Invasive characteristics of human prostatic epithelial cells: understanding the metastatic process

Prostate cancer has a predilection to metastasise to the bone marrow stroma (BMS) by an as yet uncharacterised mechanism. We have defined a series of coculture models of invasion, which simulate the blood/BMS boundary and allow the elucidation of the signalling and mechanics of trans-endothelial migration within the complex bone marrow environment. Confocal microscopy shows that prostate epithelial cells bind specifically to bone marrow endothelial-to-endothelial cell junctions and initiate endothelial cell retraction. Trans-endothelial migration proceeds via an epithelial cell pseudopodial process, with complete epithelial migration occurring after 232±43 min. Stromal-derived factor-1 (SDF-1)/CXCR4 signalling induced PC-3 to invade across a basement membrane although the level of invasion was 3.5-fold less than invasion towards BMS (P=0.0007) or bone marrow endothelial cells (P=0.004). Maximal SDF-1 signalling of invasion was completely inhibited by 10 μM of the SDF-1 inhibitor T140. However, 10 μM T140 only reduced invasion towards BMS and bone marrow endothelial cells by 59% (P=0.001) and 29% (P=0.011), respectively. This study highlights the need to examine the potential roles of signalling molecules and/or inhibitors, not just in single-cell models but in coculture models that mimic the complex environment of the bone marrow

Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke

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Connexin 43 mediated gap junctional communication enhances breast tumor cell diapedesis in culture

INTRODUCTION: Metastasis involves the emigration of tumor cells through the vascular endothelium, a process also known as diapedesis. The molecular mechanisms regulating tumor cell diapedesis are poorly understood, but may involve heterocellular gap junctional intercellular communication (GJIC) between tumor cells and endothelial cells. METHOD: To test this hypothesis we expressed connexin 43 (Cx43) in GJIC-deficient mammary epithelial tumor cells (HBL100) and examined their ability to form gap junctions, establish heterocellular GJIC and migrate through monolayers of human microvascular endothelial cells (HMVEC) grown on matrigel-coated coverslips. RESULTS: HBL100 cells expressing Cx43 formed functional heterocellular gap junctions with HMVEC monolayers within 30 minutes. In addition, immunocytochemistry revealed Cx43 localized to contact sites between Cx43 expressing tumor cells and endothelial cells. Quantitative analysis of diapedesis revealed a two-fold increase in diapedesis of Cx43 expressing cells compared to empty vector control cells. The expression of a functionally inactive Cx43 chimeric protein in HBL100 cells failed to increase migration efficiency, suggesting that the observed up-regulation of diapedesis in Cx43 expressing cells required heterocellular GJIC. This finding is further supported by the observation that blocking homocellular and heterocellular GJIC with carbenoxolone in co-cultures also reduced diapedesis of Cx43 expressing HBL100 tumor cells. CONCLUSION: Collectively, our results suggest that heterocellular GJIC between breast tumor cells and endothelial cells may be an important regulatory step during metastasis

Retrovirally transduced antisense sequences stably suppress P210BCR-ABL expression and inhibit the proliferation of BCR/ABL-containing cell lines.

There is now strong evidence that the BCR-ABL gene product of the Philadelphia chromosome (P210) plays a crucial role in the pathogenesis of chronic myeloid leukemia (CML). We have previously shown that introduction of antisense oligonucleotides into K562 cells could transiently block the expression of P210 and specifically inhibit cellular growth in culture. In this report, we describe the use of a retroviral vector to introduce selected antisense and sense sequences, first into murine B10 cells, previously rendered interleukin-3 (IL-3) independent by transfection of BCR-ABL sequences, and second into K562 cells. The antisense transcripts generated under the control of MoMLV promoter specifically killed B10 cells in the absence of IL-3 and inhibited P210 expression almost completely. In K562 cells, the antisense sequences led to a dramatic reduction of P210 expression and increased their doubling time by more than twofold. This effect was not reversed by the addition of exogenous IL-3 to the culture medium. Control HeLa or HL60 cells infected with the same constructs did not show any change in proliferation rate, despite abrogation of the normal BCR gene products. Rather unexpectedly, P210 suppression was not lethal in K562 cells, showing that such a cell line does not rely entirely on the expression of P210 for surviving, but depends on it as far as growth properties are concerned. We conclude that this approach can successfully achieve stable suppression of the oncogenic protein P210 and may be used to study further the mechanisms by which P210 is transforming cells. The effect on fresh CML cells in bone marrow cultures remains to be assessed before we can tell whether this technique may be used for selective suppression of leukemic hematopoiesis in vitro.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

A survey of fully haploidentical hematopoietic stem cell transplantation in adults with high-risk acute leukemia: a risk factor analysis of outcomes for patients in remission at transplantation.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is an alternative treatment to patients with high-risk acute leukemia lacking a human leukocyte antigen-matched donor. We analyzed 173 adults with acute myeloid leukemia (AML) and 93 with acute lymphoblastic leukemia (ALL) who received a haplo-HSCT in Europe. All grafts were T cell-depleted peripheral blood progenitor cells from a direct family or other related donor. At transplantation, there were 25 patients with AML in CR1 (complete remission 1), 61 in more than or equal to CR2, and 87 in nonremission, and 24 with ALL in CR1, 37 in more than or equal to CR2, and 32 in nonremission. Median follow-up was 47 months in AML and 29 months in the ALL groups. Engraftment was observed in 91% of the patients. Leukemia-free survival at 2 years was 48% plus or minus 10%, 21% plus or minus 5%, and 1% for patients with AML undergoing transplantation in CR1, more than or equal to CR2, and nonremission, and 13% plus or minus 7%, 30% plus or minus 8%, and 7% plus or minus 5% in ALL patients, respectively. In conclusion, haplo-HSCT can be an alternative option for the treatment of high-risk acute leukemia patients in remission, lacking a human leukocyte antigen-matched donor

Donor lymphocyte infusions in adult haploidentical transplant: a dose finding study.

Haploidentical transplantation has become a clinical option for patients lacking a compatible donor. However, patients are still referred at advanced stages and are usually heavily pretreated. This results in a high risk of toxicity, relapses and infections. We therefore started a donor lymphocyte infusion (DLI) dose-finding protocol, to try to improve both relapse rate and immunity reconstitution. In all, 12 consecutive patients were investigated. All had a refractory, some progressive, disease. Conditioning consisted of TBI, melphalan, ATG, fludarabine and CSA pretransplant. In four rapidly progressive patients, Ara-C had to be given 1 week preconditioning. The graft was T- and B-cell depleted with a fixed reinfused CD3 dose of 5 x 10(4)/kg. All patients engrafted before day 20. G-CSF was given from day 5 post-transplant and replaced with GM-CSF in the last three patients. Nonrelapse related mortality was 0/12 at 1 year. DLI were started at day 28 (3 x 10(4) CD3/kg) in the two first patients. This resulted in acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD) in both, but they did not relapse. The next dose was 1 x 10(4)/kg monthly for 3 months. This was well tolerated with only one grade I GVHD. Given the high relapse rate, we escalated doses (1, 3 and 10 x 10(4)/kg). This produced GVHD in all. We next moved, to GM-CSF and 1 x 10(4) CD3/kg monthly. Overall, 6/12 patients relapsed and received therapeutic DLI, starting at 1 x 10(5) CD3/kg with escalation every 2 weeks. We conclude that prophylactic DLI are feasible in adult haploidentical transplantation, without GVHD at a monthly dose of 1 x 10(4) CD3/kg. They result in faster CD4 recovery and a low rate of infections. The impact of GM-CSF remains to be further investigated. This scheme seems ideal for patients transplanted early in the course of their disease. In very bad prognosis patients, it remains insufficient to rapidly induce a GVL effect. Escalated doses are feasible but the price is aGVHD. Therapeutic DLI can be given at higher doses, depending on the time post-transplant. Haploidentical transplantation with low-dose DLI is a safe procedure that should be considered in all patients needing a transplant, but lacking a matched donor, early in the course of the disease.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe