calpain and Neoplasm-Metastasis

Metastatic dissemination represents the final stage of tumor progression as well as the principal cause of cancer-associated deaths. Calpains are a conserved family of calcium-dependent cysteine proteinases with ubiquitous or tissue-specific expression. Accumulating evidence indicates a central role for calpains in tumor migration and invasion via participating in several key processes, including focal adhesion dynamics, cytoskeletal remodeling, epithelial-to-mesenchymal transition, and apoptosis. Activated after the increased intracellular calcium concentration (

Topics: Apoptosis; Calcium; Calcium Signaling; Calpain; Cell Adhesion; Cell Movement; Cell Proliferation; Humans; Neoplasm Metastasis; Neoplasms

Hypoxia, through hypoxia inducible factor (HIF), drives cancer cell invasion and metastatic progression in various cancer types. In epithelial cancer, hypoxia induces the transition to amoeboid cancer cell dissemination, yet the molecular mechanisms, relevance for metastasis, and effective intervention to combat hypoxia-induced amoeboid reprogramming remain unclear. Here, we identify calpain-2 as a key regulator and anti-metastasis target of hypoxia-induced transition from collective to amoeboid dissemination of breast and head and neck (HN) carcinoma cells. Hypoxia-induced amoeboid dissemination occurred through low extracellular matrix (ECM)-adhesive, predominantly bleb-based amoeboid movement, which was maintained by a low-oxidative and -glycolytic energy metabolism ("eco-mode"). Hypoxia induced calpain-2-mediated amoeboid conversion by deactivating β1 integrins through enzymatic cleavage of the focal adhesion adaptor protein talin-1. Consequently, targeted downregulation or pharmacological inhibition of calpain-2 restored talin-1 integrity and β1 integrin engagement and reverted amoeboid to elongated phenotypes under hypoxia. Calpain-2 activity was required for hypoxia-induced amoeboid conversion in the orthotopic mouse dermis and upregulated in invasive HN tumor xenografts in vivo, and attenuation of calpain activity prevented hypoxia-induced metastasis to the lungs. This identifies the calpain-2/talin-1/β1 integrin axis as a druggable mechanosignaling program that conserves energy yet enables metastatic dissemination that can be reverted by interfering with calpain activity.

Topics: Animals; Calpain; Cell Line, Tumor; Cell Movement; Head and Neck Neoplasms; Humans; Hypoxia; Integrin beta1; Mice; Neoplasm Metastasis; Talin

Capn4, also known as CapnS1, is a member of the calpain family, which plays a crucial role in maintaining the activity and function of calpain. We previously reported that Capn4 also plays an essential role in the migration of nasopharyngeal carcinoma (NPC) cells through regulation of (MMP-2) by nuclear factor-kappa B activation. Epstein-Barr virus latent membrane protein 1 (LMP1) is closely related to the malignant functions of NPC; however, the relationship between LMP1 and Capn4 in NPC remain unclear. Immunohistochemical studies showed that the level of LMP1 and Capn4 expression was high in both primary and metastatic NPC tissues, with a significantly positive correlation. We further found that LMP1 was able to upregulate the Capn4 promoter in a dose-dependent way through the C-terminal activation region (CTAR)1 and CTAR2 domains to activate AP-1. Moreover, we also found that LMP1 activated AP-1 through ERK/JNK phosphorylation. These findings indicate that Capn4 coordination with LMP1 promotes actin rearrangement and, ultimately, cellular migration. These results show that Capn4 coordination with LMP1 enhances NPC migration by increasing actin rearrangement involving ERK/JNK/AP-1 signaling. Therapeutically, additional and more specific LMP1 and Capn4 targeted inhibitors could be exploited to treat NPC.

Topics: Calpain; Cell Line, Tumor; Epstein-Barr Virus Infections; Gene Expression Regulation, Neoplastic; Herpesvirus 4, Human; Humans; MAP Kinase Signaling System; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Metastasis; NF-kappa B; Phosphorylation; Promoter Regions, Genetic; Signal Transduction; Transcription Factor AP-1; Up-Regulation; Viral Matrix Proteins

Capn4, a small regulatory subunit of the calpain proteolytic system, functions as a potential tumor promoter in several cancers. However, the biological functions and molecular mechanisms of Capn4 in gastric cancer (GC) remain poorly understood. In the current study, we found that upregulation of Capn4 was detected frequently in GC tissues, and was associated with significantly worse survival among the GC patients. Multivariate analyses revealed that abundance of Capn4 was an independent predictive marker for the poor prognosis of GC. Further, Capn4 knockdown notably suppressed GC invasion and metastasis in vitro. Consistently, a xenograft assay showed that silencing of Capn4 in GC cells suppressed their dissemination to lung tissue in vivo. Moreover, our results indicated that Capn4 promotes gastric cancer metastasis by increasing MMP9 expression, and demonstrated that MMP9 is crucial for the pro-metastasis role of Capn4 in GC cells. Further investigation revealed that Capn4 regulated MMP9 expression via activation of Wnt/β-catenin signaling pathway. Mechanistically, we found that Capn4 can decreased β-catenin ubiquitination to enhance the protein stability of β-catenin in GC cells. Collectively, Capn4 has a central role in gastric cancer metastasis, which could be a potential diagnostic and therapeutic target for GC.

Topics: Calpain; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 9; Neoplasm Metastasis; Stomach Neoplasms; Up-Regulation; Wnt Signaling Pathway

Capn4 and ZEB1 play important roles in the metastasis of several types of cancer. However, the roles and relationship of Capn4 and ZEB1 in esophageal squamous cell carcinoma (ESCC) remain unclear.. ESCC tumor tissues and corresponding normal esophageal epithelial tissues were obtained from 86 patients undergoing resection surgery at the Department of General Surgery, First Affiliated Hospital of Chinese PLA General Hospital from 2012 to 2017. Cell migration and invasion were examined via quantitative real-time PCR and Western blot assay.. Our results indicate that both Capn4 and ZEB1 are significantly upregulated in ESCC tissues compared to corresponding adjacent tissues, and a positive correlation between expression and associated malignant characteristics was found. Silencing of Capn4 expression markedly inhibited ESCC invasion and metastasis in vitro and in vivo, and was accompanied by decreased ZEB1 expression. Furthermore, the anti-metastasis role of Capn4 silencing was reversed by ZEB1 overexpression, whereas knockdown of ZEB1 decreased ESCC metastasis driven by the upregulation of Capn4. Mechanistically, Capn4 regulated ZEB1 expression via activation of the Wnt/β-catenin signaling pathway in ESCC cells.. Overall, our results show that enhanced Capn4 expression activates the Wnt/β-catenin signaling pathway, resulting in increased ZEB1 expression and the promotion of ESCC cell metastasis.

Topics: Animals; Calpain; Cell Line, Tumor; Cell Movement; Cell Proliferation; Esophageal Squamous Cell Carcinoma; Gene Expression Regulation, Neoplastic; Humans; Mice; Neoplasm Metastasis; Wnt Signaling Pathway; Xenograft Model Antitumor Assays; Zinc Finger E-box-Binding Homeobox 1

Metastasis is the major cause of cancer-specific death in patients with prostate cancer (PCa). We previously reported that collapsing response mediator protein-4 (CRMP4) is a PCa metastasis-suppressor gene and the hypermethylation in CRMP4 promoter is responsible for the transcription repression in metastatic PCa. However, the underlying mechanisms remain unknown. In this study, we aimed to investigate the role of calpain-2 in CRMP4 promoter hypermethylation and its functional modulation in PCa metastasis.. Calpain-2 expression in PCa tissues (n = 87) and its specific mechanisms of functional modulation in CRMP4 expression via limited enzymatic cleavage was investigated. We then focused on the cooperative crosstalk of calpain-2 and NF-κB RelA/p65 in CRMP4 promoter methylation for the initiation of PCa metastasis. Statistical differences between groups were determined using a two-tailed Student's t-test. P < 0.05 indicated statistically significant.. Calpain-2 was differentially upregulated in metastatic PCa compared with localized PCa. Moreover, calpain-2 cleaved CRMP4 into the N-terminally fragment which promoted migration and invasion in PCa cells via nuclear translocation and activation of E2F1-mediated DNA methyltransferase 1 (DNMT1) expression. NF-κB RelA/p65 recruited DNMT1 to bind to and methylate CRMP4 promoter in which Serine276 phosphorylation of p65 was essential. Furthermore, CRMP4 exhibited anti-metastatic function via inhibiting the expression of VEGFC through Semaphorin3B-Neuropilin2 signaling.. Calpain-2 may contribute to the promoter methylation of CRMP4 to repress its transcription, leading to the metastasis of PCa via enhancing VEGFC expression.

Topics: Aged; Calpain; Cell Line, Tumor; CpG Islands; DNA (Cytosine-5-)-Methyltransferase 1; DNA Methylation; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; Male; Membrane Glycoproteins; Middle Aged; Muscle Proteins; Neoplasm Metastasis; Neuropilin-2; Phosphorylation; Promoter Regions, Genetic; Prostatic Hyperplasia; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Receptor Cross-Talk; Retrospective Studies; Semaphorins; Signal Transduction; Transcription Factor RelA; Up-Regulation; Vascular Endothelial Growth Factor C

Calpain small subunit 1 (Capn4) has been shown to correlate with the metastasis/invasion of clear cell renal cell carcinoma (ccRCC). This study aimed to further elucidate the molecular mechanisms underlying Capn4-mediated ccRCC progression. The mRNA expression levels in ccRCC cells were measured by quantitative real-time PCR. The effects of Capn4 on cell adhesion, invasion, and migration were examined by cell adhesion assay, cell invasion assay, and wound-healing assay, respectively. The protein levels were detected by western blot analysis. The effect of Capn4 on cancer metastasis in vivo was assessed in a nude mice xenograft model. It was found that Capn4 was up-regulated in the ccRCC cells, and Capn4 overexpression suppressed cell adhesion activity and increased cell invasion and migration in 786-O cells, while Capn4 silencing increased cell adhesion activity and impaired the invasion and migration ability of Caki-1 cells. Capn4 overexpression also increased the protein level of cleaved talin in 786-O cells, while Capn4 silencing decreased the protein level of cleaved talin in Caki-1 cells. The focal adhesion kinase (FAK)/AKT/MAPK signaling was activated by Capn4 overexpression in 786-O cells, and was inhibited by Capn4 down-regulation in Caki-1 cells. Capn4 overexpression increased the protein levels of matrix metalloproteinase 2 (MMP-2), vimentin, N-cadherin, and down-regulated E-cadherin in 786-O cells, while Capn4 silencing decreased the protein levels of MMP-2, vimentin, N-cadherin, and up-regulated E-cadherin in Caki-1 cells. Capn4 also promoted cancer metastasis in the in vivo nude mice xenograft model. Our results implicate the functional role of Capn4 in ccRCC invasion and migration, which may contribute to cancer metastasis in ccRCC.

Topics: Animals; Calpain; Carcinoma, Renal Cell; Cell Line; Cell Line, Tumor; Focal Adhesion Protein-Tyrosine Kinases; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Kidney Neoplasms; Mice, Nude; Neoplasm Invasiveness; Neoplasm Metastasis; Signal Transduction; Talin; Transplantation, Heterologous

The aim of this study was to explore whether LINC00657 can regulate cell proliferation and invasion by regulating the PI3K/AKT pathway and thus participate in the occurrence of colon cancer.. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was applied to detect the expression levels of LINC00657 and E-cad in colon cancer tissues and corresponding adjacent tissues obtained from 80 patients, and the correlation was analyzed between LINC00657 expression and clinical information of patients such as prognosis, tumor size, tumor stage, and distant metastasis. The expression of LINC00657 and E-cad in colon cancer cell lines was also examined, and the effect of LINC00657 on tumor cell proliferation was evaluated by cell counting kit-8 (CCK-8) assay and colony formation experiments. Meanwhile, transwell assay was performed to evaluate the influence of LINC00657 and CAPN7 on cell invasive ability. In addition, the effect of LINC00657 on CAPN7 and PI3K/AKT pathway was detected by Western blot assay.. The expression levels of LINC00657 and E-cad in tumor tissues decreased remarkably, especially in patients who occurred distant metastasis. Compared with patients with highly-expressed LINC00657, the patients with lower level of LINC00657 had a worse prognosis and an advanced tumor size and TNM stage. Similarly, LINC00657 and E-cad also showed a decrease in colon cancer cell lines. After overexpression of LINC00657, cell viability and invasive ability decreased remarkably while cell apoptosis rate increased significantly. In addition, high expression of LINC00657 in an in vitro model significantly promoted CAPN7 expression and inhibited activation of PI3K/AKT pathway.. LINC00657 had a low expression in colon cancer tissues, which could accelerate cell proliferation and invasion by activating PI3K/AKT pathway and inhibiting CAPN7 expression.

Topics: Caco-2 Cells; Calpain; Cell Line, Tumor; Cell Movement; Cell Proliferation; Colonic Neoplasms; Down-Regulation; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Staging; Phosphatidylinositol 3-Kinases; Prognosis; Proto-Oncogene Proteins c-akt; RNA, Long Noncoding; Signal Transduction

Renal cancer accounts for about 3% of human cancer, and clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cancer. Recently, microRNAs (miRNAs) are found to be the biomarkers for cancer diagnosis, prognosis and the targets for tumor management. This study aimed to examine the expression of miR-337-3p in ccRCC and to elucidate the molecular mechanisms underlying miR-337-3p-mediated ccRCC progression.. The miRNA and mRNA expression levels in ccRCC cells and tissues were measured by qRT-PCR. Cell proliferation, cell adhesion, colony growth and cell invasion were examined by CCK-8 assay, cell adhesion assay, colony formation assay and Transwell invasion assay, respectively. The protein levels were detected by western blot assay. The effects of miR-337-3p on tumor growth in vivo was assessed in a nude mice xenograft model.. MiR-337-3p was down-regulated in ccRCC cell lines, and miR-337-3p overexpression suppressed cell proliferation, colony growth and invasion, but enhanced cell adhesion in ccRCC; while knockdown of miR-337-3p exerted the opposite effects on ccRCC. Bioinformatics analysis and luciferase reporter assay showed that Calpain small subunit 1 (Capn4) was negatively regulated by miR-337-3p, and overexpression of miR-337-3p attenuated the miR-337-3p-mediated effects on ccRCC cellular functions. In addition, miR-337-3p also suppressed epithelial-mesenchymal transition in ccRCC. The in vivo tumor growth was markedly suppressed after miR-337-3p overexpression. Data from clinical data showed that down-regulation of miR-337-3p and up-regulation of Capn4 mRNA and protein were identified in the ccRCC tissues, and miR-337-3p expression level was inversely correlated with Capn4 mRNA expression level in ccRCC tissues.. Collectively, these data suggested the tumor suppressive role of miR-337-3p in ccRCC. MiR-337-3p suppressed cell proliferation and metastasis in ccRCC partially via targeting Capn4.

Topics: Animals; Biomarkers, Tumor; Calpain; Carcinoma, Renal Cell; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Mice; MicroRNAs; Neoplasm Metastasis; Xenograft Model Antitumor Assays

We have previously described a novel pathway controlling drug resistance, epithelial-to-mesenchymal transition (EMT) and stemness in breast cancer cells. Upstream in the pathway, three miRs (miR-106b, miR-93 and miR-25) target EP300, a transcriptional activator of E-cadherin. Upregulation of these miRs leads to the downregulation of EP300 and E-cadherin with initiation of an EMT. However, miRs regulate the expression of many genes, and the contribution to EMT by miR targets other than EP300 cannot be ruled out.. We used lentiviruses expressing EP300-targeting shRNA to downregulate its expression in MCF-7 cells as well as an EP300-knocked-out colon carcinoma cell line. An EP300-expression plasmid was used to upregulate its expression in basal-like CAL51 and MDA-MB-231 breast cancer cells. Drug resistance was determined by short-term proliferation and long-term colony formation assays. Stemness was determined by tumour sphere formation in both soft agar and liquid cultures as well as by the expression of CD44/CD24/ALDH markers. Gene expression microarray analysis was performed in MCF-7 cells lacking EP300. EP300 expression was analysed by immunohistochemistry in 17 samples of metaplastic breast cancer.. Cells lacking EP300 became more resistant to paclitaxel whereas EP300 overexpression increased their sensitivity to the drug. Expression of cancer stem cell markers, as well as tumour sphere formation, was also increased in EP300-depleted cells, and was diminished in EP300-overexpressing cells. The EP300-regulated gene signature highlighted genes associated with adhesion (CEACAM5), cytoskeletal remodelling (CAPN9), stemness (ABCG2), apoptosis (BCL2) and metastasis (TGFB2). Some genes in this signature were also validated in a previously generated EP300-depleted model of breast cancer using minimally transformed mammary epithelial cells. Importantly, two key genes in apoptosis and stemness, BCL2 and ABCG2, were also upregulated in EP300-knockout colon carcinoma cells and their paclitaxel-resistant derivatives. Immunohistochemical analysis demonstrated that EP300 expression was low in metaplastic breast cancer, a rare, but aggressive form of the disease with poor prognosis that is characterized by morphological and physiological features of EMT.. EP300 plays a major role in the reprogramming events, leading to a more malignant phenotype with the acquisition of drug resistance and cell plasticity, a characteristic of metaplastic breast cancer.

Topics: ATP Binding Cassette Transporter, Subfamily G, Member 2; Breast Neoplasms; Calpain; Carcinoembryonic Antigen; Cell Plasticity; Cell Proliferation; Drug Resistance, Neoplasm; E1A-Associated p300 Protein; Female; Gene Expression Regulation, Neoplastic; GPI-Linked Proteins; Humans; Lentivirus; MCF-7 Cells; Neoplasm Metastasis; Neoplasm Proteins; Neoplastic Stem Cells; Paclitaxel; Proto-Oncogene Proteins c-bcl-2; Transforming Growth Factor beta2

Increasing evidence shows that the calpain regulatory subunit Capn4 can modulate the proliferation and metastasis of cancer cells, and plays an important role in the development of malignant tumors. However, there is no information on the clinical significance of Capn4 in epithelial ovarian carcinoma (EOC) or the molecular mechanisms by which Capn4 promotes the growth and metastasis of EOC. Therefore, the aim of this study was to clarify the role of Capn4 in EOC.. We evaluated Capn4 and osteopontin (OPN) expression in EOC cell lines and tissues from patients with ovarian cancer by western blotting and immunohistochemical analysis. We then created cell lines with downregulated and upregulated Capn4 expression, using Capn4-targeting small interfering RNA and a pcDNA3.1-Capn4 overexpression vector, respectively, to investigate its function in EOC in vitro. In addition, we investigated the potential mechanism underlying the function of Capn4 by examining the effect of modifying Capn4 expression on Wnt/β-catenin signaling pathway-related genes by western blotting.. Capn4 was overexpressed in clinical EOC tissues compared with that in normal ovarian epithelial tissue, and was associated with poor clinical outcomes. Upon silencing or overexpressing Capn4 in EOC cells, we concluded that Capn4 promotes cell proliferation and migration in vitro. Furthermore, Capn4 promoted EOC metastasis by interacting with the Wnt/β-catenin signaling pathway to upregulate OPN expression.. Our study indicates that Capn4 plays a critical role in the progression and metastasis of EOC, and could be a potential therapeutic target for EOC management.

Topics: beta Catenin; Calpain; Carcinoma, Ovarian Epithelial; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Down-Regulation; Female; Humans; Immunohistochemistry; Kaplan-Meier Estimate; Middle Aged; Neoplasm Metastasis; Neoplasms, Glandular and Epithelial; Osteopontin; Ovarian Neoplasms; Plasmids; RNA Interference; RNA, Small Interfering; Up-Regulation; Wnt Proteins; Wnt Signaling Pathway

In patients with breast cancer and lung cancer, chymotrypsin-like and caspase-like activities of proteasomes and total activity of calpains in the primary tumor nodes and lymphogenic metastasis are elevated in comparison with the corresponding normal tissues. The development of lymphogenic metastases of breast cancer and lung cancer was associated with opposite change in caspase-like activity of proteasomes. These results can be useful for the development of methods for evaluation of aggressiveness of breast and lung cancer.

Topics: Adult; Breast Neoplasms; Calpain; Female; Humans; Lung Neoplasms; Middle Aged; Neoplasm Metastasis; Proteasome Endopeptidase Complex

Liver resection is still the most commonly used therapeutic treatment for hepatocellular carcinoma (HCC), and liver regeneration promotes HCC growth in the regenerating liver. The high recurrence/metastasis of HCC is the main cause of death for HCC patients after liver resection. However, how the augmented growth and metastasis of residual HCC induced by the promoted liver regeneration following liver resection can be abolished remains unclear. In this study, a rat model with liver cirrhosis and diffused HCC was established by administration of diethylnitrosamine. Recombinant miR-203 adenovirus was administered to induce hepatic miR-203 overexpression and 30% partial hepatectomy (PH) followed. The effect of miR-203 on the proliferation, invasion and metastasis of the residual HCC in the remnant cirrhotic liver with promoted regeneration was investigated. We found that the basic spontaneous regeneration of the non-tumorous liver by 30% PH promoted proliferation, invasion and lung metastasis of the hepatic residual HCC. miR-203 overexpression further promoted the regeneration of the non-tumorous liver by upregulating Ki67 expression and enhancing IL-6/SOCS3/STAT3 pro-proliferative signals. Importantly, miR-203 overexpression markedly inhibited the proliferation, invasion and metastasis of hepatic residual HCC through suppressing expression of Ki67, CAPNS1 and lung metastasis. Moreover, it was found that miR-203 overexpression reversed the epithelial-mesenchymal transition induced by hepatectomy through targeting IL-1β, Snail1 and Twist1. In conclusion, our results suggested that miR-203 overexpression inhibited the augmented proliferation and lung metastasis of the residual HCC induced by the promoted liver regeneration following PH partly by regulating epithelial-mesenchymal transition.

Topics: Animals; Calpain; Carcinoma, Hepatocellular; Cell Movement; Cell Proliferation; Diethylnitrosamine; Epithelial-Mesenchymal Transition; Hepatectomy; Interleukin-1beta; Interleukin-6; Ki-67 Antigen; Liver; Liver Neoplasms; Male; MicroRNAs; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Recurrence, Local; Rats; Rats, Wistar; Snail Family Transcription Factors; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 3 Protein; Twist-Related Protein 1

The chymotrypsin-like total proteasome activity and activity of 26S and 20S pools of proteasomes as well as calpain activitiy were found to be significantly increased in colon cancer tissue as compared to normal colon tissue. Patients with stage T2-4N1-3M0-lcolon cancer had higher activity level of the 26/20S proteasome and total calpain activities than patients with stage T2-4NOMO-1 colon cancer. The chymotrypsin-like total activity of proteasomes and the total activity of caplains in patients with stage T2-4N0-3M1 colon cancer were re- spectively 1.6 and 2.0-fold higher compared to those in patients with stage T2-4N0-3M0 colon cancer. Survival analysis of patients with colon cancer showed that the high level of chymotrypsin-like protesome activity in colon cancer and normal colon tissues (more than 72-1000 units/mg protein and 35-1000 units/mg protein, respectively) and the high level of total calpain activity in colon cancer and normal colon tissues (more than 100.5-1000 Units/mg protein and 52-1000 Units/ mg protein, respectively) were unfavorable factors in terms of 2-year metastasis-free survival.

Topics: Aged; Calpain; Colonic Neoplasms; Female; Humans; Male; Middle Aged; Neoplasm Metastasis; Neoplasm Proteins; Proteasome Endopeptidase Complex

Our previous study shows that Calpain 6 (CAPN6) expression is regulated by PI3K-Akt in liver cancer through POU2F1 and CAPN6 which promote cell proliferation and inhibit apoptosis of liver cancer cells. microRNAs (miRNAs) plays important roles in regulation of gene expression. However, whether miRNAs regulates CAPN6 expression and its cellular function is still unknown. This study aims to investigate how miRNAs regulate liver cancer apoptosis through POU2F1-CAPN6. It was verified that POU2F1 could promote cell proliferation and inhibit apoptosis through CAPN6. Using methods of bioinformatics, miR-449a was predicted as a potential regulator of both CAPN6 and POU2F1. It was verified that CAPN6 and POU2F1 were the target genes of miR-449a by luciferase assay. CAPN6 and POU2F1 protein and mRNA levels decreased in liver cancer cells with miR-449a overexpression using western blot and real time RT-PCR assays. miR-449a expression was lower in liver cancer tissues compared with their normal ones, so did the cells. Overexpression of miR-449a inhibited cell proliferation, induced G1 phase arrest and cell apoptosis in liver cancer. Further research demonstrated that miR-449a inhibited cancer cell proliferation and induced apoptosis via suppressing both POU2F1 and CAPN6. The study indicated that miR-449a functions as a tumor inhibitor in liver cancer by decreasing POU2F1 and CAPN6 expression in liver cancer.

Topics: Apoptosis; Biomarkers, Tumor; Calpain; Carcinoma, Hepatocellular; Cell Cycle; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Male; MicroRNAs; Microtubule-Associated Proteins; Middle Aged; Neoplasm Grading; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Staging; Octamer Transcription Factor-1; Prognosis; Signal Transduction; Survival Rate; Tumor Cells, Cultured

Calpain is an intracellular Ca(2+)-regulated protease system whose substrates include proteins involved in proliferation, survival, migration, invasion, and sensitivity to therapeutic drugs. Genetic disruption of calpain attenuated the tumorigenic potential of breast cancer cells and hypersensitized cells to 17AAG, an inhibitor of the molecular chaperone HSP90. Calpain-1 or -2 overexpression rendered cells resistant to 17AAG, whereas downregulation or inhibition of calpain-1/2 led to increased cell death in multiple breast cancer cell lines, including models of HER2(+) (SKBR3) and triple-negative basal-cell-like (MDA-MB-231) breast cancer. In an MDA-MB-231 orthotopic xenograft model, calpain knockdown or 17AAG treatment independently attenuated tumor growth and metastasis, while the combination was most effective. Calpain knockdown was associated with increased 17AAG-induced degradation of the HSP90 clients cyclin D1 and AKT and multidrug resistance protein 2, which correlated with increased expression of antimitogenic p27(KIP1) and proapoptotic BIM proteins. Like other therapeutics, 17AAG can be effluxed by specific ABC transporters. Calpain expression positively correlated with the expression of P glycoprotein in mouse embryonic fibroblasts. Importantly, we show that calpain affects ABC transporter function and efflux of clinically relevant doxorubicin. These observations provide a compelling rationale for exploring the combination of calpain inhibition with new or existing cancer therapeutics.

Topics: Animals; Benzoquinones; Breast Neoplasms; Calpain; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Combined Modality Therapy; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lactams, Macrocyclic; Mice; Neoplasm Metastasis; Xenograft Model Antitumor Assays

Activation of Epithelial-to-Mesenchymal Transition (EMT) is important for tumor metastasis. Although growth factors such as TGFβ and EGF have been shown to induce EMT in breast epithelial cells, the mechanism resulting in migration is not well understood. Herein, we provide evidence that Ca2+ entry into the cell, especially upon store-depletion, plays an important role in TGFβ-induced EMT by promoting cellular migration and potentially leading to metastasis. The increased migration by TGFβ in non-cancerous cells was due to the loss of E-cadherin along with a subsequent increase in N-cadherin levels. Importantly, TGFβ-treatment increases store-mediated Ca2+ entry, which was essential for the activation of calpain leading to the loss of E-cadherin and MMP activation. Inhibition of Ca2+ entry by using Ca2+ channel blocker SKF-96365, significantly decreased Ca2+ entry, decreased TGFβ-induced calpain activation, and suppressed the loss of E-cadherin along with inhibiting cell migration. Furthermore, TRPC1 function as an endogenous Ca2+ entry channel and silencing of either TRPC1 or its activator, STIM1, significantly decreased TGFβ induced Ca2+ entry, inhibited TGFβ-mediated calpain activation and cell migration. In contrast, overexpression of TRPC1 showed increased Ca2+ entry and promoted TGFβ-mediated cell migration. Moreover, increased TRPC1 expression was observed in ductal carcinoma cells. Together these results suggest that disrupting Ca2+ influx via TRPC1/STIM1 mechanism reduces calpain activity, which could restore intercellular junction proteins thereby inhibiting EMT induced motility.

Topics: Antigens, CD; Breast Neoplasms; Cadherins; Calcium Signaling; Calpain; Cell Line, Tumor; Cell Movement; Epithelial-Mesenchymal Transition; Female; Humans; Matrix Metalloproteinases; Membrane Potentials; Neoplasm Metastasis; Neoplasm Proteins; RNA Interference; Stromal Interaction Molecule 1; Time Factors; Transfection; Transforming Growth Factor beta; TRPC Cation Channels

Upon activation by its ligand hepatocyte growth factor/scatter factor, the receptor tyrosine kinase Met promotes survival, proliferation, and migration of epithelial cells during embryogenesis. Deregulated Met signaling can also promote cancer progression and metastasis. Met belongs to the functional family of dependence receptors whose activity switches from pro-survival to pro-apoptotic during apoptosis upon caspase cleavage. Although apoptosis resistance is a hallmark of cancer cells, some remain sensitive to other cell death processes, including necrosis induced by calcium stress. The role and fate of Met during necrotic cell death are unknown. Following treatment with calcium ionophores, cell lines and primary cells undergo necrosis, and the full-length Met receptor is efficiently degraded. This degradation is achieved by double cleavage of Met in its extracellular domain by a metalloprotease of the A disintegrin and metalloproteinase (ADAM) family and in its intracellular domain by calpains (calcium-dependent proteases). These cleavages separate the Met extracellular region from its kinase domain, thus preventing Met activity and its potential pro-survival activity. Although the intracellular fragment is very similar to the fragment generated by caspases, it displays no pro-apoptotic property, likely because of the presence of the last few amino acids of Met, known to inhibit this pro-apoptotic function. The fragments identified here are observed in lung tumors overexpressing the Met receptor, along with fragments previously identified, suggesting that proteolytic cleavages of Met are involved in its degradation in tumor tissues. Thus, Met is a modulator of necrosis, able to protect cells when activated by its ligand but efficiently degraded by proteolysis when this process is engaged.

Topics: ADAM Proteins; Animals; Apoptosis; Calcium; Calpain; Caspases; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Enzyme Activation; Epithelial Cells; HEK293 Cells; Hepatocyte Growth Factor; Humans; Ionomycin; Lung Neoplasms; Mice; Necrosis; Neoplasm Metastasis; Proto-Oncogene Proteins c-met; RNA Interference; RNA, Small Interfering; Signal Transduction

Up-regulation of the cytoskeleton linker protein ezrin frequently occurs in aggressive cancer types and is closely linked with metastatic progression. However, the underlying molecular mechanisms detailing how ezrin is involved in the invasive and metastatic phenotype remain unclear. Here we report a novel function of ezrin in regulating focal adhesion (FA) and invadopodia dynamics, two key processes required for efficient invasion to occur. We show that depletion of ezrin expression in invasive breast cancer cells impairs both FA and invadopodia turnover. We also demonstrate that ezrin-depleted cells display reduced calpain-mediated cleavage of the FA and invadopodia-associated proteins talin, focal adhesion kinase (FAK), and cortactin and reduced calpain-1-specific membrane localization, suggesting a requirement for ezrin in maintaining proper localization and activity of calpain-1. Furthermore, we show that ezrin is required for cell directionality, early lung seeding, and distant organ colonization but not primary tumor growth. Collectively our results unveil a novel mechanism by which ezrin regulates breast cancer cell invasion and metastasis.

Topics: Animals; Breast Neoplasms; Calpain; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cytoskeletal Proteins; Cytoskeleton; Extracellular Matrix; Female; Focal Adhesion Protein-Tyrosine Kinases; Focal Adhesions; HEK293 Cells; Heterografts; Human Umbilical Vein Endothelial Cells; Humans; Mice; Neoplasm Metastasis; Podosomes; Talin

Calpain small subunit 1 (Capn4) plays a key role in tumor migration or invasion. In this study, expression and function of Capn4 was investigated in human nasopharyngeal carcinoma (NPC). Here we report that both mRNA and protein levels of Capn4 were elevated in NPC tissues when compared to normal NP tissues. Similarly, Capn4 was also highly expressed in multiple NPC cell lines, compared to immortalized human nasopharyngeal epithelial cell line NP69. Moreover, expression of Capn4 was significantly correlated with Epstein-Barr virus infection, advanced stages, and lymph node or distant metastasis (P < 0.001). The patients with NPC displaying higher Capn4 had a significantly shorter overall survival (P = 0.002) and progression-free survival (P = 0.003). Furthermore, siRNA knockdown of Capn4 suppressed cell migration and invasion in vitro and in vivo. These events resulted from Capn4 downregulation were associated with reduced expression of matrix metalloproteinase 2 (MMP2), Snail, and Vimentin. Finally, we demonstrated that Capn4 upregulated MMP2 via nuclear factor-κB (NF-κB) activation, manifested by increased phosphorylation of p65, a subunit of NF-κB. Together, these findings argue a novel function of Capn4 in invasion and metastasis of NPC, and thereby suggest that Capn4 may represent an independent prognostic factor and a potential therapeutic target in NPC.

Topics: Animals; Biomarkers, Tumor; Cadherins; Calpain; Carcinoma; Cell Line, Tumor; Cell Movement; Disease-Free Survival; Enzyme Activation; Epstein-Barr Virus Infections; Female; Focal Adhesions; Gene Expression Regulation, Neoplastic; Humans; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphorylation; RNA Interference; RNA, Messenger; RNA, Small Interfering; Snail Family Transcription Factors; Transcription Factor RelA; Transcription Factors; Vimentin

Senescent cells accumulate in aged tissue and are causally linked to age-associated tissue degeneration. These non-dividing, metabolically active cells are highly secretory and alter tissue homeostasis, creating an environment conducive to metastatic disease progression. IL-1α is a key senescence-associated (SA) proinflammatory cytokine that acts as a critical upstream regulator of the SA secretory phenotype (SASP). We established that SA shifts in steady-state H2O2 and intracellular Ca(2+) levels caused an increase in IL-1α expression and processing. The increase in intracellular Ca(2+) promoted calpain activation and increased the proteolytic cleavage of IL-1α. Antioxidants and low oxygen tension prevented SA IL-1α expression and restricted expression of SASP components IL-6 and IL-8. Ca(2+) chelation or calpain inhibition prevented SA processing of IL-1α and its ability to induce downstream cytokine expression. Conditioned medium from senescent cells treated with antioxidants or Ca(2+) chelators or cultured in low oxygen markedly reduced the invasive capacity of proximal metastatic cancer cells. In this paracrine fashion, senescent cells promoted invasion by inducing an epithelial-mesenchymal transition, actin reorganization, and cellular polarization of neighboring cancer cells. Collectively, these findings demonstrate how SA alterations in the redox state and Ca(2+) homeostasis modulate the inflammatory phenotype through the regulation of the SASP initiator IL-1α, creating a microenvironment permissive to tumor invasion.

Topics: Calcium; Calcium Signaling; Calpain; Cell Line, Tumor; Cellular Senescence; Enzyme Activation; Epithelial-Mesenchymal Transition; Humans; Hydrogen Peroxide; Interleukin-1alpha; Interleukin-6; Interleukin-8; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Proteins; Neoplasms; Oxidants; Oxidation-Reduction; Paracrine Communication; Proteolysis; Tumor Microenvironment

Osteopontin (OPN) is a secreted phosphoprotein, originally characterized in malignant-transformed epithelial cells. OPN is associated with tumor metastasis of several tumors and is overexpressed in hepatocellular carcinoma (HCC) tissue involving HCC invasion and metastasis. Importantly, OPN is significantly up-regulated in liver injury, inflammation, and hepatitis C virus (HCV)-associated HCC. However, the underlying mechanisms of OPN activation and its role in HCV-mediated liver disease pathogenesis are not known. In this study, we investigated the mechanism of OPN activation in HCV-infected cells. We demonstrate that HCV-mediated Ca(2+) signaling, elevation of reactive oxygen species, and activation of cellular kinases such as p38 MAPK, JNK, PI3K, and MEK1/2 are involved in OPN activation. Incubation of HCV-infected cells with the inhibitors of AP-1 and Sp1 and site-directed mutagenesis of AP-1- and Sp1-binding sites on the OPN promoter suggest the critical role of AP-1 and Sp1 in OPN promoter activation. In addition, we show the in vivo interactions of AP-1 and Sp1 with the OPN promoter using chromatin immunoprecipitation assay. We also show the calpain-mediated processing of precursor OPN (∼75 kDa) into ∼55-, ∼42-, and ∼36-kDa forms of OPN in HCV-infected cells. Furthermore, we demonstrate the critical role of HCV-induced OPN in increased phosphorylation of Akt and GSK-3β followed by the activation of β-catenin, which can lead to EMT of hepatocytes. Taken together, these studies provide an insight into the mechanisms of OPN activation that is relevant to the metastasis of HCV-associated HCC.

Topics: beta Catenin; Calcium Signaling; Calpain; Carcinoma, Hepatocellular; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Extracellular Signal-Regulated MAP Kinases; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hepacivirus; Hepatitis C; Hepatocytes; Humans; Liver Neoplasms; Neoplasm Metastasis; Osteopontin; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Sp1 Transcription Factor; Transcription Factor AP-1

The genesis and unique properties of the lymphovascular tumor embolus are poorly understood largely because of the absence of an experimental model that specifically reflects this important step of tumor progression. The lymphovascular tumor embolus is a blastocyst-like structure resistant to chemotherapy, efficient at metastasis and overexpressing E-cadherin (E-cad). Conventional dogma has regarded E-cad as a metastasis-suppressor gene involved in epithelial-mesenchymal transition. However, within the lymphovascular embolus, E-cad and its proteolytic processing by calpain and other proteases have a dominant oncogenic rather than suppressive role in metastasis formation and tumor cell survival. Studies using a human xenograft model of inflammatory breast cancer, MARY-X, demonstrated the equivalence of xenograft-generated spheroids with lymphovascular emboli in vivo with both structures demonstrating E-cad overexpression and specific proteolytic processing. Western blot revealed full-length (FL) E-cad (120 kDa) and four fragments: E-cad/NTF1 (100 kDa), E-cad/NTF2 (95 kDa), E-cad/NTF3 (85 kDa) and E-cad/NTF4 (80 kDa). Compared with MARY-X, only E-cad/NTF1 was present in the spheroids. E-cad/NTF1 was produced by calpain, E-cad/NTF2 by γ-secretase and E-cad/NTF3 by a matrix metalloproteinase (MMP). Spheroidgenesis and lymphovascular emboli formation are the direct result of calpain-mediated cleavage of E-cad and the generation of E-cad/NTF1 from membrane-associated E-cad rather than the de novo presence of either E-cad/NTF1 or E-cad/CTF1. E-cad/NTF1 retained the p120ctn-binding site but lost both the β-catenin and α-binding sites, facilitating its disassembly from traditional cadherin-based adherens junctions and its 360° distribution around the embolus. This calpain-mediated proteolysis of E-cad generates the formation of the lymphovascular embolus and is responsible for its unique properties of increased homotypic adhesion, apoptosis resistance and budding.

Topics: Amino Acid Sequence; Animals; Blood Vessels; Cadherins; Calpain; Carcinoma; Cell Adhesion; Cell Line, Tumor; Cell Survival; Embolism; Female; Humans; Inflammatory Breast Neoplasms; Lymphatic Vessels; Models, Biological; Molecular Sequence Data; Neoplasm Metastasis; Neoplasms; Neovascularization, Pathologic; Proteolysis; Transplantation, Heterologous

Directional migration of adherent cells on an extracellular matrix requires repeated formation and disassembly of focal adhesions (FAs). Directional migration of adherent cells We have identified ZF21 as a regulator of disassembly of FAs and cell migration, and increased expression of the gene has been linked to metastatic colon cancer. ZF21 is a member of a protein family characterized by the presence of the FYVE domain, which is conserved among Fab1p, YOPB, Vps27p, and EEA1 proteins, and has been shown to mediate the binding of such proteins to phosphoinositides in the lipid layers of cell membranes. ZF21 binds multiple factors that promote disassembly of FAs such as FAK, β-tubulin, m-calpain, and SHP-2. ZF21 does not contain any other known protein motifs other than the FYVE domain, but a region of the protein C-terminal to the FYVE domain is sufficient to mediate binding to β-tubulin. In this study, we demonstrate that the C-terminal region is important for the ability of ZF21 to induce disassembly of FAs and cell migration, and to promote an early step of experimental metastasis to the lung in mice. In light of the importance of the C-terminal region, we analyzed its ternary structure using NMR spectroscopy. We demonstrate that this region exhibits a structure similar to that of a canonical pleckstrin homology domain, but that it lacks a positively charged interface to bind phosphatidylinositol phosphate. Thus, ZF21 contains a novel noncanonical PH-like domain that is a possible target to develop a therapeutic strategy to treat metastatic cancer.

Topics: Amino Acid Motifs; Animals; Calpain; Carrier Proteins; Cell Line; Cell Movement; Focal Adhesion Kinase 1; Focal Adhesions; Humans; Integrin beta1; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Mice; Neoplasm Metastasis; Neoplasms; Phosphorylation; Protein Tyrosine Phosphatases

Liver transplantation (LT) is one of the best therapeutic options for nonresectable hepatocellular carcinoma (HCC). Unfortunately, some HCC patients succumb to the disease after LT, which reduces long- and medium-term survival. To identify the proteins associated with HCC invasion and metastasis, HCC patients undergoing LT with complete follow-up data were included in this study and were categorized into recurrence and nonrecurrence groups. We extracted the total protein from the acquired homogeneous tumor cells and applied a cleavable isotope-coded affinity tag technology to quantitate relative changes in protein levels between the two groups. We identified a total of 149 proteins with two-dimensional liquid chromatography coupled with tandem mass spectrometry, including 52 differentially expressed proteins by at least two-fold. Among them, calpain small subunit 1 (Capn4), a protein with relevant interactions with many migration-invasion-related proteins, has attracted more attention. First, Capn4 overexpression in the recurrence group was confirmed via real-time polymerase chain reaction and western blotting in another cohort of 40 HCC patients undergoing LT. Second, Capn4 was associated with enhanced invasiveness in vitro. The small interfering RNA-mediated knockdown expression of Capn4 in HCC cell lines significantly inhibited its mobile and invasive ability. Tissue microarray in a further 192 cases revealed that Capn4 significantly correlated with invasive phenotype of HCC, and univariate and multivariate analyses indicated that Capn4 is an independent prognostic factor for recurrence and survival of HCC patients.. Our study revealed that Capn4 overexpression underlies invasion and metastasis after LT for HCC and might be a candidate biomarker for future diagnosis and a target for therapy.

Topics: Calpain; Carcinoma, Hepatocellular; China; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Liver Transplantation; Neoplasm Invasiveness; Neoplasm Metastasis; Oligonucleotide Array Sequence Analysis; Polymerase Chain Reaction; Prognosis; Proteome; RNA, Neoplasm; RNA, Small Interfering

Caspase-8 is a proapoptotic protease that suppresses neuroblastoma metastasis by inducing programmed cell death. Paradoxically, caspase-8 can also promote cell migration among nonapoptotic cells; here, we show that caspase-8 can promote metastasis when apoptosis is compromised. Migration is enhanced by caspase-8 recruitment to the cellular migration machinery following integrin ligation. Caspase-8 catalytic activity is not required for caspase-8-enhanced cell migration; rather, caspase-8 interacts with a multiprotein complex that can include focal adhesion kinase and calpain 2 (CPN2), enhancing cleavage of focal adhesion substrates and cell migration. Caspase-8 association with CPN2/calpastatin disrupts calpastatin-mediated inhibition of CPN2. In vivo, knockdown of either caspase-8 or CPN2 disrupts metastasis among apoptosis-resistant tumors. This unexpected molecular collaboration provides an explanation for the continued or elevated expression of caspase-8 observed in many tumors.

Topics: Alstrom Syndrome; Animals; Calcium-Binding Proteins; Calpain; Caspase 8; Cell Line, Tumor; Cell Movement; Focal Adhesion Protein-Tyrosine Kinases; Focal Adhesions; Humans; Lung Neoplasms; Mice; Mice, Transgenic; Neoplasm Metastasis; Neuroblastoma; Talin

Calpains are cysteine proteases comprising members ubiquitously expressed in human tissues and other tissue-specific isoforms. Alterations of calpain 3 (p94), the muscle-specific isoform that contains three peculiar sequences (NS, IS1 and IS2), are strictly associated to the limb-girdle muscular dystrophy type 2A, in which a myonuclear apoptosis has been documented. Our recent demonstration of a proapoptotic role of ubiquitous calpains in drug-induced apoptosis of melanoma cells prompted us to investigate the expression of calpain 3 in human melanoma cell lines undergoing apoptosis and in melanocytic lesions. In melanoma cell lines, we have identified two novel splicing variants of calpain 3 (hMp78 and hMp84): they have an atypical initiation exon and a putative nuclear localization signal, the shorter one lacks IS1 inset and both proteins are extremely unstable. Virtually, both isoforms (prevalently as cleavage forms) are localized in cytoplasm and in nucleoli. In cisplatin-treated preapoptotic cells, an increase of both transcription and autoproteolytic cleavage of the novel variants is observed; the latter event is prevented by the inhibitor of ubiquitous calpains, calpeptin, which is also able to protect from apoptosis. Interestingly, among melanocytic lesions, the expression of these novel variants is significantly downregulated, compared with benign nevi, in the most aggressive ones, i.e. in vertical growth phase melanoma and, even more, in metastatic melanoma cells, characterized by invasiveness properties and usually highly resistant to apoptosis. On the whole, our observations suggest that calpain 3 variants can play a proapoptotic role in melanoma cells and its downregulation, as observed in highly aggressive lesions, could contribute to melanoma progression.

Topics: Alternative Splicing; Antineoplastic Agents; Apoptosis; Biopsy; Calpain; Cell Line, Tumor; Cell Nucleolus; Cisplatin; Cytoplasm; Dipeptides; Dysplastic Nevus Syndrome; Gene Expression Regulation, Neoplastic; Humans; Melanoma; Muscle Proteins; Neoplasm Metastasis; Nevus; RNA, Messenger; Skin Neoplasms

Osteosarcoma, the most common primary bone tumor in young adults, is characterized by local invasion and distant metastasis. But detailed mechanisms of tumorigenicity and metastasis of osteosarcoma are not well known. We report the involvement of calpains, a family of calcium-activated, cysteine proteases, in the invasive and metastatic processes of human osteosarcoma cells. By using siRNA treatment, the expression of mu- and m-calpains were downregulated in human Saos-2 osteosarcoma cells. Both the adhesive and invasive potentials were significantly attenuated in calpain siRNA-transfected human Saos-2 osteosarcoma cells. MMPs are the main factors involved in malignant tumor invasion and metastasis. siRNA of calpains also significantly inhibited the secretion of MMP-2 in Saos-2 cells. These results suggest that mu- and m-calpains are important in the invasion and metastasis of human osteosarcoma cells, and calpains might be targeted to reduce tumor progression.

Topics: Calpain; Cell Adhesion; Cell Line, Tumor; Chemotaxis; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Matrix Metalloproteinases; Neoplasm Invasiveness; Neoplasm Metastasis; Osteosarcoma; RNA, Small Interfering

Overexpression of cyclin E in breast tumors is associated with a poor response to tamoxifen therapy, greater genomic instability, more aggressive behavior, and a poor clinical prognosis. These tumors also express low molecular weight isoforms of cyclin E that are associated with higher kinase activity and increased metastatic potential. In the current study, we show that cyclin E overexpression in MCF7 cells transactivates the expression of calpain 2, leading to proteolysis of cyclin E as well as several known calpain substrates including focal adhesion kinase (FAK), calpastatin, pp60src, and p53. In vivo inhibition of calpain activity in MCF7-cyclin E cells impedes cyclin E proteolysis, whereas in vivo induction of calpain activity promotes cyclin E proteolysis. An analysis of human breast tumors shows that high levels of cyclin E are coincident with the expression of the low molecular weight isoforms, high levels of calpain 2 protein, and proteolysis of FAK. Lastly, studies using a mouse model of metastasis reveal that highly metastatic tumors express proteolyzed cyclin E and FAK when compared to tumors with a low metastatic potential. Our results suggest that cyclin E-dependent deregulation of calpain may be pivotal in modifying multiple cellular processes that are instrumental in the etiology and progression of breast cancer.

Topics: Animals; Breast Neoplasms; Calpain; Cell Line, Tumor; Cyclin E; Focal Adhesion Protein-Tyrosine Kinases; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Isoenzymes; Mice; Neoplasm Metastasis; Transcriptional Activation; Transfection

Mounting evidence indicates that cigarette smoking not only promotes tumorigenesis but also may increase the spread of cancer cells in the body. However, the intracellular mechanism(s) by which cigarette smoking promotes metastasis of human lung cancer remains enigmatic. Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is an important component in cigarette smoke and is formed by nitrosation of nicotine. mu- and m-calpain (calpain I and calpain II) are major members of the calpain family, which are ubiquitously expressed in both small cell lung cancer and non-small cell lung cancer cells. Our findings indicated that NNK potently induces phosphorylation of both mu- and m-calpain in association with their activation and increased migration as well as invasion of lung cancer cells. Treatment of cells with PD98059 blocked phosphorylation of m- and mu-calpain and resulted in suppression of NNK-induced cell migration and invasion. p44 MAPK/extracellular signal-regulated kinase 1 (ERK1) and p42 MAPK/ERK2 were activated by NNK, co-localized with mu- and m-calpain in cytoplasm, and directly phosphorylated mu- and m-calpain in vitro. These findings suggest a role for the ERK1/2 kinases as NNK-activated physiological calpain kinases. Specific knock-down of mu- and/or m-calpain expression by RNA interference blocked NNK-stimulated migration and invasion, suggesting that mu- and m-calpain may act as required targets in a NNK-induced metastatic signaling pathway. Furthermore, NNK promotes secretion of active mu- and m-calpain from lung cancer cells through vesicles, which may have the potential to cleave substrates in the extracellular matrix. Thus, NNK-induced cell migration and invasion may occur, at least in part, through a novel mechanism involving phosphorylation of calpains that leads to their activation and secretion, which may contribute to metastasis and/or progression of lung cancer.

Topics: Blotting, Western; Calpain; Carcinogens; Cell Line, Tumor; Cell Movement; Disease Progression; Dose-Response Relationship, Drug; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Flavonoids; Gene Silencing; Genetic Vectors; Humans; Immunoprecipitation; Lung Neoplasms; Microscopy, Fluorescence; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Models, Biological; Neoplasm Invasiveness; Neoplasm Metastasis; Nicotiana; Nitrosamines; Phosphorylation; RNA Interference; RNA, Small Interfering; Signal Transduction