Guanine nucleotide exchange factor Dock7 mediates HGF-induced glioblastoma cell invasion via Rac activation.

BACKGROUND: Glioblastoma multiforme (GBM), a highly invasive primary brain tumour, remains an incurable disease. Rho GTPases and their activators, guanine nucleotide exchange factors (GEFs), have central roles in GBM invasion. Anti-angiogenic therapies may stimulate GBM invasion via HGF/c-Met signalling. We aim to identify mediators of HGF-induced GBM invasion that may represent targets in a combination anti-angiogenic/anti-invasion therapeutic paradigm. METHODS: Guanine nucleotide exchange factor expression was measured by microarray analysis and western blotting. Specific depletion of proteins was accomplished using siRNA. Cell invasion was determined using matrigel and brain slice assays. Cell proliferation and survival were monitored using sulforhodamine B and colony formation assays. Guanine nucleotide exchange factor and GTPase activities were determined using specific affinity precipitation assays. RESULTS: We found that expression of Dock7, a GEF, is elevated in human GBM tissue in comparison with non-neoplastic brain. We showed that Dock7 mediates serum- and HGF-induced glioblastoma cell invasion. We also showed that Dock7 co-immunoprecipitates with c-Met and that this interaction is enhanced upon HGF stimulation in a manner that is dependent on the adaptor protein Gab1. Dock7 and Gab1 also co-immunoprecipitate in an HGF-dependent manner. Furthermore, Gab1 is required for HGF-induced Dock7 and Rac1 activation and glioblastoma cell invasion. CONCLUSIONS: Dock7 mediates HGF-induced GBM invasion. Targeting Dock7 in GBM may inhibit c-MET-mediated invasion in tumours treated with anti-angiogenic regimens.

Binding of 14-3-3 proteins to the protein kinase Raf and effects on its activation.

To identify proteins that may participate in the activation of the protein kinase Raf, proteins that interact with Raf were selected in a two-hybrid screen. Two members of the 14-3-3 protein family were isolated that interacted with both the amino terminal regulatory regions of Raf and the kinase domain of Raf, but did not compete with the guanine nucleotide-binding protein Ras for binding to Raf. 14-3-3 proteins associated with Raf in mammalian cells and accompanied Raf to the membrane in the presence of activated Ras. In yeast cells expressing Raf and MEK, mammalian 14-3-3 beta or 14-3-3 zeta activated Raf to a similar extent as did expression of Ras. Therefore, 14-3-3 proteins may participate in or be required for the regulation of Raf function. These findings suggest a role for 14-3-3 proteins in Raf-mediated signal transduction.

RSR1, a ras-like gene homologous to Krev-1 (smg21A/rap1A): role in the development of cell polarity and interactions with the Ras pathway in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae ras-like gene RSR1 is particularly closely related to the mammalian gene Krev-1 (also known as smg21A and rap1A). RSR1 was originally isolated as a multicopy suppressor of a cdc24 mutation, which causes an inability to bud or establish cell polarity. Deletion of RSR1 itself does not affect growth but causes a randomization of bud position. We have now constructed mutant alleles of RSR1 encoding proteins with substitutions of Val for Gly at position 12 (analogous to constitutively activated Ras proteins) or Asn for Lys at position 16 (analogous to a dominant-negative Ras protein). rsr1Val-12 could not restore a normal budding pattern to an rsr1 deletion strain but could suppress a cdc24 mutation when overexpressed. rsr1Asn-16 could randomize the budding pattern of a wild-type strain even in low copy number but was not lethal even in high copy number. These and other results suggest that Rsr1p functions only in bud site selection and not in subsequent events of polarity establishment and bud formation, that this function involves a cycling between GTP-bound and GDP-bound forms of the protein, and that the suppression of cdc24 involves direct interaction between Rsr1p[GTP] and Cdc24p. Functional homology between Rsr1p and Krev-1 p21 was suggested by the observations that expression of the latter protein in yeast cells could both suppress a cdc24 mutation and randomize the budding pattern of wild-type cells. As Krev-1 overexpression can suppress ras-induced transformation of mammalian cells, we looked for effects of RSR1 on the S. cerevisiae Ras pathway. Although no suppression of the activated RAS2Val-19 allele was observed, overexpression of rsr1Val-12 suppressed the lethality of strains lacking RAS gene function, apparently through a direct activation of adenyl cyclase. This interaction of Rsr1p with the effector of Ras in S. cerevisiae suggests that Krev-1 may revert ras-induced transformation of mammalian cells by affecting the interaction of ras p21 with its effector.

Raf-1 interferes with Ras and Rap1A effector functions in yeast.

Raf-1 is a serine/threonine kinase that acts downstream of Ras in mitogenic signal transduction pathways, but the mechanism by which Ras transmits signals to Raf-1 is not known. We have examined the interaction between Raf-1 and human H-ras in three different systems that utilize H-ras-induced phenotypes in Saccharomyces cerevisiae. In each system, the effects of H-ras depend on guanosine triphosphate and appear to be mediated through the H-ras effector binding region. H-ras effector function was blocked in each case by expression of the N-terminal regulatory domain of Raf-1. These inhibitory effects did not require the Raf-1 kinase domain. Raf-1 also blocked Rap1A effector function in S. cerevisiae. Raf-1, therefore, appears to interact with H-Ras and Rap1A in these in vivo systems with properties that suggest it is an immediate downstream effector.

Radiation dose intensification in pre-operative chemo-radiotherapy for locally advanced rectal cancer.

BACKGROUND: To assess the role of radiation dose intensification with simultaneous integrated boost guided by 18-FDG-PET/CT in pre-operative chemo-radiotherapy (ChT-RT) for locally advanced rectal cancer. METHODS: A prospective study was approved by the Internal Review Board. Inclusion criteria were: age >18 years old, World Health Organization performance status of 0-1, locally advanced histologically proven adenocarcinoma of the rectum within 10 cm of the anal verge, signed specific informed consent. High-dose volumes were defined including the hyper-metabolic areas of 18-FDG-PET/CT of primary tumor and the corresponding mesorectum and/or pelvic nodes with at least a standardized uptake values (SUV) of 5. A dose of 60 Gy/30 fractions was delivered. A total dose of 54 Gy/30 fractions was delivered to prophylactic areas. Capecitabine was administered concomitantly with RT for a dose of 825 mg/mq twice daily for 5 days/every week. RESULTS: Between September 2011 and July 2015 fortypatients were recruited. At the time of the analysis, median follow up was 20 months (range 5-51). The median interval from the end of ChT-RT to surgery was 9 weeks (range 8-12). Thirty-seven patients (92.5 %) were submitted to sphincter preservation. Tumor Regression Grade (Mandard scale) was recorded as follows: grade 1 in 7 (17.5 %), grade 2 in 17 (42.5 %), grade 3 in 15 (37.5 %) and grade 4 in 1 (2.5 %). Post-surgical circumferential resection margin was negative in all patients. A tumor downstaging was reported in 62.5 % (95 % CI: 0.78-0.47). A nodes downstaging was registered in 85 % (95 % CI: 0.55-0.25). 18-FDG-PET/CT was not able to predict pCR. No correlation was found between pre-treatment SUV-max values and pCR. A metabolic tumor volume >127 cc was related to ypT ≥2 (p 0.01). Patients with TRG >2 had higher tumor lesion glycolysis values (p 0.05). CONCLUSION: Preliminary results did not confirm some advantages in terms of primary tumor downstaging/downsizing compared to conventional schedules reported in historical series. The role of 18-FDG-PET/CT in neoadjuvant rectal cancer management needs to be confirmed in further investigations. Long terms results are necessary.

Applying radiobiological plan ranking methodology to VMAT prostate SBRT.

The impact of a rectal spacer and an increased near maximum target dose in VMAT prostate SBRT is studied. For a group of 11 patients (35Gy-in-five-fractions VMAT prostate SBRT) a set of 4 plans were generated, namely two VMAT plans, with D2%⩽37.5Gy (Hom) and with D2%⩽40.2Gy (Het), were created for each of two CT scans taken before (NoSpc) and after (Spc) transperineal spacer insertion. Consequently the methodology for parameter invariant TCP (tumor control probability) plan ranking was applied for comparison of the plans in terms of tumor control. NTCPs (normal tissue complication probabilities) were calculated for rectum and bladder using Lyman's model. For all 11 patients the TCP plan ranking has shown that the Het plans would perform considerably better in TCP terms than the Hom ones. The plans without rectal spacer were ranked worse compared to those with rectal spacer except for one set of Hom plans. The calculated NTCPs for rectum produced by the Het plans were quite similar to the NTCPs of the Hom ones. The rectal NTCPs of the Hom Spc plans were always lower than the NTCPs of the Hom NoSpc plans. The NTCP values for bladder were extremely low in all cases. The use of rectal spacer leads in general to lower risk of rectal complications, as expected, and even to better tumor control. Plans with increased near maximum target dose (D2%⩽40.2Gy) are expected to perform much better in terms of tumor control than those with D2%⩽37.5Gy.

Cachexia induces head and neck changes in locally advanced oropharyngeal carcinoma during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy.

BACKGROUND/OBJECTIVES: Cancer cachexia is a syndrome characterized by weight loss (WL) and sarcopenia. Aim of the study was to assess the impact of cachexia on head and neck changes during definitive cisplatin and image-guided volumetric-modulated arc radiation therapy in a series of locally advanced oropharyngeal cancer. SUBJECTS/METHODS: Volume variations of sternocleidomastoid muscle (SCM) were considered as surrogate of muscle changes related to sarcopenia. Two head and neck diameters, encompassing the cranial limits of II and III nodal levels (defined as 'head diameter' and 'neck diameter', respectively), were measured. All parameters were defined retrospectively by means of on-board cone beam computed tomography images at 1-8th to 15-22th and at last fraction (fx) of radiotherapy (RT). Cachexia was defined as WL >5% during treatment. Analysis was conducted correlating the parameter changes with three WL ranges: <5, 5-9 and>10%. RESULTS: Thirty patients were evaluated. One hundred and fifty contoured SCMs and three hundred diameters were collected. Median WL was 6.5% (range, 0-16%). The most significant SCM shrinkage was recorded at 15th fx (mean 1.6 cc) related to WL 5-9% and WL >10% (P 0.001). For 'head diameter', the peak reduction was recorded at the 15th fx (mean 8 mm), statistically correlated to WL >10% (P 0.001). The peak reduction in 'neck diameter' was registered at the 22th fx (mean 6 mm), with a gradual reduction until the end of treatment for WL >5%. CONCLUSIONS: In a homogeneous cohort of patients, present study quantified the impact of cachexia on head and neck changes. Present data could provide adaptive RT implications for further investigations.

The MAP3K ZAK, a novel modulator of ERK-dependent migration, is upregulated in colorectal cancer.

Often described as a mediator of cell cycle arrest or as a pro-apoptotic factor in stressful conditions, the MAP3K ZAK (Sterile alpha motif and leucine zipper-containing kinase) has also been proven to positively regulate epidermal growth factor receptor (EGFR) and WNT signaling pathways, cancer cell proliferation and cellular neoplastic transformation. Here, we show that both isoforms of ZAK, ZAK-α and ZAK-ß are key factors in cancer cell migration. While ZAK depletion reduced cell motility of HeLa and HCT116 cells, its overexpression triggered the activation of all three mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK), c-JUN N-terminal kinase (JNK) and p38, as well as an increase in cell motion. On the contrary, the kinase-dead mutants, ZAK-α K45M and ZAK-ß K45M, were not able to provoke such events, and instead exerted a dominant-negative effect on MAPK activation and cell migration. Pharmacological inhibition of ZAK by nilotinib, preventing ZAK-autophosphorylation and thereby auto-activation, led to the same results. Activated by epidermal growth factor (EGF), we further showed that ZAK constitutes an essential element of the EGF/ERK-dependent cell migration pathway. Using public transcriptomic databases and tissue microarrays, we finally established that, as strong factors of the EGFR signaling pathway, ZAK-α and/or ZAK-ß transcripts and protein(s) are frequently upregulated in colorectal adenoma and carcinoma patients. Notably, gene set enrichment analysis disclosed a significant correlation between ZAK+ colorectal premalignant lesions and gene sets belonging to the MAPK/ERK and motility-related signaling pathways of the reactome database, strongly suggesting that ZAK induces such pro-tumoral reaction cascades in human cancers.

The impact of prostate gland dimension in genitourinary toxicity after definitive prostate cancer treatment with moderate hypofractionation and volumetric modulated arc radiation therapy.

PURPOSE: To analyze clinical-dosimetric predictors of genitourinary (GU) toxicity in a cohort of prostate cancer (PC) patients treated with moderate hypofractionation and simultaneous integrated boost (SIB) using volumetric modulated arc therapy (VMAT) technique. MATERIALS AND METHODS: 60 patients were selected. Patients were stratified into low (43 %), intermediate (30 %) and high-risk (27 %) groups. Low-risk patients received 73.5 Gy to PTV1; intermediate-risk received 73.5 Gy to PTV1 and 60 Gy to PTV2; high-risk received 73.5 Gy to PTV1, 60 Gy to PTV2, and 54 Gy to PTV3. All patients were treated in 30 fractions. Androgen deprivation therapy (ADT) was prescribed upfront in intermediate and high-risk categories. Toxicity was scored according to Common Terminology Criteria for Adverse Events v4.0 scoring system. RESULTS: Median follow-up was 30 months (range 16-36 months). GU acute toxicity was recorded as followS: G0 = 16/60 (27 %), G1 = 18/60 (30 %); G2 = 26/60 (43 %). GU late toxicity was recorded as follows: G0 = 20/60 (34 %); G1 = 29/60 (48 %); G2 = 11/56 (18 %). The risk of acute G2 GU toxicity was three times higher for prostate volume ≥80 cc. In 60 % of the patients with a prostate volume ≥80 cc, the first 3 weeks are at particular risk for toxicity onset. In the late setting, no statistical significance was found between GU toxicity and prostate gland dimension. CONCLUSION: Prostate volume ≥80 cc resulted a predictive factor of acute G2 GU toxicity, in moderate hypofractionation and volumetric modulated arc radiation therapy for definitive PC.

Intensity modulated radiation therapy with simultaneous integrated boost in early breast cancer irradiation. Report of feasibility and preliminary toxicity.

PURPOSE: To investigate the feasibility and tolerance in the use of adjuvant intensity modulated radiation therapy (IMRT) and simultaneous integrated boost in patients with a diagnosis of breast cancer after breast-conserving surgery. PATIENTS AND METHODS: Between September 2011 to February 2013, 112 women with a diagnosis of early breast cancer (T1-2, N0-1, M0) were treated with IMRT and simultaneous integrated boost after breast-conserving surgery in our institution. A dose of 50Gy in 25 fractions was prescribed to the whole breast and an additional dose of radiation was prescribed on the tumour bed. A dose prescription of 60Gy in 25 fractions to the tumour bed was used in patients with negative margins after surgery, whereas if the margins were close (<1mm) or positive (without a new surgical resection) a dose of 64Gy was prescribed. All patients were followed with periodic clinical evaluation. Acute and late toxicity were scored using the EORTC/RTOG radiation morbidity score system. Both patient and physician recorded cosmetic outcome evaluation with a subjective judgment scale at the time of scheduled follow-up. RESULTS: The median follow-up was 28 months (range 24-40 months). The acute skin grade toxicity during the treatment was grade 0 in 8 patients (7%), grade 1 in 80 (72%), grade 2 in 24 cases (21%). No grade 3 or higher acute skin toxicity was observed. At 12 months, skin toxicity was grade 0 in 78 patients (70%), grade 1 in 34 patients (30%). No toxicity grade 2 or higher was registered. At 24 months, skin toxicity was grade 0 in 79 patients (71%), grade 1 in 33 patients (29%). No case of grade 2 toxicity or higher was registered. The pretreatment variables correlated with skin grade 2 acute toxicity were adjuvant chemotherapy (P=0.01) and breast volume ≥700cm(3) (P=0.001). Patients with an acute skin toxicity grade 2 had a higher probability to develop late skin toxicity (P<0.0001). In the 98% of cases, patients were judged to have a good or excellent cosmetic outcome. The 2-year-overall survival and 2-year-local control were 100%. CONCLUSION: These data support the feasibility and safety of IMRT with simultaneous integrated boost in patients with a diagnosis of early breast cancer following breast-conserving surgery with acceptable acute and late treatment-related toxicity. A longer follow-up is needed to define the efficacy on outcomes.

Bile secretion and liver microsomal mixed function oxidase system in mice with griseofulvin-induced hepatic protoporphyria.

Administration of 2.5% griseofulvin in the diet to male CD1 mice produced protoporphyria and cholestasis. Protoporphyria became evident as early as after 10 days of treatment, whereas cholestasis, expressed in terms of total bile flow reduction, developed only after 45 days of griseofulvin. Bile flow impairment was due both to the length of treatment and to the severity of liver protoporphyria. Griseofulvin administration was also associated with a significant modification of the relative amounts of hepatic microsomal cytochromes P-450 and b5, a loss in concentration/mg of protein of cytochrome P-450 and a concomitant increase of b5. Despite these changes, the activity of aniline hydroxylase expressed per mg of microsomal protein, assessed in vitro, was not modified.

Different susceptibility of mouse tissues to porphyrogenic effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

The porphyrogenic effect of chronic administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (25 micrograms/kg/week) to male C57BL/6 mice was evaluated through quantitative and qualitative analysis of the porphyrins accumulated and of porphyrinogen carboxylase activity in liver, kidney, spleen, brain and erythrocytes. The liver was the principal site of action, both for porphyrin accumulation and for enzyme inhibition, with kidney next, whereas brain and erythrocytes were unaffected. In the spleen, despite unchanged formation of total products of uroporphyrinogen III decarboxylation, both an increase and a decrease of coproporphyrinogen formation were observed, the decrease being concomitant with a higher accumulation of tissue porphyrins. When a response to TCDD was found, the formation of the products of decarboxylaction of uroporphyrinogen III were affected to different extents. The pattern of enzyme inhibition paralleled data reported in the literature regarding tissue distribution of TCDD and indicated that TCDD porphyria is a suitable experimental model for the human 'sporadic' type of porphyria cutanea tarda (PCT).

In vitro inhibitory effect on porphyrinogen carboxylyase of liver extracts from TCDD treated mice.

Marked inhibition of porphyrinogen carboxylyase was produced in vitro by cytosol fractions, deproteinized and free of porphyrins, obtained from livers of mice made porphyric by 9 weeks i.p. treatment with 25 micrograms/kg/week of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Inhibition was proportional to the amount of the fraction added, was increased by preincubation in the absence of the substrate and, once established, could not be reversed by dialysis. TCDD itself, added to the control enzyme in the incubation mixture, did not affect enzyme activity up to a concentration of 77 nM, which is 10 times higher than the liver TCDD concentration found after in vivo TCDD treatment.

Clinical evaluation of thallium-201 single photon emission computed tomography in equivocal neuroradiological supratentorial lesions.

BACKGROUND: We performed cerebral 201Tl SPECT study on 38 presurgical patients with equivocal neuroradiological supratentorial lesions to detect differences in 201Tl uptake index between tumor/non-tumor and high-grade/low-grade samples. METHODS: Authors identified 38 cases with presurgical equivocal neuroradiological supratentorial mass lesions. All cases were submitted to histological confirmation of the lesion by biopsy, sub-total or gross-total removal of the tumor. Between 23 patients suffering from gliomas, 13 were histologically classified as being of low-grade malignant tumors and 10 were classified as being of high-grade malignancy. Fifteen non-tumor histopathological specimens were also detected. The 201Tl index was defined as the ratio of average counts per pixel in the lesion to these in the opposite region. Analysis of variance (ANOVA) and unpaired Student's OtO-test statistical methods were applied. Actuarial survival time from the date of diagnosis was calculated using the Kaplan-Meier method. Follow-up evaluation and survival time were obtained through referring physicians. Cerebral CT or MR images were obtained every three months after discharged, or more often if indicated. RESULTS: Results showed that the 201Tl uptake index ranged from 1.10 to 3.00 in the tumors lesions (mean+/-SD: 1.68+/-0.51) and from 0.80 to 1.40 in the non-tumors lesions (mean+/-SD: 1.07+/-0.17), (alpha < 0.0006 percent;). The 201Tl uptake index ranged from 1.10 to 2.30 in 13 patients with low-grade tumors (mean+/-SD: 1.45+/-0.34) and from 1.30 to 3.00 in 10 patients with high-grade tumors (mean+/-SD: 1.98+/-0.55), (alpha < 0.5 percent;). CONCLUSIONS: Our results demonstrate the clinical utility of 201Tl brain SPECT to differentiate equivocal neuroradiological supratentorial lesions and to correlate relationship between preoperative diagnosis, histological tumor grade and prognosis.

[Cardiac and renal sodium-modulating hormones in juvenile arterial hypertension. The physiopathological aspects and therapeutic results of a trial at the Policlinico Militare Celio in Rome]. / Ormoni sodiomodulanti cardiaci e renali nell'ipertensione arteriosa giovanile. Considerazioni fisiopatologiche e terapeutiche derivate da una esperienza condotta nel Policlinico Militare Celio di Roma.

Sodium balance plays a primary role in blood pressure regulation. Atrial natriuretic peptide, a recently discovered natriuretic substance, seems to participate in renal sodium handling, but its behavior in essential hypertension has not been fully defined. In our study, to avoid the "contamination" of factors other than hypertension, we evaluated the plasma levels of atrial natriuretic peptide in young men at military draft age. Our main results showed that plasma atrial natriuretic peptide levels are higher in young hypertensives with low plasma renin activity and low urinary excretion of active kallikrein. The influence of a positive genetic background for essential hypertension on plasma atrial natriuretic peptide levels was also investigated. Our data showed slightly elevated levels of the atrial hormone in young normotensives with a family history of hypertension.

Dose-volume-related dysphagia after constrictor muscles definition in head and neck cancer intensity-modulated radiation treatment.

OBJECTIVE: Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM). METHODS: Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logistic regression. RESULTS: An increasing risk to develop acute dysphagia was observed when constraints to the middle PCs were not respected [mean dose (Dmean) ≥50 Gy, maximum dose (Dmax) >60 Gy, V50 >70% with a p = 0.05]. The superior PC was not correlated with acute toxicity but only with late dysphagia. The inferior PC was not correlated with dysphagia; for the CM only, Dmax >60 Gy was correlated with acute dysphagia ≥ grade 2. CONCLUSION: According to our analysis, the superior PC has a major role, being correlated with dysphagia at 3 and 6 months after treatments; the middle PC maintains this correlation only at 3 months from the beginning of radiotherapy, but it does not have influence on late dysphagia. The inferior PC and CM have a minimum impact on swallowing symptoms. ADVANCES IN KNOWLEDGE: We used recent guidelines to define dose constraints of the PCs and CM. Two results emerge in the present analysis: the superior PC influences late dysphagia, while the middle PC influences acute dysphagia.