Role Of Secreted Protein Acidic And Rich In Cysteine Research Articles

Suppression of SPARC Ameliorates Ovalbumin-induced Airway Remodeling via TGFβ1/Smad2 in Chronic Asthma.

Airway remodeling is a critical feature of asthma. Secreted protein acidic and rich in cysteine (SPARC), which plays a cardinal role in regulating cell-matrix interactions, has been implicated in various fibrotic diseases. However, the effect of SPARC in asthma remains unknown. We studied the expression of SPARC in human bronchial epithelial cells and serum of asthmatics as well as in the lung tissues of chronic asthma mice. The role of SPARC was examined by using a Lentivirus-mediated SPARC knockdown method in the ovalbumin (OVA)-induced asthma mice. The biological processes regulated by SPARC were identified using RNA sequencing. The function of SPARC in the remodeling process induced by transforming growth factor β1 (TGFβ1) was conducted by using SPARC small interfering RNA (siRNA) or recombinant human SPARC protein in 16HBE cells. We observed that SPARC was up-regulated in human bronchial epithelia of asthmatics and the asthmatic mice. The levels of serum SPARC in asthmatics were also elevated and negatively correlated with the forced expiratory volume in one second (FEV1) to forced vital capacity ratio (FVC) (r = -0.485, P < 0.01) and FEV1 (%predicted) (r = -0.425, P = 0.001). In the chronic asthmatic mice, Lentivirus-mediated SPARC knockdown significantly decreased airway remodeling and airway hyper-responsiveness. According to gene set enrichment analysis, negatively enriched pathways found in the OVA + short hairpin-SPARC group included ECM organization and collagen formation. In the lung function studies, knockdown of SPARC by siRNA reduced the expression of remodeling-associated biomarkers, cell migration, and contraction by blocking the TGFβ1/Smad2 pathway. Addition of human recombinant SPARC protein promoted the TGFβ1-induced remodeling process, cell migration, and contraction in 16HBE cells via the TGFβ1/Smad2 pathway. Our studies provided evidence for the involvement of SPARC in the airway remodeling of asthma via the TGFβ1/Smad2 pathway.

TGF-β1 upregulates secreted protein acidic and rich in cysteine expression in human granulosa-lutein cells: a potential mechanism for the pathogenesis of ovarian hyperstimulation syndrome

BackgroundOvarian hyperstimulation syndrome (OHSS) is a serious complication during in vitro fertilization (IVF) treatment. The upregulation of ovarian transforming growth factor-beta 1 (TGF-β1) is involved in the development of OHSS. The secreted protein acidic and rich in cysteine (SPARC) is a secreted multifunctional matricellular glycoprotein. Although the regulatory effects of TGF-β1 on SPARC expression have been reported, whether TGF-β1 regulates SPARC expression in the human ovary remains unknown. In addition, the role of SPARC in the pathogenesis of OHSS is unclear.MethodsA steroidogenic human ovarian granulosa-like tumor cell line, KGN, and primary culture of human granulosa-lutein (hGL) cells obtained from patients undergoing IVF treatment were used as experimental models. OHSS was induced in rats, and ovaries were collected. Follicular fluid samples were collected from 39 OHSS and 35 non-OHSS patients during oocyte retrieval. The underlying molecular mechanisms mediating the effect of TGF-β1 on SPARC expression were explored by a series of in vitro experiments.ResultsTGF-β1 upregulated SPARC expression in both KGN and hGL cells. The stimulatory effect of TGF-β1 on SPARC expression was mediated by SMAD3 but not SMAD2. The transcription factors, Snail and Slug, were induced in response to the TGF-β1 treatment. However, only Slug was required for the TGF-β1-induced SPARC expression. Conversely, we found that the knockdown of SPARC decreased Slug expression. Our results also revealed that SPARC was upregulated in the OHSS rat ovaries and in the follicular fluid of OHSS patients. Knockdown of SPARC attenuated the TGF-β1-stimulated expression of vascular endothelial growth factor (VEGF) and aromatase, two markers of OHSS. Moreover, the knockdown of SPARC reduced TGF-β1 signaling by downregulating SMAD4 expression.ConclusionsBy illustrating the potential physiological and pathological roles of TGF-β1 in the regulation of SPARC in hGL cells, our results may serve to improve current strategies used to treat clinical infertility and OHSS.66JbE8YWJdrsTB-WmCj_-wVideo

The role of SPARC (secreted protein acidic and rich in cysteine) in the pathogenesis of obesity, type 2 diabetes, and non-alcoholic fatty liver disease.

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein with pleiotropic functions, which is expressed in adipose, hepatic, muscular, and pancreatic tissue. Particularly, several studies demonstrated that SPARC is an important player in the context of obesity, diabetes, and fatty liver disease including advanced hepatic fibrosis and hepatocellular carcinoma. Evidence in murine and human samples indicates that SPARC is involved in adipogenesis, cellular metabolism, extracellular matrix modulation, glucose and lipid metabolism, among others. Furthermore, studies in SPARC knockout mouse model showed that SPARC contributes to adipose tissue formation, non-alcoholic fatty liver disease (NAFLD), and diabetes. Hence, SPARC may represent a novel and interesting target protein for future therapeutic interventions or a biomarker of disease progression. This review summarizes the role of SPARC in the pathophysiology of obesity, and extensively revised SPARC functions in physiological and pathological adipose tissue deposition, muscle metabolism, liver, and diabetes-related pathways.

Secreted protein acidic and rich in cysteine (SPARC) and a disintegrin and metalloproteinase with thrombospondin type 1 motif (ADAMTS1) increments by the renin-angiotensin system induce renal fibrosis in deoxycorticosterone acetate-salt hypertensive rats

Secreted protein acidic and rich in cysteine (SPARC), an extracellular matrix (ECM) protein, was recently shown to induce collagen deposition through the production of a disintegrin and metalloproteinase with thrombospondin type 1 motif (ADAMTS1) in the aging heart. ADAMTS1 regulates ECM turnover by degrading ECM components, and its excessive activation contributes to various pathological states, including fibrosis. The present study investigated the pathophysiological regulation and role of SPARC and ADAMTS1 in renal fibrosis using uninephrectomized rats treated with deoxycorticosterone acetate (DOCA, 40 mg/kg/week, subcutaneously) and salt (1% in drinking water). The administration of DOCA and salt gradually and significantly elevated systolic blood pressure during the 3-week treatment period, induced proteinuria, decreased creatinine clearance, and increased NADPH oxidase-derived superoxide production, malondialdehyde concentrations, and monocyte chemoattractant protein-1 and osteopontin expression in the kidneys. Glomerulosclerosis, fibrillar collagen deposition, and transforming growth factor-β expression increased in a time-dependent manner, and SPARC and ADAMTS1 expression showed a similar pattern to these changes. The angiotensin II type-1 receptor blocker losartan suppressed the overexpression of SPARC and ADAMTS1, and an in vitro exposure to angiotensin II induced the production of both SPARC and ADAMTS1 in renal fibroblast NRK-49F cells. Knockdown of the SPARC gene with small interfering RNA reduced all forms (the 110-kDa latent and 87- and 65-kDa bioactive forms) of ADAMTS1 expression as well as collagen production. These results suggest that SPARC is induced by the renin-angiotensin system and may be a fibrogenic factor, at least in part, by producing ADAMTS1 in hypertensive renal disease.

SPARC Overexpression Promotes Liver Cancer Cell Proliferation and Tumor Growth.

Background: Secreted protein acidic and rich in cysteine (SPARC) plays an important role in cancer development. The roles of SPARC in the liver hepatocellular carcinoma (LIHC) are unclear. Methods: GEPIA2 and UALCAN were used to analyze the SPARC mRNA expression levels in LIHC based on the TCGA database. The GEO database was used to verify the analysis results. Immunohistochemical (IHC) analysis was used to investigate the SPARC protein levels in LIHC tissues. The Kaplan–Meier (KM) plotter was used to analyze the correlation between SPARC and prognosis. The serum SPARC levels were measured by ELISA. CCK8 and murine xenograft models were used to investigate the effect of SPARC on the liver cancer growth in vitro and in vivo. SPARC-correlated genes were screened by LinkedOmics. Results: Based on the TCGA and GEO databases, the analysis showed that the SPARC mRNA expression levels were increased in tumor tissues and peripheral blood mononuclear cell (PBMC) from LIHC compared to normal controls. The IHC analysis showed an increased level of SPARC in LIHC tissues compared to adjacent non-tumor tissues. However, we found that the serum SPARC levels were lower in LIHC than those in healthy controls. The KM plotter showed that there was no significant correlation between the SPARC mRNA levels and overall survival. However, in sorafenib-treated LIHC patients, the high SPARC expression predicts favorable prognosis. Furthermore, the endogenous SPARC overexpression promotes liver cancer cell proliferation in vitro and tumor growth in vivo, while there was no significant effect of exogenous SPARC treatment on liver cancer cell proliferation. Function enrichment analysis of SPARC-correlated genes indicated a critical role of interaction with an extracellular matrix in SPARC-promoting cancer cell proliferation. Conclusion: SPARC mRNAs were increased in LIHC tumor tissues, and SPARC overexpression may promote the liver cancer growth. Further studies are needed to clarify the potential prognostic value of SPARC, both in tissues and in circulation.

Building and destroying synaptic bridges: How do Hevin/Sparcl1, SPARC, and MDGAs modify trans-synaptic neurexin-neuroligin interactions?

Astrocyte-secreted Hevin induces synapse formation by bridging the trans-synaptic organizers, neuroligins and neurexins. In this issue of Structure, Fan etal. (2021) elucidate the structural basis of Hevin's interaction with these molecules and reveal the competitive interplay between Hevin, SPARC, and MDGAs.

SPARC correlates with unfavorable outcome and promotes tumor growth in lung squamous cell carcinoma

Secreted protein acidic and rich in cysteine (SPARC) plays a crucial role in the malignant progression of a number of human cancers. However, the roles of SPARC in lung squamous cell carcinoma (LSCC) remain elusive. In this present study, we first detected SPARC expression and investigated the relationship between SPARC expression and the clinicopathological attributes of LSCC patients. Then we constructed SPARC-overexpression model in LSCC cell line to explore the characteristics of SPARC in LSCC development both in vitro and in vivo. The data demonstrated a remarkably higher level of SPARC in LSCC tissues than in corresponding non-cancerous tissues and elevated SPARC expression was significantly correlated with poor outcome in LSCC patients. Moreover, a serial of phenotypic experiments indicated that SPARC overexpression substantially facilitated the growth and inhibited the apoptosis in LSCC cells and xenografts. Taken together, our results suggest that SPARC is a novel prognostic marker for LSCC prognosis and SPARC significantly promotes LSCC tumorigenesis. Targeting SPARC may provide a novel therapeutic strategy for LSCC management.

SPARC Inhibits Metabolic Plasticity in Ovarian Cancer.

The tropism of ovarian cancer (OvCa) to the peritoneal cavity is implicated in widespread dissemination, suboptimal surgery, and poor prognosis. This tropism is influenced by stromal factors that are not only critical for the oncogenic and metastatic cascades, but also in the modulation of cancer cell metabolic plasticity to fulfill their high energy demands. In this respect, we investigated the role of Secreted Protein Acidic and Rich in Cysteine (SPARC) in metabolic plasticity of OvCa. We used a syngeneic model of OvCa in Sparc-deficient and proficient mice to gain comprehensive insight into the paracrine effect of stromal-SPARC in metabolic programming of OvCa in the peritoneal milieu. Metabolomic and transcriptomic profiling of micro-dissected syngeneic peritoneal tumors revealed that the absence of stromal-Sparc led to significant upregulation of the enzymes involved in glycolysis, TCA cycle, and mitochondrial electron transport chain (ETC), and their metabolic intermediates. Absence of stromal-Sparc increased reactive oxygen species and perturbed redox homeostasis. Recombinant SPARC exerted a dose-dependent inhibitory effect on glycolysis, mitochondrial respiration, ATP production and ROS generation. Comparative analysis with human tumors revealed that SPARC-regulated ETC-signature inversely correlated with SPARC transcripts. Targeting mitochondrial ETC by phenformin treatment of tumor-bearing Sparc-deficient and proficient mice mitigated the effect of SPARC-deficiency and significantly reduced tumor burden, ROS, and oxidative tissue damage in syngeneic tumors. In summary, our findings provide novel insights into the role of SPARC in regulating metabolic plasticity and bioenergetics in OvCa, and shines light on its potential therapeutic efficacy.

SPARC acts as a mediator of TGF-β1 in promoting epithelial-to-mesenchymal transition in A549 and H1299 lung cancer cells.

Migration and metastasis of tumor cells greatly contributes to the failure of cancer treatment. Recently, the extracellular protein secreted protein acidic and rich in cysteine (SPARC) has been reported closely related to tumorigenesis. Some articles have suggested that SPARC promoted metastasis in several highly metastatic tumors. However, there are also some studies shown that SPARC acted as an antitumor factor. SPARC-induced epithelial-to-mesenchymal transition (EMT) in melanoma cells and promoted EMT in hepatocellular carcinoma. Therefore, the role of SPARC in tumorigenesis and its relationship with EMT is still unclear. In this study, we investigated the expression change of SPARC in A549 and H1299 lung cancer cells undergoing EMT process. Our study indicated that SPARC was upregulated in A549 and H1299 cells EMT process. We further investigated the function of SPARC on proliferation, migration, and EMT process of A549 and H1299 cells. Overexpression of SPARC promoted the migration and EMT of A549 and H1299 cells. Knockdown SPARC inhibited the EMT of A549 cells. Overexpression of SPARC induced the increased expression of p-Akt and P-ERK. Furthermore, exogenous SPARC peptide promoted transforming growth factor (TGF)-β1-induced EMT of A549 and H1299 cells. SPARC knockdown partially eliminated TGF-β1 function in inducing EMT of A549 cells. SPARC follistatin-like functional domain reduced the expression of E-cadherin, but had no effect on the expression of p-Akt and p-ERK. In conclusion, we elucidated that SPARC contributes to tumorigenesis by promoting migration and EMT of A549 and H1299 lung cancer cells. These results will provide some new suggestion for lung cancer treatment. © 2018 BioFactors, 44(5):453-464, 2018.

Secreted protein acidic and rich in cysteine functions in colitis via IL17A regulation in mucosal CD4+ T cells.

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycol that regulates cell proliferation, tissue repair, and tumorigenesis. Despite evidence linking SPARC to inflammation, the mechanisms are unclear. Accordingly, the role of SPARC in intestinal inflammation was investigated. Colitis was induced in wild-type (WT) and SPARC knockout (KO) mice using trinitrobenzene sulfonic acid (TNBS). Colons were assessed for damage; leukocyte infiltration; Tnf, Ifng, Il17a, and Il10 mRNA expression; and histology. Cytokine profiling of colonic lamina propria mononuclear cells (LPMCs) was performed by flow cytometry. Naïve CD4+ T cells were isolated from WT and SPARC KO mouse spleens, and the effect of SPARC on Th17 cell differentiation was examined. Recombination activating gene 1 knockout (RAG1 KO) mice reconstituted with T cells from either WT or SPARC KO mice were investigated. Trinitrobenzene sulfonic acid exposure significantly reduced bodyweight and increased mucosal inflammation, leukocyte infiltration, and Il17a mRNA expression in WT relative to SPARC KO mice. The percentage of IL17A-producing CD4+ T cells among LPMCs from KO mice was lower than that in WT mice when both groups were exposed to TNBS. Th17 cell differentiation was suppressed in cells from SPARC KO mice. In the T cell transfer colitis model, RAG1 KO mice receiving T cells from WT mice were more severely affected than those reconstituted with cells from SPARC KO mice. Secreted protein acidic and rich in cysteine accelerates colonic mucosal inflammation via modulation of IL17A-producing CD4+ T cells. SPARC is a potential therapeutic target for conditions involving intestinal inflammation.

Hypermethylation of the SPARC promoter and its prognostic value for prostate cancer

Secreted protein acidic and rich in cysteine (SPARC) is a secreted matricellular glycoprotein and plays a key role in the development of many tissues and organ types. However, the role of SPARC in prostate cancer (PCa) is still controversial. The aim of the present study was to investigate the abnormalities in the expression of SPARC and its promoter hypermethylation in prostate cancers and in correlated clinicopathological profiles. We examined the hypermethylation of the SPARC promoter as a potential mechanism for suppressing SPARC in PCa. The clinicopathological correlation between SPARC and its promoter expression and the prognostic significance of the aberrantly expressed genes were evaluated to identify novel biomarkers of PCa. SPARC expression was decreased in PCa cell lines, which correlated with hypermethylation of the SPARC promoter. Treatment with the demethylating agent 5-Aza-Cdr restored SPARC expression. Seventy percent (145 of 207) of the primary tumors exhibited SPARC hypermethylation, while only 2.6% was found in normal prostate mucosa (n=38). In PCa cases, SPARC hypermethylation was correlated with a poorer prognosis (P=0.005; relative risk 2.659, 95% CI, 1.433‑4.562). Our findings revealed potential diagnostic markers of PCa based on specific hypermethylated CpG sites and also provided new insights of SPARC as a novel biomarker and/or treatment modality for prostate cancer.

Secreted protein acidic and rich in cysteine (SPARC) induces cell migration and epithelial mesenchymal transition through WNK1/snail in non-small cell lung cancer.

The extracellular matrix is a component of physiological microenvironment and a regulator of cellular processes such as migration and proliferation. Secreted Protein Acidic and Rich in Cysteine (SPARC/osteonectin) is an extracellular matrix-associated glycoprotein involved in the regulation of cell proliferation and cell migration in several types of cancers. However, the role of SPARC in lung cancer is paradoxical and details of the regulatory mechanism are not well-known. In this study, we investigated novel SPARC-mediated signaling pathways. Treatment of SPARC increased cell proliferation, migration, and mesenchymal phenotype in two non-small cell lung cancer cell lines, CL1-5 and H1299. We found that these phenotypes were not regulated by focal adhesion kinase and Src kinase, but were mediated by with no lysine (K) kinase 1 (WNK1). Suppression of WNK1 expression decreased the expression of SPARC-induced N-cadherin and smooth muscle actin. Moreover, Snail, an important transcription factor for regulating epithelial–mesenchymal transition, is also involved in SPARC/WNK1 pathway. In a murine tumor model, SPARC treatment significantly induced phosphorylation of Akt and WNK1 in lung tumor nodules when compared to control mice. In conclusion, these data suggest that WNK1 is a novel molecule in SPARC-mediated mesenchymal signaling pathway in non-small cell lung cancer.

SPARC Interacts with Actin in Skeletal Muscle in Vitro and in Vivo

The cytoskeleton is an integral part of skeletal muscle structure, and reorganization of the cytoskeleton occurs during various modes of remodeling. We previously found that the extracellular matrix protein secreted protein acidic and rich in cysteine (SPARC) is up-regulated and expressed intracellularly in developing muscle, during regeneration and in myopathies, which together suggests that SPARC might serve a specific role within muscle cells. Using co-immunoprecipitation combined with mass spectrometry and verified by staining for direct protein-protein interaction, we find that SPARC binds to actin. This interaction is present in regenerating myofibers of patients with Duchenne muscular dystrophy, polymyositis, and compartment syndrome. Analysis of the α-, β-, and γ-actin isoforms in SPARC knockout myoblasts reveals a changed expression pattern with dominance of γ-actin. In SPARC knockout mice, we performed an injury study to investigate whether lack of SPARC would compromise the ability to repair muscle. We report that these mice develop normal skeletal muscle with retained ability to regenerate. However, when we subject muscle from SPARC-deficient mice to an invitro fatigue stimulation protocol, we find a defective force recovery. Therefore, SPARC appears to be an important modulator of the actin cytoskeleton, implicating maintenance of muscular function. This direct interaction with actin suggests a new role of SPARC during tissue remodeling.

Overexpression of SPARC correlates with poor prognosis in patients with cervical carcinoma and regulates cancer cell epithelial-mesenchymal transition.

Secreted protein acidic and rich in cysteine (SPARC) is associated with the progression of numerous types of cancer. However, the role of SPARC in the progression of cervical cancer has not yet been adequately elucidated. In the current study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were employed to evaluate the mRNA and protein expression of SPARC in normal cervical tissue, cervical intraepithelial neoplasia (CIN) and cervical cancer. In addition, three epithelial-mesenchymal transition (EMT) markers (E-cadherin, N-cadherin and vimentin) were detected by immunohistochemistry in the same specimens, and an enzyme-linked immunosorbent assay was conducted to detect the serum levels of SPARC in patients with cervical neoplasia. In highly invasive subclones of human cervical carcinoma cells, HeLa-1 and SiHa-1, lentiviral transfections were performed and RT-qPCR and western blot were used to investigate the effects of downregulated EGF-containing fibulin-like extracellular matrix protein 1 on the expression of E-cadherin, N-cadherin and vimentin. The results revealed that, in cervical carcinoma tissue, SPARC expression was significantly upregulated in a manner that positively correlated with N-cadherin and vimentin expression, and negatively correlated with E-cadherin expression. SPARC overexpression and high serum levels were significantly associated with the progression of cervical cancer and adverse prognosis of cervical cancer patients. Downregulation of SPARC can markedly reduce the expression of N-cadherin and vimentin and increase the expression of E-cadherin. Thus, overexpression of SPARC is significantly associated with poor prognostic clinicopathological characteristics in cervical carcinoma, and may be important in EMT. The results of the current study suggest that SPARC may be a potential therapeutic option for individuals diagnosed with cervical carcinoma.

SPARC: A Potential Prognostic and Therapeutic Target in Pancreatic Cancer.

Pancreatic cancer is a complex and heterogeneous disease that often lacks disease-specific symptoms in early stages. The malignancy is currently the fourth leading cause of cancer-related death in Western countries. In advanced stages, the overall 5-year survival is less than 1% to 2%. Most available treatments lack convincing cost-efficiency determinations and are generally not associated with relevant success rates. Targeting stromal components and stromal depletion is currently becoming an area of extensive research in pancreatic cancer. In this context, a glycoprotein, SPARC (secreted protein acidic and rich in cysteine) appears to play a central role. Still, the role of SPARC in carcinogenesis is controversial because conflicting results have been reported, and the pathways involved in SPARC signaling are not well established. Nonetheless, SPARC is highly expressed in the tumor stroma, principally in peritumoral fibroblasts, and the overexpression of SPARC in this compartment is associated with poorer prognosis. Interestingly, it has been suggested that SPARC present in the tumor stroma could sequester albumin-bound paclitaxel, enhancing the delivery of paclitaxel into the tumor microenvironment. In the present review, we summarize the known associations between SPARC and pancreatic cancer. Moreover, present and future therapies comprising SPARC-targeting are discussed.

Abstract 5200: Significance of SPARC expression as the predict factor of the therapeutic effect of nab-PTX in gastric cancer

Abstract Background: Gastric cancer is the most frequent cancer-related cause of death second only to lung cancer. Despite recent advances in chemotherapy and surgical techniques, 5-year survival for advanced or metastatic gastric cancer is around 5-20%. Chemotherapy is the standard palliative treatment in patients with an acceptable clinical status because it provides better survival and quality of life than supportive care. In Japan, paclitaxel (PTX) is commonly used as second-line chemotherapy for gastric cancer patients in practice, based on experiences with breast cancer and non-small-cell lung cancer. Nanoparticle albumin-bound paclitaxel (nab-PTX) is an intravenously administered microtubule inhibitor. Recently, nab-paclitaxel has become an option for patients with unresectable or recurrent gastric cancer who experienced progression despite 1st line chemotherapy. Secreted protein, acidic and rich in cysteine (SPARC) has the ability to bind albumin with a high affinity, therefore patients with SPARC expressing tumors could benefit from nab-paclitaxel treatment as the drug can be transported to the tumor in a targeted way and accumulates within at the tissue. SPARC was reported to be overexpressed in a variety of human malignancies, including glioma, colorectal, breast, esophageal, prostate, bladder, and thyroid carcinomas. SPARC plays multi-faceted contextual roles depending on the cancer type and whether it is produced by cancer cells or surrounding stromal cells. It has been reported that immunostaining of SPARC in these tumors revealed increased frequency and intensity of SPARC expression in fibroblasts rather than in tumor cells. Overexpression of the SPARC gene was observed in human gastric cancer, too. It has been suggested that this might lead to a higher effectivity and a better tolerance for the drug with less side effects. The aim of this study is to clarify the role of SPARC in gastric cancer. Method: The SPARC expression was assessed in 15 gastric cancer samples following surgical resection or biopsy used by immunohistochemistry. Result: The progression-free survival was longer in the SPARC high expression group than in the SPARC low expression group (p = 0.013). Overall survival was not significantly different in experimental groups. The incidences of grade 3 or 4 adverse effects were not different in both experimental groups. We also compared the expression of SPARC between biopsy samples before chemotherapy and resected sample after chemotherapy of the same cases. It was no difference in the SPARC expression of the samples before and after the chemotherapy. Conclusion: The expression of SPARC has been suggested to be a useful indicator for predicting the therapeutic effect of nab-PTX in gastric cancer. Citation Format: Yuki Kiyozumi, Junji Kurashige, Shiro Iwagami, Kenichi Nakamura, Mayuko Ohuchi, Daisuke Izumi, Keisuke Kosumi, Kazuto Harada, Ryuma Tokunaga, Yukiharu Hiyoshi, Yoshifumi Baba, Yasuo Sakamoto, Yuji Sakamoto, Naoya Yoshida, Hideo Baba. Significance of SPARC expression as the predict factor of the therapeutic effect of nab-PTX in gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5200. doi:10.1158/1538-7445.AM2015-5200

Gene expression profiling in myelodysplastic syndrome after SPARC overexpression associated with Ara-C.

Secreted protein acidic and rich in cysteine (SPARC) is involved in many biological processes, including erythropoiesis and cell proliferation. However, the role of SPARC in myelodysplastic syndrome (MDS) remains to be elucidated. Pyrimidine analogue cytosine arabinoside (Ara-C) is among the most effective agents used in the treatment of acute leukemia. The aim of the present study was to determine whether the chemotherapeutic activity of Ara-C was enhanced by the overexpression of SPARC. DNA microarray technology and RNA sequencing were employed to examine differential gene expression in the apoptosis signaling pathway after gene change occurred in cells following drug treatment. The results showed that upregulation of the expression of SPARC induced SKM-1 cell death and inhibited proliferation. Additionally, the apoptotic rate of SPARC overexpression combined with Ara-C increased significantly. Transcription factors CPBP and ZNF333 regulated the 69 genes and long non-coding RNA (lncRNA). Moreover, the mRNA and protein expression of apoptosis-related genes in the DNA microarray results were increased. These results suggest that SPARC expression changes with Ara-C, revealing a possible application in the treatment of MDS.

Transdisciplinary Approach for Sarcopenia. Molecular mechanism of sarcopenia : The role of skeletal muscle niche component SPARC in the regulation of myogenesis and adipogenesis and its alteration with age

Sarcopenia, an age-related decline in skeletal muscle mass and strength, causes the decline of the quality of life in the elderly. The age-related alteration in the differentiation potency of satellite cells, myogenic tissue specific stem cells in skeletal muscle, and preadipocytes in skeletal muscle is possibly involved in the disruption of homeostasis in skeletal muscle. The differentiation of the cells is affected by the microenvironment surrounding the cells, called niche. Here, we focused on SPARC (secreted protein acidic and rich in cysteine) as a secreted glycoprotein existing in the niche. We review the roles of SPARC on the differentiation of satellite cells and preadipocytes in the muscle and their alteration with age.

Secreted protein acidic and rich in cysteine inhibits the growth of human pancreatic cancer cells with G1 arrest induction.

Aberrant secreted protein acidic and rich in cysteine (SPARC) expression has been reported to play an important role in the tumor development. However, the pattern and the role of SPARC in pancreatic cancer remain largely unknown. Therefore, we further deciphered the role of SPARC played in pancreatic cancer. We first evaluated the SPARC expression in human pancreatic cancer tissues and pancreatic cancer cells. Then we forced expression and silenced SPARC expression in pancreatic cancer cell lines MIA PaCa2 and PANC-1, respectively, using lentivirus vectors. We characterized the stable cells in vitro. In this study, we found that SPARC expression was weak in cancer cells in specimens which negatively correlated with the expression level of phosphorylated pRB and poorer outcome. Moreover, our results demonstrated that SPARC negatively regulated pancreatic cell growth in vitro. Furthermore, we disclosed that the activation of p53 and p27(Kip1) may involve in the effect of SPARC on pancreatic cancer cells. SPARC is downregulated in pancreatic cancer cells and retards the growth of pancreatic cancer cell. Taken together, these results indicate SPARC may be a potential target for pancreatic cancer therapy.

SPARC expression is negatively correlated with clinicopathological factors of gastric cancer and inhibits malignancy of gastric cancer cells

Secreted protein acidic and rich in cysteine (SPARC) is a glycoprotein which plays multiple roles in different types of cancer. Our previous study showed that SPARC overexpression inhibited the growth and angiogenesis of tumors, and reduced expression of vascular endothelial growth factor (VEGF). However, the relationship between SPARC expression and clinicopathological factors of gastric cancer (GC) is controversial, and the role of SPARC in GC remains unclear. We evaluated expression of SPARC in 65 human GC tissues using immunohistochemistry (IHC). The results indicated that SPARC expression was negatively correlated with clinicopathological factors of GC. In vitro assay showed that SPARC overexpression decreased proliferation and clonogenicity by suppressing CD44 expression. In addition, SPARC overexpression inhibited VEGF induced proliferation and arrested cell cycle of GC cells by reducing the activation of VEGFR2, ERK1/2 and AKT signaling pathways. SPARC suppressed the invasion and migration of GC by reducing MMP-7, MMP-9, N-cadherin, Sp1 and p-ERK1/2 expression. In the in vivo assay, cancer metastasis mouse models were established by tail vein injection. The results revealed that the lung metastases of SPARC-overexpressing GC cells in the mice were much fewer than those of control cells.