with UICC stage I-IV adenocarcinomas (n=122) and adenomas (n=34) were analyzed. Tissue microarrays (TMA) from primary tumors and polyps for CD133, c-MYC and AXL expression were performed and analyzed for their significance with clinicopathologic characteristics. Results: Poorly differentiated adenocarcinomas and disease progression were independent risk factors for poor overall survival. The median overall survival time was 30 months. Positive CD133 expression (35.9% of all cases), particularly of right-sided CRCs (44.8% of the CD133+ cases), was negatively correlated with death in the univariate analysis, which did not reach significance in the multivariate analysis. c-MYC (15.4% of all cases) was predominantly expressed in advanced-stage patients with distant (non-pulmonary/non-hepatic) metastasis. AXL expression was found only occasionally, and predominantly dominated in adenomas, with less penetrance in high-grade dysplasia. Conclusions: CD133 expression was not associated with inferior overall survival in CRC. While AXL showed inconclusive results, c-MYC expression in primary CRCs was associated with distant metastasis.

RESUMO Racional: CD133 e AXL são descritos na literatura como marcadores de células-tronco tumorais, e c-MYC cumpre papel chave como mecanismo de regulação celular no câncer colorretal (CCR). Objetivo: Avaliar o papel prognóstico dos biomarcadores CD133, AXL e c-MYC e sua associação com características clinicopatológicas de adenocarcinomas e adenomas colorretais. Métodos: Um total de 156 pacientes com adenocarcinomas de estádio UICC I-IV (n=122) e adenomas (n=34) colorretais foram avaliados. Microarranjos teciduais (TMA) dos tumores primários e adenomas foram realizados em busca de expressão de CD133, c-MYC e AXL, com posterior análise de relação significativa com características clinicopatológicas. Resultados: Adenocarcinomas pobremente diferenciados e progressão de doença foram fatores de risco independentes para má sobrevida global. A taxa mediana de sobrevida global foi de 30 meses. Expressão positiva de CD133 (35,9% dos casos), particularmente em cânceres de cólon direito (44,8% dos casos CD133+), correlacionou-se negativamente com óbito na análise univariada, sem significância estatística na análise multivariada. c-MYC (15,4% dos casos) teve predomínio de expressão em pacientes com estádio avançado com metástases distantes (não-pulmonares/não-hepáticas). Expressão de AXL foi pouco encontrada, com predomínio em adenomas, com menor penetrância em displasia de alto grau. Conclusão: Expressão de CD133 não se associou com sobrevida global inferior em CCR. Enquanto AXL demonstrou resultados inconclusivos, expressão de c-MYC em tumores primários se associou-se à metástases à distância.

Targeted Therapies for the Treatment of Glioblastoma in Adults.

PURPOSE OF REVIEW: Targeted therapies are part of biomarker-driven strategies that exploit actionable molecular targets and have gained traction following survival benefits demonstrated in various systemic malignancies. In glioblastoma, where therapeutic options remain scarce and prognosis poor, targeted therapies offer an attractive treatment alternative and are actively examined in clinical trials. In this review, we summarize the targeted therapies, including traditional small molecule inhibitors and monoclonal antibodies as well as immunotherapeutic approaches that are examined in clinical trials, and discuss the challenges of using them for the treatment of glioblastoma. RECENT FINDINGS: Despite initial speculations, phase II/III trials of targeted therapies in adult patients with glioblastoma have largely failed. Recent trials have focused on improving patient stratification, drug-tissue penetration, and target and compensatory pathway inhibition to optimize treatment response. In contrast to traditional small molecule and monoclonal antibody therapies, cancer immunotherapy may target specific molecular or immune checkpoint target(s) to trigger immune responses against glioblastoma. Early phase clinical trials of immunotherapy have shown encouraging results, and larger randomized trials are ongoing. Targeted therapies are being actively studied in clinical trials. Patients with glioblastoma should be prioritized for clinical trial participation.

Comprehensive Analysis of Copy Number Variations in Kidney Cancer by Single-Cell Exome Sequencing.

Clear-cell renal cell carcinoma (ccRCC) is the most common and lethal subtype of kidney cancer. VHL and PBRM1 are the top two significantly mutated genes in ccRCC specimens, while the genetic mechanism of the VHL/PBRM1-negative ccRCC remains to be elucidated. Here we carried out a comprehensive analysis of single-cell genomic copy number variations (CNVs) in VHL/PBRM1-negative ccRCC. Genomic CNVs were identified at the single-cell level, and the tumor cells showed widespread amplification and deletion across the whole genome. Functional enrichment analysis indicated that the amplified genes are significantly enriched in cancer-related signaling transduction pathways. Besides, receptor protein tyrosine kinase (RTK) genes also showed widespread copy number variations in cancer cells. Our studies indicated that the genomic CNVs in RTK genes and downstream signaling transduction pathways may be involved in VHL/PBRM1-negative ccRCC pathogenesis and progression, and highlighted the role of the comprehensive investigation of genomic CNVs at the single-cell level in both clarifying pathogenic mechanism and identifying potential therapeutic targets in cancers.

Preliminary screening of chemotherapy-resistant genes in esophageal cancer and its clinical significance / 解放军医学杂志

Objective To initially screen the genes associated with chemotherapeutic resistance in esophageal cancer cells, verify the correlation of the genes to the poor prognosis of patients with esophageal cancer, and predict the possible regulatory mechanism of esophageal cancer resistance. Methods The drug sensitivity data of esophageal cancer cell lines were analyzed from GDSC database to screen the cell lines that were relatively sensitive or resistant to both cisplatin and docetaxel. In order to obtain differentially expressed genes, the transcriptome data of the two groups of cell lines were analyzed by the edgeR package according to the following screening criteria: the log2 (fold change) more than –1 or less than1 and P value <0.05. The enrichment cluster analysis of GO biological process was performed in the relatively highly expressed genes of drug-resistant group to identify possible signaling pathways related with drug resistance, and the target genes related to chemotherapeutic resistance were identified based on previous studies. The associations between the expression level of target gene and the clinical pathological features and prognosis of patients were verified in the tissue transcriptome data of esophageal cancer patients. Finally, the proteins interacting with the target gene encoded protein were predicted online using the STRING database, and its possible mechanism of action was analyzed. Results Five cell lines with resistance to both cisplatin and docetaxel and 5 sensitive cell lines were obtained. According to the transcriptome data of the two groups of cell lines, 1097 differentially expressed genes were finally obtained, including 532 highly expressed and 565 low expressed genes in the drug resistant group. The results of GO enrichment analysis for the highly expressed genes indicated that the receptor protein tyrosine kinase pathway was obviously enriched. The expression level of FGR involved in this pathway was significantly correlated with tumor T stage (P=0.021), clinical stage (P=0.007) and prognosis (P=0.0021) of patients with esophageal cancer. In addition, protein interaction analysis indicated that FGR interacted directly or indirectly with multiple proteins, mainly in the form of kinase. Conclusions The receptor protein tyrosine kinase pathway is the most significant signaling pathway associated with chemotherapeutic resistance in esophageal cancer cells. The expression level of FGR in this signaling pathway is significantly correlated with the pathological stage and prognosis of patients with esophageal cancer. FGR may regulate the drug resistance of esophageal cancer cells by phosphorylating downstream target proteins.

Therapeutic Approaches for the Treatment of Epidermal Growth Factor Receptor Mutated Lung Cancer.

Lung cancer surfaces to be the predominant determinant of mortality worldwide constituting 13% and 19% of all new cancer cases and deaths related to cancer respectively. Molecular profiling has now become a regular trend in lung cancer to identify the driver mutations. Epidermal Growth Factor Receptor (EGFR) is the most regular driver mutation encountered in Non-Small Cell Lung Cancer (NSCLC). Targeted therapies are now available for the treatment of EGFR mutant NSCLC. EGFR mutation is more frequently expressed in adenocarcinoma than squamous cell carcinoma. This article presents a detailed molecular insight of the therapeutic approaches for the treatment of EGFR mutant lung cancer. The article delineates molecular mechanism of the drugs that are approved, the drugs that are in clinical trial and the drugs that have not entered a clinical trial but shows promising future in the treatment of EGFR mutant lung cancer. Furthermore, this article provides concise information on relevant combinational or monotherapy clinical trials that have been completed for various approaches.

Anti-angiogenic agents for the treatment of solid tumors: Potential pathways, therapy and current strategies - A review.

Recent strategies for the treatment of cancer, other than just tumor cell killing have been under intensive development, such as anti-angiogenic therapeutic approach. Angiogenesis inhibition is an important strategy for the treatment of solid tumors, which basically depends on cutting off the blood supply to tumor micro-regions, resulting in pan-hypoxia and pan-necrosis within solid tumor tissues. The differential activation of angiogenesis between normal and tumor tissues makes this process an attractive strategic target for anti-tumor drug discovery. The principles of anti-angiogenic treatment for solid tumors were originally proposed in 1972, and ever since, it has become a putative target for therapies directed against solid tumors. In the early twenty first century, the FDA approved anti-angiogenic drugs, such as bevacizumab and sorafenib for the treatment of several solid tumors. Over the past two decades, researches have continued to improve the performance of anti-angiogenic drugs, describe their drug interaction potential, and uncover possible reasons for potential treatment resistance. Herein, we present an update to the pre-clinical and clinical situations of anti-angiogenic agents and discuss the most recent trends in this field.

EGFR mutations cause a lethal syndrome of epithelial dysfunction with progeroid features.

The epidermal growth factor receptor (EGFR) is part of a large family of receptors required for communicating extracellular signals through internal tyrosine kinases. Epidermal growth factor (EGF) signaling is required for tissue development, whereas constitutive activation of this signaling pathway is associated with oncogenic transformation. We identified homozygous c.1283G>A (p.Gly428Asp) mutations in the extracellular domain of EGFR in two siblings. The children were born prematurely, had abnormalities in skin and hair, suffered multisystem organ failure, and died in the neonatal period from intestinal perforation. EGF failed to induce mutated receptor phosphorylation in patient-derived fibroblasts and activation of downstream targets was suppressed. The heterologously expressed extracellular domain was impaired in stability and the binding of EGF. Cells from the affected patient undergo early senescence with accelerated expression of ß-galactosidase and shortened telomeres at all passages when compared to controls. A comparison of homozygous inherited regions from a separate report of a patient from the same ethnic background and EGFR genotype confirms the pathogenicity of EGFR mutations in congenital disease.

Integrin α6ß4 Promotes Autocrine Epidermal Growth Factor Receptor (EGFR) Signaling to Stimulate Migration and Invasion toward Hepatocyte Growth Factor (HGF).

Integrin α6ß4 is up-regulated in pancreatic adenocarcinomas where it contributes to carcinoma cell invasion by altering the transcriptome. In this study, we found that integrin α6ß4 up-regulates several genes in the epidermal growth factor receptor (EGFR) pathway, including amphiregulin (AREG), epiregulin (EREG), and ectodomain cleavage protease MMP1, which is mediated by promoter demethylation and NFAT5. The correlation of these genes with integrin α6ß4 was confirmed in The Cancer Genome Atlas Pancreatic Cancer Database. Based on previous observations that integrin α6ß4 cooperates with c-Met in pancreatic cancers, we examined the impact of EGFR signaling on hepatocyte growth factor (HGF)-stimulated migration and invasion. We found that AREG and EREG were required for autocrine EGFR signaling, as knocking down either ligand inhibited HGF-mediated migration and invasion. We further determined that HGF induced secretion of AREG, which is dependent on integrin-growth factor signaling pathways, including MAPK, PI3K, and PKC. Moreover, matrix metalloproteinase activity and integrin α6ß4 signaling were required for AREG secretion. Blocking EGFR signaling with EGFR-specific antibodies or an EGFR tyrosine kinase inhibitor hindered HGF-stimulated pancreatic carcinoma cell chemotaxis and invasive growth in three-dimensional culture. Finally, we found that EGFR was phosphorylated in response to HGF stimulation that is dependent on EGFR kinase activity; however, c-Met phosphorylation in response to HGF was unaffected by EGFR signaling. Taken together, these data illustrate that integrin α6ß4 stimulates invasion by promoting autocrine EGFR signaling through transcriptional up-regulation of key EGFR family members and by facilitating HGF-stimulated EGFR ligand secretion. These signaling events, in turn, promote pancreatic carcinoma migration and invasion.

Biphasic effect of PTK7 on KDR activity in endothelial cells and angiogenesis.

Protein tyrosine kinase 7 (PTK7) is a member of the defective receptor protein tyrosine kinase family which lacks catalytic activity. Expression of PTK7 is increased in various cancers but its role in carcinogenesis is not well understood. We previously showed that disruption of PTK7 function suppresses VEGF-induced angiogenic phenotypes in HUVECs and mice. Here, we investigated molecular mechanisms for modulating VEGF-induced physiological effects by PTK7. Treatment with a high concentration of extracellular domain of PTK7 (soluble PTK7; sPTK7) or knockdown of PTK7 inhibited VEGF-induced phosphorylation of kinase insert domain receptor (KDR) but did not inhibit phosphorylation of fms-related tyrosine kinase 1 (FLT-1) in HUVECs. PTK7, more specifically sPTK7, interacted with KDR but not with FLT-1 in HUVECs and HEK293 cells. In vitro binding assay showed that sPTK7 formed oligomers with the extracellular domain of KDR (sKDR) up to an approximately 1:3 molar ratio, and vice versa. sPTK7 at lower molar ratios than sKDR enhanced the binding of VEGF to sKDR. At the same or higher molar ratios, it reduced the binding of VEGF to sKDR. Increasing concentrations of sPTK7 or increasing levels of PTK7 expression first increased and then decreased VEGF-induced KDR phosphorylation, migration, and capillary-like tube formation of HUVECs, as well as in vivo angiogenesis. Taken together, our data demonstrates that PTK7 regulates the activity of KDR biphasically by inducing oligomerization of KDR molecules at lower concentrations and by surrounding KDR molecules at higher concentrations.

Effects of laser photocoagulation on serum angiopoietin-1, angiopoietin-2, angiopoietin-1/angiopoietin-2 ratio, and soluble angiopoietin receptor Tie-2 levels in type 2 diabetic patients with proliferative diabetic retinopathy.

AIM: To determine the effects of laser photocoagulation on serum levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), soluble angiopoietin receptor Tie-2 (Tie-2), Ang-1/Ang-2 ratio and vascular endothelial growth factor (VEGF) in patients with type 2 diabetes mellitus (T2DM) and proliferative diabetic retinopathy (PDR). We also explored the role of the Ang/Tie system in PDR. METHODS: 160 patients with T2DM, including 50 patients with non-diabetic retinopathy (NDR), 58 patients with non-proliferative diabetic retinopathy (NPDR), and 52 patients with PDR were enrolled in this study. Serum Ang-1, Ang-2, Tie-2 receptor and VEGF levels were measured using enzyme-linked immunosorbent assays for all patients and were repeated in 26 patients who underwent laser photocoagulation two months after the procedure. RESULTS: The median levels of Ang-2 and VEGF in serum were significantly higher in the NPDR group (4.23 ng/mL and 303.2 pg/mL, respectively) compared to the NDR group (2.67 ng/mL and 159.8 pg/mL, respectively, P<0.01), with the highest level in the PDR group (6.26 ng/mL and 531.2 pg/mL, respectively, P<0.01). The median level of Ang-1 was significantly higher in the NPDR group (10.77 ng/mL) compared to the NDR group (9.31 ng/mL) and the PDR groups (9.54 ng/mL) (P<0.05), while no difference was observed between the PDR and NDR groups. Ang-1/Ang-2 ratio of PDR group was lowest in three groups (1.49 vs 2.69 and 2.90, both P<0.01). The median level of Tie-2 was not significantly different among three groups (P>0.05). Ang-2 was positively correlated with VEGF and Tie-2 in the PDR and NPDR groups (both P<0.05). Among the 26 patients who underwent laser photocoagulation, serum Ang-2 and VEGF levels significantly decreased (both P<0.05), whereas serum Ang-1 level and Ang-1/Ang-2 ratio were weakly increased (P>0.05). The median levels of Ang-2 and VEGF in serum were highest in PDR group, however, Ang-1/Ang-2 ratio of PDR group was lowest in three groups. CONCLUSION: Laser photocoagulation can reduce serum Ang-2 and VEGF levels. The Ang/Tie system and VEGF play an important role in the development and progression of T2DM patients with PDR.

Clinical trials of receptor protein-tyrosine kinase inhabitors in malignant glioma / 国际肿瘤学杂志

The occurrence and development of malignant glioma are closely related to abnormal overexpression and activation of receptor tyrosine kinase (RTK) signal transduction pathways.Targeted therapeutic drugs such as RTK inhibitors,RTK downstream signaling pathway inhibitors and multi-target inhibitors can targeting treat malignant glioma at molecular level,some of which have been investigated in clinical trials and achieved good therapeutic effects.

Detecção de mutações no gene KIT em leucemia mieloide aguda / The detection of KIT mutations in acute myeloid leukemia

OBJETIVO: Descrever a metodologia para detecção de mutações nos éxons 8 e 17 do gene KIT em pacientes portadores de leucemia mieloide aguda, para implementação desse teste no laboratório clínico do Hospital Israelita Albert Einstein. MÉTODOS: Extração do DNA genômico de 54 amostras de sangue periférico ou medula óssea de pacientes com leucemia mieloide aguda para amplificação, por reação em cadeia da polimerase, sequenciamento e análise de fragmentos. RESULTADOS: Dentre as amostras analisadas, quatro apresentaram mutação no éxon 8, duas no éxon 17 e uma amostra apresentou mutação nos dois éxons. CONCLUSÃO: A pesquisa de mutação nos éxons 8 e 17 do gene KIT foi padronizada com sucesso e o teste está em processo de inclusão no menu de exames do laboratório clínico do Hospital Israelita Albert Einstein.

OBJECTIVE: This study describes a new method used in the clinical laboratory at Hospital Israelita Albert Einstein to detect mutations in exons 8 and 17 of the KIT gene in patients with acute myeloid leukemia. METHODS: Genomic DNA extraction was performed on 54 samples of peripheral blood or bone marrow from patients with acute myeloid leukemia. The extracted DNA was amplified by polymerase chain reaction and sequenced, and the fragments were analyzed. RESULTS: Within the analyzed samples, we detected four mutations in exon 8, two mutations in exon 17, and mutations or a double mutation in one sample. CONCLUSION: The tests detecting mutations in exon 8 and 17 on the KIT gene were successfully standardized. The test is now included among the routine diagnostics employed for patients at Hospital Israelita Albert Einstein clinical laboratory.