Gene therapy of ovarian cancer with IFN-alpha-producing fibroblasts: comparison of constitutive and inducible vectors.

Ovarian cancer represents a malignancy suitable for cell and gene therapy approaches owing to its containment within the peritoneal cavity, even at advanced tumor stages. As regulation of transgene expression would be preferable for conducting clinical trials for reasons of safety, we investigated whether intraperitoneal (i.p.) administration of retroviral vector-transduced fibroblasts encoding murine interferon-alpha (IFN-alpha) could have therapeutic activity, and compared its effect with the antitumor effects of fibroblasts producing IFN-alpha under a rapamycin analogue (AP21967)-inducible promoter. Human and murine fibroblasts were recruited into the solid component of transplantable ovarian cancer-grown i.p. in severe combined immunodeficiency mice. Multiple administrations of fibroblasts producing IFN-alpha in a constitutive manner showed therapeutic efficacy, leading to significant prolongation of survival in the majority of animals, associated with inhibition of tumor angiogenesis. Compared to cells transduced by the constitutive vector, fibroblasts transduced by the inducible vector released twofold higher IFN-alpha levels in vitro, following induction by AP21967, and production of the cytokine was under pharmacologic control both in vitro and in vivo. However, these cells elicited only modest therapeutic effects in vivo. Overall, these findings indicate that intracavitary IFN-alpha gene therapy using engineered fibroblasts requires sustained production of IFN-alpha to achieve durable antitumor effects.

Functional categories of TP53 mutation in colorectal cancer: results of an International Collaborative Study.

BACKGROUND: Loss of TP53 function through gene mutation is a critical event in the development and progression of many tumour types including colorectal cancer (CRC). In vitro studies have found considerable heterogeneity amongst different TP53 mutants in terms of their transactivating abilities. The aim of this work was to evaluate whether TP53 mutations classified as functionally inactive (< or=20% of wildtype transactivation ability) had different prognostic and predictive values in CRC compared with mutations that retained significant activity. MATERIALS AND METHODS: TP53 mutations within a large, international database of CRC (n = 3583) were classified according to functional status for transactivation. RESULTS: Inactive TP53 mutations were found in 29% of all CRCs and were more frequent in rectal (32%) than proximal colon (22%) tumours (P < 0.001). Higher frequencies of inactive TP53 mutations were also seen in advanced stage tumours (P = 0.0003) and in tumours with the poor prognostic features of vascular (P = 0.006) and lymphatic invasion (P = 0.002). Inactive TP53 mutations were associated with significantly worse outcome only in patients with Dukes' stage D tumours (RR = 1.71, 95%CI 1.25-2.33, P < 0.001). Patients with Dukes' C stage tumours appeared to gain a survival benefit from 5-fluorouracil-based chemotherapy regardless of TP53 functional status for transactivation ability. CONCLUSIONS: Mutations that inactivate the transactivational ability of TP53 are more frequent in advanced CRC and are associated with worse prognosis in this stage of disease.

Large genomic deletions inactivate the BRCA2 gene in breast cancer families.

BACKGROUND: BRCA1 and BRCA2 are the two major genes responsible for the breast and ovarian cancers that cluster in families with a genetically determined predisposition. However, regardless of the mutation detection method employed, the percentage of families without identifiable alterations of these genes exceeds 50%, even when applying stringent criteria for family selection. A small but significant increase in mutation detection rate has resulted from the discovery of large genomic alterations in BRCA1. A few studies have addressed the question of whether BRCA2 might be inactivated by the same kinds of alteration, but most were either done on a relatively small number of samples or employed cumbersome mutation detection methods of variable sensitivity. OBJECTIVE: To analyse 121 highly selected families using the recently available BRCA2 multiplex ligation dependent probe amplification (MLPA) technique. RESULTS: Three different large genomic deletions were identified and confirmed by analysis of the mutant transcript and genomic characterisation of the breakpoints. CONCLUSIONS: Contrary to initial suggestions, the presence of BRCA2 genomic rearrangements is worth investigating in high risk breast or ovarian cancer families.

Reduced seroprevalence of Kaposi's sarcoma-associated herpesvirus (KSHV), human herpesvirus 8 (HHV8), related to suppression of Anopheles density in Italy.

In two formerly malarious parts of Italy, age-related seroprevalence rates of Kaposi's sarcoma-associated herpesvirus [human herpesvirus 8 (KSHV/HHV8)] were determined from local blood donors and correlated with periods of vector control during anti-malaria campaigns. In Veneto, decreased KSHV/HHV8 seroprevalence in the 1951-1955 birth cohort coincides with the peak of DDT house-spraying. In Sardinia, where larviciding augmented indoor DDT-spraying, a significant drop of KSHV/HHV8 seroprevalence between 1945 and 1950 and 1951-1955 birth cohorts (P = 0.0046) coincides with suppression of the malaria vector Anopheles labranchiae Falleroni (Diptera: Culicidae). These results are consistent with age-related association between KSHV/HHV8 seroprevalence rates in native/resident populations and the density of malaria vectors in Veneto and Sardinia. This example supports our 'promoter arthropod' hypothesis on the role of haematophagous insects [putatively blackflies (Simuliidae), sandflies (Phlebotominae) and biting midges (Ceratopogonidae), as well as mosquitoes] when their bites induce hypersensitivity and immunosuppression, potentiate KSHV/HHV8 transmission via human saliva (when insect bite lesions are licked by another person whose saliva carries the virus) and may facilitate Kaposi's sarcoma.

Tumor outgrowth in peripheral blood mononuclear cell-injected SCID mice is not associated with early Epstein-Barr virus reactivation.

Epstein-Barr virus (EBV)-positive B-cell lymphoproliferative disease develops in severe combined immunodeficient (SCID) mice inoculated with peripheral blood mononuclear cells (PBMC) from EBV(+) individuals (SCID/hu mice). In this study, we investigated the contribution of EBV reactivation and de novo infection of B lymphocytes to tumor outgrowth in SCID/hu mice. Evaluation of BZLF-1, an early EBV activation transcript, in cells recovered from the mouse peritoneal cavity within 16 days following PBMC transfer did not reveal EBV reactivation, while BZLF-1 expression was only detected in tumor masses or in vitro established lymphoblastoid cell lines. To confirm these data by a different strategy, we coinjected PBMC from seropositive donors with purified B cells from seronegative donors of different sex. Fluorescence in situ hydridization analysis of the resulting tumor masses disclosed that the overwhelming majority of lymphoma cells originated from the seropositive donor, implying that no substantial in vivo production and transmission of virus had occurred. Further, treatment of SCID/hu mice with ganciclovir did not prevent lymphoma development. Our results suggest that in the SCID/hu mouse, early EBV replication and secondary infection of bystander B cells does not occur, and that the direct outgrowth of the transformed B lymphocytes present within the PBMC inoculum is the predominant mechanism, which leads to lymphoma generation in this experimental model.

Differential effects of angiostatin, endostatin and interferon-alpha(1) gene transfer on in vivo growth of human breast cancer cells.

The administration of different angiogenesis inhibitors by gene transfer has been shown to result in inhibition of tumor growth in animal tumor models, but the potency of these genes has been only partially evaluated in comparative studies to date. To identify the most effective anti-angiogenic molecule for delivery by retroviral vectors, we investigated the effects of angiostatin, endostatin and interferon(IFN)-alpha(1) gene transfer in in vivo models of breast cancer induced neovascularization and tumor growth. Moloney leukemia virus-based retroviral vectors for expression of murine angiostatin, endostatin and IFN-alpha(1) were generated, characterized, and used to transduce human breast cancer cell lines (MCF7 and MDA-MB435). Secretion of the recombinant proteins was confirmed by biological and Western blotting assays. Their production did not impair in vitro growth of these breast cancer cells nor their viability, and did not interfere with the expression of angiogenic factors. However, primary endothelial cell proliferation and migration in vitro were inhibited by supernatants of the transduced cells containing angiostatin, endostatin, and IFN-alpha(1). Stable gene transfer of the IFN-alpha(1) cDNA by retroviral vectors in both MCF7 and MDA-MB435 cells resulted in a marked and long-lasting inhibition of tumor growth in nude mice that was associated with reduced vascularization. Endostatin reduced the in vivo growth of MDA-MB435, but not MCF7 cells, despite similar levels of in vivo production, and angiostatin did not impair the in vivo growth of either cell line. These findings indicate heterogeneity in the therapeutic efficacy of angiostatic molecules delivered by viral vectors and suggest that gene therapy with IFN-alpha(1) and endostatin might be useful for treatment of breast cancer.

Effects of CD2 locus control region sequences on gene expression by retroviral and lentiviral vectors.

Locus control region (LCR) sequences are involved in the establishment of open chromosomal domains. To evaluate the possibility of exploiting the human CD2 LCR to regulate gene expression by Moloney murine leukemia virus (Mo-MLV)-based retroviral vectors in T cells, it was included in vectors carrying the enhanced green fluorescence protein (EGFP) reporter gene; then transduction in vitro of lymphoid and nonlymphoid cell lines was performed. Deletion of the viral enhancer in the Mo-MLV long terminal repeat was necessary to detect LCR activity in the context of these retroviral vectors. It was found that a full-length (2.1 kb), but not a truncated (1.0 kb), CD2 LCR retained the ability to modulate reporter gene expression by Mo-MLV-derived retroviral vectors, leading to a homogeneous, unimodal pattern of EGFP expression that remained unmodified in culture over time, specifically in T-cell lines; on the other hand, viral titer was strongly reduced compared with vectors not carrying the LCR. Lentiviral vectors containing the CD2 LCR could be generated at higher titers and were used to analyze its effects on gene expression in primary T cells. Subcutaneous implantation of genetically modified cells in immunodeficient mice showed that retroviral vectors carrying the CD2 LCR conferred an advantage in terms of transgene expression in vivo, compared with the parental vector, by preventing the down-modulation of EGFP expression. These findings suggest a potential application of this LCR to increase gene expression by retroviral and lentiviral vectors in T lymphocytes.

Block of a mitochondrial-mediated apoptotic pathway in Tax-expressing murine fibroblasts.

Although the viral transactivator Tax has been established as an essential effector of HTLV-I-mediated oncogenesis, its exact role(s) in the pathogenesis of HTLV-I-associated diseases, which include both a neurodegenerative pathology and leukemia/lymphoma, remains to be clarified. It was recently advanced that dysregulation of the apoptotic process can lead to pathophysiological changes which result in either degenerative diseases or cancer. As the apoptotic potential of Tax is still debated, we addressed this question by testing the susceptibility of Tax(+) and Tax(-) murine fibroblasts to apoptosis under conditions of growth factor withdrawal or treatment with TNFalpha, which trigger apoptosis through different pathways, i.e., mitochondrial and receptor-mediated pathways, respectively. Results showed that Tax-expressing cells are protected from apoptotic death induced by serum deprivation but are sensitive to TNFalpha-mediated apoptosis, suggesting that Tax expression has different effects on cell death, depending on the apoptotic stimulus used. Analysis of the mechanism(s) involved in the resistance to serum depletion-induced apoptosis indicated that Tax(+) cells do not undergo release of cytochrome c from the mitochondrial intermembrane space or redistribution of Bax from the cytosol to mitochondria, two phenomena critical to the mitochondrial apoptotic pathway.

Expression and functional properties of proteins encoded in the x-II ORF of HTLV-I.

With the aim of identifying viral proteins that contribute to the distinctive properties of HTLV-I biology and pathogenicity, several laboratories have investigated the coding potential of the X region of the genome, which includes five partially overlapping open reading frames (ORFs). We and others have shown that, in addition to the essential regulatory proteins Rex and Tax, a number of accessory proteins encoded in the X region can be produced by alternative splicing and multicistronic translation. One X region ORF, termed X-II, produces two protein isoforms named Tof/p30II and p13II, which are expressed from a doubly- and singly-spliced mRNA, respectively. Initial functional analyses demonstrated that Tof/p30II is a nucleolar/nuclear protein that possesses a region capable of binding to RNA, and p13II is a mitochondrial protein that alters the morphology and function of this organelle. Together with data from other laboratories demonstrating the production of antibodies and CTL against x-II ORF products in HTLV-I infected subjects and the requirement of this ORF for efficient viral replication in vivo, these findings suggest that further characterization of Tof/p30II and p13II will yield insight into remaining undefined aspects of HTLV-I pathogenicity and replication.

Effects of angiostatin gene transfer on functional properties and in vivo growth of Kaposi's sarcoma cells.

Gene transfer delivery of endogenous angiogenesis inhibitors such as angiostatin would circumvent problems associated with long-term administration of proteins. Kaposi's sarcoma (KS), a highly vascular neoplasm, is an excellent model for studying tumor angiogenesis and antiangiogenic agent efficacy. We investigated the effects of angiostatin gene transfer in in vitro and in vivo models of KS-induced neovascularization and tumor growth. A eukaryotic expression plasmid and a Moloney leukemia virus-based retroviral vector for expression of murine angiostatin were generated harboring the angiostatin cDNA with cleavable leader signals under the control of either the strong cytomegalovirus promoter/enhancer or the Moloney leukemia virus long terminal repeat. Angiostatin secretion was confirmed by radioimmunoprecipitation and Western blot analysis. Supernatants of angiostatin-transfected cells inhibited endothelial cell migration in vitro. Stable gene transfer of the angiostatin cDNA by retroviral vectors in KS-IMM cells resulted in sustained angiostatin expression and delayed tumor growth in nude mice, which was associated with reduced vascularization. These findings suggest that gene therapy with angiostatin might be useful for treatment of KS and possibly other highly angiogenic tumors.

Neopterin production in SCID mice injected with human peripheral blood mononuclear cells.

Intraperitoneal transfer of peripheral blood mononuclear cells (PBMC) from human EBV+ donors into severe combined immunodeficiency (SCID) mice is a suitable model for studying some aspects of lymphomagenesis and immune activation. Neopterin is a soluble immune marker which was found to be a useful indicator for immune activation processes in humans, e.g. to monitor immunological complications in allograft recipients or to predict prognosis in HIV-infected individuals. In contrast, this pteridine compound is normally synthesized in murine organism in only very low amounts. The measurement of neopterin concentrations in serum and urine should be feasible in SCID mice reconstituted with human PBMC. In this study, we examined the usability of this experimental model for monitoring human T cell activation by neopterin measurements. The production of neopterin by SCID mice after injection of freshly isolated human PBMC, purified B or T cells and cultured Epstein-Barr virus (EBV)+ lymphoblastoid cells (LCL) was determined. It was found that neopterin can be detected early after injecting SCID mice with PBMC, whereas injection of purified human T or B cells did not result in neopterin production. Highest neopterin levels were detected in mice treated with LCL cells when developing lymphoma. We discuss the possible sources of neopterin along this process and its usefulness in this model.

HPV-related neoplasias in HIV-infected individuals.

Human papillomavirus (HPV) infection of the lower genital tract is now considered the most important factor in the initiation of neoplasia. Human immunodeficiency virus (HIV) infection appears to alter the natural history of HPV-associated oncogenesis, but its impact on gynaecology has only recently been defined; the Centers for Disease Control (CDC) designated moderate and severe cervical dysplasia as a category B defining condition, and invasive cervical cancer as a category C defining condition of AIDS in 1993. Anal HPV infection and anal squamous intra-epithelial lesions have been found to be highly prevalent among HIV-positive homosexual men, and recent preliminary data suggest a relatively high prevalence among HIV-positive women as well. Moreover, HPV infection and associated lesions are also observed in body sites other than the anogenital area, particularly the skin and the oral cavity.

Lack of association between androgen receptor CAG polymorphism and familial breast/ovarian cancer.

The human androgen receptor (AR) gene contains a highly polymorphic CAG repeat in exon 1 that is inversely correlated with AR transcriptional activity in vitro. Several studies have shown that fewer CAG repeats are associated with an increased risk as well as more aggressive forms of prostate cancer. More recently, AR allele length was also inversely correlated with the histological grade of breast cancer, but no association was found between the AR-CAG polymorphism and the risk of either breast or ovary cancer. On the contrary, it was proposed that a longer CAG repeat sequence might be associated with an increased risk of breast cancer in BRCA1 mutation carriers, thus suggesting a different role of the AR-CAG polymorphism in sporadic and inherited breast cancers. With the intent of better understanding the role of the AR-CAG polymorphism as a cancer risk modifier, we defined the AR genotype of 151 patients (101 with breast and 50 with ovary cancer) belonging to high-risk breast/ovary cancer families. No difference in CAG repeat length was found between either breast and ovary cancer patients or age at diagnosis of both tumors. These results were also confirmed in a sub-group of 47 breast cancer cases, that either carried a BRCA gene mutation (11 cases) or were identified by very stringent operational criteria as hereditary breast cancers. Even though a substantially larger sample size would be required to reach conclusive evidence, our findings suggest that the AR-CAG polymorphism does not act as a modifier of tumor onset or tumor phenotype in breast/ovarian cancer families.

P27kip1 expression is associated with tumor response to preoperative chemoradiotherapy in rectal cancer.

BACKGROUND: Our aim was to ascertain whether or not the response to preoperative chemoradiotherapy for rectal cancer is associated with p27kip1 and p53 protein expression. METHODS: Thirty-eight patients (27 male, 11 female) with a mean age of 59 years (age range 33-87) and stage II-III rectal cancer received preoperative chemoradiotherapy (45-50.4 Gy; 5-FU 350 mg/m2/day and leucovorin 10 mg/m2/day). Thirty-one underwent low anterior resection; seven underwent abdominoperineal excision. Endoscopic tumor biopsies, performed before adjuvant therapy, were evaluated for: histologic type, tumor differentiation, mitotic index, and p27kip1 and p53 protein expression which were immunohistochemically determined. p53 expression was graded as: a) absent or present in < or =10% of tumor cells; b) present in 11-25%; c) present in 26-75%; and d) present in >75% of tumor cells. p27kip1 expression was assessed using both light microscopy (percent of stained cells x10 HPF) and cytometry with an image analysis workstation. Tumor response, ascertained with histology, was classified using a scale from 0 (no response) to 6 (complete pathologic response). RESULTS: The mitotic index for the endoscopic biopsies was low in 14 cases, moderate in 17 cases, and high in 7 cases. p53 protein expression was found in 21 (a), 3 (b), 3 (c), and 11 (d) cases. The mean percentage of cells expressing the p27kip1 protein was 34 (range 0-77.14%). A close correlation was found between cytometric and light microscopy findings for p27kip1 (r2 = 0.92, P = .0001). Tumor differentiation was good in 5 cases, poor in 2 cases, and moderate in the remaining 31 cases. While the response to adjuvant therapy was good/complete in 25 (65.78%) cases, it was absent/poor in 13 (34.21%) cases. Univariate analysis associated type of adjuvant therapy (chemoradiotherapy, P = .0428) and p27kip1 protein lower expression (P = .0148) with a poor response to adjuvant treatment. Stepwise linear regression found overexpression of p53 and p27kip1 and young age to be independent variables that were linked to a good response to adjuvant therapy. CONCLUSIONS: Lack of p27kip1 and p53 protein expression in rectal cancer is associated with a poor response to preoperative adjuvant therapy.

Acquired immunodeficiency syndrome-related Kaposi's sarcoma regression after highly active antiretroviral therapy: biologic correlates of clinical outcome.

BACKGROUND: Kaposi's sarcoma (KS) is the most common cancer seen in subjects with acquired immunodeficiency syndrome (AIDS). KS etiology and pathogenesis are still ill defined, and no definite improvement in survival has been obtained with current chemotherapeutic regimens. This open prospective study was aimed at evaluating the clinical response of AIDS-related KS to highly active antiretroviral therapy (HAART), a combination of protease and reverse transcriptase inhibitors, as well as the relationship between clinical response, human immunodeficiency virus type 1 (HIV-1) burden, and antibody titer against human herpesvirus 8 (HHV8) proteins. PATIENTS AND METHODS: Fourteen KS patients were studied; 12 were in the poor-risk group. At given intervals, the patients underwent clinical examination, and their CD4(+) cell counts, plasma HIV-1 RNA levels, and antibody titers to lytic-phase ORF65 and latent-phase HHV8 proteins were determined. RESULTS: When last seen, the overall clinical response rate was 86% (median follow-up, 22 months); 10 complete and two partial responses were achieved, and two patients showed disease progression. All patients with complete or partial response showed a consistent decrease in HIV-1 RNA levels, with a corresponding increase in CD4(+) cell counts; HIV-1 RNA levels in the two progressors remained persistently high, despite a change in HAART. HHV8 ORF65 antibody titers were generally higher in patients with extensive skin or mucosal/visceral involvement versus patients with limited disease; no differences in latent-phase HHV8 antibody titers were observed in relation to tumor burden. CONCLUSION: The findings indicate that antiretroviral therapy with protease inhibitors is effective for AIDS-related KS; the clinical response was correlated with a decrease in plasma HIV-1 RNA levels and an increase in CD4(+) lymphocytes, whereas antibody levels to the lytic-phase HHV8 protein were influenced by the extent of tumor involvement.

Polymorphisms in the CCR5 promoter region influence disease progression in perinatally human immunodeficiency virus type 1-infected children.

The effect of CC-chemokine receptor 5 (CCR5) promoter polymorphisms on the natural history of human immunodeficiency virus (HIV) disease was studied in 73 HIV-1-infected children. The CCR5(59338-59537) promoter haplotype, CCR5-59029A/G polymorphism, and CCR5Delta32 and CCR2-64I alterations were investigated. After exclusion of carriers of CCR5Delta32 or CCR2-64I, Kaplan-Meier analysis disclosed that children with the P1/P1(59353C,59356C,59402A) genotype progressed faster to disease than did children with other haplotypes (P=.016). When CCR2-64I carriers were included, this effect had borderline significance (P=.065) and was lost when CCR5Delta32 carriers were also considered (P=.387). The P1/P1 effect was strongest early after infection, when progression to disease was mainly associated with CCR5 coreceptor-using viruses. These results indicate that the P1/P1 genotype is predictive of rapid progression in HIV-1-infected children lacking CCR5Delta32 or CCR5-64I alleles. The observation of a linkage disequilibrium between P1 and 59029A might explain the previously reported association between 59029A homozygosity and rapid disease progression.

Human immunodeficiency virus type 1 modulates telomerase activity in peripheral blood lymphocytes.

The effect of human immunodeficiency virus type 1 (HIV-1) on telomerase activity in peripheral blood lymphocytes (PBL) was examined. Telomerase is an enzyme that is involved in mechanisms that control cell life span and replicative potential. HIV-1 reduced telomerase activity in in vitro-infected PBL and impaired enzyme activation upon cell stimulation. Telomerase activity was significantly lower in PBL from 23 HIV-1-infected patients than in PBL from healthy donors and significantly increased during highly active antiretroviral therapy (HAART) in 10 patients who had both a virological and an immunological response and in 5 and 8 patients with a virological or an immunological response, respectively. Further analyses of fractionated cells revealed that telomerase activity increased mainly in CD4(+) lymphocytes. Overall, these findings demonstrate that HIV-1 infection down-modulates telomerase activity and suggest that both the HIV-1 decline and immunorestoration in response to HAART contribute to increased telomerase activity in CD4(+) lymphocytes.