Magnetic fluid hyperthermia (MFH)reduces prostate cancer growth in the orthotopic Dunning R3327 rat model

BACKGROUND: Magnetic fluid hyperthermia (MFH) is a new technique for interstitial hyperthermia or thermoablation based on AC magnetic field-induced excitation of biocompatible superparamagnetic nanoparticles. Preliminary studies in the Dunning tumor model of prostate cancer have demonstrated the feasibility of MFH in vivo. To confirm these results and evaluate the potential of MFH as a minimally invasive treatment of prostate cancer we carried out a systematic analysis of the effects of MFH in the orthotopic Dunning R3327 tumor model of the rat. METHODS: Orthotopic tumors were induced by implantation of MatLyLu-cells into the prostates of 48 male Copenhagen rats. Animals were randomly allocated to 4 groups of 12 rats each, including controls. Treatment animals received two MFH treatments following a single intratumoral injection of a magnetic fluid. Treatments were carried out on days 10 and 12 after tumor induction using an AC magnetic field applicator system operating at a frequency of 100 kHz and a variable field strength (0--18 kA/m). On day 20, animals were sacrificed and tumor weights in the treatment and control groups were compared. In addition, tumor growth curves were generated and histological examinations and iron measurements in selected organs were carried out. RESULTS: Maximum intratumoral temperatures of over 70 degrees C could be obtained with MFH at an AC magnetic field strength of 18 kA/m. At a constant field strength of 12.6 kA/m, mean maximal and minimal intratumoral temperatures recorded were 54.8 degrees C (centrally) and 41.2 degrees C (peripherally). MFH led to an inhibition of tumor growth of 44%-51% over controls. Mean iron content in the prostates of treated and untreated (injection of magnetic fluids but no AC magnetic field exposure) animals was 82.5%, whereas only 5.3% of the injected dose was found in the liver, 1.0% in the lung, and 0.5% in the spleen. CONCLUSIONS: MFH led to a significant growth inhibition in this orthotopic model of the aggressive MatLyLu tumor variant. Intratumoral deposition of magnetic fluids was found to be stable, allowing for serial MFH treatments without repeated injection. The optimal treatment schedules and temperatures for MFH need to be defined in further studies.     

Local hyperthermia in prostate cancer

We conducted a clinical trial evaluating the effects of hyperthermia in patients with carcinoma of the prostate, treating 20 patients with newly diagnosed carcinoma of the prostate with local microwave hyperthermia (915 MHz). Histological examination revealed hypoeremic effects and diffuse oedema with interstitial lymphoplasmatic cellular infiltration. However, necrotic tumour cells were not found in any of specimens. A second series consisted of 10 patients with metastasizing carcinoma of the prostate (n = 4 untreated; n = 6 hormone-resistant). For 8 weeks, epirubicin was administered once weekly, followed each time by local microwave hyperthermia 1 h later. The efficacy was evaluated according to the EORTC criteria. In 4 patients with untreated carcinoma no change was found in the size of the prostate or metastases. In 3 of the 6 patients with hormone-resistant carcinoma progressive disease was found, while the other 3 had stable disease. Only in 2 of the 10 patients did the grading of tumour regression reveal any improvement. Cytophotometric studies showed no change of DNA ploidy. Currently we consider hyperthermia unsuitable as monotherapy for carcinoma of the prostate, and the combination of epirubicin and hyperthermia is no more favourable than monotherapy with epirubicin alone. Further studies are necessary to evaluate other cytotoxic regimens and various patterns of application for hyperthermia.     

Laser-induced hyperthermia in rat prostate cancer: role of site of tumor implantation

OBJECTIVES: To investigate the importance of the site of tumor implantation on the treatment response to laser-induced hyperthermia (LIH) of rat prostate cancer (PCa), because interventional manipulations of PCa have been reported to increase metastatic dissemination. METHODS: Seven to nine days after either subcutaneous or orthotopic implantation of MatLyLu cells, LIH (46.5 degrees C) was induced using pulsed irradiations of a neodymium:yttrium-aluminum-garnet laser. Both local control and distant metastases were evaluated. Plasma metalloproteinase 9 (MMP-9) was tested as a possible marker of PCa progression and LIH response. RESULTS: Twelve days after LIH treatment of subcutaneous tumors, the volumes were reduced by 64% after 8 minutes of irradiation, 73% after 10 minutes, 81% after 15 minutes, and 91.1% after 20 minutes. In the orthotopic model, the corresponding tumor reductions were 44% after 10 minutes, 61% after 20 minutes, and 65% after 30 minutes. Lung metastases were observed in only 1 animal with subcutaneous tumors. In contrast, 86% of the orthotopic tumor-bearing animals treated for 30 minutes had lung metastases compared with 23% of the untreated tumor-bearing rats. MMP-9 expression was detected in both orthotopic and subcutaneous tumor tissue and in the plasma of tumor-bearing rats. The prostate tissue of healthy rats and subcutaneous tumor-bearing rats was devoid of MMP-9. The plasma levels of MMP-9 showed a trend toward direct correlation with local tumor control but no correlation with the incidence of metastasis. CONCLUSIONS: These data emphasize the importance of the site of tumor implantation for evaluation of the efficacy of therapeutic interventions and may warrant further studies before widespread clinical application of LIH as monotherapy.     

Thermotherapy using magnetic nanoparticles combined with external radiation in an orthotopic rat model of prostate cancer

BACKGROUND: We evaluated the effects of thermotherapy using magnetic nanoparticles, also referred to as magnetic fluid hyperthermia (MFH), combined with external radiation, in the Dunning model of prostate cancer. METHODS: Orthotopic tumors were induced in 96 male Copenhagen rats. Animals were randomly allocated to eight groups, including controls and groups for dose-finding studies of external radiation. Treatment groups received two serial thermotherapy treatments following a single intratumoral injection of magnetic fluid or thermotherapy followed by external radiation (10 Gy). On day 20, after tumor induction, tumor weights in the treatment and control groups were compared and iron measurements in selected organs were carried out. RESULTS: Mean maximal and minimal intratumoral temperatures obtained were 58.7 degrees C (centrally) and 42.7 degrees C (peripherally) during the first thermotherapy and 55.4 degrees C and 42.3 degrees C, respectively, during the second of two treatment sessions. Combined thermotherapy and radiation with 20 Gy was significantly more effective than radiation with 20 Gy alone and reduced tumor growth by 87.5-89.2% versus controls. Mean iron content in the prostates on day 20 was 87.5% of the injected dose of ferrites, whereas only 2.5% was found in the liver. CONCLUSIONS: An additive effect was demonstrated for the combined treatment at a radiation dose of 20 Gy, which was equally effective in inhibiting tumor growth as radiation alone with 60 Gy. Serial heat treatments were possible without repeated injection of magnetic fluid. The optimal treatment schedules of this combination regarding temperatures, radiation dose, and fractionation need to be defined in further experimental studies.     

Local hyperthermia for prostate cancer.

Hyperthermia for treatment of cancer is known to be beneficial both in itself and in conjunction with other forms of treatment, particularly radiotherapy. We have developed a new machine for local hyperthermia (41-44 degrees C) to the prostate, by transmission of microwaves (915 MHz) via a rectal probe. Patients were treated on an outpatient basis and did not require any anesthesia or sedation. There were no complications. Good results, measured by local control, disappearance of malignancy, relief of obstructive symptoms and pain, have been obtained in a series of 44 cases. More studies with this promising new modality are in progress.     

Evaluation of thermal therapy in a prostate cancer model using a wet electrode radiofrequency probe

PURPOSE: To determine the temperature-time threshold of local cell death in vivo for thermal therapy in a prostate cancer animal model and to use this value as a benchmark to quantify global tissue injury. MATERIALS AND METHODS: Two studies were designed in the Dunning AT-1 rat prostate tumor hind limb model. For both studies, a wet electrode radiofrequency (RF) probe was used to deliver 40 W of energy for 18 to 62 seconds after a 30-second infusion of hypertonic saline/Hypaque through the RF antenna. Thermal history measurements were obtained in tumors from at least two Fluoroptic probes placed radially 5 mm from the axis of a RF probe and 10 mm below the surface of the tissue. In study 1, the thermal history required for irreversible cell injury was experimentally determined by comparing the predicted injury accumulation (omega) with cell viability at the fluoroptic probe locations using an in vivo-in vitro assay. The omega value was calculated from the measured thermal histories using an Arrhenius damage model. In study 2, RF energy was applied for 40 seconds in all cases. At 1, 3, and 7 days after thermal therapy, triphenyltetrazolium chloride dye (TTC) and histologic analyses were performed to assess global tissue injury within a 5-mm radius from the axis of the RF probe. RESULTS: Study 1 showed that cell survival dropped to 0 for 0.42 < omega < 0.7. This result was the basis for selection of 40 seconds of RF thermal therapy in study 2, which yielded omegaave = 0.5 in the tissue 5 mm from the probe axis. Both TTC and histology analysis showed that sham-treated tissue was not irreversibly injured. However, there was an inherent heterogeneity present in the tumor that accounted for as much as 15% necrosis in control or sham-treated tissue. In contrast, at 1, 3, and 7 days after therapy, significantly less enzyme activity was observed by TCC in thermally treated tissue compared with sham-treated tissue (35 v 85%; P < 0.001). Histologic analysis of thermally treated tissues revealed a gradual increase in the percent of coagulative necrosis (47%-70%) with a concomitant decrease in the percentage of shocked cells (53%-28%). At day 7, <3% viability was observed in treated tumors compared with 90% viability in sham-treated tissue. CONCLUSION: The threshold of cellular injury in vivo corresponded to omega > 0.7 (> or =48 degrees C for 40 seconds). Global tissue injury could be conservatively predicted on the basis of local thermal histories during therapy.     

纳米磁微粒体介导热疗治疗肝癌

纳米磁微粒体在交变磁场中可产生热量,利用该特性可研制一种治疗肝癌的绿色疗法。文章综述了纳米磁微粒体材料的特点、交变磁场的研制、纳米磁微粒体介导热疗治疗肝癌的动物实验及临床研究的进展以及尚需要解决的问题。     

Allogeneic whole-tumour cell vaccination in the rat model of prostate cancer

OBJECTIVE: To investigate cancer immunotherapy using whole allogeneic (differing tissue-type) tumour cells as vaccines in the rat prostate cancer model. Materials and methods Two rat models of prostate cancer were used; MAT-LyLu tumours which grow in Copenhagen rats and PAIII tumours which grow in Lobund-Wistar rats, with crossover of the cell lines to test allogeneic vaccination. The cell lines were immunologically characterized by flow cytometry. Irradiated tumour cells were administered as subcutaneous vaccines either before tumour challenge or after tumour establishment (both subcutaneous). A preparation of heat-killed Mycobacterium vaccae bacilli (SRL172) was used as an adjuvant to increase vaccine efficiency. RESULTS: Flow cytometry analysis of the cell lines showed that the PAIII cells had higher levels of major histocompatibility complex (MHC) class I and intercellular adhesion molecule (ICAM-1) expression than the MAT-LyLu cells. However, both tumour cell lines were rejected in their allogeneic hosts. Prophylactic vaccination with allogeneic MAT-LyLu cells protected against PAIII tumour challenge in Lobund-Wistar rats, with 80% of animals surviving for > 5 months, compared with 40% for animals receiving autologous cells. The immunity was prolonged, as rats were protected when rechallenged 5 months later. In Copenhagen rats allogeneic PAIII cells protected against the more aggressive MAT-LyLu tumour challenge only when the cells were combined with SRL172. Initial therapy experiments showed that vaccination with the cell lines mediated only limited tumour regression in the Lobund-Wistar rats. CONCLUSION: The allogeneic tumour cell vaccination model described is valuable for assessing the principle and efficacy of allogeneic prostate cancer cell vaccines for clinical use.     

Evaluation of magnetic resonance imaging-based prostate-specific antigen density of the prostate in the diagnosis of prostate cancer

OBJECTIVES: We evaluated prostate-specific antigen (PSA) density of the prostatic volume (PSAD) estimated using transrectal ultrasonography (TRUS; TRUS-based PSAD), magnetic resonance imaging (MRI; MRI-based PSAD), and PSA density of the transition zone (TZ) volume (PSATZD) estimated using MRI (MRI-based PSATZD) in the diagnosis of prostate cancer (PCa). METHODS: One hundred and twenty patients, who were suspected to have PCa based on PSA, ranged between 4.1 and 20.0 ng/mL were enrolled in this study. RESULTS: The prostatic volume estimated using TRUS was smaller than the volume estimated using MRI by 11.4% in the patients with PSA levels ranging 4.1-20.0 ng/mL, 7.2% in those 4.1-10.0 ng/mL, and 15.7% in those 10.1-20.0 ng/mL, respectively. PSA levels were correlated with the prostatic volume estimated using TRUS and MRI, and TZ volume estimated using MRI in the patients without PCa; however, the level was not correlated with them in the patients with PCa. The area under the receiver operating characteristic curve of MRI-based PSAD was higher than that of TRUS-based PSAD; however, there was no statistical difference. Stepwise logistic regression analysis for the prediction of PCa by using PSA-related parameters confirmed that MRI-based PSATZD was the most significant predictor in patients with PSA levels in the range of 4.1-20.0 ng/mL (P < 0.001), the range of 4.1-10.0 ng/mL (P = 0.002), and the range of 10.1-20.0 ng/mL (P < 0.001), respectively. CONCLUSIONS: The prostatic volume estimated using TRUS was smaller than the volume estimated using MRI. MRI-based PSATZD is the most significant predictor in the four parameters.     

体液中前列腺肿瘤学标记物研究进展

前列腺癌病人的生存率有赖于早期诊断和治疗,生物学标志往往能在其他手段检出癌症之前揭示其存在,因此寻找前列腺癌的生物学标志物一直都是一个重要的研究领域.利用尿液、前列腺液中的肿瘤学标记物对前列腺癌进行早期诊断简便易行.相对其他方法来讲是最为理想的无创性检测手段.本文对近年来在该领域的研究最新进展(如端粒酶、hTERT、DD3、Annexin A3、GSTP1、DPTV等)作一综述.     

A stroma targeted therapy enhances castration effects in a transplantable rat prostate cancer model

BACKGROUND: Castration results in a major involution of the normal prostate gland. This process is initiated by effects in the prostate stroma and vasculature. Castration-induced regression of androgen sensitive prostate tumors is however less prominent and hypothetically this could be related to a limited stromal/vascular response. We therefore used animal tumor models to explore the importance of stroma and vascular effects, and if castration effects could be enhanced by a simultaneous therapy targeting the tumor stroma. METHODS: Using rats with Dunning PAP and H tumors, stereological methods, immunohistochemistry, and Western blotting, we studied the tumor response 7 and 28 days after castration and after the addition of stroma targeted therapies. RESULTS: In the normal ventral prostate (VP) nuclear androgen receptors (AR) were rapidly downregulated after castration. In contrast, the Dunning tumors downregulated the AR in the cancerous epithelium, but not in the surrounding stroma. Vascular regulators such as the angiopoietins, tie 2, and PDGF-Rbeta were not decreased in the stroma after castration, as observed in the VP, creating an environment that prevents vascular involution. When a tumor stroma targeted therapy inhibiting the tie 2 receptor and the PDGF-Rbeta simultaneously was added to castration it resulted in a decreased vascular density, increased tumor cell apoptosis and decreased tumor growth compared to castration alone. CONCLUSIONS: The stroma in highly differentiated androgen sensitive Dunning tumors is apparently androgen insensitive. If this unresponsive stroma is targeted the effects of castration can be enhanced.     

Fe2O3纳米磁流体热疗治疗肝癌

目的　研究在一定高频交变磁场不同浓度的Fe2 O3 纳米磁流体热疗对SMMC772 1肝癌的治疗作用。方法　光学显微镜、电子显微镜观察细胞形态 ,四甲基偶氮唑蓝 (MTT )比色法检测Fe2 O3 纳米磁流体热疗 (MFH)对SMMC772 1肝癌细胞株生长的影响 ,流式细胞仪 (FCM )检测凋亡细胞 ,荷瘤鼠热疗实验检测MFH对肝癌的肿瘤体积抑制率及质量抑制率。结果　SMMC772 1细胞经Fe2 O3 纳米磁流体热疗作用后 ,细胞增殖受到明显抑制 ,细胞凋亡率明显增加 ,且与磁流体浓度呈依赖关系 ;动物实验显示纳米磁流体热疗对肝癌的体积和质量有明显的抑制作用。结论　Fe2 O3 纳米磁流体热疗能抑制肝癌SMMC772 1细胞增殖 ,促进其凋亡 ,并对肝癌显示明显的体积和质量抑制效应 ,对肝癌的治疗有一定的作用。     

交变磁场下Fe3O4纳米磁流体对裸鼠移植性肝癌的杀伤作用

目的 研究交变磁场作用下Fe3O4纳米磁流体对HepG2裸鼠移植性肝癌细胞的杀伤作用.方法 建立HepG2裸鼠肝癌移植模型,将荷瘤裸鼠随机分成空白对照组、磁场空白组、Fe3O4纳米磁流体组3组.其中空白对照组不做任何处理;磁场空白组仅接受磁场作用不做其他处理;Fe3O4纳米磁流体组于裸鼠肿瘤部位直接注射PEG(polyethylene glycol)-PEI(polyetherimide)/Fe3 O4纳米磁流体后接受磁场作用.实验中,交变磁场发生频率为40 kHz,磁场强度峰值为5 kA/m,作用时间为15 min/d,共15 d,观察并记录7、15 d两个时段皮下肿瘤体积、重量的变化情况,以及肿瘤的病理改变和肝癌细胞凋亡情况.结果 裸鼠移植性肝癌肿瘤的成瘤率为100%,7和15 d的记录显示Fe3O4纳米磁流体组裸鼠肿瘤体积和重量均小于其他两组,抑瘤率为54.20%(t=14.506,P＜0.01),明显高于磁场空白组的22.66%(t=7.497,P＜0.05).空白对照组的肿瘤细胞生长良好,细胞密度大,核大深染,形态不规则,核分裂象多见;磁场空白组肿瘤细胞较为稀疏,间质增多,有坏死区形成;纳米磁流体组有大量的肿瘤细胞呈凝固性坏死,细胞核分解、消失,血管明显减少,肿瘤细胞分布稀疏.结论 Fe3O4纳米磁流体在交变磁场的作用下,对HepG2裸鼠移植性肝癌细胞有显著的抑制作用.

Abstract：

Objective To study the therapeutic effect of Fe3O4 nanometer magnetic fluid-induced hyperthermia on implanted liver cancer in nude mice under alternating magnetic field. Methods Nude mice model bearing implanted HepG2 was established. Mice were then randomly divided into 3 groups: the blank control group; the magnetic field group; nanometer magnetic fluid group. The magnetic field group were just put under the magnetic field; Nanometer magnetic fluid group received injection of PEG-PEI/Fe3O4 nanometer magnetic fluid under the alternating magnetic field. At the frequency of 40 kHz, and magnetic field of 5 kA/m, 15 minutes one day in the next 14 days. On the 7th day and the 15th day, the changes of tumor volume and weight were recorded, cell apoptosis were observed and recorded and pathological examination was done. Results On the 7th and the 15th day, in the nanometer magnetic fluid group, tumors' volume was smaller and the weight was lighter than other groups, and the tumor inhibitory rate of 54. 20% (t = 14. 506,P ＜0. 01 ) was significantly higher than the control group and the magnetic field group 22. 66% ( t = 7.497, P ＜ 0. 05 ). In the control group, tumor cells grew well, high density, the nucleus engrained, the shape irregular, the nuclear fission clear; compared with the control group, in the magnetic field group, tumor cells scatter thinly, intercellular substance increases, and necrosis area formed;in the nanometer magnetic fluid group, many of tumor cells died, their cell nucleus broke up and vanished,the blood vessel reduced obviously, and the tumor cell spread thinly. Conclusions Under the alternating magnetic field, PEG-PEI/Fe3O4 nanometer magnetic fluid inhibits liver cancer growth in nude mice model of HepG2.     

Citrate concentrations in human seminal fluid and expressed prostatic fluid determined via 1H nuclear magnetic resonance spectroscopy outperform prostate specific antigen in prostate cancer detection

PURPOSE: We compared the performance of citrate concentration measurements in unprocessed human semen and expressed prostatic secretions from controls and from patients with biopsy confirmed prostate cancer to that of prostate specific antigen testing with respect to specificity and sensitivity for prostate cancer detection. MATERIALS AND METHODS: Semen and expressed prostatic secretions were collected in biopsy proven, prostate cancer bearing and noncancer bearing cases. Citrate concentrations were determined by quantitative in vitro, high field, water suppressed proton nuclear magnetic resonance spectroscopy. Assessments of the diagnostic performance of citrate and prostate specific antigen results in our study populations were made by ROC curve analysis. RESULTS: Citrate was measured in samples from 61 participants, of whom 16 without and 21 with cancer donated semen, and 17 without and 7 with cancer donated expressed prostatic secretions. Mean citrate +/- SE compared to that in controls was 2.7-fold lower in patients with cancer samples in semen (132.2 +/- 30.1 vs 48.0 +/- 7.9 mM, p < 0.05) and expressed prostatic secretions (221.4 +/- 55.4 vs 81.5 +/- 36.0 mM, p < 0.05). ROC curve analysis showed that measurements of citrate in semen performed as well as measurements of citrate in expressed prostatic secretion for detecting prostate cancer (AUC 0.81, 95% CI 0.60 to 0.92 and AUC 0.73, 95% CI 0.38 to 0.90, respectively, p > 0.05). ROC curve analysis also showed that the measurement of citrate in either fluid outperformed prostate specific antigen measurement for detecting prostate cancer in these subjects (AUC 0.61, 95% CI 0.44 to 0.74). CONCLUSIONS: In vitro nuclear magnetic resonance spectroscopic measurement of the citrate concentration in semen or expressed prostatic secretions outperforms prostate specific antigen testing for detecting prostate cancer.     

Persistence of prostatic intraepithelial neoplasia after effective chemoprevention of microscopic prostate cancer with antiandrogen in a rat model

PURPOSE: We determined the chemopreventive effect of the antiandrogen bicalutamide (Zeneca Co., Ltd., Osaka, Japan) on Fisher 344 rat prostate carcinogenesis induced by DMAB (3,2'-dimethyl-4-aminobiphenyl) (Nard Co., Ltd., Osaka, Japan). We have previously reported that rat prostate microscopic carcinogenesis in this model was paradoxically enhanced when continuous treatment with bicalutamide was begun 20 weeks after the initiation of DMAB. In the current study we determined whether antiandrogen would promote or suppress the prostate carcinogenesis when administration was begun at a later period of carcinogenesis. MATERIALS AND METHODS: DMAB at a dose of 50 mg/kg was injected subcutaneously into all animals 10 times at 2-week intervals. To clarify the target lesions of bicalutamide we used 2 control groups (groups 1 and 2). Animals in groups 1 and 2 were autopsied at 60 and 74 weeks, respectively, after the initiation of DMAB. Treatment with bicalutamide began in the 60th week in group 3 rats and continued for 14 weeks. They were sacrificed in the 74th week. RESULTS: Microscopic cancer was revealed in 27% of group 1 rats and the incidence was increased to 42% in group 2 (statistically not significant). Delayed bicalutamide treatment significantly suppressed the cancer lesion. No cancerous lesion was detected in the ventral or other lobes of the prostate of the rats in group 3. In contrast, bicalutamide did not affect the incidence of PIN. The difference in the incidence of PIN in groups 2 and 3 (84% and 78%, respectively) was not significant. CONCLUSIONS: The current investigation indicates that, if bicalutamide is started in the later period, it can efficiently eradicate existing microscopic cancer. Despite this suppressive effect on microscopic cancer bicalutamide permits the persistence of PIN. The latter finding suggests that the sensitivity of PIN to antiandrogen might be more complicated than previously recognized.