miR-181b as a therapeutic agent for chronic lymphocytic leukemia in the Eμ-TCL1 mouse model

The involvement of microRNAs (miRNAs) in chronic lymphocytic leukemia (CLL) pathogenesis suggests the possibility of anti-CLL therapeutic approaches based on miRNAs. Here, we used the Eμ-TCL1 transgenic mouse model, which reproduces leukemia with a similar course and distinct immunophenotype as human B-CLL, to test miR-181b as a therapeutic agent.In vitro enforced expression of miR-181b mimics induced significant apoptotic effects in human B-cell lines (RAJI, EHEB), as well as in mouse Eμ-TCL1 leukemic splenocytes. Molecular analyses revealed that miR-181b not only affected the expression of TCL1, Bcl2 and Mcl1 anti-apoptotic proteins, but also reduced the levels of Akt and phospho-Erk1/2. Notably, a siRNA anti-TCL1 could similarly down-modulate TCL1, but exhibited a reduced or absent activity in other relevant proteins, as well as a reduced effect on cell apoptosis and viability. In vivo studies demonstrated the capability of miR-181b to reduce leukemic cell expansion and to increase survival of treated mice.These data indicate that miR-181b exerts a broad range of actions, affecting proliferative, survival and apoptotic pathways, both in mice and human cells, and can potentially be used to reduce expansion of B-CLL leukemic cells.     

t(4;11)(q21;p15) translocation involving NUP98 and RAP1GDS1 genes: characterization of a new subset of T acute lymphoblastic leukaemia

Two cases of T acute lymphoblastic leukaemia (T-ALL) with an identical t(4;11)(q21;p15) translocation were identified within a prospective study on the biological and clinical features of adult ALL patients enrolled into the therapeutic protocol ALL0496 of the GIMEMA Italian Group. In both cases, the molecular characterization showed an involvement of the NUP98 gene on 11p15 which rearranges with the RAP1GDS1 gene on 4q21. The morphological and immunological features of the leukaemic cells, as well as the clinical behaviour and response to induction therapy, were the same in both patients. Based on the available data, the t(4;11)(q21;p15) translocation involving the NUP98-RAP1GDS1 fusion gene emerges as a new highly specific genetic abnormality that characterizes a subset of T-ALL.     

Isolation and characterization of CD146+ multipotent mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) represent a bone marrow (BM) population, classically defined by five functional properties: extensive proliferation, ability to differentiate into osteoblasts, chondrocytes, adipocytes, and stromal cells-supporting hematopoiesis. However, research progress in this area has been hampered by lack of suitable markers and standardized procedures for MSC isolation. We have isolated a CD146(+) multipotent MSC population from 20 human BM donors displaying the phenotype of self-renewing osteoprogenitors; an extensive 12-week proliferation; and the ability to differentiate in osteoblasts, chondrocytes, adipocytes, and stromal cells supporting hematopoiesis. Furthermore, the CD146(+) MSCs secrete a complex combination of growth factors (GFs) controlling hematopoietic stem cells (HSCs) function, while providing a >2-log increase in the long-term culture (LTC) colony output in 8-week LTC over conventional assays. The hematopoietic stromal function exhibited by the MSCs was further characterized by manipulating LTCs with the chemical inhibitors Imatinib or SU-5416, targeting two GF receptors (GFRs), KIT or VEGFR2/1, respectively. Both treatments similarly impaired LTC colony output, indicating key roles for these two GF/GFR interactions to support LTC-initiating cell activity. CD146(+) MSCs may thus represent a tool to explore the MSC-HSC cross-talk in an in vitro surrogate model for HSC "niches," and for regenerative therapy studies. In addition, the MSC microRNA (miRNA) expression profile was analyzed by microarrays in both basic conditions and chondrogenic differentiation. Our analysis revealed that several miRNAs are modulated during chondrogenesis, and many of their putative targets are genes involved in chondrogenic differentiation.     

Alterations of the tumor suppressor gene ARLTS1 in ovarian cancer

ARLTS1 is a tumor suppressor gene initially described as a low-penetrance cancer gene: a truncated Trp149Stop (MUT) polymorphism is associated with general familial cancer aggregation and, particularly, high-risk familial breast cancer. DNA hypermethylation has been identified as a mechanism of ARLTS1 expression down-regulation in lung carcinomas and B-cell chronic lymphocytic leukemia. We found that, in the majority of ovarian carcinomas (61.5%) and in a significant proportion of ovarian and breast cancer cell lines (45%), ARLTS1 is strongly down-regulated due to DNA methylation in its promoter region. After ARLTS1 restoration by adenoviral transduction, only the negative TOV-112 and the homozygously mutated (MUT) MCF7 cells, but not the OV-90 cells expressing a normal ARLTS1 product, underwent apoptosis and inhibition of cell growth. Furthermore, ARLTS1 reexpression significantly reduced the tumorigenic potential of TOV-112 in nude mice. On the contrary, the ARLTS1-MUT induced significantly lower levels of apoptosis in infected cells and reduced in vivo tumorigenesis only partially, supporting the hypothesis that Trp149Stop polymorphism is retained in the general population and predisposes to cancer because of a reduction, but not full loss, of normal ARLTS1 function.     

Medial plantar artery island flap for heel reconstruction

Coverage of soft tissue defects of the heel has been a challenge to reconstructive surgeons in the past. The medial plantar artery flap has facilitated heel coverage since its development in the 1980s. This was a prospective study in 2 centers assessing the complications and durability of this flap primarily in patients with sensory impairment. All patients but 1 had chronic plantar ulceration due to sensory loss, and 5 patients also had developed squamous cell carcinoma. Fifty-one flaps were carried out in 48 patients. One flap underwent necrosis, and delayed healing was seen in 4 cases. Total flap survival was 98%. Minor revision of the flap or its pedicle was required in 3 cases. With a mean follow-up of 14 months, there were recurrences of ulceration in 7 feet (14%). The relevant literature is reviewed. The medial plantar artery flap is a reliable flap for heel coverage in both our centers and others. It is durable and long lasting even in insensate.     

In vitro studies on the metabolism of dibenzo[c,f]-[1,2]diazepine.

Dibenzo [c,f]-[1,2] diazepine is a new compound with a tricyclic structure and a double bond between two nitrogen atoms in positions 1 and 2 of the molecule. Its in vitro metabolism has been studied, incubating the compound with rat liver microsomes. Two metabolites have been identified: dibenzo [c,f] - [1,2]diazepine-1-N-oxide and a monohydroxyderivative in the aromatic ring.