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Biomedical subjects

Angus G Dalgleish

Publications and source records attributed to Angus G Dalgleish.

At least 19 recordsLinked to original sources
PubMed2007

Doxycycline induces caspase-dependent apoptosis in human pancreatic cancer cells.

Doxycycline (DC) belongs to the tetracycline family of antibiotics and has been used clinically for over 5 decades. Despite advances in understanding the molecular pathogenesis of pancreatic cancer, no chemotherapy course has shown significant effectiveness. Hence new treatments are needed. In this study we report the pro-apoptotic effects of DC in 2 pancreatic adenocarcinoma cell lines, T3M4 and GER. Cell proliferation was measured using the SRB protein dye. Induction of apoptosis was detected using ELISA. Caspase activation was detected using either immunoblotting or a colorimetric assay based on cleavage of caspase-associated substrates. Expression of proteins and post-translational modifications were determined using immunoblotting. Treatment of pancreatic cancer cells with DC reduces their proliferation. This reduction is, at least partly, due to increased caspase-dependent apoptosis involving activation of caspase3, caspase7, caspase8, caspase9, caspase10 and increased levels of FADD. Inhibition of caspase8 or caspase10 but not caspase9 significantly decreases DC-induced apoptosis in both cell lines. Furthermore treatment of pancreatic cancer cells with DC increases protein levels of Bax and phosphorylation of members of the p38MAPK pathway such as p38MAPK, MKK3/6 and MAPKAPK2. These results provide an insight into mechanisms behind the pro-apoptotic effects of DC in pancreatic cancer cells.

Adenocarcinoma↗
PubMed2006

Origins of HIV and the evolution of resistance to AIDS.

The cross-species transmission of lentiviruses from African primates to humans has selected viral adaptations which have subsequently facilitated human-to-human transmission. HIV adapts not only by positive selection through mutation but also by recombination of segments of its genome in individuals who become multiply infected. Naturally infected nonhuman primates are relatively resistant to AIDS-like disease despite high plasma viral loads and sustained viral evolution. Further understanding of host resistance factors and the mechanisms of disease in natural primate hosts may provide insight into unexplored therapeutic avenues for the prevention of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Investigation of the mechanisms by which EB1089 abrogates apoptosis induced by 9-cis retinoic acid in pancreatic cancer cells.

OBJECTIVES: Previous research has shown that the retinoid 9-cis retinoic acid (RA) promotes apoptosis in pancreatic cancer cells. The vitamin D analog EB1089 does not. Furthermore, cotreatment of cells with 9-cis RA and EB1089 abrogates apoptosis. To explain this, we studied the regulation of proteins involved in apoptotic signaling pathways in pancreatic cancer cells. METHODS: The pancreatic adenocarcinoma cell line T3M4 was used. Cell proliferation was measured using the SRB protein dye assay. Induction of apoptosis was evaluated using an ELISA assay. Caspase activation was detected using a colorimetric assay based on cleavage of a caspase-associated substrate. Regulation of protein levels and posttranslational events were detected using immunoblotting. RESULTS: We confirm that EB1089 diminishes apoptosis induced by 9-cis RA in T3M4 cells. We extend the study to show that EB1089 abrogates increases, induced by 9-cis RA, in caspase activation, p27Kip1 protein levels, Bim and Bax protein levels and in Bax/Bcl2 ratio. In addition, the CDKI p21Waf1 and CAII, a differentiation marker for pancreatic cancer cells are also differentially regulated. CONCLUSIONS: These results suggest that the inhibitory effects of EB1089 on 9-cis RA-induced apoptosis lie upstream of caspase activation and could be associated with reduction of p27Kip1 protein levels.

Adenocarcinoma↗
PubMed2006

Inflammation and cancer: the role of the immune response and angiogenesis.

The link with chronic inflammation and cancer has been recognized for certain cancers for several decades. However, only recently has the biology of chronic inflammation begun to be understood, to the point that it may play a major role in tumour development. The biology of chronic inflammation has many similarities with that of wound healing. In particular, local cell mediated immunity is attenuated and angiogenesis is increased along with other growth factors. When present long-term, this provides the ideal environment for mutated cells to be nurtured and escape immune surveillance. It is of note that this process still appears to take two or three decades, as witnessed by the close association between chronic ulcerative colitis and colon cancer as well as chronic hepatitis and hepatocellular carcinoma. Closer study of the inflammatory pathways show the close interaction with apoptosis and anti-apoptotic pathways, as well as the main tumour suppressor genes, such as p53, as well as a number of growth factors, such as the insulin-like growth factor. A full study of these processes reveals that there are key molecules in these pathways which may provide therapeutic as well as anti-inflammatory targets.

Apoptosis↗
PubMed2005

The biological effects of syngeneic and allogeneic cytokine-expressing prophylactic whole cell vaccines and the influence of irradiation in a murine melanoma model.

Allogeneic whole tumour cell vaccines are inherently practical compared with autologous vaccines. Cell lines are derived from allogeneic tumour, grown in bulk and then administered as a vaccine to the patient, following irradiation, which not only prevents any replication but also enhances antigen presentation. Protection is believed to occur through the presentation of antigens shared between the syngeneic and allogeneic tumours. Although cytokine-transfected tumour whole cell vaccines have been used clinically, little data is available comparing the effects of immunomodulatory cytokine-transfection directly on the same cells when used as both an allogeneic and autologous vaccine. To address this, weakly immunogenic B16-F10 (H-2b) murine melanoma was transfected to secrete either GM-CSF, IL-4 or IL-7. Prophylactic vaccination of both syngeneic C57/BL6 (H-2b) (B6) and allogeneic C3H/Hej (H-2k) (C3H) mice showed the effects of transfected cytokine varied between models. Both GM-CSF and IL-7 significantly (P<0.05) increased the levels of protection within syngeneic B6 mice, but had a diminished effect (P>0.05) within C3H allogeneic mice. Allogeneic B16-F10 cells and syngeneic K1735 cells generated CTL against K1735 suggesting cross-reactive immunity. Using cells labeled with fluorescent dye we demonstrate that irradiated vaccines, of either syngeneic or allogeneic origin, appear to generate potent immune responses and fragments of either vaccine remain at the injection site for up to 9 days. This study shows that protection can be enhanced in vivo by using transfected cytokine, but suggests that irradiated whole cell vaccines, of either tissue-type, are rapidly processed. This leads to the conclusion that the cytokine effects are transient and thus transfection with cytokine may be of limited long-term use in situ.

Animals↗
PubMed2005

Orally administered lenalidomide (CC-5013) is anti-angiogenic in vivo and inhibits endothelial cell migration and Akt phosphorylation in vitro.

The thalidomide analogue and immunomodulatory drug (IMiD) lenalidomide (CC-5013, REVLIMID) is emerging as a useful treatment for a number of cancers and has recently entered phase III trials for multiple myeloma. It has been suggested that the anti-tumor effect of lenalidomide is related to its anti-angiogenic potency. In this regard, we have previously shown that lenalidomide inhibits angiogenesis in both rat and human in vitro models but does not affect endothelial cell proliferation. We now show that oral administration of lenalidomide attenuates growth factor-induced angiogenesis in vivo; the rat mesenteric window assay was utilized to show that lenalidomide significantly inhibits vascularization in a dose-dependent manner. We also found that lenalidomide significantly inhibits growth factor-induced endothelial cell migration. This correlates with the inhibitory effect of lenalidomide on growth factor-induced Akt phosphorylation, thereby providing a potential mechanism for its anti-migratory and subsequent anti-angiogenic effects. These data further support the use of lenalidomide as an orally administered drug for the effective treatment of angiogenesis-dependent conditions, including cancer, and suggest a potential mechanism of action.

Administration, Oral↗
PubMed2004

Successful live cell harvest from bisected sentinel lymph nodes research report.

Sentinel lymph nodes provide an excellent opportunity to study early immune responses to cancer. However, harvesting live cells has not previously been possible, because it conflicts with the need to preserve tissue for histological interpretation. This study used scrape cytology on 26 sentinel and 8 non-sentinel nodes, harvested from 17 stage I/II melanoma patients undergoing sentinel node biopsy. Numbers of viable cells harvested before and after cryopreservation were measured and the effect on subsequent histology assessed. The mean number of cells harvested from 26 sentinel nodes was 7.06 x 10(6) (range 0.1-32.2), with a mean viability of 99.5% (range 87-100, lower 95% CI 98.5%). Furthermore, counts and viabilities were well maintained after cryopreservation. Flow cytometry confirmed CD3+, CD20+ and lineage-1-/HLA-DR+ subpopulations, consistent with T-lymphocytes, B-lymphocytes and dendritic cells, respectively. Importantly, there was no discernible change in histological detail and the proportion of positive sentinel nodes remained unchanged. This technique will allow more functional and quantitative approaches to sentinel lymph node research.

Antigens, CD20↗
PubMed2004

Possession of human leucocyte antigen DQ6 alleles and the rate of CD4 T-cell decline in human immunodeficiency virus-1 infection.

Polymorphism amongst the human leucocyte antigen (HLA) class II genes could influence antigen presentation and the ability to control human immunodeficiency virus (HIV)-1 by modulating the virus specific CD4 immune response. To examine the effect of such polymorphisms on disease progression, we studied a cohort of 46 HIV-1 infected long-term non-progressors (LTNPs), 87 intermediate progressors (IPs) and 26 rapid progressors. Kaplan-Meier survival analysis of all patients in the cohort on time to a CD4 count less than 350 cells/ micro l, showed a trend for a slower rate of CD4 decline in patients with, compared to those without, the DRB1*15-DQB1*06 haplotype (hazard ratio (HR) 0.69, 95% CI 0.46-1.01, P = 0.06). A similar effect was not observed with the DRB1*13-DQB1*06 haplotype (HR 1.18, 95% CI 0.75-1.88, P = 0.46), but was observed when DQB1*06 alleles were considered irrespective of their DR association (HR 0.74, 95% CI 0.52-1.05, P = 0.06). Major HLA-DQ6 alleles encode aspartate (Asp) at position 57 on the DQbeta chain, a phenotype associated with protection from other immune disorders. We therefore examined the frequency of all DQbeta57 Asp+ alleles, but could not detect a significant effect on the rate of CD4 decline. To examine whether the genotype associated with slower CD4 decline was over-represented in patients with a slow rate of disease progression, we conducted a categorical analysis of a subset of patients with an extended follow-up of 14+years. We found a higher proportion of LTNPs at 14+ years possessed the DRB1*15-DQB1*06 haplotype compared to IPs at 14+ years (38.46 versus 18.18%), though this difference did not reach statistical significance. When DQB1*06 alleles irrespective of their DR association were considered, the protective effect was greater (76.9% LTNPs versus 18.18% IPs, P = 0.04). Our results highlight the potential protective effect of HLA DQB1*06 alleles on the course of HIV disease.

Alleles↗
PubMed2004

Dendritic cell immunotherapy for urological cancers using cryopreserved allogeneic tumour lysate-pulsed cells: a phase I/II study.

OBJECTIVE: To assess the feasibility, toxicity and immunogenicity of dendritic cell (DC)-based immunotherapy in patients with advanced urological cancers. PATIENTS AND METHODS: Patients with hormone-refractory prostate cancer (11) and metastatic renal cell carcinoma (five) received 1-3 x 10(6) intradermal allogeneic tumour lystate-pulsed DCs fortnightly for six vaccinations then monthly until disease progression. Intradermal keyhole limpet haemocyanin was injected near the DCs as the adjuvant. DC vaccine was prepared from buffy coats, then lysate-pulsed, cryopreserved in aliquots, and tested for phenotypic expression and activity in an allogeneic mixed lymphocyte reaction before clinical use. RESULTS: There was no evidence of significant toxicity from vaccine or adjuvant. Delayed-type hypersensitivity skin testing and biopsy revealed a cellular infiltrate to intradermal re-challenge to tumour lysate and adjuvant in almost all patients. In addition, there was increased expression of T helper type 1 cytokines, interferon-gamma-expressing T cell by ELISPOT analysis, but also interleukin-10 in a few patients. Vaccination resulted in a reduction in the level of prostate-specific antigen (PSA) in one patient, a reduction in PSA velocity in a further man and an increased PSA doubling time in six. Two of five patients with renal cell carcinoma had stabilization of disease. CONCLUSION: The cryopreservation and repeated administration of DC vaccine was feasible and not toxic. There was evidence of induction of both humoral and cellular immunity to vaccine and adjuvant in most patients. The use of sequential aliquots of identical cryopreserved vaccine will ensure quality control and greatly facilitate future clinical studies in terms of consistency of vaccine administered and the provision of primed DCs for in vitro assessment of response.

Adjuvants, Immunologic↗
PubMed2004

Thalidomide-derived immunomodulatory drugs as therapeutic agents.

Thalidomide, a drug originally used to treat morning sickness, was removed from the market place in the early 1960s after it was found to cause serious congenital birth defects. However, thalidomide has recently been investigated in a new light following its activity in a number of chronic diseases. Moreover, like thalidomide itself, its second-generation immunomodulatory drug (IMiD) analogues have been shown to act as powerful anticancer agents and are clearly active in the treatment of patients with relapsed multiple myeloma. These new drugs, in particular the second-generation IMiDs, lenalidomide (CC-5013, REVLIMID; Celgene Corp., NJ, USA) and CC-4047 (ACTIMID; Celgene Corp.), offer improvements over thalidomide (a first-generation IMiD) in terms of efficacy and safety in human studies. The key to the therapeutic potential of IMiDs lies in the fact that the drugs have multiple mechanisms of action, which may produce both anti-inflammatory and antitumour effects. These effects are probably contextual, depending both on the cell type and the stimulus involved. Mechanisms associated with IMiD activity include TNF-alpha-inhibitory, T cell costimulatory and antiangiogenic activities. Studies of the mechanisms of action of these drugs are ongoing and will facilitate the continued development of this class of compound in a number of diseases.

Anti-Inflammatory Agents↗
PubMed2004

Cancer vaccines as a therapeutic strategy.

The concept of cancer vaccines is as a therapeutic strategy to immunize the body against cancer antigens that may not be presented by the cancer itself, due to the marked immunosuppressive effects of the disease, which has been demonstrated in many different tumors.

Animals↗
PubMed2003

Heated tumour cells of autologous and allogeneic origin elicit anti-tumour immunity.

Vaccination with established tumour cell lines may circumvent the problem of obtaining autologous tumour cells from patients, but may also need immunological adjuvants. Up-regulation of heat shock proteins within tumour cell vaccines has resulted in increased immunogenicity in some models, but this has yet to be demonstrated for allogeneic (MHC-disparate) cell vaccines. This was investigated here using a rat model for prostate tumour cell vaccination. Heating of tumour cells (42 degrees C, 1 h) elicited significant increases in HSP70 expression. Vaccination with heated autologous PAIII cells elicited protection against PAIII challenge in 60% of rats >50 days compared to 0% with unheated vaccine and was associated with an increased Th1 (IFNgamma) immune response. Heated allogeneic MLL cells elicited significant protection against PAIII challenge, in contrast to unheated cells. The principle was confirmed in two mouse models, although the allogeneic melanoma vaccine K1735 elicited the best protection when heated and administered mixed with autologous dendritic cells. Thus, while heating of vaccine cells in some models is highly beneficial, and is a means of enhancing immunogenicity without genetic modification or inclusion of potentially toxic adjuvants, additional immune enhancement may be required.

Animals↗
PubMed2003

A novel subclass of thalidomide analogue with anti-solid tumor activity in which caspase-dependent apoptosis is associated with altered expression of bcl-2 family proteins.

Thalidomide is clinically useful in a number of cancers. Antitumor activity may be related to a number of known properties, including anti-tumor necrosis factor (TNF)-alpha and T-cell costimulatory and antiangiogenic activities. However, it may also involve direct antitumor effects. A series of second generation thalidomide analogues have been separated into two distinct groups of compounds, each with enhanced therapeutic potential, i.e., SelCIDs, which are phosphodiesterase (PDE) type IV inhibitors, and IMiDs, which have unknown mechanism(s) of action. We report here our efforts to determine direct antitumor effects of thalidomide and compounds from both groups. We found that one of the SelCID analogues (SelCID-3) was consistently effective at reducing tumor cell viability in a variety of solid tumor lines but had no effect on non-neoplastic cells. The antitumor activity was independent of known PDE4 inhibitory activity and did not involve cAMP elevation. Growth arrest was preceded by the early induction of G(2)-M cell cycle arrest, which led to caspase 3 mediated apoptosis. This was associated with increased expression of pro-apoptotic proteins and decreased expression of antiapoptotic bcl-2. Furthermore, extensive apoptosis in vivo was detected during SelCID-3-mediated inhibition of tumor growth in a murine xenotransplantation cancer model. Our results suggest that SelCID-3 represents a novel antitumor agent distinct from thalidomide and from previously characterized analogues with therapeutic potential against a range of solid tumors. This effect appears to be mediated via alterations in the expression of bcl-2 family proteins.

Animals↗
PubMed2003

Thalidomide analogs as emerging anti-cancer drugs.

Recently, it has been demonstrated that a number of novel thalidomide analogs possess anti-cancer properties due to their T cell co-stimulatory, anti-angiogenic and/or anti-inflammatory effects. Based on such effects, a class of thalidomide analogs known as Immunomodulatory Drugs (IMiDs) have recently entered into phase I clinical trials for the treatment of a number of cancers. The lead IMiD CC-5013 (referred to clinically as REVIMID) is now entering phase III clinical trials for multiple myeloma and metastatic melanoma, while CC-4047 (ACTIMID) is currently under investigation in phase I/II and II trials for multiple myeloma and prostate cancer, respectively. The other group of compounds, classified as Selective Cytokine Inhibitory Drugs (SelCIDs), do not co-stimulate T cells, but have anti-inflammatory and anti-angiogenic properties. Moreover, a subset of SelCIDs has been found to possess direct anti-tumor activity both in vitro and in vivo. This minireview highlights the various mechanisms of action associated with these compounds and their subsequent clinical development. The enhanced efficacy and lower side-effect profiles of the analogs in comparison to thalidomide make the use of these agents very attractive as novel anti-cancer agents.

Adjuvants, Immunologic↗
PubMed2003

Thalidomide derived immunomodulatory drugs (IMiDs) as potential therapeutic agents.

Thalidomide is known to be effective in the treatment of a number of conditions, including leprosy and various cancers. The exact mechanisms of action remain unclear although these are known to include anti-tumour necrosis factor (TNF)-alpha, T cell costimulatory, anti-angiogenic and anti-tumour activities. However, thalidomide is being superceded by novel structural derivatives which have been designed to have improved immunomodulatory activity and side effect profiles. These are currently being characterised and some are entering the clinic in phase I/II studies. One novel group of structural analogues are classified as the Immunomodulatory Drugs (IMiDs). This review describes the emerging immunological, anti-angiogenic and direct anti-tumour properties of thalidomide and the characterisation and clinical application of its IMiD analogues. We describe the laboratory studies which have led to the characterisation and development of IMiDs into potentially clinically relevant drugs. Early trial data suggests that these compounds may themselves become established therapies, particularly in certain cancers. Furthermore, ongoing studies will determine how best to apply these compounds to the appropriate clinical settings. We will describe the various clinical studies of lead compounds that are in progress and speculate as to the potential and future development of these exciting compounds.

Adjuvants, Immunologic↗
PubMed2003

Angiogenesis inhibitors in cancer therapy.

The formation of new blood vessels is essential for tumor growth and progression. Angiogenesis inhibitors have been demonstrated to block tumor growth and/or metastasis. Although initial clinical data have been disappointing, new strategies to increase the efficacy of these drugs have ensured their ongoing clinical development. This review highlights the broad spectrum of angiogenesis inhibitors under investigation in both preclinical and clinical studies. From 'natural' inhibitors to thalidomide analogs, the number of compounds in development is extensive. Elucidating the mechanisms of action will enable their use in conjunction with existing/other novel therapies, thereby maximizing the potential efficacy of angiogenesis inhibitors to fulfill their promise in patients with cancer.

Angiogenesis Inhibitors↗