Gene Summary

Gene:STC1; stanniocalcin 1
Aliases: STC
Summary:This gene encodes a secreted, homodimeric glycoprotein that is expressed in a wide variety of tissues and may have autocrine or paracrine functions. The gene contains a 5' UTR rich in CAG trinucleotide repeats. The encoded protein contains 11 conserved cysteine residues and is phosphorylated by protein kinase C exclusively on its serine residues. The protein may play a role in the regulation of renal and intestinal calcium and phosphate transport, cell metabolism, or cellular calcium/phosphate homeostasis. Overexpression of human stanniocalcin 1 in mice produces high serum phosphate levels, dwarfism, and increased metabolic rate. This gene has altered expression in hepatocellular, ovarian, and breast cancers. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 15 March, 2017


What does this gene/protein do?
Show (16)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Cancer Gene Expression Regulation
  • Paracrine Communication
  • Receptors, Tumor Necrosis Factor
  • eIF-2 Kinase
  • Staging
  • Cell Proliferation
  • p53 Protein
  • Immunohistochemistry
  • Breast Cancer
  • Cell Hypoxia
  • Liver Cancer
  • Neoplasm Invasiveness
  • RT-PCR
  • Intercellular Signaling Peptides and Proteins
  • Oligonucleotide Array Sequence Analysis
  • Apoptosis
  • RNA Interference
  • Tumor Suppressor Proteins
  • Neoplastic Cell Transformation
  • siRNA
  • Up-Regulation
  • HIF1A
  • Tongue Neoplasms
  • Lung Cancer
  • Cell Movement
  • Colorectal Cancer
  • Chromosome 8
  • Survival Rate
  • Lymphatic Metastasis
  • Messenger RNA
  • Neoplasm Metastasis
  • Hydroxamic Acids
  • Biomarkers, Tumor
  • Squamous Cell Carcinoma
  • Gene Expression Profiling
  • Glycoproteins
  • Fibroblasts
  • Western Blotting
  • Gene Expression
Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: STC1 (cancer-related)

Park WY, Hong BJ, Lee J, et al.
H3K27 Demethylase JMJD3 Employs the NF-κB and BMP Signaling Pathways to Modulate the Tumor Microenvironment and Promote Melanoma Progression and Metastasis.
Cancer Res. 2016; 76(1):161-70 [PubMed] Related Publications
Histone methylation is a key epigenetic mark that regulates gene expression. Recently, aberrant histone methylation patterns caused by deregulated histone demethylases have been associated with carcinogenesis. However, the role of histone demethylases, particularly the histone H3 lysine 27 (H3K27) demethylase JMJD3, remains largely uncharacterized in melanoma. Here, we used human melanoma cell lines and a mouse xenograft model to demonstrate a requirement for JMJD3 in melanoma growth and metastasis. Notably, in contrast with previous reports examining T-cell acute lymphoblastic leukemia and hepatoma cells, JMJD3 did not alter the general proliferation rate of melanoma cells in vitro. However, JMJD3 conferred melanoma cells with several malignant features such as enhanced clonogenicity, self-renewal, and transendothelial migration. In addition, JMJD3 enabled melanoma cells not only to create a favorable tumor microenvironment by promoting angiogenesis and macrophage recruitment, but also to activate protumorigenic PI3K signaling upon interaction with stromal components. Mechanistic investigations demonstrated that JMJD3 transcriptionally upregulated several targets of NF-κB and BMP signaling, including stanniocalcin 1 (STC1) and chemokine (C-C motif) ligand 2 (CCL2), which functioned as downstream effectors of JMJD3 in self-renewal and macrophage recruitment, respectively. Furthermore, JMJD3 expression was elevated and positively correlated with that of STC1 and CCL2 in human malignant melanoma. Moreover, we found that BMP4, another JMJD3 target gene, regulated JMJD3 expression via a positive feedback mechanism. Our findings reveal a novel epigenetic mechanism by which JMJD3 promotes melanoma progression and metastasis, and suggest JMJD3 as a potential target for melanoma treatment.

Abaza HM, Elmougy MI, El Maraghy HM, Mahmoud HM
Stanniocalcin1 gene expression in patients with acute leukemia: impact on response to therapy and disease outcome.
Int J Lab Hematol. 2016; 38(1):81-9 [PubMed] Related Publications
INTRODUCTION: Stanniocalcin1 (STC1) is a hormone that regulates cell growth and survival; this study aimed to evaluate the STC1 gene expression in patients with acute leukemia and assess its prognostic significance.
METHODS: Seventy-six patients with acute leukemia were enrolled for determination of mRNA STC1 by real-time quantitative polymerase chain reaction at diagnosis and at day 28.
RESULTS: Median STC1 gene expression was 16.2 and 4.43 in patients with acute myeloid leukemia and 9.67 and 2.37 in patients with acute lymphoblastic leukemia on days 0 and 28, respectively. A cutoff level for STC1 gene expression was established subdividing patients into high- and low-STC1 gene expression groups. Median STC1 gene expression at days 0 and 28 was significantly higher among patients who were nonresponders to therapy than among those who were therapy responders in both groups. Patients achieving complete remission had significantly lower baseline STC1 gene expression than those in relapse. High STC1 gene expression was associated with shorter overall and disease-free survival times.
CONCLUSION: STC1 gene expression at diagnosis might be a useful prognostic marker for clinical outcome and monitoring therapeutic response in patients with acute leukemia.

Dai D, Wang Q, Li X, et al.
Klotho inhibits human follicular thyroid cancer cell growth and promotes apoptosis through regulation of the expression of stanniocalcin-1.
Oncol Rep. 2016; 35(1):552-8 [PubMed] Related Publications
The new anti-aging gene Klotho has been identified as a multi-functional humoral factor which influences multiple biological processes, including tumor progression. Although ample evidence indicates that Klotho plays important roles in cervical, lung and breast cancer, the role and mechanism of Klotho in thyroid cancer are still unclear. The present study aimed to investigate the effects and mechanisms of Klotho in human thyroid cancer cell lines FTC133 and FTC238. Klotho overexpression markedly reduced thyroid cancer FTC133 and FTC238 cell proliferation and enhanced apoptosis, whereas, Klotho silencing in the FTC133 and FTC238 cells increased cell growth. Moreover, soluble human KL1 (sKL) and Klotho overexpression had a similar effect on FTC133 and FTC238 cell growth. A high level of Klotho was also found to be associated with a low level of stanniocalcin 1 (STC1) in both the FTC133 and FTC238 cell lines. STC1 silencing significantly inhibited thyroid cancer cell proliferation, whereas recombinant human STC1 (hSTC1) markedly enhanced cell proliferation. In addition, our study demonstrated that hSTC1 treatment attenuated Klotho-induced inhibition of cell proliferation and promotion of apoptosis. Our data revealed the existence of a moderating effect between Klotho and STC1, where Klotho may inhibit thyroid tumor progression by inhibiting the tumor marker level of STC1.

Yeung BH, Shek FH, Lee NP, Wong CK
Stanniocalcin-1 Reduces Tumor Size in Human Hepatocellular Carcinoma.
PLoS One. 2015; 10(10):e0139977 [PubMed] Free Access to Full Article Related Publications
Growing evidence has revealed high expression levels of stanniocalcin-1 (STC1) in different types of human cancers. Numerous experimental studies using cancer cell lines demonstrated the involvement of STC1 in inflammatory and apoptotic processes; however the role of STC1 in carcinogenesis remains elusive. Hepatocellular carcinoma (HCC) an exemplified model of inflammation-related cancer, represents a paradigm of studying the association between STC1 and tumor development. Therefore, we conducted a statistical analysis on the expression levels of STC1 using clinicopathological data from 216 HCC patients. We found that STC1 was upregulated in the tumor tissues and its expression levels was positively correlated with the levels of interleukin (IL)-6 and IL-8. Intriguingly tumors with greater expression levels of STC1 (tumor/normal ≥ 2) were significantly smaller than the lower level (tumor/normal<2) samples (p = 0.008). A pharmacological approach was implemented to reveal the functional correlation between STC1 and the ILs in the HCC cell-lines. IL-6 and IL-8 treatment of Hep3B cells induced STC1 expression. Lentiviral-based STC1 overexpression in Hep3B and MHCC-97L cells however showed inhibitory action on the pro-migratory effects of IL-6 and IL-8 and reduced size of tumor spheroids. The inhibitory effect of STC1 on tumor growth was confirmed in vivo using the stable STC1-overexpressing 97L cells on a mouse xenograft model. Genetic analysis of the xenografts derived from the STC1-overexpressing 97L cells, showed upregulation of the pro-apoptotic genes interleukin-12 and NOD-like receptor family, pyrin domain-containing 3. Collectively, the anti-inflammatory and pro-apoptotic functions of STC1 were suggested to relate its inhibitory effect on the growth of HCC cells. This study supports the notion that STC1 may be a potential therapeutic target for inflammatory tumors in HCC patients.

Bollard J, Massoma P, Vercherat C, et al.
The axon guidance molecule semaphorin 3F is a negative regulator of tumor progression and proliferation in ileal neuroendocrine tumors.
Oncotarget. 2015; 6(34):36731-45 [PubMed] Free Access to Full Article Related Publications
Gastro-intestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, frequently metastatic, raising difficult clinical and therapeutic challenges due to a poor knowledge of their biology. As neuroendocrine cells express both epithelial and neural cell markers, we studied the possible involvement in GI-NETs of axon guidance molecules, which have been shown to decrease tumor cell proliferation and metastatic dissemination in several tumor types. We focused on the role of Semaphorin 3F (SEMA3F) in ileal NETs, one of the most frequent subtypes of GI-NETs.SEMA3F expression was detected in normal neuroendocrine cells but was lost in most of human primary tumors and all their metastases. SEMA3F loss of expression was associated with promoter gene methylation. After increasing endogenous SEMA3F levels through stable transfection, enteroendocrine cell lines STC-1 and GluTag showed a reduced proliferation rate in vitro. In two different xenograft mouse models, SEMA3F-overexpressing cells exhibited a reduced ability to form tumors and a hampered liver dissemination potential in vivo. This resulted, at least in part, from the inhibition of mTOR and MAPK signaling pathways.This study demonstrates an anti-tumoral role of SEMA3F in ileal NETs. We thus suggest that SEMA3F and/or its cellular signaling pathway could represent a target for ileal NET therapy.

Ma X, Gu L, Li H, et al.
Hypoxia-induced overexpression of stanniocalcin-1 is associated with the metastasis of early stage clear cell renal cell carcinoma.
J Transl Med. 2015; 13:56 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Although metastasis of clear cell renal cell carcinoma (ccRCC) is predominantly observed in late stage tumors, early stage metastasis of ccRCC can also be found with indefinite molecular mechanism, leading to inappropriate clinical decisions and poor prognosis. Stanniocalcin-1 (STC1) is a glycoprotein hormone involved in calcium/phosphate homeostasis, which regulates various cellular processes in normal development and tumorigenesis. This study aimed to investigate the role and mechanism of regulation of STC1 in the metastasis of early stage ccRCC.
METHODS: STC1 mRNA and protein expression was determined in ccRCC surgical specimens, RCC cell lines, and human kidney tubule epithelial cell line HKC by real-time polymerase chain reaction (RT-PCR) and western blotting. Immunohistochemistry staining (IHC) and immunofluorescence were also used to examine the expression and localization of STC1 in ccRCC tissues and cancer cells. Knockdown and overexpression studies were conducted in vitro in RCC cell lines using small interfering RNAs (siRNA) and lentiviral-mediated gene delivery to evaluate the role of STC1 in cell proliferation, anchorage-dependent and independent growth, cell cycle control, and migration and invasion.
RESULTS: STC1 mRNA and protein expression were significantly up-regulated in tumors when compared with non-tumor tissues, with the greatest increase in expression observed in metastatic tissues. Clinicopathological analysis revealed that STC1 mRNA expression was associated with Fuhrman tumor grade (P = 0.008) and overall Tumor Node Metastasis (TNM) staging (P = 0.018). STC1 expression was elevated in T1 stage metastatic tumors when compared with localized tumors, and was positively correlated with average tumor diameter. Silencing of STC1 expression by Caki-1 and A498 resulted in the inhibition of cell proliferation, migration, and invasion, meanwhile down-regulation of STC1 impaired epithelial-mesenchymal transition (EMT) of ccRCC cell lines. Overexpression of STC1 in Caki-2 enhanced cell growth and proliferation but not migration and invasion. Further investigation identified hypoxia and HIF-1α as candidate regulators of STC1 expression.
CONCLUSIONS: Our findings demonstrate a role for STC1 in metastasis of early stage ccRCC and suggest that STC1 may be a biomarker of potential value both for the prognosis of this disease and for guiding clinical decisions regarding surgical strategies and adjuvant treatment.

Hayase S, Sasaki Y, Matsubara T, et al.
Expression of stanniocalcin 1 in thyroid side population cells and thyroid cancer cells.
Thyroid. 2015; 25(4):425-36 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Mouse thyroid side population (SP) cells consist of a minor population of mouse thyroid cells that may have multipotent thyroid stem cell characteristics. However the nature of thyroid SP cells remains elusive, particularly in relation to thyroid cancer. Stanniocalcin (STC) 1 and 2 are secreted glycoproteins known to regulate serum calcium and phosphate homeostasis. In recent years, the relationship of STC1/2 expression to cancer has been described in various tissues.
METHOD: Microarray analysis was carried out to determine genes up- and down-regulated in thyroid SP cells as compared with non-SP cells. Among genes up-regulated, stanniocalcin 1 (STC1) was chosen for study because of its expression in various thyroid cells by Western blotting and immunohistochemistry.
RESULTS: Gene expression analysis revealed that genes known to be highly expressed in cancer cells and/or involved in cancer invasion/metastasis were markedly up-regulated in SP cells from both intact as well as partial thyroidectomized thyroids. Among these genes, expression of STC1 was found in five human thyroid carcinoma-derived cell lines as revealed by analysis of mRNA and protein, and its expression was inversely correlated with the differentiation status of the cells. Immunohistochemical analysis demonstrated higher expression of STC1 in the thyroid tumor cell line and thyroid tumor tissues from humans and mice.
CONCLUSION: These results suggest that SP cells contain a population of cells that express genes also highly expressed in cancer cells including Stc1, which warrants further study on the role of SP cells and/or STC1 expression in thyroid cancer.

Chang AC, Doherty J, Huschtscha LI, et al.
STC1 expression is associated with tumor growth and metastasis in breast cancer.
Clin Exp Metastasis. 2015; 32(1):15-27 [PubMed] Related Publications
Stanniocalcin-1 (STC1) is a secreted glycoprotein implicated in several pathologies including retinal degeneration, cerebral ischemia, angiogenesis and inflammation. Aberrant STC1 expression has been reported in breast cancer but the significance of this is not clear. High levels of STC1 expression were found in the aggressive 4T1 murine mammary tumor cells and in the MDA-MB-231 human breast cancer line. To investigate its significance, stable clones with STC1 down-regulation using shRNA were generated in both tumor models. The consequences of STC1 down-regulation on cell proliferation, chemotactic invasion, tumor growth and metastasis were assessed. Down-regulation of STC1 in the 4T1 murine mammary tumor cells had a major impact on mammary tumor growth. This observation was replicated in a second tumor model with the MDA-MB-231 human breast cancer line, with a significant reduction in primary tumor formation and a major inhibition of metastasis as well. Interestingly, in both models, proliferation in vitro was not affected. Subsequent microarray gene expression profiling identified 30 genes to be significantly altered by STC1 down-regulation, the majority of which are associated with known hallmarks of carcinogenesis. Furthermore, bioinformatic analysis of breast cancer datasets revealed that high expression of STC1 is associated with poor survival. This is the first study to show definitively that STC1 plays an oncogenic role in breast cancer, and indicates that STC1 could be a potential therapeutic target for treatment of breast cancer patients.

Couderc C, Bollard J, Couté Y, et al.
Mechanisms of local invasion in enteroendocrine tumors: identification of novel candidate cytoskeleton-associated proteins in an experimental mouse model by a proteomic approach and validation in human tumors.
Mol Cell Endocrinol. 2015; 399:154-63 [PubMed] Related Publications
Small-intestinal neuroendocrine tumors (SI-NETs) are defined as locally invasive only after extension to the muscularis propria. To gain further insight into the molecular mechanisms, we applied a proteomic approach to an orthotopic xenograft model to identify candidate proteins evaluable in human SI-NETs. After grafting STC-1 neuroendocrine tumor cells on the caecum of nude mice, comparative proteomic studies were performed between the pre-invasive and the invasive stages, respectively 2 and 8 weeks after grafting. We identified 24 proteins displaying at least a 1.5-fold differential expression between 2 and 8 week-stages. Most were cytoskeleton-associated proteins, among which five showed decreasing expression levels (CRMP2, TCP1ε, TPM2, vimentin, desmin) and two increasing expression levels (14-3-3γ, CK8). Changes for CRMP2, TCP1ε, TPM2 and 14-3-3γ were confirmed in experimental tumors and in a series of 28 human SI-NETs. In conclusion, our results underline the relevance of proteomics to identify novel biomarkers of tissue invasion.

Sun Y, Shen S, Tang H, et al.
miR-429 identified by dynamic transcriptome analysis is a new candidate biomarker for colorectal cancer prognosis.
OMICS. 2014; 18(1):54-64 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer (CRC) is a common malignant gastrointestinal cancer. Efforts for preventive and personalized medicine have intensified in the last decade with attention to novel forms of biomarkers. In the present study, microRNA and genetic analyses were performed in tandem for differential transcriptome profiling between primary tumors with or without nodes or distant metastases. Serial Test Cluster (STC) analysis demonstrated that 20 genes and two microRNAs showed distinctive expression patterns associated with the tumor, node, and metastasis (TNM) stage. The selected target genes were characterized by GO and Pathway analysis. A microRNA-target gene network analysis showed that miR-429 resided in the center of the network, indicating that miR-429 might serve important roles in the development of CRC. Real-time PCR and tissue microarrays showed that miR-429 had a dynamic expression pattern during the CRC progression stage, and was significantly downregulated in stage II and stage III clinical progression. The low expression of miR-429 was correlated with poor prognosis for CRC. Taken together, miR-429 warrant further clinical translation research as a candidate biomarker for CRC prognosis. Additional downstream targets and attendant gene function also need to be discerned to design a sound critical path to personalized medicine for persons susceptible to, or diagnosed with CRC.

Rajaram M, Li J, Egeblad M, Powers RS
System-wide analysis reveals a complex network of tumor-fibroblast interactions involved in tumorigenicity.
PLoS Genet. 2013; 9(9):e1003789 [PubMed] Free Access to Full Article Related Publications
Many fibroblast-secreted proteins promote tumorigenicity, and several factors secreted by cancer cells have in turn been proposed to induce these proteins. It is not clear whether there are single dominant pathways underlying these interactions or whether they involve multiple pathways acting in parallel. Here, we identified 42 fibroblast-secreted factors induced by breast cancer cells using comparative genomic analysis. To determine what fraction was active in promoting tumorigenicity, we chose five representative fibroblast-secreted factors for in vivo analysis. We found that the majority (three out of five) played equally major roles in promoting tumorigenicity, and intriguingly, each one had distinct effects on the tumor microenvironment. Specifically, fibroblast-secreted amphiregulin promoted breast cancer cell survival, whereas the chemokine CCL7 stimulated tumor cell proliferation while CCL2 promoted innate immune cell infiltration and angiogenesis. The other two factors tested had minor (CCL8) or minimally (STC1) significant effects on the ability of fibroblasts to promote tumor growth. The importance of parallel interactions between fibroblasts and cancer cells was tested by simultaneously targeting fibroblast-secreted amphiregulin and the CCL7 receptor on cancer cells, and this was significantly more efficacious than blocking either pathway alone. We further explored the concept of parallel interactions by testing the extent to which induction of critical fibroblast-secreted proteins could be achieved by single, previously identified, factors produced by breast cancer cells. We found that although single factors could induce a subset of genes, even combinations of factors failed to induce the full repertoire of functionally important fibroblast-secreted proteins. Together, these results delineate a complex network of tumor-fibroblast interactions that act in parallel to promote tumorigenicity and suggest that effective anti-stromal therapeutic strategies will need to be multi-targeted.

Gañán-Gómez I, Wei Y, Yang H, et al.
Oncogenic functions of the transcription factor Nrf2.
Free Radic Biol Med. 2013; 65:750-64 [PubMed] Related Publications
Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that controls the expression of a large pool of antioxidant and cytoprotective genes regulating the cellular response to oxidative and electrophilic stress. Nrf2 is negatively regulated by Kelch-like ECH-associated protein 1 (Keap1) and, upon stimulation by an oxidative or electrophilic insult, is rapidly activated by protein stabilization. Owing to its cytoprotective functions, Nrf2 has been traditionally studied in the field of chemoprevention; however, there is accumulated evidence that Keap1/Nrf2 mutations or unbalanced regulation that leads to overexpression or hyperactivation of Nrf2 may participate in tumorigenesis and be involved in chemoresistance of a wide number of solid cancers and leukemias. In addition to protecting cells from reactive oxygen species, Nrf2 seems to play a direct role in cell growth control and is related to apoptosis-regulating pathways. Moreover, Nrf2 activity is connected with oncogenic kinase pathways, structural proteins, hormonal regulation, other transcription factors, and epigenetic enzymes involved in the pathogenesis of various types of tumors. The aim of this review is to compile and summarize existing knowledge of the oncogenic functions of Nrf2 to provide a solid basis for its potential use as a molecular marker and pharmacological target in cancer.

Guo F, Li Y, Wang J, et al.
Stanniocalcin1 (STC1) Inhibits Cell Proliferation and Invasion of Cervical Cancer Cells.
PLoS One. 2013; 8(1):e53989 [PubMed] Free Access to Full Article Related Publications
STC1 is a glycoprotein hormone involved in calcium/phosphate (Pi) homeostasis. There is mounting evidence that STC1 is tightly associated with the development of cancer. But the function of STC1 in cancer is not fully understood. Here, we found that STC1 is down-regulated in Clinical tissues of cervical cancer compared to the adjacent normal cervical tissues (15 cases). Subsequently, the expression of STC1 was knocked down by RNA interference in cervical cancer CaSki cells and the low expression promoted cell growth, migration and invasion. We also found that STC1 overexpression inhibited cell proliferation and invasion of cervical cancer cells. Moreover, STC1 overexpression sensitized CaSki cells to drugs. Further, we showed that NF-κB p65 protein directly bound to STC1 promoter and activated the expression of STC1 in cervical cancer cells. Thus, these results provided evidence that STC1 inhibited cell proliferation and invasion through NF-κB p65 activation in cervical cancer.

Peña C, Céspedes MV, Lindh MB, et al.
STC1 expression by cancer-associated fibroblasts drives metastasis of colorectal cancer.
Cancer Res. 2013; 73(4):1287-97 [PubMed] Related Publications
Platelet-derived growth factor (PDGF) receptor signaling is a major functional determinant of cancer-associated fibroblasts (CAF). Elevated expression of PDGF receptors on stromal CAFs is associated with metastasis and poor prognosis, but mechanism(s) that underlie these connections are not understood. Here, we report the identification of the secreted glycoprotein stanniocalcin-1 (STC1) as a mediator of metastasis by PDGF receptor function in the setting of colorectal cancer. PDGF-stimulated fibroblasts increased migration and invasion of cocultured colorectal cancer cells in an STC1-dependent manner. Analyses of human colorectal cancers revealed significant associations between stromal PDGF receptor and STC1 expression. In an orthotopic mouse model of colorectal cancer, tumors formed in the presence of STC1-deficient fibroblasts displayed reduced intravasation of tumor cells along with fewer and smaller distant metastases formed. Our results reveal a mechanistic basis for understanding the contribution of PDGF-activated CAFs to cancer metastasis.

Yun SH, Park ES, Shin SW, et al.
Stichoposide C induces apoptosis through the generation of ceramide in leukemia and colorectal cancer cells and shows in vivo antitumor activity.
Clin Cancer Res. 2012; 18(21):5934-48 [PubMed] Related Publications
PURPOSE: Marine triterpene glycosides that are physiologically active natural compounds isolated from sea cucumbers (holothurians) and sponges have antifungal, cytotoxic, and antitumor activities, whose specific molecular mechanisms remain to be elucidated. In this study, we examined if and through which mechanisms stichoposide C (STC) from Thelenota anax (family Stichopodidae) induces apoptosis in leukemia and colorectal cancer cells.
EXPERIMENTAL DESIGN: We examined STC-induced apoptosis in human leukemia and colorectal cancer cells in the context of mitochondrial injury and signaling pathway disturbances, and investigated the antitumor effect of STC in mouse CT-26 subcutaneous tumor and HL-60 leukemia xenograft models.
RESULTS: We found that STC induces apoptosis in these cells in a dose-dependent manner and leads to the activation of Fas and caspase-8, cleavage of Bid, mitochondrial damage, and activation of caspase-3. STC activates acid sphingomyelinase (SMase) and neutral SMase, which resulted in the generation of ceramide. Specific inhibition of acid SMase or neutral SMase and siRNA knockdown experiments partially blocked STC-induced apoptosis. Moreover, STC markedly reduced tumor growth of HL-60 xenograft and CT-26 subcutaneous tumors and increased ceramide generation in vivo.
CONCLUSIONS: Ceramide generation by STC, through activation of acid and neutral SMase, may in part contribute to STC-induced apoptosis and antitumor activity. Thus, STC may have therapeutic relevance for human leukemia and colorectal cancer.

Ching LY, Yeung BH, Wong CK
Synergistic effect of p53 on TSA-induced stanniocalcin 1 expression in human nasopharyngeal carcinoma cells, CNE2.
J Mol Endocrinol. 2012; 48(3):241-50 [PubMed] Related Publications
Human stanniocalcin 1 (STC1) has recently been identified as a putative protein factor involved in cellular apoptosis. The use of histone deacetylase inhibitor (i.e. trichostatin A (TSA)) and doxorubicin (Dox) is one of the common treatment methods to induce apoptosis in human cancer cells. A study on TSA and Dox-mediated apoptosis may shed light on the regulation and function of STC1 in cancer treatment. In this study, TSA and Dox cotreatment in human nasopharyngeal carcinoma cells (CNE2) elicited synergistic effects on STC1 gene expression and cellular apoptosis. An activation of p53 (TP53) transcriptional activity in Dox- or Dox+TSA-treated cells was revealed by the increased expression levels of p53 mRNA/protein as well as p53-driven luciferase activities. To elucidate the possible involvement of p53 in STC1 gene transcription, a vector expressing wild-type or dominant negative (DN) p53 was transiently transfected into the cells. Both STC1 promoter luciferase constructs and chromatin immunoprecipitation assays did not support the direct role of p53 in STC1 gene transactivation. However, the synergistic effects of p53 on the induction of NF-κB phosphorylation and the recruitment of acetylated histone H3 in STC1 promoter were observed in TSA-cotreated cells. The overexpression of exogenous STC1 sensitized apoptosis in Dox-treated cells. Taken together, this study provides data to show the cross talk of NF-κB, p53, and histone protein in the regulation of STC1 expression and function.

Yeung BH, Law AY, Wong CK
Evolution and roles of stanniocalcin.
Mol Cell Endocrinol. 2012; 349(2):272-80 [PubMed] Related Publications
In fish, stanniocalcin-1 (STC1) is a key endocrine factor that acts on gill, intestine and kidney to regulate serum calcium and phosphate homeostasis. The recent identification and study of mammalian STCs (STC1 and STC2) revealed that the hormones are made in virtually all tissues and they act primarily as paracrine/autocrine factors to regulate various biological functions. Based on their ubiquitous expression patterns and generally undetectable levels in blood serum, it is unlikely that the mammalian STCs play important roles in serum Ca(2+)/P(i) homeostasis. However current evidences still support the local action of STCs in Ca(2+) and P(i) transport, probably via their action on Ca(2+)-channels and Na(+)/P(i) co-transporter. At present, information about the sequence, expression and distribution of the STC receptor(s) is lacking. However, recent emerging evidence hints the involvement of STC1 and STC2 in the sub-cellular functions of mitochondria and endoplasmic reticulum respectively, particularly responding to oxidative stress and unfolded protein response. With increasing evidence that demonstrates the local actions of STCs, the focus of the research has been moved to cellular inflammation and carcinogenesis. This review integrates the information available on STCs in fish and mammals, focusing mainly on their embryonic origin, tissue distribution, their potential regulatory mechanisms and the modes of action, and their physiological and pathophysiological functions, particularly in cancer biology.

Gloesenkamp CR, Nitzsche B, Ocker M, et al.
AKT inhibition by triciribine alone or as combination therapy for growth control of gastroenteropancreatic neuroendocrine tumors.
Int J Oncol. 2012; 40(3):876-88 [PubMed] Related Publications
Up-regulation of phosphatidylinositol-3-kinase (PI3K)-AKT signaling facilitates tumor cell growth and inhibits cell demise. The AKT-pathway also plays an important role in cytostatic therapy resistance and response to hypoxia and angiogenesis. Using real-time cell proliferation assay we examined the potency of triciribine in three distinct neuroendocrine gastrointestinal tumor cell lines. Also we investigated triciribine's induction of apoptosis and effects on a broad range of cancer-associated gene products. Furthermore, we characterized the role of PTEN as a possible predictor of sensitivity to triciribine in GEP-NETs. We also looked for additive anti-neoplastic effects of triciribine when combined with conventional cytostatic drugs or other targeted drugs, affecting different molecules of the PI3K-AKT-pathway and we assessed the potency of triciribine to inhibit tumor growth in vivo, by using the chick chorioallantoic membrane assay. Treatment of insulinoma (CM) or gut neuroendocrine tumor cells (STC-1) with triciribine significantly reduced tumor cell growth by 59% and 65%, respectively. By contrast, the highly expressing PTEN carcinoid cell line BON did not respond, even at higher doses. Combinations of triciribine with classic cytostatic drugs as well as drugs targeting other molecules of the PI3K-AKT-pathway led to synergistic anti-proliferative effects. Additional in vivo-evaluations confirmed the anti-neoplastic potency of triciribine. Thus, our data show that inhibition the AKT-pathway potently reduces the growth of GEP-NET cells alone or in combination therapies. AKT inhibition may provide a rationale for future evaluations.

Orr B, Riddick AC, Stewart GD, et al.
Identification of stromally expressed molecules in the prostate by tag-profiling of cancer-associated fibroblasts, normal fibroblasts and fetal prostate.
Oncogene. 2012; 31(9):1130-42 [PubMed] Free Access to Full Article Related Publications
The stromal microenvironment has key roles in prostate development and cancer, and cancer-associated fibroblasts (CAFs) stimulate tumourigenesis via several mechanisms including the expression of pro-tumourigenic factors. Mesenchyme (embryonic stroma) controls prostate organogenesis, and in some circumstances can re-differentiate prostate tumours. We have applied next-generation Tag profiling to fetal human prostate, normal human prostate fibroblasts (NPFs) and CAFs to identify molecules expressed in prostatic stroma. Comparison of gene expression profiles of a patient-matched pair of NPFs vs CAFs identified 671 transcripts that were enriched in CAFs and 356 transcripts whose levels were decreased, relative to NPFs. Gene ontology analysis revealed that CAF-enriched transcripts were associated with prostate morphogenesis and CAF-depleted transcripts were associated with cell cycle. We selected mRNAs to follow-up by comparison of our data sets with published prostate cancer fibroblast microarray profiles as well as by focusing on transcripts encoding secreted and peripheral membrane proteins, as well as mesenchymal transcripts identified in a previous study from our group. We confirmed differential transcript expression between CAFs and NPFs using QrtPCR, and defined protein localization using immunohistochemistry in fetal prostate, adult prostate and prostate cancer. We demonstrated that ASPN, CAV1, CFH, CTSK, DCN, FBLN1, FHL1, FN, NKTR, OGN, PARVA, S100A6, SPARC, STC1 and ZEB1 proteins showed specific and varied expression patterns in fetal human prostate and in prostate cancer. Colocalization studies suggested that some stromally expressed molecules were also expressed in subsets of tumour epithelia, indicating that they may be novel markers of EMT. Additionally, two molecules (ASPN and STC1) marked overlapping and distinct subregions of stroma associated with tumour epithelia and may represent new CAF markers.

Cornmark L, Lønne GK, Jögi A, Larsson C
Protein kinase Cα suppresses the expression of STC1 in MDA-MB-231 breast cancer cells.
Tumour Biol. 2011; 32(5):1023-30 [PubMed] Related Publications
Several protein kinase C (PKC) isoforms have been shown to influence different cellular processes that may contribute to the malignancy of breast cancer cells. To obtain insight into mechanisms mediating the PKC effects, global gene expression was analyzed in MDA-MB-231 breast cancer cells in which PKCα, PKCδ or PKCε had been down-regulated with siRNA. Gene set enrichment analyses revealed that hypoxia-induced genes were enriched among genes that increased in PKCα-down-regulated cells. The STC1 mRNA, encoding stanniocalcin 1, was particularly up-regulated following depletion of PKCα and was also induced by hypoxia. Both hypoxia and PKCα down-regulation also led to increased STC1 protein levels. The results demonstrate that PKCα suppresses the expression of STC1 in breast cancer cells.

Law AY, Yeung BH, Ching LY, Wong CK
Sp1 is a transcription repressor to stanniocalcin-1 expression in TSA-treated human colon cancer cells, HT29.
J Cell Biochem. 2011; 112(8):2089-96 [PubMed] Related Publications
Our previous study demonstrated that, stanniocalcin-1 (STC1) was a target of histone deacetylase (HDAC) inhibitors and was involved in trichostatin A (TSA) induced apoptosis in the human colon cancer cells, HT29. In this study, we reported that the transcriptional factor, specificity protein 1 (Sp1) in association with retinoblastoma (Rb) repressed STC1 gene transcription in TSA-treated HT29 cells. Our data demonstrated that, a co-treatment of the cells with TSA and Sp1 inhibitor, mithramycin A (MTM) led to a marked synergistic induction of STC1 transcript levels, STC1 promoter (1 kb)-driven luciferase activity and an increase of apoptotic cell population. The knockdown of Sp1 gene expression in TSA treated cells, revealed the repressor role of Sp1 in STC1 transcription. Using a protein phosphatase inhibitor okadaic acid (OKA), an increase of Sp1 hyperphosphorylation and so a reduction of its transcriptional activity, led to a significant induction of STC1 gene expression. Chromatin immunoprecipitation (ChIP) assay revealed that Sp1 binding on STC1 proximal promoter in TSA treated cells. The binding of Sp1 to STC1 promoter was abolished by the co-treatment of MTM or OKA in TSA-treated cells. Re-ChIP assay illustrated that Sp1-mediated inhibition of STC1 transcription was associated with the recruitment of another repressor molecule, Rb. Collectively our findings identify STC1 is a downstream target of Sp1.

Tamura S, Oshima T, Yoshihara K, et al.
Clinical significance of STC1 gene expression in patients with colorectal cancer.
Anticancer Res. 2011; 31(1):325-9 [PubMed] Related Publications
BACKGROUND: Recent studies suggest that altered patterns of stanniocalcin 1 (STC1) gene expression have a role in human carcinogenesis. This study examined the relationship between the relative expression of the STC1 gene and clinicopathological factors in patients with colorectal cancer.
PATIENTS AND METHODS: Surgical specimens of cancer tissue and adjacent normal mucosa were obtained from 202 patients with colorectal carcinomas. The relative expression levels of STC1 mRNA in the cancer and the normal adjacent mucosa were measured by quantitative real-time, reverse-transcriptase polymerase chain reaction.
RESULTS: The relative expression levels of the STC1 gene were higher in the cancer tissue than in the normal adjacent mucosa and high expression of STC1 correlated with poor postoperative survival.
CONCLUSION: High expression of the STC1 gene might be a useful predictor of poor postoperative outcome in patients with colorectal cancer.

Liu G, Yang G, Chang B, et al.
Stanniocalcin 1 and ovarian tumorigenesis.
J Natl Cancer Inst. 2010; 102(11):812-27 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Stanniocalcin 1 (STC1) is a secreted glycoprotein hormone. High expression of STC1 has been associated with several cancers including ovarian cancer, but its role in the development of ovarian cancer is not clear.
METHODS: We used five human ovarian epithelial cancer cell lines (OVCA420, OVCA432, OVCA433, SKOV3, and HEY), immortalized human ovarian surface epithelial cells (T29 and T80), ovarian cancer tissues from 342 patients, serum from 73 ovarian cancer patients and from58 control subjects, and 116 mice, with six or eight per group. Protein expression was assessed. Cells overexpressing STC1 protein were generated by ectopic expression of human STC1 cDNA. STC1 expression was silenced by using small interfering RNA against STC1. Cell proliferation, migration, colony formation, and apoptosis were assessed. Xenograft tumor growth in mice was studied. Neutralizing anti-STC1 antibody was used to inhibit STC1 function. All statistical tests were two-sided.
RESULTS: STC1 protein expression was higher in all human ovarian cancer cell lines examined than in immortalized human ovarian epithelial cell lines, higher in ovarian cancer tissue than in normal ovarian tissue (P < .001), and higher in serum from ovarian cancer patients than from control subjects (P = .021). Ovarian cancer cells with STC1 overexpression, compared with corresponding control cells, had increased cell proliferation, migration, and colony formation in cell culture and increased growth of xenograft tumors in mice. These activities in normal or malignant ovarian cells with STC1 overexpression, compared with control cells, were also accompanied by increased expression of cell cycle regulatory proteins and antiapoptotic proteins but decreased cleavage of several caspases. Within 24 hours of treatment, apoptosis in cultures of HEY ovarian cancer cells treated with neutralizing anti-STC1 monoclonal antibody was higher (17.3% apoptotic cells) than that in cultures treated with mouse IgG control cells (4.4%) (12.9% difference, 95% confidence interval = 11.6% to 14.2%).
CONCLUSIONS: STC1 protein may be involved in ovarian tumorigenesis.

Law AY, Wong CK
Stanniocalcin-2 is a HIF-1 target gene that promotes cell proliferation in hypoxia.
Exp Cell Res. 2010; 316(3):466-76 [PubMed] Related Publications
Stanniocalcin-2 (STC2), the paralog of STC1, has been suggested as a novel target of oxidative stress response to protect cells from apoptosis. The expression of STC2 has been reported to be highly correlated with human cancer development. In this study, we reported that STC2 is a HIF-1 target gene and is involved in the regulation of cell proliferation. STC2 was shown to be up-regulated in different breast and ovarian cancer cells, following exposure to hypoxia. Using ovarian cancer cells (SKOV3), the underlying mechanism of HIF-1 mediated STC2 gene transactivation was characterized. Hypoxia-induced STC2 expression was found to be HIF-1alpha dependent and required the recruitment of p300 and HDAC7. Using STC2 promoter deletion constructs and site-directed mutagenesis, two authentic consensus HIF-1 binding sites were identified. Under hypoxic condition, the silencing of STC2 reduced while the overexpression of STC2 increased the levels of phosphorylated retinoblastoma and cyclin D in both SKOV3 and MCF7 cells. The change in cell cycle proteins correlated with the data of the serial cell counts. The results indicated that cell proliferation was reduced in STC2-silenced cells but was increased in STC2-overexpressing hypoxic cells. Solid tumor progression is usually associated with hypoxia. The identification and functional analysis of STC2 up-regulation by hypoxia, a feature of the tumor microenvironment, sheds light on a possible role for STC2 in tumors.

Daniel AR, Lange CA
Protein kinases mediate ligand-independent derepression of sumoylated progesterone receptors in breast cancer cells.
Proc Natl Acad Sci U S A. 2009; 106(34):14287-92 [PubMed] Free Access to Full Article Related Publications
In advanced breast tumors, protein kinases are upregulated and steroid hormone receptors often function independently of ligand. Herein, we explored mechanisms of ligand-independent progesterone receptor (PR) activity. We showed previously that growth factor-induced phosphorylation of PR Ser-294 blocks PR Lys-388 sumoylation. SUMO-deficient mutant PR-B (K388R) thus provides a model receptor for the study of PR function in the context of high kinase activities. T47D cells stably expressing K388R PR-B exhibited increased ligand-independent proliferation and growth in soft agar relative to cells expressing wt PR-B or phospho-mutant (sumoylated) S294A PR-B. Expression of selected PR target genes (HB-EGF, IRS-1, and STC1) was significantly elevated in cells containing desumoylated (K388R) PR-B. Basal PR transcriptional activity occurred independently of progestins, was increased by activated CDK2, and attenuated by RU486. Notably, ChIP assays demonstrated that K388R PR-B and SRC1 were constitutively recruited to the STC1 promoter in the absence of progestin; PR Lys-388 sumoylation was required for HDAC3 recruitment. Knock-down of STC1 inhibited proliferation of cells expressing K388R PR-B. These data suggest a mechanism whereby phosphorylated, and thus desumoylated, PRs mediate increased expression of growth promoting genes. Our data explain why breast cancer models often remain insensitive to progestins, but are growth-inhibited by antiprogestins, and underscore the need to target PR-B and associated kinase activities as part of breast cancer therapy.

Macartney-Coxson DP, Hood KA, Shi HJ, et al.
Metastatic susceptibility locus, an 8p hot-spot for tumour progression disrupted in colorectal liver metastases: 13 candidate genes examined at the DNA, mRNA and protein level.
BMC Cancer. 2008; 8:187 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Mortality from colorectal cancer is mainly due to metastatic liver disease. Improved understanding of the molecular events underlying metastasis is crucial for the development of new methods for early detection and treatment of colorectal cancer. Loss of chromosome 8p is frequently seen in colorectal cancer and implicated in later stage disease and metastasis, although a single metastasis suppressor gene has yet to be identified. We therefore examined 8p for genes involved in colorectal cancer progression.
METHODS: Loss of heterozygosity analyses were used to map genetic loss in colorectal liver metastases. Candidate genes in the region of loss were investigated in clinical samples from 44 patients, including 6 with matched colon normal, colon tumour and liver metastasis. We investigated gene disruption at the level of DNA, mRNA and protein using a combination of mutation, semi-quantitative real-time PCR, western blotting and immunohistochemical analyses.
RESULTS: We mapped a 2 Mb region of 8p21-22 with loss of heterozygosity in 73% of samples; 8/11 liver metastasis samples had loss which was not present in the corresponding matched primary colon tumour. 13 candidate genes were identified for further analysis. Both up and down-regulation of 8p21-22 gene expression was associated with metastasis. ADAMDEC1 mRNA and protein expression decreased during both tumourigenesis and tumour progression. Increased STC1 and LOXL2 mRNA expression occurred during tumourigenesis. Liver metastases with low DcR1/TNFRSF10C mRNA expression were more likely to present with extrahepatic metastases (p = 0.005). A novel germline truncating mutation of DR5/TNFRSF10B was identified, and DR4/TNFRSF10A SNP rs4872077 was associated with the development of liver metastases (p = 0.02).
CONCLUSION: Our data confirm that genes on 8p21-22 are dysregulated during colorectal cancer progression. Interestingly, however, instead of harbouring a single candidate colorectal metastasis suppressor 8p21-22 appears to be a hot-spot for tumour progression, encoding at least 13 genes with a putative role in carcinoma development. Thus, we propose that this region of 8p comprises a metastatic susceptibility locus involved in tumour progression whose disruption increases metastatic potential.

Raulic S, Ramos-Valdes Y, DiMattia GE
Stanniocalcin 2 expression is regulated by hormone signalling and negatively affects breast cancer cell viability in vitro.
J Endocrinol. 2008; 197(3):517-29 [PubMed] Related Publications
Stanniocalcin 1 (STC1) and STC2 are secreted, homodimeric glycoproteins that share 30% amino acid sequence identity. Breast tumour gene profiling studies have demonstrated significantly upregulated STC2 expression in hormone-responsive positive breast tumours; therefore, the purpose of this study was to investigate STC2 hormonal regulation and function in breast cancer cells. Here we report that STC2 is expressed in a number of human breast cancer cell lines, regardless of their oestrogen (E(2)) and progesterone (P4) receptor status, and its expression is readily detectable in human and mouse mammary gland tumours. Besides E(2), retinoic acid (RA) and P4 play an important role in the regulation of STC2 expression, not only in MCF-7 but also in other breast cancer and non-breast cell lines. The expression of the related hormone, STC1, is not affected by the above hormones in breast and endometrial cancer cell lines implying a fundamental difference in regulation in cancer cell lines. The induction of STC2 expression by E(2) and RA occurs at the transcriptional level but through intermediary transcription factors. The STC2 proximal promoter region is not responsible for hormonal induction, but exhibits a high basal transcriptional activity. Constitutive STC2 expression in human breast cancer cell lines resulted in significant impairment of cell growth, migration and cell viability after serum withdrawal. In conclusion, STC2 is a downstream target of E(2), P4 and RA signalling pathways. In hormone receptor negative cell lines it can function in a paracrine/autocrine fashion to reduce cell proliferation.

Pärssinen J, Alarmo EL, Khan S, et al.
Identification of differentially expressed genes after PPM1D silencing in breast cancer.
Cancer Lett. 2008; 259(1):61-70 [PubMed] Related Publications
Amplification and overexpression of PPM1D (protein phosphatase magnesium-dependent 1 delta) has been observed in various cancer cell lines and primary tumors and has also been associated with cancers of poor prognosis. In addition to the negative feedback regulation of p38-p53 signaling, PPM1D inhibits other tumor suppressor activities and is involved in the control of DNA damage and repair pathways. To elucidate the functional significance of PPM1D in breast cancer, we employed RNA interference to downregulate PPM1D expression in BT-474, MCF7, and ZR-75-1 breast cancer cell lines and then investigated the effects of PPM1D silencing on global gene expression patterns and signaling pathways using oligonucleotide microarrays. We identified 1798 differentially expressed (at least a two-fold change) gene elements with functions related to key cellular processes, such as regulation of cell cycle, assembly of various intracellular structures and components, and regulation of signaling pathways and metabolic cascades. For instance, genes involved in apoptosis (NR4A1, RAB25, PLK1), formation of nucleosome structure (HIST1H2AC, HIST1H2BF, HIST1H2BO, HIST1H1D), and hormone related activities (NR4A1, ESR1, STC1) were among the differentially expressed genes. Overall, our findings suggest that PPM1D contributes to breast cancer associated phenotypic characteristics by directly or indirectly affecting several important cellular signaling pathways.

Nakagawa T, Martinez SR, Goto Y, et al.
Detection of circulating tumor cells in early-stage breast cancer metastasis to axillary lymph nodes.
Clin Cancer Res. 2007; 13(14):4105-10 [PubMed] Related Publications
PURPOSE: Clinical and pathologic prognostic factors do not always accurately predict disease outcome. Patients with early-stage breast cancer may harbor clinically significant but undetected systemic disease. We hypothesized that a multimarker quantitative real-time reverse transcription-PCR (qRT) assay could detect circulating tumor cells (CTC) in patients with early-stage breast cancer and correlate with sentinel lymph node (SLN) and non-SLN metastasis status.
EXPERIMENTAL DESIGN: Blood samples from 90 women with the American Joint Committee on Cancer stages I to III breast cancer and 39 age-matched normal healthy volunteers were assessed by qRT for mRNA expression of three markers: stanniocalcin-1 (STC-1), N-acetylgalactosaminyltransferase (GalNacT), and melanoma antigen gene family-A3 (MAGE-A3). CTC biomarker detection was correlated with overall axillary LN (ALN), SLN, and non-SLN histopathology status.
RESULTS: CTCs were detected in 39 of 90 (43%) patients, but not in normal volunteers. At least one CTC biomarker was detected in 10 of 35 (29%) stage I patients, 19 of 42 (45%) stage II patients, and 10 of 13 (77%) stage III patients. In multivariate analysis, only lymphovascular invasion and >or=2 CTC biomarkers detected significantly correlated with ALN metastasis [odds ratio (OR), 12.42; 95% confidence interval (95% CI), 3.52-43.77, P<0.0001; and OR, 3.88; 95% CI, 1.69-8.89, P=0.001, respectively]. The number of CTC biomarkers detected similarly correlated with SLN and non-SLN metastasis status (P=0.0004). At least one CTC biomarker was detected in 10 of 11 (91%) patients with non-SLN metastases.
CONCLUSION: The detection of CTCs offers a novel means to assess the presence of systemic disease spreading relative to SLN and ALN histopathology status.

Lai KP, Law AY, Yeung HY, et al.
Induction of stanniocalcin-1 expression in apoptotic human nasopharyngeal cancer cells by p53.
Biochem Biophys Res Commun. 2007; 356(4):968-75 [PubMed] Related Publications
There is growing evidence to suggest that altered patterns of STC1 gene expression relate to the process of human cancer development. Our previous study has demonstrated the involvement of HIF-1 in the regulation of STC1 expression in human cancer cells. Recently, STC1 has been implicated as a putative pro-apoptotic factor in regulating the cell-death mechanism. Thus it would be of interest to know if STC1 is regulated by a tumor suppressor protein, p53. In this study, we provide evidence to demonstrate that the induction of STC1 expression in apoptotic human nasopharyngeal cancer cells (CNE2) is mediated by the activation of p53. Our study indicated that the activation of STC1 and heat-shock protein (hsp70) accompanied iodoacetamide (IDAM)-induced apoptosis in CNE-2. In addition, cellular events such as GSH depletion, mitochondrial membrane depolarization, reduction of pAkt and procaspase-3, and the induction of total p53 protein, acetylated p53, and annexin V positive cells were observed. The activation of STC1 was found to be at the transcriptional level and was independent of prior protein synthesis. Co-treatment of IDAM exposed cells with N-acetyl cysteine (NAC) prevented cell death by restoring mitochondrial membrane potential and cellular levels of GSH. NAC co-treatment also suppressed STC1 expression but had no effect on IDAM-induced hsp70 expression. RNA interference studies demonstrated that endogenous p53 was involved in activating STC1 gene expression. Collectively, the present findings provide the first evidence of p53 regulation of STC1 expression in human cancer cells.

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