boron and Carcinoma--Squamous-Cell

Boron neutron capture therapy (BNCT) is a binary cancer therapy that involves boron administration and neutron irradiation. The nuclear reaction caused by the interaction of boron atom and neutron produces heavy particles with highly cytocidal effects and destruct tumor cells, which uptake the boron drug. p-Boronophenylalanine (BPA), an amino acid derivative, is used in BNCT. Tumor cells with increased nutrient requirements take up more BPA than normal tissues via the enhanced expression of LAT1, an amino acid transporter. The current study aimed to assess the correlation between the expression of LAT1 and the uptake capacity of BPA using genetically modified LAT1-deficient/enhanced cell lines. We conducted an in vitro study, SCC7 tumor cells wherein LAT1 expression was altered using CRISPR/Cas9 were used to assess BPA uptake capacity. Data from The Cancer Genome Atlas (TCGA) were used to examine the expression status of LAT1 in human tumor tissues, the potential impact of LAT1 expression on cancer prognosis and the potential cancer indications for BPA-based BNCT. We discovered that the strength of LAT1 expression strongly affected the BPA uptake ability of tumor cells. Among the histologic types, squamous cell carcinomas express high levels of LAT1 regardless of the primary tumor site. The higher LAT1 expression in tumors was associated with a higher expression of cell proliferation markers and poorer patient prognosis. Considering that BPA concentrate more in tumors with high LAT1 expression, the results suggest that BNCT is effective for cancers having poor prognosis with higher proliferative potential and nutritional requirements.

Topics: Boron; Boron Compounds; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Humans; Large Neutral Amino Acid-Transporter 1; Neutrons

Topics: Animals; Boron; Boron Compounds; Boron Neutron Capture Therapy; Brain Neoplasms; Carcinoma, Squamous Cell; Disease Models, Animal; Humans; Mouth Neoplasms; Phenylalanine

Purpose To evaluate the effect of oxygen pressure during incubation with a (10)B-carrier on (10)B uptake capacity of cultured p53 wild-type and mutated tumor cells. Materials and methods Cultured human head and neck squamous cell carcinoma cell line transfected with mutant TP53 (SAS/mp53), or with a neo vector as a control (SAS/neo) was incubated with L-para-boronophenylalanine-(10)B (BPA) or sodium mercaptoundecahydrododecaborate-(10)B (BSH) as a (10)B-carrier at the (10)B concentration of 60 ppm for 24 h under aerobic (20.7% of oxygen) or hypoxic (0.28% of oxygen) conditions. Immediately after incubation, cultured tumor cells received reactor thermal neutron beams, and a cell survival assay was performed. (10)B concentration of cultured SAS/neo or SAS/mp53 cells incubated under aerobic or hypoxic conditions was determined with a thermal neutron guide tube. Results Hypoxic incubation significantly decreased (10)B concentration of cultured cells with a clearer tendency observed following BPA than BSH treatment in both SAS/neo and SAS/mp53 cells. Following neutron beam irradiation, SAS/mp53 cells showed significantly higher relative biological effectiveness values than SAS/neo cells because of the significantly lower radiosensitivity of SAS/mp53 to γ-rays than SAS/neo cells. Conclusion Oxygen pressure during incubation with a (10)B-carrier had a critical impact on (10)B uptake of cultured tumor cells.

Topics: Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Cell Survival; Drug Carriers; Head and Neck Neoplasms; Humans; Isotopes; Mutation; Oxygen; Radiopharmaceuticals; Squamous Cell Carcinoma of Head and Neck; Tumor Suppressor Protein p53

Previous studies have demonstrated that X-ray irradiation affects angiogenesis in tumors. Here, we studied the effects of gamma-ray irradiation on boron-10 compound accumulation in a murine tumor model. The mouse squamous cell carcinoma was irradiated with gamma-ray before BSH ((10)B-enriched borocaptate sodium) administration. Then, the boron-10 concentrations in tumor and normal muscle tissues were measured by prompt gamma-ray spectrometry (PGA). A tumor blood flow assay was performed, and cell killing effects of neutron irradiation with various combinations of BSH and gamma-rays were also examined. BSH concentrations of tumor tissues were 16.1 +/- 0.6 microg/g, 16.7 +/- 0.5 microg/g and 17.8 +/- 0.5 microg/g at 72 hours after gamma-ray irradiation at doses of 5, 10, and 20 Gy, compared with 13.1 +/- 0.5 microg/g in unirradiated tumor tissues. The enhancing inhibition of colony formation by neutron irradiation with BSH was also found after gamma-ray irradiation. In addition, increasing Hoechst 33342 perfusion was also observed. In this study, we demonstrated that gamma-ray irradiation enhances BSH accumulation in tumors. The present results suggest that the enhancement of (10)B concentration that occurs after gamma-ray irradiation may be due to the changes in the extracellular microenvironment, including in tumor vessels, induced by gamma-ray irradiation.

Topics: Animals; Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Dose-Response Relationship, Radiation; Gamma Rays; Isotopes; Metabolic Clearance Rate; Mice; Radiopharmaceuticals

Recently, Boron neutron capture therapy (BNCT) was successfully applied to treat experimental squamous cell carcinomas (SCC) of the hamster cheek pouch mucosa, with no damage to normal tissue. It was also shown that treating spontaneous nasal planum SCC in terminal feline patients with low dose BNCT is safe and feasible. In an extension of this work, the present study aimed at evaluation of the response of tumor and dose-limiting normal tissues to potentially therapeutic BNCT doses. Biodistribution studies with (10)B-boronophenylalanine (BPA enriched in (10)B) as a (10)B carrier were performed on three felines that showed advanced nasal planum SCC without any standard therapeutic option. Following the biodistribution studies, BNCT mediated by (10)BPA was done using the thermalized epithermal neutron beam at the RA-6 Nuclear Reactor. Follow-up included clinical evaluation, assessment of macroscopic tumor and normal tissue response and biopsies for histopathological analysis. The treated animals did not show any apparent radiation-induced toxicity. All three animals exhibited partial tumor control and an improvement in clinical condition. Enhanced therapeutic efficacy was associated with a high (10)B content of the tumor and a small tumor size. BNCT is therefore believed to be potentially effective in the treatment of spontaneous SCC. However, improvement in targeting (10)B into all tumor cells and delivering a sufficient dose at a greater depth are still required for the treatment of deep-seated, large tumors. Future studies are needed to evaluate the potential efficacy of the dual mode cellular (e.g. BPA-BNCT) and vascular (e.g. GB-10-BNCT) targeting protocol in a preclinical scenario, employing combinations of (10)B compounds with different properties and complementary uptake mechanisms.

Topics: Animals; Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Cat Diseases; Cats; Dose-Response Relationship, Radiation; Female; Isotopes; Male; Neoplasm Staging; Neutrons; Nose; Nose Neoplasms; Phenylalanine; Treatment Outcome

To evaluate the usefulness of 5 new 10B-compounds (TX-2091, TX-2095, TX-2097, TX-2100, and TX-2110) as 10B-carriers in boron neutron capture therpy (BNCT). They were conjugates that had been synthesized from a hypoxia-specific cytotoxic bioreductive agent, quinoxaline oxide TX-402, and a clinically used 10B-carrier, sodium borocaptate-10B (BSH).. The 5 new compounds were hybrid compounds that have both a hypoxic cytotoxin unit and a thermal neutron-sensitizing unit, BSH. These new compounds and BSH were administered intraperitoneally to SCC VII tumor-bearing mice. Then, the 10B concentrations in the tumors and normal tissues were measured by gamma-ray spectrometry. Subsequently, SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, then treated with TX-2100, which was chosen based on the results of the above-mentioned biodistribution analyses, or BSH in the same manner as in the biodistribution studies. Right after irradiation, during which intratumor 10B concentrations were kept at levels similar to each other, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling [= quiescent (Q) cells] was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in the total (P+Q) tumor cell population was determined from the tumors that were not pretreated with BrdU. Clonogenic cell survival was also determined in mice given no BrdU.. 10B biodistribution analyses in tumors, brain, skin, muscles, blood, and liver indicated that TX-2100 has the most favorable characteristics for concentrating a sufficient amount of 10B in tumors and maintaining a high enough 10B concentration during irradiation. In addition, TX-2100 had a significantly stronger radio-sensitizing effect with reactor thermal neutron beams than BSH on both total and Q cells in solid tumors. Further, TX-2100 clearly exhibited a radio-sensitizing effect with gamma-rays not only on total cells but also on Q and hypoxic tumor cells, which was not achieved by BSH.. A 10B-carrier that acts as a hypoxic cytotoxin on tumor cells as well as having the potential to keep 10B in tumors and sensitize tumor cells more markedly than conventional 10B-carriers, such as TX-2100, is a promising candidate for use in BNCT.

Topics: Animals; Borohydrides; Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Fluorescent Antibody Technique, Indirect; Isotopes; Mice; Molecular Structure; Nitriles; Nitroimidazoles; Quinoxalines; Sulfhydryl Compounds; Tissue Distribution

Boron neutron capture therapy (BNCT) is a unique radiation therapy in which boron compounds are trapped into tumor cells. To determine the biodistribution of boronophenylalanine (BPA) in nude mice carrying oral squamous cell carcinoma (SCC), BPA was administered at a dose of 250 mg/kg body weight intraperitoneally. Two hours later, (10)B concentration in the tumor was 15.96 ppm and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 6.44, 4.19, 4.68 and 4.56, respectively. Two hours after the administration of borocaptate sodium (BSH) at a dose of 75 mg/kg body weight, (10)B concentration in the tumor was 3.61 ppm, and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 0.77, 1.05, 0.60 and 0.59, respectively. When cultured oral SCC cells were incubated with BPA or BSH for 2 h and then exposed to thermal neutrons, the proportion of survival cells that were capable of forming cell colonies decreased exponentially, depending on (10)B concentration. BPA-mediated BNCT was more efficient than BSH-mediated BNCT. Addition of boron compounds in the cell suspension during neutron irradiation enhanced the cell-killing effect of the neutrons. These results indicate that BPA is more selectively incorporated into human oral SCC as compared with normal oral tissues, and that both extra- and intra-cellular BPA contribute to the cell-killing effect of BNCT. BPA may be a useful boron carrier for BNCT in the treatment of advanced oral SCC.

Topics: Animals; Borohydrides; Boron; Boron Compounds; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Survival; Female; Isotopes; Mice; Mice, Nude; Mouth Neoplasms; Phenylalanine; Relative Biological Effectiveness; Sulfhydryl Compounds

Copper tetracarboranyltetraphenylporphyrin (CuTCPH) is a minimally toxic carborane-containing porphyrin that has safely delivered high concentrations of boron for experimental boron neutron capture therapy (BNCT). Copper octabromotetracarboranylphenylporphyrin (CuTCPBr), synthesized by bromination of CuTCPH, is one of several new minimally toxic analogues of CuTCPH being studied in our laboratory, which could possess comparable or better tumour-targeting properties with enhanced tumour cytotoxicity. Its biodistribution, biokinetics and toxicity in mice with subcutaneous EMT-6 (mammary) or SCCVII (squamous cell) carcinomas were compared with those of CuTCPH. The administration of approximately 200 mg kg(-1) of either porphyrin in six intraperitoneal injections over 2 days had no apparent effect, but administration of approximately 400 mg kg(-1) slightly lowered body weights, elevated alanine and aspartate transaminase activities in blood plasma, and depressed blood platelet counts for several days. Enzymes and platelets returned to normal within 5 days after those injections and body weights returned to normal within 2 weeks. High average concentrations of boron from either porphyrin were achieved in the two tumour models from a total dose of approximately 200 mg kg(-1). The high tumour boron concentration decreased slowly while concentrations in blood decreased rapidly. Boron concentrations in brain and skin were consistently lower than in tumour by a factor of 10 or more. Although either CuTCPH or CuTCPBr can be labelled with (64)Cu for imaging by positron emission tomography (PET), CuTCPBr can also be labelled by (76)Br, another PET-imageable nuclide.

Topics: Animals; Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Dose-Response Relationship, Drug; Female; Mammary Neoplasms, Experimental; Metalloporphyrins; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Neoplasm Transplantation; Tissue Distribution

The aim of this study was to evaluate the antitumor efficacy of the vascular targeting agent ZD6126 (N-acetylcochinol-O-phosphate) in the rodent squamous cell carcinoma (SCC) VII carcinoma model, in combination with boron neutron capture therapy (BNCT).. Sodium borocaptate-(10)B (BSH, 125 mg/kg, i.p.) or l-p-boronophenylalanine-(10)B (BPA, 250 mg/kg, i.p.) was injected into SCC VII tumor-bearing mice, and 15 min later, ZD6126 (100 mg/kg, i.p.) was administered. Then, the (10)B concentrations in tumors and normal tissues were measured by prompt gamma-ray spectrometry. On the other hand, for the thermal neutron beam exposure experiment, SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, followed by treatment with a (10)B-carrier and ZD6126 in the same manner as the above-mentioned (10)B pharmacokinetics analyses. To obtain almost similar intratumor (10)B concentrations during neutron exposure, thermal neutron beam irradiation was started from the time point of 30 min after injection of BSH only, 90 min after BSH injection for combination with ZD6126, 120 min after the injection of BPA only, and 180 min after BPA injection for combination with ZD6126. Right after irradiation, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (quiescent [Q] cells) was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The clonogenic cell survival assay was also performed in mice given no BrdU.. Pharmacokinetics analyses showed that combination with ZD6126 greatly increased the (10)B concentrations in tumors after 60 min after BSH injection and after 120 min after BPA injection. The concentrations of (10)B from BSH in normal tissues were also raised by combination with ZD6126, although not so clearly as those in tumors. Combination with ZD6126 had almost no effect on the concentrations of (10)B from BPA in normal tissues. The clonogenic surviving fractions of total tumor cells and the MN frequencies of both total and Q tumor cells were reduced and increased by combination with ZD6126, respectively, whether BSH or BPA was employed. However, the degrees of these changes in the clonogenic surviving fractions and the MN frequencies were more obviously observed in tumors from BSH-injected mice than from BPA-injected mice, and in Q tumor cells than in total tumor cells regardless of the employed (10)B-carrier.. Combination with ZD6126 was regarded as more promising in BSH-BNCT than BPA-BNCT, and more effective for enhancing the sensitivity of the Q tumor cells than that of the total tumor cells. This resulted in the decrease in the extended difference in the sensitivity between the total and Q tumor cells caused by the use of (10)B-carrier for BNCT.

Topics: Animals; Borohydrides; Boron; Boron Neutron Capture Therapy; Bromodeoxyuridine; Carcinoma, Squamous Cell; Isotopes; Mice; Micronucleus Tests; Organophosphorus Compounds; Sulfhydryl Compounds; Tumor Stem Cell Assay

Reoxygenation in quiescent (Q) and total tumor cells within solid tumors after thermal neutron irradiation with or without (10)B-compound was examined, comparing with that following gamma-ray irradiation.. C3H/He mice bearing SCC VII tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty minutes after intraperitoneal injection of sodium borocaptate-(10)B (BSH), or 3 h after oral administration of dl-p-boronophenylalanine-(10)B (BPA), the tumors were irradiated with thermal neutrons, or those without (10)B-compounds were irradiated with thermal neutrons alone or gamma-rays. At various time points after each treatment, a series of test doses of gamma-rays were given to tumor-bearing mice while alive or after being killed to obtain hypoxic fractions in the tumors. Immediately after irradiation, the tumors were excised, minced, and trypsinized. Following incubation of tumor cells with cytokinesis blocker, the micronucleus (MN) frequency in cells without BrdU labeling ( = Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The MN frequency of BrdU-unlabeled cells was then used to calculate the surviving fraction of the unlabeled cells from the regression line for the relationship between the MN frequency and the surviving fraction of total tumor cells.. In both total and Q tumor cells, the hypoxic fractions immediately after each treatment went up suddenly. Reoxygenation after each treatment occurred more rapidly in total cells than in Q cells. In both cell populations, reoxygenation appeared to be rapidly induced in the following order: neutron irradiation without (10) gamma-ray irradiation.. Based on our previous report that total and Q cell fractions within these tumors have larger acutely and chronically hypoxic fractions, respectively, acute hypoxic cells appeared to play a larger role in reoxygenation. BSH was thought to have a potential to distribute more homogeneously in solid tumors than BPA, because BSH induced the nearer reoxygenation pattern to that following neutron irradiation alone than BPA.

Topics: Animals; Antimetabolites, Antineoplastic; Boron; Boron Neutron Capture Therapy; Bromodeoxyuridine; Carcinoma, Squamous Cell; Cell Division; Cell Hypoxia; Cell Survival; Dose-Response Relationship, Radiation; Female; Fluorescent Antibody Technique, Indirect; Isotopes; Linear Energy Transfer; Mice; Mice, Inbred C3H; Micronucleus Tests; Oxygen Consumption; Radiation-Sensitizing Agents; Radiobiology; Regression Analysis

In neutron capture therapy, whose effectiveness depends on the tumor distribution of neutron capture compound and the neutron energy distribution, controlling quiescent tumor cells with clonogenic potential is critical for therapeutic gain, as is the case in conventional radio- and chemotherapy. Tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating cells. After administration of sodium borocaptate-10B (BSH), dl-p-boronophenylalanine-10B (BPA) or gadodiamide hydrate (Omniscan), the tumors were irradiated with neutrons of different cadmium (Cd) ratio, and then isolated and incubated with cytochalasin-B (a cytokinesis blocker). The micronucleus (MN) frequency in cells without BrdU labeling (quiescent cells) was determined using immunofluorescence staining for BrdU, and that for total cells was obtained from tumors not pretreated with BrdU. Without drugs, quiescent cells showed lower MN frequencies than total cells, but neutron irradiation reduced gamma-ray sensitivity difference between the two. Relative biological effectiveness (RBE) of neutrons compared with gamma-rays was greater in quiescent cells than in total cells, and low Cd ratio neutrons tended to exhibit large RBE values. With neutron capture compounds, MN frequency for each cell population was increased, especially when high Cd ratio neutrons were used. BPA increased the MN frequency for total cells to a greater extent than BSH. However, the sensitivity of quiescent cells treated with BPA was lower than that in BSH-treated quiescent cells. This tendency was clearly observed in high Cd ratio neutrons. Omniscan only slightly increased the MN frequency in both cell populations, compared with irradiation alone, without drugs. From the viewpoint of increasing the quiescent cell sensitivity, tumors should be irradiated with high Cd ratio neutrons after BSH administration.

Topics: Animals; Borohydrides; Boron; Boron Compounds; Boron Neutron Capture Therapy; Bromodeoxyuridine; Cadmium Radioisotopes; Carcinoma, Squamous Cell; Contrast Media; Cytochalasin B; Dose-Response Relationship, Radiation; Female; Fluorescent Antibody Technique, Indirect; Gadolinium; Gadolinium DTPA; Injections, Intraperitoneal; Isotopes; Mice; Mice, Inbred C3H; Micronucleus Tests; Neoplasm Transplantation; Phenylalanine; Radiation-Sensitizing Agents; Sulfhydryl Compounds; Tumor Cells, Cultured

Boron neutron capture therapy (BNCT) destroys tumor cells by means of alpha particles and recoil protons emitted by 10B(n, alpha)7Li reaction. For BNCT to be effective, the tumor/normal tissue concentration ratio of 10B must be larger than 1.0, because neutron distribution is not selective. We examined the combination of 10B-enriched borocaptate sodium (BSH) with flavone acetic acid (FAA) as a model compound which causes vascular collapse in squamous cell carcinoma in mice (SCCVII tumors) and would increase the tumor/normal tissue concentration ratio of 10B. FAA (200 mg/kg, i.p.) was injected, and 5 min later BSH (75 mg/kg, i.v.) was administered, followed 15 to 180 min later by irradiation with thermal neutrons. The 10B concentrations were measured by prompt gamma ray spectrometry. Without FAA, tumor 10B concentrations were less than or equal to normal tissue concentrations at all time intervals, except that the concentrations were 1.7- to 2.7-fold greater in tumor than muscle at 15 and 180 min after injection of BSH. With FAA, 10B concentrations 2.1- to 6.9-fold greater in tumor than in muscle were achieved at all intervals tested. For blood and skin, significant differential accumulations were found in tumors at 120 and 180 min. Tumor/liver ratios were less than 1 at all times. Cell survival was determined by in vivo/in vitro colony assay, and increasing radiosensitization correlated with increasing tumor 10B concentrations, whether or not they were achieved with FAA. Tumor control rates, determined at 180 days after BNCT, similarly appeared to depend only on 10B levels at the time of irradiation. Because 10B levels correlate with the radiation response of tissues, a therapeutic gain would be expected whenever the tumor levels exceed normal tissue levels, such as in tumors located in muscle irradiated at 15-180 min after FAA + BSH, or in those in skin irradiated at 120 and 180 min.

Topics: Animals; Antineoplastic Agents; Borohydrides; Boron; Boron Neutron Capture Therapy; Carcinoma, Squamous Cell; Cell Survival; Flavonoids; Male; Mice; Mice, Inbred C3H; Muscles; Neoplasm Transplantation; Sulfhydryl Compounds; Tumor Cells, Cultured

The effectiveness of boron neutron capture therapy is predicted to be dependent not only on the amount of boron taken up by the target cells but also on the intracellular distribution of boron. Using the isotopic imaging technique ion microscopy, we have quantitatively determined uptake and intracellular distribution of Na2B12H11SH, a promising boron drug for boron neutron capture therapy, in four human cell lines: U87 glioblastoma cells, HeLa epithelioid carcinoma cells, GM 2408b mutant skin fibroblasts, and GM 3348b skin fibroblasts. The boron uptake of all four cell lines, after exposure to 100-500 micrograms/ml Na2B12H11SH, increased as the dosages were increased but showed a tendency toward saturation. Boron was more concentrated in the cytoplasm than in the nucleus but was not strongly localized within cells. There were no significant differences in boron uptake among the four cell lines. A retention experiment identified at least two different intracellular boron pools, and cells lost greater than 60% of intracellular boron within 1 h upon changing to Na2B12H11SH-free medium, indicating a largely low affinity binding.

Topics: Boranes; Borohydrides; Boron; Brain Neoplasms; Carcinoma, Squamous Cell; Cell Line, Transformed; Culture Techniques; Fibroblasts; Glioma; HeLa Cells; Humans; Intracellular Fluid; Mass Spectrometry; Microscopy; Neutron Capture Therapy; Subcellular Fractions; Sulfhydryl Compounds; Tumor Cells, Cultured

Topics: Boron; Carcinoma, Squamous Cell; Cell Survival; Culture Media; Fast Neutrons; Head and Neck Neoplasms; Humans; Isotopes; Melanoma; Neutrons; Particle Accelerators; Radiotherapy Dosage; Tumor Cells, Cultured