The Combination of Trametinib, a MEK Inhibitor, and Temsirolimus, an mTOR Inhibitor, Radiosensitizes Lung Cancer Cells.

BACKGROUND/AIM: We evaluated the radiosensitizing effect of the combination treatment of trametinib, a MEK inhibitor, and temsirolimus, an mTOR inhibitor, on non-small-cell lung carcinoma (NSCLC) cells. MATERIALS AND METHODS: The effects of combining trametinib and temsirolimus with radiation in NSCLC cell lines were evaluated using clonogenic survival and apoptosis assays. DNA double-strand breaks and cell cycle distribution were analyzed using flow cytometry. Tumor volume was measured to determine the radiosensitivity in lung cancer xenograft models. RESULTS: Exposure of lung cancer cells to a combination of trametinib and temsirolimus reduced clonogenic survival and promoted radiation-induced apoptosis. Combined inhibition of MEK and mTOR induced prolonged expression of γH2AX after irradiation and resulted in prolonged G2/M cell cycle arrest after irradiation in A549 cells. In vivo studies revealed that co-administration of the drugs sensitizes lung cancer xenografts to radiotherapy. CONCLUSION: The combination of trametinib and temsirolimus can enhance lung cancer radiosensitivity in vitro and in vivo.

Anti-tumor effect of CDK inhibitors on CDKN2A-defective squamous cell lung cancer cells.

BACKGROUND: Squamous cell lung cancer (SqCLC) is a distinct histologic subtype of non-small cell lung cancer (NSCLC). Although the discovery of driver mutations and their targeted drugs has remarkably improved the treatment outcomes for lung adenocarcinoma, currently no such molecular target is clinically available for SqCLC. The CDKN2A locus at 9p21 encodes two alternatively spliced proteins, p16INK4a (p16) and p14ARF (p14), which function as cell cycle inhibitors. The Cancer Genome Atlas (TCGA) project revealed that CDKN2A is inactivated in 72% of SqCLC cases. In addition, it was found that CDKN2A mutations are significantly more common in SqCLC than in adenocarcinoma. Down-regulation of p16 and p14 by CDKN2A gene inactivation leads to activation of cyclin-dependent kinases (CDKs), thereby permitting constitutive phosphorylation of Rb and subsequent cell cycle progression. Here, we hypothesized that CDK inhibition may serve as an attractive strategy for the treatment of CDKN2A-defective SqCLC. METHODS: We investigated whether the CDK inhibitors flavopiridol and dinaciclib may exhibit antitumor activity in CDKN2A-defective SqCLC cells compared to control cells. The cytotoxic effect of the CDK inhibitors was evaluated using cell viability assays, and the induction of apoptosis was assessed using TUNEL assays and Western blot analyses. Finally, anti-tumor effects of the CDK inhibitors on xenografted cells were investigated in vivo. RESULTS: We found that flavopiridol and dinaciclib induced cytotoxicity by enhancing apoptosis in CDKN2A-defective SqCLC cells, and that epithelial to mesenchymal transition (EMT) decreased and autophagy increased during this process. In addition, we found that autophagy had a cytoprotective role. CONCLUSION: Our data suggest a potential role of CDK inhibitors in managing CDKN2A-defective SqCLC.

Cytologic features of primary monophasic synovial sarcoma of the thyroid gland.

Synovial sarcoma (SS) is a rare soft tissue tumor, commonly arising in para-articular areas of extremities, but can also present in the head and neck area. However, primary SS of the thyroid gland is an extremely rare tumor which has been reported only five times in previous English literatures. This report presents fine needle aspiration (FNA) cytology of primary monophasic SS of the thyroid gland. A 47-year- old woman incidentally detected thyroid nodule in the isthmus of right thyroid gland on an ultrasonography by regular health check-up. Because the possibility of malignancy could not be ruled out, FNA and surgical resection were performed. The cytological, histopathological, immunohistochemical, and molecular genetic study of SYT-SSX transcript were discussed. For the past 3 years of follow-up after surgery, no recurrence or metastasis has been identified.

Altered expression of cellular proliferation, apoptosis and the cell cycle-related genes in lung cancer cells with acquired resistance to EGFR tyrosine kinase inhibitors.

Non-small cell lung cancers harboring somatic gain-of-function mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase domain respond well to treatment with EGFR tyrosine kinase inhibitors (TKIs) including gefitinib and erlotinib. However, all patients who experience a marked improvement with these drugs eventually develop disease progression due to the acquisition of drug resistance. Approximately half of the cases with acquired resistance to EGFR TKIs can be accounted for by a second-site mutation in exon 20 of the EGFR kinase domain (T790M). However, the changes of gene expression involved in EGFR TKI resistance due to the T790M mutation remain poorly defined. The present study established lung cancer cell lines that were resistant to gefitinib or erlotinib, and these cell lines were verified to contain the EGFR T790M mutation. The differential expression of genes associated with acquired resistance was verified in the present study by mRNA microarray analysis. Among the genes whose expression was significantly altered, genes whose expression was altered in gefitinib- and erlotinib-resistant cells were focused on. Notably, a total of 1,617 genes were identified as being differentially expressed in gefitinib- and erlotinib-resistant cells. Indeed, Gene ontology analysis revealed altered expression of genes involved in the regulation of cellular proliferation, apoptosis, and the cell cycle in EGFR TKI-resistant cells. The present results demonstrate distinctive gene expression patterns of EGFR TKI-resistant lung cancer cells with the EGFR T790M mutation. The present study can provide key insights into gene expression profiles involved in conferring resistance to EGFR TKI therapy in lung cancer cells.

Fhit, a tumor suppressor protein, induces autophagy via 14-3-3τ in non-small cell lung cancer cells.

Inactivation of the fragile histidine triad (Fhit) gene has been reported in the majority of human cancers, particularly in lung cancer. The role of Fhit as a tumor suppressor gene has been well documented, and restoration of Fhit expression suppresses tumorigenicity in tumor cell lines and in mouse models by inducing apoptosis and inhibiting proliferation of tumor cells. Autophagy is a catabolic pathway, whereby cytoplasmic proteins and organelles are sequestered in vacuoles and delivered to lysosomes for degradation and recycling. Although autophagy is necessary for cell survival under stress conditions, recent studies have shown that autophagy can also promote cell death. Due to the fact that both autophagy induction and Fhit expression are commonly associated with nutrient starvation, we hypothesized that Fhit expression may be related to autophagy induction. In the present study, we assessed whether Fhit overexpression by gene transfer induces autophagy in Fhit-deficient non-small cell lung cancer (NSCLC) cells. The results of our study indicate that Fhit protein induces autophagy in NSCLC cells, and that this autophagy prevents apoptotic cell death in vivo and in vitro in a 14-3-3τ protein-dependent manner. To the best of our knowledge, this is the first report to describe Fhit-induced autophagy. Suppressing autophagy might be a promising therapeutic option to enhance the efficacy of Fhit gene therapy in NSCLC.

The combination of irreversible EGFR TKIs and SAHA induces apoptosis and autophagy-mediated cell death to overcome acquired resistance in EGFR T790M-mutated lung cancer.

To overcome T790M-mediated acquired resistance of lung cancer cells to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), second generation TKIs such as BIBW2992 (afatinib) and third generation TKIs including WZ4002 have been developed. However, clinical data on their efficacy in treating T790M mutant tumors are lacking. Histone deacetylase (HDAC) inhibitors have been reported to arrest cell growth and to lead to differentiation and apoptosis of various cancer cells, both in vitro and in vivo. In the present study, we assessed whether the combination of suberoylanilide hydroxamic acid (SAHA, vorinostat), a potent HDAC inhibitor, and BIBW2992 or WZ4002 could overcome EGFR TKI resistance associated with T790M mutation in lung cancer cells. While treatment with BIBW2992 or WZ4002 alone slightly reduced the viability of PC-9G and H1975 cells, which possess T790M mutation, combining them with SAHA resulted in significantly decreased cell viability through the activation of the apoptotic pathway. This combination also enhanced autophagy occurrence and inhibition of autophagy significantly reduced the apoptosis induced by the combination treatment, showing that autophagy is required for the enhanced apoptosis. Caspase-independent autophagic cell death was also induced by the combination treatment with SAHA and either BIBW2992 or WZ4002. Finally, the combined treatment with SAHA and either BIBW2992 or WZ4002 showed an enhanced anti-tumor effect on xenografts of H1975 cells in vivo. In conclusion, the combination of new generation EGFR TKIs and SAHA may be a new strategy to overcome the acquired resistance to EGFR TKIs in T790M mutant lung cancer.

Gefitinib induces cytoplasmic translocation of the CDK inhibitor p27 and its binding to a cleaved intermediate of caspase 8 in non-small cell lung cancer cells.

BACKGROUND: The epidermal growth factor receptor (EGFR) represents one of the first rationally selected molecules for targeted therapy in non-small cell lung cancer (NSCLC). Gefitinib is a reversible and highly selective tyrosine kinase inhibitor that competitively blocks the binding of adenosine triphosphate to its binding site in the tyrosine kinase domain of the EGFR. It has been found that treatment with gefitinib induces cell cycle arrest and apoptosis in NSCLC cells harboring activating EGFR mutations. Despite its clinical relevance, however, the mechanism underlying gefitinib-induced apoptosis has remained largely unknown. METHODS: We used the gefitinib-sensitive NSCLC cell line HCC827, which harbors a deletion in exon 19 of the EGFR gene, to examine the effect of gefitinib on the apoptotic machinery. RESULTS: We found that gefitinib treatment caused the NSCLC cells to undergo apoptosis following activation of the caspase 8 cascade. Expression of p27, a cyclin-dependent kinase (CDK) inhibitor whose major target is the cyclin E/CDK2 complex, was found to increase during this process, and this increase was accompanied by translocation of p27 from the nucleus to the cytoplasm. Moreover, we found that cytoplasmic p27 bound to a cleaved intermediate (p43/p41) of caspase 8 and that inhibition of cytoplasmic translocation of p27 reduced gefitinib-induced cell death in HCC827 cells. CONCLUSION: Based on our results, we conclude that gefitinib-induced apoptosis is mediated by the interaction of p27 and caspase 8 in NSCLC cells carrying an activating EGFR mutation.

Autophagy Inhibition with Monensin Enhances Cell Cycle Arrest and Apoptosis Induced by mTOR or Epidermal Growth Factor Receptor Inhibitors in Lung Cancer Cells.

BACKGROUND: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. METHODS: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. RESULTS: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-G1 phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. CONCLUSION: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

Performance status during and after radiotherapy plus concomitant and adjuvant temozolomide in elderly patients with glioblastoma multiforme.

For elderly patients with glioblastoma multiforme (GBM), radiotherapy plus concomitant and adjuvant temozolomide has resulted in longer survival. We investigated patient performance status, treatment-related toxicity and overall survival (OS) following treatment. Twenty patients aged 70years or older with a newly diagnosed GBM were treated with radiotherapy (60Gy in 16 patients and 40Gy in four patients) plus concomitant and adjuvant temozolomide. We assessed age, the extent of tumor removal, and initial performance status as possible prognostic factors for OS and good performance status following treatment. The median OS was 11.8months (95% confidence interval [CI], 8.7-14.8). The median time for patients to reach an Eastern Cooperative Oncology Group (ECOG) performance status grade 2 was 3.0months (95% CI, 2.4-3.5), and the time to ECOG performance status grade 3 was 5.8months (95% CI, 1.6-9.9). World Health Organization grade III or grade IV toxicity was observed in four patients (20%), leucopenia and thrombocytopenia was noted in two patients, and major infection occurred in two patients. Univariate analysis showed a significantly longer OS (p=0.003) and a longer time with good performance status for gross total removal (GTR) (p=0.003). An initial good performance status was related to a good performance status during and after treatment (p=0.003). Based on multivariate analysis, GTR was significantly associated with a longer OS (hazard ratio [HR]=0.236; 95% CI, 0.060-0.922, p=0.038) and a good performance status (HR=0.124; 95% CI, 0.022-0.693, p=0.017). During and after treatment, elderly patients with GBM frequently exhibited an early deterioration of performance status. Therefore, in light of a rapidly fatal illness, elderly patients should be treated to preserve and respect their quality of life.

The prognosis of anaplastic astrocytoma with radiologic necrosis mimicking glioblastoma.

Anaplastic astrocytoma (AA) sometimes shows a rapid poor course like glioblastoma. In this study, we investigated the prognosis of AA with radiologic necrosis which is the representative radiologic finding of glioblastoma. From 1995 to 2010, we operated on 26 patients who were confirmed to have AA. The male:female ratio was 13:13, and the median age was 47.23 years. The mean follow-up period was 3 years. We analyzed the prognostic significance of radiologic necrosis with age, sex, KPS, tumour location, radiologic findings, extent of removal and radiation therapy oncology group recursive partitioning analysis (RTOG-RPA) classification. The median progression-free survival (PFS) was 0.5 (± 0.17) years and the median overall survival (OS) was 1.6 (± 0.40) years. In univariate analysis, the clinical variables of younger age (p = 0.030) and RTOG-RPA class III (p = 0.043) correlated with longer PFS, and KPS (p = 0.038), radiologic necrosis (p = 0.013) and the extent of removal (p = 0.041) correlated with OS. The median OS was 1.0 (± 0.21) year in AA with radiologic necrosis compared to AA without radiologic necrosis, which showed 2.1 (± 0.29) years median OS. On multivariate analysis, there was no statistically significant prognostic factor. However, Cox's regression model revealed that gross total removal was associated with a longer OS (hazard ratio = 0.136; 95% CI, 0.018 to 1.046; p = 0.055) compared to partial removal or biopsy. Gross total resection was associated with good prognosis, and AA with radiologic necrosis had poor prognosis like glioblastoma.

Dual Inhibition of PI3K/Akt/mTOR Pathway and Role of Autophagy in Non-Small Cell Lung Cancer Cells.

BACKGROUND: The phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling axis has emerged as a novel target for cancer therapy. Agents that inhibit this pathway are currently under development for lung cancer treatment. In the present study, we have tested whether dual inhibition of PI3K/Akt/mTOR signaling can lead to enahnced antitumor effects. We have also examined the role of autophagy during this process. METHODS: We analyzed the combination effect of the mTOR inhibitor, temsirolimus, and the Akt inhibitor, GSK690693, on the survival of NCI-H460 and A549 non-small cell lung cancer cells. Cell proliferation was determined by MTT assay and apoptosis induction was evaluated by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Autophagy induction was also evaluated by acridine orange staining. Changes of apoptosis or autophagy-related proteins were evaluated by western blot analysis. RESULTS: Combination treatment with temsirolimus and GSK690693 caused synergistically increased cell death in NCI-H460 and A549 cells. This was attributable to increased induction of apoptosis. Caspase 3 activation and poly(ADP-ribose) polymerase cleavage accompanied these findings. Autophagy also increased and inhibition of autophagy resulted in increased cell death, suggesting its cytoprotective role during this process. CONCLUSION: Taken together, our results suggest that the combination of temsirolimus and GSK690693 could be a novel strategy for lung cancer therapy. Inhibition of autophagy could also be a promising method of enhancing the combination effect of these drugs.

Overexpression of Snail is associated with lymph node metastasis and poor prognosis in patients with gastric cancer.

BACKGROUND: Epithelial-mesenchymal transition (EMT) plays a significant role in tumor progression and invasion. Snail is a known regulator of EMT in various malignant tumors. This study investigated the role of Snail in gastric cancer. METHODS: We examined the effects of silenced or overexpressed Snail using lenti-viral constructs in gastric cancer cells. Immunohistochemical analysis of tissue microarrays from 314 patients with gastric adenocarcinoma (GC) was used to determine Snail's clinicopathological and prognostic significance. Differential gene expression in 45 GC specimens with Snail overexpression was investigated using cDNA microarray analysis. RESULTS: Silencing of Snail by shRNA decreased invasion and migration in GC cell lines. Conversely, Snail overexpression increased invasion and migration of gastric cancer cells, in line with increased VEGF and MMP11. Snail overexpression (≥75% positive nuclear staining) was also significantly associated with tumor progression (P < 0.001), lymph node metastases (P = 0.002), lymphovascular invasion (P = 0.002), and perineural invasion (P = 0.002) in the 314 GC patients, and with shorter survival (P = 0.023). cDNA microarray analysis revealed 213 differentially expressed genes in GC tissues with Snail overexpression, including genes related to metastasis and invasion. CONCLUSION: Snail significantly affects invasiveness/migratory ability of GCs, and may also be used as a predictive biomarker for prognosis or aggressiveness of GCs.

Unusual radiologic findings and pathologic growth patterns on choroid plexus papillomas.

OBJECTIVE: Choroid plexus papillomas (CPPs) are generally regarded as benign tumors with typical radiologic and pathologic findings. However, they sometimes have unusual findings. We have analyzed radiologic findings and pathologic growth patterns on CPPs. METHODS: The study group included 5 male and 5 female patients (age range, 3 months to 58 years : median, 29 years). The study group included 3 pediatric and 7 adult patients. All patients underwent surgery; 9 patients had a gross total resection and 1 patient had a subtotal resection. We analyzed the radiologic findings (location, size, mottle-like appearance, enhancement, calcifications, and hydrocephalus) and pathologic growth patterns (typical papillary, papillary and solid, and papillary and tubular). RESULTS: The median follow-up duration was 21.3 months (range, 4-47.8 months). There were no recurrences after initial treatment. All patients had benign CPPs. Pediatric CPPs were 3.2 cm masses (range, 2.7-4 cm) with homogeneous enhancement and a mottle-like appearance, which pathologically showed the papillary growth pattern. Hydrocephalus was present in all pediatric patients. Postoperatively, subdural hygroma had occurred in two patients. In adults, CPPs were located in the fourth ventricle in 6 patients and suprasellar area in 1 patient. The size varied from 0.5-4.2 cm. Hydrocephalus and calcifications occurred in 3 and 4 patients, respectively. Three patients showed the heterogeneous enhancement without a mottle-like appearance and pathologically showed combined papillary and solid growth in 2 patients and papillary and tubular growth in one. Postoperatively, two patients with large masses had injuries of the brainstem and underwent shunt procedures for aggravation of hydrocephalus. CONCLUSION: CPPs may show unusual radiologic findings, which preoperatively give the difficulty to be differentiated from other tumors. CPPs with unusual radiologic findings showed the combined pathologic growth patterns.

Carcinosarcoma of the gallbladder: report of two cases.

Adenocarcinoma is the predominant histological type of carcinoma of the gallbladder, accounting for more than 80% of all gallbladder carcinomas. In contrast, carcinosarcoma of the gallbladder is an extremely atypical subset of gallbladder malignancies. It is characterized by the presence of both epithelial and mesenchymal components. Currently, fewer than 100 cases have been reported in the English literature. Therefore, knowledge and experience regarding this disease are limited. Recently, we experienced two cases of gallbladder carcinosarcoma, which were diagnosed as gallbladder carcinoma based on the preoperative clinical and radiological examinations. Cholecystectomies were performed in both cases, and the malignant tumor cells included carcinomatous and sarcomatous components histologically. The final pathological diagnoses were carcinosarcoma of the gallbladder. We herein report these two cases of gallbladder carcinosarcoma and review the previous pertinent literature.

Immunohistochemical analysis of developmental neural antigen expression in the balloon cells of focal cortical dysplasia.

Balloon cells (BC) are the histological hallmarks of focal cortical dysplasia (FCD). Expression of the neural stem cell surface marker CD133 and other developmental markers was studied in the BC of FCD using formalin-fixed paraffin-embedded tissue from nine patients with FCD. Labeling indexes were calculated for all antibodies. BC were easily identified at the gray-white matter junction and they extended into the white matter. Immunoreactivity in BC was found for the following antigens in nine patients: CD133 (six patients; 22.2 ± 7.7%), CD34 (two patients; 0.4 ± 0.3%), nestin (nine patients; 37.6 ± 8.5%), vimentin (eight patients; 59.2 ± 8.7%), glial fibrillary acid protein (six patients; 34.3 ± 10.4%), microtubule-associated protein 2 (four patients; 8.3 ± 5.0%), neurofilament-middle/high (five patients; 10.2 ± 4.6%) and synaptophysin (three patients; 4.2 ± 3.3%). Neuronal nuclei (NeuN, neuron specific nuclear protein) was not expressed in BC of any patient. The results of this study suggest that BC in patients with FCD originate from glioneuronal precursor cells and that developmental defects of neuronal and glial specifications are important in the histogenesis of FCD.

Homocysteine as a risk factor for development of microalbuminuria in type 2 diabetes.

BACKGROUND: Kidney function is critical in homocysteine clearance, and plasma homocysteine level is frequently increased in patients with renal failure. On the other hand, recent studies in animals have shown that hyperhomocysteinemia induces renal injury. In this study, we determined whether hyperhomocysteinemia can be a risk factor for the development of microalbuminuria in patients with type 2 diabetes. METHODS: A nested case-control study. Of 887 patients with type 2 diabetes who did not have microalbuminuria at baseline, 76 developed microalbuminuria during follow-up (mean, 36.0 +/- 11.7 months; range, 18 to 76 months). The control group consisted of 152 age- and sex-matched subjects who did not develop microalbuminuria. Baseline plasma homocysteine concentrations were measured in stored samples. RESULTS: Baseline plasma homocysteine concentrations and mean HbA1C levels during follow-up were significantly higher in patients who developed microalbuminuria than in those who remained normoalbuminuric. Multivariate logistic regression analysis showed that baseline plasma homocysteine level and mean HbA1C were independent predictors of microalbuminuria in type 2 diabetes. CONCLUSION: Hyperhomocysteinemia was associated with increased risk of microalbuminuria in patients with type 2 diabetes supporting the concept that hyperhomocysteinemia has an etiologic role in the pathogenesis of diabetic nephropathy.