Epidermal growth factor receptor expression in high-grade osteosarcomas is associated with a good clinical outcome

Downregulation of PRKCI inhibits osteosarcoma cell growth by inactivating the Akt/mTOR signaling pathway

PRKCI is abnormally expressed in various cancers, but its role in osteosarcoma is unknown. This study aimed to explore the biological function of PRKCI in osteosarcoma and its potential molecular mechanism. PRKCI expression was evaluated in osteosarcoma cell lines using Western blot analysis and reverse transcription PCR. The CCK-8 assay, colony formation assay, flow cytometry, Transwell assay, and wound-healing assay were used to detect the proliferation, colony-forming capacity, cell cycle, migration, and invasion of osteosarcoma cells when PRKCI was overexpressed or knocked down. The interaction between PRKCI and SQSTM1 was explored using immunoprecipitation. Finally, the protein molecule expression of the Akt/mTOR signaling pathway in osteosarcoma was detected when PRKCI was knocked down. Our study found that PRKCI was overexpressed in osteosarcoma cell lines. The overexpression of PRKCI promoted the proliferation and colony-forming capacity of osteosarcoma cells, while silencing PRKCI inhibited the proliferation, colony-forming capacity, migration, and invasion of osteosarcoma cells and arrested the cell cycle at the G2/M phase. Both PRKCI and SQSTM1 were overexpressed in osteosarcoma. The expression of PRKCI was only related to histological type, while that of SQSTM1 was not related to clinical characteristics. The expression of PRKCI and SQSTM1 in osteosarcoma was higher than that in chondrosarcoma. Knockdown of PRKCI inhibited the proliferation of osteosarcoma cells by inactivating the Akt/mTOR signaling pathway, suggesting that PRKCI was a potential target for osteosarcoma therapy.

Molecular Analysis of the Superior Efficacy of a Dual Epidermal Growth Factor Receptor (EGFR)-DNA-Targeting Combi-Molecule in Comparison with Its Putative Prodrugs 6-Mono-Alkylamino- and 6,6-Dialkylaminoquinazoline in a Human Osteosarcoma Xenograft Model

Background: ZR2002 is a dual EGFR-DNA-targeting combi-molecule that carries a chloroethyl group at the six-position of the quinazoline ring designed to alkylate DNA. Despite its good pharmacokinetics, ZR2002 is metabolized in vivo into dechlorinated metabolites, losing the DNA-alkylating function required to damage DNA. To increase the DNA damage activity in tumor cells in vivo, we compared ZR2002 with two of its 6-N,N-disubstituted analogs: "JS61", with a nitrogen mustard function at the six-position of the quinazoline ring, and "JS84", with an N-methyl group. Methods: Tumor xenografts were performed with the human Saos-2 osteosarcoma cell line expressing EGFR. Mice were treated with ZR2002, JS84 or JS61, and the tumor burden was measured with a caliper and CT/PET imaging. Drug metabolism was analyzed with LC-MS. EGFR and ɣ-H2AX phosphorylation were quantified via Western blot analysis and immunohistochemistry. Results: In vivo analysis showed that significant tumor growth inhibition was only achieved when ZR2002 was administered in its naked form. The metabolic dealkylation of JS61 and JS84 did not release sufficient concentrations of ZR2002 for the intratumoral inhibition of P-EGFR or enhanced levels of P-H2AX. Conclusions: The results in toto suggest that intratumoral concentrations of intact ZR2002 are correlated with the highest inhibition of P-EGFR and induction of DNA damage in vivo. ZR2002 may well represent a good drug candidate for the treatment of EGFR-expressing osteosarcoma.

Defucosylated Anti-Epidermal Growth Factor Receptor Monoclonal Antibody (134-mG2a-f) Exerts Antitumor Activities in Mouse Xenograft Models of Canine Osteosarcoma

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein. Although EGFR is physiologically essential in normal cells, it contributes to tumor malignancy through gene amplification and/or protein overexpression, which augment signaling cascades in tumor cells. We previously developed an anti-human EGFR (hEGFR) monoclonal antibody (mAb), EMab-134 (mouse IgG₁, kappa), which detects hEGFR and dog EGFR (dEGFR) with high sensitivity and specificity. The mouse IgG_2a version of EMab-134 (134-mG_2a) has antitumor effects toward mouse xenografts of hEGFR-expressing oral squamous cell carcinomas. Furthermore, 134-mG_2a-f, the defucosylated version of 134-mG_2a, exhibits antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in dEGFR-overexpressed CHO-K1 (CHO/dEGFR) cells and antitumor activities in mouse xenografts of CHO/dEGFR cells. Herein, the reactivity of 134-mG_2a-f against canine cancer cells with endogenous dEGFR was first examined by flow cytometry and immunocytochemistry. In vitro analysis demonstrated that 134-mG_2a-f highly exerted ADCC and CDC for a canine osteosarcoma cell line, D-17, which expresses endogenous dEGFR. Moreover, in vivo administration of 134-mG_2a-f significantly suppressed the development of D-17 compared with the results in response to control mouse IgG. These results suggest that 134-mG_2a-f exerts antitumor effects against dEGFR-expressing canine cancers, and could be valuable as part of an antibody treatment regimen for them.

Positive Feedback Regulation of Circular RNA Hsa_circ_0000566 and HIF-1α promotes Osteosarcoma Progression and Glycolysis Metabolism

Hypoxia is an indispensable factor for cancer progression and is closely associated with the Warburg effect. Circular RNAs (CircRNA) have garnered considerable attention in molecular malignancy therapy as they are potentially important modulators. However, the roles of circRNAs and hypoxia in osteosarcoma (OS) progression have not yet been elucidated. This study reveals the hypoxia-sensitive circRNA, Hsa_circ_0000566, that plays a crucial role in OS progression and energy metabolism under hypoxic stress. Hsa_circ_0000566 is regulated by hypoxia-inducible factor-1α (HIF-1α) and directly binds to it as well as to the Von Hippel-Lindau (VHL) E3 ubiquitin ligase protein. Consequentially, binding between VHL and HIF-1α is impeded. Furthermore, Hsa_circ_0000566 contributes to OS progression by binding to HIF-1α (while competing with VHL) and by confers protection against HIF-1α against VHL-mediated ubiquitin degradation. These findings demonstrate the existence of a positive feedback loop formed by HIF-1α and Hsa_circ_0000566 and the key role they play in OS glycolysis. Taken together, these data indicate the significance of Hsa_circ_0000566 in the Warburg effect and suggest that Hsa_circ_0000566 could be a potential therapeutic target to combat OS progression.

Defucosylated Mouse-Dog Chimeric Anti-EGFR Antibody Exerts Antitumor Activities in Mouse Xenograft Models of Canine Tumors

The epidermal growth factor receptor (EGFR) contributes to tumor malignancy via gene amplification and protein overexpression. Previously, we developed an anti-human EGFR (hEGFR) monoclonal antibody, namely EMab-134, which detects hEGFR and dog EGFR (dEGFR) with high sensitivity and specificity. In this study, we produced a defucosylated mouse–dog chimeric anti-EGFR monoclonal antibody, namely E134Bf. In vitro analysis revealed that E134Bf highly exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against a canine osteosarcoma cell line (D-17) and a canine fibroblastic cell line (A-72), both of which express endogenous dEGFR. Moreover, in vivo administration of E134Bf significantly suppressed the development of D-17 and A-72 compared with the control dog IgG in mouse xenografts. These results indicate that E134Bf exerts antitumor effects against dEGFR-expressing canine cancers and could be valuable as part of an antibody treatment regimen for dogs.

Prognostic Signature of Osteosarcoma Based on 14 Autophagy-Related Genes

Background: Osteosarcoma is a common malignancy of bone with inferior survival outcome. Autophagy can exert multifactorial influence on tumorigenesis and tumor progression. However, the specific function of genes related to autophagy in the prognosis of osteosarcoma patients remains unclear. Herein, we aimed to explore the association of genes related to autophagy with the survival outcome of osteosarcoma patients.

Methods: The autophagy-associated genes that were related to the prognosis of osteosarcoma were optimized by LASSO Cox regression analysis. The survival of osteosarcoma patients was forecasted by multivariate Cox regression analysis. The immune infiltration status of 22 immune cell types in osteosarcoma patients with high and low risk scores was compared by using the CIBERSORT tool.

Results: The risk score model constructed according to 14 autophagy-related genes (ATG4A, BAK1, BNIP3, CALCOCO2, CCL2, DAPK1, EGFR, FAS, GRID2, ITGA3, MYC, RAB33B, USP10, and WIPI1) could effectively predict the prognosis of patients with osteosarcoma. A nomogram model was established based on risk score and metastasis.

Conclusion: Autophagy-related genes were identified as pivotal prognostic signatures, which could guide the clinical decision making in the treatment of osteosarcoma.

Blue LED causes autophagic cell death in human osteosarcoma by increasing ROS generation and dephosphorylating EGFR

Osteosarcoma (OS) is the most common primary malignant bone tumour in adolescence. Lately, light‐emitting diodes (LED)‐based therapy has emerged as a new promising approach for several diseases. However, it remains unknown in human OS. Here, we found that the blue LED irradiation significantly suppressed the proliferation, migration and invasion of human OS cells, while we observed blue LED irradiation increased ROS production through increased NADPH oxidase enzymes NOX2 and NOX4, as well as decreased Catalase (CAT) expression levels. Furthermore, we revealed blue LED irradiation‐induced autophagy characterized by alterations in autophagy protein markers including Beclin‐1, LC3‐II/LC3‐I and P62. Moreover, we demonstrated an enhanced autophagic flux. The blockage of autophagy displayed a remarkable attenuation of anti‐tumour activities of blue LED irradiation. Next, ROS scavenger N‐acetyl‐L‐cysteine (NAC) and NOX inhibitor diphenyleneiodonium (DPI) blocked suppression of OS cell growth, indicating that ROS accumulation might play an essential role in blue LED‐induced autophagic OS cell death. Additionally, we observed blue LED irradiation decreased EGFR activation (phosphorylation), which in turn led to Beclin‐1 release and subsequent autophagy activation in OS cells. Analysis of EGFR colocalization with Beclin‐1 and EGFR‐immunoprecipitation (IP) assay further revealed the decreased interaction of EGFR and Beclin‐1 upon blue LED irradiation in OS cells. In addition, Beclin‐1 down‐regulation abolished the effects of blue LED irradiation on OS cells. Collectively, we concluded that blue LED irradiation exhibited anti‐tumour effects on OS by triggering ROS and EGFR/Beclin‐1‐mediated autophagy signalling pathway, representing a potential approach for human OS treatment.

Targeting Molecular Mechanisms Underlying Treatment Efficacy and Resistance in Osteosarcoma: A Review of Current and Future Strategies

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Due to micrometastatic spread, radical surgery alone rarely results in cure. Introduction of combination chemotherapy in the 1970s, however, dramatically increased overall survival rates from 20% to approximately 70%. Unfortunately, large clinical trials aiming to intensify treatment in the past decades have failed to achieve higher cure rates. In this review, we revisit how the heterogenous nature of osteosarcoma as well as acquired and intrinsic resistance to chemotherapy can account for stagnation in therapy improvement. We summarise current osteosarcoma treatment strategies focusing on molecular determinants of treatment susceptibility and resistance. Understanding therapy susceptibility and resistance provides a basis for rational therapy betterment for both identifying patients that might be cured with less toxic interventions and targeting resistance mechanisms to sensitise resistant osteosarcoma to conventional therapies.

Afatinib is active in osteosarcoma in osteosarcoma cell lines

PURPOSE

Osteosarcoma is the most common bone tumor, mainly affecting adolescents and young adults, and metastatic disease has poor outcomes with a dismal overall survival. Currently, chemotherapy is the standard of care with limited results, finding that new therapies could improve these outcomes. Preclinical and clinical studies have suggested a possible important role of ErbB pathway aberrations in osteosarcoma etiology. The present study shows the effect of afatinib, an irreversible ErbB family blocker in osteosarcoma cell lines.

METHODS

Within a panel of human osteosarcoma cell lines, we addressed cell viability assay using afatinib at increasing concentrations. Motility was measured in wound-healing assays and invasion capacity was assessed in Transwell chamber assays. Finally, to monitor ErbB pathway modulation by afatinib and related compounds, we used Western blot analyses.

RESULTS

Cell viability inhibition, as well as a reduction of motility and migration of osteosarcoma cell line were observed after treatment with afatinib. Likewise, in the HOS cell line, afatinib decreased phosphorylation of key components in the ErbB signaling pathway.

CONCLUSIONS

Afatinib shows relevant antitumor effect in several osteosarcoma cell lines, as it causes a significant impact on cell viability, motility, and migration with a significant decrease in the activation of ErbB pathway activity.

Clinicopathological value of ErbB2 gene and protein expression in osteochondroma

OBJECTIVE

The aim of this study was to investigate ErbB2 expression in osteochondroma and its relationship with clinicopathologic features of osteochondroma, so as to identify a new biomarker for the malignant transformation potential of osteochondroma.

METHODS

Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were used to investigate the expression status of ErbB2 protein and gene in 30 osteochondroma tissues and 20 non-neoplastic bone tissues. The association of ErbB2 gene and protein expression with clinicopathological parameters of osteochondroma was analyzed by using the χ2 test and Fishers exact test.

RESULTS

ErbB2 protein was found to be over-expressed in 4 of 30 (13.3%) osteochondromas and 1 of 20 (5%) non-neoplastic bone samples, which were not statistically significant (p=0.336). However, 13 of the 30 (43.3%) osteochondromas showed ErbB2 gene amplification, which was failed to be observed in any of the non-neoplastic bone tissue. ErbB2 gene amplification in osteochondroma was significantly higher compared with that in non-neoplastic bone tissue (p=0.001). In addition, the ErbB2 gene amplification was closely associated with clinical pathological parameters of osteochondroma, including high expression of cellularity (p=0.001), presence of binucleated cells (p=0.001), nuclear pleomorphism (p=0.003), calcification (p=0.002), nodularity (p=0.002), necrosis (p=0.009) and cartilage thickness (p=0.026). The association of the gene amplification with other clinicopathological parameters of osteochondroma, including permeation of trabecular bone, cystic/mucoid changes, mitosis, radiographic appearance, cap volume and subtype of osteochondroma was not observed. The over-expression of ErbB2 protein was not found to be associated with the above stated clinical pathological parameters of osteochondroma.

CONCLUSION

ErbB2 gene amplification was associated with adverse clinicopathological status of osteochondroma and could serve as an index for malignant conversion of osteochondroma. Further research is required to verify the predictive values of ErbB2 for osteochondroma.

LEVEL OF EVIDENCE

Level IV, Diagnostic Study.

EGFR is required for FOS-dependent bone tumor development via RSK2/CREB signaling

Osteosarcoma (OS) is a rare tumor of the bone occurring mainly in young adults accounting for 5% of all childhood cancers. Because of the limited therapeutic options, there has been no survival improvement for OS patients in the past 40 years. The epidermal growth factor receptor (EGFR) is highly expressed in OS; however, its clinical relevance is unclear. Here, we employed an autochthonous c‐Fos‐dependent OS mouse model (H2‐c‐fosLTR) and human OS tumor biopsies for preclinical studies aimed at identifying novel biomarkers and therapeutic benefits of anti‐EGFR therapies. We show that EGFR deletion/inhibition results in reduced tumor formation in H2‐c‐fosLTR mice by directly inhibiting the proliferation of cancer‐initiating osteoblastic cells by a mechanism involving RSK2/CREB‐dependent c‐Fos expression. Furthermore, OS patients with co‐expression of EGFR and c‐Fos exhibit reduced overall survival. Preclinical studies using human OS xenografts revealed that only tumors expressing both EGFR and c‐Fos responded to anti‐EGFR therapy demonstrating that c‐Fos can be considered as a novel biomarker predicting response to anti‐EGFR treatment in OS patients.

MAT2B promotes proliferation and inhibits apoptosis in osteosarcoma by targeting epidermal growth factor receptor and proliferating cell nuclear antigen

Osteosarcoma (OS) is the most commonly diagnosed bone tumor in young people with poor prognosis. At present, the mechanisms underlying tumorigenesis in OS are not well understood. The methionine adnosyltransferase 2B (MAT2B) gene encodes the regulatory subunit of methionine adenosyltransferase (MAT). Recent studies demonstrated that it is highly expressed in a number of human malignancies; however, is undefined in OS. In the present study, MAT2B expression was investigated in tumor samples and cell lines. In vivo and in vitro, lentivirus‑mediated small hairpin RNA was constructed to target the MAT2B gene and examine the role of MAT2B in OS proliferation. Microarray analysis was performed to examine the possible downstream molecular target of MAT2B in OS. MAT2B was markedly increased in OS specimens compared with the normal bone tissues, and it was additionally abundantly expressed in OS cell lines. Inhibition of MAT2B expression caused a marked decrease in proliferation and significant increase in apoptosis. In vivo, MAT2B silencing significantly inhibited OS cell growth. Microarray analysis suggested that epidermal growth factor receptor (EGFR) and proliferating cell nuclear antigen (PCNA) may function as downstream targets of MAT2B in OS, as confirmed by reverse transcription‑quantitative polymerase chain reaction assays and western blotting. Collectively, these results suggested that MAT2B serves a critical role in the proliferation of OS by regulating EGFR and PCNA and that it may be a potential therapeutic target and prognostic factor of OS.

Analyzing the disease module associated with osteosarcoma via a network- and pathway-based approach

Osteosarcoma is the most common type of primary malignant bone tumor observed in children and adolescents. The aim of the present study was to identify an osteosarcoma-related gene module (OSM) by looking for a dense module following the integration of signals from genome-wide association studies (GWAS) into the human protein-protein interaction (PPI) network. A dataset of somatic mutations in osteosarcoma was obtained from the dbGaP database and their testing P-values were incorporated into the PPI network from a recent study using the dmGWAS bioconductor package. An OSM containing 201 genes (OS genes) and 268 interactions, which were closely associated with immune response, intracellular signal transduction and cell activity was identified. Topological analysis of the OSM identified 11 genes, including APP, APPBP2, ATXN1, HSP90B1, IKZF1, KRTAP10-1, PAK1, PDPK1, SMAD4, SUZ12 and TP53 as potential diagnostic biomarkers for osteosarcoma. The overall survival analysis of osteosarcoma for those 11 genes based on a dataset from the Cancer Genome Atlas, identified APP, HSP90B1, SUZ12 and IKZF1 as osteosarcoma survival-related genes. The results of the present study should be helpful in understanding the diagnosis and treatment of osteosarcoma and its underlying mechanisms. In addition, the methodology used in the present study may be suitable for the analysis of other types of disease.

Prognostic significance of the expression of HER family members in primary osteosarcoma

The prognosis of patients with metastatic osteosarcoma is poor and has shown no significant improvement in nearly 20 years. The human epidermal growth factor (EGF) receptor (HER) family is frequently overexpressed in the majority of human carcinomas, and is involved in promoting the proliferation and survival of cancer cells. However, the role of EGFR and HER-2 expression in osteosarcoma survival remains controversial and no previous study has simultaneously investigated the association of the expression of all the four HER family members with the prognostic significance of osteosarcoma. Therefore, the present study investigated the expression levels of the complete members of the HER family in osteosarcoma specimens, as well as their associations with the clinicopathological parameters, progression-free survival (PFS) and overall survival (OS) time of patients with osteosarcoma. The expression of HER family members was detected in osteosarcoma tumor specimens from 60 patients using immunohistochemistry. The association of the expression of HER receptors in osteosarcoma with clinicopathological parameters was analyzed using χ² test and Fishers exact test. Survival analyses were evaluated by Kaplan-Meier method and Cox proportional hazards regression model. Overall, 18 (30%), 13 (22%), 23 (38%) and 19 (32%) patients presented with high expression of EGFR, HER-2, HER-3 and HER-4, respectively, and the co-expression of 2, 3 and all 4 members of the HER family was observed. High expression of EGFR and HER-4 was associated with distant metastasis. High HER-3 expression was significantly associated with an advanced Enneking stage and distant metastasis. Multivariate analysis demonstrated that the expression of EGFR, HER-3, HER-4, EGFR/HER-3, EGFR/HER-4 and HER-3/HER-4 was an independent predictor of poor PFS and OS time in osteosarcoma patients with stage I–IIB disease. In patients with stage IIB osteosarcoma, the expression of HER-4 and EGFR/HER-4 demonstrated a more significant effect on PFS and OS time. In conclusion, therapies targeting EGFR, HER-3 and HER-4 may provide promising strategies for primary osteosarcoma.

The Prognostic Role of Ezrin and HER2/neu Expression in Osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor in Egypt. Ezrin is involved in cell adhesion to the extracellular matrix and in cell-cell interactions facilitating metastasis. HER2/neu is overexpressed in breast cancer and other types of cancer. This study aimed to assess the expression of ezrin and HER2/neu in 57 primary osteosarcoma cases and to correlate their expression with the available clinicopathologic parameters and the overall, metastasis-free and event-free survival. Both ezrin and HER2/neu were not expressed in the normal bone and they were upregulated in 82.5% and 71.9% of osteosarcoma, respectively. Positive ezrin expression was significantly associated with young age (below 25 y) (P=0.01), high grade (P=0.001), and short survival time (P=0.0001). Positive HER2/neu expression was significantly associated with high-grade osteosarcoma (P=0.04). Membranous HER2/neu expression was the only factor that showed significant impact on metastasis-free (P=0.002) and event-free survival (P=0.002). Ezrin was significantly correlated with HER2/neu expression (P=0.02). Advanced stage (P=0.0001), metastasis (P=0.0001), and recurrence (P=0.01) were the factors affecting the overall survival of osteosarcoma patients. Ezrin and HER2/neu are overexpressed and coexpressed in osteosarcoma with adverse prognostic features such as high grade. Membranous pattern of HER2/neu seems to be more important than the cytoplasmic pattern because of its impact on metastasis-free and event-free survival. Therefore, ezrin and HER2/neu could be potential prognostic markers and treatment targets for osteosarcoma.

Amphiregulin enhances intercellular adhesion molecule-1 expression and promotes tumor metastasis in human osteosarcoma

Osteosarcoma is a common, high malignant, and metastatic bone cancer. Amphiregulin (AREG) has been associated with cancer cellular activities. However, the effect of AREG on metastasis activity in human osteosarcoma cells has yet to be determined. We determined that AREG increases the expression of intercellular adhesion molecule-1 (ICAM-1) through PI3K/Akt signaling pathway via its interaction with the epidermal growth factor receptor, thus resulting in the enhanced cell migration of osteosarcoma. Furthermore, AREG stimulation increased the association of NF-κB to ICAM-1 promoter which then up-regulated ICAM-1 expression. Finally, we observed that shRNA silencing of AREG decreased osteosarcoma metastasis in vivo. Our findings revealed a relationship between osteosarcoma metastatic potential and AREG expression and the modulating effect of AREG on ICAM-1 expression.

ZD6474, a new treatment strategy for human osteosarcoma, and its potential synergistic effect with celecoxib

ZD6474, a small molecule VEGFR and EGFR tyrosine kinase inhibitor, has been considered as a promising tumor-targeted drug in various malignancies. EGFR and cyclooxygenase-2 (COX-2) were found overexpressed in osteosarcoma in previous reports, so here we tried to explore the anti-osteosarcoma effect of ZD6474 alone or combination with celecoxib, a COX-2 inhibitor. The data demonstrated that ZD6474 inhibited the growth of osteosarcoma cells, and promoted G1-phase cell cycle arrest and apoptosis by inhibiting the activity of EGFR tyrosine kinase, and consequently suppressing its downstream PI3k/Akt and MAPK/ERK pathway. Additionally, daily administration of ZD6474 produced a dose-dependent inhibition of tumor growth in nude mice. Celecoxib also significantly inhibited the growth of osteosarcoma cells in dose-dependent manner, while combination of ZD6474 and celecoxib displayed a synergistic or additive antitumor effect on osteosarcoma in vitro and in vivo. The possible molecular mechanisms to address the synergism are likely that ZD6474 induces the down-regulation of COX-2 expression through inhibiting ERK phosphorylation, while celecoxib promotes ZD6474-directed inhibition of ERK phosphorylation. In conclusion, ZD6474 exerts direct anti-proliferative effects on osteosarcoma cells, and the synergistic antitumor effect of the combination of ZD6474 with celecoxib may indicate a new strategy of the combinative treatment of human osteosarcoma.

Prognostic significance and frequency of EGFR expression and amplification in surgically resected advanced gastric cancer

OBJECTIVE

The aim of this study is to find the frequency and the role of epidermal growth factor receptor expression as a prognostic biomarker in gastric cancer.

METHODS

We evaluated the prognostic value and frequency of epidermal growth factor receptor expression and amplification using immunohistochemistry and silver in situ hybridization in a large cohort of curatively resected gastric cancer.

RESULTS

Of the total of 935 cases, 294 (31.4%), 101 (10.8%) and 36 (3.9%) patients showed epidermal growth factor receptor 1+, 2+ and 3+ expression on immunohistochemistry, respectively. Epidermal growth factor receptor-positive (2+/3+) patients more frequently had intestinal type than epidermal growth factor receptor-negative (0/1+) patients (82.5 vs. 44.1%, P < 0.001). After adjusting for sex, age, stage and adjuvant chemotherapy, epidermal growth factor receptor-positive patients had a favorable overall survival outcome compared with epidermal growth factor receptor-negative patients (hazard ratio, 0.734; 95% confidence interval, 0.541-0.997; P = 0.047), especially in Stage III disease (hazard ratio, 0.676; 95% confidence interval, 0.472-0.968; P = 0.033). Among the 393 cases available for  in situ hybridization, the correlation between immunohistochemistry and in situ hybridization was statistically significant (P = 0.001). Thirteen patients with gene amplification (3.3%) did not show different survival outcome with others (P = 0.359).

CONCLUSION

Epidermal growth factor receptor positivity was an independent favorable prognostic factor for gastric cancer, especially in Stage III disease.

EGFR is not a major driver for osteosarcoma cell growth in vitro but contributes to starvation and chemotherapy resistance

Background

Enhanced signalling via the epidermal growth factor receptor (EGFR) is a hallmark of multiple human carcinomas. However, in recent years data have accumulated that EGFR might also be hyperactivated in human sarcomas. Aim of this study was to investigate the influence of EGFR inhibition on cell viability and its interaction with chemotherapy response in osteosarcoma cell lines.

Methods

We have investigated a panel of human osteosarcoma cell lines regarding EGFR expression and downstream signalling. To test its potential applicability as therapeutic target, inhibition of EGFR by gefitinib was combined with osteosarcoma chemotherapeutics and cell viability, migration, and cell death assays were performed.

Results

Osteosarcoma cells expressed distinctly differing levels of functional EGFR reaching in some cases high amounts. Functionality of EGFR in osteosarcoma cells was proven by EGF-mediated activation of both MAPK and PI3K/AKT pathway (determined by phosphorylation of ERK1/2, AKT, S6, and GSK3β). The EGFR-specific inhibitor gefitinib blocked EGF-mediated downstream signal activation. At standard in vitro culture conditions, clinically achievable gefitinib doses demonstrated only limited cytotoxic activity, however, significantly reduced long-term colony formation and cell migration. In contrast, under serum-starvation conditions active gefitinib doses were distinctly reduced while EGF promoted starvation survival. Importantly, gefitinib significantly supported the anti-osteosarcoma activities of doxorubicin and methotrexate regarding cell survival and migratory potential.

Conclusion

Our data suggest that EGFR is not a major driver for osteosarcoma cell growth but contributes to starvation- and chemotherapy-induced stress survival. Consequently, combination approaches including EGFR inhibitors should be evaluated for treatment of high-grade osteosarcoma patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0251-5) contains supplementary material, which is available to authorized users.

ErbB receptors as prognostic and therapeutic drug targets in bone and soft tissue sarcomas

ErbB receptors have been intensely studied to understand their importance in cancer biology and as therapeutic targets, and many ErbB inhibitors are now used in the clinical setting. A large number of studies have been conducted to examine the expression of ErbB family members in bone and soft tissue sarcomas, including osteosarcomas, synovial sarcomas, Ewing sarcomas, rhabdomyosarcomas, and so on. Nevertheless, the clinical implications of ErbB receptors remain elusive. To illustrate the potential of ErbB family members as prognostic and therapeutic drug targets in bone and soft tissue sarcomas, we summarized the molecular evidence and observations from clinical and basic trials.

Oscillating magnet array-based nanomagnetic gene transfection of human mesenchymal stem cells

Aim: In this work, the potential of nanomagnetic transfection of primary human mesenchymal stem cells (hMSCs) and the effects of a novel nonviral oscillating magnet array system in enhancing transfection efficiency were investigated. Materials & methods: Green fluorescent protein plasmids coupled to magnetic nanoparticles (MNPs) were introduced onto hMSCs in culture. Magnetic fields generated by arrays of neodymium iron boron magnets positioned below the culture plates direct the MNP/DNA complexes into contact with the cells. The magnet arrays were oscillated, promoting more efficient endocytosis via mechanical stimulation. Green fluorescent protein expression, cell viability and stem cell surface markers were assayed. Results: MNP/DNA complexes were delivered into hMSCs, and the oscillating magnet array system appears to improve transfection efficiency as well as cell viability. The expression of hMSC-specific cell surface markers was unaffected. Conclusion: Nonviral transfection using MNPs and oscillating magnet arrays offers a more efficient and ‘cell-friendly’ method of transfecting hMSCs than other nonviral techniques, while preserving their stem cell characteristics.

Original submitted 8 March 2012; Revised submitted 12 February 2013

Targeting receptor tyrosine kinases in osteosarcoma and Ewing sarcoma: current hurdles and future perspectives

Osteosarcoma (OS) and Ewing sarcoma (ES) are the two most common types of primary bone cancer, which mainly affect children and young adults. Despite intensive multi-modal treatment, the survival of both OS and ES has not improved much during the last decades and new therapeutic options are awaited. One promising approach is the specific targeting of transmembrane receptor tyrosine kinases (RTKs) implicated in these types of bone cancer. However, despite encouraging in vitro and in vivo results, apart from intriguing results of Insulin-like Growth Factor-1 Receptor (IGF-1R) antibodies in ES, clinical studies are limited or disappointing. Primary resistance to RTK inhibitors is frequently observed in OS and ES patients, and even patients that initially respond well eventually develop acquired resistance. There are, however, a few remarks to make concerning the current set-up of clinical trials and about strategies to improve RTK-based treatments in OS and ES. This review provides an overview concerning current RTK-mediated therapies in OS and ES and discusses the problems observed in the clinic. More importantly, we describe several strategies to overcome resistance to RTK inhibitors which may significantly improve outcome of OS and ES patients.

Protein kinase C epsilon and genetic networks in osteosarcoma metastasis

Osteosarcoma (OS) is the most common primary malignant tumor of the bone, and pulmonary metastasis is the most frequent cause of OS mortality. The aim of this study was to discover and characterize genetic networks differentially expressed in metastatic OS. Expression profiling of OS tumors, and subsequent supervised network analysis, was performed to discover genetic networks differentially activated or organized in metastatic OS compared to localized OS. Broad trends among the profiles of metastatic tumors include aberrant activity of intracellular organization and translation networks, as well as disorganization of metabolic networks. The differentially activated PRKCε-RASGRP3-GNB2 network, which interacts with the disorganized DLG2 hub, was also found to be differentially expressed among OS cell lines with differing metastatic capacity in xenograft models. PRKCε transcript was more abundant in some metastatic OS tumors; however the difference was not significant overall. In functional studies, PRKCε was not found to be involved in migration of M132 OS cells, but its protein expression was induced in M112 OS cells following IGF-1 stimulation.

Nanomagnetic Gene Transfection for Non-Viral Gene Delivery in NIH 3T3 Mouse Embryonic Fibroblasts

The objective of this work was to examine the potential of oscillating nanomagnetic gene transfection systems (magnefect-nano™) for improving the transfection efficiency of NIH3T3 mouse embryonic fibroblasts (MEFs) in comparison to other non-viral transfection techniques-static magnetofection™ and the cationic lipid agent, Lipofectamine 2000™. Magnetic nanoparticles (MNPs) associated with the plasmid coding for green fluorescent protein (GFP) were used to transfect NIH3T3 cells. The magnefect-nano system was evaluated for transfection efficiency, and any potential associated effects on cell viability were investigated. MNPs associated with the plasmid coding for GFP were efficiently delivered into NIH3T3 cells, and the magnefect-nano system significantly enhanced overall transfection efficiency in comparison to lipid-mediated gene delivery. MNP dosage used in this work was not found to affect the cell viability and/or morphology of the cells. Non-viral transfection using MNPs and the magnefect-nano system can be used to transfect NIH3T3 cells and direct reporter gene delivery, highlighting the wide potential of nanomagnetic gene transfection in gene therapy.

Epidermal growth factor receptor: is it a feasible target for the treatment of osteosarcoma?

Purpose

Features of epidermal growth factor receptor (EGFR) expression in osteosarcoma and in vitro efficacies of EGFR inhibitors against osteosarcoma cells were evaluated.

Materials and Methods

Thirty biopsy samples of osteosarcoma patients were retrospectively analyzed for EGFR protein expression by immunohistochemistry. Relationships between EGFR expression and clinicopathologic characteristics and treatment outcomes were evaluated. Four osteosarcoma cell lines were analyzed for EGFR and p-EGFR expression by western blotting. Efficacies of gefitinib and BIBW2992 on osteosarcoma cells were evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Tyrosine kinase domains in exons 18 to 21 were sequenced and gene expression analyses of EGFR and PTEN were performed in four osteosarcoma cell lines.

Results

EGFR protein was expressed in 27 (90%) samples (6 low, 12 intermediate, 9 high) and in three cell lines. Intermediate or high staining for EGFR was related to a tumor volume<150 mL (p<0.001) and histologic subtype other than osteoblastic type (p=0.03). However, EGFR expression was not associated with histologic response to preoperative chemotherapy or survival. Gefitinib and BIBW 2992 did not have any significant inhibitory effect on cell viabilities. DNA sequencing analysis revealed three osteosarcoma cell lines have single base changes at codon 2361 of exon 20 (G to A), without affecting translation results. Furthermore, no mutation was found to be associated with constitutive EGFR activation.

Conclusion

In the present study, gefitinib and BIBW2992 were not effective against osteosarcoma cells. However, as osteosarcoma cells express EGFR, further studies are necessary to explore the potential of other therapeutic agents targeting EGFR.

Expression of epidermal growth factor receptor in canine osteosarcoma: association with clinicopathological parameters and prognosis

Expression of epidermal growth factor receptor (EGFR) is associated with aggressive growth and metastasis of a range of tumours, including osteosarcomas (OS), although some studies have reported no relevance to clinicopathological events or prognosis. The present study evaluated EGFR mRNA and protein expression in a panel of OS cell lines, normal bones, frozen primary OS and tissue microarrays. EGFR expression was significantly elevated in primary OS compared to normal bones and in metastases of OS to the lungs in comparison with extrapulmonary sites. However, there were no clinical or pathological associations with mRNA expression levels in frozen tumours. Tissue microarray analysis demonstrated that a subset of canine OS with high EGFR expression was associated with significantly shorter survival times and disease-free intervals. Cytoplasmic expression of EGFR was present in 75% of metastases and was similar to expression in primary tumours. EGFR expression alone is not a reliable predictor of outcome and other markers are necessary for further prognostic stratification of dogs with OS. However, these findings suggest that a subset of dogs may benefit from anti-EGFR adjuvant therapies.

Epidermal growth factor receptor signalling contributes to osteoblastic stromal cell proliferation, osteoclastogenesis and disease progression in giant cell tumour of bone

AIMS

Epidermal growth factor receptor (EGFR) is implicated in bone remodelling. The aim was to determine whether EGFR protein expression contributes to the aggressiveness and recurrence potential of giant cell tumour of bone (GCTB), an osteolytic primary bone tumour that can exhibit markedly variable clinical behaviour.

METHODS AND RESULTS

Immunohistochemical analysis on tissue microarrays (TMA) of 231 primary, 97 recurrent, 17 metastatic and 26 malignant GCTBs was performed using TMA analysis software and whole digital slides allowing validated scoring. EGFR expression was restricted to neoplastic stromal cells and was significantly more frequent in recurrent (71 of 92; 77%) than in non-recurrent GCTBs (86 of 162; 53%) (P = 0.002); and in clinicoradiologically aggressive (31 of 43; 72%) than latent (27 of 54; 50%) cases (P = 0.034). Detecting phosphotyrosine epitopes pY1068 and -pY1173 indicated active EGFR signalling, and finding EGFR ligands EGF and transforming growth factor-α restricted to cells of the monocytic lineage suggested paracrine EGFR activation in stromal cells. In functional studies EGF supported proliferation of GCTB stromal cells, and the addition of EGF and macrophage-colony stimulating factor promoted osteoclastogenesis.

CONCLUSION

In GCTB, EGFR signalling in neoplastic stromal cells may contribute to disease progression through promoting stromal cell proliferation and osteoclastogenesis.

Met interacts with EGFR and Ron in canine osteosarcoma

The receptor tyrosine kinase (RTK) Met is known to be over-expressed in canine osteosarcoma (OSA). In human cancers, the RTKs Met, epidermal growth factor receptor (EGFR) and Ron are frequently co-expressed and engage in heterodimerization, altering signal transduction and promoting resistance to targeted therapeutics. We found that EGFR and Ron are expressed in canine OSA cell lines and primary tissues, EGFR and Ron are frequently phosphorylated in OSA tumour samples, and Met is co-associated with EGFR and Ron in canine OSA cell lines. Transforming growth factor alpha (TGFα) and hepatocyte growth factor (HGF) stimulation induced amplification of ERK1/2 and STAT3 phosphorylation in OSA cells and Met was phosphorylated following TGFα stimulation providing evidence for receptor cross-talk. Lastly, treatment of OSA cells with combined gefitinib and crizotinib inhibited cell proliferation in an additive manner. Together, these data support the notion that Met, EGFR and Ron interact in OSA cells and as such, may represent viable targets for therapeutic intervention.

High-throughput genotyping in osteosarcoma identifies multiple mutations in phosphoinositide-3-kinase and other oncogenes

BACKGROUND

The identification of new genes that are mutated in osteosarcomas is critical to developing a better understanding of the molecular pathogenesis of this disease and discovering new targets for therapeutic development.

METHODS

The authors identified somatic nonsynonymous coding mutations in oncogenes associated with human cancers and hotspot mutations from tumor suppressor genes that were either well described in the literature or observed multiple times in human cancer sequencing efforts. Then, 961 mutations in 89 genes were systematically characterized across 98 osteosarcoma tumor samples and cell lines. All identified mutations were replicated on an independent platform using homogeneous mass extend matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

In total, 14 mutations were identified in at least 1 osteosarcoma tumor sample or cell line. Some of the genetic changes identified were in tumor suppressor genes previously identified as altered in osteosarcoma: p53 (arginine→histidine at codon 273 [R273H], R→cysteine at codon 723 [R273C], and tyrosine→C at codon 163 [Y163C]) and retinoblastoma 1 (RB1) (glutamic acid→* at codon 137 [E137*]). Notably, multiple mutations were identified in phosphoinositide-3-kinase (PI3K), catalytic, alpha polypeptide (PIK3CA) (H1047R, E→lysine at codon 545 [E545K], and H→proline at codon 701 [H701P]) that were not observed previously in osteosarcoma. In addition, mutations in v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) (glycine→serine at codon 12 [G12S]); cubilin (CUBN) (isolucine→valine at codon 3189 [I3189V]; observed in 2 separate tumor samples); cadherin 1, type 1, epithelial (CDH1) (alanine→threonine at codon 617 [A617T]; observed in 2 separate tumor samples); catenin (cadherin-associated protein), beta 1, 88 kDa (CTNNB1) (asparagine→S at codon 287 [N287S]); and fibrous sheath CABYR binding protein (FSCB) (S→leucine at codon 775 [S775L]) were observed.

CONCLUSIONS

In this largest mutational profiling of osteosarcoma to date, the authors identified for the first time several mutations involving the PI3K pathway, adding osteosarcoma to the growing list of malignancies with PI3K mutations. In addition, they initiated a mutational map detailing DNA sequence changes across a variety of osteosarcoma subtypes and offered new candidates for therapeutic targeting.

Copy number gains in EGFR and copy number losses in PTEN are common events in osteosarcoma tumors

BACKGROUND

Osteosarcoma cell lines and tumors have been shown to express epidermal growth factor receptor (EGFR) and harbor amplifications at the EGFR locus. In this study, the authors further analyzed the genomic features of EGFR in osteosarcoma tumors and investigated whether they correlate with phosphatase and tensin homolog (PTEN) expression and copy number status.

METHODS

EGFR and PTEN expression was assessed by immunohistochemistry (n = 28), and copy number alterations at the EGFR and PTEN loci were surveyed using Affymetrix (Santa Clara, Calif) 50K single nucleotide polymorphism (SNP) arrays (n = 31) and fluorescence in situ hybridization (FISH) (n = 27). The EGFR tyrosine kinase domain was sequenced to survey for activating mutations (n = 34). In addition, EGFRvIII expression was assessed using reverse transcriptase polymerase chain reaction (n = 24). Results were correlated with available clinical information on 59 patients, with a median age of 14.1 years (range, 5-23 years) and median follow-up of 4.4 years.

RESULTS

EGFR expression was detected in the majority of osteosarcoma tumors surveyed (23 of 28; 82%). SNP arrays revealed evidence of frequent copy number gains at 7p11.2 and losses at 10q23.21. A sizeable subset (16 of 27 cases; 59%) showed gains at the EGFR locus using FISH (amplification in 4 of 27 [15%] and balanced chromosome 7 polysomy in 12 of 27 [44%]), and 12 cases showed deletions at the PTEN locus (biallelic deletions in 4 of 27 [15%] and monoallelic deletion in 9 of 27 [33%]). No activating mutations in the EGFR tyrosine kinase domain, EGFRvIII expression, or association with clinical findings were detected.

CONCLUSIONS

EGFR expression and genomic gains at the EGFR locus are prevalent in osteosarcoma tumors, which also commonly harbor deletions at the PTEN locus.

Biological importance of a polymorphic CA sequence within intron 1 of the epidermal growth factor receptor gene (EGFR) in high grade central osteosarcomas

Expression of EGFR in high grade osteosarcomas has been observed to be correlated with an improved prognosis. Yet, the underlying mechanism remained unclear since amplifications of EGFR have rarely been described. Recently, the length of a polymorphic CA repeat located at a 5'-regulatory sequence in the intron 1 of the EGFR gene (SSR I) has been shown to be associated with its basal transcriptional activity. We therefore determined the allelic length of CA SSR-I in 219 cases of high grade osteosarcoma and correlated the results with EGFR expression in 34 cases, the presence of amplifications within the CA SSR-I repeat in 59 cases, and clinical follow-up. Our results confirm that in osteosarcoma patients short alleles are more frequent than longer ones, 16 CA repeats being the most frequent. The allele composition differed significantly from the one recently described in a healthy control population (P < 0.01). Short alleles tended to be associated with increased expression of EGFR. Amplifications of the EGFR gene were seen in 13.5% of cases. Significant correlations between allele length composition and neoadjuvant chemotherapy response or long term clinical outcome could not be established. While we were able to show that high frequency of EGFR expression in osteosarcomas is associated with predominantly short alleles of EGFR-CA SSR I, persisting shortcomings in the correspondence with clinical data point toward the existence of additional, putatively more important transcription control mechanisms for EGFR in osteosarcomas which might account for the good prognostic value of EGFR expression.