Biomedical subjects

G Fontanini

Publications and source records attributed to G Fontanini.

At least 19 recordsLinked to original sources

PubMed2006

Telomerase activity and hTERT mRNA expression in glial tumors.

Human telomerase is a structurally complex ribonucleoprotein that is responsible for the maintenance of telomeric DNA at the ends of the chromosomes. The enzyme is proposed as having an important role in cell immortalization and oncogenesis. A limited number of studies have been performed on the telomerase system in brain tumors, and these studies are somewhat conflicting. The relative ineffectiveness of current therapies for malignant gliomas led to the need for novel targets for more promising approaches. In order to clarify the prognostic significance of telomerase expression in gliomas and to speculate on therapeutic implications, we examined telomerase activity by the telomeric repeat amplification protocol (TRAP) assay in 42 gliomas, (32 multiform glioblastomas, 4 anaplastic astrocytomas, 4 differentiated astrocytomas, 1 oligoastrocytoma and 1 oligosarcoma). Telomerase messenger expression (hTERT mRNA) was evaluated by reverse transcription-PCR analysis in the same group of tumors. High telomerase activity was detected in 21/42 gliomas (50%). The levels of telomerase in terms of its messenger level expression overlapped the activity; in fact, a significant association between telomerase activity and hTERT mRNA expression was found (chi2 test; p<0.0001). At univariate analysis, advanced age as well as high telomerase activity and hTERT mRNA levels were seen to be significant predictors of worse prognosis regarding both overall survival (p=0.007, p=0.007, p=0.04, respectively) and disease-free interval (p=0.008, p=0.008, p=0.04, respectively). All these variables maintained a significant independent prognostic role in multivariate analysis. Telomerase may represent an indicator of progression and poor prognosis in this type of cancer, with interesting therapeutic implications.

Aged↗

PubMed2006

Thymomas: clinical-pathological correlations.

AIM: Since World Health Organization (WHO) histologic typing of tumors of the thymus publication in 1999 only a few studies correlated this classification with the clinical features of the patients. We present the results of a retrospective analysis on patients, operated on for a thymoma, whose specimens were available, to compare the WHO thymoma histologic classification to the clinical behavior of the tumors. METHODS: The specimens of 69 patients, who underwent surgical treatment between 1983 and 1998, were analyzed, comparing the clinical features of the patients and the hystological typing of the neoplasm, according to the WHO classification. A survival analysis of clinical and pathological prognostic factors was carried out. RESULTS: The incidence of thymus-related syndrome was related to the histological subtype and increases progressively from A to B3, while in C subtype the incidence was nihl. With a mean follow-up of 108 months (range 54-239 months), we experienced 6 intrathoracic recurrencies, 3 of those were intrapleuric and 3 mediastinal. At the last follow-up, 52 patients were alive; 1 with disease. Five deaths were related to the tumor (2 mediastinal and 3 intrapleuric relapses). Actuarial five-year and ten-year survival was 95% and 88.9%. Because of the absence of deaths related to thymomas in most samples it was not possible to perform a comparison among different histological types and different clinical stages. CONCLUSIONS: The WHO histologic classification seems to correlate with the incidence of thymus related syndromes and the clinical stage of Masaoka. Despite the higher incidence of recurrences in type B3 and C thymoma the WHO classification did not prove to be a prognostic factor.

Adult↗

PubMed2005

Prognostic significance of osteopontin expression in early-stage non-small-cell lung cancer.

Osteopontin (OPN) is a multifunctional protein, which has recently been shown to be linked to tumorigenesis, progression and metastasis in different malignancies. Since non-small-cell lung cancer (NSCLC)'s prognosis remains bad, with few predictors of outcome, the purpose of this study was to evaluate if OPN might be involved in NSCLC's biology and therefore represent a prognostic marker and a target for new therapeutic trials. Immunohistochemistry was used to detect OPN expression, evaluated as percentage of neoplastic cells with cytoplasmic immunoreactivity, in a wide cohort of patients with stage I NSCLC (136 cases). The median value of this series (20% of positive cells) was used as the cutoff value to distinguish tumours with low (<20%) from tumours with high (> or =20%) OPN expression. A statistically significant correlation between high levels of OPN and shorter overall (P = 0.034) and disease-free (P = 0.011) survival in our patients was shown. Our results support the hypothesis that high OPN expression is a significantly unfavourable prognostic factor for the survival of patients with stage I NSCLC. This conclusion has notable importance in terms of the biological characterization of early-stage tumours and therapeutic opportunities.

Aged↗

PubMed2004

Angiogenesis in intracranial meningiomas: immunohistochemical and molecular study.

Much of the morbidity of intracranial meningiomas is related to the degree of tumour vascularity and the extent of peritumoural vasogenic oedema. Several studies have shown that vascular endothelial growth factor (VEGF) is up-regulated in meningiomas, although its relationship with tumour vasculature is still unclear. In order to better understand the angiogenic assessment of intracranial meningiomas, we analysed its vascular pattern, both as number and as morphologic configuration of microvessels. Moreover, we investigated the mRNA-VEGF expression, relating this expression to vascular pattern. A total of 40 intracranial meningiomas, classified as benign (31 cases), atypical (7 cases), and anaplastic (2 cases) were analysed. RT-PCR analyses of mRNA-VEGF and competitive-PCR were performed. VEGF expression and microvessel density (MVD) were also immunohistochemically investigated. Grade II-III meningiomas showed numerous small microvessels (mean: 34), while the majority of Grade I showed few larger vessels (mean: 13.09) (P = 0.000003). A microvessel pattern overlapping into atypical subtype was found in eignt of the 31 (25.8%) Grade I meningiomas. A significant association was found between grading and vascular pattern (P = 0.0002), as well as between the MVD and the immunohistochemical expression of VEGF (P = 0.0005). The expression of mRNA agreed with the immunohistochemical expression of the protein (P < 0.0001). A total of 39 cases expressed the 121 VEGF isoform and, among these, 28 cases also expressed the 165 isoform. Only 9 cases expressed both isoforms 165 and 189. Grade II and III meningiomas showed a preponderant expression of soluble isoforms (121 and 165). These results prompt us to speculate that the microvessel pattern could underlie a higher metabolic demand, probably due to a rapid growth with a consequent worse clinical behaviour of the tumour. In this sense, the vascular pattern may be used as a prognostic factor, in order to mostly focus attention on those Grade I meningiomas which have a higher likelihood of either recurrence or development of perilesional oedema. The pattern of vasculature itself seems to be dependent on the types of VEGF isoforms: the Grade II-III meningiomas (that presented numerous microvessels) expressed the soluble isoforms 121 and 165, while the isoform 189 was more frequently detected in Grade I meningiomas.

Adult↗

PubMed2004

Thyroid papillary carcinoma: preliminary evidence for a germ-line single nucleotide polymorphism in the Fas gene.

The expression of Fas in thyroid tumours and Graves' disease was analysed by mRNA transcript expression. As compared with unaffected thyroid tissue, Fas expression was enhanced in Graves' disease, adenomas, and papillary and follicular carcinomas. This pattern was also reflected in immunohistochemical studies. The PCR single-strand conformational polymorphism (SSCP) method and DNA sequencing were used to analyse Fas exons 1-9. The study was carried out on five different histotypes of thyroid tumours (n=93) and tissue from Graves' disease patients. As compared with a group of healthy blood donors (n=64), a significant association (P=0.006) emerged between papillary thyroid carcinoma and a silent single nucleotide polymorphism (SNP, 988C-->T) in exon 7 of the Fas gene. Other forms of thyroid pathology were not associated with the above polymorphism. Patients with neoplasia showed the same SNP in tumour tissue, in the unaffected contralateral thyroid lobe, and in peripheral blood cells. Thus, the 988C-->T polymorphism appeared to be of germ-line origin.

Adenoma↗

PubMed2003

Evaluation of telomerase in non-melanoma skin cancer.

Telomerase, a ribonucleoprotein, is capable of adding telomeric sequences (TTAGGG hexameric repeats) to the ends of chromosomes and, thereby, halting the erosion of chromosome at each cell division. Whereas most normal somatic cells contain minimal or no detectable telomerase activity, most immortal and tumour cells exhibit significant levels of telomerase activity and show no net loss of telomere length during proliferation. The evaluation of telomerase has been proposed for diagnostic and therapeutic purposes in human cancer. Skin cancer is the most common cancer in humans; the precise molecular events in skin carcinogenesis are numerous and complicated and not yet completely clarified. In this study, we evaluated telomerase in 35 basal cell carcinomas and in 14 squamous cell carcinomas in order to determine if activation of the telomerase enzyme was a pivotal step in the development of skin cancer and whether telomerase activity levels were different between the two histotypes. A higher enzymatic level was shown to be associated with squamous cell carcinomas, while low levels were mainly detected in the basal cell histotype (chi2 test; p=0.02). Telomerase complex activity is dependent on its catalytic subunit, telomerase reverse transcriptase hTERT. By reverse transcription-PCR, using primers within the reverse transcriptase domain of hTERT, we observed a significant correlation between hTERT expression and telomerase activity in our skin tumour samples (p=0.0003). We detected the presence of multiple, alternately spliced transcripts, corresponding to full-length messages as well as spliced messages with critical reverse transcriptase motifs deleted. A higher telomerase messenger level was shown to be associated with squamous cell carcinomas (chi2 test; p<0.0001), as for telomerase activity. Our results provide arguments supporting the role of telomerase in skin cancer and suggest RT-PCR of telomerase RNA as a tool easier and faster than TRAP assay to identify more aggressive malignancies among non-melanoma skin specimens.

Adult↗

PubMed2003

Telomerase in intracranial meningiomas.

Telomere length maintenance is essential for tumorigenesis; most human tumors stabilize their chromosome ends via the activity of a specialized reverse transcriptase, telomerase, that uses the template region of the RNA moiety complementary to the TTAGGG repeat to synthesize one strand of telomeric DNA. Meningiomas are estimated to constitute between 13% and 26% of primary intracranial tumors. The aim of this study was to evaluate telomerase activity and its messenger expression in meningiomas in relation to their different histologic pattern and grade of cytonuclear atypies, which are associated with relapse, and consequently represent the most important parameter for the evaluation of the clinical behavior of this tumor. Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay in 32 meningiomas (26 typical and 6 atypical/anaplastic). Telomerase messenger expression (hTERT mRNA) was evaluated by reverse transcription-PCR analysis in the same group of tumors. Telomerase activity ranged from undetectable to low levels in 19/26 (73%) of typical meningiomas, while all the atypical/anaplastic meningiomas showed medium-high levels of activity (>3 TPG units, median value), (chi(2) test; p=0.001). The levels of telomerase in terms of its messenger level expression overlapped the activity; a significant association between telomerase activity and hTERT mRNA expression was also found (chi(2) test; p=0.01). Moreover, 2 atypical/anaplastic meningiomas of our series relapsed; in these samples we found high levels of telomerase, both in terms of activity and mRNA expression. Telomerase activity and its hTERT mRNA expression tended to increase as the histologic grading of intracranial tumors increased, suggesting a role of telomerase reactivation in the progression of these tumors. Moreover, our results indicate RT-PCR assay as a rapid tool to identify and quantify telomerase RNA in intracranial meningiomas as in other human tumor models.

Brain Neoplasms↗

PubMed2002

A high vascular count and overexpression of vascular endothelial growth factor are associated with unfavourable prognosis in operated small cell lung carcinoma.

It has been widely demonstrated that neo-angiogenesis and its mediators (i.e. vascular endothelial growth factor), represent useful indicators of poor prognosis in non small cell lung carcinoma. In order to verify whether neovascularization and vascular endothelial growth factor may be considered useful markers of clinical outcome also in the small cell lung cancer subgroup, we retrospectively investigated a series of 75 patients with small cell lung carcinoma treated by surgery between 1980 and 1990. Immunohistochemically-detected microvessels and vascular endothelial growth factor expressing cells were significantly associated with poor prognosis, as well as with nodal status and pathological stage. In fact, patients whose tumours had vascular count and vascular endothelial growth factor expression higher than median value of the entire series (59 vessels per 0.74 mm(2) and 50% of positive cells, respectively), showed a shorter overall and disease-free survival (P=0.001, P=0.001; P=0.008, P=0.03). Moreover, the presence of hilar and/or mediastinal nodal metastasis and advanced stage significantly affected overall and disease-free interval (P=0.00009, P=0.00001; P=0.0001, P=0.00001). At multivariate analysis, only vascular endothelial growth factor expression retained its influence on overall survival (P=0.001), suggesting that angiogenic phenomenon may have an important role in the clinical behaviour of this lung cancer subgroup.

Adult↗

PubMed2002

Meningioma-associated brain oedema: the role of angiogenic factors and pial blood supply.

BACKGROUND: Approximately 60% of meningiomas are associated with perilesional brain oedema. Several aspects have been evaluated in order to understand the pathophysiological mechanisms of oedema (age, sex of the patient, size and location of the tumour, histotype, grading), although at present they have yet to be completely clarified. We focused on pial blood supply, microvascular density (MVD) and angiogenic growth factors (i.e. vascular endothelial growth factor--VEGF) in order to evaluate their putative role in the development of brain oedema. METHODS: We retrospectively studied 55 patients with intracranial meningiomas. Computerized tomography (CT) and angiographic studies were obtained in all cases. The angiograms provided an accurate differentiation between pial and dural blood supply, concomitantly with its semi-quantitative evaluation. The location and the volume of oedema, in relation to the meningioma surface, was evaluated using CT scans, as an oedema index (E/I). We also determined the expression of VEGF and MVD using standard immunohistochemical methods. RESULTS: Thirty-two out of 55 meningiomas presented peritumoural oedema, with an angiographic blush ranging from 2 to 4; VEGF protein was expressed in 27 out of 32 cases, independent of grade or histotype of tumours. In all patients, MVD ranged from 4 to 33.3 vessels (median value: 10.6). A significant relationship was found between the expression of VEGF and MVD (p = 0.0003) and between VEGF and E/I (p = 0.0023). Moreover, the E/I ratio was related to the blush (p = 0.0005). A significant association was also present between VEGF expression and pial blush (p = 0.0001). CONCLUSION: Our data confirm the central role of VEGF and pial blood supply in the pathogenesis of peritumoural oedema and support the hypothesis that the development of oedema in meningioma is vasogenic in type.

Adult↗

PubMed2002

Identification of Fas (APO-1/CD95) and p53 gene mutations in non-small cell lung cancer.

Fas (APO-1/CD95) is a broadly expressed death receptor involved in a series of physiological and pathological apoptotic processes. One of the possible mechanisms for resistance to apoptosis signaling in the immune system as well as in the pathogenesis of non-lymphoid malignancies is the presence of Fas mutations within the entire gene. We investigated, in 79 non-small cell lung cancer (NSCLC) samples, the promoter and the entire coding region of the Fas gene by polymerase chain reaction, single strand conformation polymorphism and DNA sequencing in order to detect putative alterations. Sixteen of 79 tumor samples (20.2%) were found to have Fas alterations, either in promoter or exon region. Since the loss of Fas apoptotic function might be linked to p53 alterations, which are often involved in the development of NSCLC, we analyzed p53 status in 40 of the 79 NSCLC samples. p53 mutations were found to be more frequently present than Fas gene alterations (25 out of 40 cases, 62.5%). These data increase the knowledge regarding mutations of apoptosis-genes involved in the pathogenesis of NSCLC, and give benefits for the clinical management of this type of tumor.

Adenocarcinoma↗

PubMed2002

Evaluation of telomerase mRNA (hTERT) in colon cancer.

Telomerase activation, a cardinal requirement for immortalization, is a crucial step in the development of malignancy and requires the induction of the catalytic component, human telomerase reverse transcriptase (hTERT), encoded by the hTERT gene. By reverse transcription-PCR, using primers within the reverse transcriptase domain of hTERT, we investigated telomerase messenger in 8 adenomatous and 9 dysplastic polyps, and in 32 paired cancer-normal mucosa specimens, one liver and one spleen metastasis from patients resected for sporadic colorectal cancer. Telomerase messenger was absent or very low in normal mucosa and in adenomatous polyps. Dysplastic polyps and adenocarcinoma samples showed hTERT mRNA, with higher levels in cancer tissues compared to dysplastic lesions. A high telomerase messenger level was shown to be associated with late-staged cancers and with metastasis; thus, detection of telomerase messenger may be useful in the early diagnosis of colon cancer, and telomerase may be a new target for therapeutic intervention.

Adenoma↗

PubMed2002

Evaluation of telomerase in the development and progression of colon cancer.

Telomerase activity, a cardinal requirement for immortalization, is a crucial step in the development of cancer and has been studied in many kinds of malignant tumours for clinical diagnostic and/or prognostic utilities. Using a PCR-based TRAP assay, we investigated telomerase activity in 8 adenomatous polyps, 9 dysplastic polyps, and in 36 paired cancer-normal mucosa specimens, one liver and one spleen metastasis from patients resected for sporadic colorectal cancer. Telomerase was absent or very low in normal mucosa and in adenomatous polyps. Dysplastic polyps and adenocarcinoma samples showed telomerase activity, with higher levels in cancer tissues compared to dysplastic lesions. A high telomerase activity was shown to be associated with late-staged cancers and metastasis, providing arguments supporting the role of telomerase not only in the development but also in the progression of colorectal carcinoma. Moreover, telomerase evaluation may help to confirm the malignant transformation in polypoid colorectal lesions with different levels of dysplastic alterations.

Adenocarcinoma↗

PubMed2001

Alterations of Fas (APO-1/CD 95) gene and its relationship with p53 in non small cell lung cancer.

The Fas (APO-1/CD95) system regulates a number of physiological and pathological processes of cell death. The ligand for Fas induces apoptosis by interacting with a transmembrane cell surface Fas receptor. The key role of the Fas system has been studied mostly in the immune system, but Fas mutations, one of the possible mechanisms for resistance to apoptosis signaling, may be involved in the pathogenesis of non-lymphoid malignancies as well. To better understand the potential involvement of Fas system in non-small cell lung cancer (NSCLC) we evaluated Fas and Fas-ligand mRNA expression by polymerase chain reaction in 102 tumor samples and in 44 normal surrounding tissues. Although over 60% of the human NSCLC analysed expressed both genes, they seem to be unable to induce apoptosis in vivo by autocrine suicide. In this regard, we investigated in 79 cases, the promoter and the entire coding region of the Fas gene by polymerase chain reaction, single strand conformation polymorphism and DNA sequencing for detecting putative alterations. Sixteen tumors (20.25 %) were found to have Fas alterations, in promoter and/or exon region. In all cases samples carried heterozygous alterations and mostly showed simultaneous mutations of p53 gene. Moreover, the quantitative analysis of Fas mRNA expression showed high levels of Fas messenger associated with p53 wild-type status alone. Taken together, these findings point to an involvement of Fas/Fas-ligand system in the development of NSCLC, suggesting that the loss of its apoptotic function might be linked to p53 alterations which contribute to the self-maintenance of cancer cells.

Apoptosis↗

PubMed2001

The multimodality treatment of thymic carcinoma.

OBJECTIVES: Thymic carcinoma is a rare neoplasm more invasive and with a poorer prognosis than ordinary thymoma. Complete curative resection is sometimes not possible, but good response rates to chemotherapy are reported in literature. We report our experience with seven cases of thymic carcinoma, who took part to a multimodality treatment including neoadjuvant chemotherapy, surgery and post-operative radiotherapy in our center. METHODS: Since June 1989, seven previously untreated patients were enrolled. The primary chemotherapy consisted of three courses of cisplatin (P; 75 mg/m(2) i.v., day 1), epidoxorubicin (E; 100 mg/m(2) i.v., day 1) and etoposide (VP16; 120 mg/m(2) i.v., days 1, 3 and 5), every 3 weeks. Surgery was performed following complete hematological recovery. After surgery, all patients underwent radiation therapy to the tumor areas, operatively marked with clips, at doses of 45 (complete resection) or 60 Gy (incomplete resection). RESULTS: The pre-operative diagnosis of thymic carcinoma was performed in four cases by a mediastinotomy, and in the remaining cases, by an ultrasound-guided (n=2) or a computed tompography-guided (n=1) fine needle aspiration. All patients responded (one completely) to the chemotherapy regimen. Surgical resection was complete in four cases (histological examination negative in one case). Three patients are still alive and well (62-136 months from the diagnosis), two are alive with relapse at 16 and 85 months, one patient died at 86 months from another cause, and one patient died at 18 months from local relapse and lung metastases. CONCLUSIONS: A pre-operative shrinkage of the thymic carcinoma by means of neoadjuvant multi-drug chemotherapy may improve the resectability, and therefore, the survival rate. Our experience, although preliminary, is encouraging and merits additional study in a multicenter trial with a sufficient number of patients to draw definitive conclusions.

Adult↗

PubMed2001

Thymic carcinoma: a report of 13 cases.

OBJECTIVE: Thymic carcinoma is a rare thymic neoplasm. It is more invasive and has a poorer prognosis than thymoma. We report our experience in the treatment of 13 thymic carcinomas. METHODS: Thirteen patients with histologically confirmed thymic carcinoma were treated from June 1989. Six patients underwent surgery, followed by adjuvant therapy. Seven patients underwent neoadjuvant chemotherapy, followed by surgery and post-operative radiotherapy. RESULTS: The diagnosis of thymic carcinoma was achieved in six cases by a mediastinotomy, in three cases by a ultrasound-guided or a CT-guided fine needle aspiration and in three cases the pre-operative diagnosis was thymoma. In one case we did not have the histological diagnosis. All seven patients treated with neoadjuvant chemotherapy responded. The surgical resection was complete in seven cases. Eight patients are still alive 8-142 months from the diagnosis, and six are disease-free. CONCLUSIONS: Our experience supports the role of surgery and post-operative radiotherapy in thymic carcinomas. Pre-operative treatment of such neoplasms by multi-drug chemotherapy may improve the resectability and the survival rate.

Adult↗

PubMed2001

Inhibition of growth factor production and angiogenesis in human cancer cells by ZD1839 (Iressa), a selective epidermal growth factor receptor tyrosine kinase inhibitor.

The transforming growth factor-alpha/epidermal growth factor receptor (TGF-alpha-EGFR) autocrine pathway, which is involved in the development and the progression of human epithelial cancers, controls, in part, the production of angiogenic factors. These angiogenic factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are secreted by cancer cells to stimulate normal endothelial cell growth through paracrine mechanisms. ZD1839 (Iressa) is a p.o.-active, selective EGFR-tyrosine kinase inhibitor (TKI) in clinical trials in cancer patients. In this study, we evaluated the antiangiogenic and antitumor activity of ZD1839 in human colon (GEO, SW480, and CaCo2), breast (ZR-75-1 and MCF-7 ADR), ovarian (OVCAR-3), and gastric (KATO III and N87) cancer cells that coexpress TGF-alpha and EGFR. ZD1839 treatment determined a dose- and time-dependent growth inhibition accompanied by the decrease of VEGF, bFGF and TGF-alpha production in vitro. Treatment of immunodeficient mice bearing well-established, palpable GEO xenografts with ZD1839 determined a cytostatic dose-dependent tumor growth inhibition. Immunohistochemical analysis of GEO tumor xenografts after ZD1839 treatment revealed a significant dose-dependent reduction of TGF-alpha, bFGF, and VEGF expression in cancer cells and of neoangiogenesis, as determined by microvessel count. Furthermore, the antitumor activity of ZD1839 was potentiated in combination with the cytotoxic drug paclitaxel in GEO tumor xenografts. Tumor regression was observed in all mice after treatment with ZD1839 plus paclitaxel, and it was accompanied by a significant potentiation in inhibition of TGF-alpha, VEGF, and bFGF expression with a few or no microvessels. Furthermore, 6 of 16 mice bearing well-established, palpable GEO xenografts had no histological evidence of GEO tumors at the end of treatment with ZD1839 plus paclitaxel. These results demonstrate that the antitumor effect of ZD1839 is accompanied by inhibition in the production of autocrine and paracrine growth factors that sustain autonomous local growth and facilitate angiogenesis, and that this effect can be potentiated by the combined treatment with certain cytotoxic drugs, such as paclitaxel.

Angiogenesis Inhibitors↗

PubMed2001

Combined blockade of protein kinase A and bcl-2 by antisense strategy induces apoptosis and inhibits tumor growth and angiogenesis.

Protein kinase A type I (PKAI) plays a key role in neoplastic transformation, conveys mitogenic signals from different sources, and is overexpressed in the majority of human tumors. Inhibition of PKAI by different tools results in cancer-cell growth inhibition in vitro and in vivo. We and others have recently shown that a novel class of mixed-backbone oligonucleotides targeting the PKAI subunit RIalpha exhibits improved pharmacokinetic properties and antitumor activity accompanied by increased apoptosis in several human cancer types in vitro and in vivo. The role of bcl-2 in the control of apoptosis has been widely documented, and the inhibition of bcl-2 expression and function may have important therapeutic implications. In fact, oligonucleotides antisense bcl-2 have shown antitumor activity in animal models and have successfully completed early clinical trials. Recent studies have demonstrated a direct role of PKA in the regulation of the bcl-2-dependent apoptotic pathway. Therefore, we have investigated the combined blockade of PKA and bcl-2 by antisense strategy as a potential therapeutic approach. The novel hybrid DNA/RNA mixed-backbone oligonucleotide antisense RIalpha (AS RIalpha) in combination with the antisense bcl-2 (AS bcl-2), cooperatively inhibited bcl-2 expression and soft agar growth and induced apoptosis in different human cancer cell lines. p.o. administration of AS RIalpha in combination with i.p. AS bcl-2 caused a marked antitumor effect and a significant prolongation of survival in nude mice bearing human colon cancer xenografts. Moreover, histochemical analysis of tumor specimens showed inhibition of RIalpha and Ki67 expression, inhibition of angiogenesis, and parallel induction of apoptosis in vivo. The results of our study imply an interaction between the PKA and bcl-2 signaling pathways and, because both antisenses have now entered Phase II trials, provide the rationale to translate this novel therapeutic strategy in a clinical setting.

Animals↗

PubMed2001

Oral administration of a novel taxane, an antisense oligonucleotide targeting protein kinase A, and the epidermal growth factor receptor inhibitor Iressa causes cooperative antitumor and antiangiogenic activity.

PURPOSE: Protein kinase A type I (PKAI) and the epidermal growth factor receptor (EGFR) play a role in neoplastic transformation and interact with each other in transducing mitogenic signals. We developed different PKAI and EGFR inhibitors, demonstrating their cooperation with cytotoxic drugs and the therapeutic potential of the combined blockade of PKAI and EGFR. In this study, we investigated the effect of orally active PKAI and EGFR inhibitors in combination with a novel taxane. EXPERIMENTAL DESIGN: We combined a hybrid PKAI antisense oligonucleotide sequence (AS-PKAI), the EGFR inhibitor ZD1839 (Iressa), and the taxane IDN5109, studying their effect on human cancer growth, apoptosis, and angiogenesis and measuring vascular endothelial growth factor (VEGF) expression and vessel formation in vitro and after oral administration in nude mice. RESULTS: We demonstrated cooperative growth inhibitory and proapoptotic effects and inhibition of VEGF expression with any combination of two drugs and a marked synergistic effect when all three agents were combined. Oral administration of AS-PKAI, ZD1839, and IDN5109 in combination to nude mice caused a remarkable antitumor effect with no histological evidence of tumors in 50% of mice 5 weeks after treatment withdrawal, accompanied by complete suppression of vessel formation and VEGF expression. CONCLUSION: This is the first demonstration of the cooperative antitumor and antiangiogenic activity of three novel agents that block multiple signaling pathways after oral administration. Because all agents are under clinical evaluation in cancer patients, our results provide a rationale to translate this feasible therapeutic strategy in a clinical setting.

Administration, Oral↗