[Analysis of changes in location before hospital admission, discharge destination and prognostic factors for the survival in hospitals with chronic-phase inpatients].

AIM: To clarify changes in location before hospital admission and discharge destination over the 10-year period of 2010 to 2020 and to identify prognostic factors associated with the survival in hospitals with chronic-phase inpatients. METHODS: The subjects were patients newly admitted to 12 hospitals in 2010 and 2020. The age, sex, location before hospital admission, outcomes at 90 days after admission, discharge destination, and results of 6 biochemical tests at admission were evaluated. A survival analysis was performed for the age, sex, and biochemical tests at admission. RESULTS: We analyzed 8007 newly hospitalized patients. Compared with 2010, there were more hospital admissions from acute-care hospitals and fewer admissions from long-term-care facilities in 2020. In addition, relative to 2010, regarding the outcomes at 90 days after admission, there were more discharges to home and residential facilities in 2020, fewer discharges to long-term-care facilities, and lower mortality rates. In the survival analysis, a multivariate analysis revealed that an elderly age, male sex, low albumin, high total cholesterol, high urea nitrogen, and low serum sodium were poor prognostic factors. These five variables were consistently poor prognostic factors in both 2010 and 2020, and Kaplan-Meier curves showed that the scores were dose-dependent prognostic factors for a poor survival. CONCLUSIONS: The present analysis of pre-admission location and discharge destination in hospitals with chronic-phase patients revealed an elderly age, male sex, high urea nitrogen, low serum sodium, and low albumin at the time of admission to be strong predictors of poor outcomes in these patients.

Impact of Tight Junction Protein ZO-1 and TWIST Expression on Postoperative Survival of Patients with Hepatocellular Carcinoma.

BACKGROUND: Epithelial-mesenchymal transition (EMT) is considered to play a critical role in cancer progression and metastasis. However, the impact of EMT on the prognosis of hepatocellular carcinoma (HCC) is still elusive. In this study, we examined the relationship between the expression of EMT markers and recurrence-free survival (RFS) and overall survival (OS) in HCC patients after hepatic resection. SUMMARY: The mRNA expression of 15 genes related to EMT was assessed by quantitative real-time polymerase chain reaction in cancerous tissues from 72 patients who underwent hepatic resection of HCC between January 2005 and December 2010 at our hospital. The upregulation of TWIST and the downregulation of tight junction protein ZO-1 (TJP1) were significantly associated with shorter RFS as well as OS. Increased levels of TWIST and decreased levels of TJP1 should be predictive markers for poor prognosis in patients with HCC after hepatectomy; those could serve as potential biomarkers for the treatment of HCC. Key Messages: A low level of TJP1 and high level of TWIST expression were prognostic factors predicting HCC after hepatic resection.

SOX4 is a direct target gene of FRA-2 and induces expression of HDAC8 in adult T-cell leukemia/lymphoma.

Previously, we have shown that an AP-1 family member, FRA-2, is constitutively expressed in adult T-cell leukemia/lymphoma (ATL) and, together with JUND, upregulates CCR4 and promotes ATL cell growth. Among the identified potential target genes of FRA-2/JUND was SOX4. Here, we examine the expression and function of SOX4 in ATL. SOX4 was indeed consistently expressed in primary ATL cells. FRA-2/JUND efficiently activated the SOX4 promoter via an AP-1 site. Knockdown of SOX4 expression by small interfering RNA (siRNA) strongly suppressed cell growth of ATL cell lines. Microarray analyses revealed that SOX4 knockdown reduced the expression of genes such as germinal center kinase related (GCKR), NAK-associated protein 1 (NAP1), and histone deacetylase 8 (HDAC8). We confirmed consistent expression of GCKR, NAP1, and HDAC8 in primary ATL cells. We also showed direct activation of the HDAC8 promoter by SOX4. Furthermore, siRNA knockdown of GCKR, NAP1, and HDAC8 each significantly suppressed cell growth of ATL cell lines. Taken together, we have revealed an important oncogenic cascade involving FRA-2/JUND and SOX4 in ATL, which leads to the expression of genes such as GCKR, NAP1, and HDAC8.

FGF3/FGF4 amplification and multiple lung metastases in responders to sorafenib in hepatocellular carcinoma.

UNLABELLED: The response rate to sorafenib in hepatocellular carcinoma (HCC) is relatively low (0.7%-3%), however, rapid and drastic tumor regression is occasionally observed. The molecular backgrounds and clinico-pathological features of these responders remain largely unclear. We analyzed the clinical and molecular backgrounds of 13 responders to sorafenib with significant tumor shrinkage in a retrospective study. A comparative genomic hybridization analysis using one frozen HCC sample from a responder demonstrated that the 11q13 region, a rare amplicon in HCC including the loci for FGF3 and FGF4, was highly amplified. A real-time polymerase chain reaction-based copy number assay revealed that FGF3/FGF4 amplification was observed in three of the 10 HCC samples from responders in which DNA was evaluable, whereas amplification was not observed in 38 patients with stable or progressive disease (P = 0.006). Fluorescence in situ hybridization analysis confirmed FGF3 amplification. In addition, the clinico-pathological features showed that multiple lung metastases (5/13, P = 0.006) and a poorly differentiated histological type (5/13, P = 0.13) were frequently observed in responders. A growth inhibitory assay showed that only one FGF3/FGF4-amplified and three FGFR2-amplified cancer cell lines exhibited hypersensitivity to sorafenib in vitro. Finally, an in vivo study revealed that treatment with a low dose of sorafenib was partially effective for stably and exogenously expressed FGF4 tumors, while being less effective in tumors expressing EGFP or FGF3. CONCLUSION: FGF3/FGF4 amplification was observed in around 2% of HCCs. Although the sample size was relatively small, FGF3/FGF4 amplification, a poorly differentiated histological type, and multiple lung metastases were frequently observed in responders to sorafenib. Our findings may provide a novel insight into the molecular background of HCC and sorafenib responders, warranting further prospective biomarker studies.

Phase I trial of OTS11101, an anti-angiogenic vaccine targeting vascular endothelial growth factor receptor 1 in solid tumor.

OTS11101 is a novel peptide vaccine that acts as an angiogenesis inhibitor by inducing cytotoxic T lymphocyte (CTL) cells that specifically target vascular endothelial cells expressing vascular endothelial growth factor (VEGF) receptor 1. We conducted a phase I study to evaluate the safety, tolerability, maximum tolerated dose, and pharmacodynamic biomarker status of this vaccine. Nine patients with advanced solid tumors received 1.0, 2.0, or 3.0 mg of OTS11101 subcutaneously, once a week in a 28-day cycle. Three patients experienced grade 1 injection site reactions, which were the most frequent adverse events. Grade 2 proteinuria and hypertension each occurred in one patient. As other toxicities were generally mild, the maximum tolerated dose was not reached. Furthermore, we explored the induction of specific activated CTLs, and biomarkers related to angiogenesis. A pharmacodynamics study revealed that induction of specific CTLs was observed for a dose of 2.0 and 3.0 mg. The serum concentrations of soluble VEGF receptor 1 and 2 after vaccination increased significantly compared with baseline. A microarray was performed to give a comprehensive analysis of gene expression, suggesting that OTS11101 vaccination resulted in T cell activation in a clinical setting. In conclusion, OTS11101 was well tolerated in patients up to 3.0 mg once weekly and our biomarker analysis suggested that this anti-angiogenesis vaccine is biologically active.

EGRI and FOSB gene expressions in cancer stroma are independent prognostic indicators for epithelial ovarian cancer receiving standard therapy.

Stromal components interact with cancer cells to promote growth and metastasis. The purpose of this study was to identify genes expressed in stroma, which could provide prognostic information in epithelial ovarian cancer (EOC). Seventy-four patients were included. We performed gene expression profiling and confirmed array data using RT-PCR and immunohistochemistry. By microarray analysis, 52 candidate genes associated with progression free survival (PFS) were identified (P < 0.005). Expression of the early growth response 1 (EGR1) and FBJ murine osteosarcoma viral oncogene homolog B (FOSB) genes was further analyzed. Array data were confirmed by RT-PCR and multivariate analysis demonstrated that both EGR1 and FOSB expression in cancer stroma, and EGR1 expression in cancer are independent prognostic factors in EOC. Immunohistochemically, EGR1 protein is localized in cancer cells and α-smooth muscle actin positive stromal fibroblasts. The EGR1 and FOSB expression in stromal cells and EGR1 expression in cancer cells are prognostic indicators in EOC.

Clinical phase I study of elpamotide, a peptide vaccine for vascular endothelial growth factor receptor 2, in patients with advanced solid tumors.

Targeting of tumor angiogenesis with vaccines is a potentially valuable approach to cancer treatment. Elpamotide is an immunogenic peptide derived from vascular endothelial growth factor receptor 2, which is expressed at a high level in vascular endothelial cells. We have now carried out a phase I study to evaluate safety, the maximum tolerated dose, and potential pharmacodynamic biomarkers for this vaccine. Ten HLA-A*24:02-positive patients with advanced refractory solid tumors received elpamotide s.c. at dose levels of 0.5, 1.0, or 2.0 mg once a week on a 28-day cycle. Five patients experienced an injection site reaction of grade 1 and 2, which was the most frequent adverse event. In the 1.0 mg cohort, one patient experienced proteinuria of grade 1 and another patient developed both hypertension and proteinuria of grade 1. No adverse events of grade 3 or higher were observed, and the maximum tolerated dose was therefore not achieved. The serum concentration of soluble vascular endothelial growth factor receptor 2 decreased significantly after elpamotide vaccination. Microarray analysis of gene expression in PBMCs indicated that several pathways related to T cell function and angiogenesis were affected by elpamotide vaccination, supporting the notion that this peptide induces an immune response that targets angiogenesis in the clinical setting. In conclusion, elpamotide is well tolerated and our biomarker analysis indicates that this anti-angiogenic vaccine is biologically active. Clinical trial registration no. UMIN000008336.

Integrated analysis of whole genome exon array and array-comparative genomic hybridization in gastric and colorectal cancer cells.

Whole genome-scale integrated analyses of exon array and array-comparative genomic hybridization are expected to enable the identification of unknown genetic features of cancer cells. Here, we evaluated this approach in 22 gastric and colorectal cancer cell lines, focusing on protein kinase genes and genes belonging to the cadherin-catenin family. Regarding alternative splicing patterns, several cancer cell lines predominantly expressed isoform 1 of protein kinase A catalytic subunit beta (PRKACB). Paired gastric cancer specimens demonstrated that isoform 1 of PRKACB was a novel cancer-related variant transcript in gastric cancers. In addition, the exon array analysis clearly identified exon 3 or exon 3-4 skipping in catenin beta 1, a short intron insertion with exon 9 skipping in CDH1, and a deletional transcript of CDH13. These abnormal transcripts were shown to have arisen from small genomic deletions. Meanwhile, an integrated analysis of 11 gastric cancer cell lines revealed that four cell lines amplified fibroblast growth factor receptor 2, with truncated forms observed in two of the cell lines. Gene amplification, and not the truncated form, was found to determine the sensitivity to a fibroblast growth factor receptor inhibitor, indicating that our cell line panel might be useful for cell-based evaluations of specific inhibitors. Using an integrated analysis, we identified several abnormal transcripts and genomic alterations in gastric and colorectal cancer cells. Our approach might enable genetic changes to be identified more efficiently, and the present results warrant further investigation using clinical samples and integrated analyses.

Aza-derivatives of resveratrol are potent macrophage migration inhibitory factor inhibitors.

Resveratrol (3, 4', 5-trihydroxy-trans-stilbene), a natural phytoalexin found in grapes and wine, has anti-proliferative activity on human-derived cancer cells. In our study, we used a conventional condensation reaction between aldehydes and amines to provide a number of aza-resveratrol (3, 4', 5-trihydroxy-trans- aza-stilbene) derivatives in an attempt to screen for compounds with resveratrol's action but with increased potency. Aza-resveratrol and its hydroxylated derivative (3, 4, 4', 5-tetrahydroxy-trans- aza-stilbene) showed a more enhanced anti-proliferative effect than resveratrol in an MCF-7 breast carcinoma cell line. To identify the cellular targets of the aza derivatives of resveratrol, we conjugated the latter aza-stilbene compound with epoxy-activated agarose and performed affinity purification. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, was identified as a major target protein in MCF-7 cell lysates using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS). The aza-resveratrol and its hydroxylated derivative, but not resveratrol, were also found to be potent inhibitors of MIF tautomerase activity, which may be associated with their inhibitory effects on MIF bioactivity for cell growth.

Plasma concentrations of angiogenesis-related molecules in patients with pancreatic cancer.

BACKGROUND: Anti-angiogenic agents are now being clinically evaluated for the treatment of pancreatic cancer and a detailed investigation of the angiogenic profile of pancreatic cancer is needed. The aim of this study was to evaluate the plasma concentrations of angiogenesis-related molecules in patients with pancreatic cancer, compared with those with other diseases. METHODS: Plasma samples obtained from 45 patients with pancreatic cancer were analyzed and compared with those from 9 patients with pancreatitis, 16 patients with benign hepatobiliary diseases and 58 patients with colorectal cancers. The plasma levels of angiogenesis-related molecules including angiopoietin-2, follistatin, granulocyte-colony stimulating factor, hepatocyte growth factor, interleukin-8, leptin, platelet-derived growth factor beta polypeptide, platelet endothelial cell adhesion molecule-1 and vascular endothelial growth factor were determined using an antibody suspension bead arrays system. RESULTS: The plasma levels of all the angiogenesis-related molecules were not increased in patients with pancreatic cancer, compared with those with pancreatitis and benign hepatobiliary diseases, whereas the levels of those with colorectal cancer were markedly increased. The plasma interleukin-8 concentration was significantly elevated in patients with distant metastases and was associated with a poor treatment outcome of chemotherapy in patients with pancreatic cancer. CONCLUSIONS: The plasma levels of angiogenesis-related molecules were not elevated in patients with pancreatic cancer, compared with those with benign diseases or colorectal cancer. The plasma interleukin-8 level may be a novel biomarker for the response to chemotherapy in patients with pancreatic cancer and warrants further prospective study.

Enhanced expression of nuclear factor I/B in oxaliplatin-resistant human cancer cell lines.

Oxaliplatin is a third-generation platinum drug that has favorable activity in cisplatin-resistant cells. However, the molecular mechanisms underlying oxaliplatin resistance are not well understood. To investigate the molecular mechanisms involved, resistant cell lines were independently derived from colon cancer (DLD1) and bladder cancer (T24) cells. Oxaliplatin-resistant DLD1 OX1 and DLD1 OX2 cell lines were approximately 16.3-fold and 17.8-fold more resistant to oxaliplatin than the parent cell lines, respectively, and had 1.7- and 2.2-fold higher cross-resistance to cisplatin, respectively. Oxaliplatin-resistant T24 OX2 and T24 OX3 cell lines were approximately 5.0-fold more resistant to oxaliplatin than the parent cell line and had 1.9-fold higher cross-resistance to cisplatin. One hundred and fifty-eight genes commonly upregulated in both DLD1 OX1 and DLD1 OX2 were identified by microarray analysis. These genes were mainly involved in the function of transcriptional regulators (14.6%), metabolic molecules (14.6%), and transporters (9.5%). Of these, nuclear factor I/B (NFIB) was upregulated in all oxaliplatin-resistant cells. Downregulation of NFIB rendered cells sensitive to oxaliplatin, but not to cisplatin. Forced expression of NFIB induced resistance to oxaliplatin, but not to cisplatin. Taken together, these results suggest that NFIB is a novel and specific biomarker for oxaliplatin resistance in human cancers.

Switching addictions between HER2 and FGFR2 in HER2-positive breast tumor cells: FGFR2 as a potential target for salvage after lapatinib failure.

Agents that target HER2 have improved the prognosis of patients with HER2-amplified breast cancers. However, patients who initially respond to such targeted therapy eventually develop resistance to the treatment. We have established a line of lapatinib-resistant breast cancer cells (UACC812/LR) by chronic exposure of HER2-amplified and lapatinib-sensitive UACC812 cells to the drug. The mechanism by which UACC812/LR acquired resistance to lapatinib was explored using comprehensive gene hybridization. The FGFR2 gene in UACC812/LR was highly amplified, accompanied by overexpression of FGFR2 and reduced expression of HER2, and a cell proliferation assay showed that the IC(50) of PD173074, a small-molecule inhibitor of FGFR tyrosine kinase, was 10,000 times lower in UACC812/LR than in the parent cells. PD173074 decreased the phosphorylation of FGFR2 and substantially induced apoptosis in UACC812/LR, but not in the parent cells. FGFR2 appeared to be a pivotal molecule for the survival of UACC812/LR as they became independent of the HER2 pathway, suggesting that a switch of addiction from the HER2 to the FGFR2 pathway enabled cancer cells to become resistant to HER2-targeted therapy. The present study is the first to implicate FGFR in the development of resistance to lapatinib in cancer, and suggests that FGFR-targeted therapy might become a promising salvage strategy after lapatinib failure in patients with HER2-positive breast cancer.

What can and cannot be done using a microarray analysis? Treatment stratification and clinical applications in oncology.

Ten years have passed since the emergence of microarray technology. Recent microarray procedures have provided reliable results on all platforms and have enabled highly reproducible gene expression measurements. Thus, nearly all technical matters regarding microarray measurements are thought to have been resolved. Treatment stratification for molecular-targeted drugs can now be achieved based on the presence of somatic mutations, gene amplification, and/or protein overexpression. However, no clinically available biomarkers have been identified for molecular-targeted drugs using microarray analysis. Microarray data as a database for the gene expressions of clinical samples may be a critical issue, especially for the development of molecular-targeted treatments. In addition, microarray analysis during early-phase clinical trials for molecular-targeted drugs is considered to provide critical information, including proof-of-concept and confirmation of the inhibition of the target molecule. Meanwhile, OncotypeDX(®) and MammaPrint(®) assays have been developed to determine the benefits of chemotherapy for breast cancer patients. These multigene-based assays are commercially available and have shown encouraging results for treatment stratification or decision-making for treatment using cytotoxic drugs in clinical settings. During the development of these assays, numerous samples and efforts were required to create a model using multi-center or inter-group investigations. Based on the success of these models, the development of further assays for determining multigene expressions is likely to increase in the future. In the present article, we introduce our data on mutant epidermal growth factor receptor (EGFR) signaling and amplification of fibroblast growth factor receptor 2 (FGFR2) using microarray analysis, and treatment stratification and clinical applications using gene expression profiles for cancer treatments are discussed.

Role of ZNF143 in tumor growth through transcriptional regulation of DNA replication and cell-cycle-associated genes.

The cell cycle is strictly regulated by numerous mechanisms to ensure cell division. The transcriptional regulation of cell-cycle-related genes is poorly understood, with the exception of the E2F family that governs the cell cycle. Here, we show that a transcription factor, zinc finger protein 143 (ZNF143), positively regulates many cell-cycle-associated genes and is highly expressed in multiple solid tumors. RNA-interference (RNAi)-mediated knockdown of ZNF143 showed that expression of 152 genes was downregulated in human prostate cancer PC3 cells. Among these ZNF143 targets, 41 genes (27%) were associated with cell cycle and DNA replication including cell division cycle 6 homolog (CDC6), polo-like kinase 1 (PLK1) and minichromosome maintenance complex component (MCM) DNA replication proteins. Furthermore, RNAi of ZNF143 induced apoptosis following G2/M cell cycle arrest. Cell growth of 10 lung cancer cell lines was significantly correlated with cellular expression of ZNF143. Our data suggest that ZNF143 might be a master regulator of the cell cycle. Our findings also indicate that ZNF143 is a member of the growing list of non-oncogenes that are promising cancer drug targets.

Bortezomib potentially inhibits cellular growth of vascular endothelial cells through suppression of G2/M transition.

Bortezomib, a selective 26S proteasome inhibitor, has shown clinical benefits against refractory multiple myeloma. The indirect anti-angiogenic activity of bortezomib has been widely recognized; however, the growth-inhibitory mechanism of bortezomib on vascular endothelial cells remains unclear, especially on the cell cycle. Here, we showed that bortezomib (2 nM of the IC(50) value) potently inhibited the cellular growth of human umbilical vascular endothelial cells (HUVECs) via a vascular endothelial growth factor receptor (VEGFR)-independent mechanism resulting in the induction of apoptosis. Bortezomib significantly increased the vascular permeability of HUVECs, whereas a VEGFR-2 tyrosine kinase inhibitor decreased it. Interestingly, a cell cycle analysis using flow cytometry, the immunostaining of phospho-histone H3, and Giemsa staining revealed that bortezomib suppressed the G2/M transition of HUVECs, whereas the mitotic inhibitor paclitaxel induced M-phase accumulation. A further analysis of cell cycle-related proteins revealed that bortezomib increased the expression levels of cyclin B1, the cdc2/cyclin B complex, and the phosphorylation of all T14, Y15, and T161 residues on cdc2. Bortezomib also increased the ubiquitination of cyclin B1 and wee1, but inhibited the kinase activity of the cdc2/cyclin B complex. These protein modifications support the concept that bortezomib suppresses the G2/M transition, rather than causing M-phase arrest. In conclusion, we demonstrated that bortezomib potently inhibits cell growth by suppressing the G2/M transition, modifying G2/M-phase-related cycle regulators, and increasing the vascular permeability of vascular endothelial cells. Our findings reveal a cell cycle-related mode of action and strongly suggest that bortezomib exerts an additional unique vascular disrupting effect as a vascular targeting drug.

Plasma concentrations of VCAM-1 and PAI-1: a predictive biomarker for post-operative recurrence in colorectal cancer.

This prospective study used antibody suspension bead arrays to identify biomarkers capable of predicting post-operative recurrence with distal metastasis in patients with colorectal cancer. One hundred colorectal cancer patients who underwent surgery were enrolled in this study. The median follow-up period was 3.9 years. The pre-operative plasma concentrations of 24 angiogenesis-related molecules were analyzed with regard to the TNM stage and the development of post-operative recurrence. The concentrations of half of the examined molecules (13/24) increased significantly according to the TNM stage (P < 0.05). Meanwhile, a multivariate logistic regression analysis revealed that the concentrations of vascular cell adhesion molecule 1 (VCAM-1) and plasminogen activator inhibitor-1 (PAI-1) were significantly higher in the post-operative recurrence group. The VCAM-1 and PAI-1 model discriminated post-operative recurrence with an area under the curve of 0.82, a sensitivity of 0.75, and a specificity of 0.73. A leave-one-out cross-validation was applied to the model to assess the prediction performance, and the result indicated that the cross-validated error rate was 12.5% (12/96). In conclusion, our results demonstrate that antibody suspension bead arrays are a powerful tool to screen biomarkers in the clinical setting, and the plasma levels of VCAM-1 and PAI-1 together may be a promising biomarker for predicting post-operative recurrence in patients with colorectal cancer.

Amplification of GNAS may be an independent, qualitative, and reproducible biomarker to predict progression-free survival in epithelial ovarian cancer.

OBJECTIVES: The purpose of this study was to identify genes that predict progression-free survival (PFS) in advanced epithelial ovarian cancer (aEOC) receiving standard therapy. METHODS: We performed microarray analysis on laser microdissected aEOC cells. All cases received staging laparotomy and adjuvant chemotherapy (carboplatin+paclitaxel) as primary therapy. RESULTS: Microarray analysis identified 50 genes differentially expressed between tumors of patients with no evidence of disease (NED) or evidence of disease (ED) (p<0.001). Six genes (13%) were located at 8q24, and 9 genes (19.6%), at 20q11-13. The ratio of selected gene set/analyzed gene set in chromosomes 8 and 20 are significantly higher than that in other chromosome regions (6/606 vs. 32/13656, p=0.01) and (12/383 vs. 32/13656, p=1.3 x 10(-)(16)). We speculate that the abnormal chromosomal distribution is due to genomic alteration and that these genes may play an important role in aEOC and choose GNAS (GNAS complex locus, NM_000516) on 20q13 based on the p value and fold change. Genomic PCR of aEOC cells also showed that amplification of GNAS was significantly correlated with unfavorable PFS (p=0.011). Real-time quantitative RT-PCR analysis of independent samples revealed that high mRNA expression levels of the GNAS genes, located at chromosome 20q13, was significantly unfavorable indicators of progression-free survival (PFS). Finally, GNAS amplification was an independent prognostic factor for PFS. CONCLUSIONS: Our results suggest that GNAS gene amplification may be an independent, qualitative, and reproducible biomarker of PFS in aEOC.

SRPX2 is overexpressed in gastric cancer and promotes cellular migration and adhesion.

SRPX2 (Sushi repeat containing protein, X-linked 2) was first identified as a downstream molecule of the E2A-HLF fusion gene in t(17;19)-positive leukemia cells and the biological function of this gene remains unknown. We found that SRPX2 is overexpressed in gastric cancer and the expression and clinical features showed that high mRNA expression levels were observed in patients with unfavorable outcomes using real-time RT-PCR. The cellular distribution of SRPX2 protein showed the secretion of SRPX2 into extracellular regions and its localization in the cytoplasm. The introduction of the SRPX2 gene into HEK293 cells did not modulate the cellular proliferative activity but did enhance the cellular migration activity, as shown using migration and scratch assays. The conditioned-medium obtained from SRPX2-overexpressing cells increased the cellular migration activity of a gastric cancer cell line, SNU-16. In addition, SRPX2 protein remarkably enhanced the cellular adhesion of SNU-16 and HSC-39 and increased the phosphorylation levels of focal adhesion kinase (FAK), as shown using western blotting, suggesting that SRPX2 enhances cellular migration and adhesion through FAK signaling. In conclusion, the overexpression of SRPX2 enhances cellular migration and adhesion in gastric cancer cells. Here, we report that the biological functions of SRPX2 include cellular migration and adhesion to cancer cells.

Epidermal growth factor receptor lacking C-terminal autophosphorylation sites retains signal transduction and high sensitivity to epidermal growth factor receptor tyrosine kinase inhibitor.

Constitutively active mutations of epidermal growth factor receptor (EGFR) (delE746_A750) activate downstream signals, such as ERK and Akt, through the phosphorylation of tyrosine residues in the C-terminal region of EGFR. These pathways are thought to be important for cellular sensitivity to EGFR tyrosine kinase inhibitors (TKI). To examine the correlation between phosphorylation of the tyrosine residues in the C-terminal region of EGFR and cellular sensitivity to EGFR TKI, we used wild-type (wt) EGFR, as well as the following constructs: delE746_A750 EGFR; delE746_A750 EGFR with substitution of seven tyrosine residues to phenylalanine in the C-terminal region; and delE746_A750 EGFR with a C-terminal truncation at amino acid 980. These constructs were transfected stably into HEK293 cells and designated HEK293/Wt, HEK293/D, HEK293/D7F, and HEK293/D-Tr, respectively. The HEK293/D cells were found to be 100-fold more sensitive to EGFR TKI (AG1478) than HEK293/Wt. Surprisingly, the HEK293/D7F and HEK293/D-Tr cells, transfected with EGFR lacking the C-terminal autophosphorylation sites, retained high sensitivity to EGFR TKI. In these three high-sensitivity cells, the ERK pathway was activated without ligand stimulation, which was inhibited by EGFR TKI. In addition, although EGFR in the HEK293/D7F and HEK293/D-Tr cells lacked significant tyrosine residues for EGFR signal transduction, phosphorylation of Src homology and collagen homology (Shc) was spontaneously activated in these cells. Our results indicate that tyrosine residues in the C-terminal region of EGFR are not required for cellular sensitivity to EGFR TKI, and that an as-yet-unknown signaling pathway of EGFR may exist that is independent of the C-terminal region of EGFR.

EGFR mutation up-regulates EGR1 expression through the ERK pathway.

BACKGROUND: DelE746_A750-type EGFR is a constitutively active type of mutation that enhances EGFR signaling. However, the changes in gene expression that occur in mutant EGFR-harboring cells has not been fully studied. MATERIALS AND METHODS: A gene expression analysis of HEK293 cells transfected with wild-type or mutant EGFR was performed focusing on the significant gene. RESULTS: Early growth response 1 (EGR1), a transcription factor, was the most strongly up-regulated gene in mutant EGFR-transfected cells among the genes examined. An increase in EGR1 expression in the mutant EGFR cells was confirmed using RT-PCR or immunoblotting. The expression was up-regulated by EGF stimulation and down-regulated by EGFR-tyrosine kinase inhibitor. In addition, the MEK inhibitor U0126 inhibited EGR1 expression, while the phosphatidylinositol 3-kinase inhibitor LY294002 did not. CONCLUSION: Mutant EGFR constitutively up-regulates EGR1 through the ERK pathway, and its expression is correlated with EGFR signal activation. Findings provide an insight into a target gene of mutant EGFR and further improve the understanding of the oncogenic properties of EGFR.