[show abstract][hide abstract] ABSTRACT: Aim: To evaluate the expression and prognostic value of two autophagy-related (Atg) proteins, Beclin-1 and Atg5, in human oral squamous cell carcinoma (OSCC) and to correlate findings with clinical outcomes.
Immunohistochemistry for Beclin-1 and Atg5 was assessed in tumor specimens from 90 patients with OSCC. Immunopositivity was semi-quantitatively scored and receiver-operating characteristic curve analysis was used to determine the cut-off positivity score.
55 (61.1%) and 52 (57.8%) cases showed positive Beclin-1 and Atg5 staining, respectively. 40 tumors (44.4%) were positive for both Beclin-1 and Atg5 expression and 23 cases (25.6%) showed absence of both proteins. Beclin-1 expression significantly correlated with tumor grade (p=0.008) and lymph node metastasis (p=0.009). The expression of Atg5 was associated with tumor grade (p=0.016), advanced clinical stage (p<0.001), large tumor size (p=0.002), and lymph node metastasis (p<0.001). A significant difference in 3-year OS (p=0.050) and TTR (p=0.049) between the patients with Beclin-1 expression and those not showing Beclin-1 expression was found whereas the difference did not reach a statistical significance for Atg5 expression. 3-year OS and TTR differed significantly between patients with dual expression and those with double-negative expression (p=0.022 and p=0.026, respectively).
Dual expression of tumor Beclin-1 and Atg5 expression may be an adverse prognostic indicator for OSCC.
Anticancer research 12/2013; 33(12):5611-6. · 1.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: Sorafenib is the first approved targeted therapeutic reagent for hepatocellular carcinoma (HCC). Here, we report that SC-60, a dimer-based sorafenib derivative, overcomes the resistance of sorafenib and shows a better anti-HCC effect in vitro and in vivo. SC-60 substantially increased SHP-1 phosphatase activity in HCC cells and purified SHP-1 proteins, suggesting that SC-60 affects SHP-1 directly. Molecular docking and truncated mutants of SHP-1 further confirmed that SC-60 interferes with the inhibitory N-SH2 domain to relieve the closed catalytic PTP domain of SHP-1. Deletion of N-SH2 domain (dN1) or point mutation (D61A) of SHP-1 abolished the effect of SC-60 on SHP-1, p-STAT3 and apoptosis. Importantly, SC-60 exhibited significant survival benefits compared to sorafenib in an HCC orthotopic model via targeting the SHP-1/STAT3-related signaling pathway. In summary, dimer derivative of sorafenib, SC-60, is a SHP-1 agonist and may be a potent reagent for HCC targeted therapy.
Molecular Cancer Therapeutics 11/2013; · 5.60 Impact Factor
[show abstract][hide abstract] ABSTRACT: Endosulfine alpha (ENSA) is an endogenous ligand of sulfonylurea receptor that was reported to be associated with an ATP-dependent potassium channel that controls insulin release and the onset of type 2 diabetes. ENSA also interacts with microtubule-associated serine/threonine-protein kinase-like (MASTL) to regulate the cell cycle. Previously, we identified ENSA as a possible bivalent gene in mesenchymal stem cells (MSCs) and hypothesized its methylation might determine cellular differentiation and transformation. Because there was no link between aberrant ENSA expression and tumorigenesis, we aimed to determine if ENSA is abnormally regulated in liver cancer and plays a role in liver cancer propagation. The epigenetic states of the ENSA promoter were evaluated in different cancer cell lines and patient samples. ENSA was overexpressed in a liver cancer cell line, and its interaction with MASTL and possible tumor suppression capabilities were also determined in cultured cells and mice. Distinct ENSA promoter methylation was observed in liver cancer (n=100 pairs) and breast cancer (n=100 pairs). ENSA was predominantly hypomethylated in liver cancer but was hypermethylated in breast cancer. Overexpressed ENSA interacts with MASTL and suppresses hepatic tumor growth. We also found that ENSA is hypermethylated in CD90-expressing (CD90(+)) cells compared to CD90 non-expressing (CD90(-)) liver cancer cells. These data reveal ENSA methylation changes during hepatic tumor evolution. Overexpressed ENSA suppresses tumor growth in an established hepatic cell line whereas hypermethylated ENSA might help maintain liver cancer initiating cells.
Biochemical and Biophysical Research Communications 11/2013; · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chondroitin sulfate proteoglycan 4 (CSPG4), a transmembrane proteoglycan originally identified in melanoma cells, has been reported to be expressed in breast cancer cells. This study was performed to examine the expression and significance of CSPG4 in a cohort of breast cancer patients. Immunohistochemical analysis of CSPG4 was performed on tissue microarrays constructed from tissue specimens from 240 breast cancer patients. CSPG4 staining was correlated with clinical and pathological characteristics, overall survival (OS), and disease recurrence. Contradicting to a previous report, our results showed that high CSPG4 expression was not related to triple-negative status of breast cancer patients. The Kaplan-Meier method showed that high CSPG4 expression was significantly associated with shorter time to recurrence (TTR). Patients with high CSPG4 expression had poorer OS and shorter TTR in a multivariate survival analysis after adjustment for stage, tumor grade, expression of estrogen receptor and progesterone receptor, and HER2 overexpression. This study showed that high CSPG4 expression correlates with disease recurrence and OS in breast cancers.
Biochemical and Biophysical Research Communications 10/2013; · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: ATG9A is an integral membrane protein required for autophagosome formation and a membrane carrier in the autophagy pathways. The present study was designed to investigate the expression of ATG9A in oral squamous cell carcinoma (OSCC). Clinically annotated tumor specimens from 90 patients with OSCC were subjected to immunohistochemistry using an antibody against ATG9A and immunoreactivity was scored using an immunoreactivity score (IRS). Scores were compared with clinical and pathologic data to assess association with outcome. Overexpression of ATG9A was defined as an IRS of ≥9 by receiver operating characteristics curve analysis and was identified in 25 (28 %) of 90 cases. ATG9A overexpression was associated with disease recurrence and overall survival (OS) in both univariate (p = 0.030 and 0.025, respectively) and multivariate (p = 0.026 and 0.038, respectively) Cox analyses. Kaplan-Meier plots also showed that patients with ATG9A overexpression had shorter 3-year OS (p = 0.017) and time to recurrence (p = 0.021) than those with low ATG9A expression. These results suggest that the presence of ATG9A in the cytoplasm of tumor cells may be an independent biomarker for disease recurrence and survival in patients with OSCC.
Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 10/2013; · 2.68 Impact Factor
[show abstract][hide abstract] ABSTRACT: Oral squamous cell carcinoma (OSCC) is a destructive disease with very poor prognosis and no effective treatment. Autophagy is a dynamic cellular process involved in various physiological processes and diseases including cancer that degrades cytoplasmic proteins and organelles. The role of autophagy in the pathogenesis of OSCC is not yet understood. Microtubule-associated protein light chains 3 (LC3) is a reliable autophagosome markers for monitoring autophagy. In the present study, LC3 expression was determined in a cohort of 90 OSCC samples by immunohistochemistry. The results were correlated with clinical and pathological characteristics of patients. High LC3 expression (N = 57; 63.3%) correlated with stage (P < .0001), tumor size (P < .0001), and lymph node involvement (P = .0003) and with an increased risk of death (P < .0001; hazard ratio, 3.59) in a univariate analysis. In the multivariate analysis adjusted for grade, stage, and alcohol, betel, and tobacco consumption, high LC3 expression retained statistical significance with regard to survival (P = .0043; hazard ratio, 2.99). The Kaplan-Meier survival curve also showed that high LC3 expression was significantly associated with poor overall survival (P = .0001). Elevated LC3 expression, which corresponds to increased level of autophagy activity, is a frequent event and an indicator of poor prognosis in human OSCC.
[show abstract][hide abstract] ABSTRACT: Signal transducers and activators of transcription 3 (STAT3) signaling is constitutively activated in various cancers including breast cancer, and has emerged as a novel potential anti-cancer target. STAT3 has been demonstrated to be a target of sorafenib, and a protein tyrosine phosphatase Src homology 2-domain containing tyrosine phosphatase 1 (SHP-1) has been demonstrated to downregulate p-STAT3 via its phosphatase activity. Here, we tested the efficacy of two sorafenib analogues, SC-1 and SC-43, in breast cancer cells and examined the drug mechanism.
Breast cancer cell lines were used for in vitro studies. Cell viability was examined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was examined by flow cytometry and western blot. Signal transduction pathways in cells were assessed by western blot. In vivo efficacy of sorafenib, SC-1 and SC-43 were tested in xenografted nude mice.
SC-1 and SC-43 induced more potent apoptosis than sorafenib, in association with downregulation of p-STAT3 and its downstream proteins cyclin D1 and survivin in a dose-dependent manner in breast cancer cell lines (HCC-1937, MDA-MB-468, MDA-MB-231, MDA-MB-453, SK-BR3, MCF-7). Overexpression of STAT3 in MDA-MB-468 cells protected cells from apoptosis induced by sorafenib, SC-1, and SC-43. Moreover, SC-1 and SC-43 upregulated SHP-1 activity to a greater extent than sorafenib as measured by in vitro phosphatase assays. Knockdown of SHP-1 by siRNA reduced apoptosis induced by SC-1 and SC-43. Importantly, SC-1 and SC-43 showed more efficacious antitumor activity and p-STAT3 downregulation than sorafenib in MDA-MB-468 xenograft tumors.
Novel sorafenib analogues SC-1 and SC-43 induce apoptosis through SHP-1 dependent STAT3 inactivation and demonstrate greater potency than sorafenib in human breast cancer cells.
Breast cancer research: BCR 08/2013; 15(4):R63. · 5.87 Impact Factor
[show abstract][hide abstract] ABSTRACT: Sorafenib is the first approved targeted therapeutic reagent for hepatocellular carcinoma (HCC). Here, we report that Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1) is a major target of sorafenib and generates a series of sorafenib derivatives to search for potent SHP-1 agonists that may act as better anti-HCC agents than sorafenib. Sorafenib increases SHP-1 activity by direct interaction and impairs the association between the N-SH2 domain and the catalytic protein tyrosine phosphatase domain of SHP-1. Deletion of the N-SH2 domain (dN1) or point mutation (D61A) of SHP-1 abolished the effect of sorafenib on SHP-1, phosphorylated signal transducer and activator of transcription 3 (p-STAT3), and apoptosis, suggesting that sorafenib may affect SHP-1 by triggering a conformational switch relieving its autoinhibition. Molecular docking of SHP-1/sorafenib complex confirmed our findings in HCC cells. Furthermore, novel sorafenib derivatives SC-43 and SC-40 displayed more-potent anti-HCC activity than sorafenib, as measured by enhanced SHP-1 activity, inhibition of p-STAT3, and induction of apoptosis. SC-43 induced substantial apoptosis in sorafenib-resistant cells and showed better survival benefits than sorafenib in orthotopic HCC tumors. Conclusion: In this study, we identified SHP-1 as a major target of sorafenib. SC-43 and SC-40, potent SHP-1 agonists, showed better anti-HCC effects than sorafenib in vitro and in vivo. Further clinical investigation is warranted. (Hepatology 2013;).
[show abstract][hide abstract] ABSTRACT: In previous research, we found α-enolase to be inversely correlated with progression-free and overall survival in lung cancer patients and detected α-enolase on the surface of lung cancer cells. Based on these findings, we hypothesized that surface α-enolase has a significant role in cancer metastasis and tested this hypothesis in the current study. We found that α-enolase was co-immunoprecipitated with urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen in lung cancer cells and interacted with these proteins in a cell-free dot blotting assay, which can be interrupted by α-enolase-specific antibody. α-Enolase in lung cancer cells co-localized with these proteins and was present at the site of pericellular degradation of extracellular matrix components. Treatment with antibody against α-enolase in vitro suppressed cell-associated plasminogen and matrix metalloproteinase activation, collagen and gelatin degradation, and cell invasion. Examination of the effect of treatment with shRNA plasmids revealed that down regulation of α-enolase decreases extracellular matrix degradation by and the invasion capacity of lung cancer cells. Adoptive transfer of α-enolase-specific antibody to mice resulted in accumulation of antibody in subcutaneous tumor and inhibited the formation of tumor metastasis in lung and bone. This study demonstrated that surface α-enolase promotes extracellular matrix degradation and invasion of cancer cells and that targeting surface α-enolase is a promising approach to suppress tumor metastasis.
PLoS ONE 07/2013; 8(7):e69354. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Autophagy is a self-catabolic mechanism that degrades unnecessary cellular components through lysosomal enzymes. Beclin-1, an autophagy-related protein, establishes the first connection between autophagy and tumorigenesis. The purpose of this study is to assess the Beclin-1 expression pattern and to determine its prognostic significance in patients with malignant canine mammary tumor (CMT).
BMC Veterinary Research 04/2013; 9(1):75. · 1.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue tumor of uncertain histogenesis, occurring predominantly in deep soft tissues of the extremities. Typically, OFMT presents in adults on the extremities or trunk, as a deep soft tissue mass. Less appreciated is the fact that OFMT may also present as a mass in the superficial subcutis or dermis. We herein report a female who presented with an asymptomatic subcutaneous nodule on the left thigh for 3 years, and who was diagnosed as having typical ossifying fibromyxoid tumor, by unique histopathologic and immunohistochemical studies. Most reported cases have pursued a benign clinical course. However, recent literature emphasized the existence of morphologically atypical and clinically malignant cases of OFMTs. Pathologic criteria for malignancy have been proposed, and reclassification of these tumors as tumors of intermediate malignancy, raise our attention while coping with OFMT clinically.
[show abstract][hide abstract] ABSTRACT: BRCA1-associated breast cancers are associated with particular features such as early onset, poor histological differentiation, and hormone receptor negativity. Previous studies conducted in Taiwanese population showed that the mutation of BRCA1 gene does not play a significant role in the occurrence of breast cancer. The present study explored methylation of BRCA1 promoter and its relationship to clinical features and outcome in Taiwanese breast cancer patients. Tumor specimens from a cohort of 139 early-stage breast cancer patients were obtained during surgery before adjuvant treatment for DNA extraction. Methylation of BRCA1 promoter region was determined by methylation-specific PCR and the results were related to clinical features and outcome of patients using statistical analysis. Methylation of the BRCA1 promoter was detected in 78 (56%) of the 139 tumors. Chi-square analysis indicated that BRCA1 promoter methylation correlated significantly with triple-negative (ER-/PR-/HER2-) status of breast cancer patients (p = 0.041). The Kaplan-Meier method showed that BRCA1 promoter methylation was significantly associated with poor overall survival (p = 0.026) and disease-free survival (p = 0.001). Multivariate analysis which incorporated variables of patients' age, tumor size, grade, and lymph node metastasis revealed that BRCA1 promoter methylation was associated with overall survival (p = 0.27; hazard ratio, 16.38) and disease-free survival (p = 0.003; hazard ratio, 12.19). Our findings underscore the clinical relevance of the methylation of BRCA1 promoter in Taiwanese patients with early-stage breast cancer.
PLoS ONE 01/2013; 8(2):e56256. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The proto-oncogene KIT encodes a receptor tyrosine kinase which has been shown to be upregulated in canine melanomas. KIT mutations lead to constitutive phosphorylation and activation of KIT in the absence of ligand binding. The presence of KIT mutations and KIT protein expression was examined in a cohort of 49 dogs with canine malignant melanoma. An exon 11 synonymous nucleotide 1743C→T mutation was identified in five cases in which one also harbored a L579P mutation. Tumors that harbored the KIT exon 11 mutation(s) correlated significantly with disease recurrence (P=0.05). All 36 melanomas available for immunohistochemical analysis showed either weak (16 cases, 44.4%) or strong (20 cases, 55.6%) expression of the KIT protein. The five KIT mutation carriers were all strongly positive for KIT by immunohistochemical staining. These findings suggest that a subset of canine malignant melanomas harbors a KIT exon 11 mutation.
The Veterinary Journal 10/2012; · 2.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND & PURPOSE: Previously, we have shown that sorafenib sensitizes hepatocellular carcinoma (HCC) to TRAIL-induced apoptosis. Here, we report that sorafenib and SC-49 sensitize HCC cells to CS-1008, a novel anti-human death receptor 5 antibody. EXPERIMENTAL APPROACH: HCC cell lines (PLC5, Huh-7, and Hep3B) were treated with CS-1008 and/or sorafenib and analyzed in terms of apoptosis, signal transductions. KEY RESULTS: SC-49 is a sorafenib derivative which is devoid of kinase inhibition activity. Our data indicated that sorafenib as well as SC-49 down-regulated the phosphorylation of signal transducers and activators of transcription 3 (p-STAT3) at Tyr 705 and subsequently reduced the protein levels of STAT3-regulated proteins, Mcl-1, survivin and cylcin D1, in CS-1008-treated HCC cells. Knockdown of STAT3 by RNA-interference overcame apoptotic resistance to CS-1008 in HCC cells, and ectopic expression of STAT3 in HCC cells abolished the sensitizing effect of sorafenib or SC-49 on CS-1008-induced apoptosis, indicating that inhibition of STAT3 mediates the effects of the combination. Importantly, inhibition of SHP-1 by adding a specific SHP-1 inhibitor reduced the effects of SC-49 and CS-1008 on p-STAT3 and apoptosis, whereas co-treatment of CS-1008 and SC-49 increased the activity of SHP-1, suggesting that SHP-1 mediated the combinational effect of CS-1008 and SC-49 in HCC. Moreover, the combination of CS-1008 and SC-49 inhibited HCC xenograft tumor growth in vivo. CONCLUSIONS & IMPLICATIONS: Sorafenib and its derivative SC-49 sensitize HCC to CS-1008 through SHP-1-dependent STAT3 inactivation.
British Journal of Pharmacology 09/2012; · 5.07 Impact Factor
[show abstract][hide abstract] ABSTRACT: Protein kinase C beta II (PKCβII) is a member of the family of serine/threonine kinases which are involved in tumor formation and progression. This study investigated the significance of PKCβII in oral squamous cell carcinoma (OSCC).
The expression of PKCβII was determined in tumors from 59 patients with OSCC using immunohistochemistry and was correlated with patients' clinical characteristics and outcomes.
Twenty-six cases (44%) exhibited nuclear PKCβII staining. High nuclear PKCβII expression was significantly associated with the consumption of betel quid (p=0.015) and alcohol (p=0.024) in OSCC. Kaplan-Meier analysis revealed a shorter time-to-recurrence in patients with high nuclear PKCβII expression (p=0.018). In multivariate analysis for recurrence, high nuclear staining of PKCβII remained an independent adverse prognostic factor (hazard ratio=2.3, p=0.016).
The present study provides evidence of the potential prognostic value of PKCβII analysis in OSCC.
Anticancer research 09/2012; 32(9):3987-91. · 1.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: Polycomb-group proteins mark specific chromatin conformations in embryonic and somatic stem cells that are critical for maintenance of their "stemness". These proteins also mark altered chromatin modifications identified in various cancers. In normal differentiated cells or advanced cancerous cells, these polycomb-associated loci are frequently associated with increased DNA methylation. It has thus been hypothesized that changes in DNA methylation status within polycomb-associated loci may dictate cell fate and that abnormal methylation within these loci may be associated with tumor development. To assess this, we examined the methylation states of four polycomb target loci -Trip10, Casp8AP2, ENSA, and ZNF484 - in liver cancer. These four targets were selected because their methylation levels are increased during mesenchymal stem cell-to-liver differentiation. We found that these four loci were hypomethylated in most early-stage liver cancer specimens. For comparison, two non-polycomb tumor suppressor genes, HIC1 and RassF1A, were also examined. Whereas the methylation level of HIC1 did not differ significantly between normal and tumor samples, RassF1A was significantly hypermethylated in liver tumor samples. Unsupervised clustering analysis classified the methylation changes within polycomb and non-polycomb targets to be independent, indicating independent epigenetic evolution. Thus, pre-deposited polycomb marks within somatic stem cells may contribute to the determination of methylation changes during hepatic tumorigenesis.
Biochemical and Biophysical Research Communications 07/2012; 425(2):290-6. · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Casp8AP2 contains a FLASH functional domain and is critical for the formation of death complex and the relay of death signal into the cells. Genetic defects in Casp8AP2 are associated with several diseases. A CpG island within the Casp8AP2 promoter is differentially regulated during somatic stem cell differentiation, and aberrant DNA methylation within the Casp8AP2 promoter has been reported in cancers. We hypothesized that abnormal DNA methylation of Casp8AP2 promoter might contribute to prolonged cellular survival or drug resistance in cancer. The epigenetic state within the Casp8AP2 promoter was then determined in different cancer cell lines and patient samples by methylation-specific PCR. Targeted Casp8AP2 methylation within normal and tumor cells was performed to see whether methylation promoted drug resistance. We found differential Casp8AP2 methylation among the normal and tumoral samples. Global demethylation in a platinum drug-resistant human gastric cancer cell line reversed Casp8AP2 methylation and diminished drug resistance. Targeted methylation of the Casp8AP2 promoter in somatic stem cells and cancer cells increased their resistance to drugs including platinum drugs. These data demonstrate that methylation within the Casp8AP2 promoter correlates with the development of drug resistance and might serve as a biomarker and treatment target for drug resistance in cancer cells.
Biochemical and Biophysical Research Communications 05/2012; 422(4):578-85. · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Triple negative breast cancer (TNBC) is very aggressive and currently has no specific therapeutic targets, such as hormone receptors or human epidermal growth factor receptor type 2 (HER2); therefore, prognosis is poor. Bortezomib, a proteasome inhibitor, may exert efficacy in TNBC through its multiple cellular effects. Here, we tested the efficacy of bortezomib and examined the drug mechanism in breast cancer cells.
Five breast cancer cell lines: TNBC HCC-1937, MDA-MB-231, and MDA-MB-468; HER2-overexpressing MDA-MB-453; and estrogen receptor positive MCF-7 were used for in vitro studies. Apoptosis was examined by both flow cytometry and Western Blot. Signal transduction pathways in cells were assessed by Western Blot. Gene silencing was done by small interfering RNA (siRNA). In vivo efficacy of bortezomib was tested in nude mice with breast cancer xenografts. Immunohistochemical study was performed on tumor tissues from patients with TNBC.
Bortezomib induced significant apoptosis, which was independent of its proteasome inhibition, in the three TNBC cell lines, but not in MDA-MB-453 or MCF-7 cells. Furthermore, cancerous inhibitor of protein phosphatase 2A (CIP2A), a cellular inhibitor of protein phosphatase 2A (PP2A), mediated the apoptotic effect of bortezomib. We showed that bortezomib inhibited CIP2A in association with p-Akt downregulation in a dose- and time-dependent manner in all sensitive TNBC cells, whereas no alterations in CIP2A expression and p-Akt were noted in bortezomib-resistant cells. Overexpression of CIP2A upregulated p-Akt and protected MDA-MB-231 and MDA-MB-468 cells from bortezomib-induced apoptosis, whereas silencing CIP2A by siRNA overcame the resistance to bortezomib-induced apoptosis in MCF-7 cells. In addition, bortezomib downregulated CIP2A mRNA but did not affect the degradation of CIP2A protein. Furthermore, bortezomib exerted in vivo antitumor activity in HCC-1937 xenografted tumors, but not in MCF-7 tumors. Bortezomib downregulated CIP2A expression in the HCC-1937 tumors but not in the MCF-7 tumors. Importantly, CIP2A expression is readily detectable in tumor samples from TNBC patients.
CIP2A is a major determinant mediating bortezomib-induced apoptosis in TNBC cells. CIP2A may thus be a potential therapeutic target in TNBC.
Breast cancer research: BCR 04/2012; 14(2):R68. · 5.87 Impact Factor