In vivo effects of rosiglitazone in a human neuroblastoma xenograft.

BACKGROUND: Neuroblastoma (NB) is the most common extra-cranial solid tumour in infants. Unfortunately, most children present with advanced disease and have a poor prognosis. There is in vitro evidence that the peroxisome proliferator-activated receptor gamma (PPARgamma) might be a target for pharmacological intervention in NB. We have previously demonstrated that the PPARgamma agonist rosiglitazone (RGZ) exerts strong anti-tumoural effects in the human NB cell line, SK-N-AS. The aim of this study was to evaluate whether RGZ maintains its anti-tumoural effects against SK-N-AS NB cells in vivo. METHODS AND RESULTS: For this purpose, tumour cells were subcutaneously implanted in nude mice, and RGZ (150 mg kg(-1)) was administered by gavage daily for 4 weeks. At the end of treatment, a significant tumour weight inhibition (70%) was observed in RGZ-treated mice compared with control mice. The inhibition of tumour growth was supported by a strong anti-angiogenic activity, as assessed by CD-31 immunostaining in tumour samples. The number of apoptotic cells, as determined by cleaved caspase-3 immunostaining, seemed lower in RGZ-treated animals at the end of the treatment period than in control mice, likely because of the large tumour size observed in the latter group. CONCLUSIONS: To our knowledge, this is the first demonstration that RGZ effectively inhibits tumour growth in a human NB xenograft and our results suggest that PPARgamma agonists may have a role in anti-tumoural strategies against NB.

Expression of Id helix-loop-helix proteins in colorectal adenocarcinoma correlates with p53 expression and mitotic index.

Id helix-loop-helix (HLH) proteins function as regulators of cell growth and differentiation and when overexpressed can induce malignant transformation. In a series of 34 cases of primary human colorectal adenocarcinoma, immunoreactivity for Id1, Id2, and Id3 was found to be significantly elevated in tumor compared with normal mucosa (P = 0.001 for Id1 and Id2; P = 0.002 for Id3). No elevation of Id expression was observed in 17 cases of adenoma. Expression of Id1 and to a lesser extent of Id2 was correlated with mitotic index (P = 0.005 for Id1; P = 0.042 for Id2) in human adenocarcinomas, and expression of all three Id proteins was correlated with p53 immunoreactivity (a marker of mutational 'inactivation' of p53 function; P = 0.002 for Id1; P = 0.006 for Id2; P = 0.016 for Id3). In normal intestinal mucosa of p53-null mice and in spontaneous tumors arising in Min+/- mice, expression of all three Id proteins was also found to be up-regulated. Antisense oligonucleotide blockade of Id protein expression inhibited the proliferation of human adenocarcinoma cells. Enforced, ectopic expression of the E47 basic HLH (bHLH) protein in human adenocarcinoma cell lines efficiently sequestered endogenous Id proteins as Id-bHLH heterodimers, as shown by coimmunoprecipitation and subcellular colocalization studies. This led to growth arrest of the cells. Enforced overexpression of a mutant E47 protein, deficient in transactivation and DNA binding function, also partially inhibited cell growth. Taken together, these data imply that deregulated expression of Id proteins in colorectal adenocarcinoma arises at least in part as a consequence of loss of p53 function and contributes to the uncontrolled proliferation of tumor cells in colorectal cancer.

Nitroxides and malignant human tissues: electron spin resonance in colorectal neoplastic and healthy tissues.

Healthy and neoplastic colorectal human tissues of as many as 12 patients have been studied, immediately after surgery, by electron spin resonance (ESR) of stable nitroxides at physiological temperature. Cells were maintained in a living state using the McCoy's 5A culture medium. The very low concentration changes of hydrophilic and lipophilic nitroxides allowed us to establish that the response to the oxidative stress induced by the occurrence of nitroxides in healthy and tumor cells was very weak, thus suggesting these compounds are good candidates for contrast enhancement agents in magnetic resonance imaging of colorectal tumor. The analysis of the computed ESR line shape of lipophilic nitroxides in both healthy and malignant cells of the same patient agreed for an unmodified physical status of the membranes where they were mainly localized. The results reported here proved that the comparison between ESR results must be made in tissues from the same patient and that the physical status of the membranes depended more on the patient history than on changes in the colorectal cell membrane fluidity induced by the neoplastic process.

HERG potassium channels are constitutively expressed in primary human acute myeloid leukemias and regulate cell proliferation of normal and leukemic hemopoietic progenitors.

An important target in the understanding of the pathogenesis of acute myeloid leukemias (AML) relies on deciphering the molecular features of normal and leukemic hemopoietic progenitors. In particular, the analysis of the mechanisms involved in the regulation of cell proliferation is decisive for the establishment of new targeted therapies. To gain further insight into this topic we report herein a novel approach by analyzing the role of HERG K(+) channels in the regulation of hemopoietic cell proliferation. These channels, encoded by the human ether-a-gò-gò-related gene (herg), belong to a family of K(+) channels, whose role in oncogenesis has been recently demonstrated. We report here that herg is switched off in normal peripheral blood mononuclear cells (PBMNC) as well as in circulating CD34(+) cells, however, it is rapidly turned on in the latter upon induction of the mitotic cycle. Moreover, hergappears to be constitutively activated in leukemic cell lines as well as in the majority of circulating blasts from primary AML. Evidence is also provided that HERG channel activity regulates cell proliferation in stimulated CD34(+) as well as in blast cells from AML patients. These results open new perspectives on the pathogenetic role of HERG K(+) channels in leukemias.

The effects of irradiation at different times of the day on rat intestinal goblet cells.

Quantitative changes in jejunal goblet cells were studied in control and whole body irradiated rats using PAS-Alcian blue staining of crypt sections. A circadian dependence was observed when control animals were killed at different times during the light/dark cycle. Irradiation with 3 Gy produced a 2-3-fold increase within 36 h in goblet cells relative to controls, followed by a reduction to very low levels. There was a return to pre-treatment levels later than was observed for the columnar cells. The present results on the pattern of response of goblet cells and those of brush border enzyme activity are consistent with the hypothesis that ionizing radiation can influence differentiation. In fact during the first hours after irradiation an early induction of differentiation is evident while during the early repopulation phase columnar cells prevailed relative to the goblet cells. Only at later times were normal differentiation patterns seen. Groups of animals exposed to the same dose of radiation at different times of the day showed similar general patterns of behaviour even if the group irradiated at midnight showed a more marked and longer lasting injury.

3H-thymidine labelling index (TLI) as a marker of tumour growth heterogeneity: evaluation in human solid carcinomas.

Many studies deal with the analysis of cell kinetic, cytogenetic, biochemical and molecular cell biology parameters to identify prognostic factors relating to tumour growth but all methods use only a small part of the total tumour mass. This study is devoted to the analysis of the heterogeneity of the growth of human solid tumours assaying proliferative activity by means of 3H-thymidine labelling index (TLI) in a fixed number of samples collected in different areas of the lesion (larynx and colon cancers), or in different lesions of the same subject (breast and bladder cancers). Each sample (at the macroscopic level) was divided into small fragments (at the microscopic level) and proliferative activity was determined. The analysis of variance for hierarchical designs demonstrated that in all cases a high component of the variance is attributable to the subjects and to the fragments whereas the variance attributable to the different areas is very low. The heterogeneity of proliferative activity displays a higher focal variability among the fragments (microscopic level) compared with that among areas (macroscopic level) within subjects, provided an adequate number of fragments and cells are counted. In multiple synchronous carcinoma of the bladder the wide variability of proliferation among the single lesions demonstrated that it is necessary to analyse all the tumours in a subject because each one is characterized by a different cell growth potential.

Biological properties associated with the enhanced lung-colonizing potential in a B16 murine melanoma line grown in a medium conditioned by syngeneic Corynebacterium parvum-elicited macrophages.

A previous study by our laboratory showed that the peritoneal murine Corynebacterium parnum-elicited macrophages released into their growth medium an activity which enhanced the ability of B16-F10 melanoma cells to form experimental metastases in the lung of syngeneic mice. In the present study, we used a clone of B16-F10 line (F10-M3 cells) to investigate whether the increase in lung-colonizing potential due to the pro-clonogenic activity released by C. parvum-elicited macrophages was associated with biological properties characteristic of a metastatic phenotype. We have found that the pulmonary retention, growth rate in lung parenchyma, invasiveness through Matrigel, adhesiveness to IL-1-activated endothelium and MHC class I expression were increased in F10-M3 cells stimulated by the macrophage pro-clonogenic activity. By using an in vitro experimental protocol, the enhancement of lung-colonizing potential in the stimulated melanoma cells turned out to be a transient phenomenon as was the increase of invasiveness through Matrigel and the higher expression of MHC class I antigens. In conclusion, the melanoma cells stimulated by the pro-clonogenic activity released by C. parvum-elicited macrophages showed changes in biological parameters which are relevant to metastatic diffusion. These changes appeared as a temporary phenomenon which sustains the view that the metastatic phenotype represents a transient biological character influenced by host factors.

Brush border intestinal enzymes after multiple daily fractionation.

The modifications in brush border enzyme activity of the epithelial cell of the small intestine were studied after multiple daily fractionation (MDF) of 3 Gy X and 3 Gy X 2 X 2 (12 h split). Disaccharase and dipeptidase activities changed in the same way after irradiation. The results show that both total doses caused the three known phases of increase, decrease, and a return to normal. With MDF, activity at the end of irradiation was similar to or greater than that of controls and remained higher longer than a single dose of 8 Gy. However, the return to normal occurred sooner than after a single dose of 8 Gy. After 11 days, circadian oscillations of brush border enzyme activity appeared similar to those of controls in many segments of the intestine, reaching the highest activity during the night and the lowest in the afternoon.

Cell kinetics in rat small intestine after exposure to 3 Gy of gamma-rays at different times of the day.

Qualitative and quantitative morphological changes in rat jejunum were studied after a whole-body exposure to 3 Gy of gamma rays. Four groups of animals were irradiated at different times of the day, namely midnight, 06.00, 12.00 and 18.00 hours. The number of epithelial cells, labelling and mitotic indices were evaluated in crypt sections and the spatial distribution of S-phase cells was determined. At 12 h after irradiation a marked reduction was observed in all parameters, but the proliferative activity was restored quickly and at 36 h after irradiation the values were significantly higher than the controls. The frequency distribution of labelled cells at different positions in the crypt was reduced at 12 h but a clear expansion of S phase cells to positions near to the crypt villus junction was observed during the recovery phase. The animals irradiated at different times of the day showed a similar general post-irradiation response in the number of cells along the side of the crypt, labelling and mitotic indices and in the distribution of S phase cells along the crypts. It is worth noting that the animals exposed at midnight had a distribution of S phase cells similar to controls at 72 h post-irradiation, i.e. earlier than the other groups.

Cell kinetics and biochemical parameters in breast cancer.

The study analyzes biochemical and cell kinetic parameters to characterize solid tumor growth in humans. The concentrations of polyamines, CEA, the thymidine labeling index (T.L.I.) and the mitotic index (M.I.) were determined on fragments of neoplastic tissue from 18 patients with breast carcinoma. Urinary polyamines were evaluated in the same patients. Two groups of patients were distinguished according to the median value of the with high T.L.I., M.I. and tissue polyamines were significantly higher than in the group with low T.L.I., whereas tissue CEA was lower, though in a not statistically significant way. Urinary polyamines showed no variations between groups. These preliminary results showed that T.L.I. levels were higher in patients who relapsed during a 4-year follow-up than in patients achieving complete remission and remaining disease free. Results concerning polyamine concentration showed that the tissue polyamine level in breast carcinoma indicated proliferative activity, but this does not seem to be valuable for current prognostic purposes.

Relationship between cytosol TPS, TPA and cell proliferation.

The serological tumor marker tissue polypeptide antigen (TPA) and the more recently identified tissue-specific polypeptide antigen (TPS) have been reported to be indicators of the proliferation rate of the tumor. In the present investigation we compared the cytosol level of the two markers with the proliferative activity of the tumor measured using the 3H-thymidine labelling index. The preliminary results presented here show that higher TLI is associated with lower cytosol levels of both TPA and TPS. TPA and TPS in the cytosol were significantly associated. These findings are in agreement with the previously demonstrated association between high TPA cytosol levels and better prognosis in breast cancer. Further studies are ongoing in order to: 1. confirm these findings in a larger patient series; 2. investigate any possible prognostic indication provided by TPS; 3. evaluate any possible biological meaning of the negative association between TPA/TPS and TLI in the cytosol of breast cancer.

Cell kinetics of melanocytes in common and dysplastic nevi and in primary and metastatic cutaneous melanoma.

The 3H-thymidine labelling (LI) and mitotic (MI) indexes were calculated in 29 cutaneous melanocytic lesions: 6 common nevi (CN), 11 dysplastic nevi, subclassified as nevi with architectural atypia (NAA = 4) and nevi with cyto-architectural atypia (NCAA = 7), 2 melanomas in situ (MIS), 4 invasive superficial spreading melanomas (IM) and 6 metastatic melanomas (MM). The LI mean values resulted to be: CN = 0.23%, NAA = 0.98%, NCAA = 1.79%, MIS = 5.75%, IM = 5.16%, MM = 3.80%. In CN, NAA, NCAA and MIS, these values were calculated at epidermal level; in IM and MM at dermal level. At dermal level, the LI mean values of CN, NAA and NCAA were: 0.20%, 0.20%, 0.23% respectively. The MI mean value was close to 0 in CN, NAA, NCAA, MIS; 0.18% in IM, 0.16% in MM. Confirming a low proliferative activity in CN and a high activity in melanomas (MIS, IM, MM), the results showed that dysplastic nevi (NAA, NCAA) had a proliferative activity intermediate between common nevi and melanomas. The lesions with melanocytic atypia (NCAA) resulted to have a higher proliferative activity than those without this histological feature (NAA).

Radiotherapy in the aged.

Radiation therapy fulfills all the requirements to be used with curative or palliative intent in nearly every case of cancer in the elderly. Radiotherapy is not associated with acute mortality in older persons and can permit organ and tissue preservation. The modern modalities to deliver radiotherapy treatment permit a large sparing of normal tissues. We need major information on proliferative activity of normal tissues and cancer in the elderly, on results according to stage of tumors, and on acute and late sequelae according to performance status of the patient. It is mandatory to perform prospective studies in order to work out protocols for oncologic treatments and specifically for radiotherapy, to treat adequately an increasing part of population.

Proliferative activity in normal colon mucosa and tumor tissue: clinical implications.

The study deals with the analysis of proliferative activity in colon carcinomas and adjacent normal appearing mucosa, evaluated with in vitro 3H-Thymidine and autoradiography. In the colonic mucosa no significant differences in 3H-Thymidine Labelling Index (TLI) were observed in relation to the distance of the sample from the neoplasia. The distribution of S-phase cells along the crypt length is low at the bottom, increases rapidly with a maximum within the lower 25% and decreases in the highest positions. When the proliferative activity is increased there is the possibility of expanding the proliferative compartment towards the luminal region of the crypt. The division of the crypt into 5 parts makes it possible to identify 2 different patterns: the first with a very high TLI in the lower fifth, then a sharp decrease and without labelled cells in the highest parts; the second with labelled cells present also in the luminal fifth. These 2 aspects are characteristic of specimens with the lowest and the highest TLI values respectively. The analysis of TLI in colo-rectal cancers shows that cell kinetics parameters are not related to clinical and histopathological features such as sex, age, Dukes and TNM stages and grade of differentiation.

Cell kinetics in breast cancer.

In breast cancer the study of prognostic factors has been well developed during last years and many biologic and biochemical parameters have been analyzed. Cell kinetics parameters demonstrated the capability to select patients with different risk of evolution of the neoplasia and in some cases treatment protocols are established by means of proliferation rate. The present study deals with the determination of Thymidine Labelling Index in breast tumors mostly T1-T2 with negative lymph nodes. Results demonstrated that the proliferative activity is higher in younger patients, in T2 cancers compared to T1, and in ductal infiltrating forms compared to the other more frequent histotypes. A significant correlation has been observed between TLI and nuclear grade. The preliminary analysis of the prognostic value of TLI has been two performed using an experimental cut off that is able to discriminate groups of patients with overall survival rate of 67% and 88%, depending on the different proliferative activity of the tumor.

A comparison of proliferation markers (BrdUrd, Ki-67, PCNA) determined at each cell position in the crypts of normal human colonic mucosa.

Samples of microscopically normal human sigmoid colon fixed in 70% ethanol from 15 patients who had received bromodeoxyuridine (BrdUrd) prior to surgery have been reanalyzed using a combination of proliferation markers. The specimens have been immunostained for proliferating cell nuclear antigen (PCNA) and after microwave treatment, they have been stained for BrdUrd and Ki-67. The 15 patients selected comprised 5 patients whose mucosa previously gave high BrdUrd labelling indices in the crypt, 5 that gave median values for BrdUrd labelling and 5 that gave low values for bromodeoxyuridine labelling on a previous analysis using tissue fixed in 70% ethanol and formal saline and using a different antibody (Potten et al., 1992). The relative levels of labelling at each cell position in the crypts has been compared using the 3 proliferation markers with the data being compared with the BrdUrd labelling as a standard labelling for S phase cells. One objective was to see whether all three proliferation markers discriminated equally well between the three groups of patient samples. The data show that the distinction between high, medium and low values seen with BrdUrd labelling was retained when Ki-67 immunostaining was analysed. PCNA immunostaining resulted in high levels of labelling and the different levels of labelling seen with BrdUrd and Ki-67 were largely lost.

Polyamines as biochemical indicators of radiation injury.

The search for parameters of different nature to quantify radiation damage is carrying on from many years in humans and lab animals. The polyamines (spermidine and spermine) are ubiquitous polycations with many metabolic functions and can be easily assayed by HPLC method. Their involvement in cell proliferation has been evidenced in healthy and tumour tissues. Statistically significant reductions have been demonstrated in tissues and in red blood cells (RBC), in animals and in patients treated by total body irradiation (TBI) before bone marrow transplantation (BMT). In rats submitted to TBI with 3 Gy of gamma radiations, tissue polyamines significantly decrease during the early phase of injury in tissues with high proliferative activity (small intestine, spleen) whereas do not show any modification in kidney. When recovery takes place, the polyamines significantly increase and return to control levels when a normal morphology is restored. In patients submitted to radiation therapy, polyamines have been determined in urine and in RBC of patients with carcinoma of uterine cervix, head and neck and prostate, treated by external radiotherapy, and with thyroid cancer treated with iodine-131 therapy. The most interesting results has been obtained with RBC: in patients treated on the pelvis for prostate cancer a significant reduction during radiotherapy occurs, followed by the maintenance of low levels in patients with favourable outcome. It should be noted that polyamine levels before treatment appeared significantly higher than in healthy controls. After TBI the RBC polyamines show a dramatic fall to extremely low levels during the phase of marrow aplasia. The values show an increase corresponding to the engraftment of transplanted cells and to the following marrow repopulation. These evidences make the RBC polyamines very interesting parameters to monitor the radiation effects on humans.

Proposal for biochemical dosimeter for prolonged space flights.

Radiation dosimetry has been developed by means of physical, chemical and biological methods. A different approach to calculate the absorbed dose is related to the assay in body fluids of some molecules that modify their concentration after irradiation. The salivary glands in humans appear particularly radiosensitive and the effects of ionizing radiation can be evaluated by means of the determination of serum amylase (produced by acinar cells) and Tissue Polypeptide Antigen (TPA, synthesized by ductal cells). Patients submitted to external radiotherapy for tumours localized in the head and neck region show early and late effects on salivary glands. The modification of amylase activity and TPA appear as a progressive statistically significant increase within two days. Levels of 200-300% of baseline value are reached, followed by a rapid return to preirradiation levels. The use of different doses per fraction and fractionation schedules (conventional or multiple daily fractionations) confirm the direct correlation between the absorbed dose and serum amylase and TPA levels. It is worth noting that the irradiation of pancreas region did not produce any effect on amylase activity. The correlation may be assumed as linear for a short dose range (2-6 Gy) whereas in the range from 0.5 to 10 Gy a sigmoid curve represents the experimental data. Both molecules confirm their capability to quantify the absorbed dose in patients with thyroid carcinoma submitted to metabolic treatment with iodine-131. The effects of radiation are species-specific and are absent in laboratory mammals. The easiness of the determination of serum amylase and TPA lead us to propose the test as biochemical dosimeter for cosmic rays exposure during prolonged staying in the space.

Carborane derivatives loaded into liposomes as efficient delivery systems for boron neutron capture therapy.

Boron neutron capture therapy (BNCT) is an anticancer therapy based on the incorporation of (10)B in tumors, followed by neutron irradiation. Recently, the synthesis and delivery of new boronated compounds have been recognized as some of the main challenges in BNCT application. Here, we report on the use of liposomes as carriers for BNCT active compounds. Two carborane derivatives, i.e., o-closocarboranyl beta-lactoside (LCOB) and 1-methyl-o-closocarboranyl-2-hexylthioporphyrazine (H(2)PzCOB), were loaded into liposomes bearing different surface charges. The efficacy of these formulations was tested on model cell cultures, that is, DHD/K12/TRb rat colon carcinoma and B16-F10 murine melanoma. These induce liver and lung metastases, respectively, and are used to study the uptake of standard BNCT drugs, including borophenylalanine (BPA). Boron concentration in treated cells was measured by alpha spectrometry at the TRIGA mark II reactor (University of Pavia). Results showed high performance of the proposed formulations. In particular, the use of cationic liposomes increased the cellular concentration of (10)B by at least 30 times more than that achieved by BPA.

Cell proliferation and differentiation in the small intestine after irradiation with multiple fractions.

Qualitative and quantitative morphologic changes in rat small intestine were studied after abdominal exposure to multiple fractions of gamma radiation. One group of animals received 3 X 2 Gy with one fraction every 4 hours. Another group received two courses of this type with a 16 hour interval between the courses (total dose 6 X 2 Gy). A marked decrease in the number of crypt epithelial cells, and in mitotic and labelling indices, was observed up to 24 to 36 hours after the end of both regimens. Repair and recovery occurred within 72 hours after the end of the last exposure, and the epithelium regained normal morphology. At 1 and 4 hours after the end of the treatment the frequency of S-phase cells along the crypt was greatly reduced and at the following intervals labelled cells occupied the region where differentiation occurs in control animals. During recovery labelled cell distribution showed a gradual return to normal. No substantial differences between the effects of total doses of 6 and 12 Gy were shown except for a greater reduction in crypt epithelial cells at the early time intervals after the larger dose.