Heterogeneous nuclear ribonucleoprotein M promotes the progression of breast cancer by regulating the axin/β-catenin signaling pathway

Despite significant progress in the treatment of breast cancer due to advances in surgery, cytotoxic agents, and endocrine therapy, the prognosis for patients has not improved much. Accumulated evidence indicates that heterogeneous nuclear ribonucleoprotein M (hnRNPM) and Wnt/β-catenin function as tumor oncogenes in the progression of many cancers. The present study aimed to explore whether HnRNPM/β-catenin signaling molecules might serve as a genetic target for breast cancer treatment. To shed light on this issue, quantitative real-time polymerase chain reaction (qRT-PCR) detection, Western blotting, and immunohistochemical staining were performed. The hnRNPM is expressed at a much higher level in breast cancer tissues and cell lines than in noncancerous tissues and cell lines. In vitro studies revealed that overexpressed hnRNPM promoted cell proliferation and colony formation but inhibited cell apoptosis. In vivo results demonstrated that upregulation of hnRNPM dramatically increased breast cancer xenograft tumor growth. Western blotting and immunofluorescence studies revealed that hnRNPM markedly activated the Wnt/β-catenin pathway and catalyzed its translocation from the cytoplasm to the nucleus by targeting axin, a negative regulator of Wnt/β-catenin signaling in MCF-7 and KPL-4 cells. Elevated levels of c-Myc and cyclin D1 were observed when MCF-7 and KPL-4 cells were transfected with a hnRNPM vector. These findings indicate that the hnRNPM/axin/β-catenin signaling pathway acts as an oncogenic promoter in the progression of breast cancer, suggesting that hnRNPM may be a potential target for the treatment of this disease.

Association between transforming growth factor-β1 expression and the clinical features of triple negative breast cancer

The aim of the present study was to investigate the association between the expression levels of transforming growth factor-β1 (TGF-β1) and the clinical pathological characteristics and prognosis of triple negative breast cancer (TNBC) through study of TNBC patient tissue samples. The biological effects of TGF-β1 on TNBC cells and the potential signal transduction pathway are additoinally investigated. Immunohistochemistry was utilized to investigate expression changes of the positive rate of TGF-β1 in the TNBC, compared with the non-TNBC group, to explain the association between TGF-β1 and clinical pathological characteristics and prognosis. MDA-MB-231 cells were treated with TGF-β1 and subsequently the invasion and migration abilities, and the expression of proteins in certain signaling pathways were assessed before and after the treatment. Positive expression of TGF-β1 was observed in 52.5% of TNBC tissue samples, which was higher than that observed in non-TNBC group (27.5%). High levels of TGF-β1 expression were not significantly associated age, menopausal status, family history of cancer or tumor size; however, tumor histological grade and axillary lymph node metastasis were significantly associated (P<0.05). In addition, when the TGF-β1 expression levels are higher, the 5-year disease-free survival rate is lower. TGF-β1 expression promoted the invasion and migration of MDA-MB-231 cells, and the expression of Smad2 protein and P38 protein was increased, indicating that Smad2 protein and the P38 signaling pathway may serve an important role in TNBC.

Clinical significance of serum leptin, vascular endothelial growth factor and alpha-fetoprotein expression in hepatocelluar carcinoma

AIM: To explore the expression of serum leptin (Lep), vascular endothelial growth factor (VEGF) and alpha-fetoprotein (AFP) and their clinical significances in hepatocelluar carcinoma (HCC).

METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to detect serum Lep, VEGF and AFP levels in 146 patients with HCC, 31 patients with liver cirrhosis and 30 healthy controls. The correlations Lep, VEGF, and AFP expression with clinical indexes were analyzed.

RESULTS: The serum Lep level was correlated with body mass index (BMI) in HCC patients (r = 0.64, P < 0.01), and significantly lower than that in cirrhotic patients and healthy controls (19 μg/L vs 35, 27 μg/L, P < 0.05). The serum Lep level in HCC patients was significantly decreased with upgrade of TNM stages, metastasis and recurrence (P < 0.05). In comparison with that in cirrhotic patients and healthy controls, the serum VEGF level in HCC patients was significantly increased (398 ng/Lvs 179, 167 ng/L, P < 0.01). There was no correlation between VEGF and AFP expression. The sensitivity and specificity of VEGF were 71.2% and 80.6%, and those of AFP were 73.3% and 83.9%, respectively, in the diagnosis of HCC. However, the sensitivity was increased to 91.8%, while the accuracy reached 90.4% after the combined detection of VEGF and AFP was used. There was a relationship beween the level of serum VEGF and tumor size (<3 cm: 237 ± 96 ng/L, >3 cm: 398 ± 124 ng/L, P < 0.01). As compared with that of TNMⅠ, Ⅱ stage, the serum VEGF of TNM Ⅲ, Ⅳstage was obviously higher (346 ± 131, 401 ± 152 ng/L vs 228 ± 89, 259 ± 102 ng/L, P < 0.01), and it also showed a significant elevation in the patients with metastasis and recurrent HCC (P < 0.01).

CONCLUSION: Nutrition status and prognosis of patients with HCC can be judged by serum Lep level, and the combined detection of serum VEGF and AFP may provide a significant marker for HCC diagnosis and prognosis.

Nuclear ING2 expression is reduced in human cutaneous melanomas

Cutaneous malignant melanoma is a severe and sometimes life-threatening cancer. The molecular mechanism of melanomagenesis is incompletely understood. Deregulation of apoptosis is probably one of the key factors contributing to the progression of melanoma. The inhibitor of growth (ING) family proteins are candidate tumour suppressors which play important roles in apoptosis. Downregulated expression of ING proteins have been reported in several tumour types, including the loss of nuclear expression of p33ING1b in melanoma. As ING2 exhibits 58.9% homology with p33ING1b, we hypothesized that the aberrant expression of ING2 may be involved in melanomagenesis. Here, we used tissue microarray technology and immunohistochemistry to examine ING2 expression in human nevi and melanoma biopsies. Our data showed that nuclear ING2 expression was significantly reduced in radial growth phase (RGP), vertical growth phase (VGP), and metastatic melanomas compared with dysplastic nevi (P < 0.05). Our data also revealed that nuclear ING2 expression was not associated with patient's gender, age or tumour thickness, ulceration, American Joint Committee on Cancer (AJCC) stage, tumour subtype, location and 5-year survival (P > 0.05). Taken together, our results suggest that nuclear ING2 expression is significantly reduced in human melanomas and that reduced ING2 may be an important molecular event in the initiation of melanoma development.

Reduced Apaf-1 expression in human cutaneous melanomas

Malignant melanoma is a life-threatening skin cancer due to its highly metastatic character and resistance to radio- and chemotherapy. It is believed that the ability to evade apoptosis is the key mechanism for the rapid growth of cancer cells. However, the exact mechanism for failure in the apoptotic pathway in melanoma cells is unclear. p53, the most frequently mutated tumour suppressor gene in human cancers, is a key apoptosis inducer. However, p53 mutation is only found in 15–20% of melanoma biopsies. Recently, it was found that Apaf-1, a downstream target of p53, is inactivated in metastatic melanoma. Specifically, loss of heterozygosity (LOH) of the Apaf-1 gene was found in 40% of metastatic melanoma. To determine if loss of Apaf-1 expression is indeed involved in melanoma progression, we employed the tissue microarray technology and examined Apaf-1 expression in 70 human primary malignant melanoma biopsies by immunohistochemistry. Our data showed that Apaf-1 expression is significantly reduced in melanoma cells compared with normal nevi (χ²=6.02, P=0.014). Our results also revealed that loss of Apaf-1 was not associated with the tumour thickness, ulceration or subtype, patient's gender, age and 5-year survival. In addition, our in vitro apoptosis assay revealed that overexpression of Apaf-1 can sensitise melanoma cells to anticancer drug treatment. Taken together, our data indicate that Apaf-1 expression is significantly reduced in human melanoma and that Apaf-1 may serve as a therapeutic target in melanoma.