IGF-I and IGFBP-3 augment transforming growth factor-beta actions in human renal carcinoma cells

Cyclovirobuxine inhibits the progression of clear cell renal cell carcinoma by suppressing the IGFBP3-AKT/STAT3/MAPK-Snail signalling pathway

Of all pathological types of renal cell cancer (RCC), clear cell renal cell carcinoma (ccRCC) has the highest incidence. Cyclovirobuxine (CVB), a triterpenoid alkaloid isolated from Buxus microphylla, exhibits antitumour activity against gastric cancer and breast cancer; however, the mechanism by which CVB inhibits ccRCC remains unclear. The aim of our study was to explore the antitumour effects of CVB on ccRCC and to elucidate its exact mechanism. Cell viability, proliferation, cell cycle distribution, apoptosis, wound healing and invasion were evaluated. Furthermore, Western blotting, immunofluorescence staining, immunohistochemical staining, and bioinformatics analyses were utilized to comprehensively probe the molecular mechanisms. The in vivo curative effect of CVB was explored using a 786-O xenograft model established in nude mice. CVB reduced cell viability, proliferation, angiogenesis, the epithelial-mesenchymal transition (EMT), migration and invasion. In addition, CVB induced cell cycle arrest in S phase and promoted apoptosis. The expression of the EMT-related transcription factor Snail was significantly downregulated by CVB via the inhibition of the AKT, STAT3 and MAPK pathways. We revealed that insulin-like growth factor binding protein 3 (IGFBP3) was the true therapeutic target of CVB. CVB exerted anti-ccRCC effects by blocking the IGFBP3-AKT/STAT3/MAPK-Snail pathway. Targeted inhibition of IGFBP3 with CVB treatment may become a promising therapeutic regimen for ccRCC.

SMAD2 promotes myogenin expression and terminal myogenic differentiation

SMAD2 is a transcription factor, the activity of which is regulated by members of the transforming growth factor β (TGFβ) superfamily. Although activation of SMAD2 and SMAD3 downstream of TGFβ or myostatin signaling is known to inhibit myogenesis, we found that SMAD2 in the absence of TGFβ signaling promotes terminal myogenic differentiation. We found that, during myogenic differentiation, SMAD2 expression is induced. Knockout of SMAD2 expression in primary myoblasts did not affect the efficiency of myogenic differentiation but produced smaller myotubes with reduced expression of the terminal differentiation marker myogenin. Conversely, overexpression of SMAD2 stimulated myogenin expression, and enhanced both differentiation and fusion, and these effects were independent of classical activation by the TGFβ receptor complex. Loss of Smad2 in muscle satellite cells in vivo resulted in decreased muscle fiber caliber and impaired regeneration after acute injury. Taken together, we demonstrate that SMAD2 is an important positive regulator of myogenic differentiation, in part through the regulation of Myog.

The Genes-Candidates for Prognostic Markers of Metastasis by Expression Level in Clear Cell Renal Cell Cancer

The molecular prognostic markers of metastasis are important for personalized approaches to clear cell renal cell carcinoma (ccRCC) treatment but markers for practical use are still missing. To address this gap we studied the expression of ten genes—CA9, NDUFA4L2, VWF, IGFBP3, BHLHE41, EGLN3, SAA1, CSF1R, C1QA, and FN1—through RT-PCR, in 56 ccRCC patients without metastases and with metastases. All of these, excluding CSF1R, showed differential and increased (besides SAA1) expression in non-metastasis tumors. The gene expression levels in metastasis tumors were decreased, besides CSF1R, FN1 (not changed), and SAA1 (increased). There were significant associations of the differentially expressed genes with ccRCC metastasis by ROC analysis and the Fisher exact test. The association of the NDUFA4L2, VWF, EGLN3, SAA1, and C1QA expression with ccRCC metastasis is shown for the first time. The CA9, NDUFA4L2, BHLHE4, and EGLN3 were distinguished as the strongest candidates for ccRCC metastasis biomarkers. We used an approach that presupposed that the metastasis marker was the expression levels of any three genes from the selected panel and received sensitivity (88%) and specificity (73%) levels with a relative risk of RR > 3. In conclusion, a panel of selected genes—the candidates in biomarkers of ccRCC metastasis—was created for the first time. The results might shed some light on the ccRCC metastasis processes.

NDUFA4L2 is associated with clear cell renal cell carcinoma malignancy and is regulated by ELK1

Background

Clear cell renal cell carcinoma (ccRCC) is the most common and lethal cancer of the adult kidney. However, its pathogenesis has not been fully understood till now, which hinders the therapeutic development of ccRCC. NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 (NDUFA4L2) was found to be upregulated and play an important role in ccRCC. We aimed to further investigate the underlying mechanisms by which NDUFA4L2 exerted function and its expression level was upregulated.

Methods

The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) data were mined to verify the change of NDUFA4L2 expression level in ccRCC tissues. The correlation between expression level of NDUFA4L2 and cell proliferation/apoptosis was explored by Gene Set Enrichment Analysis (GSEA). Protein-protein interaction (PPI) network of NDUFA4L2 was constructed. Biological process and involved pathways of NDUFA4L2 were analyzed by gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. The transcription factors (TFs) which can induce the expression of NDUFA4L2 were explored in clinical samples by correlation analysis and its regulation on the expression of NDUFA4L2 was verified by knockdown experiment.

Results

NDUFA4L2 was verified to be overexpressed in ccRCC tissues and its expression level was increased accordingly as the American Joint Committee on Cancer (AJCC) stage progressed. A high NDUFA4L2 level predicted the poor prognosis of ccRCC patients and correlated with enhanced cell proliferation and anti-apoptosis. NDUFA4L2 may interact with 14 tumor-related proteins, participate in growth and death processes and be involved in ccRCC-related pathways, such as insulin-like growth factor 1 (IGF-1), mammalian target of Rapamycin (mTOR) and phosphoinositide 3 kinase serine/threonine protein kinase (PI3K/AKT). ETS domain-containing protein ELK1 level positively correlated with the level of NDUFA4L2 in ccRCC tissues and ELK1 could regulate the expression of NDUFA4L2 in ccRCC cells.

Discussion

NDUFA4L2 upregulation was associated with ccRCC malignancy. NDUFA4L2 expression was regulated by ELK1 in ccRCC cells. Our study provided potential mechanisms by which NDUFA4L2 affected ccRCC occurrence and progression.

Anti-angiogenic activity of water extract from Euphorbia pekinensis Rupr

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia pekinensis Rupr. (EP) is a Euphorbia species of Euphorbiaceae, which is widely used in traditional Chinese medicine. It has been reported to exhibit therapeutic effects on solid tumors, leukemias, and malignant ascites although underlying molecular mechanisms are poorly delineated. Anti-angiogenic therapy is a recognized strategy for treating cancer-based solid tumors, and is also associated with malignant ascites treatment.

STUDY AIM

To study the anti-angiogenic properties of the water extract of EP vinegar preparation (WEVEP).

MATERIALS AND METHODS

Following WEVEP treatment, intersegmental blood vessels were assessed during the development of transgenic Tg (flk: mCherry) zebrafish as was the proliferation, migration and network formation of HUVECs in vitro. mRNA expression of specific angiogenic-related genes including VEGF family members, Met, and NRP2 was also measured using quantitative real-time PCR (Q-PCR).

RESULTS

Data demonstrated that angiogenesis was inhibited by the WEVEP in zebrafish (from 100µg/mL to 250µg/mL, p < 0.0001) and in the HUVEC model (from 100µg/mL to 400µg/mL, p < 0.0001). In the zebrafish model, the mean vessel numbers of administered groups were 26.00 ± 1.29 (100µg/mL), 24.54 ± 2.20 (150µg/mL), 22.66 ± 2.68 (200µg/mL), 20.80 ± 1.75 (250µg/mL), compared to 27.67 ± 0.96 of control group. Relative quantitative gene expression in zebrafish treated with WEVEP demonstrated that only VEGFR3 was significantly increased and other 23 genes including Met, VEGFA, Flt-1 were significantly decreased.

CONCLUSION

WEVEP can positively modulate angiogenesis via multiple targeting mechanisms. Our novel results contribute towards the discovery of a possible mechanism(s) of the traditional use of EP in the treatment of cancer and malignant ascites.

Complement component 1, q subcomponent binding protein (C1QBP) in lipid rafts mediates hepatic metastasis of pancreatic cancer by regulating IGF-1/IGF-1R signaling

Pancreatic cancer shows a remarkable predilection for hepatic metastasis. Complement component 1, q subcomponent binding protein (C1QBP) can mediate growth factor-induced cancer cell chemotaxis and distant metastasis by activation of receptor tyrosine kinases. Coincidentally, insulin-like growth factor-1 (IGF-1) derived from the liver and cancer cells itself has been recognized as a critical inducer of hepatic metastasis. However, the mechanism underlying IGF-1-dependent hepatic metastasis of pancreatic cancer, in which C1QBP may be involved, remains unknown. In the study, we demonstrated a significant association between C1QBP expression and hepatic metastasis in patients with pancreatic cancer. IGF-1 induced the translocation of C1QBP from cytoplasm to lipid rafts and further drove the formation of CD44 variant 6 (CD44v6)/C1QBP complex in pancreatic cancer cells. C1QBP interacting with CD44v6 in lipid rafts promoted phosphorylation of IGF-1R and thus activated downstream PI3K and MAPK signaling pathways which mediated metastatic potential of pancreatic cancer cells including proliferation, apoptosis, invasion, adhesion and energy metabolism. Furthermore, C1QBP knockdown suppressed hepatic metastasis of pancreatic cancer cells in nude mice. We therefore conclude that C1QBP in lipid rafts serves a key regulator of IGF-1/IGF-1R-induced hepatic metastasis from pancreatic cancer. Our findings about C1QBP in lipid rafts provide a novel strategy to block IGF-1/IGF-1R signaling in pancreatic cancer and a reliable premise for more efficient combined modality therapies.

Insulin-like growth factor-1 signaling in renal cell carcinoma

Renal cell carcinoma (RCC) incidence is highest in highly developed countries and it is the seventh most common neoplasm diagnosed. RCC management include nephrectomy and targeted therapies. Type 1 insulin-like growth factor (IGF-1) pathway plays an important role in cell proliferation and apoptosis resistance. IGF-1 and insulin share overlapping downstream signaling pathways in normal and cancer cells. IGF-1 receptor (IGF1R) stimulation may promote malignant transformation promoting cell proliferation, dedifferentiation and inhibiting apoptosis. Clear cell renal cell carcinoma (ccRCC) patients with IGF1R overexpression have 70 % increased risk of death compared to patients who had tumors without IGF1R expression. IGF1R signaling deregulation may results in p53, WT, BRCA1, VHL loss of function. RCC cells with high expression of IGF1R are more resistant to chemotherapy than cells with low expression. Silencing of IGF1R increase the chemosensitivity of ccRCC cells and the effect is greater in VHL mutated cells. Understanding the role of IGF-1 signaling pathway in RCC may result in development of new targeted therapeutic interventions. First preclinical attempts with anti-IGF-1R monoclonal antibodies or fragment antigen-binding (Fab) fragments alone or in combination with an mTOR inhibitor were shown to inhibit in vitro growth and reduced the number of colonies formed by of RCC cells.

The joint effects of arsenic and risk diplotypes of insulin-like growth factor binding protein-3 in renal cell carcinoma

The association between renal cell carcinoma (RCC) and diabetes mellitus (DM), alcohol consumption, insulin-like growth factor binding protein-3 (IGFBP-3) gene, and arsenic exposure, has been the subject of independent studies. However, few studies have examined the combined effect of these factors on RCC risk. The aim of this study was to examine the association between these risk factors and the odds ratio (OR) of RCC. A hospital-based case-control study was conducted in 398 RCC patients and 756 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of IRS-1 (Gly972Arg), PI3-K (Met362Ile), IGFBP-3 (A[-202]C), and IGFBP-3 (C[-1590]A) by PCR-RFLP. Profiles of urinary arsenic were measured by high performance liquid chromatography linked with hydride generator and atomic absorption spectrometry. Participants who had never consumed alcohol and who had high total levels of urinary arsenic and DM had a high OR of RCC. IGFBP-3 (A[-202]C) and IGFBP-3 (C[-1590]A) were in linkage disequilibrium. Participants carrying high-risk IGFBP-3 diplotypes A-C/C-C, A-A/A-C, and C-A/C-A had a significantly higher odds ratio (OR) and 95% confidence interval (2.80, 1.91-4.12) of RCC compared to those carrying other IGFBP-3 diplotypes. This is the first study to show that borderline significant interaction of high total levels of urinary arsenic and IGFBP-3 high-risk diplotypes significantly enhanced the OR of RCC. Our data also provide evidence that subjects with more risk factors (e.g., high total levels of urinary arsenic, never consumed alcohol, IGFBP-3 high-risk diplotypes) may experience a higher OR of RCC.

Insulin and IGFs in renal cancer risk and progression

Insulin and IGFs play a significant role in cancer development and progression, including renal cell carcinoma (RCC). RCC is the most frequent type of kidney cancer in adults and the tenth most common malignancy worldwide. Insulin is normally associated with metabolism control, whereas IGFs are defined as proliferation regulators. Today, there is convincing evidence of an association between obesity and the risk of RCC. Indicated risk factors together with type 2 diabetes are irreversibly connected with circulating insulin and IGF levels. The interplay between these molecules, their receptors, and IGF-binding proteins might be crucial for RCC cell biology and RCC progression. Given the potent activity IGF/IGF receptor 1 (IGF1R) inhibitors demonstrate against RCC in basic research, some type of combination therapy may prove to be beneficial clinically in the management of RCC. This review addresses not only molecular but also clinical associations between insulin and IGF1 signaling pathways and both RCC biology and clinical course. Revealing these interactions may improve our understanding of basic molecular oncology processes in RCC and improve treatment strategies.

Priming hMSCs with a putative anti-cancer compound, myrtucommulone-a: a way to harness hMSC cytokine expression via modulating PI3K/Akt pathway?

Tumour microenvironment is a key factor for cancer growth and metastasis. Tumour surrounding tissue is known to include high number of mesenchymal stem cells which have been thought to have a role in regulating cancer cell behaviour via paracrine signalling. Therefore, modulating human mesenchymal stem cell (hMSC) secretome is highly significant for controlling and treating disease. Since common therapeutic agents are known to enhance cancer resistance, there is a strong urge to define novel agents for developing cell-based therapies. In the present study, we aimed at investigating the effect of active compounds, myrtucommulone-A (MC-A) and thymoquinone (TQ), on hMSC cytokine expression. Our data revealed that MC-A treatment have significantly altered cytokine expression in hMSCs. Upon MC-A treatment, hMSCs decreased the expression levels of various cytokines including TNF-α, VEGF, IL-6, IL-8 and FGF-2. hMSC conditioned medium (CM) primed with MC-A decreased the proliferation, migration ability and clonogenicity of bladder cancer cells and breast cancer cells in comparison to non-primed hMSC medium and hMSC medium primed with TQ. To the best of our knowledge, this study is the first report showing the effects of active compounds, MC-A and TQ, on hMSCs and therefore valuable for highlighting the potential use of active compounds in combination with hMSCs for cell-based targeted cancer therapy.

Pro-angiogenic effects of Carthami Flos whole extract in human microvascular endothelial cells in vitro and in zebrafish in vivo

AIM

Carthami Flos (CF) is a Chinese herb traditionally used for cardiovascular disease and bone injury in China with pharmacological effects on improving blood circulation. The aim of this study was to investigate the angiogenic potential of CF whole extract (extracted by boiling with water, followed by ethanol) and the underlying mechanisms in human microvascular endothelial cells (HMEC-1) in vitro and in transgenic TG(fli1:EGFP)(y1)/+(AB) zebrafish with transgenic endothelial cells expressing EGFP (Enhanced Green Fluorescent Protein) in vivo.

METHODS

Effects of CF whole extract on cell proliferation, migration and tube formation in HMEC-1 cells in vitro were detected by MTT assay, wound healing assay and tube formation assay. Its angiogenic effect in zebrafish was investigated by monitoring the sprout number in the sub-intestinal vessel (SIV), and the underlying mechanisms were tested by quantitative real-time PCR.

RESULTS

CF whole extract increased cell proliferation, migration and tube formation in vitro in HMEC-1 cells. Its angiogenic effect was also confirmed in vivo in zebrafish by increasing the sprout number in the SIV. As determined by quantitative real-time PCR, CF whole extract up-regulated the expression of angiogenesis-related genes in zebrafish, including angiogenic and its associated growth factors and receptors (e.g. IGF1, CTGF, NRP2, and VEGFR3), transcription factor (e.g. HIF1A), matrix degradation and endothelial cell migration-related factors (e.g. MMP2, MMP9, TIMP2, PLG and PLAU), cell adhesion molecules (e.g. ITGAV, ITGB3, beta-catenin and PECAM1), tubule formation factors (e.g. ANGPT1, TIE-2, PDGFR-B, CDH5, S1PR1, FGF2, Shh, and TGFRB1), and blood vessel maturation/formation factor (e.g. Ephrin B2).

CONCLUSIONS

CF whole extract increased angiogenesis in HMEC-1 cells in vitro and in zebrafish in vivo with multiple mechanisms.

Metabolic syndrome and renal cell carcinoma

BACKGROUND

Metabolic syndrome (MS) is a cluster of metabolic abnormalities, which has been regarded as a pivotal risk factor for cardiovascular diseases. Recent studies focusing on the relationship between MS and cancer have recognized the significant role of MS on carcinogenesis. Likewise, growing evidence suggests that MS has a strong association with increased renal cell carcinoma (RCC) risk. This review outlines the link between MS and RCC, and some underlying mechanisms responsible for MS-associated RCC.

MATERIALS AND METHODS

A National Center for Biotechnology Information PubMed search (http://www.pubmed.gov) was conducted using medical subject headings 'metabolic syndrome', 'obesity', 'hypertension', 'diabetes', 'dyslipidemia', and 'renal cell carcinoma'.

RESULTS

This revealed that a variety of molecular mechanisms secondary to MS are involved in RCC formation, progression, and metastasis. A deeper understanding of these molecular mechanisms may provide some strategies for the prevention and treatment of RCC.

CONCLUSIONS

In summary, there is a large body of evidence regarding the link between MS and RCC, within which each component of MS is considered to have a close causal association with RCC.

Insulin-like growth factor binding protein-3 (IGFBP-3) gene variants are associated with renal cell carcinoma

OBJECTIVE

• To evaluate the A to C nucleotide change located 202 bp upstream to the transcription start site, (-202 A/C polymorphism), in the insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) gene, and its association with renal carinogenesis and with clinicopathological characteristics.

PATIENTS AND METHODS

• We matched 158 male patients with clear-cell renal cell carcinoma (CCRCC) to 316 healthy controls, and genotyped one single nucleotide polymorphism (rs2854744) using the polymerase chain reaction restriction fragment length polymorphism technique.

RESULTS

• The alleles and genotypes differed significantly between patients with CCRCC and controls (patients with CCRCC, P= 0.82; controls, P= 0.88). • We found that the frequency of the AA genotype was significantly higher in patients with CCRCC than in controls (odds ratio [OR]= 4.62, 95% confidence interval [CI]= 3.41-7.42, P= 0.001). • The A allele had a gene dose effect in increasing the risk of CCRCC (OR = 4.75, 95% CI = 3.64-7.64, P= 0.001). • The distribution of IGFBP-3 genotypes was also significantly associated with the histological grade (P= 0.001) and clinical stage (P= 0.001).

CONCLUSION

• In the Iranian population, the polymorphism of the IGFBP-3 gene plays a pivotal role in the development of CCRCC.

Obesity and renal cell carcinoma: epidemiology, underlying mechanisms and management considerations

The incidence of both renal cell carcinoma (RCC) and obesity are steadily rising in Western societies. Recent studies have established that obesity is a significant risk factor for the development of several malignancies, including RCC. However, the mechanisms underlying this relationship remain to be fully elucidated. We review herein the epidemiological links between obesity and RCC, the potential mechanisms by which obesity can influence RCC development and progression, and the special considerations related to the treatment of obese patients with RCC.

Investigation of hypoxia and carbonic anhydrase IX expression in a renal cell carcinoma xenograft model with oxygen tension measurements and ¹²⁴I-cG250 PET/CT

OBJECTIVES

In tumors, hypoxia stimulates angiogenesis and correlates with treatment resistance and poor prognosis. We have previously demonstrated hypoxia in human renal cell carcinoma (RCC) via direct oxygen probe measurements. Carbonic anhydrase IX (CA IX) is a protein stimulated by hypoxia and involved in angiogenesis, and is a potential tumor target for imaging and therapies using cG250, a monoclonal antibody that recognizes CAIX. Our objectives were to characterize intratumoral hypoxia in a human RCC xenograft model using oxygen probe measurements; investigate if (124)I-cG250 targets RCC correlating uptake on noninvasive positron emission tomography-computerized tomography (PET-CT) against traditional biodistribution studies, and investigate CAIX expression in this RCC model.

METHODS

BALB/c nude mice had human RCC (SK-RC-52) subcutaneously xenografted with oxygen levels measured by probe. Positron emission tomography (PET/CT) and biodistribution studies ((124)I-cG250) were correlated with oxygen measurements. Immunohistochemistry and autoradiography were performed on selected tumors to confirm CAIX expression.

RESULTS

Oxygen tension in normal tissue (muscle) was 35.08 ± 2.41 mmHg (mean ± 95% CI), significantly greater compared to xenograft SK-RC-52 tumors at 5.02 ± 1.12 mmHg. Biodistribution studies of (124)I-cG250 demonstrated isotope uptake in SK-RC-52 xenografts peaking at 23.45 ± 5.07% ID/g (mean ± SD) 48 hours after antibody injection, which was maintained for a further 2 days (19.43 ± 4.31 and 10.64 ± 5.64 % ID/g, respectively). PET studies demonstrated excellent localization of (124)I-cG250 in tumor, and a significant correlation between SUVmean, SUVmax, and %/ID (124)I-cG250. CAIX expression was present in all groups studied but there was no significant correlation between it and any oxygen parameter studied.

CONCLUSION

Intratumoral hypoxia does exist within a human RCC xenograft model using invasive oxygen probe measurements. (124)I-cG250 targets RCC with correlation between uptake on noninvasive PET-CT studies and traditional biodistribution studies opening the possibility of using PET/CT in future studies. Finally, CAIX expression was not related to hypoxia in this model, supporting the hypothesis that cell lines may subvert known hypoxia mechanisms in hypoxic environments.

An analysis of growth, differentiation and apoptosis genes with risk of renal cancer

We conducted a case-control study of renal cancer (987 cases and 1298 controls) in Central and Eastern Europe and analyzed genomic DNA for 319 tagging single-nucleotide polymorphisms (SNPs) in 21 genes involved in cellular growth, differentiation and apoptosis using an Illumina Oligo Pool All (OPA). A haplotype-based method (sliding window analysis of consecutive SNPs) was used to identify chromosome regions of interest that remained significant at a false discovery rate of 10%. Subsequently, risk estimates were generated for regions with a high level of signal and individual SNPs by unconditional logistic regression adjusting for age, gender and study center. Three regions containing genes associated with renal cancer were identified: caspase 1/5/4/12(CASP 1/5/4/12), epidermal growth factor receptor (EGFR), and insulin-like growth factor binding protein-3 (IGFBP3). We observed that individuals with CASP1/5/4/12 haplotype (spanning area upstream of CASP1 through exon 2 of CASP5) GGGCTCAGT were at higher risk of renal cancer compared to individuals with the most common haplotype (OR:1.40, 95% CI:1.10–1.78, p-value = 0.007). Analysis of EGFR revealed three strong signals within intron 1, particularly a region centered around rs759158 with a global p = 0.006 (GGG: OR:1.26, 95% CI:1.04–1.53 and ATG: OR:1.55, 95% CI:1.14–2.11). A region in IGFBP3 was also associated with increased risk (global p = 0.04). In addition, the number of statistically significant (p-value<0.05) SNP associations observed within these three genes was higher than would be expected by chance on a gene level. To our knowledge, this is the first study to evaluate these genes in relation to renal cancer and there is need to replicate and extend our findings. The specific regions associated with risk may have particular relevance for gene function and/or carcinogenesis. In conclusion, our evaluation has identified common genetic variants in CASP1, CASP5, EGFR, and IGFBP3 that could be associated with renal cancer risk.

Synovium-derived stem cell-based chondrogenesis

Synovium is considered a candidate source of cells for cartilage tissue engineering. Compared with mesenchymal stem cells (MSCs) from other sources, synovium-derived stem cells (SDSCs) have a higher capacity for chondrogenic differentiation. Our objective was to define cocktails of growth factors that support the growth and chondrogenic differentiation of SDSCs in chemically defined medium. We established a fast and highly selective technique of negative isolation of SDSC populations. The individual and combined effects of three growth factors-transforming growth factor-beta1 (TGF-beta1), insulin-like growth factor I (IGF-I), and basic fibroblast growth factor (FGF-2)-were evaluated in serum-free pellet cultures of SDSCs for the chondrogenesis of SDSCs using histology, biochemical analysis, and real-time RT-PCR. In vitro studies identified TGF-beta1 as the key factor for both the growth and chondrogenesis of SDSCs. The highest rates of SDSC growth were observed with the synergistic interaction of all three factors. With respect to chondrogenic differentiation of SDSCs, the interaction of TGF-beta1 and IGF-I applied simultaneously was superior to the sequential application of these two factors or any other combination of growth factors studied. Based on these findings, we propose a two-step protocol for the derivation of chondrogenic SDSCs: a cocktail of TGF-beta1, IGF-I, and FGF-2 is applied first to induce cell growth followed by a cocktail of TGF-beta1 and IGF-I applied to induce chondrogenesis.

Systemic IGF-I administration stimulates the in vivo growth of early, but not advanced, renal cell carcinoma

Insulin-like growth factor I (IGF-I) is a potent mitogen and antiapoptotic factor. Although elevated serum IGF-I levels have been associated with increased cancer risk, it is not yet clear whether IGF-I sensitivity is sustained throughout tumor progression. To evaluate the biological effects of IGF-I during renal cell carcinoma (RCC) establishment and progression, we administered recombinant human IGF-I to severe combined immuno-deficient mice bearing early or more established Caki-2 human RCC tumors. IGF-I significantly enhanced the tumor growth 2.4-fold when administered early after tumor inoculation. This IGF-I-induced growth was accompanied with enhanced tumor cell proliferation, tumor vascularization, as well as increased intratumoral insulin-like growth factor binding protein 3 (IGFBP-3) and pSmad2 levels. In contrast, IGF-I administrated to more established RCC tumors showed no effect on tumor growth, with subsequently much lower Ki-67, IGFBP-3 and pSmad2 levels. Taken together, these data suggest that systemic IGF-I has potent actions during early RCC tumor development with a sustained long-term effect on proliferation and neovascularization although with progression, later tumors appear to become desensitized to systemic IGF-I effects.

Adiposity and age are statistically related to enhanced RASSF1A tumor suppressor gene promoter methylation in normal autopsy kidney tissue

Age, adiposity, and smoking are risk factors for the development of renal cell carcinoma. Hypermethylation of the RAS association domain family 1A gene (RASSF1A) promoter belongs to the most frequently detected epigenetic alterations in human cancers including renal cell carcinoma. RASSF1A is functionally involved in cell cycle control in normal cells and depletion promotes a number of cellular changes increasing the risk for neoplastic growth. We investigated the hypothesis that age, modulated by the factors adiposity and anthracosis as a surrogate for smoking, is a predictor of RASSF1A promoter methylation in normal kidney tissue. Using a cross-sectional study design, we quantitatively analyzed RASSF1A methylation in 78 normal autopsy kidney tissues by quantitative combined bisulfite and restriction analysis and bisulfite sequencing, and statistically evaluated the degree of relative methylation for a relationship with the predictor age and study factors adiposity and state of anthracosis. Statistical analysis showed that age (regression analysis; P < 0.001), adiposity (univariate analysis; P = 0.016), and state of anthracosis (t test; P = 0.005) are each significantly associated with an increase of RASSF1A promoter methylation in normal kidney tissue. However, only age (P = 0.008) and adiposity (P = 0.008) were identified as independent predictors of RASSF1A promoter methylation using covariance analysis. This study provides statistical evidence that the common cancer risk factors age and adiposity enhance RASSF1A promoter methylation in nonmalignant kidney tissue.

IGFBP3 promoter methylation in colorectal cancer: relationship with microsatellite instability, CpG island methylator phenotype, and p53

Insulin-like growth factor binding protein 3 (IGFBP3), which is induced by wild-type p53, regulates IGF and interacts with the TGF-beta pathway. IGFBP3 promoter methylation may occur in colorectal cancer with or without the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and TGFBR2 mutation. We examined the relationship between IGFBP3 methylation, p53 expression, CIMP and MSI in 902 population-based colorectal cancers. Utilizing real-time PCR (MethyLight), we quantified promoter methylation in IGFBP3 and eight other CIMP-high-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1). IGFBP3 methylation was far more frequent in non-MSI-high CIMP-high tumors (85% = 35/41) than in MSI-high CIMP-high (49% = 44/90, P < .0001), MSI-high non-CIMP-high (17% = 6/36, P < .0001), and non-MSI-high non-CIMP-high tumors (22% = 152/680, P < .0001). Among CIMP-high tumors, the inverse relationship between MSI and IGFBP3 methylation persisted in p53-negative tumors (P < .0001), but not in p53-positive tumors. IGFBP3 methylation was associated inversely with TGFBR2 mutation in MSI-high non-CIMP-high tumors (P = .02). In conclusion, IGFBP3 methylation is inversely associated with MSI in CIMP-high colorectal cancers, and this relationship is limited to p53-negative tumors. Our data suggest complex relationship between global genomic/epigenomic phenomena (such as MSI/CIMP), single molecular events (e.g., IGFBP3 methylation, TP53 mutation, and TGFBR2 mutation), and the related pathways.

Predicting outcome to VEGF-targeted therapy in metastatic clear-cell renal cell carcinoma: data from recent studies

Attempts to predict outcome in patients with metastatic clear-cell renal cell carcinoma (RCC) have conventionally been based on pretherapy clinical factors such as performance status, disease-free interval, number of metastatic sites and several laboratory variables. These factors were developed before the era of VEGF-targeted therapy. Recent analysis from trials with anti-VEGF agents indicate that these factors continue to be of major importance in patient prognostication. Additionally, several serum and molecular markers, many of which relate to certain alterations of the von Hippel-Lindau pathway, are currently being investigated. Responses to VEGF-targeted agents appear to be related to a greater modulation of serum VEGF and soluble VEGF receptor levels. The impact of von Hippel-Lindau gene status on response to VEGF-targeted therapy was tested in a large study and was not found to predict a higher response rate to these agents. However, a subset of von Hippel-Lindau mutations that predict a 'loss of function' of the von Hippel-Lindau gene seem to have the best response to these agents. Future prognostic models will incorporate molecular markers with clinical variables to refine prognosis and prediction in metastatic clear-cell RCC patients treated with novel VEGF-targeted agents. These models, if externally and prospectively validated, will culminate in the rational selection of patients for specific VEGF-directed therapeutics.