Synthesis and F-radiolabeling of thymidine AMBF conjugates.

In pursuit of F-labeled nucleosides for positron emission tomography (PET) imaging, we report on the chemical and radiochemical synthesis of two thymidine (dT) analogs, dT-C-AMBF and dT-N-AMBF, that are radiofluorinated by isotope exchange (IEX) and studied as PET imaging agents in mice with tumor xenografts. dT-C-AMBF shows preferential, and tumor-specific, uptake over dT-N-AMBF. This work provides a new synthetic method in order to access new nucleoside tracers for PET imaging.

Development and validation of a melanoma risk score based on pooled data from 16 case-control studies.

Background: We report the development of a cutaneous melanoma risk algorithm based upon seven factors; hair color, skin type, family history, freckling, nevus count, number of large nevi, and history of sunburn, intended to form the basis of a self-assessment Web tool for the general public.

Methods: Predicted odds of melanoma were estimated by analyzing a pooled dataset from 16 case-control studies using logistic random coefficients models. Risk categories were defined based on the distribution of the predicted odds in the controls from these studies.

Heat shock protein 70 is acute phase reactant: response elicited by tumor treatment with photodynamic therapy.

Oxidative stress in photodynamic therapy (PDT)-treated tumor cells is known to instigate a strong upregulation of the expression of heat shock proteins. However, the treatment of mouse Lewis lung carcinoma (LLC) cells with Photofrin™ PDT resulted in the upregulation of heat shock protein 70 (Hsp70) gene not only in these cells but also in co-incubated untreated Hepa 1-6 cells. To investigate whether this phenomenon extends in vivo, LLC tumors growing in C57BL/6 mice were treated with Photofrin™ PDT.

Complement upregulation in photodynamic therapy-treated tumors: Role of Toll-like receptor pathway and NFkappaB.

Recent investigations have established that complement activation is induced following treatment of solid tumors by photodynamic therapy (PDT). The present study using mouse SCCVII tumor model affirms the proficiency of tumor-associated macrophages (TAMs) to produce complement proteins upon receiving signals such as Hsp70 released from PDT-treated cancer cells. Such communication is shown to trigger signaling involving Toll-like receptors (TLR) 2 and 4 and the activation of transcription factor NFkappaB leading to complement protein production.

Combined treatment of Bcl-2 antisense oligodeoxynucleotides (G3139), p-glycoprotein inhibitor (PSC833), and sterically stabilized liposomal doxorubicin suppresses growth of drug-resistant growth of drug-resistant breast cancer in severely combined immunodeficient mice.

We studied the possibility of increasing sensitization of drug-resistant MDA435/LCC6 multidrug-resistant (MDR) human breast cancer cells to doxorubicin (DOX) by increasing cellular drug retention with P-glycoprotein (P-gp) inhibitor PSC833 in combination with induction of cell death through down-regulation of Bcl-2 protein using Bcl-2 antisense (G3139). In in vitro cytotoxicity assays, the combination of G3139 with DOX exhibited 40% increased cytotoxicity in both wild-type (WT) and MDR cells. PSC833 increased the cytotoxicity of DOX and Taxol with complete and partial reversal of the resistance of MDR cells to DOX and Taxol, respectively.

Ly49 genes in non-rodent mammals.

The Ly49 family of natural killer (NK) receptors is encoded by a highly polymorphic multigene family in the mouse and is also present in multiple copies in the rat. However, this gene exists as a single copy in primates and is mutated to non-function in humans. We recently showed that the cow also likely has only one Ly49 gene, but it is unclear what the Ly49 gene content is for other mammals.

Pharmacokinetics of Bcl-2 antisense oligonucleotide (G3139) combined with doxorubicin in SCID mice bearing human breast cancer solid tumor xenografts.

Purpose: To evaluate the pharmacokinetic (PK) properties of Bcl-2 antisense oligodeoxynucleotide G3139 when combined with the anthracycline anticancer drug doxorubicin (DOX) in a model of MDA435/LCC6 human breast cancer in severely compromised immunodeficient (SCID) mice.

Methods: An orthotopic model of MDA435/LCC6 solid breast tumors was developed by bilateral implantation of passaged cells in female SCID-RAG2 mice. The G3139 plasma profile was compared for two common routes of administration (i.

Radiobiology with heavy charged particles: a historical review.

Radiobiological studies using heavy charged particles followed closely the development of accelerators to produce beams of ever-increasing energy, driven primarily by the aspirations of physicists and chemists interested in the structure of matter. An impressive share of this development took place at Berkeley, beginning with the invention of the cyclotron by Ernest Lawrence in 1930. There followed a series of cyclotrons, synchrotrons and linear accelerators, culminating in the BEVALAC, which provided the first source of very heavy ions (helium to argon) to be used clinically, beginning in 1975.

Comparison between the comet assay and pimonidazole binding for measuring tumour hypoxia.

Pimonidazole is finding increasing use in histochemical analyses of hypoxia in tumours. Whether it can identify every hypoxic cell in a tumour, and whether the usual subjective criteria used to define 'positive' cells are optimal, are less certain. Therefore, our aim was to develop an objective flow cytometry procedure for quantifying pimonidazole binding in tumours, and to validate this method by using a more direct indicator of radiobiologic hypoxia, the comet assay.

Immunotherapy of malignant melanoma in a SCID mouse model using the highly cytotoxic natural killer cell line NK-92.

In this work, we evaluated the potential of the natural killer (NK) cell line NK-92 and its IL-2-independent variants NK-92MI and CI, as immunotherapy for melanoma. In vitro, we found that NK-92 was much more cytotoxic to a number of human melanoma cell lines than lymphokine-activated killer (LAK) cells, particularly at low effector/target (E:T) ratios. In vivo treatment of mice challenged with MEWO melanoma cells with i.

Measurement of delivery and metabolism of tirapazamine to tumour tissue using the multilayered cell culture model.

Purpose: Efficient extravascular penetration is essential for the optimal activity of most anticancer drugs and is particularly relevant to bioreductive cytotoxins which target hypoxic cells that can be located distal to functional blood vessels within tumours. Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-di-N-oxide; Triazone; SR 259075; formerly SR 4233) is a lead bioreductive cytotoxin currently undergoing clinical evaluation. It exhibits preferential cytotoxicity towards cells at reduced oxygen tension, and could complement existing anticancer therapies where hypoxic cells are believed to constitute a refractory population.

A human endogenous retrovirus suppresses translation of an associated fusion transcript, PLA2L.

Human endogenous retroviruses (HERVs) are repetitive, noninfectious chromosomal elements degenerated from exogenous retroviruses. The HERV-H family is composed of approximately 1,000 elements which are dispersed throughout the human genome. We have shown previously that an HERV-H element splices into a downstream locus, termed PLA2L, which has a large open reading frame (ORF) containing two domains with phospholipase A2 homology.

Assessment of toxicity of bis-platinum complexes in hypoxic and aerobic cells.

There is considerable interest in the bis-platinum series of complexes as potential chemotherapeutic agents, due to their activity in cisplatin-resistant lines and in various tumor types. Our interest in their hypoxic selectivity stems from the fact that cisplatin exhibits greater cytotoxicity in hypoxic than aerobic cells. Unlike nitroaromatics, quinones, tirapazamine and many other hypoxia selective agents, a 'bioreductive' moiety cannot explain these observations.

Tumor repopulation during radiotheraphy: quantitation in two xenografted human tumors.

Purpose: "Accelerated repopulation" has generated considerable recent interest. Our purpose in this study was to determine whether flow cytometry measurements like those used for classical Tpot determinations could be used to quantify the rate of repopulation, and the time of its initiation in irradiated human tumor xenografts.

Methods And Materials: Two human tumor cell lines (SiHa, a squamous cell cervix carcinoma, and WiDr, an adenocarcinoma of the colon) were grown as subcutaneous xenografts in SCID mice.

Substructure in the cell survival response at low radiation dose: effect of different subpopulations.

In order to obtain more accurate measurements of cell survival after low doses of radiation, we have used the cell sorter assay, in which a cell sorter is used to accurately count out the number of cells plated for colony formation. This method, combined with data averaging, permits measurements of survival with superior precision, which have revealed that there is substructure in the radiation response of asynchronously dividing Chinese hamster cells. The substructure, observed at doses of a few Gy, has features of a 2-component response, consistent with the presence of subpopulations of cells of different cell-cycle-related radiosensitivity.

Arsenic and chromium enhance transformation of bovine papillomavirus DNA-transfected C3H/10T1/2 cells.

Tumor promoters such as phorbol esters, teleocidin and okadaic acid increase the numbers of multilayered, transformed foci produced by BPV DNA-transfected C3H/10T1/2 cells. We questioned whether arsenic and chromium, which are known human carcinogens also enhance transformation of BPV DNA-transfected C3H/10T1/2 cells. Cr(III) potassium sulfate at 100 microM enhanced transformation by 1.

Proliferation of individual hematopoietic progenitors purified from umbilical cord blood.

In previous studies, we described long-term cultures of subpopulations of CD34+ cord blood cells that were fractionated using antibodies specific for CD45RA and CD71. In the present study, we plated the most primitive CD34+CD45RAlowCD71low cells individually and analyzed the proliferation and expansion kinetics of the various hematopoietic progenitors included in this subpopulation. The proliferation capacity of single progenitors was assessed by the total number of cells produced, and their expansion capacity was assessed by the production of CD34+ and colony-forming cells.

Cytotoxic effect of RB 6145 in human tumour cell lines: dependence on hypoxia, extra- and intracellular pH and drug uptake.

Low pH and hypoxia are a common feature of many solid tumours. This study examined the effect of these two conditions on the cytotoxic properties of the bifunctional agent RB 6145, the prodrug of RSU 1069. The effect of acidic pH on RB 6145 toxicity was examined in six human tumour cell lines under hypoxic conditions and was found to have little effect in HT 29, A549, U373 and HT 144 cells.

Histometric texture analysis of DNA in thin sections from breast biopsies. Application to the detection of malignancy-associated changes in carcinoma in situ.

Objective: To evaluate histometric measurement of nuclear texture in breast biopsy sections in order to detect malignancy-associated changes in apparently normal tissue in the vicinity of carcinoma in situ.

Study Design: We previously showed that image cytometry measurements of nuclear features--foremost, texture features, describing the organization of Feulgenstained DNA in the cell--can be used to distinguish normal-appearing, diploid epithelial cells from patients with invasive carcinoma of the breast from those with benign biopsies. In that study, referred to as the "single cell analysis," images of at least 200 epithelial cells were acquired for each slide, and substantial user interaction was required to segment cells from each field.

The cytotoxicity of melphalan and its relationship to pH, hypoxia and drug uptake.

In the present in vitro studies we examined the effect of hypoxia and acidic pH, two important consequences of reduced blood flow in vivo, on the cytotoxicity of melphalan treatment in Chinese hamster V79-WNRE and SiHa human tumor cells. Cells were exposed to various concentrations of melphalan for 1 hr at 37 degrees C under oxic or hypoxic conditions; pH 6.6 or 7.

The influence of microenvironmental factors during cancer therapy.

The response of tumour cells to chemotherapy or radiotherapy is clearly dependent upon the inherent sensitivity of the cells to those agents. That sensitivity can, however, be markedly affected by the biochemical and physiological status of the tumour cell during treatment. In this review, a critique of the current evidence for, and the extent of, microenvironmental heterogeneity in tumours is presented.

Potentiation of photodynamic therapy by immunotherapy: the effect of schizophyllan (SPG).

Treatment of squamous cell carcinoma (SCCVII) bearing mice with the immunostimulant schizophyllan (SPG) raised the relative content of Mac-1 positive host cells infiltrating the tumor and increased photofrin retention in these tumors. In vitro colony formation assay following photofrin-based photodynamic therapy (PDT) in vivo revealed a greater killing of tumor cells in the SPG pre-treated group, particularly pronounced when the tumor excision was delayed for 8 h after PDT. The tumor cure rate increased approximately three times when PDT was preceded by the SPG therapy.

Quantitative precision of an automated image cytometric system for the measurement of DNA content and distribution in cells labeled with fluorescent nucleic acid stains.

An automated image cytometric system is described for the measurement of DNA content and distribution in cells stained with fluorescent DNA binding or intercalating compounds. The quantitative precision of integrated optical intensity (IOI) measurements using this system was estimated to be 2.0%, based on the coefficient of variation (cv) of the IOI of DNA check beads.