Macrophage migration inhibitory factor downregulation: a novel mechanism of resistance to anti-angiogenic therapy

Anti-angiogenic therapies for cancer such as VEGF neutralizing antibody bevacizumab have limited durability. While mechanisms of resistance remain undefined, it is likely that acquired resistance to anti-angiogenic therapy will involve alterations of the tumor microenvironment. We confirmed increased tumor-associated macrophages in bevacizumab-resistant glioblastoma patient specimens and two novel glioblastoma xenograft models of bevacizumab resistance. Microarray analysis suggested downregulated macrophage migration inhibitory factor (MIF) to be the most pertinent mediator of increased macrophages. Bevacizumab-resistant patient glioblastomas and both novel xenograft models of resistance had less MIF than bevacizumab-naive tumors, and harbored more M2/protumoral macrophages that specifically localized to the tumor edge. Xenografts expressing MIF-shRNA grew more rapidly with greater angiogenesis and had macrophages localizing to the tumor edge which were more prevalent and proliferative, and displayed M2 polarization, whereas bevacizumab-resistant xenografts transduced to upregulate MIF exhibited the opposite changes. Bone marrow-derived macrophage were polarized to an M2 phenotype in the presence of condition-media derived from bevacizumab-resistant xenograft-derived cells, while recombinant MIF drove M1 polarization. Media from macrophages exposed to bevacizumab-resistant tumor cell conditioned media increased glioma cell proliferation compared with media from macrophages exposed to bevacizumab-responsive tumor cell media, suggesting that macrophage polarization in bevacizumab-resistant xenografts is the source of their aggressive biology and results from a secreted factor. Two mechanisms of bevacizumab-induced MIF reduction were identified: (1) bevacizumab bound MIF and blocked MIF-induced M1 polarization of macrophages; and (2) VEGF increased glioma MIF production in a VEGFR2-dependent manner, suggesting that bevacizumab-induced VEGF depletion would downregulate MIF. Site-directed biopsies revealed enriched MIF and VEGF at the enhancing edge in bevacizumab-naive patients. This MIF enrichment was lost in bevacizumab-resistant glioblastomas, driving a tumor edge M1-to-M2 transition. Thus, bevacizumab resistance is driven by reduced MIF at the tumor edge causing proliferative expansion of M2 macrophages, which in turn promotes tumor growth.

Endoxifen for breast cancer: Multiple-dose, dose-escalation study characterizing pharmacokinetics and safety in metastatic breast cancer patients

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Background: Endoxifen is an active metabolite of tamoxifen, a drug used in the treatment of breast cancer. To be clinically effective, tamoxifen must be converted to endoxifen by CYP2D6. Direct administration of endoxifen would not be subject to pharmacogenetic variations or drug-drug interactions. Our preclinical studies (Breast Cancer Treat 122, 579-584, 2010) have validated the concept of using endoxifen for the treatment of breast cancer. In human (Clin. Pharmacol. Ther. 88, 814-817, 2010), the single oral doses tested up to 4 mg of endoxifen were safe, well tolerated and bioavailable. Methods: A multiple-dose escalating study was conducted in 3 cohorts and each cohort had 6 patients (18 metastatic breast cancer patients). Endoxifen at 3 dose levels (2, 4, or 8 mg) was given once daily for 28 days. Routine laboratory tests, vital signs and electrocardiograms were measured throughout the study. Blood samples for PK analysis were collected after 28 days post dose. Endoxifen in plasma samples was determined using LC-MS/MS. Results: Endoxifen was found to be safe up to 8.0 mg. At steady state, it displays dose-proportional PK with respect to Cmax and AUC ( see Table below). Conclusions: Multiple daily endoxifen doses of 4.0-8.0 mg resulted in endoxifen exposures that would be sufficient for effective therapy. The favorable safety and multiple-dose PK profile of endoxifen warrants further evaluation of safety and efficacy of endoxifen in breast cancer patients. [Table: see text]

Surgical approaches to posterior polar cataract: a review

The aim of this study is to provide a comprehensive overview of surgical methods used in the emulsification of posterior polar cataracts (PPCs) that have been devised to minimize the risk of posterior capsule rupture (PCR) and its consequences. A Pubmed and Medline search of relevant literature on PPC was done. Only articles relevant to the treatment of PPC were included. The posterior capsule in eyes with PPC are known to have an abnormal adhesion to the polar opacity or a pre-existing weakness of the capsule that predisposes the eye to PCR. To circumvent the consequences of cleaving the abnormal adhesion, a majority of the surgeons use the anterior approach through the limbus, whereas some advocate the posterior approach through the pars plana. Emulsifying the nucleus and cleaving the central opacity of the PPC off the posterior capsule without disrupting its integrity provides optimal surgical outcomes. To achieve this, various modifications have been applied by surgeons during different phases of surgery. The advantages, disadvantages, complications, and results of each method have been discussed. Phacoemulsification is the preferred technique for removing PPC. This review will provide methods to avoid and /or deal with intraocular surgical difficulties that can arise during emulsification. Employing these would result in least ocular morbidity and satisfactory visual outcomes for the patient. This is particularly relevant given the major advancements in technology and refinements in surgical techniques in phacoemulsification.

Role of T lymphocytes in renal disease in HIV-transgenic mice

The pathogenesis of human immunodeficiency virus (HIV)-associated focal segmental glomerulosclerosis (FSGS) has remained obscure. It has been proposed that renal parenchymal cells may be infected with HIV-1. If such infection occurs, the target cells would be expected to express viral proteins and thus could be targets for cytotoxic T lymphocytes. We previously described mice transgenic for a gag-pol-deleted HIV-1 genome that developed FSGS. In the present study, we tested the requirement for functional T cells in the evolution of renal disease in this model. We bred the HIV-transgenic mice (T26) with athymic nude mice to produce athymic T26 mice. We confirmed by flow cytometry of peripheral blood, thymus, lymph node, and spleen that the athymic T26 mice lacked mature T cells. The athymic T26 mice developed renal disease characterized by FSGS, tubular atrophy and dilatation, and interstitial infiltrate that was qualitatively identical to that seen in the parental T26 mice. Quantitative assessment of the athymic T26 mouse kidneys showed that glomerulosclerosis, tubular injury, and interstitial infiltrate were less severe compared with the parental T26 mouse kidneys. Although T26 mouse kidneys had a mixed cellular infiltrate composed of CD4 cells, CD8 cells, and macrophages, interstitial infiltrates within the athymic T26 mouse kidneys included macrophages but lacked both CD4 and CD8 cells. The renal expression of the HIV transgene was 1. 7-fold greater in T26 mice compared with athymic T26 mice. We conclude that mature T cells are not absolutely required for the development of HIV-associated nephropathy in transgenic mice but that, in their absence, renal disease is significantly milder. These data suggest that T-cell-mediated cytotoxicity directed against renal cells expressing virally encoded proteins is not an essential feature of renal pathogenesis in this model.

Increased mortality, blunted production of nitric oxide, and increased production of TNF-alpha in endotoxemic TGF-beta1 transgenic mice

The expression of the inducible isoform of nitric oxide synthase (NOS2, iNOS) is increased in patients undergoing sepsis as well as in animal models in which septic shock is induced by injection of bacterial lipopolysaccharide (LPS). Transforming growth factor-beta1 (TGF-beta1) potently suppresses NO production both in vitro and in vivo. After intraperitoneal injection of LPS, mice over-expressing a cDNA coding for active TGF-beta1 in the liver (Alb/ TGF-beta1) exhibited reduced serum levels of the NO reaction products NO2(-) + NO3(-) compared with controls. Paradoxically, while endotoxemic Alb/ TGF-beta1 mice expressed much less NOS2 protein in peritoneal exudate cells than did endotoxemic wild-type mice, Alb/TGF-beta1 mice expressed more NOS2 mRNA and protein in both liver and kidney. Alb/ TGF-beta1 mice treated with LPS had eightfold higher serum tumor necrosis factor alpha (TNF-alpha) levels and experienced increased mortality compared with wild-type mice, which was associated with renal insufficiency. These results suggest that renal dysfunction, decreased production of NO, and/or increased production of TNF-alpha are associated with increased mortality of endotoxemic Alb/TGF-beta1 mice.

Bricks as historical record of heavy metals fallout: Study on copper accumulation in Agra soils since 1910

Peat, ice deposits and aquatic sediments, which have been used as a geochemical monitor of atmospheric heavy metal pollution until now, are open and dynamic systems and can be easily affected by climatic variations. In contrast, bricks, which are more compact, can act as a better geochemical monitor. Analysis of Cu, Cr, Ni, Pb and Zn in scores of soil and brick (baked/unbaked) samples, collected from a large area in and around a rapidly growing Indian city, Agra, reveals approximately similar concentrations in soils and bricks, thereby showing insignificant fractionation of these metals during brick making. Further, metals concentration in the core of bricks remains unaffected by any significant amount of acidic and alkaline rain. Thus, the feasibility of a novel role of bricks as a geochemical monitor of atmospheric heavy metal pollution has been tested. Utilizing this concept, an attempt has also been made to trace the history of atmospheric copper depositions in the soils of Agra during the last 100 years.

Stimulation of endothelial cells by doses of basic FGF-saporin that are lethal to smooth muscle cells

Basic fibroblast growth factor (FGF) receptors are up-regulated in proliferating (vs. quiescent) aortic smooth muscle cells, according to the results of recent studies. This up-regulation allows the ribosome inactivator saporin (if linked to basic FGF) to enter and kill proliferating, but not quiescent smooth muscle cells in vitro and in vivo. The authors now report that endothelial cells exhibit a different response. In 10% serum, FGF-SAP (0.1-1 nM) stimulates protein synthesis and cell division in subconfluent endothelial cells, but inhibits protein synthesis and cell division in subconfluent smooth muscle cells. Endothelial cells were inhibited at 10 nM FGF-SAP. A stimulatory response was seen in smooth muscle cells only at 0.1 nM FGF-SAP, and only after serum deprivation. Both cell types were resistant to FGF-SAP at high cell density. These responses correlated with FGF receptor density, which was sixfold higher in smooth muscle than endothelial cells and twice as high in serum-free smooth muscle cells as in serum-deprived smooth muscle cells. Moreover, a dose of FGFSAP that inhibited neointimal smooth muscle accumulation after balloon injury did not inhibit reendothelialization. Thus, there is a dose range at which FGF-SAP has unique properties that may make it useful in the treatment of vascular injury.

Regulation of transforming growth factor-beta 1 and its receptor by cyclosporine in human T lymphocytes

Scarring, fibrosis, and immunosuppression occurs with chronic cyclosporine (CsA) administration. We postulated that CsA may induce transforming growth factor (TGF)-beta 1 secretion from human T lymphocytes, a cytokine with immunoregulatory effects that has been implicated in the pathogenesis of wound healing and scarring. TGF-beta 1 was measured in serum-free supernatants harvested from T lymphocytes stimulated in the presence of CsA by a specific sandwich ELISA. CsA (10-1000 ng/ml) enhanced TGF-beta 1 secretion by approximately 40-80% in a dose-dependent manner. Increased TGF-beta 1 secretion in the presence of CsA was accompanied by a 2- to 4-fold increase in TGF-beta 1 mRNA levels due to both enhancement of its nuclear transcription as well as prolongation of TGF-beta 1 mRNA half-life. To determine whether the increase in TGF-beta 1 secretion was also accompanied by a concomitant change in its receptor, TGF-beta 1 receptor expression was analyzed by cross-linking of radioiodinated TGF-beta 1. Unactivated T lymphocytes expressed both a 105-kDa and a 65-kDa TGF-beta receptor. Upon stimulation, a transient increase in receptor density was seen at 12 hr, followed by a decline at later time points. Cells treated with CsA exhibited at least 2-fold higher levels of TGF-beta receptors in a dose-dependent manner. Thus, CsA enhances the production of TGF-beta 1 protein as well as the expression of its receptor in activated T lymphocytes. Enhanced TGF-beta 1 production and binding may contribute to the immunosuppressive and fibrosis-promoting effects of CsA therapy.

Molecular cloning and expression of the acidic fibroblast growth factor receptors in a rat parathyroid cell line (PT-r). Parathyroid cell-specific calcium-dependent change of ligand accessibility and covalent attachment of heparan sulfate glycosaminoglycan to the receptors

We have previously identified two fibroblast growth factor (FGF) receptors with higher affinity for acidic FGF rather than basic FGF in a rat parathyroid cell line (PT-r). Carbohydrate analyses of the receptors suggested the presence of three different types of FGF receptors, a 150-kDa glycoprotein receptor, a approximately 150-kDa heparan sulfate-proteoglycan receptor, and a 130-kDa glycoprotein receptor (Sakaguchi, K., Yanagishita, M., Takeuchi, Y., and Aurbach, G.D. (1991) J. Biol. Chem. 266, 7270-7278). Here, we have cloned two isoforms of the FGF receptors from PT-r cells; one with two immunoglobulin (Ig)-like domains (clone a), and the other with an additional Ig-like domain and an acidic box (clone b). They showed highest homology to the mouse and human keratinocyte growth factor receptors among the FGF receptors reported. Clones a and b had one and three possible glycosaminoglycan attachment sites, respectively. Heparitinase treatment of PT-r cells transfected with clone a suggested that the protein for the 130-kDa glycoprotein receptor was encoded by clone a, and that the same protein also served as a core protein for the approximately 150-kDa heparan sulfate-proteoglycan receptor. Heparan sulfate glycosaminoglycan attachment to the 150-kDa receptor encoded by clone b was not detectable by the same enzyme treatment. Site-directed mutagenesis (from Ser to Ala) studies of the consensus sequence for the attachment of glycosaminoglycans further supported the presence of covalently attached heparan sulfate glycosaminoglycan in the approximately 150-kDa heparan sulfate-proteoglycan receptor. These receptors overexpressed in PT-r cells changed ligand accessibility or apparently translocated after changing extracellular calcium concentrations in a manner similar to the native receptors in PT-r cells (Sakaguchi, K. (1992) J. Biol. Chem. 267, 24554-24562), whereas those expressed in CHO-K1 or NIH/3T3 cells did not. These findings strongly suggest that the two FGF receptor isoforms cloned here represent the acidic FGF receptors that we reported earlier. A subpopulation of the receptors carries heparan sulfate glycosaminoglycan covalently attached to the core protein, and the change in ligand accessibility in response to the shift in ambient calcium concentration is specific to the parathyroid cells.

Effects of acidic fibroblast growth factor on normal and ischemic myocardium

We sought to determine the effects of acidic fibroblast growth factor (FGF) on ischemic and normal myocardium and to determine whether direct application of acidic FGF to the heart could promote angiogenesis. Eighteen dogs underwent placement of an ameroid constrictor on the left anterior descending coronary artery (LAD). Three weeks later, a left internal mammary artery (IMA) pedicle was positioned over the LAD territory, with a sponge saturated with acidic FGF (n = 12) or saline (n = 4) interposed between the pedicle and the heart. Polytetrafluoroethylene fiber or collagen I sponges were used to deliver the acidic FGF. Weekly angiography of the IMA was performed in all dogs, but significant IMA to coronary collaterals were not demonstrable in any dog. Eight dogs had histological evidence of subendocardial infarction in the LAD territory (five acidic FGF, three control, p = NS). Striking smooth muscle cell hyperplasia was present in arterioles and small arteries exclusively in areas of subendocardial infarction in all of the acidic FGF-treated dogs but in none of the control dogs (p less than 0.05). Noninfarcted myocardium appeared normal in all dogs. In two additional dogs, ameroid constrictors were not placed on the LAD, such that acidic FGF-treated sponges were placed on normally perfused myocardium of the LAD territory. Histological evaluation of those hearts revealed normal myocardium, without evidence of myocardial infarction or smooth muscle cell hyperplasia. Thus, when acidic FGF is delivered to the myocardium via an epicardial sponge in dogs whose coronary flow is compromised, acidic FGF does not cause an angiogenic response in viable myocardium but causes vascular smooth muscle cell hyperplasia in areas subjected to ischemic injury.

Culture-induced increase in acidic and basic fibroblast growth factor activities and their association with the nuclei of vascular endothelial and smooth muscle cells

The activity of acidic and basic fibroblast growth factor-like mitogens (aFGF, bFGF) extracted from cultured bovine aortic endothelial (BAEC) and rat aortic smooth muscle cells (SMC) was compared with that of freshly isolated cells from the same tissues. Extracts of subendothelial extracellular matrix (ECM) and cell lysates of cultured BAEC contained 4-fold more bFGF-like activity than the extracts of fresh cells. ECM and cell lysates of SMC yielded 10-fold more bFGF-like activity than the fresh cell lysates. We consistently find aFGF-like activity in both cell types. In the case of BAEC, cultured cells and ECM contained 3-fold more aFGF-like activity when compared with freshly isolated cells, whereas in cultured SMC, aFGF-like activity in cell and ECM extracts was 8-fold higher than in fresh cell extracts. The mitogens extracted from cell lysates and from the ECM are closely related to aFGF or bFGF by the criteria that they bind to heparin-sepharose and elute at 1.1 M (aFGF) or 1.5 M (bFGF) NaCl, have molecular weights of about 18,000, and react with anti-aFGF (1.1 M), or anti-bFGF (1.5 M) antibodies when analyzed by Western blots and by radioimmunoassay specific for aFGF and bFGF. This mitogenic activity is inhibited by neutralizing antibodies to aFGF and bFGF. In addition, the column fractions are potent mitogens for Balb/c 3T3 fibroblasts. Acidic and basic FGF-like mitogenic activity could also be extracted from the cell nuclei. The subcellular localization of both FGFs was visualized in both nuclei and cytoplasm with immunoperoxidase. Compared with primary SMC, secondary SMC had an increased capacity to bind 125IaFGF to high affinity receptors, while binding to freshly isolated BAEC and SMC was negligible. We conclude that FGFs are present at low levels in freshly isolated cells and that propagation in cell culture provides a stimulus for production of these mitogens.

Innovations that influence the pharmacology of monoclonal antibody guided tumor targeting

Tumor targeting by monoclonal antibodies (MAbs) can be enhanced by (a) increasing the percentage of injected dose taken up by the tumor and/or (b) increasing the tumor:nontumor ratios. Several groups have demonstrated that one can increase tumor to nontumor ratios by the use of antibody fragments or the administration of second antibodies. Several other modalities are also possible: (a) the use of recombinant interferons to up-regulate the expression of specific tumor associated antigens such as carcinoembryonic antigen or TAG-72 on the surface of carcinoma cells and thus increase MAb tumor binding has proved successful in both in vitro and in vivo studies; (b) the intracavitary administration of MAbs. Recent studies have demonstrated that when radiolabeled B72.3 is administered i.p. to patients with carcinoma of the peritoneal cavity, it localizes tumor masses with greater efficiency than does concurrent i.v. administered antibody. Studies involving the comparative pharmacology of intracavitary administration of radiolabeled MAb in patients and several animal models will be discussed; (c) it has been reported that prior exposure of hepatoma to external beam radiation will increase radiolabeled MAb tumor targeting. We and others have not been able to duplicate this phenomenon with a human colon cancer xenograft model and radiolabeled MAbs to two different colon carcinoma associated antigens. The possible reasons for these differences will be discussed; (d) the cloning and expression of recombinant MAbs with human constant regions and subsequent size modification constructs will also undoubtedly alter the pharmacology of MAb tumor binding in both diagnostic and therapeutic applications.

A comparison using tissue electrical properties and temperature rise to determine relative absorption of microwave power in malignant tissue

This paper compares two methods for determining the radio frequency absorbed power in tissue: from the measured electrical properties of the tissue, and from the induced temperature rise per unit time. In previous research, we measured the ratio frequency electrical properties of muscle, mammary gland, and malignant mammary tissue (SMT-2A mammary adenocarcinoma) in female W/Fu isogeneic rats. From those measurements we calculated for each tissue the power absorption versus frequency, and formed the ratio of malignant-to-normal power absorption. This ratio exhibited a peak within the 150 to 400 MHz range, indicating a selective absorption of power in this type of malignant tissue over that of the normal host tissue. In the present study, by an entirely different method, we have directly tested the results of our earlier research. We filled a 20-cm-long section of rigid coaxial line (ordinarily air filled) with either normal (beef muscle or fat) or malignant (SMT-2A) tissue, and measured the temperature increase versus time at the irradiated tissue surface for the same absorbed power in each tissue type. We made the measurements from 50 to 915 MHz, and found that the initial temperature increase per second per watt absorbed (dT/dt/Pa) was greater in malignant tissue than in muscle or fat at each frequency tested, with the greatest differences occurring below 450 MHz. Power absorption based on the measured values of dT/dt/Pa was again greatest for the malignant tissue (SMT-2A mammary adenocarcinoma) within the 150 to 400 MHz range.

Fibroblast growth factors are present in adult cardiac myocytes, in vivo [corrected and issued with original paging in Biochem Biophys Res Commun 1988 Dec 30;157(3)]

We have previously shown that the adult heart contains mitogens immunologically identical to acidic and basic fibroblast growth factors. To determine whether these proteins are present in myocytes, we subjected lysates of freshly isolated myocytes to heparin-affinity chromatography. The 1.1 M - 3 M NaCl eluates stimulated incorporation of thymidine into DNA in quiescent Balb/c 3T3 fibroblasts, caused proliferation of vascular endothelial cells, and cross-reacted with antisera raised against acidic (1.1 M) and basic FGF's (1.5 M) by Western blotting and by RIA. These proteins may be involved in cellular differentiation and proliferation and may play an important role in regenerative and repair processes in the heart.

Studies concerning the effect of external irradiation on localization of radiolabeled monoclonal antibody B72.3 to human colon carcinoma xenografts

Recent studies in animal models involving antibody tumor targeting of hepatoma and melanoma and clinical trials involving hepatoma patients have suggested that preirradiation of tumors may enhance antibody tumor targeting. These reports led us to study the effect of external irradiation on monoclonal antibody (MAb) targeting of human carcinomas; as a model system, we used MAb B72.3 and the LS-174T human colon carcinoma xenograft in athymic mice. LS-174T tumors exposed to 300 cGy grew to approximately 93% the size of non-irradiated tumors, while those exposed to 600, 900, or 2,000 cGy were approximately 41% the size of control tumors. Splitting the 900 cGy into three 300-cGy fractions yielded a two-fold lower tumor volume compared with a single 900-cGy fraction. Histochemical evaluation of the carcinomas revealed a decrease in the number of mitoses per high power field consistent with early effects of radiation exposure. Using the avidin-biotin complex immunoperoxidase technique, carcinomas were assayed for expression of the tumor associated glycoprotein (TAG)-72, the high-molecular-weight mucin detected by MAb B72.3. No discernable variation was observed in the staining intensity among tumors in both the control and radiation treated group; that is, differences among tumors within each group were compatible with the known heterogeneous expression of TAG-72. Exposure of carcinomas to 300 or 900 cGy in a single fraction or 900 cGy split in three 300-cGy fractions did not yield a consistent or substantial enhanced localization of radiolabeled MAb B72.3 IgG or F(ab')2 to tumors. A 1.5-fold augmentation of MAb binding to tumors was observed in preirradiated mice; however, these results were not statistically significant. Inherent differences in tumors such as cell type of origin, size, spatial configuration, extent of vascularization and volume of interstitial space may contribute to variability of the effect of preirradiation of tumors on antibody binding. Our results suggest that consistent augmentation of radiolabeled antibody localization to tumors is not a universal phenomenon.

Effect of 5-hydroxytryptamine on tissue blood flow and microwave heating of rat tumors

We have investigated the effect of 5-hydroxytryptamine (5-HT) on SMT-2A mammary adenocarcinoma blood flow during localized microwave hyperthermia treatment. Tissue blood flow in isogeneic female W/Fu rats was estimated using 25-micron-diameter 113Sn-labeled microspheres. An intraarterial injection of 5-HT (1 mg/kg) into either conscious or anesthetized (Nembutal, 20 mg/kg) animals resulted in a 53% reduction in tumor blood flow, while that of the surrounding skeletal muscle remained unchanged. Because of the selective reduction in tumor perfusion, the blood flow of the normal and malignant tissue was equal after 5-HT injection. This blood flow equivalence remained unaltered after 45 min of heating at 42 degrees C. Consequently, the temperature in the tumor was not significantly different from that in the surrounding normal tissue. In contrast, when the tissues were heated at 42 degrees C without 5-HT, the tumor blood flow was significantly greater than that in the surrounding musculature, resulting in the tumor being 1 degree C lower than the muscle temperature. An intratumoral injection of 5-HT (0.25 mg) reduced the tumor blood flow by 92%, and the blood flow of the surrounding muscle was reduced by 57%. These tissue blood flows were not significantly altered by heating at 44 degrees C for 45 min, and the tumor temperature was 0.7 degrees C greater than that in the muscle. When heating at 44 degrees C was performed without 5-HT injection, the tissue temperatures were equal. Thus, both an intraarterial and an intratumoral injection of 5-HT prior to hyperthermia treatment significantly improved the temperature differential between the neoplastic and surrounding normal tissue. Of additional interest was the observation that an intratumoral injection of 0.15 M NaCl also resulted in a preferential increase in the tumor temperature.

Blood flow to primary tumors and lymph node metastases in SMT-2A tumor-bearing rats following intravenous flunarizine

Tumor blood flow is an important determinant of the efficacy of presently available antineoplastic treatment modalities. Using 113Sn-labeled microspheres, 25 micron in diameter, we measured blood flow to primary tumors and regional lymph node metastases in conscious SMT-2A mammary adenocarcinoma-bearing syngeneic rats following a single i.v. bolus injection of the calcium entry blocker, flunarizine. Tumor blood flow increased in a biphasic dose-dependent fashion; at a dose of 1 mg/kg, primary tumor blood flow increased approximately 50% (p less than 0.001) without a significant change in heart rate or blood pressure. The increase in flow was distributed to both the peripheral viable and central necrotic regions of the tumor and was still detectable 45 min following administration of the drug. A similar increase in blood flow was demonstrated for lymph node metastases (p less than 0.001).

Microwave hyperthermia and its effect on tumor blood flow in rats

The present experiments were designed to investigate the effects of microwave hyperthermia on the microcirculation of normal and malignant tissues in female Wistar/Furth rats. During the localized heating of anesthetized rats, the hind leg musculature surrounding the SMT-2A mammary adenocarcinoma was heated at either 39 degrees, 42 degrees, or 44 degrees. Neither the body temperature, cardiac output, heart rate, nor systemic arterial pressure were significantly altered by heating at these temperatures for up to 60 min. Our results demonstrate that the changes in vascular resistance which occur during hyperthermic treatment are dependent upon both the temperature and the tissue heated. When the tumor (1.2 g)-bearing hind leg was heated to 39 degrees, the tissue vascular resistance and blood flow were unaltered even after 45 min of heating. Heating at 42 degrees and 44 degrees caused an initial vasoconstriction in the tumor, which was subsequently followed by marked vasodilation. This transient initial decrease in blood flow was not, however, observed in the skeletal muscle at either temperature. With prolonged heating at 42 degrees and 44 degrees, the muscle blood flow increased by a factor of 1.6 and 3.2, respectively. In contrast, malignant tissue blood flow increased by a factor of 1.3, and this maximum increase was observed only when the tumor was heated at 44 degrees for more than 45 min. Nevertheless, even with this proportionally greater increase in the blood flow of the surrounding normal tissue, it was never more than that of the tumor. As a consequence, the tumor temperature during hyperthermic treatment was always either less than or equal to that in the surrounding normal musculature.

Effect of verapamil on malignant tissue blood flow in SMT-2A tumor-bearing rats

We investigated the influence of the calcium antagonist verapamil on malignant and normal tissue blood flow using 25-micrometer 113Sn-labeled microspheres. Isogeneic Wistar-Furth rats were inoculated with a metastasizing mammary gland adenocarcinoma (SMT-2A) in the hindlimb musculature and mammary gland. Verapamil was administered as an i.v. bolus via an external jugular vein catheter followed by a supplemental constant infusion with a Harvard infusion pump. Plasma verapamil levels were determined by high performance liquid chromatography, and heart rate and systemic blood pressure were monitored. Verapamil in concentrations of 100 to 200 ng/ml resulted in an approximate 50% increase in tumor blood flow compared to control levels (p less than 0.001) regardless of the site of tumor implantation. These levels were not associated with a significant alteration in arterial blood pressure. These data suggest that verapamil in concentrations currently used in humans may provide a means of improving the delivery of chemotherapeutic agents to solid neoplasms and may also enhance the effectiveness of ionizing radiation treatment by increasing tumor oxygenation.

Establishment and characterization of a cell line (SS78) from a human renal cell carcinoma

A new cell line, SS78, was established from a primary renal cell carcinoma of a Caucasian male. The tissue was dispersed with collagenase, and viable cells were separated by flotation on a Ficoll-Hypaque gradient. In culture, the SS78 cells retained a distinct epithelial morphology, and no fibroblast like cells were seen. The cultured cells were aneuploid with a modal chromosome number of 80 and had several marker chromosomes. Inoculation of the cultured cells into athymic nude mice caused tumors at the sites of inoculation.

In vitro chemotherapeutic testing of urologic tumors

We studied 20 transitional cell tumors of the bladder and 25 adenocarcinomas of the kidney in vitro to determine their chemotherapeutic sensitivity. The different sensitivity patterns among the individual tumors were demonstrated. Identical drug sensitivity patterns could be identified in the primary and metastatic sites, and in tumor tissue removed from the primary and metastatic deposits in the same patient. Human renal adenocarcinoma maintained in the athymic mouse demonstrated identical chemotherapeutic sensitivity patterns in vitro and in vivo. Our data would support that these in vitro chemotherapy studies may assist in the selection of agents to use in human tumor-bearing hosts.

An in vitro assay procedure to test chemotherapeutic drugs on cells from human solid tumors

An in vitro assay was developed to measure the chemotherapeutic drug susceptibility of cells from human tumors. The assay utilized live cells, freshly isolated from tumor tissue, which were incubated for a short period in vitro. The drug-induced inhibition of incorporation of radiolabeled precursor into DNA, RNA, and protein was measured. The assay is sensitive to concentrations of chemotherapeutic drugs in the therapeutic range and is reproducible when tested with replicates of the same tumor cell population.

Activation of cyclophosphamide for in vitro testing of cell sensitivity

Two methods are described for the activation of cyclophosphamide by a liver microsome preparation. These procedures were applicable to an assay in vitro which tests the sensitivity of tumor cells to the drug. Satisfactory results were obtained either by pretreatment of the cyclophosphamide and removal of the microsomes before testing or by the somewhat simpler procedure of mixing drug, microsomes, and test cells for the assay. Microsome treatment of bleomycin gave a smaller increase in activity, and much smaller effects were seen on some other drugs.

In vitro chemotherapy testing of transitional cell carcinoma

The chemotherapeutic drug sensitivity of live cells freshly isolated from two human bladder tumors was studied. Substantial differences in the sensitivities of the two tumors to various chemotherapeutic drugs as well as different sensitivities of a given tumor to different drugs were found. Such data could be valuable clinically. The therapeutic value of cyclophosphamide, thiotepa and methotrexate was questionable for these two tumors because an increase in thymidine incorporation was seen after treatment with these drugs. A similar increase was observed after treatment with 5-fluorouracil in cells of a tissue-culture cell line derived from a human bladder tumor. Pretreatment of the cells with 5-fluorouracil reduced this effect. Even after 12 to 18 hours of exposure to 5-fluorouracil, the cells formed a confluent monolayer within 9 days. A similar treatment with doxorubicin hydrochloride resulted in detachment of the cells and formation of aggregates. The aggregated cells excluded trypan blue for at least 9 days after the doxorubicin hydrochloride was removed.