Prognostic significance of beta-catenin and topoisomerase IIalpha in de novo acute myeloid leukemia.

The Wnt/beta-catenin signaling is important for controlling self-renewal of hematopoietic stem cells and its constitutive activation has recently been documented in a significant proportion of acute myeloid leukemia (AML) cases. Topoisomerase IIalpha (Topo IIalpha) is a marker of cell proliferation and a crucial target for anthracycline cytotoxicity, the mainstay of management employed in AML. We retrospectively investigated the prognostic roles of beta-catenin and topo IIalpha in a cohort of 59 patients with newly diagnosed AML by immunohistochemistry. Aberrant beta-catenin expression was demonstrated in 13 patients (22%), and it was more likely to occur in those with unfavorable karyotypes. Advanced age and poor performance status adversely influenced the achievement of complete remission, while neither aberrant beta-catenin expression nor enhanced topo IIalpha activity did. On multivariate survival analysis, four factors independently predicted a shortened overall survival: aberrant beta-catenin expression, high topo IIalpha activity, poor-risk cytogenetics, and presence of at least one comorbidity factor. Our results suggest that both beta-catenin and topo IIalpha independently predicted an adverse prognosis and might serve as new markers for risk stratification in AML patients.

Altered mRNA expressions of sialyltransferases in ovarian cancers.

OBJECTIVE: Aberrant glycosylation occurs in essentially all types of experimental and human cancers, and many glycosyl epitopes constitute tumor-associated antigens (for example, CA125). Many recent studies have indicated that some, if not all, aberrant glycosylation is a result of altered sialyltransferase (ST) expression; however, there is little known of the role of the altered mRNA expression of ST in ovarian cancers. METHODS: Alterations in ST mRNA expression in postmenopausal ovarian tissues, including those of normal controls (n=24) and malignant serous ovarian cancers (n=24), were examined by means of real-time quantitative reverse transcription-polymerase chain reaction (RTQ-PCR). Maackia Amurensis Agglutinin type 2 (MAA) specific foralpha2,3-linked NeuNAc was used for immunohistochemical staining. RESULTS: Among these five STs, the mRNA expressions of three STs, including ST3Gal III, ST3Gal IV, and ST3Gal VI, were significantly decreased in patients with ovarian cancers, compared to the normal controls (P<0.001). By contrast, the mRNA expressions of ST3Gal I and ST6Gal I were increased in ovarian cancer tissues, compared to those of the normal controls (P<0.001). The ovarian epithelial carcinoma part showed strong positivity for MAA, whereas MAA staining in the stromal part was negative. Both the epithelial part and the stromal part of postmenopausal ovarian tissue showed negativity for MAA staining. However, clinico-pathological parameters, including stage, differentiation, amount of ascites, and serum levels of CA125, did not show any correlation to mRNA expression of any given-type ST. CONCLUSIONS: Our results suggest that altered mRNA expressions of alpha2,3-sialyltransferase ST3Gal I, ST3Gal III, ST3Gal IV, ST3Gal VI, andalpha2,6-sialyltransferase ST6Gal I are of importance in malignant ovarian cancers. An increased expression of ST3Gal I may contribute directly to increased alpha2,3-linked sialylation in ovarian serous carcinoma.

Soyasaponin-I-modified invasive behavior of cancer by changing cell surface sialic acids.

OBJECTIVE: Sialylation involving tumor formation and invasive behavior goes along with altered sialyltransferase (ST) activity. A potent ST inhibitor, soyasaponin I (SsaI), was discovered to selectively inhibit the cellular alpha2,3-sialyltranserase activity. In this study, we further test the effects of SsaI on modifying the metastatic and invasive behaviors of cancer cell lines. METHODS: Nonmetastatic breast cancer cell line, MCF-7, and highly metastastic breast cancer cell line, MDA-MB-231, were used to investigate the effects of SsaI on tumor cells. RESULTS: SsaI did not affect cell growth cycle and also failed to inhibit cell growth in this study (the concentration of SsaI < or=100 muM). SsaI was as predicted to successfully inhibit cellular alpha2,3-ST activity and depressed the dose-dependent tumor cell surface alpha2,3-sialic acid expression. In addition, different concentrations of SsaI did stimulate MCF-7 cell adhesion to collagen type I linearly and significantly enhanced cell adhesion to the Matrigel-matrix. Furthermore, SsaI significantly decreased MDA-MB-231 cell migration. Reverse transcriptase polymerase chain reaction for evaluating mRNA expression of ST3Gal I, III and IV showed that SsaI also down-regulated the expression of ST3Gal IV but did not affect the other two. CONCLUSIONS: The results showed that SsaI was implicated in the invasive behavior of tumor cells, suggesting that altered alpha2,3-sialylation pathway played a crucial role in the adhesion and tumor metastases. SsaI is a good candidate for studying the biological roles of ST, and might provide a new preventive strategy in tumor metastasis.