All-trans retinoic acid arrests cell cycle in leukemic bone marrow stromal cells by increasing intercellular communication through connexin 43-mediated gap junction.

BACKGROUND: Gap junctional intercellular communication (GJIC) is typically decreased in malignant tumors. Gap junction is not presented between hematopoietic cells but occurred in bone marrow stromal cells (BMSCs). Connexin 43 (Cx43) is the major gap junction (GJ) protein; our previous study revealed that Cx43 expression and GJIC were decreased in acute leukemic BMSCs. All-trans retinoic acid (ATRA) increases GJIC in a variety of cancer cells and has been used to treat acute promyelocytic leukemia, but the effects of ATRA on leukemic BMSCs is unknown. In this study, we evaluated the potential effects of ATRA on cell cycle, proliferation, and apoptosis of leukemic BMSCs. Effects of ATRA on Cx43 expression and GJIC were also examined. METHODS: Human BMSCs obtained from 25 patients with primary acute leukemia, and 10 normal healthy donors were cultured. Effects of ATRA on cell cycle, cell proliferation, and apoptosis were examined with or without co-treatment with amphotericin-B. Cx43 expression was examined at both the mRNA and protein expression levels. GJIC was examined by using a dye transfer assay and measuring the rate of fluorescence recovery after photobleaching (FRAP). RESULTS: ATRA arrested the cell cycle progression, inhibited cell growth, and increased apoptosis in leukemic BMSCs. Both Cx43 expression and GJIC function were increased by ATRA treatment. Most of the observed effects mediated by ATRA were abolished by amphotericin-B pretreatment. CONCLUSIONS: ATRA arrests cell cycle progression in leukemic BMSCs, likely due to upregulating Cx43 expression and enhancing GJIC function.

[Impacts of human disturbance on the species composition of higher plants in the wetlands around Dianchi Lake, Yunnan Province of Southwest China].

Introducing higher plants to build semi-natural wetland ecosystem is one of the key approaches to restore the wetlands and lakes that suffered from serious pollution and destruction. Based on the investigation data from 128 quadrats at 26 sampling sites in the wetlands around Dianchi Lake in December 2011-October 2012, and in combining with the references published in the 1960s, this paper discussed the impacts of human activities on the species composition of higher plants in the wetlands around the Lake. In 2012, there were 299 species of 88 families in the wetlands, of which, 181 species were native species, and 118 species were alien ones (including 32 invasive species). Of the 42 species of hydrophytes in the total species, 13 species were alien ones (including 2 invasive species). In comparing with the species data recorded in the 1960s, 232 plants were newly recorded and 43 species disappeared in 2012. Aquatic plants changed obviously. The decreased species were 2 submerged plants, 2 floating plants, and 5 floating leaved plants, and the increased species were 8 emergent plants. Fourteen community types were identified by cluster analysis, of which, the main communities were those dominated by alien species including Pistia stratiotes and Alternanthera philoxeroides. As compared with the data in the 1960s, the plant communities dominated by native species such as Ottelia acuminate and Vallisneria natans were not found presently. Therefore, in the practice of introducing higher plants to restore the degraded wetlands and lakes, it would be necessary to scientifically and appropriately select and blend plant species to avoid the wetland degradation by human activities.

[Intracerebral infiltration by monoclonal plasmacytoid cells in Waldenstrom's macroglobulinemia: a case report and review of the literature].

OBJECTIVE: To sum up the clinical experience of the diagnosis and treatment of intracerebral infiltration by monoclonal plasmacytoid cells in Waldenstrom's macroglobulinemia(Bing-Neel syndrome). METHODS: The clinical data of the diagnosis and treatment of a case of Bing-Neel syndrome was analyzed. RESULTS: A 56-year-old male was diagnosed as Waldenstrom's macroglobulinemia one year ago, and presented with persistent headache during the treatment period. Magnetic resonance imaging showed a high intensity area on T2-weighed images in the right frontal lobe which was well enhanced by gadolinium-diethylenetriaminepenta-acetic acid. Infiltration of neoplastic cells was confirmed by biopsy. Immunohistochemical examination showed that mature plasmacytoid cells in the cerebral parenchyma were immunoglobulin M positive. CONCLUSION: Infiltration in CNS (Bing-Neel syndrome) is uncommon in Waldenstrom's macroglobulinemia. As there is no effective therapy for this Bing-Neel syndrome, combination of radiation and chemotherapy should be considered for this situation.

[Effect of zoledronic acid on the growth and CD138 expression of myeloma cell line KM3].

OBJECTIVE: To study the inhibitory effect of zoledronic acid (ZA) on the growth and CD138 expression of myeloma cell line KM3. METHODS: KM3 cells were treated with different concentrations of ZA The growth of KM3 cells was measured by trypan blue dye exclusion, and the changes of apoptosis rate, cell cycle and expression of CD138 induced by ZA by flow cytometry. RESULTS: Within the concentration of 10(-5)-10(-3) mol/L, ZA obviously inhibited the growth of KM3 cells in a dose dependent manner. IBN at 10(-5)-10(-4) moL/L increased Annexin V positive rate, blocked cells at the S/G2 boundary, reduced the expression of CD138 and its fluorescence intensity. CONCLUSION: ZA can inhibit the growth of KM3 cells in a dose-dependent manner and inhibited CD138 expression. The mechanism is probably related to induction cell cycle accumulation in S phase and apoptosis.