Decreased expression of carbonyl reductase 1 promotes ovarian cancer growth and proliferation

Overexpression of carbonyl reductase 1 in ovarian cancer cells suppresses proliferation and activates the eIF2 signaling pathway

High expression of carbonyl reductase 1 (CBR1) protein in ovarian cancer cells inhibits tumor growth and metastasis. However, the underlying mechanism is unknown. To investigate the mechanism by which CBR1 suppresses tumor growth, the present study generated ovarian cancer cells that constitutively overexpress human CBR1 (hCBR1) protein. Ovarian cancer cell lines (OVCAR-3 and SK-OV-3) were transfected with a plasmid encoding hCBR1, followed by selection with G418 to isolate hCBR1-overexpressing lines. The proliferation rates of hCBR1-overexpressing cells were then compared with those of negative control and wild-type cells. Overexpression of hCBR1 led to significant inhibition of proliferation (P<0.05). Subsequently, to investigate changes in intracellular signaling pathways, cellular proteins were extracted and subjected to proteome analysis using liquid chromatography followed by mass spectrometry. There was an inverse correlation between CBR1 protein expression and cell proliferation. In addition, Ingenuity Pathway Analysis of hCBR1-overexpressing cell lines was performed, which revealed changes in the expression of proteins involved in signaling pathways related to growth regulation. Of these, the eukaryotic translation initiation factor 2 (eIF2) signaling pathway was upregulated most prominently. Thus, alterations in multiple tumor-related signaling pathways, including eIF2 signaling, may lead to growth suppression. Taken together, the present data may lead to the development of new drugs that target CBR1 and related signaling pathways, thereby improving outcomes for patients with ovarian cancer.

Development of transgenic mice overexpressing mouse carbonyl reductase 1

BACKGROUND

Carbonyl reductase 1 (CBR1) is a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductase with broad substrate specificity. CBR1 catalyzes the reduction of numerous carbonyl compounds, including quinones, prostaglandins, menadione, and multiple xenobiotics, while also participating in various cellular processes, such as carcinogenesis, apoptosis, signal transduction, and drug resistance. In this study, we aimed to generate transgenic mice overexpressing mouse Cbr1 (mCbr1), characterize the mCbr1 expression in different organs, and identify changes in protein expression patterns.

METHODS AND RESULTS

To facilitate a deeper understanding of the functions of CBR1, we generated transgenic mice overexpressing CBR1 throughout the body. These transgenic mice overexpress 3xFLAG-tagged mCbr1 (3xFLAG-mCbr1) under the CAG promoter. Two lines of transgenic mice were generated, one with 3xFLAG-mCbr1 expression in multiple tissues, and the other, with specific expression of 3xFLAG-mCbr1 in the heart. Pathway and network analysis using transgenic mouse hearts identified 73 proteins with levels of expression correlating with mCbr1 overexpression. The expression of voltage-gated anion channels, which may be directly related to calcium ion-related myocardial contraction, was also upregulated.

CONCLUSION

mCbr1 transgenic mice may be useful for further in vivo analyses of the molecular mechanisms regulated by Cbr1; such analyses will provide a better understanding of its effects on carcinogenesis and cardiotoxicity of certain cancer drugs.

Prostanoid Signaling in Cancers: Expression and Regulation Patterns of Enzymes and Receptors

Cancer-associated disturbance of prostanoid signaling provides an aberrant accumulation of prostanoids. This signaling consists of 19 target genes, encoding metabolic enzymes and G-protein-coupled receptors, and prostanoids (prostacyclin, thromboxane, and prostaglandins E2, F2α, D2, H2). The study addresses the systems biology analysis of target genes in 24 solid tumors using a data mining pipeline. We analyzed differential expression patterns of genes and proteins, promoter methylation status as well as tissue-specific master regulators and microRNAs. Tumor types were clustered into several groups according to gene expression patterns. Target genes were characterized as low mutated in tumors, with the exception of melanoma. We found at least six ubiquitin ligases and eight protein kinases that post-translationally modified the most connected proteins PTGES3 and PTGIS. Models of regulation of PTGIS and PTGIR gene expression in lung and uterine cancers were suggested. For the first time, we found associations between the patient’s overall survival rates with nine multigene transcriptomics signatures in eight tumors. Expression patterns of each of the six target genes have predictive value with respect to cytostatic therapy response. One of the consequences of the study is an assumption of prostanoid-dependent (or independent) tumor phenotypes. Thus, pharmacologic targeting the prostanoid signaling could be a probable additional anticancer strategy.

Host tissue proteomics reveal insights into the molecular basis of Schistosoma haematobium-induced bladder pathology

Urogenital schistosomiasis remains a major public health concern worldwide. In response to egg deposition, the host bladder undergoes gross and molecular morphological changes relevant for disease manifestation. However, limited mechanistic studies to date imply that the molecular mechanisms underlying pathology are not well-defined. We leveraged a mouse model of urogenital schistosomiasis to perform for the first time, proteome profiling of the early molecular events that occur in the bladder after exposure to S. haematobium eggs, and to elucidate the protein pathways involved in urogenital schistosomiasis-induced pathology. Purified S. haematobium eggs or control vehicle were microinjected into the bladder walls of mice. Mice were sacrificed seven days post-injection and bladder proteins isolated and processed for proteome profiling using mass spectrometry. We demonstrate that biological processes including carcinogenesis, immune and inflammatory responses, increased protein translation or turnover, oxidative stress responses, reduced cell adhesion and epithelial barrier integrity, and increased glucose metabolism were significantly enriched in S. haematobium infection. S. haematobium egg deposition in the bladder results in significant changes in proteins and pathways that play a role in pathology. Our findings highlight the potential bladder protein indicators for host-parasite interplay and provide new insights into the complex dynamics of pathology and characteristic bladder tissue changes in urogenital schistosomiasis. The findings will be relevant for development of improved interventions for disease control.

Chrysin induces autophagy-dependent ferroptosis to increase chemosensitivity to gemcitabine by targeting CBR1 in pancreatic cancer cells

Recent studies have verified that inducing reactive oxygen species (ROS) is one of the gemcitabine anti-tumor mechanisms of action. Human carbonyl reductase 1 (CBR1) plays an important role in protecting cells against oxidative damage. However, it is unclear whether CBR1 is involved in pancreatic cancer (PC) progression and resistance to gemcitabine. Based on the GEPIA database, we analyzed tumor tissue samples from PC patients using immunohistochemistry (IHC) and revealed that CBR1 was highly expressed in PC tissues and that this was significantly correlated with the clinicopathological features of PC. Genetic inhibition of CBR1 suppressed PC cell proliferation by regulating ROS generation. Furthermore, gemcitabine upregulated CBR1 expression, which could limit the anti-tumor activity of gemcitabine, and attenuation of CBR1 enhanced gemcitabine sensitivity in vitro and in vivo. Additionally, we report that chrysin directly binds to CBR1, which inhibited its enzymatic activity both at the molecular and cellular levels. Inhibition of CBR1 by chrysin increased cellular ROS levels and led to ROS-dependent autophagy, which resulted in the degradation of ferritin heavy polypeptide 1 (FTH1) and an increase in the intracellular free iron level that participates in ferroptosis in PC cells. Finally, our results showed that chrysin enhanced PC sensitivity to gemcitabine by inducing ferroptotic death in vitro and in vivo. Collectively, these findings indicate that CBR1 is a potential therapeutic target for PC treatment. In addition, we elucidated a novel mechanism underlying the anti-tumor effects of chrysin.

Genotype Analysis of ABCC1, NCF4 and CBR3 Polymorphism and the Association With Childhood Acute Lymphoblastic Leukemia in Mexican Childhood Population

Background: The identification of genetic risk factors for Acute Lymphoblastic Leukemia (ALL), are increasingly urgent and necessary. Objective: The purpose of this study is to determine the association of the genetic polymorphisms ABCC1 rs3743527, NCF4 rs1883112 and CBR3 rs1056892 with ALL. Methods: DNA samples were obtained in 71 children with ALL (from 2 to 18 years) and in 71 controls without ALL, to determine the polymorphisms by real-time polymerase chain reaction (qPCR), using specific TaqMan probes in a StepOne^® thermal cycler (Applied Biosystems, United States). Results: The results of the Odds Ratio analysis show that in the rs1883112 polymorphism of the NCF4 gene, the heterozygous allele has a risk effect for ALL (OR = 3.1870, CI = 1.8880-7.9383 and p = 0.0002), in turn the mutated genotype (AA) is associated with a protective effect (OR = 0.26, 0.1248 to 0.5434 and p = 0.0003). On the other hand, the CBR3 rs1056892 polymorphism shows a significant association of risk to ALL, in the presence of the HT genotype (OR = 2.77, IC = 1.3837 to 5.5651 and p = 0.004) and the mutated genotype of this polymorphism has a significant association with protection to ALL in the HM genotype (OR = 0.52, IC = 0.2639 to 1.0304 and p = 0.05). While the inheritance models of the polymorphisms let us see that of the rs1883112 polymorphism of the NCF4 polymorphism; the HT genotype of the codominant model shows a protective effect against ALL (OR = 0.4117, IC = 0.1718 to 0.9866 and p = 0.04), the recessive model shows us and confirms what we already saw in table number 3, being that there is an association with protective effect in the HM genotype (OR = 0.2604, IC = 0.1248 to 0.5434 and p = 0.0003). In the polymorphism rs1056892 of the CBR3 gene, a protection association was found in the heterozygous allele of the codominant model (OR = 0.3448, IC = 0.1375 to 0.8896 and p = 0.0274). In addition, the recessive inheritance model for the HM genotype shows a protective effect to ALL, (OR = 0.52, CI = 0.9919 to 3.8638 and p = 0.05). Conclusion: There is an evident impact of the NCF4 rs1883112 and CBR3 rs1056892 polymorphisms with an increased risk of susceptibility to ALL; Likewise, through the codominant inheritance model, the effect of the variation of the CBR3 rs1056892 gene as a protective factor against ALL was evaluated.

Inhibition of Carbonyl Reductase 1 Enhances Metastasis of Head and Neck Squamous Cell Carcinoma through β-catenin-Mediated Epithelial-Mesenchymal Transition

Objective: Human carbonyl reductase 1 (CBR1) plays key roles in the regulation of oxidative stress and tumor progression. However, the detailed mechanism and clinical correlation between CBR1 and tumor progression in head and neck squamous cell carcinoma (HNSCC) is largely unexplored. This study will focus the effects of CBR1 on head and neck cancer progression and explore the possible mechanisms.

Materials and Methods:CBR1 mRNA expression was analyzed according to lymph node metastasis (LNM) status in patients with HNSCC from publicly available databases. CBR1 protein levels were measured and compared in HNSCC patient tissues, with or without metastasis, using immunohistochemistry (IHC). The invasive ability of HNSCC with modulated CBR1 expression was assayed using an invasion assay. Expression levels of EMT marker proteins were analyzed using immunoblotting.

Results: HNSCC patients with LNM showed lower expression of CBR1 than those without LNM. In addition, IHC in tissues indicated that patients with LNM had relatively lower levels of CBR1 in cancer tissue. Consistently, in vitro invasion assay, we found that CBR1 inhibition using specific short interfering RNA treatment resulted in two- to three-fold increased invasion ability of HNSCC cell lines. Also, we proved that depletion of CBR1 activated marker proteins participating in epithelial-mesenchymal transition (EMT) signaling. CBR1 inhibition increased levels of intracellular reactive oxygen species (ROS) in HNSCC cells leading to upregulation of β-catenin, one of main transcription factors that induce EMT-related genes.

Conclusion: Our findings suggested that CBR1 plays an important role in metastasis of HNSCC tumors via regulation of ROS-mediated β-catenin activity, and that CBR1 may be marker for progression of HNSCC to metastasis.

Proteomic characterization of primary cultured myocytes in a fish model at different myogenesis stages

Myogenesis is a complex two-phase process of proliferation and differentiation, which seems to be greatly conserved in vertebrates. For the first time in fish, we identify the changes that occur in the proteome during this process in a gilthead sea bream (Sparus aurata) myocyte primary cell culture (on days 4, 8 and 12), using 2-D gel electrophoresis and LC-MS/MS. A significant increase of myogenin expression at day 8 marked the transition from proliferation to differentiation. Of the 898 spots in the proteome analysis, the 25 protein spots overexpressed on day 4 and the 15 protein spots overexpressed on day 8 indicate the end of proliferation and the beginning of differentiation, respectively. Proliferation was characterized by enrichment of proteins involved in actin cytoskeleton remodelling and in cellular metabolic processes (transcription, ubiquitination, response to stress and glucose metabolism). During differentiation, 41 proteins were overexpressed and 51 underexpressed; many of them related to biosynthetic processes (RNA and protein synthesis and folding, and pentose pathways), terminal myotube formation and muscle contraction. The main cellular processes of both phases of muscle development in fish are similar with those observed in mammals but extended in time, allowing sequential studies of myogenesis.

Expression profile analysis of prognostic long non-coding RNA in adult acute myeloid leukemia by weighted gene co-expression network analysis (WGCNA)

Background: Long non-coding RNAs (lncRNAs), which are over 200 nt in length, have a key role in tumorigenesis and disease progression. To explore the role of prognostic lncRNAs in adult acute myeloid leukemia (AML), the expression profiles of lncRNAs and mRNAs in AML were analyzed. Methods: The RNAseq data of 167 adult AML patients and the corresponding clinical information were downloaded from The Cancer Genome Atlas (TCGA), which is a publicly available database. The RPKM values of the RNAseq data were subjected to weighted gene co-expression network analysis (WGCNA) in modularization. Results: We identified survival specific lncRNAs and mRNAs, which were divided into modules by coexpression analysis. The lncRNAs were mainly annotated into "Fc gamma R-mediated phagocytosis". The hub lncRNA and co-expressed mRNAs were further selected for analysis of risk stratification. LncRNA-LOC646762 may contribute to AML through the "endocytosis" signaling pathway. Finally, the expression levels of LOC646762 and co-expressed CCND3, CBR1, C10orf54, CD97 and BLOC1S1 in the adult AML patients and healthy volunteers were validated by qRT-PCR, and then their roles in prognosis and risk stratification were identified. Conclusions: Prognostic lncRNA-LOC646762, which may contribute to AML through the "endocytosis" signaling pathway, may act as a biomarker for predicting the survival of adult AML patients, as well as for risk stratification.

Overexpression of carbonyl reductase 1 inhibits malignant behaviors and epithelial mesenchymal transition by suppressing TGF-β signaling in uterine leiomyosarcoma cells

Carbonyl reductase 1 (CBR1) has been reported to be involved in cancer progression. Recently, we found that CBR1 overexpression inhibited malignant behaviors and the epithelial mesenchymal transition (EMT) in uterine cervical cancer. It remained unclear whether this was also the case in uterine leiomyosarcoma (uLMS), which is derived from mesenchymal cells and is a much more malignant gynecological tumor. A number of previous studies suggested that malignant behaviors are associated with EMT, even in mesenchymal malignant tumors. In the present study, we investigated whether CBR1 inhibits malignant behaviors and EMT in uLMS. We established clones of uLMS cells (SKN cells) and uterine sarcoma cells (MES-SA cells) that overexpressed CBR1. Cell proliferative, migratory and invasive activities were suppressed by CBR1 overexpression, accompanied by increases in the expressions of epithelial markers (E-cadherin and cytokeratin) and decreases in the expressions of mesenchymal markers (N-cadherin and fibronectin), suggesting that CBR1 overexpression inhibits malignant behaviors and EMT in uLMS cells. In addition, transforming growth factor-β (TGF-β) production and the subsequent signaling and phosphorylation of Smad were suppressed in the clones. To investigate the association between TGF-β and EMT, SKN cells were treated with TGF-β or a TGF-β receptor blocker (SB431542). EMT was promoted by TGF-β and inhibited by SB431542. In conclusion, this is the first study, to the best of the authors' knowledge, showing that CBR1 overexpression inhibits malignant behaviors and EMT in uLMS cells. The present study provided novel insight demonstrating that the suppressive effect of CBR1 is mediated through TGF-β signaling.

Inhibitory effect of carbonyl reductase 1 against peritoneal progression of ovarian cancer: evaluation by ex vivo 3D-human peritoneal model

The current authors previously reported that a carbonyl reductase 1 (CR1) DNA-dendrimer complex could potentially be used in gene therapy for peritoneal metastasis of ovarian cancer. The aims of the current study were to observe the cellular dynamics of peritoneal metastasis of epithelial ovarian cancer cells and to ascertain changes in the dynamics of ovarian cancer cells as a result of transfection of CR1 DNA. (1) Artificial human peritoneal tissue (AHPT) was seeded with serous ovarian cancer cells, and the process leading to development of peritoneal carcinomatosis was observed over time. (2) Peritoneal carcinomatosis was produced in mice and compared to a model using AHPT to determine the appropriateness of AHPT. (3) CR1 DNA was transfected into cancer cells seeded on AHPT, and the dynamics of cancer cells were observed over time. (1) Cancer cells perforated the mesothelium, leaving normal mesothelium intact. However, the cells proliferated between the layers of the mesothelium, forming a mass. After 24 h, cancer cells had invaded the lymphatics, and after 48-72 h cancer cells had invaded deep into the mesothelium, where they formed a mass. (2) Invasion of the peritoneum by cancer cells in a murine model of peritoneal carcinomatosis resembled that in a model using AHPT, and results substantiated the reproducibility of peritoneal carcinomatosis in AHPT. (3) Proliferation of cells transfected with CR1 DNA was significantly inhibited on AHPT, and necrosis was evident. Nevertheless, cancer cell invasion deep into the mesothelium was not inhibited. Use of a new tool, AHPT, in an in vitro model of peritoneal metastasis revealed that CR1 DNA inhibited cancer cell proliferation. CR1 DNA does not play a role in inhibiting invasion of the mesothelium during peritoneal metastasis, but it does affect cancer cell proliferation. Results suggested that CR1 DNA inhibits cancer cell proliferation via necrosis.

Low carbonyl reductase 1 expression is associated with poor prognosis in patients with oral squamous cell carcinoma

Carbonyl reductase 1 (CBR1) is an enzyme that catalyzes the reduction of numerous compounds by using NADPH-dependent oxidoreductase activity. Decreased expression of CBR1 is associated with disease progression and an unfavorable outcome in several types of malignancies. The purpose of the current study was to determine whether CBR1 expression could be a useful prognostic factor in patients with oral squamous cell carcinoma (OSCC). Therefore, its mechanisms of action were investigated in order to understand how CBR1 affects cancer cell behavior in vitro. CBR1 expression was evaluated using immunohistochemistry and tissue samples obtained from 90 patients with OSCC. The associations between CBR1 expression, clinicopathological characteristics and patient survival were also analyzed. In addition, the role of CBR1 in cancer cell invasion and metastasis was examined, along with its underlying molecular mechanisms, via transfecting CBR1-siRNA into the HSC2 human OSCC cell line. Immunohistochemical analysis revealed that biopsy tissue samples of 71.1% of the patients with OSCC were positive for CBR1. In addition, CBR1 expression status was correlated with the N classification (P<0.0001), stage (P=0.0018) and outcome (P=0.0095). Furthermore, a statistical correlation was determined between the protein expression status and overall survival (P=0.0171). In vitro studies indicated that the suppression of CBR1 by CBR1-siRNA increased cancer cell proliferative, wound healing and migratory abilities. These findings suggest that low expression levels of CBR1 may affect cancer prognosis, and that CBR1 may have potential as a prognostic factor for patients with OSCC.

The metabolism of flubendazole in human liver and cancer cell lines

Flubendazole (FLU), a benzimidazole anthelmintic drug widely used in veterinary medicine, has been approved for the treatment of gut-residing nematodes in humans. In addition, FLU is now considered a promising anti-cancer agent. Despite this, information about biotransformation of this compound in human is lacking. Moreover, there is no information regarding whether cancer cells are able to metabolize FLU in order to deactivate it. For these reasons, the present study was designed to identify all metabolites of Phase I and Phase II of FLU in human liver and in various cancer cells using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Precision-cut human liver slices and 9 cell lines of different origin (breast, colon, oral cavity) were used as in vitro model systems. Our study showed that FLU with a reduced carbonyl group (FLUR) is the only FLU metabolite formed in the human liver. All human cancer cell lines were able to form FLUR. In addition, methylated FLUR was detected in breast cells MCF7 and intestinal SW480 cells. The accumulation of FLU and its reduction to FLUR markedly differed among cells. The extent of FLU reduction was in a good correlation with the detected expression level of carbonyl reductase 1. In most cases, FLU entered in a higher amount and was reduced to a lesser extent in proliferating (metastatic) cells than in differentiated (non-cancerous, non-metastatic) ones. These results support the promising potential of FLU in anti-cancer therapy.

Decreased carbonyl reductase 1 expression promotes tumor growth via epithelial mesenchymal transition in uterine cervical squamous cell carcinomas

Purpose

Carbonyl reductase 1 (CBR1) is involved in cancer progression. Recently, the authors reported that the loss of CBR1 expression is associated with a poor prognosis in uterine cervical cancer. Here, we investigated whether the decreased CBR1 expression promotes cancer progression by inducing the epithelial mesenchymal transition (EMT).

Methods

Antisense constructs of CBR1 complementary DNA (antisense clones) and the empty vectors (control clones) were transfected into human uterine cervical squamous cell carcinoma cell lines (SKG II and SiHa) and the proliferation and EMT marker expression of these clones were analyzed in vitro. In an in vivo study, 10⁷ cells of the antisense and control clones were subcutaneously injected into nude mice and the tumorigenesis was observed for 8 weeks.

Results

With the decreased CBR1 expression, the proliferation of the antisense clones increased, accompanied by a decrease in epithelial markers (E-cadherin and cytokeratin) and an increase in mesenchymal markers (fibronectin, alpha-smooth muscle actin, and N-cadherin), which suggests EMT induction. In the in vivo study, the tumor volume in the antisense group was significantly larger than that in the control group.

Conclusion

Decreased CBR1 expression promotes tumor growth by inducing EMT in uterine cervical squamous cell carcinomas.

Functional role of the Tau protein in epithelial ovarian cancer cells

Aim

The microtubule‐associated Tau protein is a marker of paclitaxel sensitivity in ovarian cancer. The aim of the present study was to elucidate the function of the Tau protein in epithelial ovarian cancer.

Methods

The correlation between Tau protein expression and the response to paclitaxel by using several ovarian cancer cell lines was investigated.

Results

A Western blot showed that the expression level of the Tau protein was the highest in the TOV112D cells. A cell‐counting kit showed that the proliferation rates were more inhibited in the cells with down‐regulated Tau protein than in the control cells, both with and without paclitaxel treatment. The proliferation rates of the control cells and the TOV112D cells also were compared with Tau protein overexpression. The level of cell proliferation was more inhibited in the cells that overexpressed the Tau protein, compared to the control cells, both with and without paclitaxel treatment. It was shown that both the down‐regulation and the overexpression of the Tau protein were related to the inhibition of TOV112D cell proliferation. Early and late apoptosis of the TOV112D cells that were transfected with Tau cDNA plasmid construct or Tau small interfering RNA significantly increased.

Conclusion

These findings suggest that the molecular targeting of the Tau protein could be a potential treatment for ovarian cancer.

Gene therapy for ovarian cancer using carbonyl reductase 1 DNA with a polyamidoamine dendrimer in mouse models

Ovarian cancer (OC) in which carbonyl reductase 1 (CBR1) is highly expressed has good prognosis. The aims of this study were to determine the optimal conditions for delivering CBR1 DNA to OC cells via a polyamidoamine (PAMAM) dendrimer and to examine the therapeutic effectiveness of using a CBR1/PAMAM dendrimer to treat OC. The ratio for mixture of the PAMAM dendrimer and CBR1 plasmid DNA was defined as the ratio of the number of moles of phosphate groups in plasmid DNA to the number of moles of amino groups in PAMAM, which was expressed as N/P ratio. Mice were intraperitoneally injected with OC cells (HRA) to create peritoneal carcinomatosis. CBR1 DNA/PAMAM dendrimer complexes were administered on alternate days after injection of HRA cells. Cells transfected with CBR1 DNA at N/P ratio of 20:1 for 48 h produced the highest level of CBR1 expression. All the mice in control group died prior to day 25. However, all the mice administered the CBR1 DNA/PAMAM dendrimer survived (P<0.001). Use of a PAMAM dendrimer allowed CBR1 DNA to be delivered to cancer cells. The results suggested that CBR1 DNA/PAMAM dendrimer complexes may represent a potent gene therapy for the treatment of advanced OC.

Inhibitory effect of carbonyl reductase 1 on ovarian cancer growth via tumor necrosis factor receptor signaling

We investigated the mechanisms of the inhibitory effect of carbonyl reductase 1 (CR1) on ovarian cancer growth mediated by the activation of the tumor necrotic factor receptor (TNFR) pathway. OVCAR-3 and TOV21G cells overexpressing CR1 were constructed by transfecting them with CR1 cDNA by lipofection. CR1-overexpressing and control OVCAR-3 and TOV21G cells were injected subcutaneously into nude mice and the tumor growth was compared between the two groups for 3-4 weeks. The expression of TNFR1 and TNFR2 in tumors was examined immunohistochemically at the end of the experiment. Expression levels of caspase-8 and -3 activated by TNFR1, c-Jun activated by TNFR2, and NF-κB activated by both TNFR1 and TNFR2 were determined using immunohistochemistry and western blot analysis. Tumor growth was significantly suppressed in mice injected with CR1-overexpressing cells. Tumor volume in the CR1 induction group decreased temporarily until 2 weeks. Tumor cell membranes in both CR1 induction and control groups were positive for TNFR1 expression; however, total protein levels did not differ between the two groups. TNFR-2 expression was comparatively weak in both groups. The expression of NF-κB and c-Jun was weaker in the CR1 induction group than in control. In contrast, caspase-8 and -3 expression was higher in the CR1 induction group. Furthermore, the number of apoptotic cells was significantly greater in tumors that appeared after injections of both types of CR1-overexpressing cells than in those of control cancer cells. These results suggest that CR1 induces apoptosis by activating the caspase pathway via binding to TNFR1.