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Biomedical subjects

Yasuo Saijo

Publications and source records attributed to Yasuo Saijo.

At least 19 recordsLinked to original sources
PubMed2006

Prospective phase II study of gefitinib for chemotherapy-naive patients with advanced non-small-cell lung cancer with epidermal growth factor receptor gene mutations.

PURPOSE: This study was undertaken to investigate the efficacy and the feasibility of gefitinib for chemotherapy-naïve patients with advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. PATIENTS AND METHODS: The EGFR gene status in various tumor samples obtained from chemotherapy-naïve advanced NSCLC patients was examined by DNA sequencing of EGFR exons 18 to 23. Patients harboring EGFR mutations received gefitinib (250 mg/d) alone. The response rate, progression-free survival (PFS), and toxicity profile were assessed prospectively. RESULTS: Between June 2004 and October 2005, 75 patients were examined for the EGFR status, and 25 patients (33%) harbored EGFR mutations. EGFR mutations were significantly frequent in females (P < .01) and never or light smokers (P < .001). Sixteen patients with EGFR mutations were enrolled onto the study. The overall response rate in these patients was 75% (95% CI, 54% to 96%), and the disease control rate was 88% (95% CI, 71% to 100%). The median PFS time of these patients was 9.7 months (95% CI, 7.4 to 9.9 months). No life-threatening toxicity was observed. CONCLUSION: Treatment with gefitinib alone for chemotherapy-naïve NSCLC patients with EGFR mutations could achieve a high efficacy with acceptable toxicity. To assess the proper timing of gefitinib in such patients, a subsequent randomized trial comparing gefitinib with standard chemotherapy is warranted.

Adult↗
PubMed2006

Multicenter phase I study of repeated intratumoral delivery of adenoviral p53 in patients with advanced non-small-cell lung cancer.

PURPOSE: To determine the feasibility, safety, humoral immune response, and biologic activity of multiple intratumoral injections of Ad5CMV-p53, and to characterize the pharmacokinetics of Ad5CMV-p53 in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Fifteen patients with histologically confirmed NSCLC and p53 mutations were enrolled onto this phase I trial. Nine patients received escalating dose levels of Ad5CMV-p53 (1 x 10(9) to 1 x 10(11) plaque-forming units) as monotherapy once every 4 weeks. Six patients were treated on a 28-day schedule with Ad5CMV-p53 in combination with intravenous administration of cisplatin (80 mg/m2). Patients were monitored for toxicity, vector distribution, antibody formation, and tumor response. RESULTS: Fifteen patients received a total of 63 intratumoral injections of Ad5CMV-p53 without dose-limiting toxicity. The most common treatment-related toxicity was a transient fever. Specific p53 transgene expression was detected using reverse-transcriptase polymerase chain reaction in biopsied tumor tissues throughout the period of treatment despite of the presence of neutralizing antiadenovirus antibody. Distribution studies revealed that the vector was detected in the gargle and plasma, but rarely in the urine. Thirteen of 15 patients were assessable for efficacy; one patient had a partial response (squamous cell carcinoma at the carina), 10 patients had stable disease, with three lasting at least 9 months, and two patients had progressive disease. CONCLUSION: Multiple courses of intratumoral Ad5CMV-p53 injection alone or in combination with intravenous administration of cisplatin were feasible and well tolerated in advanced NSCLC patients, and appeared to provide clinical benefit.

Aged↗
PubMed2006

A phase II study of weekly paclitaxel combined with carboplatin for elderly patients with advanced non-small cell lung cancer.

We conducted this phase II study to explore the efficacy and safety of weekly paclitaxel combined with carboplatin in elderly patients with advanced non-small cell lung cancer (NSCLC). Elderly patients (> or = 70 years old) of stage IIIB, IV, or recurrent NSCLC with PS 0 or 1 were enrolled. Patients received paclitaxel at a dose of 70 mg/m2 on Days 1, 8, 15, and carboplatin at the target dose of the area under the curve (AUC) of six on Day 1 every 28 days for at least two cycles. Forty-two patients were enrolled and 40 patients were treated with a median of three cycles (range, 1-5). The overall response rate (ORR) was 45% (95% confidence interval, 30-60%). The median survival time (MST) was 14 months and the 1-year survival rate was 62%. Twenty-eight patients (70%) had grade 3/4 neutropenia and two patients (5%) experienced grade 3 febrile neutropenia. Non-hematological toxicities were generally mild to moderate and grade 3 peripheral neuropathy was seen in one patient (3%). There was one treatment-related death by infection due to neutropenia. Weekly paclitaxel and carboplatin combination chemotherapy was an effective and safe regimen in elderly patients with advanced NSCLC. A randomized trial comparing this treatment with the conventional tri-weekly regimen of paclitaxel and carboplatin is warranted.

Aged↗
PubMed2006

Dendritic cells modified to express fractalkine/CX3CL1 in the treatment of preexisting tumors.

Fractalkine (CX3CL1) is a unique membrane-bound CX3C chemokine that serves as a potent chemoattractant for lymphocytes. The hypothesis of this study is that dendritic cells (DC) genetically modified ex vivo to overexpress fractalkine would enhance the T cell-mediated cellular immune response with a consequent induction of anti-tumor immunity to suppress tumor growth. To prove this hypothesis, established tumors of different mouse cancer cells (B16-F10 melanoma, H-2b, and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of bone marrow-derived DC that had been modified in vitro with an RGD fiber-mutant adenovirus vector expressing mouse fractalkine (Ad-FKN). In both tumor models tested, treatment of tumor-bearing mice with Ad-FKN-transduced DC gave rise to a significant suppression of tumor growth along with survival advantages in the treated mice. Immunohistochemical analysis of tumors treated with direct injection of Ad-FKN-transduced DC demonstrated that the treatment prompted CD8+ T cells and CD4+ T cells to accumulate in the tumor milieu, leading to activation of immune-relevant processes. Consistent with the finding, the intratumoral administration of Ad-FKN-transduced DC evoked tumor-specific cytotoxic T lymphocytes, which ensued from in vivo priming of Th1 immune responses in the treated host. In addition, the anti-tumor effect provided by intratumoral injection of Ad-FKN-transduced DC was completely abrogated in CD4+ T cell-deficient mice as well as in CD8+ T cell-deficient mice. These results support the concept that genetic modification of DC with a recombinant fractalkine adenovirus vector may be a useful strategy for cancer immunotherapy protocols.

Adenoviridae↗
PubMed2006

[A case of pulmonary Langerhans cell histiocytosis discovered by CT mass screening and followed by bronchoalveolar lavage].

A 42-year-old woman who had a cigarette index of 420 had many cavitary lesions predominantly in the upper areas of both lungs. The lesions were detected on a health examination using CT. Analysis with bronchofiberscopy showed increased CD1a positive cells in bronchoalveolar fluid (BALF). Histological examination by video-associated lung biopsy demonstrated that both S-100 and vimentin-positive cells were present in the peribronchial fibrotic lesions. From these data, this disease was diagnosed as pulmonary Langerhans cell histiocytosis (PLCH). Three months after the cessation of smoking, the cavity lesions disappeared. As the image findings improved, CD1a positive cells in BALF decreased (4.9% --> 1.8%) and the CD4/CD8 ratio in BALF increased (1.66 --> 6.16). So far, there is no report describing the time course of both CD1a positive cells and CD4/CD8 ratio in BALF after cessation of smoking in PLCH. These findings attract our interest on the PLCH.

Adult↗
PubMed2005

Infiltration of COX-2-expressing macrophages is a prerequisite for IL-1 beta-induced neovascularization and tumor growth.

Inflammatory angiogenesis is a critical process in tumor progression and other diseases. The inflammatory cytokine IL-1beta promotes angiogenesis, tumor growth, and metastasis, but its mechanisms remain unclear. We examined the association between IL-1beta-induced angiogenesis and cell inflammation. IL-1beta induced neovascularization in the mouse cornea at rates comparable to those of VEGF. Neutrophil infiltration occurred on day 2. Macrophage infiltration occurred on days 4 and 6. The anti-Gr-1 Ab-induced depletion of infiltrating neutrophils did not affect IL-1beta- or VEGF-induced angiogenesis. The former was reduced in monocyte chemoattractant protein-1-deficient (MCP-1(-/-)) mice compared with wild-type mice. After day 4, clodronate liposomes, which kill macrophages, reduced IL-1beta-induced angiogenesis and partially inhibited VEGF-induced angiogenesis. Infiltrating macrophages near the IL-1beta-induced neovasculature were COX-2 positive. Lewis lung carcinoma cells expressing IL-1beta (LLC/IL-1beta) developed neovasculature with macrophage infiltration and enhanced tumor growth in wild-type but not MCP-1(-/-) mice. A COX-2 inhibitor reduced tumor growth, angiogenesis, and macrophage infiltration in LLC/IL-1beta. Thus, macrophage involvement might be a prerequisite for IL-1beta-induced neovascularization and tumor progression.

Animals↗
PubMed2005

Vaccination of dendritic cells loaded with interleukin-12-secreting cancer cells augments in vivo antitumor immunity: characteristics of syngeneic and allogeneic antigen-presenting cell cancer hybrid cells.

Cancer immunotherapy by fusion of antigen-presenting cells and tumor cells has been shown to induce potent antitumor immunity. In this study, we characterized syngeneic and allogeneic, murine macrophage/dendritic cell (DC)-cancer fusion cells for the antitumor effects. The results showed the superiority of allogeneic cells as fusion partners in both types of antigen-presenting cells in an in vivo immunotherapy model. A potent induction of tumor-specific CTLs was observed in these immunized conditions. In addition, the immunization with DC-cancer fusion cells was better than that with macrophage-cancer fusion cells. Both syngeneic and allogeneic DC-cancer fusion cells induced higher levels of IFN-gamma production than macrophage-cancer fusion cells. Interestingly, allogeneic DC-cancer fusion cells were superior in that they efficiently induced Th1-type cytokines but not the Th2-type cytokines interleukin (IL)-10 and IL-4, whereas syngeneic DC-cancer fusion cells were powerful inducers of both Th1 and Th2 cytokines. These results suggest that allogeneic DCs are suitable as fusion cells in cancer immunotherapy. To further enhance the antitumor immunity in the clinical setting, we prepared DCs fused with IL-12 gene-transferred cancer cells and thus generated IL-12-secreting DC-cancer fusion cells. Immunization with these gene-modified DC-cancer fusion cells was able to elicit a markedly enhanced antitumor effect in the in vivo therapeutic model. This novel IL-12-producing fusion cell vaccine might be one promising intervention for future cancer immunotherapy.

Animals↗
PubMed2005

Antitumor immune response by CX3CL1 fractalkine gene transfer depends on both NK and T cells.

The CX3C chemokine fractalkine (CX3CL1) exists as both a membrane-bound form promoting firm cell-cell adhesion and a soluble form chemoattracting leukocytes expressing its receptor CX3CR1. When adenoviral vector expressing mouse fractalkine (AdFKN) was transduced to the tumor cells, fractalkine was expressed as both membrane-bound form on the tumor cells and soluble form in the supernatant in vitro. Intratumoral injection of AdFKN (1 x 10(9)PFU/tumor) into C26 and B16F10 tumors resulted in marked reduction of tumor growth compared to control (C26: 86.5%, p<0.001; B16F10: 85.5%, p<0.001). Histological examination of tumor tissues revealed abundant infiltration of NK cells, dendritic cells, and CD8(+) T lymphocytes 3 and/or 6 days after treatment with AdFKN. Splenocytes from mice treated by AdFKN developed tumor-specific cytotoxic T cells, and thereby protected from rechallenging with parental tumor cells. Antitumor effects by AdFKN were completely abrogated in both NK cell-depleted mice and CD8(-/-) mice, and partially blocked in CD4(-/-) mice. These data indicated that fractalkine mediates antitumor effects by both NK cell-dependent and T cell-dependent mechanisms. This study suggests that fractalkine can be a suitable candidate for immunogene therapy of cancer because fractalkine induces both innate and adaptive immunity.

Animals↗
PubMed2005

Involvement of fractalkine/CX3CL1 expression by dendritic cells in the enhancement of host immunity against Legionella pneumophila.

Legionnaires' disease is clinically manifested as severe pneumonia caused by Legionella pneumophila. However, the dendritic cell (DC)-centered immunological framework of the host defense against L. pneumophila has not been fully delineated. For this study, we focused on a potent chemoattractant for lymphocytes, fractalkine/CX3CL1, and observed that the fractalkine expression of DCs was somewhat up-regulated when they encountered L. pneumophila. We therefore hypothesized that fractalkine expressed by Legionella-capturing DCs is involved in the induction of T-cell-mediated immune responses against Legionella, which would be enhanced by a genetic modulation of DCs to overexpress fractalkine. In vivo immunization-challenge experiments demonstrated that DCs modified with a recombinant adenovirus vector to overexpress fractalkine (AdFKN) and pulsed with heat-killed Legionella protected immunized mice from a lethal Legionella infection and that the generation of in vivo protective immunity depended on the host lymphocyte subsets, including CD4(+) T cells, CD8(+) T cells, and B cells. Consistent with this, immunization with AdFKN/Legionella/DC induced significantly higher levels of serum anti-Legionella antibodies of several isotypes than those induced by control immunizations. Further analysis of spleen cells from the immunized mice indicated that the AdFKN/Legionella/DC immunization elicited Th1-dominated immune responses to L. pneumophila. These observations suggest that fractalkine may play an important role in the DC-mediated host defense against intracellular pathogens such as L. pneumophila.

Animals↗
PubMed2004

Gene therapy with secretory leukoprotease inhibitor promoter-controlled replication-competent adenovirus for non-small cell lung cancer.

Secretory leukoprotease inhibitor (SLPI) is highly expressed in almost all non-small cell lung cancers (NSCLCs), but not in the majority of other tumor types. In an attempt to create a specific gene therapy for NSCLC, we constructed AdSLPI.E1AdB, an adenovirus vector with a double expression cassette consisting of E1A driven by the SLPI promoter gene followed by E1B-19K under the control of the cytomegalovirus (CMV) promoter that can selectively replicate only in NSCLC cells. Infection with AdSLPI.E1AdB yielded E1A protein expression and adenovirus replication resulting in a >100-fold increase of the virus titers only in SLPI-producing NSCLC cells (A549, H358, and HS24 cells). In contrast, neither E1A protein nor replication was detected in non-SLPI-producing HepG2 cells. Treatment with AdSLPI.E1AdB significantly inhibited the proliferation of NSCLC cells in vitro in a dose-dependent manner, whereas the cell growth of HepG2 or normal human bronchial epithelial cells was not affected by AdSLPI.E1AdB infection. Direct injection of AdSLPI.E1AdB into A549 and H358 tumors in nude mice resulted in a marked reduction in tumor growth compared with controls (A549, 57%, P < 0.02; H358, 67%, P < 0.03). Histological examination revealed the replication of AdSLPI.E1AdB and strong induction of necrosis and apoptosis. In addition, we evaluated the combination of AdSLPI.E1AdB and AdCMV.NK4 encoding NK4 protein, which has strong antiangiogenic activity. E1A expressed by AdSLPI.E1AdB trans-acts on the replication of AdCMV.NK4 and thus increases the expression of NK4. Injection of these two vectors into H358 tumors resulted in a more striking reduction of tumor growth compared with single injection of each vector. These results suggest that AdSLPI.E1AdB could provide a selective therapeutic modality for NSCLC and that the combination of AdSLPI.E1AdB and AdCMV.NK4 may be a more effective gene therapy for NSCLC.

Adenoviridae↗
PubMed2004

Adenovirus vector-mediated in vivo gene transfer of OX40 ligand to tumor cells enhances antitumor immunity of tumor-bearing hosts.

OX40 ligand (OX40L), the ligand for OX40 on activated CD4+ T cells, has adjuvant properties for establishing effective T-cell immunity, a potent effector arm of the immune system against cancer. The hypothesis of this study is that in vivo genetic engineering of tumor cells to express OX40L will stimulate tumor-specific T cells by the OX40L-OX40 engagement, leading to an induction of systemic antitumor immunity. To investigate this hypothesis, s.c. established tumors of three different mouse cancer cells (B16 melanoma, H-2b; Lewis lung carcinoma, H-2b; and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of a recombinant adenovirus vector expressing mouse OX40L (AdOX40L). In all tumor models tested, treatment of tumor-bearing mice with AdOX40L induced a significant suppression of tumor growth along with survival advantages in the treated mice. The in vivo AdOX40L modification of tumors evoked tumor-specific cytotoxic T lymphocytes in the treated host correlated with in vivo priming of T helper 1 immune responses in a tumor-specific manner. Consistent with the finding, the antitumor effect provided by intratumoral injection of AdOX40L was completely abrogated in a CD4+ T cell-deficient or CD8+ T cell-deficient condition. In addition, ex vivo AdOX40L-transduced B16 cells also elicited B16-specific cytotoxic T lymphocyte responses, and significantly suppressed the B16 tumor growth in the immunization-challenge experiment. All of these results support the concept that genetic modification of tumor cells with a recombinant OX40L adenovirus vector may be of benefit in cancer immunotherapy protocols.

Adenoviridae↗
PubMed2003

N-terminal deletion augments the cell-death-inducing activity of BAX in adenoviral gene delivery to nonsmall cell lung cancers.

Therapeutic modalities that overcome the antiapoptotic function of Bcl-2 that is often overexpressed in cancer cells are expected to be a novel strategy for cancer treatment. We previously reported that the leukemic cell death induced by an N-terminally truncated Bax (deltaN Bax: corresponding to amino acid 112-192 of full-length Bax) was not blocked by Bcl-2 or Bcl-x(L) owing to the lack of the BH3 domain needed to interact with the antiapoptotic Bcl-2 family molecules. In this study, we used the Cre-loxP system that allowed us to propagate adenoviruses expressing deltaN Bax, and investigated the effects of the deltaN Bax gene transfer into A549 and NCI-H1299 nonsmall cell lung cancer cell lines. deltaN Bax showed more cell-death-inducing activity in both cells than did the full-length Bax in vitro. It was found that the deltaN Bax-induced cell death was not inhibited by the pan-caspase inhibitor z-VAD-fmk, suggesting that deltaN Bax induces cell death through a caspase-independent mechanism. Intratumoral injection of adenoviruses expressing deltaN Bax into A549 tumors in Balb/c nude mice showed a significantly stronger suppression of tumor growth (74%) than full-length Bax (25%) compared to the control. Our results suggest that deltaN Bax may provide a better alternative than currently used cytotoxic genes in cancer gene therapy trials.

Adenoviridae↗
PubMed2003

Severe acute interstitial pneumonia and gefitinib.

Gefitinib is an oral selective inhibitor of the epidermal growth factor receptor tyrosine kinase that is an effective treatment for patients with advanced non-small cell lung cancer who do not respond to platinum-based chemotherapy. We assessed four patients who had non-small cell lung cancer causing severe acute interstitial pneumonia in association with gefitinib. Although two patients recovered after treatment with steroids, the other two died from progressive respiratory dysfunction. On the basis of autopsies and bilateral distribution of diffuse ground-glass opacities in chest CTs, we diagnosed diffuse alveolar damage, which was consistent with acute interstitial pneumonia. Patients with interstitial pneumonia also had other pulmonary disorders such as previous thoracic irradiation and poor performance status. Physicians should be aware of the alveolar damage induced by gefitinib, especially for patients with these characteristic features.

Adult↗
PubMed2003

Identification of a CTL-directed epitope encoded by an intron of the putative tumor suppressor gene Testin of the common fragile site 7G region: a peptide vaccine candidate for HLA-B52+ and HLA-62+ cancer patients.

Although cytotoxic T lymphocyte (CTL)-directed epitopes binding to human histocompatibility leukocyte antigen (HLA)-A molecules have been well characterized, those binding to HLA-B molecules have not, largely due to their large diversity. In this study we report a unique cancer antigen gene, tentatively named Testin-related gene (TRG), which encodes CTL-directed epitopes on the HLA-B52 molecules most frequently expressed in Asians. TRG is located in an intron of the putative tumor suppressor gene Testin in the common fragile site 7G region at 7q31.2. TRG mRNA was expressed in the majority of cancer cells and cancer tissue tested, whereas it was scarcely expressed in the majority of normal tissues, and only low-level expression of TRG was detected in the heart, liver, and pancreas. One TRG peptide had the ability to induce HLA-B52-restricted CTL cytotoxic to TRG+ tumor cells in peripheral blood mononuclear cells (PBMC) of epithelial cancer patients. This peptide also induced HLA-B62-restricted and tumor-reactive CTL in PBMC of cancer patients. Therefore, this TRG-derived peptide might be appropriate for use in peptide-based immunotherapy for relatively large numbers of cancer patients throughout the world, given that 34% of Japanese, 27% of Chinese, and 13% of Caucasians express either HLA-B52 or HLA-B62 molecules

Cancer Vaccines↗
PubMed2003

Multifunctional interleukin-1beta promotes metastasis of human lung cancer cells in SCID mice via enhanced expression of adhesion-, invasion- and angiogenesis-related molecules.

We examined whether interleukin-1 (IL-1), a multifunctional proinflammatory cytokine, progresses or regresses metastasis of lung cancer. Exogenous IL-1beta enhanced expression of various cytokines (IL-6, IL-8, and vascular endothelial growth factor (VEGF)) and intracellular adhesion molecule-1 (ICAM-1) by A549, PC14, RERF-LC-AI, and SBC-3 cells expressing IL-1 receptors. A549 cells transduced with human IL-1beta-gene with the growth-hormone signaling-peptide sequence (A549/IL-1beta) secreted a large amount of IL-1beta protein. Overexpression of IL-1beta resulted in augmentation of expression of the cytokines, ICAM-1, and matrix metalloproteinase-2 (MMP-2). A549/IL-1beta cells intravenously inoculated into severe combined immunodeficiency (SCID) mice distributed to the lung more efficiently and developed lung metastasis much more rapidly than did control A549 cells. Treatment of SCID mice with anti-IL-1beta antibody inhibited formation of lung metastasis by A549/IL-1beta cells. Moreover, A549/IL-1beta cells inoculated in the subcutis grew more rapidly, without necrosis, than did control A549 cells, which produced smaller tumors with central necrosis, suggesting involvement of angiogenesis in addition to enhanced binding in the high metastatic potential of A549/IL-1beta cells. Histological analyses showed that more host-cell infiltration, fewer apoptotic cells, more vascularization, and higher MMP activity were observed in tumors derived from A549/IL-1beta cells, compared with tumors derived from control A549 cells. These findings suggest that IL-1beta facilitates metastasis of lung cancer via promoting multiple events, including adhesion, invasion and angiogenesis.

Angiogenesis Inducing Agents↗
PubMed2002

Proinflammatory cytokine IL-1 beta promotes tumor growth of Lewis lung carcinoma by induction of angiogenic factors: in vivo analysis of tumor-stromal interaction.

Inflammatory conditions are associated with tumor development. IL-1beta is a multifunctional and proinflammatory cytokine that affects nearly all types of cells. To investigate the role of IL-1beta in tumor growth in vivo, we transduced the retroviral vector coding human IL-1beta gene into mouse Lewis lung carcinoma (LLC) cells and subsequently inoculated the transformant (LLC/IL-1beta) to syngeneic C57BL/6 mice. Tumors derived from LLC/IL-1beta grew faster (240%, day 18, vs null-vector control LLC/neo; p < 0.01) and showed more abundant vasculature (250%, vs LLC/neo; p < 0.05), whereas LLC/IL-1beta cells, LLC/neo cells, and wild-type LLC cells did not show any significant difference in the growth rate in vitro. As compared with LLC/neo cells, LLC/IL-1beta cells secreted 2-fold the amount of vascular endothelial growth factor and >10-fold the amount of macrophage-inflammatory protein-2 (CXCL2), one of whose main functions is angiogenesis. Although LLC/IL-1beta itself did not secrete hepatocyte growth factor (HGF), the tumor derived from LLC/IL-1beta cells also contained a >4-fold higher concentration of HGF, another angiogenic factor. In situ hybridization of HGF mRNA in LLC/IL-1beta tumor sections demonstrated that stromal fibroblasts and infiltrating cells overexpressed HGF mRNA. Moreover, when cultured in the presence of HGF in vitro, LLC/IL-1beta cells secreted even larger amounts of vascular endothelial growth factor and macrophage-inflammatory protein-2. The antiangiogenic agent TNP-470 and anti-CXCR2 Ab inhibited the tumor growth of LLC/IL-1beta cells in vivo. These results indicated that secreting IL-1beta into the tumor milieu induces several angiogenic factors from tumor and stromal cells and thus promotes tumor growth through hyperneovascularization.

Angiogenesis Inducing Agents↗
PubMed2002

Gene transfer of thromboxane A(2) synthase and prostaglandin I(2) synthase antithetically altered tumor angiogenesis and tumor growth.

Cyclooxygenase, involved in tumor growth and angiogenesis, converts arachidonic acid to prostaglandin (PG)H(2), which is immediately converted to bioactive prostanoids including PGE(2), PGD(2), thromboxane (TX)A(2) and PGI(2). To test the hypothesis that changes in the prostanoid profile alter cancer growth, we transduced the retroviral vectors carrying TXA(2) synthase cDNA or PGI(2) synthase cDNA to colon-26 adenocarcinoma cells and subsequently inoculated each transformant to syngeneic BALB/c mice. Tumors derived from TXA(2) synthase transformants grew faster (280%, day 8, versus null-vector control; P < 0.05) and showed more abundant vasculature (204%, versus null-vector control; P < 0.01), whereas tumors from PGI(2) synthase transformants presented opposite effects. These effects by the transgenes were reversed by administration of specific inhibitors. These results suggest that the profile of downstream metabolites of cyclooxygenase in cancer cells can be a determinant for tumor development.

Adenocarcinoma↗