Giulio Maira

Regulation of the p27Kip1 tumor suppressor by miR‐221 and miR‐222 promotes cancer cell proliferation

MicroRNAs (miRNAs) are potent post‐transcriptional regulators of protein coding genes. Patterns of misexpression of miRNAs in cancer suggest key functions of miRNAs in tumorigenesis. However, current bioinformatics tools do not entirely support the identification and characterization of the mode of action of such miRNAs. Here, we used a novel functional genetic approach and identified miR‐221 and miR‐222 (miR‐221&222) as potent regulators of p27Kip1, a cell cycle inhibitor and tumor suppressor. Using miRNA inhibitors, we demonstrate that certain cancer cell lines require high activity of miR‐221&222 to maintain low p27Kip1 levels and continuous proliferation. Interestingly, high levels of miR‐221&222 appear in glioblastomas and correlate with low levels of p27Kip1 protein. Thus, deregulated expression of miR‐221&222 promotes cancerous growth by inhibiting the expression of p27Kip1.

The EphA2 Receptor Drives Self-Renewal and Tumorigenicity in Stem-Like Tumor-Propagating Cells from Human Glioblastomas

In human glioblastomas (hGBMs), tumor-propagating cells with stem-like characteristics (TPCs) represent a key therapeutic target. We found that the EphA2 receptor tyrosine kinase is overexpressed in hGBM TPCs. Cytofluorimetric sorting into EphA2(High) and EphA2(Low) populations demonstrated that EphA2 expression correlates with the size and tumor-propagating ability of the TPC pool in hGBMs. Both ephrinA1-Fc, which caused EphA2 downregulation in TPCs, and siRNA-mediated knockdown of EPHA2 expression suppressed TPCs self-renewal ex vivo and intracranial tumorigenicity, pointing to EphA2 downregulation as a causal event in the loss of TPCs tumorigenicity. Infusion of ephrinA1-Fc into intracranial xenografts elicited strong tumor-suppressing effects, suggestive of therapeutic applications.

Craniopharyngiomas of the third ventricle : Trans-lamina terminalis approach

OBJECTIVECraniopharyngiomas usually grow on the cisternal surface of the hypothalamic region; these tumors can also grow from the infundibulum or tuber cinereum on the floor of the third ventricle, developing exclusively into the third ventricle. The aim of the present work was to establish the usefulness of the pterional trans-lamina terminalis approach for the removal of these tumors. METHODSEight patients who were surgically treated for craniopharyngiomas located exclusively within the third ventricle were considered. The initial symptoms were acute hydrocephalus in two cases, psychological disturbances in two, amenorrhea in two, headaches in one, and hypopituitarism in one. The diagnoses were established, in all cases except one, with magnetic resonance imaging. In all cases, the tumor completely filled the third ventricle. RESULTSTotal removal of the lesion was achieved in seven cases. One patient underwent partial removal. In the immediate postoperative period, no major complications were observed. Five patients required replacement hormonal therapy. All patients returned to a normal life. Many months after surgery, two patients exhibited psychological disturbances and died, the first because of voluntary withdrawal of replacement therapy (12 mo after surgery) and the second because of a severe imbalance in body fluids and electrolytes, with a subsequent hyperosmolar coma (27 mo after surgery). Only one patient who underwent initial total removal experienced a small recurrence of the lesion (30 mo after surgery); after 3 years, the lesion exhibited unchanged size. CONCLUSIONIn our experience, the trans-lamina terminalis approach is a valid choice for the removal of purely intraventricular craniopharyngiomas. These tumors can be removed without significant sequelae related to the surgical approach. The proximity to the hypothalamus requires accurate neuroendocrine and electrolyte control in the postoperative period, in some cases even years after surgery.

Cerebrospinal fluid shunting for hydrocephalus in the adult: Factors related to shunt revision

Cerebrospinal fluid shunting procedures are widely employed in the treatment of hydrocephalus and other disturbances of the dynamics of cerebrospinal fluid. In spite of its popularity, this operation frequently requires surgical revision. A retrospective analysis of a series of 356 adults who underwent the insertion of a cerebrospinal fluid shunt between January 1970 and December 1988 was performed. The incidence of revision was analyzed, and an attempt was made to identify possible causal factors. The overall incidence of surgical revisions was 28.65%; the number of revisions in the same patient ranged between one and eight. The most frequent causes of revision were distal malposition, obstruction, and infection. A statistically significant difference (P less than 0.05) was found in both the risk of revision in patients who had undergone previous operations and those who had not and in the incidence of revision before and after January 1985. Meticulous surgical technique as well as perioperative antibiotic prophylaxis appear responsible for the latter. The differences in the incidence of revision among patients treated with different types of shunts and valves, though remarkable, is not statistically significant.

Prognostic significance of the Ki-67 labeling index in growth hormone-secreting pituitary adenomas.

CONTEXTnKi-67 is a marker of proliferation activity associated with invasiveness and prognosis in human tumors.nnnOBJECTIVEnThe aim of the study was to evaluate the Ki-67 index prognostic relevance in a group of acromegalic patients who underwent transsphenoidal surgery for a GH-secreting pituitary adenoma.nnnMATERIAL AND METHODSnWe selected 68 consecutive acromegalic patients referred to our hospital during a 5-yr period. The Ki-67 index was determined by immunohistochemistry on tissue samples obtained from each adenoma after surgery. Those patients who were not completely cured after surgery began medical therapy with somatostatin analogs (SSAs). Periodical pituitary magnetic resonance imaging and hormonal evaluation were performed during the follow-up.nnnRESULTSnTwenty-eight of 68 patients were cured after surgery (41%). Among the 40 patients treated with SSAs, 13 were considered uncontrolled. Pituitary magnetic resonance imaging showed residual/recurrent disease in 25 of 68 patients after 6 months. No correlation was found between Ki-67 index and age, tumor size, GH, or IGF-I plasma levels. Tumors described as having cavernous sinus invasion had a higher mean Ki-67 index as compared with noninvasive tumors (P < 0.01). The Ki-67 index was significantly lower in tumors in patients cured after surgery as compared with patients considered not cured (P < 0.01) and in tumors in patients controlled by SSA therapy as compared with patients considered as uncontrolled (P < 0.05).nnnCONCLUSIONnThe Ki-67 labeling index may predict clinical outcome in postsurgical management of acromegalic patients. We suggest routine Ki-67 evaluation in GH-secreting pituitary adenomas.

Cerebrospinal Fluid Pressure Studies in Normal Pressure Hydrocephalus and Cerebral Atrophy

The surgical results obtained with a cerebrospinal fluid (CSF) shunt operation in 13 patients considered to be suffering from normal pressure hydrocephalus have been correlated with the findings of the constant manometric infusion test (IT) and of prolonged intracranial pressure recordings. A positive IT, high amplitude CSF pulse pressure and large transitory increases of CSF pressure during sleep seem to be useful criteria for the surgical prognosis. Ten more patients affected by primary cerebral atrophy have also been studied. The data obtained in both groups of patients have been utilized for a possible pathogenetic interpretation of the syndrome.

In situ detection of telomerase catalytic subunit mRNA in glioblastoma multiforme

Activation of telomerase may allow unlimited cell proliferation and immortalization. One of the telomerase protein subunits has a reverse transcriptase (hTERT) activity that is essential for telomerase function and regulation. In human gliomas, telomerase is frequently associated with malignant tumor progression. In our study, we investigated the expression of hTERT at the cellular level in 34 primary de novo glioblastoma multiforme (GBM) by in situ hybridization ( ISH ). The expression of hTERT in tumor tissue was also assessed by RT‐PCR. In addition, telomerase activity measured by telomeric repeat amplification protocol (TRAP) and telomere length polymorphism assayed by telomere restriction fragment (TRF) Southern blot were investigated. We found that all GBM, including those with negative TRAP reaction, contained abundant amounts of cytoplasmic hTERT mRNA. Interestingly, the ISH analysis revealed that the hTERT mRNA was homogeneously expressed by the whole tumor cell population in about 60% of the GBM. In the remaining cases, hTERT was absent in subsets of tumor cells. TRF analysis, which shows that both TRAP‐positive and TRAP‐negative de novo GBM have elongated telomeres, further supports that telomerase activity is present in all de novo GBM. Correlations with tumor size and extent of necrosis suggest that hTERT reactivation is an early event in GBM development and that telomerase activity may be lost in subpopulations of neoplastic cells during tumor progression. Finally, ISH analysis of hTERT mRNA seems to provide a prognostic parameter for primary de novo GBM. Int. J. Cancer 88:895–901, 2000.

Surgical treatment of primary supratentorial intracerebral hemorrhage in stuporous and comatose patients.

Abstract Primary supratentorial intracerebral hemorrhage can be considered as one of the most devastating forms of cerebrovascular disease. Reduction in intracranial volume buffering capacity and severe intracranial pressure are the most important factors related to a poor prognosis in cases with huge hematoma and altered state of consciousness. The role of surgery in the management of such cases appears still controversial. Nevertheless, it is conceivable that some cases with poor natural outcome might benefit from surgical evacuation. Fifty patients with altered state of consciousness and primary supratentorial intracerebral hemorrhage ranging from 24 to 75 ml were submitted to surgical evacuation of the hematoma. The decision to operate was based on the presence of signs indicating an oncoming severe intracranial hypertension. In 15 patients, in whom a progression in brain swelling was expected to occur after the hematoma evacuation, a decompressive craniectomy, associated with dural enlargement, was performed after the initial surgical procedure. The overall analysis of the clinical results at one year after surgery showed 40% of complete recovery and 38% of improvement. A significant statistical correlation was found between outcome and pre-operative neurological status. The association of decompressive craniectomy and dural enlargement to hematoma evacuation, proved very useful in a group of severely compromised patients. Surgical treatment of patients with primary supratentorial intracerebral hemorrhage and altered state of consciousness can have a positive role, in selected cases, by minimizing the lifethreatening progression of intracranial hypertension. [Neurol 2002; 24: 54-60]

Effects of Testosterone on Antioxidant Systems in Male Secondary Hypogonadism

Oxidative stress is involved both in metabolic syndrome and male infertility. Hypogonadism is also associated with increased risk for cardiovascular disease. To investigate the role of gonadal steroids in systemic antioxidant regulation, we determined plasma CoenzymeQ(10) (CoQ(10)) and total antioxidant capacity (TAC) in postsurgical hypopituitaric patients. Twenty-six patients aged 28-55 years were studied 6-12 months after surgery. CoQ(10) levels were measured by high-performance liquid chromatography and TAC by spectroscopy with the use of the mioglobin-H(2)O(2) system, which, in interacting with chromogen 2,2(I)-azinobis-(3-ethylbenzothiazoline-6-sulfonate), generates a radical after a latency time (LAG) that is proportional to antioxidant content. Sixteen patients presented low testosterone values; in 10 patients hypogonadism was isolated, and in 6 patients hypothyroidism also was present. CoQ(10) levels were significantly lower in isolated hypogonadism than in normogonadism. Testosterone treatment, performed in those patients with isolated hypogonadism, induced a significant enhancement both in CoQ(10) level and LAG. CoQ(10) and LAG values correlated significantly, suggesting an interrelationship between different antioxidants. Our data suggest that hypogonadism could represent a condition of oxidative stress, in turn related with augmented cardiovascular risk.

Factors predicting pasireotide responsiveness in somatotroph pituitary adenomas resistant to first generation somatostatin analogues: an immunohistochemical study

AIMnTo gather data regarding factors predicting responsiveness to pasireotide in acromegaly.nnnPATIENTS AND METHODSnSSTR2a, SSTR3, SSTR5, AIP, Ki-67 and the adenoma subtype were evaluated in somatotroph adenomas from 39 patients treated post-operatively with somatostatin analogues (SSAs). A standardized SSTR scoring system was applied (scores 0-3). All patients received first-generation SSAs, and 11 resistant patients were subsequently treated with pasireotide LAR.nnnRESULTSnNone of the patients with negative or cytoplasmic-only SSTR2a expression (scores 0-1) were responsive to first-generation SSAs, as opposed to 20% (score 2) and 50% of patients with a score of 3 (P=0.04). None of the patients with an SSTR5 score of 0-1 were responsive to pasireotide, as opposed to 5/7 cases with a score of 2 or 3 (P=0.02). SSTR3 expression did not influence first-generation SSAs or pasireotide responsiveness. Tumours with low AIP were resistant to first-generation SSAs (100 vs 60%; P=0.02), while they had similar responsiveness to pasireotide compared to tumours with conserved AIP expression (50 vs 40%; P=0.74). Tumours with low AIP displayed reduced SSTR2 (SSTR2a scores 0-1 44.4 vs 6.7%; P=0.006) while no difference was seen in SSTR5 (SSTR5 scores 0-1 33.3 vs 23.3%; P=0.55). Sparsely granulated adenomas responded better to pasireotide compared to densely granulated ones (80 vs 16.7%; P=0.04).nnnCONCLUSIONnThe expression of SSTR5 might predict responsiveness to pasireotide in acromegaly. AIP deficient and sparsely granulated adenomas may benefit from pasireotide treatment. These results need to be confirmed in larger series of pasireotide-treated patients.