Prognostic significance of transforming growth factor-alpha in human esophageal carcinoma. Implication for the autocrine proliferation

Linc01014 regulates gefitinib resistance in oesophagus cancer via EGFR-PI3K-AKT-mTOR signalling pathway

This study aimed to explore the underlying mechanism of linc01014 in oesophagus cancer gefitinib resistance. Gefitinib-resistant oesophagus squamous cell carcinoma (ESCC gefitinibR) cell lines were constructed by using different gefitinib treatment in FLO-1, KYAE-1, TE-8 and TE-5 cell lines and confirmed by MTS50 and proliferation assays. Expression of linc01014 was overexpressed/silenced in FLO-1 cells followed by gefitinib treatment, and then, the apoptosis-associated markers Bax and Bcl-2, and PI3KCA in PI3K signalling pathway were determined using Western blotting. MST50 and morphology analyses showed that ESCC gefitinibR cell lines presented obvious gefitinib resistance than their parental ESCC cell lines. ESCC gefitinibR cell lines showed significantly higher proliferation abilities than their parental ESCC cell lines after treating with gefitinib. Overexpression of linc01014 significantly inhibited the apoptosis of FLO-1 cells induced by gefitinib and silencing linc01014 obviously promoted the apoptosis of FLO-1 cells induced by gefitinib. Silencing linc01014 could significantly increase the gefitinib chemotherapy sensitivity of oesophagus cancer via PI3K-AKT-mTOR signalling pathway.

Exosome-mediated transfer of lncRNA PART1 induces gefitinib resistance in esophageal squamous cell carcinoma via functioning as a competing endogenous RNA

BACKGROUND

Currently, resistance to tyrosine kinase inhibitors, such as gefitinib, has become a major obstacle in improving the clinical outcome of patients with metastatic and advanced-stage esophageal squamous cell carcinoma (ESCC). While cell behavior can be modulated by long non-coding RNAs (lncRNAs), the roles of lncRNAs within extracellular vesicles (exosomes) are largely unknown. Therefore, we investigated the involvement and regulatory functions of potential lncRNAs enclosed in exosomes during formation of chemoresistance in human ESCC.

METHODS

Gefitinib-resistant cell lines were established by continuously grafting TE1 and KYSE-450 cells into gefitinib-containing culture medium. LncRNA microarray assay followed by RT-qPCR were used to verify the differential expression of lncRNA Prostate Androgen-Regulated Transcript 1 (PART1) between gefitinib resistant and parental cell lines. RNA fluorescence in situ hybridization (FISH) was used to investigate whether extracellular PART1 could be incorporated into exosomes and transmitted to recipient cells. Subsequently, a series of in vitro assays and a xenograft tumor model were used to observe the functions of lncRNA PART1 in ESCC cells. A signal transduction reporter array, bioinformatics analysis, western blotting, and immunofluorescence were carried out to verify the regulation of PART1 and its downstream Bcl-2 signaling pathway.

RESULTS

lncRNA PART1 was upregulated in gefitinib-resistant cells when compared to parental ESCC cells. It was found that STAT1 can bind to the promoter region of lncRNA PART1, resulting in its activation. Knockdown of lncRNA PART1 potently promoted the gefitinib-induced cell death, while elevated PART1 promoted gefitinib resistance by competitively binding to miR-129 to facilitate Bcl-2 expression in ESCC cells. In addition, extracellular PART1 could be incorporated into exosomes and transmitted to sensitive cells, thus disseminating gefitinib resistance. Clinically, high levels of serum lncRNA PART1 in exosome were associated with poor response to gefitinib treatment in ESCC patients.

CONCLUSIONS

LncRNA PART1 promotes gefitinib resistance by regulating miR-129/Bcl-2 pathway, and may serve as a therapeutic target for ESCC patients.

MicroRNA-1 inhibits tumorigenicity of esophageal squamous cell carcinoma and enhances sensitivity to gefitinib

Dysregulation of microRNAs in various types of human cancer promote or suppress oncogenesis. MicroRNA (miR)-1 was previously revealed to function as a tumor suppressor in prostate cancer cells, and its expression was associated with reduced metastatic potential in lung cancer. The present study investigated the role of miR-1 and its association with phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) in the pathophysiology of esophageal squamous cell carcinoma (ESCC), and analyzed the effects of miR-1 inhibitor or mimics on sensitivity to epidermal growth factor receptor-tyrosine kinase inhibitors, the alterations of cell cycle distribution and apoptosis in ESCC cells. Compared with normal tissues, the level of miR-1 expression was significantly lower and PIK3CA expression was higher in ESCC tissues. The level of miR-1 expression was also inversely associated with the level of PIK3CA mRNA expression. Low miR-1 and high PIK3CA expression levels were strongly associated with lymph node metastasis, and the level of miR-1 expression was negatively associated with clinical Tumor-Node-Metastasis stage. Furthermore, exogenous expression of miR-1 inhibited growth, arrested cell cycle in the G₁ phase and increased apoptosis in ESCC cells, whereas it decreased PIK3CA protein expression levels. Furthermore, overexpression of miR-1 increased the sensitivity of ESCC cells to the anticancer drug, gefitinib. A possible mechanism for this increased sensitivity to gefitinib may be inactivation of the PIK3CA signaling pathway. To the best of our knowledge, this is the first time that the results of the present study demonstrated that miR-1 upregulation may be a potential strategy for the treatment of human ESCC.

Relationship between EGFR over-expression and clinicopathologic characteristics in squamous cell carcinoma of the esophagus: a meta-analysis

Over-expression of epidermal growth factor receptor (EGFR) has been identified as a common feature associated with clinical outcome in many types of cancer, including squamous cell carcinoma of the oesophagus (SCCO). However, the clinical importance of EGFR over-expression in SCCO remains unsettled as conflicting results exist. Therefore we carried out the present meta-analysis of published studies for clarification. A total of 13 studies including 1,150 patients were enrolled. EGFR over-expression was positive in 722 of these cases. With EGFR over-expression, patients had higher depth of invasion, vascular invasion, and poor prognosis. However, expression had no relation with degree of differentiation, histological grade, lymph node metastasis, clinical stage or lymphatic invasion. EGFR over-expression is probably a valuable predictor for the T stage, vascular invasion and OS, and it could be used as a poor prognosis indicator for the esophageal SCC patients. Targeting therapy to EFGR should be considered to the combined treatment in SCCO.

The impact of sphingosine kinase-1 in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) has a high reoccurrence rate and an extremely low survival rate. There is limited availability of effective therapies to reduce the rate of recurrence, resulting in high morbidity and mortality of advanced cases. Late presentation, delay in detection of lesions, and a high rate of metastasis make HNSCC a devastating disease. This review offers insight into the role of sphingosine kinase-1 (SphK1), a key enzyme in sphingolipid metabolism, in HNSCC. Sphingolipids not only play a structural role in cellular membranes, but also modulate cell signal transduction pathways to influence biological outcomes such as senescence, differentiation, apoptosis, migration, proliferation, and angiogenesis. SphK1 is a critical regulator of the delicate balance between proliferation and apoptosis. The highest expression of SphK1 is found in the advanced stage of disease, and there is a positive correlation between SphK1 expression and recurrent tumors. On the other hand, silencing SphK1 reduces HNSCC tumor growth and sensitizes tumors to radiation-induced death.  Thus, SphK1 plays an important and influential role in determining HNSCC proliferation and metastasis. We discuss roles of SphK1 and other sphingolipids in HNSCC development and therapeutic strategies against HNSCC.

Functional single-nucleotide polymorphism of epidermal growth factor is associated with the development of Barrett's esophagus and esophageal adenocarcinoma

Reflux esophagitis (RO) and Barrett's esophagus (BO) can cause esophageal adenocarcinoma (OAC). The esophageal mucosa in the RO-BO-OAC cascade is chronically exposed to gastro-esophageal reflux. Epidermal growth factor (EGF) has an important role in the protection and repair of mucosal damage, and non-physiologic levels are associated with gastrointestinal tumors. The aim is to determine the functional effect of EGF gene polymorphisms on RO, BO and OAC development. A cohort of 871 unrelated Dutch Caucasians consisted of 198 healthy controls, 298 RO patients, 246 BO patients and 129 OAC patients. The frequency of the EGF-production-associated 5'UTR A+61G polymorphism was determined in these four groups. EGF immunohistochemistry was performed on BO biopsies. EGF expression was significantly lower in the G/G genotype compared with the A/G (P=0.008) and A/A (P=0.002) group. The G/G genotype was significantly more prevalent in RO (odds ratios (OR)=2.6; 95% confidence intervals (95% CI): 1.3-5.2), BO (OR=3.0; 95% CI: 1.5-6.2) and OAC (OR=4.1; 95% CI: 1.8-9.7) than in controls. The G allele is associated with reduced EGF expression and increased risk for RO, BO and OAC development. This indicates that reduced mucosal protection resulting from genetically decreased EGF expression enhances esophageal tumor development.

A phase II study of perioperative concurrent chemotherapy, gefitinib, and hyperfractionated radiation followed by maintenance gefitinib in locoregionally advanced esophagus and gastroesophageal junction cancer

BACKGROUND

Concurrent chemoradiotherapy (CCRT) for locoregionally advanced esophageal or gastroesophageal junction cancer produces high locoregional control rates but suboptimal distant metastatic control (DMC) and overall survival. This phase II study added gefitinib (G) to our previously tested CCRT regimen in an effort to improve these outcomes.

METHODS

Eligibility required T3, N1, or M1a esophageal or gastroesophageal junction squamous cell or adenocarcinoma staged by esophageal ultrasound and positron emission tomography/computed tomography. Four-day continuous intravenous infusions of cisplatin (20 mg/m/d) and fluorouracil (1000 mg/m/d) began on day 1 of preoperative radiation (30 Gy and 1.5 Gy bid). Surgery followed in 4 to 6 weeks, and an identical course of CCRT 6 to 10 weeks postoperatively. G 250 mg/d was given with preoperative CCRT for 4 weeks and restarted with postoperative therapy for 2 years. Results were retrospectively compared with our historical series of 93 patients given CCRT without G.

RESULTS

Between April 2003 and July 2006, 80 patients were enrolled. Patient and tumor characteristics were similar to our historical series. G did not increase toxicity except for development of rash in 42 (53%) and diarrhea in 44 (55%) 3-year Kaplan-Meier estimates (G versus non-G treated patients) included: overall survival (42% versus 28%, p = 0.06), DMC (40% versus 32%, p = 0.33), and locoregional control (76% versus 77%, p = 0.74). Intolerance for G maintenance occurred in 48% of patients. Patients who experienced G related diarrhea appeared to have improved outcomes.

CONCLUSIONS

Although G did not worsen CCRT toxicity, maintenance therapy proved difficult. This contemporary cohort of patients enjoyed superior survival, which does not solely reflect a decrease in DMC and merits further investigation.

Phase II study of concurrent chemoradiation in combination with erlotinib for locally advanced esophageal carcinoma

PURPOSE

To investigate the feasibility and efficacy of concurrent chemoradiation in combination with erlotinib for locally advanced esophageal carcinoma.

METHODS AND MATERIALS

Twenty-four patients with locally advanced esophageal carcinoma were treated with concurrent chemoradiotherapy. A daily fraction of 2.0 Gy was prescribed to a total dose of 60 Gy over 6 weeks. Concurrent paclitaxel (135 mg/m(2), d(1)) and cisplatin (20 mg/m(2), d(1-3)) were administered on Day 1 and Day 29 of the radiotherapy. Erlotinib, an oral epidermal growth factor receptor-tyrosine kinase inhibitor, was taken by every patient at the dose of 150 mg daily during the chemoradiotherapy.

RESULTS

The median follow-up of the 24 patients was 18.6 months (range, 7.1-29.6 months). The 2-year overall survival, local-regional control, and relapse-free survival were 70.1% (95% CI, 50.4-90%), 87.5% (95% CI, 73.5-100%), and 57.4% (95% CI, 36.3-78.7%), respectively. During the chemoradiotherapy, the incidences of acute toxicities of Grade 3 or greater, such as leucopenia and thrombocytopenia, were 16.7 % (4/24) and 8.3% (2/24).

CONCLUSIONS

Application of concurrent chemoradiotherapy in combination with erlotinib for locally advanced esophageal carcinoma yielded satisfactory 2-year overall survival and local-regional control. The toxicities were well tolerated.

Association between epidermal growth factor polymorphism and esophageal squamous cell carcinoma susceptibility

Genetic factors are known to be important in the development of esophageal squamous cell carcinoma (ESCC). Epidermal growth factor (EGF) can activate several signaling pathways leading to proliferation, differentiation, and tumorigenesis of epithelial tissues by binding with its receptor. Interindividual variations in EGF production were genetically contributed to EGF +61 G/A polymorphism. The purpose of this study is to investigate the potential association between EGF gene polymorphism and ESCC in a Chinese population. In this study, we analyzed single nucleotide polymorphism of EGF +61 G/A in 158 patients with ESCC and 212 age- and sex-matched controls in a Chinese population using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy and DNA sequencing. The variant genotypes of GA/AA were associated with a significantly decreased risk of ESCC compared with the wild-type homozygote GG (OR = 0.657, 95% CI: 0.434-0.996). However, no significant difference was observed between the EGF +61 G/A polymorphism and the risk of ESCC when the analyses were stratified in terms of age, gender, smoking status, different clinical stage, and lymph node status. The EGF +61 G/A polymorphism is associated with ESCC in a Chinese population. Our data suggests that the EGF gene may play a role in the development of ESCC.

Epidemiology of Human Papilloma Virus (HPV) in Cervical Mucosa

In a worldwide scenario, human papillomavirus (HPV) infection is the second leading cause of cancer-related morbidity and mortality among women due to its very close association with cervical cancer. More than 100 different types of HPV genotypes have been characterized to date. Among these, approximately 24 HPV genotypes specifically infect the genital and oral mucosal system. The mucosal HPVs are most frequently sexually transmitted, and they are responsible for the most common sexually transmitted diseases throughout the world. In a majority of the cases, oncogenic/nononcogenic HPV infections spontaneously clear by themselves without any medical intervention. However, a persistent and long-term HPV infection usually leads to cervical cancer, which remains difficult to treat. In recent years, advance understanding of the structure of HPV and its pathogenesis has led to a variety of new treatments to combat HPV-related diseases, including a Food and Drug Administration-approved HPV vaccine that is very effective in young women. To effectively use this HPV vaccine worldwide, a clear understanding of HPV genotypes in different geographical populations is imperative. In this chapter, we have focused briefly on HPV genotypes and HPV prevalence in the women of different geographical populations.

Esophageal cancer: current and emerging therapy modalities

During the last few years, there has been a gradual increase in treatment options for patients with esophageal malignancies. Several clinical studies have been performed, covering not only radiation and chemotherapy, but also the introduction of novel biological agents into the treatment arsenal. Patients with esophageal carcinoma are now offered second-line and sometimes even third-line treatments, and the number of research protocols is increasing. Despite the newly awakened interest in this malignancy, the overall 5-year survival rate has remained at approximately 10% since the 1980s. This review contains a compilation of available studies of esophageal malignancies and discusses current treatment options as well as newly developed therapies targeted at growth factor receptors.

Expression of Rab5a in hepatocellular carcinoma: Possible involvement in epidermal growth factor signaling

AIM

The Rab subfamily plays a role in intracellular transport. Rab5a is, in particular, involved in receptor-mediated endocytosis. Epidermal growth factor (EGF) is known to induce cell migration and promote invasion and angiogenesis. The EGF receptor (EGFR) is actively internalized upon the addition of EGF. The aim of the present study was to clarify the expression of Rab5a in hepatocellular carcinomas (HCC) and to examine its effect on EGF signaling.

METHODS

The expression of the Rab5a protein in HCC and corresponding non-tumorous tissues from 23 patients with HCC who had undergone surgical resection were analyzed by immunoblotting. A stable transfectant of Rab5a dominant negative (S34N) was established in a human hepatoma cell line, PLC/PRF/5 (PLC/PRF/5/Rab5aDN).

RESULTS

High expression (tumor/non-tumor (T/N) ratios >/= 1) of Rab5a protein in HCC compared to the paired non-tumortissues was recognized in 15 patients (65.2%) of 23 samples. The Rab5a antigen was diffusely expressed in the cytoplasm and membranes of the cancer cells. The membrane-associated Rab5a is also enhanced via overexpression in HCC. The EGF-induced endocytosis of EGFR and the phosphorylation of MAP kinase were inhibited in PLC/PRF/5/Rab5aDN cells. The migration of PLC/PRF/5/Rab5aDN cells induced by EGF was also significantly attenuated.

CONCLUSIONS

These results indicate that the overexpression of Rab5a in HCC may play an important role in EGF signaling.

There is a high prevalence of human papillomavirus infection in American Indian women of the Northern Plains

OBJECTIVES

Cervical cancer is the leading gynecological malignancy worldwide, and the incidence of this disease is very high in American Indian women. Infection with the human papillomavirus (HPV) is responsible for more than 95% of cervical squamous carcinomas. Therefore, the main objective of this study was to analyze oncogenic HPV infections in American Indian women residing in the Northern Plains.

METHODS

Cervical samples were collected from 287 women attending a Northern Plains American Indian reservation outpatient clinic. DNA was extracted from the cervical samples and HPV-specific DNA was amplified by polymerase chain reaction (PCR) using the L1 consensus primer sets. The PCR products were hybridized with the Roche HPV Line Blot assay for HPV genotyping to detect 27 different low- and high-risk HPV genotypes. The Chi-squared test was performed for statistical analysis of the HPV infection and cytology diagnosis data.

RESULTS

Of the total 287 patients, 61 women (21.25%) tested positive for HPV infection. Among all HPV-positive women, 41 (67.2%) were infected with high-risk HPV types. Of the HPV infected women, 41% presented with multiple HPV genotypes. Additionally, of the women infected with oncogenic HPV types, 20 (48.7%) were infected with HPV16 and 18 and the remaining 21 (51.3%) were infected with other oncogenic types (i.e., HPV59, 39, 73). Women infected with oncogenic HPV types had significantly higher (p=0.001) abnormal Papanicolaou smear tests (Pap test) compared to women who were either HPV negative or positive for non-oncogenic HPV types. The incidence of HPV infection was inversely correlated (p<0.05) with the age of the patients, but there was no correlation (p=0.33) with seasonal variation.

CONCLUSIONS

In this study, we observed a high prevalence of HPV infection in American Indian women residing on Northern Plains Reservations. In addition, a significant proportion of the oncogenic HPV infections were other than HPV16 and 18.

Interaction of MT1-MMP and laminin-5gamma2 chain correlates with metastasis and invasiveness in human esophageal squamous cell carcinoma

To gain insights into metastatic mechanisms in esophageal squamous cell carcinoma (ESCC), we established sublines (MLuB1 and MLuC1) with different capacity of spontaneous lung metastasis by subcutaneous injection of a human ESCC cell line (EC 9706) into nude mices. The incidence of the mice with lung metastasis produced by MLuC1 (87%) was significantly higher than that of MLuB1 (22%). The gene expression profiles of the two sublines were compared with cDNA arrays containing 5,000 known genes, and 47 genes were differentially expressed > or =2.0 fold. Laminin-5gamma2 chain (Ln-5gamma2) was one of the up-regulated genes in MLuC1 cells. Proteolytically processed forms of gamma2 are known to promote migration of a multitude of epithelial cells in vitro. Western-blotting analysis revealed that degraded fragments of Ln-5gamma2 and active form of membrane-type matrix metalloproteinase-1 (MT1-MMP) in MLuC1 was significantly higher than those in MLuB1. Expression of MT1-MMP was observed in 60 of 75 Ln-5gamma2-positive carcinoma tissues (80%). Co-expression of the two proteins was significantly associated with depth of invasion (P = 0.012). Moreover, proteolytic fragments of Ln-5gamma2 and active forms of MT1-MMP were frequently found in tumor tissues, whereas in the corresponding normal esophageal tissues there were only intact forms of gamma2 and MT1-MMP. siRNA-mediated silencing of MT1-MMP significantly reduced production of gamma2' and gamma2x in MLuC1 cells and inhibited cell migration. The results suggest that MT1-MMP is an enzyme responsible for Ln-5gamma2 cleavage in ESCC, and interaction between them may play a critical role in promoting invasion and metastasis of human ESCC.

Epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib, and concurrent 5-fluorouracil, cisplatin and radiotherapy for patients with esophageal cancer: a phase I study

This phase I trial investigates the safety of combining radiation, 5-fluorouracil (5-FU) and cisplatin with the epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib, in patients with esophageal carcinoma. From April 2000 to January 2005, 11 patients with squamous or adenocarcinoma of the esophagus were enrolled. Patients received either 50, 100 or 150 mg oral erlotinib/day beginning on the first day of radiation (three patients in each dose cohort). Concurrent cisplatin (75 mg/m2 i.v., days 8 and 36) and 5-FU (1000 mg/m2 i.v., days 8-11 and 36-39) were also given with 50.4 Gy thoracic radiation, delivered at 180 cGy/day, 5 days/week. Toxicity was evaluated using the National Cancer Institute Common Toxicity Criteria (version 3.0). Erlotinib with concurrent 5-FU, cisplatin and thoracic radiation was well-tolerated at 50, 100 and 150 mg/day. The major toxicities were diarrhea (grade 1=18%, grade 2=18%), skin rash (grade 4=54.5%), nausea (grade 1=18%, grade 2=54%, grade 3=9%) and dehydration (grade 3=27%). All patients experienced esophagitis during treatment (grade 1=55%, grade 2=32%, grade 3=9%, grade 4=9%). Two patients were discontinued from the study secondary to non-erlotinib-related toxicities. We conclude that the phase I study demonstrates the safety and tolerability of erlotinib delivered at 150 mg/day with concurrent 5-FU, cisplatin and thoracic radiation. The major toxicities encountered were grade 1-2 diarrhea, grade 1 skin rash, grade 1-3 nausea and grade 3 dehydration. A phase II study is planned.

PTEN/Akt signaling through epidermal growth factor receptor is prerequisite for angiogenesis by hepatocellular carcinoma cells that is susceptible to inhibition by gefitinib

Hepatocellular carcinoma (HCC) is one of the most common tumor-related causes of death worldwide for which there is still no satisfactory treatment. We previously reported the antiangiogenic effect of gefitinib, a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has been used successfully to treat lung cancer. In this study, we investigated the effects of gefitinib on tumor-induced angiogenesis by using HCC cell lines (HCC3, CBO12C3, and AD3) in vitro as well as in vivo. Oral administration of gefitinib inhibited angiogenesis induced by HCC3 and CBO12C3, but not by AD3 in the mouse dorsal air sac model. Production of both vascular endothelial growth factor (VEGF) and chemokine C-X-C motif ligand 1 (CXCL1) by EGF-stimulated HCC was more markedly inhibited by gefitinib in HCC3 and CBO12C3 cells than in AD3 cells. EGF stimulated the phosphorylation of EGFR, Akt, and extracellular signal-regulated kinase 1/2 (ERK1/2) in HCC3 and CBO12C3 cells, whereas EGF stimulated phosphorylation of EGFR and ERK1/2, but not Akt in AD3 cells. In fact, Akt was constitutively activated in the absence of EGF in AD3 cells. Gefitinib inhibited Akt phosphorylation in all three cell lines, but it was about five times less effective in AD3 cells. The concentration of PTEN in AD3 cells was about a half that in HCC3 and CBO12C3 cells. Transfection of HCC3 cells with PTEN small interfering RNA reduced their sensitivity to gefitinib in terms of its inhibitory effect on both Akt phosphorylation and the production of VEGF and CXCL1. In conclusion, effect of gefitinib on HCC-induced angiogenesis depends on its inhibition of the production of angiogenic factors, probably involving a PTEN/Akt signaling pathway.

The enlargement of the hormone immune deprivation concept to the blocking of TGFalpha-autocrine loop: EGFR signaling inhibition

Transforming growth factor alpha (TGFalpha) is a potent ligand of the epidermal growth factor receptor (EGFR). EGFR is frequently over-expressed in epithelial tumors and endogenous ligands, mostly TGFalpha, are frequently co-expressed with EGFR, potentially resulting in autocrine stimulation of tumor cell growth. Therefore, different therapeutic approaches aim for the inactivation of TGFalpha/EGF/EGFR signaling system, but no approach is based on TGFalpha as a target. The principal goal of this work was to assess the potential of an active specific immunotherapy approach to block the TGFalpha/EGFR autocrine loop. For the proof of the concept, a fusion protein between human TGFalpha (hTGFalpha) and P64k protein from Neisseria meningitidis was generated, and its immunogenicity characterized in a mouse model using different adjuvants. All immunogens were effective for the generation of specific humoral responses against hTGFalpha. The inmunodominant epitope of hTGFalpha when immunizing mice with the fusion protein involved the C-loop/C-terminal region. This region includes key residues for hTGFalpha binding to EGFR. The anti-hTGFalpha immune mice sera recognized the natural hTGFalpha precursor in A431 cells and hTGFalpha-transfected 3T3 fibroblasts as revealed by flow cytometry analysis and immunoblotting. They inhibited the binding of (125)I-TGFalpha to the EGFR, EGFR-autophosphorylation, and downstream activation of MAP kinases as well as proliferation of two EGFR-expressing human carcinoma cell lines. These data suggest that EGFR signaling activation by the hTGFalpha autocrine loop may be inhibited in vivo by induction of specifically blocking antibodies. The fusion protein reported in this paper could be a potential immunogen for the development of a new cancer vaccine.

Antitumor effect of gefitinib ('Iressa') on esophageal squamous cell carcinoma cell lines in vitro and in vivo

High expression of epidermal growth factor receptor (EGFR) is thought to be correlated with cell proliferation, invasion, metastasis, resistance to chemoradiotherapy, and poor prognosis in various kinds of human cancers. Blockade of EGFR signal transduction can be a promising strategy for cancer therapy. Approximately 40-70% of esophageal squamous cell carcinomas (ESCCs) show high expression of EGFR. In this study, we examined the antitumor effect of gefitinib, an EGFR tyrosine kinase inhibitor, against ESCC cells in vitro and in vivo. In three ESCC cell lines (TE8, T.T and T.Tn), cell proliferation had been inhibited in a dose-dependent manner and IC(50) values (respectively, 8.49, 18.9 and 17.3muM). Gefitinib inhibited EGF-induced autophosphorylation of EGFR and its downstream signaling pathways, Ras/Raf/MAPK and PI3K/Akt, and caused G(1) arrest of cell cycle and apoptosis confirmed with flow cytometry. We examined the effect of gefitinib on nude mice bearing established TE8 and T.T xenografts. Gefitinib (100 or 200mg/kg once-daily, p.o.) showed antitumor activity in a dose-dependent manner, resulting in a significantly improved survival of treated mice as compared with untreated mice. Immunohistochemical examination of the harvested tumor was performed to examine the status of phosphorylated EGFR, PCNA, Factor VIII and apoptosis. We found inhibition of EGFR phosphorylation, cell cycle arrest (by PCNA staining), decrease of microvessel density (Factor VIII) and induction of apoptosis by TUNEL staining. In conclusion, our findings demonstrate that gefitinib is effective for growth inhibition of ESCC cell lines in vitro and in vivo and suggest that gefitinib may be one of the new therapeutic options for ESSC.

Gastroesophageal reflux and cancer

The causal relationship between GERD and esophageal adenocarcinoma, although unclear just a few decades ago, now is established fairly well. The physiologic changes and the biocellular alterations of the damaged esophageal mucosa are documented better. Despite this knowledge, the dramatic increase in the incidence of esophageal cancer cannot be explained. The absolute risk of esophageal adenocarcinoma arising from GERD is low, and, at present, does not justify population-screening programs. Still, with the notion that adenocarcinoma of the esophagus is an aggressive cancer once documented, important questions still are in need of answers for patients suffering from reflux symptoms. Patients who have reflux disease are not necessarily symptomatic. It remains unclear if patients experiencing reflux symptoms should undergo mandatory endoscopy with biopsies at the esophagogastric junction. Furthermore, metaplasia of the lower esophagus often is not readily recognizable at endoscopy, and only biopsies can document abnormal histology. A severe and prolonged history of reflux always should orient to the possibility of a reflux-related columnar-lined esophagus. Once documented, Barrett's esophagus needs to be seen as a premalignant condition not necessarily leading to adenocarcinoma formation; despite their increased risk of tumor formation, most patients who have Barrett's esophagus die of other causes. During regular endoscopic follow-up, multilevel circumferential biopsies should document the evolution of the histologic changes in the lower esophagus and at the gastroesophageal junction of these patients. It is the only method available to document the appearance of dysplasia. It still is unclear if medicine or surgery provides the best quality of life and the best protection against the development of dysplasia and the possible progression toward adenocarcinoma formation when intestinal metaplasia is present in the esophagus.

Correlation between laminin-5 gamma2 chain and epidermal growth factor receptor expression in esophageal squamous cell carcinomas

OBJECTIVES

Laminin-5 gamma2 chain (LN-5 gamma2) is an extracellular matrix protein that plays an important role in cell migration and tumor invasion. We evaluated the association of LN-5 gamma2 and epidermal growth factor receptor (EGFR) expression in esophageal squamous cell carcinoma (SCC).

METHODS

LN-5 gamma2 and EGFR expression was evaluated in 110 esophageal SCC patients by immunohistochemistry, and was confirmed using esophageal SCC cell lines by Western blot analysis.

RESULTS

LN-5 gamma2 expression in the invasive front of the tumor was correlated with the depth of invasion (p = 0.0001), lymph node metastasis (p = 0.0011) and pathological stage (p = 0.0001). The strong expression of EGFR was also correlated with lymph node metastasis (p = 0.0456) and the pathological stage (p = 0.0055). In patient survival, LN-5 gamma2 positivity and/or strong EGFR expression showed a significantly low survival rate as compared with those with lesser expression of LN-5 gamma2 and EGFR. Immunohistochemically, LN-5 gamma2 expression was significantly correlated with EGFR expression (p < 0.0001). Western blot analysis also confirmed the correlated expression of LN-5 gamma2 and EGFR in SCC cell lines except 2 of the 5 cell lines.

CONCLUSIONS

This study suggests that coexpression of LN-5 gamma2 and EGFR is closely related to the progression and poor prognosis of esophageal SCC.

HER2 overexpression increases sensitivity to gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, through inhibition of HER2/HER3 heterodimer formation in lung cancer cells

Gefitinib (Iressa), an epidermal growth factor receptor targeting drug, has been clinically useful for the treatment of patients with non-small cell lung cancer (NSCLC). Gefitinib is currently being applied in clinical studies as either a monotherapy, or as part of a combination therapy against prostate, head and neck, gastric, breast, and colorectal tumors. However, success rates vary between different tumor types, and thus it is important to understand which molecular target(s) are responsible for limiting the therapeutic efficacy of the drug. In this study, we ask whether expression of HER2 affects sensitivity to gefitinib in human lung cancer cells. We established two clones, LK2/HER2-32 and LK2/HER2-57, by transfecting HER2 cDNA into LK2, a NSCLC line with a low expression level of HER2. We observed no mutations in exons 18, 19, and 21 of EGFR gene in LK2, LK2/mock- and two HER2-trasfectants when we observed in-frame deletion mutations (E746-A750) adjacent to K745 in a gefitinib-sensitive NSCLC cell line, PC9. These LK2/HER2-32 and LK2/HER2-57 were much more sensitive to the cytotoxic effects of gefitinib than the parental LK2 lines. Treatment with 0.5 to 1 micromol/L gefitinib specifically blocked Akt activation in both HER2-transfectant lines, but not in the parental LK2 cells. Extracellular signal-regulated kinase-1/2 activation, however, was not blocked by gefitinib up to 10 micromol/L in either the parent or transfectant lines. Gefitinib was also shown to induce cell cycle arrest in the G1-S phase, and an accompanying increase of p27Kip1 was observed. LK2/HER2 transfectants showed constitutive formation of HER2/HER3 heterodimer, which were seen to associate with a regulatory subunit of phosphoinositide-3-kinase, p85alpha, when active. Treatment of LK2/HER2 cells with gefitinib markedly decreased the formation of HER2/HER3 heterodimers, HER3 basal phosphorylation, and the association of p85alpha with HER3. This study is the first to show that under basal growth conditions, HER2 sensitizes low-EGFR NSCLC cell lines to growth inhibition by gefitinib.

Efficacy of epidermal growth factor receptor-targeted molecular therapy in anaplastic thyroid cancer cell lines

Anaplastic thyroid cancer is one of the most aggressive human malignancies and the outcomes of conventional therapy have been far from satisfactory. Recently, epidermal growth factor receptor (EGFR)-targeted therapy has been introduced as an alternative therapeutic strategy for highly malignant cancers. This study was undertaken to investigate the expression of EGFR in anaplastic thyroid cancer cell lines, and to explore the potential of therapies targeting EGFR as a new therapeutic approach. EGFR was universally expressed in anaplastic cancer cell lines at a variety of levels. Specific EGFR stimulation with epidermal growth factor showed significant phosphorylation of ERK1/2 and Akt, and resulted in marked growth stimulation in an anaplastic thyroid cancer cell line, which highly expressed EGFR. This EGFR-transmitted proliferation effect of the cancer cell line was completely inhibited by gefitinib, an EGFR tyrosine kinase inhibitor. Moreover, growth of xenografts inoculated in mice was inhibited in a dose-dependent manner with 25–50 mg kg⁻¹ of gefitinib administrated orally. Inhibition of EGFR-transmitted growth stimulation by gefitinib was clearly observed in anaplastic thyroid cancer cell lines. Our results suggested that EGFR-targeted therapy, such as gefitinib, might be worth further investigation for the treatment of anaplastic thyroid cancer.

Enhancement of tumor radioresponse by combined treatment with gefitinib (Iressa, ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor, is accompanied by inhibition of DNA damage repair and cell growth in oral cancer

Molecular blockade of EGFR with either an EGFR MAb or an EGFR TKI enhances the radiosensitivity of human SCCs. In the present study, we investigated whether treatment with the EGFR TKI gefitinib (Iressa, ZD1839) improves the response to radiotherapy in the OSCC cell lines HSC2 and HSC3. We examined potential mechanisms that may contribute to the enhanced radiation response induced by gefitinib. Growth inhibition was observed in vitro with radiation or gefitinib. A cooperative antiproliferative effect was obtained when cancer cells were treated with radiation followed by gefitinib. Cells treated with a combination of radiation and gefitinib arrested in G(1) and G(2)-M phases, with a decrease in the S-phase population. While radiation alone did not significantly affect MEK1/2 and p38 MAPK autophosphorylation, the combination of gefitinib and radiation completely inhibited the downstream signaling of EGFR. Results from DNA damage repair analysis in cultured OSCC cells demonstrated that gefitinib had a strong inhibitory effect on DNA-PKc pathways after radiation. Tumor xenograft studies demonstrated that the combination of gefitinib and radiation caused growth inhibition and tumor regression of well-established OSCC tumors in athymic mice; tumor volume was reduced from 1,008.2 to 231.4 mm(3) in HSC2 cells (p < 0.01) and from 284.2 to 12.4 mm(3) in HSC3 cells (p < 0.01). Immunohistochemical analysis of OSCC xenografts revealed that gefitinib caused a striking decrease in tumor cell proliferation when combined with radiotherapy. Overall, we conclude that gefitinib enhances tumor radioresponse by multiple mechanisms that may involve antiproliferative growth inhibition and effects on DNA repair after exposure to radiation.

Gefitinib ('Iressa'), an epidermal growth factor receptor tyrosine kinase inhibitor, mediates the inhibition of lymph node metastasis in oral cancer cells

High expression of epidermal growth factor receptor (EGFR) is frequently observed in many solid tumor types including oral squamous cell carcinomas (OSCC). This study investigated whether treatment with gefitinib ('Iressa'), an EGFR-tyrosine kinase inhibitor, would inhibit the metastatic spread in OSCC cells. This was evaluated using orthotopic xenografts of highly metastatic OSCC. Metastasis was observed in six of 13 gefitinib treated animals (46.2%), compared with all of 12 control animals (100%). After exposure to gefitinib, OSCC cells showed a marked reduction in cell adhesion ability to fibronectin and in the expression of integrin alpha3, alphav, beta1, beta4, beta5 and beta6.

Gefitinib (‘Iressa’, ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor, up-regulates p27KIP1 and induces G1 arrest in oral squamous cell carcinoma cell lines

High expression of epidermal growth factor receptor (EGFR) is frequently observed in many solid tumor types including oral squamous cell carcinomas (OSCC). Recently, the results of preclinical studies and early clinical trials targeting the EGFR have shown evidence of the activity. In this study, gefitinib ('Iressa', ZD1839), an EGFR-tyrosine kinase inhibitor, inhibited cell proliferation and upregulated p27KIP1 in OSCC cells. Growth inhibition was observed in OSCC xenografts when mice were treated with gefitinib in vivo. A flow cytometric analysis demonstrated that treatment with gefitinib induced accumulation in G1 phase, accompanied by a decrease in the percentage of cells in S phase. Apoptosis was not seen in this study. Cell growth was inhibited by an increase of the cell cycle inhibitor p27KIP1 and a decrease of its ubiquitin ligase subunit Skp2.

Autocrine stimulation by insulin-like growth factor I is involved in the growth, tumorigenicity and chemoresistance of human esophageal carcinoma cells

Insulin-like growth factor I (IGF-I) receptor (IGF-IR)-mediated signals are known to be involved in cell growth and transformation and prevention of apoptosis. In this study, we demonstrated the coexpression of IGF-I and IGF-IR in human esophageal carcinoma tissues. We also demonstrated the IGF-I autocrine system in esophageal carcinoma cell lines. Both the CE48T/VGH and CE81T/VGH cell lines showed proliferative responses to IGF-I stimulation. Autokinase activity of IGF-IR in these cells can be triggered by the exogenous addition of IGF-I. In addition, an IGF-I peptide antagonist, JB1, specifically inhibited ligand-induced receptor autophosphorylation in a dose-dependent manner. Under serum-free conditions, JB1 also reduced the degree of IGF-IR phosphorylation and cell numbers. Furthermore, the addition of JB1 decreased the number of CE81T/VGH colonies formed in methyl cellulose agar and the size and the incidence of tumors which grew in mice with severe combined immunodeficiency. These results imply that an IGF-I autocrine system in human esophageal carcinoma cells could stimulate tumor growth. Finally, we found that IGF-I prevented the apoptosis of CE81T/VGH cells induced by chemotherapeutic drugs, such as cisplatin, 5-fluorouracil and camptothecin. Thus, interruption of IGF-IR function may provide a way to retard tumor growth and increase the sensitivity of esophageal carcinoma to chemotherapy.

Enhancement of Radiosensitivity in Head and Neck Cancer Cells by ZD1839 (‘IRESSA’), A Selective Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Overexpression of epidermal growth factor receptor (EGFR) is frequently observed in many solid tumor types, including head and neck squamous cell carcinomas (HNSCC). Recent laboratory experiments have demonstrated that high EGFR levels correlate with increased tumor resistance to radiation. This study investigated the relationship between EGFR expression levels and radiosensitivity in 5 HNSCC cell lines (HSC2, HSC3, HSC4, SCC25, and Ca9-22) and whether treatment with ZD1839 ('Iressa'), a selective EGFR-tyrosine kinase inhibitor (TKI), would improve tumor cell response to radiotherapy. ZD1839 suppressed the growth of HNSCC cell lines in a dose- and time-dependent manner. Radiosensitivity of these HNSCC cell lines, assessed by a clonogenic survival assay, differed greatly and the expression of EGFR varied. EGFR expression levels (EGFR numbers/cell) correlated with increased tumor resistance to radiation (f[x]= 4.54 X, R2 = 0.715; f[x]: EGFR numbers/cell, X: radiosensitivity; D10). Following exposure of the HNSCC cells to 1.0 microM ZD1839 and radiation (0-10 Gy), greater than additive growth inhibitory effects were observed. These results suggest that ZD1839 could enhance tumor radiosensitivity and inhibit tumor growth after radiation, indicating that this combination could have clinical potential in the treatment of patients with head and neck cancer.

Significant host- and tumor-related factors for predicting prognosis in patients with esophageal carcinoma

OBJECTIVE

To identify clinically useful parameters obtainable before treatment of predicting clinical outcomes in patients with esophageal carcinoma.

SUMMARY BACKGROUND DATA

Various factors regarding the biologic state of tumors or the nutritional state of patients have been individually reported to correlate with prognosis. Reliable estimates of life expectancy before treatment are important, and consideration needs to be given not only to tumor-related but also to host-related factors in patients with esophageal carcinoma.

METHODS

The following clinicopathological factors were retrospectively analyzed in 356 consecutive patients with surgical treatment: sex; age; serum C-reactive protein (CRP); proportion of lymphocytes; body weight changes; serum albumin; clinical TNM staging; tumor location; serum squamous cell-related antigen; serum carcinoembryonic antigen; and histology. Factors related to prognosis were evaluated by using univariate and multivariate analyses.

RESULTS

According to univariate analysis, significant differences in survival were found for sex, serum CRP, proportion of lymphocytes, body weight change, serum albumin, serum squamous cell-related antigen, and clinical TNM staging. Multivariate analysis demonstrated that CRP levels (P = 0.0285), body weight change (P = 0.0165), and clinical TNM staging (P = 0.0008) displayed independent correlations to prognosis. When serum CRP elevation, body weight loss, and clinical TNM staging III and IV were scored as a combined index, the total score (prognostic index for esophageal cancer, PIEC) demonstrated a good stratification value for prognosis. Moreover, PIEC was superior to the conventional clinical TNM staging by the likelihood ratio test.

CONCLUSIONS

PIEC based on serum CRP, body weight change, and clinical TNM staging before treatment offers a very simple and informative method for predicting the prognosis of patients with esophageal carcinoma.

Role of molecular biology in the follow-up of patients who have Barrett's esophagus

At present, the follow-up of patients who have Barrett's esophagus (BE) should occur within the setting of an endoscopic biopsy surveillance program and with the frequency of surveillance as proposed by the American College of Gastroenterology. In the future, patients who have BE will be further stratified according to their risk for progression to invasive carcinoma. This stratification will permit the development of more rational surveillance programs. Models that incorporate epidemiologic risk factors, reflux symptoms, and endoscopic and histologic findings will likely include panels of biomarkers for further stratification of patients as low, intermediate, or high risk. Therefore, the challenge over the next decade will be to define the role of molecular markers in endoscopic surveillance strategies and to identify additional clinically relevant molecular markers for prognosis as intermediate markers for chemoprevention and as molecular targets for novel gene therapies.

Expression and prognostic value of epidermal growth factor receptor, transforming growth factor-alpha, and c-erb B-2 in nephroblastoma

BACKGROUND

Wilms tumor is one of the most common solid tumors in children. A transforming growth factor-alpha (TGF-alpha)/epidermal growth factor receptor (EGF-R) autocrine loop plays an important role in tumor growth. Abnormal expression of TGF-alpha, EGF-R and c-erb B-2 has been demonstrated in several human malignancies.

METHODS

The immunohistochemical expression of TGF-alpha, EGF-R, and c-erb B-2 was studied in paraffin material of 62 clinical Wilms tumors. Patients had a mean follow-up of 5.7 years.

RESULTS

Generally, TGF-alpha, EGF-R, and c-erb B-2 were expressed in tissue of the normal kidney and at variable levels in the three cell types of Wilms tumor, i.e., blastemal, epithelial, and stromal cells. Immunoreactive blastema cells were found in 48%, 44%, and 34% of tumors for TGF-alpha, EGF-R, and c-erb B-2, respectively. It was found that TGF-alpha, EGF-R, and c-erb B-2 blastemal and epithelial expression gradually increased from T1 to T3. The blastemal expression of TGF-alpha was statistically significantly correlated with clinicopathologic stages. Both univariate and multivariate analysis showed that blastemal TGF-alpha expression was indicative for clinical progression, but neither blastemal TGF-alpha, nor EGF-R or c-erb B-2 expression correlated with patients survival. Epithelial staining was of no prognostic value. The simultaneous expression of TGF-alpha/EGF-R was indicative for clinical progression at univariate level.

CONCLUSIONS

Increased expression of TGF-alpha in the blastemal part of Wilms tumor correlated with tumor classification and clinical progression. These findings suggest that significant expression of TGF-alpha and EGF-R may play a role in promoting transformation and/or proliferation of Wilms tumor, perhaps by an autocrine mechanism. Therefore, their expression may be of value in identifying patients at high risk of tumor recurrence.

Tumor marker expression is predictive of survival in patients with esophageal cancer

BACKGROUND

This study was designed to determine the prognostic value of immunohistochemical tumor marker expression in a population of patients with node-negative esophageal cancer treated with complete resection alone.

METHODS

Resection specimens were collected from 61 patients with node-negative T1 (n = 31), T2 (n = 14), and T3 (n = 16) esophageal cancer. A panel of 10 tumor markers was chosen for immunohistochemical analysis, based on associations with differing oncologic mechanisms: apoptosis (p53), growth regulation (transforming growth factor-alpha, epidermal growth factor receptor, and Her2-neu), angiogenesis (factor VIII), metastatic potential (CD44), platinum resistance (p-glycoprotein and metallothionein), 5-fluorouracil resistance (thymidylate synthetase), and carcinogenic detoxification (glutathione S-transferase-pi).

RESULTS

Complete resection was performed in all patients (44 adenocarcinoma, 17 squamous cell carcinoma), with no operative deaths. Multivariable analysis demonstrated a significant relationship between cancer-specific death and the following variables: low-level P-gp expression (p = 0.004), high-level expression of p53 (p = 0.04), and low-level expression of transforming growth factor-alpha (p = 0.03). In addition, the number of involved tumor markers present was strongly predictive of negative outcome (p = 0.0001).

CONCLUSIONS

This study supports the prognostic value of immunohistochemical tumor markers, specifically the expression pattern of P-gp, p53, and transforming growth factor-alpha, in patients with esophageal carcinoma treated with complete resection alone.

Significance of preoperative elevation of serum C-reactive protein as an indicator of prognosis in esophageal carcinoma

BACKGROUND

Preoperative elevation of serum C-reactive protein (CRP) has been reported to be a prognostic indicator in gastric carcinoma and colorectal carcinoma. The aim of this study was to establish the significance of preoperative elevation of serum CRP as an indicator of prognosis in patients with esophageal carcinoma.

METHODS

Two hundred sixty-two patients with esophageal carcinoma who had been treated by esophageal resection and reconstruction of digestive tracts were evaluated, excluding patients with neoplasms in other organs. Preoperative serum CRP was measured, and the relation between the elevation of serum CRP and the clinicopathological factors and prognosis of the patients was investigated.

RESULTS

The mean size of the tumors and the proportions of lymph node metastasis and lymphatic invasion were significantly larger in patients with preoperative elevation of serum CRP than in patients without preoperative elevation of serum CRP (5.8 +/- 2.5 cm versus 4.8 +/- 2.5 cm, P <0.01, 59.5% versus 35.4%, P <0.001, and 35.7% versus 23.6%, P <0.05, respectively). 1-, 3-, and 5-year survival rates in patients with preoperative elevation of serum CRP (60.6%, 18.4%, and 11.5%, respectively) were significantly lower than those in patients without preoperative elevation of serum CRP (88.7%, 70.9%, and 68.4%, respectively; P <0.0001). Multivariate analysis demonstrated that the preoperative elevation of serum CRP was an independent prognostic factor in esophageal carcinoma (P <0.0001).

CONCLUSIONS

The preoperative serum elevation of CRP can be a marker of the malignant potential of the tumor and an independent prognostic indicator in esophageal carcinoma.

Genistein, a tyrosine kinase inhibitor, enhanced radiosensitivity in human esophageal cancer cell lines in vitro: possible involvement of inhibition of survival signal transduction pathways

PURPOSE

The effect of genistein, a tyrosine kinase inhibitor, on radiosensitivity was examined, especially focusing on "survival signal transduction pathways."

METHODS AND MATERIALS

Two human esophageal squamous cell cancer cell lines, TE-1 (p53, mutant) and TE-2 (p53, wild), were used. Radiosensitivity was determined by clonogenic assay, and activation of survival signals was examined by Western blot.

RESULTS

Genistein (30 microM) greatly enhanced radiosensitivity in these cell lines by suppressing radiation-induced activation of survival signals, p42/p44 extracellular signal-regulated kinase and AKT/PKB. Significant increase in the percentage of apoptotic cells and increased poly[ADP-ribose] polymerase cleavage were observed in TE-2, but not in TE-1 even after combination of genistein with irradiation. In terms of changes in expression of p53-related proteins, increase in expression of Bax and decrease in that of Bcl-2 were observed in TE-2 but not in TE-1, suggesting that the main mode of cell death induced by genistein in a cell line with wild type p53 differed from that with mutant p53.

CONCLUSIONS

This study suggested that survival signals, including p42/p44 ERK and AKT/PKB, may be involved in determining radiosensitivity, and genistein would be a potent therapeutic agent that has an enhancing effect on radiation.

Expression of syndecan-1 is common in human lung cancers independent of expression of epidermal growth factor receptor

In order to determine syndecan-1 expression in lung cancer, we examined 115 lung cancer specimens and 17 lung cancer cell lines. Syndecan-1 was immunohistochemically stained with a polyclonal antibody in 115 paraffin-embedded specimens; 84 cases out of 97 non-small cell lung cancer (NSCLC) and eight cases out of 18 small cell lung cancer (SCLC) were positively stained. Simultaneously, epidermal growth-factor receptor (EGFR) was stained; 47 cases out of 97 NSCLC and one case of 18 SCLC were positively stained. No significant correlation was shown between EGFR and syndecan-1 expression (P=0.68). Syndecan-1 mRNA was detectable in 16 of 17 lung cancer cell lines and EGFR mRNA in nine of 17. Eight cell lines had syndecan-1 mRNA as well as EGFR mRNA. PR-39 (1 microM) and 80 pM transforming growth factor-beta(1) (TGF-beta(1)), did not increase expressions of syndecan-1 mRNA and EGFR in five lung cancer cell lines. We concluded that lung cancer had detectable syndecan-1; however, expression of syndecan-1 protein did not correlate with survival time of lung cancer patients.

Pharmacokinetics and Tolerability of the Orally Active Selective Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor ZD1839 in Healthy Volunteers

OBJECTIVE

To investigate the pharmacokinetics and tolerability of ZD1839 (Iressa), an orally active selective epidermal growth factor receptor-tyrosine kinase inhibitor, in healthy volunteers.

DESIGN

Two randomised, double-blind, placebo-controlled, parallel-group studies of pharmacokinetics and tolerability, followed by a nonblind, randomised, 2-period crossover study to assess the effect of food on bioavailability.

SETTING

Two centres in the UK.

STUDY PARTICIPANTS

Healthy male volunteers aged between 18 and 62 years.

INTERVENTIONS

The first study investigated the pharmacokinetics and tolerability of ascending single oral doses of ZD1839 (1 to 75mg). The second study investigated the pharmacokinetics and tolerability of multiple doses of ZD1839 (100mg once daily for 3 days). The third study investigated the effect of food on the bioavailability of a single 50mg dose of ZD1839.

OUTCOME MEASURES AND RESULTS

Peak plasma drug concentrations (Cmax) of ZD 1839 occurred between 3 and 7 hours after administration. Cmax and area under the concentration-time curve (AUC) were dose-proportional from 10 to 100mg. The terminal elimination half-life (t1/2beta) was 28 hours (range 12 to 51 hours). Cmax was reduced by 34% and AUC by 14% by ingestion of food; t1/2beta was not affected. Urinary recovery of ZD1839 was <0.5%, indicating that this was not a major route of elimination. The pharmacokinetics of ZD1839 during administration of multiple doses could be predicted from day 1 values. There were no serious adverse events or withdrawals, and the frequency of adverse events was similar that with placebo.

CONCLUSIONS

These data support the further clinical investigation of ZD 1839. The elimination half-life suggests that once daily oral administration is appropriate.

TGF-alpha antisense gene therapy inhibits head and neck squamous cell carcinoma growth in vivo

Unlike normal mucosal squamous epithelial cells, head and neck squamous cell carcinomas (HNSCCs) overexpress TGF-alpha mRNA and protein which is required to sustain the proliferation of HNSCC cells in vitro. To determine whether TGF-alpha expression contributes to tumor growth in vivo, cationic liposome-mediated gene transfer was used to deliver an antisense expression construct targeting the human TGF-alpha gene into human head and neck tumor cells, grown as subcutaneous xenografts in nude mice. The TGF-alpha antisense gene was immediately detected in the cytoplasm of the tumor cells, translocated to the nucleus by 12 h and remained localized to the nucleus for up to 3 days. Direct inoculation of the TGF-alpha antisense (but not the corresponding sense) construct into established HNSCC tumors resulted in inhibition of tumor growth. Sustained antitumor effects were observed for up to 1 year after the treatments were discontinued. Down-modulation of TGF-alpha was accompanied by increased apoptosis in vivo. These experiments indicate that interference with the TGF-alpha/EGFR autocrine signaling pathway may be an effective therapeutic strategy for cancers which overexpress this ligand/receptor pair.

Akt/protein kinase B isoforms are differentially regulated by epidermal growth factor stimulation

Overexpression of epidermal growth factor receptor (EGFR) in certain cancers is well established. There is growing evidence that epidermal growth factor (EGF) activates Akt/protein kinase B (PKB) in a phosphoinositide 3-OH kinase (PI3K)-dependent manner, but it is not yet clear which Akt isoforms are involved in this signal transduction pathway. We investigated the functional regulation of three Akt isoforms, Akt1/PKBalpha, Akt2/PKBbeta, and Akt3/PKBgamma, in esophageal cancer cells where EGFR is frequently overexpressed. Upon EGF simulation, phosphorylation of Akt1 at the Ser-473 residue was remarkably induced. This result was corroborated by in vitro Akt kinase assays using glycogen synthase kinase 3beta as the substrate. PI3K inhibitors, wortmannin or LY294002, significantly blocked the Akt kinase activity induced by EGF. Akt2 activity was evaluated by electrophoretic mobility shift assays. Robust activation of Akt2 by EGF was observed in some cell lines in a PI3K-dependent manner. EGF-induced Akt3 activation was demonstrated by Ser-472 phosphorylation of Akt3 but in a restrictive fashion. In aggregate, EGF-mediated activation of Akt isoforms is overlapping and distinctive. The mechanism by which EGFR recruits the PI3K/Akt pathway was in part differentially regulated at the level of Ras but independent of heterodimerization of EGFR with either ErbB2 or ErbB3 based upon functional dissection of pathways in esophageal cancer cell lines.

Clinical application of malignancy potential grading as a prognostic factor of human esophageal cancers

BACKGROUND

Various biologic markers have been reported to be prognostic factors in human esophageal cancers. In the current study, we established a new tumor-grading system representing the malignancy potential of cancer cells and compared it with the clinical-stage system.

METHODS

Tumor samples from 77 patients with squamous cell carcinoma of the esophagus were immunohistochemically evaluated for the expression of 10 molecules: the cell cycle-related molecules of cyclin D1, Rb, p16INK4, p27KIP1, and PCNA; the cell-cell adhesion molecules of E-cadherin, alpha-catenin, and beta-catenin; and the heat shock proteins of HSP27 and HSP70.

RESULTS

P27KIP1, beta-catenin, and HSP70 were selected for their high hazard ratio in multivariate analysis, and the number of their disordered molecules was used to define the malignancy grade (MG). Five-year survival rates were 83%, 54%, 17%, and 0% for MG1, MG2, MG3, and MG4. The gradation of survival curves was better for MGs than for clinical stages. MGs and clinical stages showed significant correlation; however, 55% of those in higher clinical stages (stage 3 or 4) had lower MG (MG1 or 2) and showed better prognosis than others in their group (stage 3 or 4 and MG3 or 4). The proportions of shorter survival span to cancer death patients (less than 1 year) were 0%, 33%, 75%, and 100% in MG1, 2, 3, and 4, but the clinical stage was not associated with the survival span.

CONCLUSIONS

The grading of malignancy potential is clinically useful, especially for selecting patients who may show good prognosis in the advanced clinical stage and for predicting short survival span. These predictions are not possible with the clinical-stage system, which is based on the anatomic spread of cancer cells.

Epidermal growth factor (EGF) suppresses staurosporine-induced apoptosis by inducing mcl-1 via the mitogen-activated protein kinase pathway

Overexpression of epidermal growth factor receptor (EGFR) and establishment of transforming growth factor alpha (TGF alpha)/EGF autocrine system are frequently detected in tumor cells. In addition to mitogenic ability, we demonstrate in this report that EGF protects a human esophageal carcinoma (CE) cell line, CE81T/VGH, from staurosporine-induced apoptosis. The anti-apoptotic signal of EGF is alleviated by a MEK inhibitor PD98059 or an ERK2 dominant negative mutant but not by a phosphatidylinositol-3'-kinase (PI-3K) inhibitor wortmannin. Furthermore, v-raf blocks apoptosis induced by staurosporine. This evidence implies that the survival signal of EGF is mediated via the Raf-MEK-ERK pathway but not the PI3-K pathway. The survival effect of EGF is coincident with the induction of mcl-1, an antiapoptotic gene in the bcl-2 family. PD98059 also suppresses the induction of Mcl-1 by EGF, implying that EGF may up-regulate Mcl-1 via the MAP kinase pathway. Overexpression of mcl-1 is sufficient to protect against apoptosis, while transfection of a mcl-1 antisense plasmid causes cell death. The expression of mcl-1 antisense plasmid also suppresses the anti-apoptotic effect of EGF. Taken together, these results indicate that EGF may up-regulate Mcl-1 through the MAP kinase pathway to suppress apoptosis.

Role and new perspectives of transforming growth factor-alpha (TGF-alpha) in adenocarcinoma of the gastro-oesophageal junction

The incidence of gastro-oesophageal junction (GEJ) adenocarcinoma is increasing in Western countries and prognosis is poor since metastasis is most often present at diagnosis. We examined samples from 87 resected type II GEJ adenocarcinomas, 30 of these with endoscopic diagnostic biopsy material, to evaluate transforming growth factor alpha (TGF-a) expression and p53 overexpression by immunohistochemistry and in situ hybridization (for TGF-alpha), in relation to biological and clinical behaviour. TGF-alpha messenger RNA (mRNA) and protein were detectable in neoplastic cells in 56% and 64% cases respectively. TGF-alpha mRNA was detected in intra- and peritumoral lymphocytes and those of metastatic lymph nodes. TGF-alpha protein expression was significantly associated with tumour progression (P= 0.025) and lymph node metastasis (P < 0.05). The strong TGF-alpha expression found in neoplastic cells inside blood and lymphatic vessels and in metastatic localizations suggests that TGF-a-positive GEJ adenocarcinomas could have a more aggressive biological phenotype. The expression of TGF-alpha mRNA and protein in both inflammatory and neoplastic cells indicates that TGF-alpha is directly synthesized by both cell compartments. Finally, since TGF-alpha expression was associated with lymph node metastasis, its detection in preoperative perendoscopic biopsies might identify patients with more aggressive tumours who may need additional therapy, including neo-adjuvant treatment.

Prognosis of esophageal squamous cell carcinoma: analysis of clinicopathological and biological factors

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is rather common among the Chinese, but the therapeutic outcome is dismal. Knowledge of the prognostic factors in cancerous patients may influence therapeutic strategy. However, systemic analyses of clinicopathological and biological factors for patients with ESCC are few, and the results are controversial.

METHODS

Between 1985 and 1996, 117 patients undergoing en bloc esophagectomy and gastric substitution were enrolled. None had neoadjuvant treatment. Postoperative adjuvant therapy was provided for patients at and beyond stages IIa. Clinical responses were followed routinely. Flow cytometry was used to measure DNA ploidy and synthesis-phase fraction (SPF) of the resected esophageal tissues from all patients. Immunohistochemistry was also used to examine the expression of proliferating cell nuclear antigen (PCNA), epidermoid growth factor receptor (EGFR), HER-2/neu, and p53 in the pathological sections. Clinical correlation was evaluated by chi2 with Fisher's exact test, and survival by log-rank test.

RESULTS

The overall survival rates were 74% for 1 yr, 48% for 3 yr, and 38% for 5 yr. TNM tumor staging, the number of diseased lymph nodes (N < or = 3 or N > 3), degree of cell differentiation, DNA ploidy, SPF, and lymphovascular invasion were more useful than biological markers, such as PCNA, EGFR, HER-2/neu, and p53, for the prognosis of ESCC. Multivariate analysis revealed significant correlation of tumor staging and number of diseased lymph nodes with patient survival after surgery.

CONCLUSIONS

En bloc esophagectomy may provide a rather satisfactory survival rate for patients with early stage ESCC. However, for patients with distant lymph node metastasis and those with more than three lymph nodes involved, radical surgical resection, even combined with postoperative chemoradiotherapy, cannot improve survival. The prognostic value of biological markers, including PCNA, EGFR, HER-2/neu, and p53, however, is limited.

Prognostic significance of heat shock proteins 27 and 70 in patients with squamous cell carcinoma of the esophagus

BACKGROUND

Heat shock proteins (HSPs) first were defined as proteins induced by heat shock and other environmental and pathophysiologic stresses and are implicated in protein-protein interactions such as folding, translocation, and prevention of inappropriate protein aggregation. Many of their functions suggest that they play important roles in cancer.

METHODS

Immunohistochemical study for HSP 27 and HSP 70 was performed on buffered formalin fixed, paraffin embedded sections of 102 esophageal squamous cell carcinoma specimens using monoclonal anti-HSP 27 antibody and anti-HSP 70 antibody.

RESULTS

Normal squamous cells expressed both HSP 27 and HSP 70 with the exception of the basal layer. In cancerous tissue, expression of HSP 27 was evaluated as positive (+) (39 cases; 38%), reduced (+/-) (53 cases; 52%), or negative (-) (10 cases; 10%) and expression of HSP 70 was evaluated as (+) (14 cases; 14%), (+/-) (57 cases; 56%), or (-) (31 cases; 30%). There was a strong correlation between the expression of HSP 27 and HSP 70 (P < 0.0001). When compared with clinicopathologic features, expression of both HSP 27 and HSP 70 correlated negatively with lymph node metastases (P < 0.05), but not with depth of invasion or histologic grade. The reduction of the HSPs was associated significantly with poor postoperative survival (P < 0.0001). In addition, multivariate analysis revealed that HSP 27 (-) was the strongest prognostic factor among the clinicopathologic features.

CONCLUSIONS

This study suggests that the expression of HSP 27 and HSP 70 frequently is reduced in patients with esophageal squamous cell carcinoma and therefore should be considered an independent prognostic factor of this disease.

Expression of biomarkers (p53, transforming growth factor alpha, epidermal growth factor receptor, c-erbB-2/neu and the proliferative cell nuclear antigen) in oropharyngeal squamous cell carcinomas

Using immunohistochemistry, expression of p53, transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erbB-2/neu and proliferating cell nuclear antigen (PCNA) was examined in 26 fresh frozen tissue specimens of oropharyngeal squamous cell carcinomas (SCCs). p53 gene mutations were examined by polymerase chain reaction (PCR)/DNA sequencing methods in 22 carcinomas. The findings were examined for correlations with patients' clinicopathological parameters. Expressions of p53 and PCNA were also examined in 21 formalin-fixed corresponding tissues. Of the fresh frozen tissue specimens, 77% (20/26) showed expression and 68% (15/22) showed mutations (substitutions) of the p53, with significant clustering of the mutations in exons 5 (8/22; 36%), 7 (4/22; 18%) and 8 (5/22; 23%). No mutations were found in exon 6. There was a discordance between expression of p53 protein and mutations of the gene. Parallel to expression and mutations of the p53 found in most of the specimens, expression of TGF-alpha, EGFR, c-erbB-2/neu and PCNA was found in 88% (22/25), 92% (23/25), 58% (14/24) and 91% (21/23) of the specimens, respectively. For the formalin-fixed tissue specimens, 62% (13/21) and 90% (19/21) expressed p53 and PCNA, respectively. Examining for correlations with patients' clinicopathological parameters, expression of p53, TGF-alpha, EGFR and c-erB-2/neu seemed to negatively correlate with the increase of the tumour grade. The present work suggests that: (1) lack of negative growth regulation due to inactivation of the p53 gene together with activation of other proto-oncogenes are necessary genetic events in the carcinogenesis of oropharyngeal SCCs; (2) in oropharyngeal SCCs, p53 gene mutations were clustered in exons 5 (codons 130-186), 7 (codons 230-248) and 8 (codons 271-282) which perhaps suggests that tobacco carcinogens probably affect the mutational hot spots of the p53 gene at codons 157, 175, 186, 248, 273 and 282; and (3) fresh frozen and formalin-fixed tissue specimens give similar results when an immunohistochemical method is applied. The importance of p53, TGF-alpha, EGFR, c-erbB-2/neu and PCNA as biomarkers in oropharyngeal SCCs deserves particular attention because it might offer further understanding of the development of these carcinomas.

Prognostic significance of heat shock proteins 27 and 70 in patients with squamous cell carcinoma of the esophagus

BACKGROUND

Heat shock proteins (HSPs) first were defined as proteins induced by heat shock and other environmental and pathophysiologic stresses and are implicated in protein-protein interactions such as folding, translocation, and prevention of inappropriate protein aggregation. Many of their functions suggest that they play important roles in cancer.

METHODS

Immunohistochemical study for HSP 27 and HSP 70 was performed on buffered formalin fixed, paraffin embedded sections of 102 esophageal squamous cell carcinoma specimens using monoclonal anti-HSP 27 antibody and anti-HSP 70 antibody.

RESULTS

Normal squamous cells expressed both HSP 27 and HSP 70 with the exception of the basal layer. In cancerous tissue, expression of HSP 27 was evaluated as positive (+) (39 cases; 38%), reduced (+/-) (53 cases; 52%), or negative (-) (10 cases; 10%) and expression of HSP 70 was evaluated as (+) (14 cases; 14%), (+/-) (57 cases; 56%), or (-) (31 cases; 30%). There was a strong correlation between the expression of HSP 27 and HSP 70 (P < 0.0001). When compared with clinicopathologic features, expression of both HSP 27 and HSP 70 correlated negatively with lymph node metastases (P < 0.05), but not with depth of invasion or histologic grade. The reduction of the HSPs was associated significantly with poor postoperative survival (P < 0.0001). In addition, multivariate analysis revealed that HSP 27 (-) was the strongest prognostic factor among the clinicopathologic features.

CONCLUSIONS

This study suggests that the expression of HSP 27 and HSP 70 frequently is reduced in patients with esophageal squamous cell carcinoma and therefore should be considered an independent prognostic factor of this disease.

Levels of TGF-alpha and EGFR protein in head and neck squamous cell carcinoma and patient survival

BACKGROUND

The most accurate predictor of disease recurrence in patients treated for head and neck squamous cell carcinoma is, at present, the extent of regional lymph node metastasis. Since elevated levels of epidermal growth factor receptor (EGFR) and of its ligand, transforming growth factor-alpha (TGF-alpha), have been detected in primary tumors of patients with head and neck squamous cell carcinoma, we determined whether tumor levels of these proteins were of prognostic importance.

METHODS

Monoclonal antibodies specific for EGFR and TGF-alpha were used for immunohistochemical detection of each protein in tissue sections of primary tumors from 91 patients who were treated by surgical resection. Levels of immunoreactive EGFR and TGF-alpha were quantified by use of a computerized image analysis system and were normalized to appropriate standards. The logrank test and proportional hazards regression analysis were used to calculate the probability that EGFR and TGF-alpha levels were associated with disease-free survival (i.e., no recurrence of cancer) and cause-specific survival (i.e., patients do not die of their disease). All P values were two-sided.

RESULTS

When tumor levels of EGFR or TGF-alpha were analyzed as continuous variables, disease-free survival and cause-specific survival were reduced among patients with higher levels of EGFR (both P = .0001) or TGF-alpha (both P = .0001). In a multivariate analysis, tumor site, tumor level of EGFR, and tumor level of TGF-alpha were statistically significant predictors of disease-free survival; in a similar analysis, regional lymph node stage and tumor levels of EGFR and of TGF-alpha were significant predictors of cause-specific survival.

CONCLUSION

Quantitation of EGFR and TGF-alpha protein levels in primary head and neck squamous cell carcinomas may be useful in identifying subgroups of patients at high risk of tumor recurrence and in guiding therapy.