Establishment, characterization, and genetic profiling of patient-derived osteosarcoma cells from a patient with retinoblastoma

Osteosarcoma is the most common malignant bone cancer in pediatric patients. Patients who respond poorly to chemotherapy experience worse clinical outcomes with a high mortality rate. The major challenge is the lack of effective drugs for these patients. To introduce new drugs for clinical approval, preclinical studies based on in vitro models must demonstrate the potency of the tested drugs, enabling the drugs to enter phase 1 clinical trials. Patient-derived cell culture is a promising testing platform for in vitro studies, as they more accurately recapitulate cancer states and genetic profiles compared to cell lines. In the present study, we established patient-derived osteosarcoma cells (PDC) from a patient who had previously been diagnosed with retinoblastoma. We identified a new variant of a germline mutation in the RB1 gene in the tissue of the patient. The biological effects of this PDC were studied to observe whether the cryopreserved PDC retained a feature of fresh PDC. The cryopreserved PDC preserved the key biological effects, including cell growth, invasive capability, migration, and mineralization, that define the conserved phenotypes compared to fresh PDC. From whole genome sequencing analysis of osteosarcoma tissue and patient-derived cells, we found that cryopreserved PDC was a minor population in the origin tissue and was selectively grown under the culture conditions. The cryopreserved PDC has a high resistance to conventional chemotherapy. This study demonstrated that the established cryopreserved PDC has the aggressive characteristics of osteosarcoma, in particular the chemoresistance phenotype that might be used for further investigation in the chemoresistant mechanism of osteosarcoma. In conclusion, the approach we applied for primary cell culture might be a promising method to generate in vitro models for functional testing of osteosarcoma.

Combinatorial Gene Expression Profiling of Serum HULC, HOTAIR, and UCA1 lncRNAs to Differentiate Hepatocellular Carcinoma from Liver Diseases: A Systematic Review and Meta-Analysis

Hepatocellular carcinoma (HCC) presents a significant global health challenge due to limited early detection methods, primarily relying on conventional approaches like imaging and alpha-fetoprotein (AFP). Although non-coding RNAs (ncRNAs) show promise as potential biomarkers in HCC, their true utility remains uncertain. We conducted a comprehensive review of 76 articles, analyzing 88 circulating lncRNAs in 6426 HCC patients. However, the lack of a standardized workflow protocol has hampered holistic comparisons across the literature. Consequently, we herein confined our meta-analysis to only a subset of these lncRNAs. The combined analysis of serum highly upregulated in liver cancer (HULC) gene expression with homeobox transcript antisense intergenic RNA (HOTAIR) and urothelial carcinoma-associated 1 (UCA1) demonstrated markedly enhanced sensitivity and specificity in diagnostic capability compared to traditional biomarkers or other ncRNAs. These findings could have substantial implications for the early diagnosis and tailored treatment of HCC.

Deciphering the Biology of Circulating Tumor Cells through Single-Cell RNA Sequencing: Implications for Precision Medicine in Cancer

Circulating tumor cells (CTCs) hold unique biological characteristics that directly involve them in hematogenous dissemination. Studying CTCs systematically is technically challenging due to their extreme rarity and heterogeneity and the lack of specific markers to specify metastasis-initiating CTCs. With cutting-edge technology, single-cell RNA sequencing (scRNA-seq) provides insights into the biology of metastatic processes driven by CTCs. Transcriptomics analysis of single CTCs can decipher tumor heterogeneity and phenotypic plasticity for exploring promising novel therapeutic targets. The integrated approach provides a perspective on the mechanisms underlying tumor development and interrogates CTCs interactions with other blood cell types, particularly those of the immune system. This review aims to comprehensively describe the current study on CTC transcriptomic analysis through scRNA-seq technology. We emphasize the workflow for scRNA-seq analysis of CTCs, including enrichment, single cell isolation, and bioinformatic tools applied for this purpose. Furthermore, we elucidated the translational knowledge from the transcriptomic profile of individual CTCs and the biology of cancer metastasis for developing effective therapeutics through targeting key pathways in CTCs.

Potential target identification for osteosarcoma treatment: Gene expression re-analysis and drug repurposing

Survival rate of osteosarcoma has remained plateaued for the past three decades. New treatment is needed to improve survival rate. Drug repurposing, a method to identify new indications of previous drugs, which saves time and cost compared to the de novo drug discovery. Data mining from gene expression profile was carried out and new potential targets were identified by using drug repurposing strategy. Selected data were newly categorized as pathophysiology and metastasis groups. Data were normalized and calculated the differential gene expression. Genes with log fold change ≥ 2 and adjusted p-value ≤ 0.05 were selected as primary candidate genes (PCGs). PCGs were further enriched to determine the secondary candidate genes (SCGs) by protein interaction analysis, upstream transcription factor and related-protein kinase identification. PCGs and SCGs were further matched with gene targeted of corresponding drugs from the Drug Repurposing Hub. A total of 778 targets were identified (360 from PCGs, and 418 from SCGs). This newly identified KLHL13 is a new candidate target based on its molecular function. KLHL13 was upregulated in clinical samples. We found 256 drugs from matching processes (50anti-cancerand206non-anticancerdrugs). Clinical trials of anti-cancer drugs from 5 targets (CDK4, BCL-2, JUN, SRC, PIK3CA) are being performed for osteosarcoma treatment. Niclosamide and synthetic PPARɣ ligands are candidates for repurposing due to the possibility based on their mechanism and pharmacology properties. Re-analysis of gene expression profile could identify new potential targets, confirm a current implication, and expand the chance of repurposing drugs for osteosarcoma treatment.

Genomics-Driven Precision Medicine in Pediatric Solid Tumors

Over the past decades, several study programs have conducted genetic testing in cancer patients to identify potential genetic targets for the development of precision therapeutic strategies. These biomarker-driven trials have demonstrated improved clinical outcomes and progression-free survival rates in various types of cancers, especially for adult malignancies. However, similar progress in pediatric cancers has been slow due to their distinguished mutation profiles compared to adults and the low frequency of recurrent genomic alterations. Recently, increased efforts to develop precision medicine for childhood malignancies have led to the identification of genomic alterations and transcriptomic profiles of pediatric patients which presents promising opportunities to study rare and difficult-to-access neoplasms. This review summarizes the current state of known and potential genetic markers for pediatric solid tumors and provides perspectives on precise therapeutic strategies that warrant further investigations.

Characterization of Cell-free DNA Size Distribution in Osteosarcoma Patients

PURPOSE

Cell-free DNA analysis is a powerful tool for non-invasively predicting patient outcomes. We analyzed the size distribution of cfDNA and assessed its prognostic and diagnostic values in an osteosarcoma cohort.

EXPERIMENTAL DESIGN

The fragment size distribution and level of cfDNA were analyzed in 15 healthy donors and 50 osteosarcoma patients using automated capillary electrophoresis. The prognostic performance of cfDNA size analysis was assessed using univariate and multivariable analyses. By performing whole-genome sequencing of matched cfDNA and osteosarcoma tissue samples, we investigated the correlation between the size and mutation profiles of cfDNA and the mutation concordance between cfDNA and paired tissue tumors.

RESULTS

The size of cfDNA fragments in osteosarcoma patients was significantly shorter than in healthy donors, with the integrative analysis of size distribution and level of cfDNA achieving a high specificity and sensitivity of 100%. The short cfDNA fragment (150 bp cut-off) was an independent prognostic predictor in this osteosarcoma cohort [HR=9.03; 95% CI=1.13-72.20); p=0.038]. Shortened cfDNA fragments were found to be a major source of mutations. Enrichment of cfDNA fragments with less than or equal to 150 bp by in-silico size selection remarkedly improved the detection of copy number variation (CNV) signals up to 2.3-fold when compared to total cfDNA, with a higher concordance rate with matched osteosarcoma tissue.

CONCLUSIONS

This finding demonstrated the potential of cfDNA size profiling in the stratification of poor prognostic patients with osteosarcoma. The short fragments of cfDNA are a promising source for boosting the detection of significant mutations in osteosarcoma.

Mass Spectrometric-Based Proteomics for Biomarker Discovery in Osteosarcoma: Current Status and Future Direction

Due to a lack of novel therapies and biomarkers, the clinical outcomes of osteosarcoma patients have not significantly improved for decades. The advancement of mass spectrometry (MS), peptide quantification, and downstream pathway analysis enables the investigation of protein profiles across a wide range of input materials, from cell culture to long-term archived clinical specimens. This can provide insight into osteosarcoma biology and identify candidate biomarkers for diagnosis, prognosis, and stratification of chemotherapy response. In this review, we provide an overview of proteomics studies of osteosarcoma, indicate potential biomarkers that might be promising therapeutic targets, and discuss the challenges and opportunities of mass spectrometric-based proteomics in future osteosarcoma research.

Descriptive epidemiology of soft tissue sarcomas and gastrointestinal stromal tumors in Thailand

This study aimed to analyze burden of STS and GIST in population and survival rate which represented the current situation of treatment in Thailand. The data was collected from five population-based cancer registries around the country for the period 2001 through 2015. The Segi world standard population was used to calculated age-standardized incidence rates (ASR). Standardized rate ratios (SRR) were used to compare populations. Joinpoint Trend Analysis was used to assess changes in incidence. STATA was used to examine patient survival rates. During the study period, 4080 cases of STS and 457 cases of GIST were reported. The ASR of STS and GIST was 2.14/100,000 person-years and 0.22/100,000 person-years, respectively. The most common histological types of STS were unspecified sarcoma (24.8%), leiomyosarcoma (19.0%) and liposarcoma (11.4%). The overall ASR of STS in Thailand was relatively low compared to Western countries. The five-year survival rate was 62.6% for STS and 63.4% for GIST, which was comparable to the rates reported in other countries. This is the first report of STS and GIST from PBCRs in Thailand. Based on current healthcare service, an overall survival rates of STS and GIST are comparable to those reported from others.

Osteosarcoma-Specific Genes as a Diagnostic Tool and Clinical Predictor of Tumor Progression

Simple Summary

The standard method for the diagnosis and monitoring of osteosarcoma is biopsy and tumor imaging, which causes discomfort to patients and is difficult to repeat. A blood sample can be used as a non-invasive method for monitoring tumor material. Vimentin and ezrin show clinical significance in samples obtained from OS patients but need circulating tumor cell purification, since they are expressed in leukocytes. Due to the low-temperature storage of the samples, it proved impossible to perform purification to remove the contamination. We propose that novel or OS-specific biomarkers using differential gene expression from the Gene Expression Omnibus (GEO) database is a promising approach for developing diagnostic and tumor progression strategies. Seven genes from the database showed significant expression in OS cell lines/primary cells compared to a normal blood donor, together with ezrin and VIM. The expression of the five candidate genes together with ezrin and vimentin were quantified by qRT-PCR and analyzed using a mathematical model with high efficiency to discriminate between OS patients and normal samples, resulting in the selection of three candidate genes: COL5A2 (one of the five from the database) as well as ezrin and VIM. Our study demonstrates that these genes in retrospective samples could serve as tools of OS detection and predictors of disease progression.

Abstract

A liquid biopsy is currently an interesting tool for measuring tumor material with the advantage of being non-invasive. The overexpression of vimentin and ezrin genes was associated with epithelial-mesenchymal transition (EMT), a key process in metastasis and progression in osteosarcoma (OS). In this study, we identified other OS-specific genes by calculating differential gene expression using the Gene Expression Omnibus (GEO) database, confirmed by using quantitative reverse transcription-PCR (qRT-PCR) to detect OS-specific genes, including VIM and ezrin in the buffy coat, which were obtained from the whole blood of OS patients and healthy donors. Furthermore, the diagnostic model for OS detection was generated by utilizing binary logistic regression with a multivariable fractional polynomial (MFP) algorithm. The model incorporating VIM, ezrin, and COL5A2 genes exhibited outstanding discriminative ability, as determined by the receiver operating characteristic curve (AUC = 0.9805, 95% CI 0.9603, 1.000). At the probability cut-off value of 0.3366, the sensitivity and the specificity of the model for detecting OS were 98.63% (95% CI 90.5, 99.7) and 94.94% (95% CI 87.5, 98.6), respectively. Bioinformatic analysis and qRT-PCR, in our study, identified three candidate genes that are potential diagnostic and prognostic genes for OS.

An analysis of the incidence and survival rates of bone sarcoma patients in thailand: reports from population-based cancer registries 2001-2015

BACKGROUND

Epidemiology data from population-based cancer registries (PBCR) can be very valuable in the development of health policy and for improving the quality of cancer control strategies.

METHODS

This study analyzed the incidence of bone sarcomas in Thailand during 2001 - 2015 by analyzing data obtained from 5 PBCRs across country. Incidence rates per million person-years by sex, histological subtype, primary site and 5-year age group were calculated. Age-standardized incidence rates (ASR) were adjusted using the WHO's World Standard Population and comparisons between populations were done using standardized rate ratios (SRR). Incidence trends were evaluated using Joinpoint Trend Analysis. Survival rates were analyzed using STATA.

RESULTS

The ASR of bone sarcomas in Thailand was 5.1/10⁶ person-years, with an estimated 328 newly diagnosed bone sarcomas per year for the country overall. Osteosarcoma (52.5%), chondrosarcoma (18%), Ewing's sarcoma (11.6%), giant cell tumor (4.8%) and chordoma (4.7%) were the most common malignant bone tumors, representing 91.5% of all bone sarcomas. Bone sarcoma has a predilection for males (1.29:1) and an age-specific bimodal rate pattern closely related to the major histological subtypes, osteosarcoma. One- and five-year survival rates of Thai patients with bone sarcoma were 74% and 52%, respectively. Survival rates of bone sarcomas, particularly osteosarcoma, were lower than the rates reported from the United States, Europe and Japan.

CONCLUSION

The lower overall survival rate of bone sarcoma represented the gap of bone sarcoma control program in Thailand. That indicates the need for improvement in health promotion, treatment process and chemotherapy for bone sarcoma patients in the future.

Size distribution of cell-free DNA in oncology

Tumor-specific, circulating cell-free DNA (cfDNA) in liquid biopsy test is a novel promising biomarker in the advancement of cancer management, including early diagnosis, screening, prognosis, identification of actionable targets, and serial tumor monitoring. The specific size pattern of DNA fragments derived from cancer cells is observed to differ from that of cfDNA fragments shed by non-cancer cells. Research into the physiological and biological properties of cfDNA reveals the molecular signature carried by each cfDNA fragments, which can reflect their tissue origins, as well as the mutational profiles with significant genetic alterations. Understanding the fragmentation and size distribution of cfDNA might be a valuable hotspot in liquid biopsy research, with the potential to drive innovation in oncology.

Relationship Between O-GlcNAcase Expression and Prognosis of Patients With Osteosarcoma

Several studies have demonstrated a role of O-GlcNAcylation (O-GlcNAc) in tumorigenesis of various carcinomas by modification of tumor-associated proteins. However, its implication in the pathogenesis of osteosarcoma remains unclear. This study aimed to investigate the levels of O-GlcNAc and the expressions of O-linked N-acetylglucosamine transferase (OGT) and O-GlcNAcase (OGA) in human osteosarcoma tissues, by using immunohistochemistry; and to find correlations between the levels or expressions and several clinicopathologic parameters. There were 109 first diagnosed osteosarcoma patients, including Enneking stage IIB (n=70) and III (n=39). Correlations between the immunoreactive score (IRS) and clinicopathologic parameters, overall survival, and metastasis-free survival were evaluated. A positive correlation was found between the IRS of OGA and the percentage of postchemotherapeutic tumor necrosis (r=0.308; P=0.017). Univariate analysis revealed significantly lower OGA IRS in metastatic patients (P=0.020) and poor chemotherapeutic-responder patients (P=0.001). By multivariate analysis, presence of tumor metastasis (P=0.002) and lower OGA IRS (P=0.004) was significantly associated with shorter overall survival. Subgroup analysis in stage IIB osteosarcoma (n=70) demonstrated that male sex (P=0.019), presence of tumor recurrence (P=0.026), poor chemotherapeutic responder (P=0.022), and lower OGA IRS (P=0.019) were significantly correlated with short metastasis-free survival. But, lower OGA IRS was the only independent predictor for short metastasis-free survival (P=0.006). Our findings suggested that O-GlcNAc pathway, especially OGA, may involve in pathogenesis and aggressiveness of osteosarcoma. Low level of OGA expression may be used as a poor prognostic indicator.

Aberrant RL2 O-GlcNAc antibody reactivity against serum-IgA1 of patients with colorectal cancer

O-GlcNAcylation, a single attachment of N-acetylglucosamine (GlcNAc) on serine and threonine residues, plays important roles in normal and pathobiological states of many diseases. Aberrant expression of O-GlcNAc modification was found in many types of cancer including colorectal cancer (CRC). This modification mainly occurs in nuclear-cytoplasmic proteins; however, it can exist in some extracellular and secretory proteins. In this study, we investigated whether O-GlcNAc-modified proteins are present in serum of patients with CRC. Serum glycoproteins of CRC patients and healthy controls were enriched by wheat germ agglutinin, a glycan binding protein specifically binds to terminal GlcNAc and sialic acid. Two-dimensional gel electrophoresis, RL2 O-GlcNAc immunoblotting, affinity purification, and mass spectrometry were performed. The results showed that RL2 O-GlcNAc antibody predominantly reacted against serum immunoglobulin A1 (IgA1). The levels of RL2-reacted IgA were significantly increased while total IgA were not different in patients with CRC compared to those of healthy controls. Analyses by ion trap mass spectrometry using collision-induced dissociation and electron-transfer dissociation modes revealed one O-linked N-acetylhexosamine modification site at Ser₂₆₈ located in the heavy constant region of IgA1; unfortunately, it cannot be discriminated whether it was N-acetylglucosamine or N-acetylgalactosamine because of their identical molecular mass. Although failed to demonstrate unequivocally it was O-GlcNAc, these data indicated that serum-IgA had an aberrantly increased reactivity against RL2 O-GlcNAc antibody in CRC patients. This specific glycosylated form of serum-IgA1 will expand the spectrum of aberrant glycosylation which provides valuable information to cancer glycobiology.

Expression profiling of DNA methyl transferase I (DNMT1) and efficacy of a DNA-hypomethylating agent (decitabine) in combination with chemotherapy in osteosarcoma

Background

Abnormality in the DNA methylation process is one of the hallmarks of cancer. Emerging evidence strongly supports the idea that defects in DNA methyl transferases (DNMTs) are involved in tumor development and progression. This alteration has major effects at the transcription level of various cancer-associated genes.

Methods

Expression profiles of DNMT1 were investigated in fresh frozen tissues, patient-derived cells, and formalin-fixed paraffin-embedded tissues using immunoblotting and immunohistochemistry analysis. We also examined an anti-tumor effect of single DNA-hypomethylating agent (decitabine) and a combination of decitabine and chemotherapy in osteosarcoma cell lines.

Results

The results showed an overexpression of DNMT1 in most cases compared to normal cells and tissue samples. DNMT1 was also expressed at the same levels in paired primary cells derived from biopsy and post-chemotherapy tissues. Expression patterns of DNMT1 were examined in 77 osteosarcoma patients of whom 82% had positive DNMT1 with an IRS score > 0. Most of the cases expressed low to moderate levels of DNMT1 (IRS range 1-8, median = 2.0). Furthermore, we found that a combination of decitabine and chemotherapy had a synergistic effect in most of the tested osteosarcoma cells at a low dose therapeutic range of decitabine.

Conclusions

Our study revealed DNMT1 expression patterns that indicated potential roles of DNMT1 in osteosarcoma transformation and progression. This finding also suggests the efficacy of a combination therapy of decitabine with chemotherapy for osteosarcoma treatment.

Therapeutic potential and molecular mechanisms of mycophenolic acid as an anticancer agent

Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil (MMF), an immunosuppressive drug approved for the prophylaxis of allograft rejection in transplant recipients. Recent advances in the role of the type II isoform of inosine-5'-monophosphate dehydrogenase (IMPDH2) in the tumorigenesis of various types of cancer have called for a second look of MPA, the first IMPDH2 inhibitor discovered a hundred years ago, to be repurposed as an anticancer agent. Over a half century, a number of in vitro and in vivo experiments have consistently shown anticancer activity of MPA against several cell lines obtained from different malignancies and murine models. However, a few clinical trials have been conducted to investigate its anticancer activity in humans, and most of which have shown unsatisfactory results. Understanding of available evidence and underlying mechanism of action is a key step to be done so as to facilitate further investigations of MPA to reach its full therapeutic potential as an anticancer agent. This article provides a comprehensive review of non-clinical and clinical evidence available to date, with the emphasis on the molecular mechanism of action in which MPA exerts its anticancer activities: induction of apoptosis, induction of cell cycle arrest, and alteration of tumor microenvironment. Future perspective for further development of MPA to be an anticancer agent is extensively discussed, with the aim of translating the anticancer property of MPA from bench to bedside.

Phase II, multi-center, open-label, single-arm clinical trial evaluating the efficacy and safety of Mycophenolate Mofetil in patients with high-grade locally advanced or metastatic osteosarcoma (ESMMO): rationale and design of the ESMMO trial

Background

Clinical outcomes of patients with osteosarcoma remain unsatisfactory, with little improvement in a 5-year overall survival over the past three decades. There is a substantial need for further research and development to identify and develop more efficacious agents/regimens in order to improve clinical outcomes of patients for whom the prognosis is unfavorable. Recently, mycophenolate mofetil, a prodrug of mycophenolic acid, has been found to have anticancer activity against osteosarcoma in both in vitro and animal experiments, so that further investigation in humans is warranted.

Methods

A total of 27 patients with high-grade locally advanced or metastatic osteosarcoma will be enrolled into this phase II, multi-center, open-label, single-arm, two-stage clinical trial. The main objectives of this study are to determine the efficacy and safety of mycophenolate mofetil in the patients. The primary endpoint is progression-free survival at 16 weeks; the secondary endpoints include progression-free survival, overall survival, overall response rate, safety parameters, pharmacokinetic parameters, biomarkers, pain score, and quality of life. Mycophenolate mofetil at the initial dose of 5 g/day or lower will be administered for 4 cycles (28 days/cycle) or until disease progression or unacceptable toxicity. The dose of mycophenolate mofetil may be reduced by 1–2 g/day or withheld for some Grade 3 or Grade 4 toxicities whenever clinically needed. The duration of study participation is approximately 4–5 months, with a minimum of 12 study visits. If mycophenolate mofetil proves beneficial to some patients, as evidenced by stable disease or partial response at 16 weeks, administration of mycophenolate mofetil will continue in the extension period.

Discussion

This trial is the first step in the translation of therapeutic potential of mycophenolate mofetil emerging from in vitro and animal studies into the clinical domain. It is designed to assess the efficacy and safety of mycophenolate mofetil in patients with high-grade locally advanced or metastatic osteosarcoma. The results will provide important information about whether or not mycophenolate mofetil is worth further development.

Trial registration

This trial was prospectively registered on Thai Clinical Trials Registry (registration number: TCTR20190701001). The posted information will be updated as needed to reflect protocol amendments and study progress.

Phosphoproteome Profiling of Isogenic Cancer Cell-Derived Exosome Reveals HSP90 as a Potential Marker for Human Cholangiocarcinoma

The northeastern region of Thailand is well known to have a high incidence and mortality of cholangiocarcinoma (CCA). Protein phosphorylation status has been reported to reflect a key determinant of cellular physiology, but identification of phosphoproteins can be a problem due to the presence of phosphatase. Exosomes are stable toward circulating proteases and other enzymes in human blood and can be recognized before the onset of cancer progression. Here an in vitro metastatic model of isogenic CCA cells is used to provide insight into the phosphorylation levels of exosomal proteins derived from highly invasive cells. Gel-based and gel-free proteomics approaches are used to reveal the proteins differentially phosphorylated in relation to tumor cell phenotypes. Forty-three phosphoproteins are identified with a significant change in phosphorylation level. Phos-tag western blotting and immunohistochemistry staining are then employed to validate the candidate phosphoproteins. Heat shock protein 90 is successfully confirmed as being differentially phosphorylated in relation to tumor malignancy. Importantly, the aberrant phosphorylation of exosomal proteins might serve as a promising tool for the development of a biomarker for metastatic CCA.

Endoplasmic reticulum protein 29 (ERp29) as a novel prognostic marker and tumor suppressor in osteosarcoma

Background

Diverse aberrancy in genetic background, protein profiling, and biological pathways have emerged as important factors hindering discovery of effective treatment of osteosarcoma. In a previous study, we used a proteomic approach to identify some osteosarcoma-related proteins by analysis of protein profiling in individual patients through primary cell culture. Endoplasmic reticulum protein 29 (ERp29) emerged as a protein of interest for further study since accumulating evidence suggests it has broad functions in tumorigenesis of different types of cancer. Importantly, until now no report on examination of the expression patterns of ERp29 in osteosarcoma has been published.

Methods

In this study, an expression of ERp29 was examined in patient-derived osteosarcoma cells (7 cases) and normal bone graft-derived osteoblasts (7 cases) using western blotting. Expression profile of ERp29 in 94 osteosarcoma cases was investigated using immunohistochemically stained on formalin-fixed paraffin-embedded biopsied tissue. An association with clinicopathologic parameters and the patient survival was evaluated. The doubling time of five osteosarcoma cells lines expressing different levels of ERp29 was determined by a cell number along the exponential phase of the growth curve.

Results

The results substantiate the outcome from the proteomic study in which ERp29 expression was significantly higher in primary osteosarcoma cells compared to osteoblastic cells. Immunohistochemical analysis found that expression of ERp29 was low in 79% of the cases (immunoreactive score (IRS) <6). A significant correlation was observed between expression of ERp29 and patient survival. Lower expression of ERp29 (IRS<6) was statistically significantly associated with shorter overall survival of the patients (P = 0.041). In addition, we found that osteosarcoma cells with low ERp29 expression had a higher growth rate compared with high-ERp29-expressing cells.

Conclusions

These findings suggest a tumor suppressive role of ERp29 in osteosarcoma. In addition, ERp29 might potentially be applied as a prognostic indicator in patients with osteosarcoma.

Protein profiling of osteosarcoma tissue and soft callus unveils activation of the unfolded protein response pathway

Oncogenic drivers of osteosarcoma remain controversial due to the complexity of the genomic background of the disease. There are limited novel therapeutic options, and the survival rate of patients with osteosarcoma has not improved in decades. Genomic instability leads to complexity in various pathways, which is potentially revealed at the protein level. Therefore, the present study aimed to identify the mechanisms involved in the oncogenesis of osteosarcoma using proteomics and bioinformatics tools. As clinical specimens from patients are the most relevant disease-related source, expression patterns of proteins in osteosarcoma tissues were compared with soft tissue callus from donors containing high numbers of osteoblastic cells. Two-dimensional electrophoresis and liquid chromatography-tandem mass spectrometry (LC-MS/MS) successfully identified 33 differentially expressed proteins in the osteosarcoma tissues compared with the soft tissue callus. Among these proteins, 29 proteins were significantly upregulated in osteosarcoma. A functionally grouped network of the overexpressed proteins, that was created using the ClueGo and CluePedia applications, demonstrated that the unfolded protein response (UPR) pathway was activated mainly through the activating transcription factor 6 arm in osteosarcoma. The results of proteomics analysis were confirmed by elevated expression of UPR-related chaperone proteins, including 78 kDa glucose-related protein (GRP78), endoplasmin, calreticulin and prelamin-A/C, in the patient-derived primary cells and osteosarcoma cell lines. Furthermore, the expression of GRP78, a master regulator of the UPR, was enhanced in the osteosarcoma tissues of patients that were resistant to double regimen of doxorubicin and a platinum-based drug. The findings of the present study suggest that targeting the UPR pathway may be promising for the treatment of osteosarcoma.

Surgical outcomes of extracorporeal irradiation and re-implantation in extremities for high grade osteosarcoma: A retrospective cohort study and a systematic review of the literature

•

Diaphyseal resection of ECIR showed the promising outcome in osteosarcoma.

•

Less complications and structural permanence are advantages of DI-ECIR.

•

Tumor recurrence is comparable with other surgical reconstructions.

Purpose

To assess the failure rate and mode failure of high-grade osteosarcoma patients who received extracorporeal irradiation and re-implantation (ECIR) in extremities.

Patients and Methods

For the cohort study, patients who had received ECIR at a single institution between January 1996 and December 2014 were retrospectively evaluated. Characteristics of failure and time to failure were recorded and analyzed. In addition, a systematically search of published literatures regarding the use of ECIR for osteosarcoma was conducted. Failure rates and modes of failure were determined from the pooled data.

Results

In the cohort study, the overall reconstruction failure was 46% (23 of 50 cases) of which 6% were due to mechanical failure, and 40% were due to non-mechanical failure. In the systematic review, 164 cases reached the criteria for analysis (50 diaphysis, 97 osteochondral of lower extremity, 6 knee resection, and 11 proximal humerus resection). Among those cases, overall failure rate was 29.9% (49 of 164 cases) of which 7.9% were due to mechanical failure, and 22.0% to non-mechanical failure. Diaphyseal resection with intercalary re-implantation had a significantly lower failure rate than osteochondral reconstruction of lower extremity (OR: 2.7, p < 0.02), and knee extra-articular resection osteochondral re-implantation (OR: 10.5, p < 0.01).

Conclusions

Diaphyseal resection and extracorporeal irradiation of intercalary re-implantation offer the most promising outcome among other type of reconstructions. Availability of graft, fewer structural complications, and biological permanence are advantages of this reconstruction method.

Oncogenic roles of serine-threonine kinase receptor-associated protein (STRAP) in osteosarcoma

PURPOSE

To validate the presence of serine-threonine kinase receptor-associated Protein (STRAP) in osteosarcoma tissue and to investigate the oncological role of STRAP in osteosarcoma.

METHODS

Expression of STRAP protein in osteosarcoma tissue compared to soft callus (hyperactive bone healing tissue) and in multiple cell lines was examined using western blot analysis. Effects of STRAP silencing on cell proliferation, invasion, migration and re-implantability in chick chorioallantoic membrane (CAM) were observed in osteosarcoma cell lines (MNNG-HOS, 143B, and U2OS).

RESULTS

The result demonstrated that STRAP was highly up-regulated in osteosarcoma tissues compared with the normal physiological bone healing tissue (soft callus). Expression level of STRAP was markedly high in osteosarcoma cell lines with aggressive phenotype. Upon STRAP silencing, invasion and migration, but not proliferative activity, were selectively modulated in high-expression-STRAP cell lines. In addition, STRAP silencing reduced the success rate of tumor implantation and growth of MNNG-HOS cells in CAM model.

CONCLUSIONS

Serine-threonine kinase receptor-associated protein is up-regulated during osteosarcoma progression. The presence of STRAP enhances osteosarcoma cell invasion, migration and re-implantation ability, factors which play a critical role in metastasis. Serine-threonine kinase receptor-associated protein and its related pathway are worthy for further exploration as a novel target for anti-metastasis agents.

Decreasing O-GlcNAcylation affects the malignant transformation of MCF-7 cells via Hsp27 expression and its O-GlcNAc modification

O-GlcNAcylation is a dynamic posttranslational modification of nucleoplasmic proteins. Previously, we reported that the O-GlcNAcylation level was increased in primary breast and colorectal cancer tissues. However, its precise roles in cancer development and progression are still largely unexplored. The aim of the present study was to investigate the roles of O-GlcNAcylation in the malignant transformation of cancer cell lines. O-GlcNAcylation level was examined in six cancer cell lines including breast (MCF-7 and MDA-MB-231), colorectal (SW480 and SW620), and liver (SK-Hep1 and HepG2). We found that the levels of O-GlcNAcylation and O-GlcNAc transferase (OGT), an O-GlcNAc catalyzing enzyme, were obviously increased in all cancerous cells, except SK-Hep1, when compared to normal cells. Reducing O-GlcNAcylation using RNA interference against OGT showed a marked reduction in OGT and O-GlcNAcylation levels. Surprisingly, siOGT had no effect on cell growth under conventional monolayer cultures. However, it inhibited anchorage-independent growth in soft agar cultures of all cancer cells, except SK-Hep1. Under anoikis resistance conditions performed by spheroid cultures, siOGT treatment decreased viability only in MCF-7, SW480, and SW620 cells. Among them, OGT knockdown in MCF-7 cells revealed a high inhibitory effect on colony and spheroid cultures. Using two-dimensional gel electrophoresis and mass spectrometric analysis, heat shock protein 27 (Hsp27) was found to be the highest upregulated protein upon OGT knockdown. Immunoblots revealed that the Hsp27 protein level was increased but its O-GlcNAc modification level was decreased in siOGT-treated cells. These changes were associated with the inhibition of MCF-7 cell transformation. Notably, double knockdown of OGT and Hsp27 showed a reversal in the inhibitory effect on colony and spheroid cultures. Collectively, these results indicate that O-GlcNAcylation is required for anoikis resistance and anchorage-independent growth of MCF-7 cells. Blocking this glycosylation by OGT knockdown may regulate both Hsp27 protein expression and its O-GlcNAc modification levels. This alteration may play vital roles in malignant transformation.

Prognostic score for life expectancy evaluation of lung cancer patients after bone metastasis

BACKGROUND

This study identifies the overall survival status of lung cancer patients with bone metastasis and metastasis patterns. Poor prognostic factors were identified to develop a scoring system for estimating survival period after bone metastasis.

METHODS

A retrospective cohort analysis was performed at Chiang Mai University for the period January 1, 2006 and December 31, 2013. Time-to-event analysis was performed to estimate survival rate. The primary end point was death related to lung cancer. Univariate and multivariate analysis of the prognostic variables was done using the Cox's regression model. The score was derived from the corresponding estimated regression coefficients of significantly poor prognostic factors.

RESULTS

A total of 505 lung cancer with bone metastasis patients were analyzed. Four hundred two cases (79.6%) were concurrent diagnosis and 103 (20.4%) were subsequent diagnosis. The median survival time of lung cancer after bone metastasis 148 days. Male gender and ECOG 3-4 were significant poor prognostic factors for lung cancer after bone metastasis, with hazard ratios of 1.42 (95% CI 1.17-1.73), and 1.30 (95% CI 1.06-1.60), respectively. Prognosis score was determined using the binary term present/not-present for those factors. The curve from prognostic score summations of 2, 1 and 0 presented a good discrimination of survival expectancy, showing an expected median survival time of approximately 109, 146, and 225 days, respectively.

CONCLUSIONS

Prognostic score is a clinically simple and easy method for estimating life expectancy and for guiding interventions in bone metastasis of lung cancer.

Safety and efficacy of intralesional steroid injection for aggressive fibromatosis

Background

Treatment of recurrent aggressive fibromatosis (AF) following surgical resection is a clinical challenge. Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to be an effective option for controlling the disease. However, long-term NSAID use can result in unfavorable complications. This study was a trial of the use of intralesional steroid injection (ILSI) including investigation of safety margins and clinical outcomes of high-dose steroids for local use treatment of AF.

Methods

A prospective cohort study was conducted to evaluate the safety and efficacy of particulate corticosteroids for AF. Intralesional steroid injections of Kanolone® guided by ultrasound were given monthly for three consecutive months with 1 mg/kg/episode (a total of 3 mg/kg). Patients were followed up monthly for 3 months at the time of each monthly injection and then for an additional 3 months after the last injection. Complications from the procedure and clinical outcomes were monitored.

Results

Eight recurrent AF patients completed the full 6-month evaluation process. No procedure-related complications were reported either during the injection period or the follow-up period. None of the patients developed Cushingoid features. The highest number of complication events, all of which were mild or detectable only by laboratory analysis, occurred during the month following the second injection. Triamcinolone levels were significantly increased 24 h after injection, and four of the eight cases developed hypothalamic-pituitary-axis suppression. Tumors were stabilized in 83.3% of the cases during the study period, and pain and functional ability scores improved significantly.

Conclusions

Intralesional steroid injection appears to be a safe and effective alternative treatment for recurrent AF.

Trial registration

TCTR20150409001; Registered date: 9 April 2015; The safety and result of intratumoral steroid injection for aggressive fibromatosis.

Electronic supplementary material

The online version of this article (10.1186/s12957-017-1262-9) contains supplementary material, which is available to authorized users.

Activation Status of Receptor Tyrosine Kinases as an Early Predictive Marker of Response to Chemotherapy in Osteosarcoma

Receptor tyrosine kinases (RTKs) are membrane receptors that play a vital role in various biological processes, in particular, cell survival, cell proliferation, and cell differentiation. These cellular processes are composed of multitiered signaling cascades of kinases starting from ligand binding to extracellular domains of RTKs that activate the entire pathways through tyrosine phosphorylation of the receptors and downstream effectors. A previous study reported that, based on proteomics data, RTKs were a major candidate target for osteosarcoma. In this study, activation profiles of six candidate RTKs, including c-Met, c-Kit, VEGFR2, HER2, FGFR1, and PDGFRα, were directly examined from chemonaive fresh frozen tissues of 32 osteosarcoma patients using a multiplex immunoassay. That examination revealed distinct patterns of tyrosine phosphorylation of RTKs in osteosarcoma cases. Unsupervised hierarchical clustering was calculated using Pearson uncentered correlation coefficient to classify RTKs into two groups-Group A (c-Met, c-Kit, VEGFR2, and HER2) and Group B (FGFR1 and PDGFRα)-based on tyrosine phosphorylation patterns. Nonactivation of all Group A RTKs was associated with shorter overall survival in stage IIB osteosarcoma patients. Percentages of tumor necrosis in patients with inactive Group A RTKs were significantly lower than those in patients with at least one active Group A RTK. Paired primary osteosarcoma cells with fresh osteosarcoma tissue were extracted and cultured for cytotoxicity testing. Primary cells with active Group A RTKs tended to be sensitive to doxorubicin and cisplatin. We also found that osteosarcoma cells with active Group A RTKs were more proliferative than cells with inactive Group A RTKs. These findings indicate that the activation pattern of Group A RTKs is a potential risk stratification and chemoresponse predictor and might be used to guide the optimum chemotherapy regimen for osteosarcoma patients.

Exploring targeted therapy of osteosarcoma using proteomics data

Despite multimodal therapeutic treatments of osteosarcoma (OS), some patients develop resistance to currently available regimens and eventually end up with recurrent or metastatic outcomes. Many attempts have been made to discover effective drugs for improving outcome; however, due to the heterogeneity of the disease, new therapeutic options have not yet been identified. This study aims to explore potential targeted therapy related to protein profiles of OS. In this review of proteomics studies, we extracted data on differentially expressed proteins (DEPs) from archived literature in PubMed and our in-house repository. The data were divided into three experimental groups, DEPs in 1) OS/OB: OS vs osteoblastic (OB) cells, 2) metastasis: metastatic vs non-metastatic sublines plus fresh tissues from primary OS with and without pulmonary metastasis, and 3) chemoresistance: spheroid (higher chemoresistance) vs monolayer cells plus fresh tissues from biopsies from good and poor responders. All up-regulated protein entities in the list of DEPs were sorted and cross-referenced with identifiers of targets of US Food and Drug Administration (FDA)-approved agents and chemical inhibitors. We found that many targets of FDA-approved antineoplastic agents, mainly a group of epigenetic regulators, kinases, and proteasomes, were highly expressed in OS cells. Additionally, some overexpressed proteins were targets of FDA-approved non-cancer drugs, including immunosuppressive and antiarrhythmic drugs. The resulting list of chemical agents showed that some transferase enzyme inhibitors might have anticancer activity. We also explored common targets of OS/OB and metastasis groups, including amidophosphoribosyltransferase (PPAT), l-lactate dehydrogenase B chain (LDHB), and pyruvate kinase M2 (PKM2) as well as the common target of all categories, cathepsin D (CTSD). This study demonstrates the benefits of a text mining approach to exploring therapeutic targets related to protein expression patterns. These results suggest possible repurposing of some FDA-approved medicines for the treatment of OS and using chemical inhibitors in drug screening tests.

Elevated O-GlcNAcylation of Extracellular Vesicle Proteins Derived from Metastatic Colorectal Cancer Cells

BACKGROUND

O-GlcNAcylation is a single sugar attachment of serine and/or threonine residues on intracellular proteins. Recent reports reveal that it can modify several secretory proteins; however, the underlying mechanisms are largely unexplored.

MATERIALS AND METHODS

To investigate whether extracellular vesicles (EVs) carry secretory O-GlcNAc-modified proteins that were isolated from colorectal cancer (CRC) cells, two-dimensional gel electrophoresis followed with O-GlcNAc immunoblotting and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were applied.

RESULTS

It was revealed that the O-GlcNAc modification of many EV proteins was increased in metastatic cells. Among these, transitional endoplasmic reticulum ATPase (TER ATPase) and RuVB-like1 were successfully confirmed for the O-GlcNAc modification in which the levels were significantly higher in EVs of metastatic CRC cell line.

CONCLUSION

These data, demonstrate that proteins carried by EVs are O-GlcNAc-modified. Importantly, elevated aberrant O-GlcNAcylation of EV proteins might serve as a potential biomarker of metastatic CRC.

Overexpression of KH-type splicing regulatory protein regulates proliferation, migration, and implantation ability of osteosarcoma

Osteosarcoma is a common malignant bone tumor in children and adolescents. The current 5-year survival rate is ~60% and that seems to be reaching a plateau. In order to improve treatment outcomes of osteosarcoma, a better understanding of tumorigenesis and underlying molecular mechanisms is required for searching out possible new treatment targets. This study aimed to identify the potential proteins involving the pathogenesis of osteosarcoma using a proteomics approach. Proteins extracted from primary cell culture of osteosarcoma (n=7) and osteoblasts of cancellous bone (n=7) were studied. Using 2-DE based proteomics and LC-MS/MS analysis, we successfully determined seven differentially expressed protein spots. Four upregulated proteins and three downregulated proteins were observed in this study in which KH-type splicing regulatory protein (KSRP) was selected for further exploration. KSRP was significantly upregulated in osteosarcoma cells compared to osteoblasts using western blot assay. In addition, immunohistochemistry demonstrated that KSRP was also highly expressed in osteosarcoma tissue of independent cases from the experimental group. More importantly, KSRP silencing of osteosarcoma cell lines significantly decreased cell proliferation, migration ability, as well as implantation and growth ability in chick chorioallantoic membrane assay. Taken together, these findings demonstrate, that KSRP plays important roles in regulatory controls of osteosarcoma pathogenesis and serves as a potentially therapeutic target of osteosarcoma.

AgeStandardized Incidence Rates and Survival of Osteosarcoma in Northern Thailand

Osteosarcoma is a common primary malignant bone tumor in children and adolescents. Recent worldwide average incidences of osteosarcoma in people aged 0 to 24 years were 4.3 and 3.4 per million, respectively, with a ratio of 1.4:1. However, data on the incidence of osteosarcoma in Thailand are limited. This study analyzed the incidence of osteosarcoma in the upper northern region of Thailand, with a population of 5.85 million people (8.9% of the total Thai population), using data for the years 1998 to 2012, obtained from the Chiang Mai Cancer Registry (CMCR) at Chiang Mai University Hospital and the Lampang Cancer Registry (LCR) at the Lampang Cancer Hospital, a total of 144 cases. The overall annual incidence of osteosarcoma was 1.67 per million with a male:female ratio of 1.36:1. Incidences by age group (male and female) at 0 to 24, 25 to 59 and over 60 years were 3.5 (3.9 and 3.0), 0.8 (0.9 and 0.6), and 0.7 (0.8 and 0.5), respectively. The peak incidence occurred at 15 to 19 years for males and at 10 to 14 years for females. The median survival time was 18 months with a 5year survival rate of 43%. Neither the age group nor the 5year interval period of treatment was significantly correlated with survival during the 15year period studied.

Reliability and Validity of the Nepali Wolf Motor Function Test following Cross-cultural Adaptation

Background The Wolf motor function test is a standardized, reliable and valid performance-based measure, which evaluates upper-extremity function. Neither there is any evidence of neurological measure in Nepali nor has this tool been cross-culturally adapted to date. Objective To cross-culturally translate and evaluate reliability and validity of Nepali Wolf motor function test. Method Two forward-translators translated the original version into Nepali. After synthesizing, two back- translators translated it into English. The expert committee consolidated and derived a final Nepali version. Two assessors pretested on three participants to confirm that the original concept of the tool is preserved. The agreement and correlation between back-translators were evaluated. The inter- and intra-rater reliability and agreement of two physiotherapists on eight participants were demonstrated through intra-class-correlation- coefficient and weighted-kappa for time and functional ability respectively. Criterion validity was explored against Fugl- Meyer assessment scale. Result A cross-culturally adapted Nepali Wolf motor function test was pretested and ensured that the Nepali version was still retaining its equivalence (rho: 0.74 to 1.0 for time, 0.82 to 1.0 for functional ability). Good-to- excellent inter- and intra-rater reliability {intra-class-correlation-coefficient(2,1) and (3,1): 0.80 to 1.0 and 0.81 to 1.0 respectively} were demonstrated. Excellent agreement (kappa 0.90, p <0.00) and good correlation (rho 0.57 to 1.0) between back-translators were found. An adequate criterion validity (rho -0.95 for time, 0.91 for functional ability) against Fugl-Meyer assessment scale has been demonstrated. Conclusion A cross-culturally adapted Nepali Wolf motor function test, preserving its original concept, was developed, and the reliability and validity of the tool on individuals with stroke has been demonstrated.

Prevalence and Survival Patterns of Patients with Bone Metastasis from Common Cancers in Thailand

BACKGROUND

Bone metastasis is a single condition but presents with various patterns and severities. Skeletal- related events (SREs) deteriorate overall performance status and reduce quality of life. However, guidelines for early detection and management are limited. This study includes a survey of the prevalence of bone metastasis in cases with common cancers in Thailand as well as a focus on survival patterns and SREs.

MATERIALS AND METHODS

A retrospective cohort analysis was conducted using a database of the Chiang Mai Cancer Registry and the Musculoskeletal Tumor Registry of the OLARN Center, Chiang Mai University. The prevalence of bone metastasis from each type of primary cancer was noted and time-to-event analysis was performed to estimate cancer survival rates after bone metastasis.

RESULTS

There were 29,447 cases of the ten most common cancers in Thailand, accounting for 82.2% of the entire cancer registry entries during the study period. Among those cases, there were 2,263 with bone metastases, accounting for 7.68% of entries. Bone metastasis from lung, liver, breast, cervix and prostate are common in the Thai population, accounting for 83.4% of all positive cases. The median survival time of all was 6 months. Of the bone metastases, 48.9% required therapeutic intervention, including treatment of spinal cord and nerve root compression, pathological fractures, and bone pain.

CONCLUSIONS

The frequency of the top five types of bone metastasis in Thailand were different from the frequencies in other countries, but corresponded to the relative prevalence of the cancers in Thailand and osteophilic properties of each cancer. The results of this study support the establishment of country specific guidelines for primary cancer identification with skeletal lesions of unknown origin. In addition, further clinical studies of the top five bone metastases should be performed to develop guidelines for optimal patient management during palliative care.

Aberrant O-GlcNAcylated Proteins: New Perspectives in Breast and Colorectal Cancer

Increasing glucose consumption is thought to provide an evolutionary advantage to cancer cells. Alteration of glucose metabolism in cancer influences various important metabolic pathways including the hexosamine biosynthesis pathway (HBP), a relatively minor branch of glycolysis. Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), an end product of HBP, is a sugar substrate used for classical glycosylation and O-GlcNAcylation, a post-translational protein modification implicated in a wide range of effects on cellular functions. Emerging evidence reveals that certain cellular proteins are abnormally O-GlcNAc modified in many kinds of cancers, indicating O-GlcNAcylation is associated with malignancy. Since O-GlcNAc rapidly on and off modifies in a similar time scale as in phosphorylation and these modifications may occur on proteins at either on the same or adjacent sites, it suggests that both modifications can work to regulate the cellular signaling pathways. This review describes the metabolic shifts related to the HBP, which are commonly found in most cancers. It also describes O-GlcNAc modified proteins identified in primary breast and colorectal cancer, as well as in the related cancer cell lines. Moreover, we also discuss the potential use of aberrant O-GlcNAcylated proteins as novel biomarkers of cancer.

Aberrant O-GlcNAc-modified proteins expressed in primary colorectal cancer

O-GlcNAcylation is a post-translational modification of serine and threonine residues which is dynamically regulated by 2 enzymes; O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) that catalyze the addition and removal of a single N-acetylglucosamine (GlcNAc) molecule, respectively. This modification is thought to be a nutrient sensor in highly proliferating cells via the hexosamine biosynthesis pathway, a minor branch of glycolysis. Although emerging evidence suggests that O-GlcNAc modification is associated with many types of cancer, identification of O-GlcNAc-modified proteins and their role in cancer remain unexplored. In the present study, we demonstrated that O-GlcNAcylation is increased in primary colorectal cancer tissues, and that this augmentation is associated with an increased expression of OGT levels. Using 2-dimensional O-GlcNAc immunoblotting and LC-MS/MS analysis, 16 proteins were successfully identified and 8 proteins showed an increase in O-GlcNAcylation, including cytokeratin 18, heterogeneous nuclear ribonucleoproteins A2/B1 (hnRNP A2/B1), hnRNP H, annexin A2, annexin A7, laminin-binding protein, α-tubulin and protein DJ-1. Among these identified proteins, annexin A2 was further confirmed to show overexpression of O-GlcNAc in all cancer samples. The results, therefore, indicate that aberrant O-GlcNAcylation of proteins is associated with colorectal cancer and that identification of O-GlcNAc-modified proteins may provide novel biomarkers of cancer.

Proteomic analysis and abrogated expression of O-GlcNAcylated proteins associated with primary breast cancer

O-GlcNAcylation is a dynamic PTM of nuclear and cytoplasmic proteins, regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase, which catalyze the addition and removal of O-GlcNAc, respectively. This modification is associated with glucose metabolism, which plays important roles in many diseases including cancer. Although emerging evidence reveals that some tumor-associated proteins are O-GlcNAc modified, the total O-GlcNAcylation in cancer is still largely unexplored. Here, we demonstrate that O-GlcNAcylation was increased in primary breast malignant tumors, not in benign tumors and that this augmentation was associated with increased expression of OGT level. Using 2D O-GlcNAc immnoblotting and LC-MS/MS analysis, we successfully identified 29 proteins, with seven being uniquely O-GlcNAcylated or associated with O-GlcNAcylation in cancer. Of these identified proteins, some were related to the Warburg effect, including metabolic enzymes, proteins involved in stress responses and biosynthesis. In addition, proteins associated with RNA metabolism, gene expression, and cytoskeleton were highly O-GlcNAcylated or associated with O-GlcNAcylation. Moreover, OGT knockdown showed that decreasing O-GlcNAcylation was related to inhibition of the anchorage-independent growth in vitro. These data indicate that aberrant protein O-GlcNAcylation is associated with breast cancer. Abnormal modification of these O-GlcNAc-modified proteins might be one of the vital malignant characteristics of cancer.