Clinical Outcomes of Second-Line Chemotherapy in Patients with Previously Treated Advanced Thymic Carcinoma: A Retrospective Analysis of 191 Patients from the NEJ023 Study.

BACKGROUND: Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma. MATERIAL AND METHODS: We performed a multi-institutional, retrospective study named NEJ023 for patients with advanced thymic carcinoma. Patients without indications for curative treatment were treated with chemotherapy from 1995 to 2014 at 40 institutions in the North East Japan Study Group. Demographic and clinicopathologic characteristics, data on treatment methods, and outcomes of second-line chemotherapy were obtained from medical records. RESULTS: In total, 191 patients were enrolled in this study. Second-line chemotherapy included platinum-based doublets in 57.6% of patients, other multidrug chemotherapy (e.g., cisplatin, doxorubicin, vincristine, and cyclophosphamide) in 13.6%, and monotherapy in 28.8%. The median follow-up time was 50.5 months, and the median overall survival (OS) from the start of second-line chemotherapy was 22.4 (95% confidence interval, 17.5-26.7) months. The average response rate (RR) was 20.0% overall; it was 21.6% for patients treated with platinum-based doublet chemotherapy, 13.6% for those treated with other multidrug chemotherapy, and 19.6% for those treated with single agent chemotherapy. There was no significant difference in OS between platinum-based doublet chemotherapy, other multidrug chemotherapy, and monotherapy (the median OS was 22.4, 25.7, and 21.4 months, respectively). CONCLUSION: The median OS was 22.4 months in patients with advanced thymic carcinoma treated with second-line chemotherapy. There were no significant differences in RR and OS between monotherapy and multidrug chemotherapy in this study. IMPLICATIONS FOR PRACTICE: Owing to the rarity of this tumor, there is limited information about second-line chemotherapy for patients with previously treated advanced thymic carcinoma. This is the largest data for those patients treated with second-line chemotherapy. This study suggests there is no significant difference in efficacy between monotherapy and multidrug chemotherapy for previously treated advanced thymic carcinoma. This result can support the adequacy to select monotherapy as treatment of those patients.

Validation of prognostic impact of number of extrathoracic metastases according to the eighth TNM classification: a single-institution retrospective study in Japan.

BACKGROUND: In the eighth edition of the TNM classification of lung cancer, the M1b and M1c descriptors are newly defined by the number of extrathoracic metastases. To verify the prognostic value of these descriptors in Japan, we reclassified our cases and re-evaluated prognosis in M1b and M1c patients. METHODS: All non-small cell lung cancer (NSCLC) patients with extrathoracic metastases who visited Saitama Medical Center from 2010 to 2016 were evaluated, divided according to the eighth edition of the TNM classification criteria into two groups (M1b, patients with single extrathoracic metastasis, and M1c, patients with multiple extrathoracic metastases), and followed up until December 31, 2017. Survival time analysis was performed using the Kaplan-Meier method, and between-group differences in overall survival time (OS) were evaluated by the log-rank test. RESULTS: A total of 231 NSCLC patients were divided into 57 patients with M1b and 174 with M1c. Median OS was 15.2 months (95% confidence interval [CI]: 9.3-19.9) and 7.3 months (95% CI 5.7-10.7) for M1b and M1c, respectively, with no significant between-group difference (P = 0.239). However, after excluding patients with epidermal growth factor receptor (EGFR) mutation or echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (EML4-ALK) fusion gene, median OS was 12.9 months (95% CI 7.2-19.9) for M1b and 5.4 months (95% CI 3.8-6.3) for M1c, respectively, showing a significant difference (P = 0.029). CONCLUSIONS: The effect of therapy directed toward EGFR mutation or EML4-ALK fusion gene might obscure the significant prognostic difference between M1b and M1c.

Anti-neutrophil cytoplasmic antibody-negative granulomatosis with polyangiitis manifesting through pulmonary nodules and a genital lesion.

A 72-year-old female presented with bilateral pulmonary nodules before undergoing surgery for hysteroptosis. Transbronchial biopsy did not lead to a definitive diagnosis. The right mass in the upper lobe was resected through video-assisted thoracic surgery. Pathological findings showed granulomatosis with polyangiitis. However, the patient was negative for serum proteinase 3-anti-neutrophil cytoplasmic antibody. Although the nodule in the left lower lobe progressed, the serum inflammatory reaction yielded negative results. Resection of the nodule in the left lower lobe revealed identical pathological findings with those of the right pulmonary mass. Following total hysterectomy for hysteroptosis, the pathological findings indicated granulomatosis with polyangiitis.

Impact of Locoregional Therapies for Brain Lesions on Survival in Patients With Non-small Cell Lung Cancer With Multiple Extrathoracic Metastases.

BACKGROUND/AIM: The treatment of brain metastases in patients with non-small cell lung cancer (NSCLC) typically involves surgery, irradiation, and chemotherapy (single or combination therapy). However, the impact of these therapies on the survival of patients with NSCLC with multiple extrathoracic metastases has not yet been determined. Therefore, in the present study, we examined the prognostic effect of multimodal treatment for brain metastases in patients with NSCLC with multiple extrathoracic metastases in the absence of driver mutations. PATIENTS AND METHODS: Patients with NSCLC with multiple extrathoracic metastases (including at least one brain metastasis), who visited Saitama Medical Center, Saitama Medical University from January 1, 2010 to December 31, 2016, were enrolled in this study; follow-up was conducted until December 31, 2021. RESULTS: A total of 56 patients were enrolled, including 12 and 44 patients with single and multiple brain metastases, respectively. The median overall survival (OS) for all patients was 4.9 months, and did not differ significantly between patients with single and multiple brain metastases (3.0 vs. 4.9 months, respectively). The selection of locoregional treatment for brain metastases did not depend on Karnofsky performance status (p=0.0862). Among patients with multiple brain metastases, the OS for those who underwent craniotomy followed by whole brain radiation therapy (WBRT), those who received only WBRT, and those treated without locoregional therapy was 47.7, 3.9, and 15.9 months, respectively (p=0.00382). CONCLUSION: Surgical resection followed by radiation therapy is an effective treatment option for brain metastases in patients with multiple metastases. However, WBRT alone did not improve prognosis.

Nintedanib induces gene expression changes in the lung of induced-rheumatoid arthritis-associated interstitial lung disease mice.

Nintedanib is a multi-tyrosine kinase inhibitor widely used to treat progressive fibrosing interstitial lung diseases because it slows the reduction in forced vital capacity. However, the prognosis for patients treated with nintedanib remains poor. To improve nintedanib treatment, we examined the effects of nintedanib on gene expression in the lungs of induced-rheumatoid arthritis-associated interstitial lung disease model mice, which develop rheumatoid arthritis and subsequent pulmonary fibrosis. Using next-generation sequencing, we identified 27 upregulated and 130 downregulated genes in the lungs of these mice after treatment with nintedanib. The differentially expressed genes included mucin 5B and heat shock protein 70 family genes, which are related to interstitial lung diseases, as well as genes associated with extracellular components, particularly the myocardial architecture, suggesting unanticipated effects of nintedanib. Of the genes upregulated in the nintedanib-treated lung, expression of regulatory factor X2, which is suspected to be involved in cilia movement, and bone morphogenetic protein receptor type 2, which is involved in the pathology of pulmonary hypertension, was detected by immunohistochemistry and RNA in situ hybridization in peripheral airway epithelium and alveolar cells. Thus, the present findings indicate a set of genes whose expression alteration potentially underlies the effects of nintedanib on pulmonary fibrosis. It is expected that these findings will contribute to the development of improved nintedanib strategies for the treatment of progressive fibrosing interstitial lung diseases.

Initial rapidity of tumor growth as a prognostic factor for the therapeutic effect of immune-checkpoint inhibitors in patients with non-small cell lung cancer: evaluation for linear and non-linear correlation.

BACKGROUND: Immune-checkpoint inhibitors (ICIs) have been increasingly used for non-small cell lung cancer (NSCLC) treatment in recent years. Although insufficient, the rate of programmed death-ligand 1 expression has been adopted as a predictor of ICI efficacy. We evaluated tumor growth rate as a clinically easy-to-use predictor of the therapeutic effect of ICIs. METHODS: This study is a single-institution retrospective study in Japan. NSCLC patients treated with nivolumab, pembrolizumab, or atezolizumab at Saitama Medical Center from January 1, 2016 to December 31, 2018 were enrolled, and followed until December 31, 2020. We defined and calculated the initial rapidity of tumor progression (IRP) as: the increase in the sum of the diameters of intrathoracic tumors and lymph nodes on two series of chest computed tomography (CT) scans (one obtained at an initial checkup and the other obtained immediately before the first treatment) divided by the number of days between these CT scans. Two coefficients were calculated: the maximal information coefficient (MIC) between IRP and time to treatment failure (TTF) using the Python package with minepy library, and the Spearman's rank correlation coefficient. RESULTS: A total of 55 patients (median age, 70 years; 47 men) were enrolled. The median TTF with ICIs was 126 days, and four patients continued to receive ICI treatment at the end of the follow-up. The MIC between IRP and TTF was 0.302 with weak correlation, and the Spearman's rank correlation coefficient was -0.347 (P=0.00938). CONCLUSIONS: The initial tumor growth rate had a negative linear correlation with the therapeutic effect of ICIs.

A novel isoform of Homeodomain-interacting protein kinase-2 promotes YAP/TEAD transcriptional activity in NSCLC cells.

Homeodomain-interacting protein kinase-2 (HIPK2) can either promote or inhibit transcription depending on cellular context. In this study, we show that a new HIPK2 isoform increases TEAD reporter activity in NSCLC cells. We detected HIPK2 copy number gain in 5/6 (83.3%) NSCLC cell lines. In NSCLC patients with high HIPK2 mRNA expression in the Human Protein Atlas, the five-year survival rate is significantly lower than in patients with low expression (38% vs 47%; p = 0.047). We also found that 70/78 (89.7%) of NSCLC tissues have moderate to strong expression of the N-terminal HIPK2 protein. We detected and cloned a novel HIPK2 isoform 3 and found that its forced overexpression promotes TEAD reporter activity in NSCLC cells. Expressing HIPK2 isoform 3_K228A kinase-dead plasmid failed to increase TEAD reporter activity in NSCLC cells. Next, we showed that two siRNAs targeting HIPK2 decreased HIPK2 isoform 3 and YAP protein levels in NSCLC cells. Degradation of the YAP protein was accelerated after HIPK2 knockdown in NSCLC cells. Inhibition of HIPK2 isoform 3 decreased the mRNA expression of YAP downstream gene CTGF. The specific HIPK2 kinase inhibitor TBID decreased TEAD reporter activity, reduced cancer side populations, and inhibited tumorsphere formation of NSCLC cells. In summary, this study indicates that HIPK2 isoform 3, the main HIPK2 isoform expressed in NSCLC, promotes YAP/TEAD transcriptional activity in NSCLC cells. Our results suggest that HIPK2 isoform 3 may be a potential therapeutic target for NSCLC.

Functional inhibition of heat shock protein 70 by VER-155008 suppresses pleural mesothelioma cell proliferation via an autophagy mechanism.

BACKGROUND: Pleural mesothelioma, a devastating asbestos-associated malignancy, urgently requires a novel effective therapy. Heat shock protein 70 (HSP70), which is synthesized in the cell response to protein damage, is expected to be a new target for antitumor treatment. In addition to its well-known protein refolding function, HSP70 regulates cell proliferation through different pathways, including PI3K/AKT/mTOR, and autophagy in malignant cells. In this study, we attempted to clarify the effects of VER-155008, an HSP70 inhibitor, on pleural mesothelioma. METHODS: Human pleural mesothelioma cell lines 211H, H2452 and H28 were cultured with VER-155008, and protein expression, cell proliferation, colony formation, cell cycle, synergistic effect with cisplatin, and autophagy induction were analyzed. RESULTS: In mesothelioma cell lines, VER-155008 (5.0 µM or more) inhibited cell growth and colony formation, accompanied by G1 cell cycle arrest. According to western blot analysis, VER-155008 reduced p-AKT expression. However, VER-155008 failed to show a synergistic effect with cisplatin on cell growth. Mesothelioma cells transfected with the novel plasmid pMRX-IP-GFP-LC3-RFP-LC3ΔG, which was developed for the quantitative and statistical estimation of macroautophagy, showed enhanced macroautophagy upon treatment with VER-155008 and gefitinib which is an EGFR-tyrosine kinase inhibitor. In addition, fetal bovine serum deprivation induced macroautophagy was further enhanced by VER-155008. CONCLUSIONS: On the basis of these results, functional HSP70 inhibition by VER-155008 suppressed cell growth in pleural mesothelioma cells, accompanied by enhanced macroautophagy. HSP70 inhibition is thus expected to become a new strategy for treating mesothelioma. KEY POINTS: Significant findings of the study In pleural mesothelioma cells, inhibition of HSP70 function by VER-155008 suppressed cell proliferation accompanied by induction of autophagy which was synergistically enhanced under the starvation condition, whereas gefitinib, an EGFR-TKI, did not show the same synergistic effect in autophagy. What this study adds The inhibition of HSP70 induced autophagy and suppressed cell proliferation in mesothelioma cells.

Frequency of and variables associated with the EGFR mutation and its subtypes.

Mutation in the epidermal growth factor receptor (EGFR) is frequently seen in non-small cell lung cancers (NSCLCs), especially in Asian females with adenocarcinoma. The frequency of mutation and the factors associated requires to be elucidated by analyzing a large number of consecutive clinical samples. We summarized the result of the EGFR mutation analysis for 1,176 patients performed at the time of diagnosis or relapse. The PNA-LNA PCR clamp, a highly sensitive detection method for the EGFR mutation, was employed. For fresh cases a portion of samples isolated to establish the diagnosis of lung cancer was used. For cases with a relapsed disease archival tissue were tested. The variables associated with the EGFR mutation after removing the confound factors were investigated by the logistic analysis using the samples collected in our university (n = 308) where detailed information on patients were available. The frequency of the EGFR mutation and its subtypes were investigated using all samples (n = 1,176). The EGFR mutation was significantly associated with adenocarcinoma (p = 0.006) and light-smoking (p < 0.0001), but not gender. The deletions in exon 19 were more frequently associated with male gender while exon 21 deletions were with female gender (p = 0.0011). The overall frequency of the EGFR mutation was 31%. Our result suggests that the female predominance in the EGFR mutation rate is a reflection of a higher frequency of adenocarcinoma in females. The gender difference in the mutation subtypes may provide a clue for the mechanism of the occurrence of the EGFR mutation.

An antagonist of dishevelled protein-protein interaction suppresses beta-catenin-dependent tumor cell growth.

Recent progress in the development of inhibitors of protein-protein interactions has opened the door for developing drugs that act by novel and selective mechanisms. Building on that work, we designed a small-molecule inhibitor of the Wnt signaling pathway, which is aberrantly activated across a wide range of human tumors. The compound, named FJ9, disrupts the interaction between the Frizzed-7 Wnt receptor and the PDZ domain of Dishevelled, down-regulating canonical Wnt signaling and suppressing tumor cell growth. The antitumorigenic effects of FJ9 were pronounced, including induction of apoptosis in human cancer cell lines and tumor growth inhibition in a mouse xenograft model. FJ9 is thus among the first non-peptide inhibitors to show therapeutic efficacy through disruption of PDZ protein-protein interactions.

Vascular Ehlers-Danlos Syndrome with a Novel Missense Mutation in COL3A1: A Man in His 50s with Aortic Dissection after Interventional Treatment for Hemothorax as the First Manifestation.

Type III collagen is the major protein in the walls of blood vessels and hollow organs; it is decreased in patients with vascular Ehlers-Danlos syndrome (EDS). A 52-year-old man was admitted for severe back pain, and right hemothorax was suspected by chest computed tomography. Immediately after embolization for bleeding bronchial artery, aortic dissection occurred and was treated conservatively in the intensive-care unit. Vascular EDS with a mutation of COL3A1 cDNA (c.3175G>A) was diagnosed. When vascular EDS is suspected, the patient should be treated prophylactically, and a genetic examination should be performed to confirm the diagnosis.

Inhibitory effect of budesonide alone and in combination with formoterol on IL-5 and RANTES production from mononuclear cells.

BACKGROUND: The use of a budesonide (BUD)/formoterol (FOR) combination (Symbicort) for both maintenance and reliever therapy reduces the exacerbation of asthma better than the traditional fixed-dose regimens. In the early stage of exacerbation, the combination therapy could intervene with the development of subsequent airway inflammation. The objective of the study was to evaluate whether in the early stage of cell activation the use of BUD/FOR combination would modify the adhesion of eosinophils or production of cytokines from mononuclear cells. METHODS: Human peripheral blood eosinophils, pretreated with BUD (0.1 microM), FOR (0.1 microM) or BUD/FOR combination for 30 min at 37 degrees C, were stimulated with IL-5, leukotriene D4 or phorbol myristate acetate, and eosinophil adhesion was evaluated using an eosinophil peroxidase assay. BUD (0.1 microM), FOR (0.1 microM) or BUD/FOR combination was added to the peripheral blood mononuclear cells stimulated with ionomycin plus phorbol myristate acetate. Concentrations of IL-5 and RANTES in the cell supernatant were measured using ELISA. RESULTS: BUD, FOR or BUD/FOR combination did not modify the eosinophil adhesion induced by any stimulators. In contrast, BUD or BUD/FOR combination significantly reduced the productions of IL-5 and RANTES in peripheral blood mononuclear cells (BUD: p < 0.0001, p = 0.027 vs. control; BUD/FOR: p < 0.0001, p = 0.031 vs. control) when the drugs were added 15 min, but not 4 h, following cell stimulation. CONCLUSION: In the early stage of exacerbation of asthma, inhaled BUD may suppress the progression of the allergic inflammatory cascade by inhibiting the mononuclear cells. These results also underline the importance of using BUD in rescue inhaler.

Synergistic effect of targeting dishevelled-3 and the epidermal growth factor receptor-tyrosine kinase inhibitor on mesothelioma cells in vitro.

It was previously revealed that Wnt signaling is activated in mesothelioma cells. Although epidermal growth factor receptor (EGFR) is expressed in mesothelioma cells, EGFR-tyrosine kinase inhibitors (TKIs) are not effective for mesothelioma treatment. However, in non-small cell lung cancer, the blocking of Wnt signaling has been identified to enhance the anticancer effect of EGFR-TKIs. To confirm the anticancer effect of blocking Wnt signaling in combination with EGFR-TKI treatment in mesothelioma, the present study evaluated the effect of simultaneous suppression of human dishevelled-3 (Dvl-3) expression with Dvl-3 small interfering RNA (siRNA) and of EGFR inhibition with gefitinib on mesothelioma cell viability. Mesothelioma cell lines with and without ß-catenin gene expression were transfected with Dvl-3 siRNA and were cultured with gefitinib, and cell viability, colony formation and cell cycle analyses were performed. Dvl-3 siRNA downregulated the expression of Dvl-3 in mesothelioma cells. The combination of Dvl-3 siRNA with gefitinib acted synergistically to induce concomitant suppression of cell viability and colony formation, suggesting that inhibition of Wnt signaling by downregulating Dvl-3 with siRNA and inhibiting EGFR with gefitinib leads to significant antitumor effects.

Targeting the Wnt signaling pathway with dishevelled and cisplatin synergistically suppresses mesothelioma cell growth.

BACKGROUND: We have previously found that Wnt signaling is activated in mesothelioma cells. To clarify the effect of blocking Wnt signaling in mesothelioma, the expression of dishevelled (Dvl), an intermediator of Wnt signaling, was down-regulated by a reformed type of small interfering RNA (siRNA), stealth RNAi, which can reduce the cytotoxic interferon response unlike conventional siRNA. MATERIALS AND METHODS: Mesothelioma cell lines were transfected with stealth RNAi of Dvl, and cell growth and colony formation were examined. The synergistic effect on cell growth of Dvl stealth RNAi and cisplatin in combination was evaluated. RESULTS: Dvl stealth RNAi down-regulated the expression of Dvl-3 in mesothelioma cells and induced cell cycle aberration which caused suppression of cell growth. Colony formation was also suppressed. Dvl stealth RNAi and cisplatin in combination suppressed cell growth synergistically. CONCLUSION: Our data suggest that inhibition of Wnt signaling leads to significant antitumor effects.

Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon: Results of a preliminary study.

Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected pulmonary function. Xenon images obtained with xenon-enhanced CT using a single-breath-hold technique can qualitatively depict pulmonary ventilation. A larger study comprising only COPD patients should be conducted, as xenon-enhanced CT is expected to be a promising technique for the management of COPD.

Prognostic value of expression of vascular endothelial growth factor and its flt-1 and KDR receptors in stage I non-small-cell lung cancer.

BACKGROUND: Angiogenesis plays an important role in tumorigenesis and has attracted interest as a potential target in cancer treatment. PATIENTS AND METHODS: We examined the prognostic value of the expression of vascular endothelial growth factor (VEGF) and of the VEGF receptors (VEGFRs) fms-like tyrosine kinase receptor-1 (flt-1) and kinase insert domain-containing receptor (KDR) in non-small-cell lung cancer (NSCLC). Sixty patients with surgical stage I NSCLC who had not undergone induction therapy or adjuvant therapy were selected from among 170 patients with NSCLC who had undergone surgery from January to December 1995. Specimens obtained at surgical resection were subjected to immunohistological staining, and the relationship between postoperative outcome and the expression of VEGF and its receptors was investigated. All patients included in the analysis had been followed up for 5 years or longer or until death. RESULTS: Patients with tumors expressing VEGF or KDR tended to have poorer outcomes, and VEGF expression and KDR expression were positively correlated. In contrast, flt-1 expression was not correlated with VEGF expression or outcome. Outcomes were poor in patients with tumors positive for both VEGF and VEGFRs. Multivariate analysis identified expression of both flt-1 and KDR and VEGF and KDR as possible independent prognostic factors. CONCLUSIONS: Our results suggest that expression of VEGF and VEGFR are associated with a poor prognosis via autocrine and paracrine growth stimulation of cancer cells. Moreover, tumors expressing both flt-1 and KDR may have greater malignant potential and are associated with a poor prognosis.

Inhibition of Wnt-1 signaling induces apoptosis in beta-catenin-deficient mesothelioma cells.

It is known that Wnt-1 signaling inhibits apoptosis by activating beta-catenin/tcf-mediated transcription. Here, we show that blocking Wnt-1 signaling in beta-catenin-deficient mesothelioma cell lines H28 and MS-1 induces apoptotic cell death. Both Wnt-1 small interfering RNA (siRNA) and Dishevelled siRNA induced significant apoptosis in these cell lines. A small molecule inhibitor of c-Jun NH(2)-terminal kinase inhibited the apoptotic cell killing induced by either Wnt-1 siRNA or Dishevelled siRNA in these cells. Our data suggest that beta-catenin-independent noncanonical pathway(s), i.e., Wnt/JNK pathway, may play a role in the apoptotic inhibition caused by Wnt-1 signaling.

Wnt pathway activation in mesothelioma: evidence of Dishevelled overexpression and transcriptional activity of beta-catenin.

Malignant pleural mesothelioma is a relatively uncommon and yet incurable tumor. The pathogenesis of mesothelioma remains poorly understood. This study evaluated the role of Wnt signaling in mesothelioma. Western blot analysis was conducted to confirm the expression of Dishevelled (Dvl) and cytosolic beta-catenin in matched autologous tissue samples (tumor and normal pleura), malignant pleural effusions, and in established mesothelioma cell lines LRK1A, REN and H513. Thirteen of 15 mesotheliomas examined showed consistent overexpression of Dvl and increased cytosolic beta-catenin levels as compared with controls. To evaluate T-cell factor (Tcf)-dependent transcriptional activity of beta-catenin, luciferase assays were conducted. Fresh mesothelioma cells (effusion derived), as well as LRK1A, REN, and H513 cell lines showed a significant fold increase (1.5-2.4-fold, P < 0.01) in Tcf-dependent transcriptional activity of beta-catenin. To evaluate the biological significance of Dvl function in mesothelioma, a PDZ domain deletion mutant (DeltaPDZ-Dvl) was created and stably transfected into LRK1A, REN, and H513. The effect of DeltaPDZ-Dvl on mesothelioma growth was assayed in vitro (colony formation assay in soft agar) and in vivo (s.c. implantation in athymic mice NCRNU-M). In mesothelioma cells tested, DeltaPDZ-Dvl-mediated inhibition of Dvl decreased cytosolic beta-catenin levels, diminished Tcf-mediated transcription, and suppressed tumorigenesis of LRK1A and REN in vitro and in vivo. DeltaPDZ-Dvl also down-regulated expression of c-myc in REN and COX-2 in H513. Our data suggest that in malignant pleural mesothelioma, Wnt signaling is activated through Dvl overexpression and downstream signaling through beta-catenin. Inhibition of this signaling leads to significant antitumor effects. These results demonstrate Dvl overexpression in human cancer and, specifically, that Wnt signaling plays a role in mesothelioma pathogenesis. These data offer possible new avenues for therapeutic intervention.

An anti-Wnt-2 monoclonal antibody induces apoptosis in malignant melanoma cells and inhibits tumor growth.

Activation of the Wnt/beta-catenin signaling pathway has been associated with human cancers. To test whether Wnt-2 signal is a survival factor in human melanoma cells and thus represents a potential therapeutic target, we investigated the effects of inhibition of Wnt-2 signaling in human melanoma cell lines. We have developed a novel monoclonal antibody against the NH(2) terminus of the human Wnt-2 ligand that induces apoptosis in human melanoma cells overexpressing Wnt-2. Whereas incubation of this antibody with normal cells lacking Wnt-2 expression does not induce apoptosis, Wnt-2 signaling blockade by the ligand-binding antibody is confirmed by down-regulation of Dishevelled and beta-catenin. Wnt-2 small interfering RNA treatment in these cells yielded similar apoptotic effects and downstream changes. Down-regulation of an inhibitor of apoptosis family protein, survivin, was observed in both the Wnt-2 antibody-treated and small interfering RNA-treated melanoma cell lines, suggesting that the antibody induces apoptosis by inactivating survivin. In an in vivo study, this monoclonal anti-Wnt-2 antibody suppresses tumor growth in a xenograft model. These findings suggest that the anti-Wnt-2 monoclonal antibody may be useful for the treatment of patients with malignant melanoma.

Activation of the Wnt pathway in non small cell lung cancer: evidence of dishevelled overexpression.

Non small cell lung cancer (NSCLC) is the leading cause of cancer deaths in the United States and worldwide. Unfortunately, standard therapies remain inadequate. An increased understanding of the molecular biology of lung cancer biology is required to develop more effective new therapies. In this report, we show that the Wnt pathway is activated through Dishevelled (Dvl) overexpression in NSCLC. Analysis of freshly resected tumors and lung cancer cell lines demonstrate that Dvl-3, a critical mediator of Wnt signaling, is overexpressed. Specifically, Dvl-3 was overexpressed significantly in 75% of fresh NSCLC microdissected samples compared to control paired matched normal lung samples. To evaluate the biological significance of Wnt signaling and, in particular, Dvl function in lung cancer, we transfected siRNA (designed to inhibit selectively human Dvl-1, -2, and -3), to the NSCLC cell line H1703, which is known to have beta-catenin-mediated Tcf-dependent transcriptional activity. Here, we demonstrate that Dvl-specific siRNA treatment in H1703 decreases significantly Dvl and beta-catenin expression, resulting in reduction of Tcf-dependent transcriptional activity, and, importantly, growth inhibition. Taken together, these data support the novel hypothesis that Dvl overexpression is critical to Wnt signaling activation and cell growth in NSCLC.