Identification of specific nuclear structural protein alterations in human breast cancer

A novel lncRNA derived from an ultraconserved region: lnc-uc.147, a potential biomarker in luminal A breast cancer

The human genome contains 481 ultraconserved regions (UCRs), which are genomic stretches of over 200 base pairs conserved among human, rat, and mouse. The majority of these regions are transcriptionally active (T-UCRs), and several have been found to be differentially expressed in tumours. Some T-UCRs have been functionally characterized, but of those few have been associated to breast cancer (BC). Using TCGA data, we found 302 T-UCRs related to clinical features in BC: 43% were associated with molecular subtypes, 36% with oestrogen-receptor positivity, 17% with HER2 expression, 12% with stage, and 10% with overall survival. The expression levels of 12 T-UCRs were further analysed in a cohort of 82 Brazilian BC patients using RT-qPCR. We found that uc.147 is high expressed in luminal A and B patients. For luminal A, a subtype usually associated with better prognosis, high uc.147 expression was associated with a poor prognosis and suggested as an independent prognostic factor. The lncRNA from uc.147 (lnc-uc.147) is located in the nucleus. Northern blotting results show that uc.147 is a 2,8 kb monoexonic trancript, and its sequence was confirmed by RACE. The silencing of uc.147 increases apoptosis, arrests cell cycle, and reduces cell viability and colony formation in BC cell lines. Additionally, we identifed 19 proteins that interact with lnc-uc.147 through mass spectrometry and demonstrated a high correlation of lnc-uc.147 with the neighbour gene expression and miR-18 and miR-190b. This is the first study to analyse the expression of all T-UCRs in BC and to functionally assess the lnc-uc.147.

Lentivirus-mediated shRNA Targeting CNN2 Inhibits Hepatocarcinoma in Vitro and in Vivo

Objective: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high rate of mortality. Our previous study shows the expression of calponin 2 (CNN2) is up-regulated in hepatocellular carcinoma tissues, especially in metastatic ones. To better understand the role of CNN2 in HCC, RNA interference (RNAi) was used to explore its role in tumor growth and metastasis. Methods: Lentivirus-mediated CNN2-shRNA was transfected into SK-hep-1 cells, and the efficacy of CNN2 expression, cell migration, invasion, proliferation and cell cycles were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), Transwell assay, methyl thiazol tetrazolium assay and flow cytometry, respectively. SK-hep-1 cells transfected with Lentivirus-CNN2 shRNA were xenografted in Balb/C nude mice to explore the effect of CNN2-shRNA in tumor growth. Xenograft tumor tissues were examined for their histopathology, cell apoptosis, the expression of total protein and their corresponding phosphorylated protein of MEK1/2, ERK1/2, AKT, by hematoxylin and eosin stain (H & E staining), TUNEL assay, immunohistochemical technique, respectively. Results: Our research shows it is evident that CNN2 shRNA can effectively down-regulate the expressions of CNN2 mRNA and protein, inhibit cell proliferations, arrest cell cycles at the S phase and reduce cell migration and invasion. SK-hep-1 cells with CNN2 down-regulation have markedly attenuated tumor growth in nude mice. Xenograft tumor tissues have displayed typical tumor characteristics and no apoptosis is detected in shRNA group or in control group. No metastatic tumor was found in any group of nude mice. With CNN2 protein down-regulation, the protein of pMEK1/2 and pERK1/2 are effectively down-regulated, except pAKT, AKT, MEK1/2 and ERK1/2. Conclusions: CNN2 plays an important role in tumor growth and metastasis, possibly through MEK1/2-ERK1/2 signaling pathway. Our study illustrate that CNN2 might be a potential target in HCC molecular target therapy.

Calponin-h2 is upregulated in the tissues and plasma of patients with breast cancer

Increasing evidence has demonstrated that changes in plasma nuclear matrix proteins are specific markers of cancer. Furthermore, proteomic analysis has revealed that calponin-h2 is upregulated in human breast cancer tissue, but is absent in healthy and benign controls. However, the roles of levels of plasma calponin-h2 in the diagnosis of breast cancer and its association with clinicopathological parameters remain to be elucidated. In the present study, the plasma levels of calponin-h2 in patients with breast cancer, benign breast disease and in healthy controls were examined using an enzyme-linked immunosorbent assay. The expression levels of calponin-h2 in invasive breast cancer and normal breast tissues were measured using immunohistochemistry. Statistical analyses examined the association between the levels of plasma calponin-h2 and clinicopathological parameters. The results demonstrated that the plasma level of calponin-h2 in breast cancer was significantly higher than those in the healthy control and benign breast disease groups (P<0.05). The combination of calponin-h2, carcinoembryonic antigen, carbohydrate antigen 15-3 improved the diagnosis of breast cancer. The plasma levels of calponin-h2 PR-breast cancers was significantly higher, compared with PR+ breast cancers (P=0.033), and the plasma levels of calponin-h2 in patients with breast cancer aged >50 years was significantly higher than in patients ≤ 50 years of age (P=0.001). No association was found between the level of plasma calponin-h2 and other clinicopathological parameters of breast cancer. Taken together, these results indicated that calponin-h2 may be a useful marker of breast cancer.

Calponin-h2: a potential serum marker for the early detection of human breast cancer?

Early diagnosis is the key for the successful treatment of breast cancer. A serum marker for the early detection of breast cancer could significantly reduce breast cancer morbidity and mortality by bringing the time of diagnosis at an earlier and therefore still curable stage. So far, no biomarker for the early detection is available for the clinical routine. The aim of the present study was to evaluate the use of calponin-h2 as a blood-based biomarker for the early diagnosis of this disease. Using two monoclonal antibodies against calponin-h2, we developed a sandwich ELISA to analyze the serum levels of calponin-h2. In order to evaluate the diagnostic potential of this biomarker, patients with breast cancer (n = 76), benign diseases of the breast (n = 51) and healthy females (n = 24) were analyzed. Serum levels above 10 ng/ml were only observed in patients with breast cancer (n = 8; 10.5%). Further large-scale studies and preanalytic evaluations are necessary to clarify the definite role of calponin-h2 as a biomarker in breast cancer management.

Specific expression of k63-linked ubiquitination of calmodulin-like protein 5 in breast cancer of premenopausal patients

PURPOSE

Posttranslational modifications such as ubiquitination regulate many functions of proteins by affecting their interaction with other molecules, their activity, and their subcellular localization. In cancer biology, the ubiquitin network has gained major interest. K63-linked ubiquitination has emerged as a posttranslational modification with functional consequences, as it acts in several processes such as protein trafficking, DNA repair, and inflammation. Moreover, k63-linked ubiquitination is involved in the regulation of carcinogenesis. Based on previous findings, the aim of this study was to evaluate the ubiquitination of CALML5 in breast cancer patients.

PATIENTS AND METHODS

The breast cancer cell lines SkBr3, MCF7, HCC1937, and BT474 as well as 23 tumor samples of patients with primary breast cancer and the normal adjacent breast tissue were analyzed by one-dimensional immunoblot.

RESULTS

Using specific antibodies against CALML5 and k63-linked ubiquitin, we demonstrate a k63-linked ubiquitination in the nuclear fraction of premenopausal breast cancer patients. K63-linked ubiquitination of CALML5 was found in breast cancer tissue, but not found in surrounding healthy tissue.

CONCLUSION

Our findings support the concept that ubiquitination of CALML5 in the nucleus is involved in the carcinogenesis of breast cancer in premenopausal women.