P17.13.A Verteporfin inhibits autophagy in glioblastoma cell lines

Background

Glioblastoma (GBM) is the most common primary brain tumor with a poor prognosis, characterized by a high cellular heterogeneity and invasiveness. Multi-drug resistance (MDR), the blood brain barrier (BEE) and DNA repair systems let the survival of tumor cells, making the treatment with chemo and radiotherapy not effective. Autophagy is a physiological mechanism that allows the recycling of damaged proteins and organelles, in order to protect the correct cell turnover. However, in GBM this process promotes survival and proliferation in stressful conditions such as after a chemo and / or radiotherapy treatment. The Hippo pathway is an extremely important molecular signaling because it is involved in various tumorigenesis processes, for instance the epithelium-mesenchymal transition (EMT), in the increase of stemness, mechanotransduction and chemoresistance.

Material and Methods

The modulation of autophagy was evaluated in GBM cell lines (U87MG, T98G and A172) exploiting a fluorescent detection that allowed the quantification of the autophagosomal activity present into the cell lines. The rate of autophagy was assessed after the cell lines pharmacological treatment with Hippo pathway inhibitors, Verteporfin 2uM (VP) for 24h, Latrunculin 0,5uM (LAT) for 3h and Cytochalasin 1uM (CIT) for 3h, with Doxorubicin 0,5uM (DOX) for 24h and with the drugs combination (DOX-VP, DOX-LAT and DOX-CIT). Moreover, the expression of the autophagy marker LC3II / I was evaluated in all three GBM cell lines by Western Blotting (WB) experiments. To perform this technique, the cells were treated with DOX and Hippo pathway inhibitors respecting the pharmacological treatment previously used. Then, the proteins were extracted, quantified and finally the WB was performed.

Results

The results obtained showed that the three GBM cell lines without any drugs were marked by high levels of autophagy, similar to the cells treated with Rapamycin, an autophagy inducer. Moreover, the autophagy rate was definitely reduced after treatment with VP and DOX-VP in all three cell lines, including the chemoresistant T98G. Conversely, the other two Hippo pathway inhibitors (LAT-CIT) and DOX did not significantly change the rate of autophagy. The expression of LC3II / I was particularly low after treatment with VP and DOX-VP in all three cell lines while the other two inhibitors did not significantly change its expression.

Conclusion

In conclusion, these data demonstrated that the three GBM cell lines (U87MG, T98G and A172) are characterized by high levels of autophagy and the inhibition of the Hippo pathway with VP and especially the combination DOX-VP reduced the activation of this protumoral molecular mechanism in GBM cell lines.

P06.07 Germline mutation of SMARCE1 gene in a family with spinal meningiomas

BACKGROUND

Meningioma is the most common benign primary intracranial tumor, arising from arachnoid cells of the meninges, but in 20% of cases displays aggressive behavior. Meningiomas are mainly sporadic and the familial forms are very rare. Meningioma account for a small subset (1–4%) of all pediatric brain tumors and may be associated with hereditary tumor predisposition syndrome caused by germline mutations of NF2, SMARCB1, SUFU, and SMARCE1 genes.

MATERIAL AND METHODS

We present a case of a 16-year-old girl with spinal clear cell meningiomas (CCMs) WHO II with a second spinal lesion identified during the follow-up. Considering the multiple lesions, we performed Whole Exome Sequencing (WES) on DNA from peripheral blood to search for an underlying CCMs tumor predisposition syndrome (#607174).

RESULTS

We identified a heterozygous frameshift variant c.439delA (p.Ser147fs) in SMARCE1, chromatin remodelling factor that acts as a tumor suppressor gene. Meningioma analysis by Sanger sequencing showed a loss of heterozygosity (LOH) of the wild-type allele. We identified the c.439delA in the constitutional DNA of the father and the sister but not in the mother. At the moment, the father is asymptomatic and the 14 years old sister showed two spinal lesions (meningiomas likely) at the first MRI.

CONCLUSION

We report a family study of hereditary tumor predisposition syndrome to CCMs with SMARCE1 mutation in which are present two asymptomatic carriers with different ages and gender. The asymptomatic carriers will undergo neurological examination and MRI of the brain and spine, according to a screening protocol. The incomplete penetrance phenomenon is known in SMARCE1-related families with CCMs and it is probably due to the interaction of SMARCE1 with yet unidentified genes.

P04.20 The role of YAP in Glioblastoma cell lines

BACKGROUND

Glioblastoma (GBM) is a primary human malignant brain tumor, the most common in adults. Several studies have highlighted the Hippo-pathway as a cancer signalling network. The Hippo pathway is an evolutionarily conserved signal cascade, which is involved in the control of organ growth. Dysregulations among this pathway have been found in lung, ovarian, liver and colorectal cancer. The key downstream effector of the Hippo-pathway is the Yes-associated protein (YAP); in the nucleus, its function as transcription co-activator is to interact with transcription factors, resulting in the expression of target genes involved in pro-proliferating and anti-apoptotic programs.

MATERIAL AND METHODS

Using western blotting analysis, we determined the nuclear expression of YAP on three GBM cell lines (U87MG, T98G and A172). To investigate which inhibitors against the Hippo-pathway were the most efficient, we performed a cytotoxic assay: we treated all the three cell lines with different inhibitors such as Verteporfin (VP), Cytochalasin D (CIT), Latrunculin A (LAT), Dobutamine (DOB) and Y27632. Afterwards, we performed a treatment using Doxorubicin (DOX) combined with the inhibitors, evaluating its cytotoxic effect on our cell lines, through cell viability experiments. More western blotting experiments were performed to investigate the oncogenic role of YAP at nucleus level. Furthermore, preliminary experiments have been conducted in order to investigate the apoptosis, senescence and autophagy modulation due to the Hippo-pathway.

RESULTS

We showed our cell lines express nuclear YAP. We assessed the efficiency of the main inhibitors against Hippo-pathway, proving that VP, LAT A and CIT show a strong cytostatic effect, linked to time increase; plus we saw a cytotoxic effect on T98G. The association of DOX with selected inhibitors is able to reduce cell viability and nuclear YAP expression rate in all three GBM lines. Finally, preliminary experiments were set up to assess how and if the mechanisms of apoptosis, autophagy and senescence were affected by the Hippo-pathway. The combination of DOX with inhibitors promotes resistance to apoptosis.

CONCLUSION

Our results show that nuclear YAP is present in all tumor lines, thus confirming that this molecular pathway is functioning in GBM lines. Nuclear YAP is more highly expressed after DOX administration. Moreover, the combined treatment (DOX with Hippo-pathway inhibitors) reduces both cell proliferation and viability, and increases the rate of apoptosis. Preliminary experiments on senescence and autophagy were used to determine the best Hippo-pathway inhibitor. These data demonstrate that the Hippo-pathway plays a crucial role in GBM proliferation and resistance to apoptosis. Inhibiting this pathway and in particular the transcription factor YAP, in association with DOX, might be an excellent therapeutic target.

P14.46 SUBEPENDYMAL GIANT CELLS ASTROCYTOMA (SEGA) IN TUBEROUS SCLEROSIS COMPLEX (TSC): A SERIES OF 31 PATIENTS

Background

Subependymal Giant Cells Astrocytomas (SEGAs) are characteristic of Tuberous Sclerosis Complex (TSC). They are usually benign tumors but may rapidly grow and cause hydrocephalus and raised intracranial pressure. Surgery is mandatory for large and symptomatic SEGAs

METHODS

31 patients harboring SEGAs in TSC were admitted for surgery. The main indications for surgery were tumor size and location, tumoral growth and cystization/hemorrhage, and hydrocephalus. In presence of symptomatic hydrocephalus firts surgery aimed to reduce intracranial pressure

RESULTS

Forty-four surgeries were performed in 31 patients achieving Gross Total and Subtotal Removal in 36 and 8 patients respectively. Recurrences occurred in 11 patients; nine of them were reoperated while two were administered therapy with m-TOR pathway inhibitors. Surgical morbidity and mortality accounted for 22.7% and 2.3% respectively; hydrocephalus was the main complication. After an average follow-up of 5 years, 90% of patients had no evidence of the disease and most (93,3%) had a good clinical status after surgery; 12 out of 30 patients (40%) had a VP-shunt for hydrocephalus

Conclusions

GTR is feasible and represents the treatment of choice of SEGAs in TSC. Therapy with m-TOR pathway inhibitors is to be considered in selected patients and especially in recurrences of SEGAs

P08.03 Separation and divorce after the diagnosis of child’s brain tumor

BACKGROUND

The diagnosis of a child’s brain tumor is a terrible situation for every member of the family. Numerous are the case of separations and divorces in Italy after a diagnosis of a child’s cancer. In particular, it happens with parents of children affected with brain tumor, being the most frequent solid tumor and the first cause of a tumor child’s death. The crisis related to the discovery of a tumor consists of four phases: shock, reaction, processing and re-orientation. It can happen that the diagnosis, experienced as a traumatic experience, can unite the family members as well as separate them. If there is already a process of family disintegration, a trauma can be a cause for breakup. The aim of our study was to investigate the possible correlation between brain tumor diagnosis in children and parental separations/divorces.

MATERIAL AND METHODS

We considered 427 patients afferent from 2012 to 2018 to the Neuro-Oncology Unit of the Meyer Children’s Hospital. Brain tumors are the 55–60% of all the tumors of our hospital, with an extra-regionality greater than 65%. The data analysis was conducted through information obtained directly from the families during follow-up visits or by telephone interviews.

RESULTS

Consistent with literature data in our series, the most frequent brain tumors were low-grade gliomas medulloblastomas, high-grade gliomas, ependymomas, midline diffuse gliomas, craniopharyngiomas, germ cell tumors and other rare pediatric tumors. The population was divided in 16 females and 18 males from different Italian regions: 65% from Central Italy, 23% from the South and Islands, 12% from the North. Data analysis showed 34 cases of separation and/or divorce, equal to 7% of our whole population, during treatment and more frequently at the end of treatment or after death. The median age of the 34 patients at the diagnosis of brain tumor was 9.5 years (range 1–19 years), with a higher percentage of cases of separations (41%) for parents of patients aged 10 years-14 years; 7 were the cases of separation and/or divorce when the diagnosis of brain tumor was made around 12–48 months after the child birth.

CONCLUSION

The diagnosis of a child’s brain tumor can generate stress in the family leading to different reactions, such as conflicts between parents or a real family crisis. The results of our study suggest a possible correlation between the diagnosis of a child’s brain tumor and the cases of separation and/or divorce. High risk medulloblastomas and high-grade gliomas that are likely to have a shorter path due to the unfavorable prognosis of the disease, appear to be the pathologies more often related to situations of family disputes. However, further investigations are necessary to verify the trend emerged from our study respect to the normal population.

P04.08 The role of SCN1A in glioblastomas and mixed neuronal glial tumors of pediatric age

BACKGROUND

Low and high grade gliomas, are the most common pediatric central nervous system (CNS) tumors and they show an extremely broad range of clinical behavior. Pediatric glioma is distinct from its adult counterpart with different genetic/epigenetic profile and biological features. Recently, several studies have shown the involvement of voltage-gated Na+ channels (VGSC) in different types of cancer, including gliomas. VGSC are multimeric transmembrane complexes, responsible for membrane depolarization in excitable cells playing an important role also in cell proliferation, migration, apoptosis and differentiation. VGSC are therapeutic targets in cardiovascular and neurological disorders and, in cancers, they could be a novel target for the development of promising anticancer therapy

MATERIAL AND METHODS

Firstly, we explored the genetic background of 9 pediatric glioblastomas (1–9 pGBMs), through whole-exome sequencing (WES) using HiSeq1000 platform (Illumina) with paired-end approach. On the basis of our results, we extended our study in another group of 16 epileptogenic mixed neuronal-glial tumors of pediatric age, (WHO grade I and II), through an amplicon approach (TSCA) using MiniSeq System platform (Illumina)

RESULTS

We identified variants in SCN1A gene in 3/9 pGBMs: case 3 had c.5782C>G in tumor and blood; case 5 showed c.2278G>T and two mosaic variants (c.5933C>T, 22% and c.4942C>T, 14%); case 6 showed c.667G>T variant only in tumor, and not in other non tumoral tissues (blood, urine and buccal swab). No variants in SCN1A were identified in a group of 16 pediatric mixed gliomas

CONCLUSION

In this study, we explore the genetic background of two groups of pediatric neuroepithelial brain tumors, through Next generation sequencing approach. We identified only in pGBMs variants in SCN1A gene that encoded for VGSCs and is involved in a spectrum of early-onset epileptic encephalopathies. None of our mutated patients showed history of epilepsy. Now, it is not clear the significance of these variants in pGBMs but interestingly, these variants are present in pGBM and not in mixed gliomas. Further studies on a big cohort of patients are needed to establish if they could play a role in pGBMs aggressiveness, migration and progression. Moreover, VGSCs could be a pharmacological target in pGBMs treatment

O6-Methylguanine-DNA-methyltransferase in recurring anaplastic ependymomas: PCR and immunohistochemistry

Ependymomas are the third most common brain tumor in children. The post surgical management is controversial. There are no convincing data on an effective role for chemotherapy. O(6)-Methylguanine-DNA-Methyltransferase (MGMT) is a DNA repair protein considered to be a chemosensitivity predictor. Hypermethylation of the MGMT gene promoter is an important cause of MGMT inactivation. We evaluated the MGMT gene promoter methylation and the immunohistochemical MGMT protein expression in 12 recurrent anaplastic ependymomas affecting children. Our purpose was to investigate the molecular rationale of the administration of alkylating agents to children affected by recurrent anaplastic ependymomas. All ependymomas lacked MGMT promoter hypermethylation and 9 (75%) showed high MGMT protein expression (>50% tumoral cells). Differences between different recurrences in the same patient were not observed. These results may indicate MGMT as a factor of chemoresistance to alkylating drugs in anaplastic ependymomas and support the uncertainties regarding the actual benefit of chemotherapy for patients with anaplastic ependymomas.

Microsatellite analysis in cutaneous malignant melanoma

The status and relevance of repetitive nucleotide sequences or microsatellite alterations in sporadic cutaneous melanoma has not been fully clarified. In this study we evaluated the presence of microsatellite alterations in a series of sporadic primary and metastatic melanomas in order to discover which genetic events may have a pathogenetic role in the development of this disease. Tumour samples were obtained from 21 patients with sporadic cutaneous melanoma, and from eight corresponding positive sentinel lymph nodes and one corresponding in-transit metastasis. In each specimen, selected neoplastic cells were procured by laser-assisted microdissection. Polymerase chain reaction-based microsatellite analysis was performed using a panel of 11 microsatellite markers, located at chromosome 2p, 4q, 9p, 16q, 17p and 21q. Overall, we found microsatellite alterations in five (23.8%) melanomas. Of these, one case showed alteration at marker D2S2182 and one at marker D17S261, whereas in another case alterations at three loci, D2S2182, D2S2291 and D9S171, were found. The fourth patient demonstrated an alteration at locus D9S171 both in the primary tumour and in the histologically positive sentinel lymph node. The fifth case was characterized by alterations at D2S2182 and at D17S250, whereas the corresponding in-transit metastasis showed the same alterations as the primary tumour and an additional alteration at IFN alpha. In conclusion, our study confirms previous observations that cutaneous melanomas demonstrate microsatellite alterations, although such instability occurs at a lower frequency than specific mismatch repair defects. Genetic analysis of metastatic lesions revealed that the same microsatellite alterations as in the primary tumour are seen, but additional genetic changes may develop during disease progression.

Up-regulation of cyclooxygenase 2 gene expression correlates with tumor angiogenesis in human colorectal cancer

BACKGROUND & AIMS

Recent studies have shown that cyclooxygenase (COX)-2 and its products, prostaglandins (PGs), may be involved in colorectal carcinogenesis. The aim of this study was to determine whether COX-2 expression and PGE(2) production correlate with microvessel density, vascular endothelial growth factor (VEGF) expression, and tumor metastasis in human colorectal cancer.

METHODS

Tumor samples and adjacent normal mucosa were obtained from 31 surgical specimens. Immunohistochemical expression of COX-2, VEGF, and CD31 was analyzed on paraffin-embedded tissue sections. COX-2 and COX-1 proteins were determined by Western blot analysis. COX-2 and VEGF messenger RNA expressions were evaluated using Northern blot analysis. PGE(2) production was determined by specific radioimmunoassay.

RESULTS

The immunohistochemical expressions of both COX-2 and VEGF were significantly correlated with microvessel density (P = 0.02 and P = 0.002, respectively). A significant correlation was found between COX-2 and VEGF expression (P = 0.004). Western analysis confirmed the up-regulation of COX-2 protein expression. COX-2 and VEGF genes were overexpressed in tumor specimens as compared with normal mucosa. PGE(2) levels were significantly higher in metastatic tumors than in nonmetastatic ones (P = 0.03).

CONCLUSIONS

COX-2 is related to tumor angiogenesis in colorectal cancer. It is likely that VEGF is one of the most important mediators of the COX-2 angiogenic pathway.

Inducible nitric oxide synthase expression in benign and malignant cutaneous melanocytic lesions

Nitric oxide (NO) is synthesized by nitric oxide synthases (NOS) and plays an important role in tumour growth. In this study, inducible NOS (iNOS) expression was evaluated by immunohistochemistry in 34 melanocytic naevi (13 common melanocytic naevi, six Spitz naevi, and 15 so-called 'dysplastic naevi'), ten cutaneous melanomas in situ, 50 stage I invasive melanomas, and eight subcutaneous metastases of melanoma. In addition, four samples of melanocytic naevi and four samples of invasive melanomas were collected in order to perform western blot and northern blot analysis. By immunohistochemistry, melanocytic naevi never expressed iNOS. Among cases of melanoma in situ, two were negative, seven displayed staining in less than 20% of melanoma cells, and positivity was observed in 21-50% of melanoma cells in only one case. iNOS expression was detected in 46 out of 50 invasive melanomas (92%). Among these cases, 18 showed positivity in less than 20% of melanoma cells, 18 showed positivity in 21-50% of melanoma cells, and ten showed iNOS expression in more than 50% of cells. Statistical analysis revealed a significant difference in iNOS expression between melanocytic naevi and cutaneous melanomas (p<0.001). In addition, iNOS expression was significantly higher in invasive melanomas than in melanomas in situ (p=0.01). Among primary cutaneous melanomas, no significant correlation was found between iNOS expression and histopathological parameters (histotype, level, thickness and presence of regression/inflammatory infiltrate) and disease-specific survival. In subcutaneous melanoma metastases, iNOS expression was diffuse in more than 50% of cells. Statistical analysis revealed that subcutaneous melanoma metastases showed greater iNOS immunoreactivity than invasive melanomas (p=0.02). Molecular analyses confirmed that iNOS mRNA and protein were highly expressed in melanoma samples. In conclusion, iNOS was constantly absent in melanocytic naevi, whereas it was frequently expressed in melanomas, with up-regulation of the enzyme paralleling tumour progression. These data suggest that iNOS may play a role in the malignant transformation of melanocytes and in tumour growth. In addition, iNOS may be useful as an immunohistochemical marker for malignant melanocytic lesions.

Downregulation of transforming growth factor beta type II receptor in laryngeal carcinogenesis

AIMS

To investigate whether anomalies of transforming growth factor beta type II receptor (TGF-beta RII) expression occur in the early stages of laryngeal carcinogenesis and to assess their importance in the development of laryngeal squamous cell carcinoma. TGF-beta RII status was examined in laryngeal premalignant lesions coupled with malignant evolution and compared with a control group of similar lesions without progression to cancer.

METHODS

Immunohistochemical staining for TGF-beta RII was performed on 15 paraffin wax embedded biopsies from patients with precancerous laryngeal lesions who subsequently developed invasive squamous cell carcinoma of the larynx, and on 30 control biopsies from patients who did not develop cancer in a comparable follow up period. In addition, DNA extracted from 18 preneoplastic lesions and eight squamous cell carcinomas was amplified by the polymerase chain reaction at the poly A and the poly GT regions of the TGF-beta RII gene.

RESULTS

In the group of lesions with progression to carcinoma, 11 of 15 cases showed loss (< 20% of epithelial cells) of TGF-beta RII immunoreactivity, whereas among non-evolved lesions only five of 30 had similar altered expression of the receptor (p < 0.001, two tailed Fisher's exact test). All squamous cell carcinomas showed a degree of receptor expression comparable with that of the corresponding preneoplastic lesion, with the exception of one case, in which loss of the receptor was evident only in invasive cancer. Mutation of the poly A sequence of the TGF-beta RII gene was identified in only one precancerous lesion and in the subsequent squamous cell carcinoma.

CONCLUSIONS

These findings indicate that the downregulation of TGF-beta RII is an early event in laryngeal carcinogenesis, which may result in the loss of TGF-beta mediated growth inhibition, thereby facilitating the progression of laryngeal precancerous lesions to squamous cell carcinoma.

Microsatellite instability as biomarker for risk of multiple primary malignancies of the upper aerodigestive tract

Head and neck cancer (HNC) patients are at high risk of developing second primary tumors of the upper aerodigestive tract and this is a chief cause of death. Genomic instability reflecting the propensity and the susceptibility of the genome to acquire multiple alterations is considered a driving force behind multiple carcinogenesis and the alterations of the length of single repetitive genomic sequences or microsatellite instability (MI), implicating impaired DNA repair mechanisms, and could be a sensitive marker for assessing genomic instability in multiple HNC. To investigate whether a genetic defect(s) involving the mismatch repair system constitutes a risk factor in patients with multiple head and neck cancer, we examined replication errors (RER) at 10 microsatellite loci in 21 primary and 5 second primary cancers in 21 patients with multiple malignancies of the upper aerodigestive tract, in comparison with match-paired primary HNC from patients without multiple malignancies. A RER+ phenotype (alterations at > or =2 loci) was observed at 10 microsatellite alterations on chromosomes 2, 3, 11, 17 in at least one tumor from 15 out of 21 (71.5%) patients with multiple primary cancers but only in 11 tumors from 40 (27.5%) HNC patients with single cancer (P=0.001). A RER+ phenotype was also associated with a positive familial cancer history (P=0.046). Our results suggest that a genetic instability may play an important role in the pathogenesis of multiple primary cancers and that testing for MI in a primary HNC may be useful in detecting patients with high risk for developing multiple malignancies of the upper aerodigestive tract.

Cyclooxygenase-2 pathway correlates with VEGF expression in head and neck cancer. Implications for tumor angiogenesis and metastasis

We evaluated the role of COX-2 pathway in 35 head and neck cancers (HNCs) by analyzing COX-2 expression and prostaglandin E2 (PGE2) production in relation to tumor angiogenesis and lymph node metastasis. COX-2 activity was also correlated to vascular endothelial growth factor (VEGF) mRNA and protein expression. COX-2 mRNA and protein expression was higher in tumor samples than in normal mucosa. PGE2 levels were higher in the tumor front zone in comparison with tumor core and normal mucosa (P<.0001). Specimens from patients with lymph node metastasis exhibited higher COX-2 protein expression (P=.0074), PGE2 levels (P=.0011) and microvessel density (P<.0001) than specimens from patients without metastasis. A significant correlation between COX-2 and tumor vascularization (r(s)=0.450, P=.007) as well as between COX-2 and microvessel density with VEGF expression in tumor tissues was found (r(s)=0.450, P=.007; r(s)=0.620, P=.0001, respectively). The induction of COX-2 mRNA and PGE2 synthesis by EGF and Escherichia coli lipopolysaccharide (LPS) in A-431 and SCC-9 cell lines, resulted in an increase in VEGF mRNA and protein production. Indomethacin and celecoxib reversed the EGF- and LPS-dependent COX-2, VEGF, and PGE2 increases. This study suggests a central role of COX-2 pathway in HNC angiogenesis by modulating VEGF production and indicates that COX-2 inhibitors may be useful in HNC treatment.

Prediction of recurrence by microsatellite analysis in head and neck cancer

We examined the possibility of using microsatellite alterations as markers to detect clonal tumor-derived cell populations in histopathologically negative surgical margins and cervical lymph nodes from head and neck cancer (HNC) patients. We used polymerase chain reaction (PCR)-based microsatellite analysis DNA to analyze primary tumors, paired surgical margins, and cervical lymph nodes from 41 HNC patients. Samples were scored for alterations as defined by the presence of new alleles (shifts) or loss of heterozygosity (LOH) at each of 10 markers. We identified 25 (61%) patients with primary HNC who appeared to have had a complete resection on the basis of the histopathological assessment and who were informative regarding microsatellite alterations in tumor tissue. In 11 of these 25 (44%) cases, PCR analysis of surgical margins showed the same microsatellite alterations as in the primary tumors. In 7 of these 11 patients, the carcinoma recurred locally, as compared with 1 out of 14 patients with negative margins (log rank test, P = 0.0049). Conversely, we were unable to detect clonal neoplastic cells in histopathologically negative lymph nodes examined by molecular analysis. Cox regression analysis showed that molecular positive margins were an independent prognostic factor (P = 0.04) for recurrence. This study demonstrates that microsatellite analysis may be a valuable tool for evaluating the risk of local recurrence.

Molecular genetic alterations of c-myc oncogene in superficial and locally advanced bladder cancer

OBJECTIVE

Gene activation and altered expression of cellular proto-oncogene are important mechanisms implicated in initiation and development processes of human cancer. It has already been shown that c-myc oncogene is implicated in the control of cell proliferation, apoptosis and differentiation.

METHODS

We have determined the methylation status, the presence of genetic amplification and the presence of m-RNA overexpression of c-myc gene in 31 samples from patients with bladder carcinomas.

RESULTS

Our data demonstrated the presence of c-myc gene amplification only in 5 of 15 superficial bladder carcinomas (p < 0.05). On the other hand, we did not find statistical significant correlation between the methylation, expression of c-myc gene and the clinical-histopathological parameters. A significant correlation (p < 0.05) was found between the methylation pattern and m-RNA overexpression of c-myc oncogene.

CONCLUSION

We demonstrate aberrant c-myc gene status in human bladder cancer. This oncogene is altered at different levels in bladder carcinoma genesis and progression.

Molecular detection of microsatellite instability in basal cell carcinoma

Several studies have shown that the presence of genetic instability can be associated to carcinogenesis process. The detection of microsatellite instability (MI) that consists of an expansion and/or deletion of DNA within repeat sequences, may constitute a sensitive marker for the presence of gene mutations. A series of 18 basal cell carcinoma (BCC) consecutive patients was examined for the presence of alteration in 12 DNA microsatellite markers, in order to better understand the molecular significance of MI in the genesis and progression of BCC. Molecular alterations were detected in 6 out of 12 analyzed microsatellite loci. Five out of 18 BCC samples showed loss of heterozygosity at chromosome loci localized in the vicinity of the tumor suppressor genes, whereas six out of 18 BCC patients presented at least one altered microsatellite (instability). We demonstrated molecular genetic alterations at 2p16 locus, in the proximity of MSH2 <mismatch repair> gene and 17p21, in the proximity of the p53 gene. These data validate and confirm a role of MI in genesis and progression of BCC, by analysis of markers localized at specific chromosome region in proximity of oncogenes and tumor suppressor genes.

Molecular alterations of E-cadherin gene: possible role in human bladder carcinogenesis

E-cadherin is a transmembrane glycoprotein which mediates a calcium dependent homophilic interaction among epithelial cells. The altered expression and gene mutations of E-cadherin adhesion molecule have been frequently observed in various tumors. Several invasive carcinomas showed cell-cell adhesion loss although the tumor cells expressed considerable amounts of E-cadherin protein. The purpose of this study was to evaluate the role of E-cadherin gene alterations in genesis and progression of bladder carcinoma by mutation analysis of coding region, expression analysis and microsatellite instability at E-cadherin chromosome locus. We analyzed 30 bladder carcinoma (28 transitional and 2 squamous cell carcinoma) at different stage and grade. The mutation analysis showed that in one case there was a presence of a point mutation at codon 846 that consisted of a G (AGC) to C (ACC) transversion resulting in the replacement of R to T. In another sample the sequence analysis revealed a same-sense mutation at the codon 785 (AAC - AAT). The study of E-cadherin mRNA by Northern blot analysis showed that there were no differences of mRNA levels between tumor and normal mucosa samples. We noted that invasive and anaplastic tumors showed a trend to loss of expression, even if we did not find any statistically significant differences. The microsatellite analysis showed the presence of genomic instability in proximity of the E-cadherin gene. Nine out of 30 (30%) specimens presented molecular alterations in at least one out of 2 loci (D16S260 and D16S301) analyzed. The comparison between microsatellite mutations and clinical-histopathological parameters revealed a higher number of alterations in invasive respect to superficial tumors (p=0.014). On the other hand, there were no statistical differences regarding the correlation with pathological grade. These observations, which, nevertheless, need to be confirmed in a larger number of patients, suggest that alterations of E-cadherin gene may be related to pathobiology of bladder cancer development and clinical progression.

Multiple primary tumors of the upper aerodigestive tract: is there a role for constitutional mutations in the p53 gene?

Head-and-neck cancer (HNC) patients have a high risk of developing second primary tumors of the upper aerodigestive tract, the main cause of death. Although the roles of tobacco and diet in multiple head-and-neck carcinogenesis have been thoroughly investigated, little is known about individual genetic susceptibility factors involved in this process. Genomic instability, reflecting the propensity and the susceptibility of the genome to acquire multiple alterations, could be considered a driving force behind multiple carcinogenesis. Mutation of the p53 tumor-suppressor gene has been proposed to play an important role in this process. Therefore, we evaluated the incidence of inherited p53 germ-line alteration(s) in a population of 24 consecutive HNC patients and their first-degree relatives affected by multiple malignancies as well as the occurrence of p53 somatic acquired mutation(s) in 16 cancers, including first and second primaries from 5 HNCs of the same group. Mutations in exons 4-11 of the p53 gene were investigated using SSCP-PCR analysis and DNA sequencing. Analysis was extended to the peripheral blood and cancer biopsies available from first-degree relatives of cancer-prone families with p53 germ-line mutations. p53 germ-line mutations were identified in the peripheral blood and corresponding cancers of 3 HNC patients who had multiple malignancies. The only missense mutation detected was mapped in exon 6; it is a GTG to GAG substitution with an amino acid change from Val to Glu at codon 197. The remaining 2 p53 germ-line mutations were single-nucleotide substitutions without amino acid change in exon 6 (codon 213, CGA to CGG) and in exon 8 (codon 295, CCT to CCC), respectively. These mutations were found in HNC patients with a family history of cancer. Abnormal expression of wild-type p53 protein in normal and pathological tissues from patients with the same sense single-nucleotide substitutions was detected by immuno-histochemistry.

Microsatellite alterations in superficial and locally advanced transitional cell carcinoma of the bladder

Recent studies described the existence of genetic instability associated with bladder carcinogenesis. Alterations at microsatellite loci constitute a recognized tumor marker of genome instability. A series of 21 transitional cell carcinomas of the bladder (10 superficial and 11 invasive carcinomas) was analyzed for the presence of alteration in 12 microsatellite loci, in order to detect the role of microsatellite instability in genesis and progression of human bladder cancer. Our preliminary results indicate a trend to presence of microsatellite instability (MI) in invasive and undifferentiated tumors compared to superficial and differentiated forms. Eight out of 11 T2-T4 tumors presented a number of altered microsatellite >/=2 compared to one out of 10 Ta-T1 bladder carcinomas (p=0.008). Moreover, 9 out of 15 (60%) G2-G3 tumors had significantly more unstable microsatellites than those differentiated (0 out of 6) (p=0.019). Our results provide an insight into the potential usefulness of microsatellite analysis of bladder carcinoma to better understand which neoplastic forms will evolve to invasive progression and indicate that pronounced MI may be associated with more aggressive bladder carcinomas.

Effect of 0.2 T static magnetic field on human neurons: remodeling and inhibition of signal transduction without genome instability

We describe the effect of the static magnetic field generated by a 0.2 T magnetic resonance tomograph on a normal human neuronal cell culture (FNC-B4). After 15 min exposure cells showed dramatic changes of morphology: they formed vortexes of cells and exposed branched neurites featuring synaptic buttons. At the same time, thymidine incorporation and inositol lipid signaling were significantly reduced. Control (sham exposed) or non-neuronal cells (mouse leukemia, and human breast carcinoma cells) did not show any alteration following exposure. Endothelin-1 release from FNC-B4 cells was also dramatically reduced after 5 min exposure. However, PCR analysis of 12 DNA microsatellites selected as gauges of genome instability, did not reveal any alteration following exposure, thus ruling out a direct effect of the magnetic field on DNA stability. These data can be interpreted as a specific effect of the static magnetic field on human neuronal cells and are consistent with the induction of remodeling and differentiation; they demonstrate that fields below 0.5 T have significant biological effects on human neurons.

The role of the detection of hematogenous micrometastasis in prostate adenocarcinoma and malignant melanoma by RT-PCR

Recent studies reported the possibility of detecting prostate adenocarcinoma and malignant melanoma cells in peripheral blood using RT-PCR of prostatic specific antigen (PSA), prostatic specific membrane antigen (PSMA) and Tyrosinase mRNAs. The PCR results showed high variability, ranging between 0% and 100% of positivity in patients with advanced disease. Our purpose was to evaluate the presence of tumor marker mRNAs in peripheral blood of prostate cancer and melanoma patients by means of RT-nested-PCR. We tested 70 and 36 peripheral blood samples from prostate carcinoma and malignant melanoma patients, respectively. The RT-PCR analysis showed the presence of PSA cDNA in 9 out of 70 (12.9%); PSMA cDNA in 14 out of 70 (20%); and Tyrosinase cDNA in 2 out of 36 (5.5%) peripheral blood samples from melanoma patients. Our study confirms the applicability of this sensitive method to monitor disease status. Although, the RT-nested-PCR of Tyrosinase is able to detect neoplastic cells in peripheral blood specimens, we suggest the necessity of a great caution in interpreting PCR results when the nested method has been used.

The high prevalence of thermolabile 5-10 methylenetetrahydrofolate reductase (MTHFR) in Italians is not associated to an increased risk for coronary artery disease (CAD)

Mild hyperhomocysteinemia was found to be related to venous thrombosis, cerebrovascular and coronary artery disease (CAD). Some recent studies suggested that a mutation in the gene encoding for 5-10 methylenetetrahydrofolate reductase (MTHFR), due to a transition C-->T at nucleotide 677, is a genetic risk factor for vascular disease. However, several further studies could not confirm this association. We investigated 84 patients with CAD who underwent percutaneous transluminal coronary angioplasty (PTCA) and 106 healthy subjects. The prevalence of the mutated homozygous genotype was much higher than in other Italian populations, Europeans or other major human groups, but no excess of the Val/Val homozygotes was found in patients (28.5%) with respect to healthy subjects (30.2%). Mutated homozygous MTHFR genotype (+/+) was not found to be related to the clinical manifestations of CAD, to the prevalence of the common risk factors and to the rate of restenosis. In conclusion, thermolabile MTHFR does not appear to be associated "per se" with the risk for CAD or for restenosis after PTCA. The high frequency of the +/+ genotype in our Italian population (from Tuscany) confirms a wide macroheterogeneity and suggests a microheterogeneity in the genotype frequencies of the different ethnic populations.

The use of RT-"nested" PCR of prostate specific antigen to detect hematogenous neoplastic cells in patients with prostate adenocarcinoma

The aim of this study was to determine the presence of hematogenous neoplastic cells in patients with prostate cancer. We used a reverse transcription (RT) "nested" polymerase chain reaction (PCR) of prostate-specific antigen (PSA) mRNA to detect the presence of circulating tumor cells in 52 patients who underwent radical prostatectomy with lymphadenectomy. Blood samples were obtained before and after the surgical manipulation. Seven (13.5%) preoperative samples presented evidence of circulating neoplastic cells. All postoperative specimens studied presented a negative result at analysis 24 h after surgical manipulation. Although we did not find a statistical correlation between the PSA-PCR results and clinical-histopathological parameters, the presence of circulating prostate cells was strongly correlated with an elevated Gleason score of primary tumor (P<0.01). Thus our data show the positive effect of surgical treatment in removing the metastases source. The sensitive RT-nested PCR assay may play a crucial role in the administration of adjuvant therapy of patients with prostate adenocarcinoma.

Abnormal c-myc oncogene DNA methylation in human bladder cancer: possible role in tumor progression

OBJECTIVE

It has been suggested that the hypermethylation of normally unmethylated DNA sequences plays a critical role in the genesis and progression of human tumors. Although the molecular bases of this mechanism have not been completely explained, the altered methylation pattern of the c-myc oncogene is supposed to represent an important step in tumor development.

METHODS

We have analyzed tissue samples from 47 urinary bladder tumors (43 primary transitional and 4 squamous cell carcinomas) and the respective blood with HpaII methyl-sensitive endonuclease digestion and the Southern blotting technique to detect the methylation pattern in a widespread area in and around the c-myc oncogene.

RESULTS

Data presented in this study showed significant differences between the c-myc methylation pattern and pathological grade (p < 0.05). On the other hand, we did not find a significant correlation between the c-myc methylation pattern and clinical stage. However, a variable covalent alteration of c-myc DNA existed in bladder cancer as compared to normal tissue.

CONCLUSION

Although the correlation between superficial and infiltrating forms was not statistically significant, we did, however, find differences in aggressive neoplastic behavior. This suggested that local hypermethylation may be considered as one potential mechanism for increasing genetic alterations in bladder cancer formation.