A novel small molecule aurora kinase inhibitor attenuates breast tumor-initiating cells and overcomes drug resistance.

Chemoresistance is a major cause of cancer treatment failure. Tumor-initiating cells (TIC) have attracted a considerable amount of attention due to their role in chemoresistance and tumor recurrence. Here, we evaluated the small molecule Aurora kinase inhibitor AKI603 as a novel agent against TICs in breast cancer. AKI603 significantly inhibited Aurora-A (AurA) kinase and induced cell-cycle arrest. In addition, the intragastric administration of AKI603 reduced xenograft tumor growth. Interestingly, we found that breast cancer cells that were resistant to epirubicin expressed a high level of activated AurA and also have a high CD24(Low)/CD44(High) TIC population. The inhibition of AurA kinase by AKI603 abolished the epirubicin-induced enrichment of TICs. Moreover, AKI603 suppressed the capacity of cells to form mammosphere and also suppressed the expression of self-renewal genes (ß-catenin, c-Myc, Sox2, and Oct4). Thus, our work suggests the potential clinical use of the small molecule Aurora kinase inhibitor AKI603 to overcome drug resistance induced by conventional chemotherapeutics in breast cancer.

GRP78 upregulation-induced increase in cisplatin sensitivity of SPCA1 lung cancer cells.

BACKGROUND: Glucose regulated protein 78 (GRP78), an endoplasmic reticulum (ER) chaperone, plays a critical role in chemotherapy resistance in a variety of cancers. In this study, we investigated the up-regulation of GRP78 induced by A23187 and its association with the chemotherapeutical sensibility to cisplatin in human lung cancer cell line SPCA1. METHODS: SPCA1 cells were pretreated with A23187 at different concentrations. The expression of GRP78 at the mRNA level was analyzed by RT-PCR; the expression of GRP78 at the protein level was determined by Western blotting and immunofluorescence assay. Cell survival was determined by MTT assay. Cell apoptosis was analyzed by flow cytometry. RESULTS: The expression of GRP78 at both the mRNA and protein levels was obviously induced by A23187 in SPCA1 cells, with an elevation of GRP78 by 2.1-fold at the mRNA level and by 3.8-fold at the protein level compared to the control. There was a dose-dependent response. Survival curve analysis demonstrated that A23187 induction caused a significant reduction of survival for the cells subjected to cisplatin treatment (P < 0.05). After treatment by cisplatin, the percentage of apoptotic cells in the A23187 pretreated group increased about three fold compared with the control group ((27.53 ± 4.32)% vs. (9.25 ± 3.64)%, P < 0.05). CONCLUSIONS: A23187 treatment was fairly effective for the induction of GRP78 in SPCA1 cells at both the mRNA and protein levels. To a certain extent, GRP78 up-regulation by A23187 was associated with the enhancement of drug sensitivity to cisplatin in human lung cancer cell line SPCA1.

[Clinical significance of abnormal expression of Aurora-A in human esophageal squamous cell carcinoma with or without lymph node metastasis].

OBJECTIVE: China has the highest incidence and mortality of esophageal carcinoma in the world, and the esophageal squamous cell carcinoma (ESCC) is the major type. In this study, the authors investigated the expression of Aurora-A in stage T3 esophageal squamous cell carcinomas (ESCC) with positive and negative lymph node metastasis, and analyzed its relationship with prognosis of ESCC patients. METHODS: ESCC tissue arrays including 212 specimens had been constructed. The expression of Aurora-A in both ESCC tissues and adjacent normal tissues was determined by immunohistochemical staining. The correlation between Aurora-A protein levels and lymph node status in ESCC and survival rate were statistically analyzed. RESULTS: The positive expression of Aurora-A was 74.07% (140/189) in tumor tissues and 18.52% (35/189) in adjacent normal tissues, showing a significant difference between them (χ(2) = 105.162, P < 0.05). In tumors with positive lymph nodes, strong positive expression of Aurora-A was found in 42.99% (46/107), while only 7.37% (7/95) in tumors with negative lymph nodes, with a statistically significant difference (χ(2) = 36.132, P < 0.05). The cumulative survival rate of the patients with strong Aurora-A-positive tumors was significantly lower than that in patients with Aurora-A-negative tumors (P = 0.0042, P < 0.05). CONCLUSION: The positive expression of Aurora-A in ESCC tissues is much higher than that in adjacent normal tissues. The expression of Aurora-A is higher in lymph node-positive tumors than in the lymph node-negative ones. There is a significantly longer cumulative survival rate in patients with negative Aurora-A expression than that in patients with strong positive Aurora-A expression.

[Expression of aurora-A kinase in human lung cancer cell lines PG, A549, and NCI-H460].

BACKGROUND & OBJECTIVE: Recent researches found that Aurora-A overexpresses in various malignancies. This study was to detect the expression of Aurora-A in lung cancer cell lines PG (highly-metastatic giant cell lung cancer), A549 (lung adenocarcinoma), and NCI-H460 (large cell lung cancer) and explore its correlation to DNA content, provide a theoretical basis for screening tumor marker and molecular therapeutic target of lung cancer. METHODS: mRNA and protein levels of Aurora-A in PG, A549, and NCI-H460 cells were detected by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot. Flow cytometry was used to analyze DNA contents in cell cycles of PG, A549, and NCI-H460 cells. RESULTS: mRNA level of Aurora-A was 1.14 in PG cells, 1.16 in A549 cells, and 0.84 in NCI-H460 cells, respectively; protein level of Aurora-A was 8.96 in PG cells, 21.13 in A549 cells, and 6.43 in NCI-H460 cells, respectively. The proportion of cells with tetraploid DNA was 19.88% in PG cells, 14.97% in A549 cells, and 10.6% in NCI-H460 cells, respectively (P<0.01); the proportion of cells with polyploid DNA was 2.66% in PG cells, 3.59% in A549 cells, and 2.30% in NCI-H460 cells, respectively. CONCLUSION: Aurora-A is overexpressed in the 3 lung cancer cell lines, but the mRNA levels are different.

Highly sensitive determination of the methylated p16 gene in cancer patients by microchip electrophoresis.

The p16 tumor suppressor gene is inactivated by promoter region hypermethylation in many types of tumor. Recent studies showed that aberrant methylation of the p16 gene is an early event in many tumors, especially in lung cancer, and may constitute a new biomarker for early detection and monitoring of prevention trials. We detected tumor-associated aberrant hypermethylation of the p16 gene in plasma and tissue DNA from 153 specimens using a modified semi-nested methylation-specific PCR (MSP) combining plastic microchip electrophoresis or slab gel electrophoresis, respectively. Specimens were from 79 lung cancer patients, 15 abdominal tumor patients, 30 positive controls and 30 negative controls. The results showed that the positive rate obtained by microchip electrophoresis was more than 26.6% higher and the same specificity was kept when compared with slab gel electrophoresis. The microchip electrophoresis can rapidly and accurately analyze the PCR products of methylated DNA and obviously improve the positive rate of diagnosis of cancer patients when compared with gel electrophoresis. This method with the high assay sensitivity might be used for detection of methylation of p16 gene and even to facilitate early diagnosis of cancer patients.

[Abnormalities of molecular biology in premalignant lung lesions].

In recent twenty years, the incidence of lung cancer has increased quickly in our country. Till now, the morbidity and mortality of lung cancer have occupied the top of the cancers. Early diagnosis is the most important key to increase the five-year survival rate. This review is attempted to summarize the early hereditary events during the development of lung cancer, mainly including the mutation of p53 gene, the abnormal methylation of the promoter area of p16 gene, the loss of heterozygosity of 3p, 8p, 9p, 5q, etc. The purpose is to seek the biological markers during the development of lung cancer to provide theoretical basis for treatment of lung cancer.