Helen Fernandes

Mesenchymal Stem Cells in Early Entry of Breast Cancer into Bone Marrow

Background An understanding of BC cell (BCC) entry into bone marrow (BM) at low tumor burden is limited when compared to highly metastatic events during heavy tumor burden. BCCs can achieve quiescence, without interfering with hematopoiesis. This occurs partly through the generation of gap junctions with BM stroma, located close to the endosteum. These events are partly mediated by the evolutionary conserved gene, Tac1. Methodogy/Principal Findings This study focuses on the role of mesenchymal stem cells (MSCs), Tac1, SDF-1 and CXCR4 in BCC entry into BM. The model is established in studies with low numbers of tumor cells, and focuses on cancer cells with low metastatic and invasion potential. This allowed us to recapitulate early event, and to study cancer cells with low invasive potential, even when they are part of larger numbers of highly metastatic cells. A novel migration assay showed a facilitating role of MSCs in BCC migration across BM endothelial cells. siRNA and ectopic expression studies showed a central role for Tac1 and secondary roles for SDF-1α and CXCR4. We also observed differences in the mechanisms between low invasive and highly metastatic cells. The in vitro studies were verified in xenogeneic mouse models that showed a preference for low invasive BCCs to BM, but comparable movement to lung and BM by highly metastatic BCCs. The expressions of Tac1 and production of SDF-1α were verified in primary BCCs from paired samples of BM aspirates and peripheral blood. Conclusions/Significance MSC facilitate BCC entry into BM, partly through Tac1-mediated regulation of SDF-1α and CXCR4. We propose a particular population of BCC with preference for BM could be isolated for characterization. This population might be the subset that enter BM at an early time period, and could be responsible for cancer resurgence and resistance to current therapies.

Correcting miR-15a/16 genetic defect in New Zealand Black mouse model of CLL enhances drug sensitivity

Alterations in the human 13q14 genomic region containing microRNAs mir-15a and mir-16-1 are present in most human chronic lymphocytic leukemia (CLL). We have previously found the development of CLL in the New Zealand Black murine model to be associated with a point mutation in the primary mir-15a/16-1 region, which correlated with a decrease in mature miR-16 and miR-15a levels. In this study, addition of exogenous miR-15a and miR-16 led to an accumulation of cells in G1 in non–New Zealand Black B cell and New Zealand Black–derived malignant B-1 cell lines. However, the New Zealand Black line had significantly greater G1 accumulation, suggesting a restoration of cell cycle control upon exogenous miR-15a/16 addition. Our experiments showed a reduction in protein levels of cyclin D1, a miR-15a/16 target and cell cycle regulator of G1/S transition, in the New Zealand Black cell line following miR-15a/16 addition. These microRNAs were shown to directly target the cyclin D1 3′ untranslated region using a green fluorescent protein lentiviral expression system. miR-16 was also shown to augment apoptosis induction by nutlin, a mouse double minute 2 (MDM2) antagonist, and genistein, a tyrosine kinase inhibitor, when added to a B-1 cell line derived from multiple in vivo passages of malignant B-1 cells from New Zealand Black mice with CLL. miR-16 synergized with nutlin and genistein to induce apoptosis. Our data support a role for the mir-15a/16-1 cluster in cell cycle regulation and suggest that these mature microRNAs in both the New Zealand Black model and human CLL may be targets for therapeutic efficacy in this disease. [Mol Cancer Ther 2009;8(9):2684–92]

Investigation of promoter polymorphisms in the tumor necrosis factor-α and interleukin-10 genes in liver transplant patients

Background. Cytokines such as tumor necrosis factor (TNF)-&agr; and interleukin (IL)-10 play significant roles in the inflammatory and immune responses that mediate allograft rejection. The presence of a G→A polymorphism at position −308 in the promoter region of the TNF-&agr; gene increased its transcription 6- to 7-fold. A similar polymorphism at position −1082 of the IL-10 promoter results in decreased production of IL-10 protein. In this study we have determined whether the single nucleotide polymorphisms in the promoter regions of the TNF-&agr; and IL-10 genes can predict the outcome of the allograft in liver recipients. Methods. DNA was extracted from whole blood of liver recipients. The genotype of the patients was determined by polymerase chain reaction using sequence-specific primers. The level of TNF-&agr; and IL-10 protein was measured by ELISA after stimulation of peripheral blood mononuclear cells with concanavalin A. Results. There was significant correlation between acute cellular rejection and the presence of the −308A polymorphism (P <0.001), with 8 of 13 patients with the TNF-&agr; polymorphism having evidence of acute rejection. Cell stimulation studies revealed that the level of TNF-&agr; protein produced by patients with liver rejection was significantly higher than for patients without rejection (P =0.001). There were no strong associations between the presence of the IL-10 polymorphisms and rejection (P =0.71). Conclusions. This study adds to the understanding of the role of cytokine polymorphisms in liver transplants. The data suggest that cytokine promoter polymorphisms may be a risk factor associated with allograft rejection in the liver.

Evidence of Borrelia Autoimmunity-Induced Component of Lyme Carditis and Arthritis

ABSTRACT We investigated the possibility that manifestations of Lyme disease in certain hosts, such as arthritis and carditis, may be autoimmunity mediated due to molecular mimicry between the bacterium Borrelia burgdorferi and self-components. We first compared amino acid sequences of Streptococcus pyogenes M protein, a known inducer of antibodies that are cross-reactive with myosin, and B. burgdorferi and found significant homologies with OspA protein. We found that S. pyogenes M5-specific antibodies and sera from B. burgdorferi-infected mice reacted with both myosin and B. burgdorferi proteins by Western blots and enzyme-linked immunosorbent assay. To investigate the relationship between self-reactivity and the response to B. burgdorferi, NZB mice, models of autoimmunity, were infected. NZB mice infected with B. burgdorferi developed higher degrees of joint swelling and higher anti-B. burgdorferi immunoglobulin M cross-reactive responses than other strains with identical major histocompatibility complex (DBA/2 and BALB/c). These studies reveal immunological cross-reactivity and suggest that B. burgdorferi may share common epitopes which mimic self-proteins. These implications could be important for certain autoimmunity-susceptible individuals or animals who become infected with B. burgdorferi.

Oncoproteins and proliferation markers in synovial sarcomas: a clinicopathologic study of 19 cases

Abstract Purpose. The objective of this study was to evaluate synovial sarcomas for the expression of oncogenic proteins (Her2/neu, EGFR, Bcl-2, p53) and proliferation markers (Ki-67, Topoisomerase 2α), as possible markers of prognostic significance. Methods. From 17 patients with synovial sarcomas 19 tumors (15 primary, 2 recurrent, and 2 metastatic) were selected on the basis of characteristic histology, the expression of at least one epithelial marker, and/or the presence of t(X;18). Adequate follow-up was available in all cases. Results. The tumors were tested immunohistochemically and were found to express multiple oncogenic proteins. Four of 19 synovial sarcomas (21%) demonstrated nuclear over-expression of p53 protein; 18 of 19 tumors (94%) stained positive for Bcl-2; and 13 of 19 tumors (68%) were immunoreactive with EGFR. Of particular interest was the frequent expression of Her2/neu, an oncogenic protein more commonly observed in epithelial neoplasms. Ten of 19 tumors (52%, 7 monophasic and 3 biphasic) showed positive cytoplasmic and membranous staining with Her2/neu (HercepTest, DAKO). The staining intensity ranged from 1+ to 2+. Cellular expression of Her2/neu was independent of EGFR positivity and showed no association with proliferative activity of the tumors. FISH analysis of eight positive cases showed no evidence of Her2/neu gene amplification. Among the non-metastatic tumors, we found a significant correlation between Ki-67 and Topoisomerase 2α. Spearmans correlation co-efficient was 0.86 with P=0.001 (n=17). Conclusions. In this relatively small series of cases, we found no definite correlation between the over-expression of Her2/neu and clinical outcome. The over-expression of p53 was significantly associated with clinical outcome (Fishers exact test, P=0.02).

Comparison study for identifying promoter allelic polymorphism in interleukin 10 and tumor necrosis factor alpha genes.

Cytokines such as tumor necrosis factor (TNF)-&agr; and Interleukin (IL)-10 play significant roles in autoimmunity and transplantation tolerance. Allelic polymorphisms that occur in the regulatory regions of these cytokine genes are closely associated with acute and chronic transplant rejection. The presence of a G-to-A polymorphism at position −308 in the promoter region of the TNF-&agr; gene can increase transcription six-to sevenfold. Likewise, the G-A polymorphism at position −1082 of the IL-10 promoter results in lower levels of IL-10 protein. Accordingly, a genotype that dictates the production of high levels of TNF-&agr; with low IL-10 capabilities is most likely to generate an inflammatory environment that is less receptive to the transplant. The potential for determining a patients haplotype before transplantation may be an effective way of monitoring the post-transplant status of such patients. A variety of methodologies that address the detection of mutations have been used both in research and clinical diagnostic tests. This study analyzes the genetic variations in cytokines using two methodologies: the traditional allele-specific oligonucleotide (ASO) polymerase chain reaction (PCR) and the newer and more flexible Invader technology. The sensitivity and specificity of the Invader assay for simultaneous investigation of multiple targets makes it a useful tool in such analyses.

IL-10 production in a CD5+ B cell lymphoma arising in a CD4 monoclonal antibody-treated SJL mouse.

A majority of SJL mice develop spontaneous reticulum cell sarcomas (RCS) at about 1 year of age which can be transplanted into young SJL recipients. Previous studies have shown that RCS tumors are of B cell lineage, and that the development of these lymphomas and their subsequent growth depends upon host-derived T helper cell factors. In vivo treatment of SJL mice with anti-CD4 monoclonal antibody (mAb) prevents the development of the characteristic B lymphomas. Most of the mAb-treated animals were tumor free and had a significantly prolonged life span. However, one such CD4 mAb-treated mouse developed a transplantable IgM+ CD5+ B cell lymphoma (designated NJ101), which has not previously been described in SJL/J mice. NJ101 is clonal on the basis of a discrete non-germ line Ig heavy chain gene rearrangement by Southern blot analysis. Unlike the sIg- CD5- transplantable RCS-X cell line, the IgM+ CD5+ NJ101 lymphoma cells will grow in immuno-compromised hosts, such as irradiated recipients or in recipients treated with CD4 mAb in vivo. The RCS (B cell) lymphoma requires CD4+ T cells for progressive growth, whereas the growth of the CD5+ B lymphoma cells is enhanced by the removal of such cells. Thus, CD5+ B cell clonal development may be aided by the removal of regulatory T cells and/or the malignant CD5+ B cells may produce their own growth factors in an autocrine manner. Examination of IL-10 message by quantitative polymerase chain reaction techniques indicate that the CD5+ B lymphoma cells produce increased levels of IL-10 relative to normal LN cells or purified RCS lymphoma cells. These results suggest that two different types of B cell tumors, both of which can develop in SJL mice, have different growth requirements. Furthermore, treatment to prevent the occurrence of the characteristic RCS malignancy of SJL mice may lead to the development of another form of B cell neoplasia.

Coamplification of HIV-1 Proviral DNA and Viral RNA in Assays Used for Quantification of HIV-1 RNA

ABSTRACT Elevated HIV-1 viral load (VL) observed in specimens frozen in situ in plasma preparation tubes (PPTs) compared to EDTA plasma specimens may affect therapeutic monitoring of HIV-infected patients. The increase in viral load is cell associated and minimized when plasma from the PPT is aspirated or recentrifuged prior to freezing. This study investigates the contribution of integrated HIV-1 proviral DNA to elevated VL in the quantification of HIV-1 RNA in plasma. Fifty paired specimens collected in EDTA tubes and PPTs frozen in situ were used for analysis. HIV-1 VL was measured using the COBAS Amplicor Monitor ultrasensitive test version 1.5. Contaminating proviral DNA was detected using a nested PCR targeting the Alu repeat in human genomic DNA and HIV pol gene simultaneously. Treatment of the specimen with DNase resulted in significantly lower quantifiable HIV-1 RNA in specimens from PPTs compared to the corresponding EDTA tubes (P = 0.004). After the RNA was destroyed by heat treatment, the mean HIV-1 RNA VL decreased by 79% in the EDTA tube compared to 65% in the PPT. The nested PCR amplified integrated proviral DNA in nucleic acid extracted from plasma in PPT and EDTA specimens with high viral load values. Likewise, a semiquantitative densitometric analysis revealed that the total amount of genomic DNA in the PPT was higher than that in the EDTA tube. Our investigation clearly shows that both proviral DNA and intracellular RNA are amplified simultaneously in the COBAS Amplicor HIV-1 Monitor assay and that proviral DNA contributes to the elevated VL in plasma frozen in PPTs.

C282Y Mutation and Hepatic Iron Status in Hepatitis C and Cryptogenic Cirrhosis

BACKGROUND Increased iron deposition in liver is seen in both primary and secondary hemochromatosis. However, it is not uncommon to see significant iron deposition in a liver biopsy, explant, or autopsy specimen without any significant clinical risk factor. Because of the discovery of the candidate gene (HFE) for hereditary hemochromatosis, we may now be able to screen high-risk patient populations for the abnormal mutation (C282Y). MATERIALS AND METHODS In this study we analyzed the livers of 50 transplant patients with a diagnosis of either hepatitis C cirrhosis or cryptogenic cirrhosis for the prevalence of the more common C282Y mutation of the HFE gene and correlated the findings to hepatic iron concentration. RESULTS Of the 26 cases of hepatitis C cirrhosis, 3 were found to be heterozygous for the C282Y mutation. Of the 22 cases of cryptogenic cirrhosis, 1 was found to be heterozygous for the C282Y mutation. Stainable iron was increased in hepatitis C cirrhosis (76.9%) as compared to cryptogenic cirrhosis (50%) (P =. 05). Of the 3 heterozygotes with hepatitis C cirrhosis, 2 showed hepatic iron concentrations of 3+ and 4+, and 1 showed 1+. CONCLUSIONS We conclude that patients with hepatitis C have an increased tendency to accumulate iron in the liver, and mutations in the HFE gene play a minor role in hepatic accumulation of iron in these patients.

Cloning and characterization of the 5' flanking region of the HGFIN gene indicate a cooperative role among p53 and cytokine-mediated transcription factors: relevance to cell cycle regulation.

HGFIN, previously identified as nmb, and its homologs, osteoactivin are single transmembrane protein that is expressed in differentiated immune cells, and are linked to tumor progression. These dichotomous roles suggest that HGFIN could be linked to cell cycle regulation. We hypothesize that HGFIN is linked to different phases of cell cycle regulation via specific transcription factors. This study cloned and analyzed two fragments in the 5? flanking region of HGFIN: HGFIN-RM/2.0: 2.0 kb upstream of Exon 1; HGFIN-RM/1.5: 5? deletion (500 bp) of HGFIN-RM/2.0. Computer analyses indicated that HGFIN has unique upstream sequence with eight potential p53 sites. Electrophoretic mobility shift assay with Cy3-labeled PCR fragments indicated that p53 could interact with fragments encompassing p53 consensus regions. Reporter gene activities with HGFIN-RM/2.0 and HGFIN-RM/1.5 in cells with different p53 levels showed that p53 is relevant to HGFIN activities. Studies with modified T47D in which cytokine production was downregulated, but with p53 level similar to parental line showed synergism between p53 and mediators of cytokine in the regulation of HGFIN. In summary, p53 cooperate with cytokine-mediated transcription factors to regulate the expression of HGFIN.