Secreted Protein Acidic And Rich In Cysteine Overexpression Research Articles

SPARC overexpression in allogeneic adipose-derived mesenchymal stem cells in dog dry eye model induced by benzalkonium chloride

BackgroundNowadays, companion and working dogs hold significant social and economic importance. Dry eye, also known as dry keratoconjunctivitis (KCS), a common disease in ophthalmology, can readily impact a dog’s working capacity and lead to economic losses. Although there are several medications available for this disease, all of them only improve the symptoms on the surface of the eye, and they are irritating and not easy to use for long periods of time. Adipose-derived mesenchymal stem cells (ADMSC) are promising candidates for tissue regeneration and disease treatment. However, long-term in vitro passaging leads to stemness loss of ADMSC. Here, we aimed to use ADMSC overexpressing Secreted Protein Acidic and Rich in Cysteine (SPARC) to treat 0.25% benzalkonium chloride-treated dogs with dry eye to verify its efficacy. For in vitro validation, we induced corneal epithelial cell (HCECs) damage using 1 µg/mL benzalkonium chloride.MethodsFifteen male crossbred dogs were randomly divided into five groups: normal, dry eye self-healing control, cyclosporine-treated, ADMSC-CMV-treated and ADMSC-OESPARC-treated. HCECs were divided into four groups: normal control group, untreated model group, ADMSC-CMV supernatant culture group and ADMSC-OESRARC supernatant culture group.ResultsSPARC-modified ADMSC had the most significant effect on canine ocular surface inflammation, corneal injury, and tear recovery, and the addition of ADMSC-OESPARC cell supernatant also had a salvage effect on HCECs cellular damage, such as cell viability and cell proliferation ability. Moreover, analysis of the co-transcriptome sequencing data showed that SPARC could promote corneal epithelial cell repair by enhancing the in vitro viability, migration and proliferation and immunosuppression of ADMSC.ConclusionThe in vitro cell test and in vivo model totally suggest that the combination of SPARC and ADMSC has a promising future in novel dry eye therapy.Graphical abstract

SPARC: a potential target for functional nanomaterials and drugs.

Secreted protein acidic and rich in cysteine (SPARC), also termed osteonectin or BM-40, is a matricellular protein which regulates cell adhesion, extracellular matrix production, growth factor activity, and cell cycle. Although SPARC does not perform a structural function, it, however, modulates interactions between cells and the surrounding extracellular matrix due to its anti-proliferative and anti-adhesion properties. The overexpression of SPARC at sites, including injury, regeneration, obesity, cancer, and inflammation, reveals its application as a prospective target and therapeutic indicator in the treatment and assessment of disease. This article comprehensively summarizes the mechanism of SPARC overexpression in inflammation and tumors as well as the latest research progress of functional nanomaterials in the therapy of rheumatoid arthritis and tumors by manipulating SPARC as a new target. This article provides ideas for using functional nanomaterials to treat inflammatory diseases through the SPARC target. The purpose of this article is to provide a reference for ongoing disease research based on SPARC-targeted therapy.

Diosgenin restores memory function via SPARC-driven axonal growth from the hippocampus to the PFC in Alzheimer's disease model mice.

Central nervous system axons have minimal capacity to regenerate in adult brains, hindering memory recovery in Alzheimer's disease (AD). Although recent studies have shown that damaged axons sprouted in adult and AD mouse brains, long-distance axonal re-innervation to their targets has not been achieved. We selectively visualized axon-growing neurons in the neural circuit for memory formation, from the hippocampus to the prefrontal cortex, and showed that damaged axons successfully extended to their native projecting area in mouse models of AD (5XFAD) by administration of an axonal regenerative agent, diosgenin. In vivo transcriptome analysis detected the expression profile of axon-growing neurons directly isolated from the hippocampus of 5XFAD mice. Secreted protein acidic and rich in cysteine (SPARC) was the most expressed gene in axon-growing neurons. Neuron-specific overexpression of SPARC via adeno-associated virus serotype 9 delivery in the hippocampus recovered memory deficits and axonal projection to the prefrontal cortex in 5XFAD mice. DREADDs (Designer receptors exclusively activated by designer drugs) analyses revealed that SPARC overexpression-induced axonal growth in the 5XFAD mouse brain directly contributes to memory recovery. Elevated levels of SPARC on axonal membranes interact with extracellular rail-like collagen type I to promote axonal remodeling along their original tracings in primary cultured hippocampal neurons. These findings suggest that SPARC-driven axonal growth in the brain may be a promising therapeutic strategy for AD and other neurodegenerative diseases.

PS-BPB01-1: SPARC IS INDUCED AT THE EARLY STAGE OF VASCULAR ENDOTHELIAL DYSFUNCTION TO COMPENSATE INFLAMMATION IN DOCA-SALT HYPERTENSIVE RATS

Objective: Extracellular matrix (ECM) regulates various cellular functions as well as provides structural support. SPARC (secreted protein acidic and rich in cysteine) is one of the ECM components, which participates in various cellular functions, especially during morphogenesis and tissue remodeling. We have reported that 1) SPARC, which increases in accordance with renal injury, causes collagen deposition through ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin type 1 motif) production, and 2) renin-angiotensin system is placed in the upstream of SPARC overexpression in the hypertensive rat kidney. The present study investigated the roles for SPARC in vascular endothelial cell dysfunction and inflammation in the setting of hypertension. Design and method: Rats were treated with deoxycorticosterone acetate (DOCA) and 1% salt water for 0, 1, 2 or 3 weeks. Blood pressure was measured by tail-cuff methods, and thoracic aorta was isolated to examine acetylcholine-induced vasodilatory response, macrophage infiltration by immunohistochemistry, and protein expression of SPARC and ADAMTS1 by Western blotting. In the separate experiment, angiotensin II (10–7mol/L, 6hr) or SPARC recombinant protein (100nmol/L, 24hr) was treated to cultured rat aortic endothelial cells (RAECs) with/without siRNA targeting SPARC and ADAMTS1. MCP-1 and LOX-1 mRNA levels were measured by real-time RT-PCR. Result: DOCA-salt caused time-dependent increases in systolic blood pressure, impairment of endothelium-dependent vasodilation, and macrophage infiltration into the adventitial area of the aorta. The expression of SPARC in the DOCA-salt rat aorta was enhanced at week1 and week2 compared to week0. ADAMTS1 expression tended to increase from week1 and showed significant increases at week3. In RAECs, SPARC and ADAMTS1 gene knockdown aggravated angiotensin II-induced overexpression of LOX-1 and MCP-1 mRNA, indicating anti-inflammatory effects of SPARC. On the other hand, SPARC recombinant protein treatment induced the upregulation of LOX-1 and MCP-1. Conclusions: SPARC may be induced at the early stage of vascular injury to compensate inflammation under the existence of angiotensin II. We need further investigation into the diverse effects of SPARC and the relationship between SPARC and ADAMTS1.

Genetic Expression between Ageing and Exercise: Secreted Protein Acidic and Rich in Cysteine as a Potential "Exercise Substitute" Antiageing Therapy.

Ageing is the effect of time on biological entities. It represents a risk factor for a variety of diseases and health disorders; thus, therapeutic options are required to tackle ageing issues. Modern geriatric medicine prescribes exercise to counteract ageing effects. This work presents secreted protein acidic and rich in cysteine (SPARC) as a potential antiageing therapy. Indeed, SPARC declines with ageing, exercise induces SPARC, and SPARC overexpression in mice mimics exercise. Thus, we hypothesize that SPARC is an exercise-induced factor that is beyond—at least part of—the antiageing effects induced by exercise. This could become a potential antiageing therapy for the elderly that counteracts ageing by mimicking the effects of exercise without needing to perform exercise. This is of particular importance because ageing usually reduces mobility and age-related diseases can reduce the ability to perform the required physical activity. On the other hand, the possibilities of mimicking exercise benefits via SPARC are not limited to ageing, and can be applied in various contexts in which exercise cannot be performed because of physical disabilities, health disorders, or limited mobility.

SPARC Induces E-Cadherin Repression and Enhances Cell Migration through Integrin αvβ3 and the Transcription Factor ZEB1 in Prostate Cancer Cells

Secreted protein acidic and rich in cysteine (SPARC), or osteonectin, is a matricellular protein that modulates interactions between cells and their microenvironment. SPARC is expressed during extracellular matrix remodeling and is abundant in bone marrow and high-grade prostate cancer (PCa). In PCa, SPARC induces changes associated with epithelial–mesenchymal transition (EMT), enhancing migration and invasion and increasing the expression of EMT transcriptional factor Zinc finger E-box-binding homeobox 1 (ZEB1), but not Zinc finger protein SNAI1 (Snail) or Zinc finger protein SNAI2 (Slug). It is unknown whether the SPARC-induced downregulation of E-cadherin in PCa cells depends on ZEB1. Several integrins are mediators of SPARC effects in cancer cells. Because integrin signaling can induce EMT programs, we hypothesize that SPARC induces E-cadherin repression through the activation of integrins and ZEB1. Through stable knockdown and the overexpression of SPARC in PCa cells, we demonstrate that SPARC downregulates E-cadherin and increases vimentin, ZEB1, and integrin β3 expression. Knocking down SPARC in PCa cells decreases the tyrosine-925 phosphorylation of FAK and impairs focal adhesion formation. Blocking integrin αvβ3 and silencing ZEB1 revert both the SPARC-induced downregulation of E-cadherin and cell migration enhancement. We conclude that SPARC induces E-cadherin repression and enhances PCa cell migration through the integrin αvβ3/ZEB1 signaling pathway.

Secreted Protein Acidic and Rich in Cysteine (Sparc) KO Leads to an Accelerated Ageing Phenotype Which Is Improved by Exercise Whereas SPARC Overexpression Mimics Exercise Effects in Mice.

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein implicated in various functions, including metabolism, tissue regeneration, and functional homeostasis. SPARC/Sparc declines with ageing but increases with exercise. We aim to verify two hypotheses: (1) SPARC deficiency leads to an ageing-like phenotype (metabolic decline, muscle loss, etc.), and (2) SPARC overexpression would mimic exercise, counteract ageing, and improve age-related changes. Our mice experiments are divided into two parts. First, we explore the consequences of Sparc knockout (KO) and compare them to the ageing effects. We also observe the effects of exercise. In the second part, we study the effects of SPARC overexpression and compare them to the exercise benefits. At the end, we make an analysis of the results to point out the analogies between Sparc KO and the ageing-like phenotype on the one hand and make comparisons between SPARC overexpression and exercise in the context of exercise counteracting ageing. The measurements were mainly related to tissue weights, adiposity, metabolism, and muscle strength. The main findings are that Sparc KO reduced glucose tolerance, muscle glucose transporter expression, and abdominal adipose tissue weight but increased glycogen content in the muscle. SPARC overexpression increased muscle strength, muscle mass, and expressions of the muscle glucose transporter and mitochondrial oxidative phosphorylation but lowered the glycemia and the adiposity, especially in males. Collectively, these findings, and the data we have previously reported, show that Sparc KO mice manifest an ageing-like phenotype, whereas SPARC overexpression and exercise generate similar benefits. The benefits are towards counteracting both the SPARC deficiency-induced ageing-like phenotype as well as reversing the age-related changes. The potential applications of these findings are to build/optimize Sparc KO-based animal models of various health conditions and, on the other hand, to develop therapies based on introducing SPARC or targeting SPARC-related pathways to mimic exercise against age-related and metabolic disorders.

Methylation-mediated expression of SPARC is correlated with tumor progression and poor prognosis of breast cancer

Secreted protein acidic and rich in cysteine (SPARC) plays a crucial role in the formation and progression of tumors. DNA methylation has become increasingly recognized as a frequent event of epigenetic alterations and one of the primary mechanisms of gene inactivation. The study aims to investigate the status of DNA methylation and the biofunction of SPARC in breast cancer. The qRT-PCR, BGS, and MSP methods were respectively employed to measure the relative mRNA expression levels and methylation status of SPARC. Additionally, the effects of SPARC on cell proliferation, migration, and invasion were examined in SPARC overexpression and knockdown cells. Immunohistochemical staining and western blot assay were used to examine the protein expression of genes. The expression levels of SPARC were found to be higher in breast cancer tissues and most breast cancer cells. The expression levels of SPARC in MDA-MB-231 and MCF-7 cells were significantly reversed by 5-Aza-dC treatment. Furthermore, the high expression and promoter DNA hypomethylation of SPARC were detected in triple-negative breast cancer tissues, while no expression changes of SPARC were found in luminal A breast cancer tissues. Overexpression of SPARC dramatically promoted MCF-7 cells migration and invasion, while knockdown of SPARC inhibited MDA-MB-231 cells migration and invasion. SPARC was involved in the epithelial-mesenchymal transition (EMT) process of breast cancer cells. The expression levels of mesenchymal markers N-cadherin, Vimentin, and β-catenin were upregulated, while E-cadherin was downregulated in SPARC overexpressed breast cancer cells. Conversely, the expression levels of EMT-related genes demonstrated the opposite trend in SPARC knockdown cells. To conclude, high expression of SPARC regulated by promoter hypomethylation promotes breast cancer cells migration and invasion, thus SPARC may act as an oncogene and serve as a potential target for breast cancer therapy.

MiR-211-5p Inhibits the Biological Behaviors of Colorectal Cancer via SPARC-Related Growth Factor Pathways.

Colorectal cancer (CRC) is a highly malignant cancer with poor prognosis. MiR-211-5p has been widely studied as an antioncogene; however, its function and mechanism in CRC are still unknown. This study aimed to investigate the expression patterns and biological implications of miR-211-5p in CRC. This study used quantitative real-time polymerase chain reaction to evaluate miR-211-5p expression in CRC cells and tissues. MiR-211-5p mimics were constructed to overexpress miR-211-5p in Lovo and SW480 cells. Tumor bioactivities of CRC, including cell proliferation, migration, invasion, and colony formation, were evaluated. The dual-luciferase assay was used to confirm the targeted relationship between miR-211-5p expression and secreted protein acidic and rich in cysteine (SPARC). In addition, Western blot analysis and immunohistochemical staining were used to measure SPARC, platelet-derived growth factor (PDGF), transforming growth factor β (TGF-β), and vascular endothelial growth factor (VEGF) expression levels. This study showed downregulated miR-211-5p expression in CRC cells and tissues, and this downregulation correlated with CRC progression. Meanwhile, miR-211-5p restrained CRC cell proliferation, colony formation, migration, and invasion. Mechanistically, SPARC-related growth factor pathways, including VEGF, PDGF, and TGF-β pathways, were upregulated in CRC tissues. Furthermore, SPARC acted as the target gene for miR-211-5p. Finally, SPARC overexpression suppressed the inhibitory effect of miR-211-5p on CRC cell progression. MiR-211-5p suppressed the invasion, migration, proliferation, and progression of CRC cells through sponging SPARC-related growth factor 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 regulates ferroptosis induced by sorafenib in human hepatocellular carcinoma.

Secreted protein acidic and rich in cysteine (SPARC) is implicated in cancer progression, but its role and associated molecular mechanism in the sorafenib sensitivity of hepatocellular carcinoma cells (HCC) remains elusive. Human HCC cell lines Hep3B and HepG2 were treated with sorafenib alone or combined with activator or inhibitor of ferroptosis. Cell viability assay, reactive oxygen species (ROS) assay, lactate dehydrogenase (LDH) assay and western blot were used to study the regulatory mechanism of SPARC on HCC cells. Overexpression of SPARC enhanced the cytotoxic effect of sorafenib in Hep3B and HepG2 cells compared with parental cells. Depletion of SPARC decreased the cytotoxic effect of sorafenib in Hep3B and HepG2 cells compared with parental cells. Moreover, overexpression of SPARC significantly induced LDH release, whereas depletion of SPARC suppressed the release of LDH in Hep3B and HepG2 cells. Inhibition of ferroptosis exerted a clear inhibitory role against LDH release, whereas activation of ferroptosis promoted the release of LDH in HCC cells, as accompanied with deregulated expression of ferroptosis-related proteins. Furthermore, overexpression of SPARC induced oxidative stress, whereas depletion of SPARC suppressed the production of ROS. Deferoxamine (DFX)-induced inhibition of ferroptosis suppressed the production of ROS, while activation of ferroptosis promoted the contents of ROS in HCC cells exposed to sorafenib. Our findings give a better understanding of ferroptosis and its molecular mechanism in HCC cells that is regulated by SPARC in response to sorafenib.

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.

Epithelial and fibroblast SPARC expression patterns in oral leukoplakia and oral squamous cell carcinoma

This study evaluated and compared the expression of secreted protein acidic and rich in cysteine (SPARC) in epithelial cells and fibroblasts of oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) using normal oral mucosa as a control. The expression of SPARC was determined in samples of normal oral mucosa (n=12), OL without dysplasia (n=31), OL with dysplasia (n=54), and OSCC (n=69) using immunohistochemistry. The percentage of positive cells in epithelial cells and fibroblasts was independently evaluated. Epithelial SPARC was found in 33.3%, 35.5%, 25.9%, and 66.7% of normal oral mucosa, OL without dysplasia, OL with dysplasia, and OSCC, respectively. Fibroblast SPARC was found in 50.0%, 29.0%, 46.3%, and 84.1% of normal oral mucosa, OL without dysplasia, OL with dysplasia, and OSCC, respectively. OSCC had higher epithelial and fibroblast SPARC expression than normal oral mucosa, OL without dysplasia, and OL with dysplasia (P < .05). No significant differences were observed in epithelial and fibroblast SPARC among normal oral mucosa or OL with and without dysplasia. Overexpression of epithelial and fibroblast SPARC was observed in OSCC but not in OL, suggesting that SPARC is involved in the late stage of oral carcinogenesis.

Bioresponsive micro-to-nano albumin-based systems for targeted drug delivery against complex fungal infections

As a typical human pathogenic fungus, Cryptococcus neoformans is a life-threatening invasive fungal pathogen with a worldwide distribution causing ∼700,000 deaths annually. Cryptococcosis is not just an infection with multi-organ involvement, intracellular survival and extracellular multiplication of the fungus also play important roles in the pathogenesis of C. neoformans infections. Because adequate accumulation of drugs at target organs and cells is still difficult to achieve, an effective delivery strategy is desperately required to treat these infections. Here, we report a bioresponsive micro-to-nano (MTN) system that effectively clears the C. neoformans in vivo. This strategy is based on our in-depth study of the overexpression of matrix metalloproteinase 3 (MMP-3) in infectious microenvironments (IMEs) and secreted protein acidic and rich in cysteine (SPARC) in several associated target cells. In this MTN system, bovine serum albumin (BSA, a natural ligand of SPARC) was used for the preparation of nanoparticles (NPs), and then microspheres were constructed by conjugation with a special linker, which mainly consisted of a BSA-binding peptide and an MMP-3-responsive peptide. This MTN system was mechanically captured by the smallest capillaries of the lungs after intravenous injection, and then hydrolyzed into BSA NPs by MMP-3 in the IMEs. The NPs further targeted the lung tissue, brain and infected macrophages based on the overexpression of SPARC, reaching multiple targets and achieving efficient treatment. We have developed a size-tunable strategy where microspheres “shrink” to NPs in IMEs, which effectively combines active and passive targeting and may be especially powerful in the fight against complex fungal infections.

Intestinal production of secreted protein acidic and rich in cysteine (SPARC) in patients with ulcerative colitis

BackgroundUlcerative colitis (UC) is an inflammatory disease of the intestine. The genetics factors play an important role in the pathogenesis of UC. SPARC exacerbates colonic inflammatory symptoms in dextran sodium sulphate-induced murine colitis. The aim of the study was to measure the gene expression and intestinal production of SPARC in patients with UC and controls as well as, to determine its correlation with histological activity. MethodsWe included 40 patients with confirmed diagnosis of UC, and 20 controls without endoscopic evidence of any type of colitis or neoplasia. The relative quantification of the gene expression was performed by real time PCR. GAPDH was used as housekeeping gene for normalization purposes and quality controls. Protein expression was determined by immunohistochemistry. ResultsThe gene expression of SPARC was increased in patients with active UC vs in remission UC and vs. controls (P = 0.005). There was no significant difference between patients with remission UC and controls. The overexpression of SPARC in patients with active UC correlated significantly with mild histological activity (P = 0.06, OR = 7.77, IC = 0.77–77.9) moderate (P = 0.06, OR = 8.1, IC 95%=0.79–82.73), and severe (P = 0.03, OR = 6.5, IC 95%=1.09–38.6). Double positive SPARC+/CD16+ cells were localized mainly in submucosa, muscular layer, and adventitia, and in perivascular inflammatory infiltrates in patients with active UC. ConclusionThe gene and protein expression of SPARC is increased in active UC. SPARC could be a marker of intestinal inflammation and its expression correlates with histological activity.

SPARC enhances 5-FU chemosensitivity in gastric cancer by modulating epithelial-mesenchymal transition and apoptosis

Previous studies have shown that secreted protein acidic and rich in cysteine (SPARC) proteins can inhibit the development of cancer cells in various ways, such as by inhibiting angiogenesis and inhibiting cell proliferation. In fact, SPARC proteins may have an effect on the chemoresistance of gastric cancer cells to 5-Fluorouracil (5-FU), which needs further research in the future. Therefore, the purpose of this study was to explore the relationship between SPARC proteins and the chemosensitivity of gastric cancer cells to 5-FU. In vitro, after SPARC protein levels were regulated by plasmid, siRNA and human recombinant SPARC protein transfection in MGC-803, SGC-7901 and BGC-823 cells, we detected epithelial-mesenchymal transition (EMT), apoptosis markers and cell viability after 5-FU treatment. In vivo, we implanted BGC-823 cells with stable SPARC overexpression into nude mice. Tumour size was measured to assess the effect of SPARC protein on tumour formation and 5-FU chemosensitivity. In SGC-7901 and BGC-823 cells, both endogenous and exogenous upregulation of SPARC protein levels decreased cell viability, destroyed cytoskeletal F-actin, inhibited cell migration, and downregulated a series of transcription factors to inhibit cell EMT; it also upregulated cell apoptosis-related proteins to promote cell apoptosis. However, we obtained opposite results in SPARC knockdown MGC-803 cells. In vivo, compared with the control group, the group engrafted with BGC-823 cells stably overexpressing SPARC had a significant smaller tumour size. After 5-FU treatment, the new tumour gradually decreased in size. Our results show that the SPARC protein could enhance 5-FU chemosensitivity in gastric cancer cell lines by inhibiting EMT and promoting cell apoptosis.

MiR-29c-3p inhibits epithelial-mesenchymal transition to inhibit the proliferation, invasion and metastasis of cervical cancer cells by targeting SPARC.

BackgroundCervical cancer is one of the most common gynecological malignancies. Cancer recurrence and the poor efficacy of cervical cancer treatments are mainly caused by invasion and metastasis of cervical cancer cells. This study is to investigate whether miR-29c-3p can inhibit epithelial-mesenchymal transition (EMT) by targeting secreted protein acidic and rich in cysteine (SPARC), thus inhibiting the invasion and metastasis of human cervical cancer cells.MethodsThe expression levels of miR-29c-3p and SPARC in cervical cancer tissues and non-tumor adjacent tissues, human normal cervical epithelial cell line Ect1/E6E7 and human cervical cancer cell lines HeLa, CaSki, C-33A, HT-3 and SiHa were detected. After the expression of miR-29c-3p and SPARC was intervened in C-33A and SiHa cells, RT-qPCR was used to detect the expression levels of miR-29c-3p and SPARC. Western blot was performed to observe the expression levels of SPARC and EMT-related proteins. The proliferation rate of C-33A and SiHa cells was measured using an MTT assay. The viability of the cells was determined using a cell colony formation assay. Apoptosis and cell cycle was measured using flow cytometry, and migration ability was observed using a wound healing assay. A transwell invasion assay was used to determine the invasion ability of the cells, whilst a dual-luciferase reporter assay verified that SPARC was a target gene of miR-29c-3p.ResultsmiR-29c-3p was expressed at low levels in cervical cancer tissues and cells, while SPARC expression was upregulated. The luciferase reporter assay confirmed that miR-29c-3p targeted and bound to SPARC. MiR-29c-3p overexpression significantly inhibited the proliferation, invasion, migration, and cell cycle of cervical cancer cells, but promoted apoptosis. In the miR-29c-3p group (miR-29c-3p overexpression), EMT progression was inhibited by upregulating E-cadherin expression and downregulating N-cadherin, vimentin, and Snail expression, which was contrary to the results of the in-miR-29c-3p group (inhibition of miR-29c-3p expression). In the miR-29c-3p + SPARC group (miR-29c-3p overexpression + SPARC overexpression), the effect of miR-29c-3p overexpression on cervical cancer cell functions was reversed.ConclusionsmiR-29c-3p can inhibit EMT by targeting SPARC, so as to inhibit the invasion and metastasis of cervical cancer cells.

SPARC Negatively Correlates With Prognosis After Transarterial Chemoembolization and Facilitates Proliferation and Metastasis of Hepatocellular Carcinoma via ERK/MMP Signaling Pathways.

Background: Transarterial chemoembolization (TACE) represents a widely accepted treatment procedure for intermediate stage or unresectable hepatocellular carcinoma (HCC). However, few studies have evaluated serologic prognosis factors in patients with HCC before TACE. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein affecting tumorigenesis and metastasis, and leading to poor prognosis in HCC. Therefore, to further explore the potential prognosis value of SPARC, the expression levels in the plasma of patients and its potential molecular mechanisms underlying the regulation of HCC were investigated in this study.Materials and Methods: The study population included 43 patients with HCC who underwent TACE. To evaluate the expression of SPARC in different grades of pathological tissues, the immunohistochemistry was performed on tissues from 89 patients with HCC. Lentiviral vectors carrying interference sequences, as well as vectors harboring the complete open reading frame of SPARC for the knockdown or overexpression of SPARC in HuH-7 or HepG2 cells, respectively, allowed us to determine the biological functions of SPARC in vitro and in vivo. We also evaluated the levels of phosphorylated extracellular signal-regulated kinases 1/2 (p-ERK1/2) and matrix metalloproteinases 2/9 (MMP2/9) activation.Results: The association between serum levels of SPARC and the survival at different TNM and Barcelona-Clinic Liver Cancer (BCLC) stages in patients with HCC undergoing TACE were evaluated. We observed a significant upregulation of SPARC in high grade HCC tissues, predicting unfavorable prognosis, and suggesting an important tumor-promoting effect of SPARC. Functional studies indicated that downregulation of SPARC contributed to the inhibition of proliferation and metastasis of HuH-7 cells in vitro, whereas its overexpression led to opposite phenotypes. Mechanistically, decreased expression of SPARC resulted in dephosphorylation of ERK1/2 and deactivation of MMP2/9, thereby inhibiting growth and metastasis of HCC. Importantly, low expression levels of SPARC inhibited the formation of subcutaneous tumors in nude mice.Conclusions: SPARC was found to facilitate proliferation and metastasis of HCC via modulation of the ERK1/2-MMP2/9 signaling pathways. Our research has provided a glimpse on the biological mechanism of SPARC and might contribute to the eventual treatment of liver cancer.

Macrophage-derived SPARC Attenuates M2-mediated Pro-tumour Phenotypes.

Since the theory of seed and soil was put forward, people have increasingly recognized that the tumour microenvironment is an important regulator of tumour progression and therapeutic response. Among them, M2-type macrophages (M2, as the major macrophage subtype in the tumour foci) have important promoting effects on various biological behaviours. Secreted protein acidic and rich in cysteine (SPARC) is an important anti-tumour component in the microenvironment of gastric cancer. This study shows that macrophages are an important source of the SPARC and that SPARC overexpression in M2 can reduce M2-mediated promoting proliferation, migration and anti-apoptotic effects in gastric cancer. Additionally, the AKT/mTOR signalling pathways may participate in the malignant process.

Prognostic role of secreted protein acidic and rich in cysteine in patients with solid tumors

Objectives:To analyze the heterogeneous functions of secreted protein acidic and rich in cysteine (SPARC) from different origins and in different tumor microenvironments with the purpose of determining its clinical significance.Methods:The PubMed, CINAHL, Cochrane, Web of Science and Embase databases were utilized. Studies that focused on the effects of SPARC expression on solid tumor progression and clinical implications were used. The different outcomes including overall survival and disease-free survival were analyzed to evaluate their relations with tumor- and stroma-derived SPARC expression.Results:A total of 26 studies including 5,939 patients were enrolled in the present meta-analysis. Tumor-derived SPARC overexpression was significantly related with poor overall survival (hazard ratio: 1.478; 95% CI: 1.143-1.910; p=0.003), and a similar tendency was also observed in disease-free survival (hazard ratio: 1.476; 95% CI: 0.993-2.195; p=0.054). However, the hazard ratios for overall survival and disease-free survival did not present a statistical trend in stromal SPARC overexpression. Tumor type subgroup analysis revealed marked heterogeneity among outcomes. In pancreatic cancer, SPARC overexpression in the stroma was significantly associated with poorer overall survival and disease-free survival. In colorectal cancer, SPARC overexpression in the stroma was associated with better disease-free survival.Conclusion:For the majority of solid tumors, SPARC in cancer cells may be an unfavorable indicator for long-term survival for patients. As for stromal expression, SPARC indicates a poorer prognosis in pancreatic cancer, but a better disease-free survival in colorectal cancer. Secreted protein acidic and rich in cysteine might be a potential biomarker for solid tumor prognosis.