Expression profiles of two types of human knee-joint cartilage

Optogenetic manipulation of BMP signaling to drive chondrogenic differentiation of hPSCs

Optogenetics is a rapidly advancing technology combining photochemical, optical, and synthetic biology to control cellular behavior. Together, sensitive light-responsive optogenetic tools and human pluripotent stem cell differentiation models have the potential to fine-tune differentiation and unpick the processes by which cell specification and tissue patterning are controlled by morphogens. We used an optogenetic bone morphogenetic protein (BMP) signaling system (optoBMP) to drive chondrogenic differentiation of human embryonic stem cells (hESCs). We engineered light-sensitive hESCs through CRISPR-Cas9-mediated integration of the optoBMP system into the AAVS1 locus. The activation of optoBMP with blue light, in lieu of BMP growth factors, resulted in the activation of BMP signaling mechanisms and upregulation of a chondrogenic phenotype, with significant transcriptional differences compared to cells in the dark. Furthermore, cells differentiated with light could form chondrogenic pellets consisting of a hyaline-like cartilaginous matrix. Our findings indicate the applicability of optogenetics for understanding human development and tissue engineering.

In Vivo Studies of Mesenchymal Stem Cells in the Treatment of Meniscus Injury

This review summarizes the literature of preclinical studies and clinical trials on the use of mesenchymal stem cells (MSCs) to treat meniscus injury and promote its repair and regeneration and provide guidance for future clinical research. Due to the special anatomical features of the meniscus, conservative or surgical treatment can hardly achieve complete physiological and histological repair. As a new method, stem cells promote meniscus regeneration in preclinical research and human preliminary research. We expect that, in the near future, in vivo injection of stem cells to promote meniscus repair can be used as a new treatment model in clinical treatment. The treatment of animal meniscus injury, and the clinical trial of human meniscus injury has begun preliminary exploration. As for the animal experiments, most models of meniscus injury are too simple, which can hardly simulate the complexity of actual meniscal tears, and since the follow-up often lasts for only 4-12 weeks, long-term results could not be observed. Lastly, animal models failed to simulate the actual stress environment faced by the meniscus, so it needs to be further studied if regenerated meniscus has similar anti-stress or anti-twist features. Despite these limitations, repair of the meniscus by MSCs has great potential in clinics. MSCs can differentiate into fibrous chondrocytes, which can possibly repair the meniscus and provide a new strategy for repairing meniscus injury.

Engineering Anisotropic Meniscus: Zonal Functionality and Spatiotemporal Drug Delivery

Human meniscus is a fibrocartilaginous structure that is crucial for an adequate performance of the human knee joint. Degeneration of the meniscus is often followed by partial or total meniscectomy, which enhances the risk of developing knee osteoarthritis. The lack of a satisfactory treatment for this condition has triggered a major interest in drug delivery (DD) and tissue engineering (TE) strategies intended to restore a bioactive and fully functional meniscal tissue. The aim of this review is to critically discuss the most relevant studies on spatiotemporal DD and TE, aiming for a multizonal meniscal reconstruction. Indeed, the development of meniscal tissue implants should involve a provision for adequate active molecules and scaffold features that take into account the anisotropic ultrastructure of human meniscus. This zonal differentiation is reflected in the meniscus biochemical composition, collagen fiber arrangement, and cell distribution. In this sense, it is expected that a proper combination of advanced DD and zonal TE strategies will play a key role in the future trends in meniscus regeneration. Impact statement Meniscus degeneration is one of the main causes of knee pain, inflammation, and reduced mobility. Currently used suturing procedures and meniscectomy are far from being ideal solutions to the loss of meniscal function. Therefore, drug delivery (DD) and tissue engineering (TE) strategies are currently under investigation. DD systems aim at an in situ controlled release of growth factors, whereas TE strategies aim at mimicking the anisotropy of native meniscus. The goal of this review is to discuss these two main approaches, as well as synergies between them that are expected to lead to a real breakthrough in the field.

Distinct degenerative phenotype of articular cartilage from knees with meniscus tear compared to knees with osteoarthritis

OBJECTIVE

To compare the transcriptome of articular cartilage from knees with meniscus tears to knees with end-stage osteoarthritis (OA).

DESIGN

Articular cartilage was collected from the non-weight bearing medial intercondylar notch of knees undergoing arthroscopic partial meniscectomy (APM; N = 10, 49.7 ± 10.8 years, 50% females) for isolated medial meniscus tears and knees undergoing total knee arthroplasty (TKA; N = 10, 66.0 ± 7.6 years, 70% females) due to end-stage OA. Ribonucleic acid (RNA) preparation was subjected to SurePrint G3 human 8 × 60K RNA microarrays to probe differentially expressed transcripts followed by computational exploration of underlying biological processes. Real-time polymerase chain reaction amplification was performed on selected transcripts to validate microarray data.

RESULTS

We observed that 81 transcripts were significantly differentially expressed (45 elevated, 36 repressed) between APM and TKA samples (≥ 2 fold) at a false discovery rate of ≤ 0.05. Among these, CFD, CSN1S1, TSPAN11, CSF1R and CD14 were elevated in the TKA group, while CHI3L2, HILPDA, COL3A1, COL27A1 and FGF2 were highly expressed in APM group. A few long intergenic non-coding RNAs (lincRNAs), small nuclear RNAs (snoRNAs) and antisense RNAs were also differentially expressed between the two groups. Transcripts up-regulated in TKA cartilage were enriched for protein localization and activation, chemical stimulus, immune response, and toll-like receptor signaling pathway. Transcripts up-regulated in APM cartilage were enriched for mesenchymal cell apoptosis, epithelial morphogenesis, canonical glycolysis, extracellular matrix organization, cartilage development, and glucose catabolic process.

CONCLUSIONS

This study suggests that APM and TKA cartilage express distinct sets of OA transcripts. The gene profile in cartilage from TKA knees represents an end-stage OA whereas in APM knees it is clearly earlier in the degenerative process.

Osteoarthritis and intervertebral disc degeneration: Quite different, quite similar

Intervertebral disc degeneration describes the vicious cycle of the deterioration of intervertebral discs and can eventually result in degenerative disc disease (DDD), which is accompanied by low-back pain, the musculoskeletal disorder with the largest socioeconomic impact world-wide. In more severe stages, intervertebral disc degeneration is accompanied by loss of joint space, subchondral sclerosis, and osteophytes, similar to osteoarthritis (OA) in the articular joint. Inspired by this resemblance, we investigated the analogy between human intervertebral discs and articular joints. Although embryonic origin and anatomy suggest substantial differences between the two types of joint, some features of cell physiology and extracellular matrix in the nucleus pulposus and articular cartilage share numerous parallels. Moreover, there are great similarities in the response to mechanical loading and the matrix-degrading factors involved in the cascade of degeneration in both tissues. This suggests that the local environment of the cell is more important to its behavior than embryonic origin. Nevertheless, OA is widely regarded as a true disease, while intervertebral disc degeneration is often regarded as a radiological finding and DDD is undervalued as a cause of chronic low-back pain by clinicians, patients and society. Emphasizing the similarities rather than the differences between the two diseases may create more awareness in the clinic, improve diagnostics in DDD, and provide cross-fertilization of clinicians and scientists involved in both intervertebral disc degeneration and OA.

Meniscus, articular cartilage and nucleus pulposus: a comparative review of cartilage-like tissues in anatomy, development and function

The degradation of cartilage in the human body is impacted by aging, disease, genetic predisposition and continued insults resulting from daily activity. The burden of cartilage defects (osteoarthritis, rheumatoid arthritis, intervertebral disc damage, knee replacement surgeries, etc.) is daunting in light of substantial economic and social stresses. This review strives to broaden the scope of regenerative medicine and tissue engineering approaches used for cartilage repair by comparing and contrasting the anatomical and functional nature of the meniscus, articular cartilage (AC) and nucleus pulposus (NP). Many review papers have provided detailed evaluations of these cartilages and cartilage-like tissues individually but none have comprehensively examined the parallels and inconsistencies in signaling, genetic expression and extracellular matrix composition between tissues. For the first time, this review outlines the importance of understanding these three tissues as unique entities, providing a comparative analysis of anatomy, ultrastructure, biochemistry and function for each tissue. This novel approach highlights the similarities and differences between tissues, progressing research toward an understanding of what defines each tissue as distinctive. The goal of this paper is to provide researchers with the fundamental knowledge to correctly engineer the meniscus, AC and NP without inadvertently developing the wrong tissue function or biochemistry.

A Porcine Animal Model for Early Meniscal Degeneration - Analysis of Histology, Gene Expression and Magnetic Resonance Imaging Six Months after Resection of the Anterior Cruciate Ligament

BACKGROUND/OBJECTIVE

The menisci of the mammalian knee joint balance the incongruence between femoral condyle and tibial plateau and thus menisci absorb and distribute high loads. Degeneration processes of the menisci lead to pain syndromes in the knee joint. The origin of such degenerative processes on meniscal tissue is rarely understood and may be described best as an imbalance of anabolic and catabolic metabolism. A standardized animal model of meniscal degeneration is needed for further studies. The aim of the current study was to develop a porcine animal model with early meniscal degeneration.

MATERIAL AND METHODS

Resection of the anterior cruciate ligament (ACLR) was performed on the left knee joints of eight Göttingen minipigs. A sham operation was carried out on the right knee joint. The grade of degeneration was determined 26 weeks after the operation using histology and magnetic resonance imaging (MRI). Furthermore, the expression of 14 genes which code for extracellular matrix proteins, catabolic matrix metalloproteinases and inflammation mediators were analyzed.

RESULTS

Degenerative changes were detected by a histological analysis of the medial meniscus after ACLR. These changes were not detected by MRI. In terms of their gene expression profile, these degenerated medial menisci showed a significantly increased expression of COL1A1.

CONCLUSION

This paper describes a new animal model for early secondary meniscal degeneration in the Göttingen minipig. Histopathological evidence of the degenerative changes could be described. This early degenerative changes could not be seen by NMR imaging.

Meniscus repair using mesenchymal stem cells - a comprehensive review

The menisci are a pair of semilunar fibrocartilage structures that play an essential role in maintaining normal knee function. Injury to the menisci can disrupt joint stability and lead to debilitating results. Because natural meniscal healing is limited, an efficient method of repair is necessary. Tissue engineering (TE) combines the principles of life sciences and engineering to restore the unique architecture of the native meniscus. Mesenchymal stem cells (MSCs) have been investigated for their therapeutic potential both in vitro and in vivo. This comprehensive review examines the English literature identified through a database search using Medline, Embase, Engineering Village, and SPORTDiscus. The search results were classified based on MSC type, animal model, and method of MSC delivery/culture. A variety of MSC types, including bone marrow-derived, synovium-derived, adipose-derived, and meniscus-derived MSCs, has been examined. Research results were categorized into and discussed by the different animal models used; namely murine, leporine, porcine, caprine, bovine, ovine, canine, equine, and human models of meniscus defect/repair. Within each animal model, studies were categorized further according to MSC delivery/culture techniques. These techniques included direct application, fibrin glue/gel/clot, intra-articular injection, scaffold, tissue-engineered construct, meniscus tissue, pellets/aggregates, and hydrogel. The purpose of this review is to inform the reader about the current state and advances in meniscus TE using MSCs. Future directions of MSC-based meniscus TE are also suggested to help guide prospective research.

Quantitative tracking of passage and 3D culture effects on chondrocyte and fibrochondrocyte gene expression

Success in cartilage and fibrocartilage tissue engineering relies heavily on using an appropriate cell source. Many different cell sources have been identified, including primary and stem cells, along with experimental strategies to obtain the required number of cells or to induce chondrogenesis. However, no definitive method exists to quantitatively evaluate the similarity of the resulting cell phenotypes to those of the native cells between candidate strategies. In this study, we develop an integrative approach to enable such evaluations by deriving, from gene expression profiles, two quantitative metrics representing the nearest location within the range of native cell phenotypes and the deviation from it. As an example application to evaluating potential cell sources for cartilage or meniscus tissue engineering, we examine phenotypic changes of juvenile and adult articular chondrocytes and fibrochondrocytes across multiple passages and subsequent 3D culture. A substantial change was observed in cell phenotype due to the isolation process itself, followed by a clear progression toward the outer meniscal cell phenotype with passage. The new metrics also indicated that 3D culture moderately reduced the passage-induced deviation from the native meniscal phenotypes for juvenile chondrocytes and adult fibrochondrocytes, which was not obvious through examination of individual gene expressions. However, brief 3D culture alone did not move any of the cells towards an inner meniscal phenotype, the most relevant target for meniscal tissue engineering. This integrative approach of examining and combining multiple gene expressions can be used to evaluate various other tissue-engineering strategies to direct cells toward the desired phenotype. Copyright © 2015 John Wiley & Sons, Ltd.

Clinical Outcome 3 Years After Autologous Chondrocyte Implantation Does Not Correlate With the Expression of a Predefined Gene Marker Set in Chondrocytes Prior to Implantation but Is Associated With Critical Signaling Pathways

Background:

There is a need for tools to predict the chondrogenic potency of autologous cells for cartilage repair.

Purpose:

To evaluate previously proposed chondrogenic biomarkers and to identify new biomarkers in the chondrocyte transcriptome capable of predicting clinical success or failure after autologous chondrocyte implantation.

Study Design:

Controlled laboratory study and case-control study; Level of evidence, 3.

Methods:

Five patients with clinical improvement after autologous chondrocyte implantation and 5 patients with graft failures 3 years after implantation were included. Surplus chondrocytes from the transplantation were frozen for each patient. Each chondrocyte sample was subsequently thawed at the same time point and cultured for 1 cell doubling, prior to RNA purification and global microarray analysis. The expression profiles of a set of predefined marker genes (ie, collagen type II α1 [COL2A1], bone morphogenic protein 2 [BMP2], fibroblast growth factor receptor 3 [FGFR3], aggrecan [ACAN], CD44, and activin receptor–like kinase receptor 1 [ACVRL1]) were also evaluated.

Results:

No significant difference in expression of the predefined marker set was observed between the success and failure groups. Thirty-nine genes were found to be induced, and 38 genes were found to be repressed between the 2 groups prior to autologous chondrocyte implantation, which have implications for cell-regulating pathways (eg, apoptosis, interleukin signaling, and β-catenin regulation).

Conclusion:

No expressional differences that predict clinical outcome could be found in the present study, which may have implications for quality control assessments of autologous chondrocyte implantation. The subtle difference in gene expression regulation found between the 2 groups may strengthen the basis for further research, aiming at reliable biomarkers and quality control for tissue engineering in cartilage repair.

Clinical Relevance:

The present study shows the possible limitations of using gene expression before transplantation to predict the chondrogenic and thus clinical potency of the cells. This result is especially important as the chondrogenic potential of the chondrocytes is currently part of quality control measures according to European and American legislations regarding advanced therapies.

Gene signature of the embryonic meniscus

The meniscus is a fibrocartilagenous disc in the knee that protects the joint from damage. Meniscal injuries are common, however repair efforts are largely unsuccessful and are not able to prevent the degenerative changes that result in development of osteoarthritis. Tissue regeneration in adults often recapitulates events of embryonic development, suggesting the regulatory pathways controlling morphogenesis are candidate repair signals. Here we use laser capture microdissection to collect mouse embryonic day 16 (E16) meniscus, articular cartilage, and cruciate ligaments. RNA isolated from these tissues was then used to perform genome-wide microarray analysis. We found 38 genes were differentially expressed between E16 meniscus and articular cartilage and 43 genes were differentially expressed between E16 meniscus and cruciate ligaments. Included in our data set were extracellular matrix proteins, transcription factors, and growth factors, including TGF-β modulators (Lox, Dpt) and IGF-1 pathway members (Igf-1, Igfbp2, Igfbp3, Igfbp5). Ingenuity Pathway Analysis revealed that IGF-1 signaling was enriched in the meniscus compared to the other joint structures, while qPCR showed that Igf-1, Igfbp2, and Igfbp3 expression declined with age. We also found that several meniscus-enriched genes were expressed either in the inner or outer meniscus, establishing that regionalization of the meniscus occurs early in development.

Effect of chondroitinase ABC on adhesion and behavior of synovial membrane-derived mesenchymal stem cells in rabbit partial-thickness chondral defects

Transplanted cells may have difficulty attaching to the surface of partial-thickness chondral lesions because of the anti-adhesive properties of the proteoglycan rich matrix. Therefore, the current study attempts to evaluate the effect of chondroitinase ABC (chABC) on the adhesion and behavior of transplanted synovial membrane-derived mesenchymal stem cells (SDSCs) in rabbit partial-thickness chondral defects. In ex vivo adhesion experiments, chABC treatment (0.1 U/ml) was increased in SDSC attachment to the cartilage explants, and significantly diminished by pretreatment with neutralizing antibody against fibronectin. In the in vivo experiments, 1 day and 4 weeks after the chABC treatment (0.1 and 1 U/ml), the immunoreactivity (IR) against CS-56 (intact chondroitin sulfate antibody) was markedly decreased; however, the IR of 2B6 (stub of the chondroitin 4-sulfate chain), 3B3 (stub of the chondroitin 6-sulfate chain), and fibronectin was increased. At 12 weeks, this IR returned to normal except in the high-dose chABC-treated group (1 U/ml). Furthermore, the attachment of SDSCs to the chondral defects after chABC treatment was increased at 7 days compared with that in the chondral defects pretreated with saline. However, the tissue repaired by SDSCs was negatively stained for type II collagen at 12 weeks. In conclusion, these results showed that the exposure to fibronectin by chABC treatment enhances the attachment of SDSCs to partial-thickness chondral defects. However, the tissue regenerated by SDSCs showed lack of hyaline cartilage regeneration. Thus, to understand the fate of transplanted MSCs in cartilage defect is very important for successful cell therapies.

Comparison of gene expression patterns in articular cartilage and dedifferentiated articular chondrocytes

During monolayer culture, articular chondrocytes dedifferentiate into fibroblast-like cells. The mechanisms underlying this process are poorly understood. We sought to further characterize dedifferentiation by identifying an extended panel of genes that distinguish articular cartilage from dedifferentiated chondrocytes. Thirty-nine candidate marker-genes were identified from previous studies on articular-cartilage gene-expression. Real-time PCR was used to evaluate the mRNA levels for these candidates in calf articular cartilage and dedifferentiated articular chondrocytes. Twenty-two of the candidate marker genes exhibited at least a two-fold difference in gene expression in the two cell types. Twelve of these genes had at least a ten-fold difference in gene expression. Tenascin C (TNC), type I collagen (COL1A1), and hypoxia-inducible factor 1 alpha (HIF1α) showed the highest relative expression levels in dedifferentiated chonodrocytes. Type II collagen (COL2A1), type XI collagen (COL11A2), and superficial zone protein (SZP) showed the highest relative expression levels in articular cartilage. In contrast to previous findings, fibromodulin mRNA, and protein levels were higher in dedifferentiated chondrocytes. Compared to smaller subsets of markers, this panel of 12 highly differentially expressed genes may more precisely distinguish articular cartilage from dedifferentiated chondrocytes. Since many of the genes up-regulated in dedifferentiated chondrocytes are also expressed during cartilage development, dedifferentiated chondrocytes may possess features of cartilage precursor cells.

Transcriptional profiling and biochemical analysis of mechanically induced cartilaginous tissues in a rat model

OBJECTIVE

To characterize patterns of molecular expression that lead to cartilage formation in vivo in a postnatal setting, by profiling messenger RNA expression across the time course of mechanically induced chondrogenesis.

METHODS

Retired breeder Sprague-Dawley rats underwent a noncritical-sized transverse femoral osteotomy. Experimental animals (n = 45) were subjected to bending stimulation (60 degrees cyclic motion in the sagittal plane for 15 minutes/day) of the osteotomy gap beginning on day 10 after the operation. Control animals (n = 32) experienced continuous rigid fixation. Messenger RNA isolated on days 10, 17, 24, and 38 after surgery was analyzed using a microarray containing 608 genes involved in skeletal development, tissue differentiation, fracture healing, and mechanotransduction. The glycosaminoglycan (GAG) content in the stimulated tissues was compared with that in native articular cartilage as a means of assessing the progression of chondrogenic development of the tissues.

RESULTS

The majority of the 100 genes that were differentially expressed were up-regulated in response to mechanical stimulation. Many of these genes are associated with articular cartilage development and maintenance, diarthrodial joint development, cell adhesion, extracellular matrix synthesis, signal transduction, and skeletal development. Quantitative real-time polymerase chain reaction results were consistent with the microarray findings. The GAG content of the stimulated tissues increased over time and was no different from that of articular cartilage on day 38 after surgery.

CONCLUSION

Our findings indicate that mechanical stimulation causes up-regulation of genes that are principally involved in joint cavity morphogenesis and critical to articular cartilage function. Further study of this type of stimulation may identify key signaling events required for postnatal hyaline cartilage formation.

Gene expression profile of multipotent mesenchymal stromal cells: Identification of pathways common to TGFbeta3/BMP2-induced chondrogenesis

Multipotent mesenchymal stromal cells (MSC) display a high potential for the development of novel treatment strategies for cartilage repair. However, the pathways involved in their differentiation to functional non hypertrophic chondrocytes remain largely unknown, despite the work on embryologic development and the identification of key growth factors including TGFbeta, Hh, Wnt and FGF. In this study, we asked if we could identify specific biological networks common to the growth factors used (TGFbeta3 or BMP-2). To address this question, we used DNA microarrays and performed large-scale expression profiling of MSC at different time points during their chondrogenic differentiation. By comparing these data with those obtained during the differentiation of MSC into osteoblasts and adipocytes, we identified 318 genes specific for chondrogenesis and developed a new algorithm to classify the genes according to their kinetic profile. We distributed the selected genes in five classes according to their kinetic of expression. We could reconstruct three phases characterized by functional pathways. The first phase corresponds to cell attachment and apoptosis induction; the second phase is characterized by a proliferation/differentiation step, and the third phase is characterized by a differentiation/hypertrophy pathway. Indeed, these data propose new pathways to understand the complexity of MSC differentiation to chondrocytes.

Activation of KIF4A as a prognostic biomarker and therapeutic target for lung cancer

PURPOSE AND EXPERIMENTAL DESIGN

To identify molecules that might be useful as diagnostic/prognostic biomarkers and as targets for the development of new molecular therapies, we screened genes that were highly transactivated in a large proportion of 101 lung cancers by means of a cDNA microarray representing 27,648 genes. We found a gene encoding KIF4A, a kinesin family member 4A, as one of such candidates. Tumor tissue microarray was applied to examine the expression of KIF4A protein and its clinicopathologic significance in archival non-small cell lung cancer (NSCLC) samples from 357 patients. A role of KIF4A in cancer cell growth and/or survival was examined by small interfering RNA experiments. Cellular invasive activity of KIF4A on mammalian cells was examined using Matrigel assays.

RESULTS

Immunohistochemical staining detected positive KIF4A staining in 127 (36%) of 357 NSCLCs and 19 (66%) of 29 small-cell lung cancers examined. Positive immunostaining of KIF4A protein was associated with male gender (P = 0.0287), nonadenocarcinoma histology (P = 0.0097), and shorter survival for patients with NSCLC (P = 0.0005), and multivariate analysis confirmed its independent prognostic value (P = 0.0012). Treatment of lung cancer cells with small interfering RNAs for KIF4A suppressed growth of the cancer cells. Furthermore, we found that induction of exogenous expression of KIF4A conferred cellular invasive activity on mammalian cells.

CONCLUSIONS

These data strongly implied that targeting the KIF4A molecule might hold a promise for the development of anticancer drugs and cancer vaccines as well as a prognostic biomarker in clinic.

Cancer-testis antigen lymphocyte antigen 6 complex locus K is a serologic biomarker and a therapeutic target for lung and esophageal carcinomas

Gene expression profile analyses of non-small cell lung carcinomas (NSCLC) and esophageal squamous cell carcinomas (ESCC) revealed that lymphocyte antigen 6 complex locus K (LY6K) was specifically expressed in testis and transactivated in a majority of NSCLCs and ESCCs. Immunohistochemical staining using 406 NSCLC and 265 ESCC specimens confirmed that LY6K overexpression was associated with poor prognosis for patients with NSCLC (P = 0.0003), as well as ESCC (P = 0.0278), and multivariate analysis confirmed its independent prognostic value for NSCLC (P = 0.0035). We established an ELISA to measure serum LY6K and found that the proportion of the serum LY6K-positive cases was 38 of 112 (33.9%) NSCLC and 26 of 81 (32.1%) ESCC, whereas only 3 of 74 (4.1%) healthy volunteers were falsely diagnosed. In most cases, there was no correlation between serum LY6K and conventional tumor markers of carcinoembryonic antigen (CEA) and cytokeratin 19-fragment (CYFRA 21-1) values. A combined ELISA for both LY6K and CEA classified 64.7% of lung adenocarcinoma patients as positive, and the use of both LY6K and CYFRA 21-1 increased sensitivity in the detection of lung squamous cell carcinomas and ESCCs up to 70.4% and 52.5%, respectively, whereas the false positive rate was 6.8% to 9.5%. In addition, knocked down of LY6K expression with small interfering RNAs resulted in growth suppression of the lung and esophageal cancer cells. Our data imply that a cancer-testis antigen, LY6K, should be useful as a new type of tumor biomarker and probably as a target for the development of new molecular therapies for cancer treatment.

Subtractive gene expression profiling of articular cartilage and mesenchymal stem cells: serpins as cartilage-relevant differentiation markers

OBJECTIVE

Mesenchymal stem cells (MSCs) are a population of cells broadly discussed to support cartilage repair. The differentiation of MSCs into articular chondrocytes is, however, still poorly understood on the molecular level. The aim of this study was to perform an almost genome-wide screen for genes differentially expressed between cartilage and MSCs and to extract new markers useful to define chondrocyte differentiation stages.

METHODS

Gene expression profiles of MSCs (n=8) and articular cartilage from OA patients (n=7) were compared on a 30,000 cDNA-fragment array and differentially expressed genes were extracted by subtraction. Expression of selected genes was assessed during in vitro chondrogenic differentiation of MSCs and during dedifferentiation of expanded chondrocytes using quantitative and semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Protein secretion was measured by enzyme-linked immunosorbent assay.

RESULTS

Eighty-seven genes were differentially expressed between MSCs and cartilage with a more than three-fold difference. Sixty-seven of them were higher expressed in cartilage and among them 15 genes were previously not detected in cartilage. Differential expression was confirmed for 69% of 26 reanalysed genes by RT-PCR. The profiles of three unknown transcripts and six protease-related molecules were characterised during differentiation. SERPINA1 and SERPINA3 mRNA expression correlated with chondrogenic differentiation of MSCs and dedifferentiation of chondrocytes, and SERPINA1 protein levels in culture supernatants could be correlated alike.

CONCLUSIONS

cDNA-array analysis identified SERPINA1 and A3 as new differentiation-relevant genes for cartilage. Since SERPINA1 secretion correlated with both chondrogenesis of MSCs and dedifferentiation during chondrocyte expansion, it represents an attractive marker for refinement of chondrocyte differentiation.

Fibroblast growth factor receptor 1 oncogene partner as a novel prognostic biomarker and therapeutic target for lung cancer

To screen candidate molecules that might be useful as diagnostic biomarkers or for development of novel molecular-targeting therapies, we previously carried out gene-expression profile analysis of 101 lung carcinomas and detected an elevated expression of FGFR1OP (fibroblast growth factor receptor 1 oncogene partner) in the majority of lung cancers. Immunohistochemical staining using tumor tissue microarrays consisting of 372 archived non-small cell lung cancer (NSCLC) specimens revealed positive staining of FGFR1OP in 334 (89.8%) of 372 NSCLCs. We also found that the high level of FGFR1OP expression was significantly associated with shorter tumor-specific survival times (P < 0.0001 by log-rank test). Moreover, multivariate analysis determined that FGFR1OP was an independent prognostic factor for surgically treated NSCLC patients (P < 0.0001). Treatment of lung cancer cells, in which endogenous FGFR1OP was overexpressed, using FGFR1OP siRNA, suppressed its expression and resulted in inhibition of the cell growth. Furthermore, induction of FGFR1OP increased the cellular motility and growth-promoting activity of mammalian cells. To investigate its function, we searched for FGFR1OP-interacting proteins in lung cancer cells and identified ABL1 (Abelson murine leukemia viral oncogene homolog 1) and WRNIP1 (Werner helicase interacting protein 1), which was known to be involved in cell cycle progression. FGFR1OP significantly reduced ABL1-dependent phosphorylation of WRNIP1 and resulted in the promotion of cell cycle progression. Because our data imply that FGFR1OP is likely to play a significant role in lung cancer growth and progression, FGFR1OP should be useful as a prognostic biomarker and probably as a therapeutic target for lung cancer.

Identification of human leukocyte antigen-A24-restricted epitope peptides derived from gene products upregulated in lung and esophageal cancers as novel targets for immunotherapy

For the development of cancer vaccine therapies, we have searched for possible epitope peptides that can elicit cytotoxic T lymphocytes (CTL) to the TTK protein kinase (TTK), lymphocyte antigen 6 complex locus K (LY6K) and insulin-like growth factor (IGF)-II mRNA binding protein 3 (IMP-3), which were previously identified to be transactivated in the majority of lung and esophageal cancers. We screened 31, 17 and 17 candidate human leukocyte antigen (HLA)-A*2402-binding peptides to parts of TTK, LY6K and IMP-3, respectively. As a result, we successfully established strong CTL clones stimulated by TTK-567 (SYRNEIAYL), LY6K-177 (RYCNLEGPPI) and IMP-3-508 (KTVNELQNL) that have specific cytotoxic activities against the HLA-A24-positive target cells pulsed with the candidate peptides. Subsequent analysis of the CTL clones also revealed their cytotoxic activities against lung and esophageal tumor cells that endogenously express TTK, LY6K or IMP-3. A cold target inhibition assay further confirmed that the CTL cell clones specifically recognized the MHC class I–peptide complex. Our results strongly imply that TTK, LY6K and IMP-3 are novel tumor-associated antigens recognized by CTL, and TTK-567 (SYRNEIAYL), LY6K-177 (RYCNLEGPPI) and IMP-3-508 (KTVNELQNL) are HLA-A24-restricted epitope peptides that can induce potent and specific immune responses against lung and esophageal cancer cells expressing TTK, LY6K and IMP-3.

Large-scale gene expression profiles, differentially represented in osteoarthritic synovium of the knee joint using cDNA microarray technology

Osteoarthritis (OA) is one of the most common age-related chronic disorders of articular cartilage, joints and bone tissue. Diagnosis of OA commonly depends on clinical and radiographic findings. However, changes in cartilage associated with the early stage of OA cannot be detected using radiographs, because significant cartilage degeneration must occur before radiographic findings show alterations of the appearance of cartilage. To identify new biomarkers of OA, we analysed gene expression profiles of synovium from 43 patients with OA, ten patients with rheumatoid arthritis (RA), and eight non-OA/non-RA patients using a novel cDNA microarray chip. We identified 21 genes with simultaneous significant differences in expression between OA and non-OA/non-RA groups and between OA and RA groups. Linear discriminant analysis showed that the three groups could be well separated using those 21 genes. Statistical analysis also revealed that several of the 21 genes were associated with disease progression and clinical presentation. The graphical modelling method indicated that some of the 21 genes are significantly associated with a particular clinical presentation, suggesting biological relationships among those genes. This is the first report of the use of cDNA microarray technology to create large-scale gene expression profiles differentially expressed in situ in OA synovium of the knee joint.

Phosphorylation and activation of cell division cycle associated 8 by aurora kinase B plays a significant role in human lung carcinogenesis

Through genome-wide gene expression analysis of lung carcinomas, we detected in the great majority of lung cancer samples cotransactivation of cell division cycle associated 8 (CDCA8) and aurora kinase B (AURKB), which were considered to be components of the vertebrate chromosomal passenger complex. Immunohistochemical analysis of lung cancer tissue microarrays showed that overexpression of CDCA8 and AURKB was significantly associated with poor prognosis of lung cancer patients. AURKB directly phosphorylated CDCA8 at Ser(154), Ser(219), Ser(275), and Thr(278) and seemed to stabilize CDCA8 protein in cancer cells. Suppression of CDCA8 expression with small interfering RNA against CDCA8 significantly suppressed the growth of lung cancer cells. In addition, functional inhibition of interaction between CDCA8 and AURKB by a cell-permeable peptide corresponding to 20-amino acid sequence of a part of CDCA8 (11R-CDCA8(261-280)), which included two phosphorylation sites by AURKB, significantly reduced phosphorylation of CDCA8 and resulted in growth suppression of lung cancer cells. Our data imply that selective suppression of the CDCA8-AURKB pathway could be a promising therapeutic strategy for treatment of lung cancer patients.

Activation of CDCA1-KNTC2, members of centromere protein complex, involved in pulmonary carcinogenesis

We found cotransactivation of cell division associated 1 (CDCA1) and kinetochore associated 2 (KNTC2), members of the evolutionarily conserved centromere protein complex, in non-small cell lung carcinomas (NSCLC). Immunohistochemical analysis using lung cancer tissue microarray confirmed high levels of CDCA1 and KNTC2 proteins in the great majority of lung cancers of various histologic types. Their elevated expressions were associated with poorer prognosis of NSCLC patients. Knockdown of either CDCA1 or KNTC2 expression with small interfering RNA significantly suppressed growth of NSCLC cells. Furthermore, inhibition of their binding by a cell-permeable peptide carrying the CDCA1-derived 19-amino-acid peptide (11R-CDCA1(398-416)) that correspond to the binding domain to KNTC2 effectively suppressed growth of NSCLC cells. As our data imply that human CDCA1 and KNTC2 seem to fall in the category of cancer-testis antigens, and that their simultaneous up-regulation is a frequent and important feature of cell growth/survival of lung cancer, selective suppression of CDCA1 or KNTC2 activity and/or inhibition of the CDCA1-KNTC2 complex formation could be a promising therapeutic target for treatment of lung cancers.

A predominantly articular cartilage-associated gene, SCRG1, is induced by glucocorticoid and stimulates chondrogenesis in vitro

OBJECTIVE

Cartilage tissue engineering using multipotential human mesenchymal stem cells (hMSCs) is a promising approach to develop treatment for degenerative joint diseases. A key requirement is that the engineered tissues maintain their hyaline articular cartilage phenotype and not proceed towards hypertrophy. It is noteworthy that osteoarthritic articular cartilage frequently contains limited regions of reparative cartilage, suggesting the presence of bioactive factors with regenerative activity. Based on this idea, we recently performed cDNA microarray analysis to identify genes that are strongly expressed only in articular cartilage and encode secreted gene products. One of the genes that met our criteria was SCRG1. This study aims to analyze SCRG1 function in cartilage development using an in vitro mesenchymal chondrogenesis system.

METHODS

Full-length SCRG1 cDNA was subcloned into pcDNA5 vector, and transfected into hMSCs and murine C3H10T1/2 mesenchymal cells, placed in pellet cultures and micromass cultures, respectively. The cultures were analyzed by reverse transcription-polymerase chain reaction for the expression of SCRG1 and cartilage marker genes, and by histological staining for cartilage phenotype.

RESULTS

Induction of SCRG1 expression was seen during in vitro chondrogenesis, and was dependent on dexamethasone (DEX) known to promote chondrogenesis. Immunohistochemistry revealed that SCRG1 protein was localized to the extracellular matrix. Forced expression of SCRG1 in hMSCs suppressed their proliferation, and stimulated chondrogenesis in C3H10T1/2 cells, confirmed by reduced collagen type I and elevated collagen type IIB expression.

CONCLUSION

These results suggest that SCRG1 is involved in cell growth suppression and differentiation during DEX-dependent chondrogenesis. SCRG1 may be of utility in gene-mediated cartilage tissue engineering.

Plakophilin 3 Oncogene as Prognostic Marker and Therapeutic Target for Lung Cancer

We investigated gene expression profiles of non-small cell lung carcinomas (NSCLC) to screen candidate molecules that might be useful as diagnostic markers or for development of novel molecular-targeting therapies. Here we report evidence that a member of the armadillo protein family, plakophilin 3 (PKP3), is a potential molecular target for treatment of lung cancers and might also serve as a prognostic indicator. We documented elevated expression of PKP3 in the great majority of NSCLC samples examined. Treatment of NSCLC cells with small interfering RNAs of PKP3 suppressed growth of the cancer cells; on the other hand, induction of exogenous expression of PKP3 conferred growth-promoting activity on COS-7 cells and enhanced their mobility in vitro. To investigate its function, we searched for PKP3-interacting proteins and identified dynamin 1-like, which was also activated in NSCLC. In addition, a high level of PKP3 expression was associated with poor survival as well as disease stage and node status for patients with lung adenocarcinoma, suggesting an important role of the protein in development and progression of this disease. As our data imply that up-regulation of PKP3 is a frequent and important feature of lung carcinogenesis, we suggest that targeting the PKP3 molecule might hold promise for development of a new therapeutic and diagnostic strategy for clinical management of lung cancers.