Patrik Georgii-Hemming

Expression of the bcl-2 family of pro- and anti-apoptotic genes in multiple myeloma and normal plasma cells : regulation during interleukin-6(IL-6)-induced growth and survival.

Abstract: Aberrant expression of genes regulating apoptosis/survival seems to be essential in the stepwise development of human multiple myeloma (MM). In this paper we have compared the expression of bcl‐2 family pro‐ and anti‐apoptotic genes in MM cell lines, primary MM cells and normal plasma cells. The Bcl‐2, Mcl‐1, Bcl‐xL/S, Bcl‐w, Bax, Bak, and Bad were shown to be expressed in both malignant and non‐neoplastic, normal plasma cells. Quantitative analysis revealed that the malignant phenotype seemed to correlate with an elevated expression of Mcl‐1, a decreased expression of Bax and, to a lesser extent, an increased Bcl‐2/Bax expression ratio. The possible influence of interleukin‐6 (IL‐6) in regulating the expression of the bcl‐2‐related genes was also examined. Using the IL‐6‐dependent MM cell lines U‐1958 and U‐266–1970 it was clearly shown that IL‐6 deprivation induced cell cycle arrest in both cell lines, whereas apoptosis was only detected in the U‐1958 cells. Furthermore, the anti‐apoptotic proteins Bcl‐2, Mcl‐1 and Bcl‐xL were down‐regulated, while the expression of the pro‐apoptotic Bax protein was increased. To conclude, we suggest that the expression pattern of the Bcl‐2 family of proteins separates the malignant phenotype of MM from normal plasma cells, and that the protecting effect of IL‐6 may be conducted via an altered balance between these proteins.

Transcriptional profiling of human glioblastoma vessels indicates a key role of VEGF-A and TGFβ2 in vascular abnormalization.

Glioblastoma are aggressive astrocytic brain tumours characterized by microvascular proliferation and an abnormal vasculature, giving rise to brain oedema and increased patient morbidity. Here, we have characterized the transcriptome of tumour‐associated blood vessels and describe a gene signature clearly associated with pleomorphic, pathologically altered vessels in human glioblastoma (grade IV glioma). We identified 95 genes differentially expressed in glioblastoma vessels, while no significant differences in gene expression were detected between vessels in non‐malignant brain and grade II glioma. Differential vascular expression of ANGPT2, CD93, ESM1, ELTD1, FILIP1L and TENC1 in human glioblastoma was validated by immunohistochemistry, using a tissue microarray. Through qPCR analysis of gene induction in primary endothelial cells, we provide evidence that increased VEGF‐A and TGFβ2 signalling in the tumour microenvironment is sufficient to invoke many of the changes in gene expression noted in glioblastoma vessels. Notably, we found an enrichment of Smad target genes within the distinct gene signature of glioblastoma vessels and a significant increase of Smad signalling complexes in the vasculature of human glioblastoma in situ. This indicates a key role of TGFβ signalling in regulating vascular phenotype and suggests that, in addition to VEGF‐A, TGFβ2 may represent a new target for vascular normalization therapy. Copyright

Tolerance induction ameliorates allograft vasculopathy in rat aortic transplants. Influence of Fas-mediated apoptosis.

Based on successful induction of donor-specific unresponsiveness by alloantigenic stimulation in several animal models of acute rejection, we hypothesized that similar immune manipulations would also inhibit the evolution of chronic rejection and transplant vasculopathy. To induce immune tolerance, DA rats received a PVG heart allograft and were immunosuppressed with cyclosporine for 30 d. At day 100 the animals were challenged with a PVG aortic allograft after either 1 or 18 h of cold ischemia. 8 wk after the aortic transplantation, the grafts were investigated for morphological changes, infiltrating cells, apoptosis, and Fas-Fas ligand expression. Control allografts showed advanced transplant arteriosclerosis, whereas tolerance-induced aortic allografts displayed reduced neointimal formation, less medial atrophy, fewer apoptotic cells, and fewer Fas- and FasL-expressing cells. Prolonged ischemic storage time did not profoundly alter the morphological changes of the allografts. Fas expression was found in T cells, macrophages, vascular smooth muscle cells, and endothelial cells, whereas FasL was expressed mainly by T cells and macrophages. FasL mRNA expression was evident throughout the entire allograft wall. In conclusion, induction of allospecific tolerance can effectively prevent transplant arteriosclerosis. Cold ischemia damage does not abrogate the beneficial effect of tolerance, but creates a separate identity of mainly endothelial lesions. Furthermore, Fas-mediated apoptosis appears to be involved in the pathological lesions seen in chronic rejection.

Role of microRNAs and microRNA machinery in the pathogenesis of diffuse large B-cell lymphoma

Deregulation of microRNA (miRNA) expression has been documented in diffuse large B-cell lymphoma (DLBCL). However, the impact of miRNAs and their machinery in DLBCL is not fully determined. Here, we assessed the role of miRNA expression and their processing genes in DLBCL development. Using microarray and RT-qPCR approaches, we quantified global miRNAs and core components of miRNA-processing genes expression in 75 DLBCLs (56 de novo and 19 transformed) and 10 lymph nodes (LN). Differential miRNA signatures were identified between DLBCLs and LNs, or between the de novo and transformed DLBCLs. We also identified subsets of miRNAs associated with germinal center B-cell phenotype, BCL6 and IRF4 expression, and clinical staging. In addition, we showed a significant over-expression of TARBP2 in de novo DLBCLs as compared with LNs, and decreased expression of DROSHA, DICER, TARBP2 and PACT in transformed as compared with de novo cases. Interestingly, cases with high TARBP2 and DROSHA expression had a poorer chemotherapy response. We further showed that TARBP2 can regulate miRNA-processing efficiency in DLBCLs, and its expression inhibition decreases cell growth and increases apoptosis in DLBCL cell lines. Our findings provide new insights for the understanding of miRNAs and its machinery in DLBCL.

The control of proliferation, survival and apoptosis in human multiple myeloma cells in vitro.

The biology of human multiple myeloma (MM) was poorly understood until recently. Only when IL-6 had been identified as an important growth factor for MM cells has it been possible to establish cell lines and to maintain fresh MM biopsy cells in vitro for weeks-months (Kawano et al 1988, Klein et al 1990, Nilsson et al 1990). This has allowed controlled in vitro studies of various aspects of the genotype and phenotype of MM cells during the 1990s. Some features are characteristic for MM cells. They include a restriction of the growth of MM cells almost exclusively to the bone marrow, chromosomal heterogeneity within and between individual MM clones, genetic instability, the presence at a high frequency of a translocation to the immunoglobulin (Ig) heavy chain or Ig light chain locus, a high and deregulated expression of c-Myc, a high expression of Bcl-2 and often a dependence of IL-6 and/or IGF-I as growth and survival factors. A common characteristic of MM cells both in vitro and in vivo is also that they proliferate slowly. At the population level the doubling time is often several days as a result of a long generation time (usually exceeding 36 hrs) and a high apoptotic rate. The first MM cell line established in our laboratory was in 1970 (Nilsson et al 1970). During the following decades additional MM lines were established (Nilsson, 1992) and a selected panel of lines, consisting also of MM cell lines established elsewhere, have been instrumental in studies on the control of growth and apoptosis during the last few years.

The gynecological surveillance of women with Lynch syndrome in Sweden

OBJECTIVE Women with Lynch syndrome (LS) have up to a 60% lifetime risk of endometrial cancer (EC) and up to a 24% risk of ovarian cancer (OC). Gynecological surveillance is recommended, but the benefit and how it should be performed remain unclear. The purpose of this study was to assess diagnostic modalities for gynecological screening of LS patients in Sweden and clinical outcome. METHODS A retrospective nationwide study of 170 women with molecularly confirmed LS. Data including gynecological LS screening history, biopsy results (if any), genetic records, number of screening visits, results from screening including transvaginal ultrasound (TVUS), endometrial biopsy (EB), blood test for tumor marker cancer antigen (CA) 125, prophylactic surgery including age at procedure, and setting from which screening data were obtained from medical records. RESULTS A total of 117 women were eligible for gynecological screening and of these, 86 patients attended screening visits. Of these, 41 underwent prophylactic hysterectomy and/or bilateral salpingo-oophorectomy. Two patients (4.9%) were diagnosed with EC and two (4.9%) with precancerous lesions in conjunction with prophylactic surgery. Total incidence of gynecological cancer in the surveillance group (45 women) was 20% EC, 4% OC. Five patients had endometrial cancer or complex hyperplasia with atypia (n=2) detected by endometrial biopsy. Four additional cases were detected due to interval bleeding. Both cases of ovarian cancer were detected by transvaginal ultrasound in patients with ovarian cysts under surveillance. The youngest woman with endometrial cancer was diagnosed at 35 years of age, before she was aware of her diagnosis of Lynch syndrome. CONCLUSIONS Gynecological surveillance of women with Lynch syndrome may lead to earlier detection of precancerous lesions, which might have some impact on the morbidity from endometrial cancer although further studies are needed to prove this. Prophylactic hysterectomy with or without bilateral salpingo-oophorectomy reduces the cancer incidence. A practical approach to surveillance in Lynch syndrome women would be to offer annual surveillance beginning at age 30 years including probably both TVUS and EB in order to increase diagnostic yield with prospective data registry for follow-up studies. Prophylactic surgery could be performed at a suitable age after childbearing to obtain a balance between reducing the risk of cancer and minimizing long-term complications from premature menopause.