Histone deacetylase interacts directly with DNA topoisomerase II.

Histone deacetylases (HDACs) modify nucleosomal histones, have a key role in the regulation of gene transcription, and may be involved in cell-cycle regulation, differentiation and human cancer. Purified recombinant human HDAC1 protein was used to screen a cDNA expression library, and one of the clones identified encoded DNA topoisomerase II (Topo II), an enzyme known to have a role in transcriptional regulation and chromatin organization. Coimmunoprecipitation experiments indicate that HDAC1 and HDAC2 are associated with Topo II in vivo under normal physiological conditions. Complexes containing Topo II possess HDAC activities, and complexes containing HDAC1 or HDAC2 possess Topo II activities. HDAC and Topo II modify each other's activity in vitro and in vivo. Our results indicate the existence of a functionally coupled complex between these two enzymes and offer insights into the potential mechanisms of action of both enzymes.

Involvement of the cyclic-AMP-dependent protein kinase A pathway in thyroxine effects on calcitonin secretion from TT cells.

Previous studies have demonstrated that plasma calcitonin is lower in hypothyroid patients and that thyroxine stimulates the human thyroid to release calcitonin. Therefore, thyroid hormones may regulate the secretion of calcitonin, but further work is needed to address this possibility in more detail. TT cells, a model of human thyroid C cells, were incubated in a medium containing vehicle, thyroxine, or thyroxine methyl-hemisuccinate-bovine serum albumin (BSA-L-T(4), thyroxine was immobilized and linked to BSA); then, the levels of secreted calcitonin (hCT), calcitonin mRNA, and cAMP were measured. To study links that connect the cAMP-dependent protein kinase A (PKA) pathway to the observed thyroxine effects, cells were treated with either vehicle or thyroxine plus SQ22536 [an adenylyl cyclase (AC) inhibitor], KT5720 (a PKA inhibitor), or 3-isobutyl-1-methylxanthine (IBMX, a phosphodiesterase inhibitor). The activity levels of AC and PKA, and secreted calcitonin were then measured. The results indicate that thyroxine increases calcitonin secretion, cellular cAMP accumulation, and the activities of AC and PKA, but does not increase hCT mRNA levels in TT cells. BSA-L-T(4) also increases calcitonin secretion. These effects are inhibited by SQ22536, and KT5720 and suggest that the nongenomic thyroxine effects that stimulate calcitonin secretion from TT cells involve the cAMP-dependent PKA pathway.

Effects of Exercise Alone or in Combination with High-Protein Diet on Muscle Function, Aerobic Capacity, and Physical Function in Middle-Aged Obese Adults: A Randomized Controlled Trial.

BACKGROUND: Obesity accelerates and exacerbates the age-related changes on muscle function and exercise capacity. In addition, the middle-aged population is often overlooked when talking about the prevention of sarcopenia. This study investigated the effects of exercise alone or in combination with a high-protein diet on muscle function and physical fitness in middle-aged obese adults. MATERIALS AND METHODS: Sixty-nine middle-aged (50-64 years old) obese adults were randomly assigned to one of the following groups: control group (C; n=23), exercise group (E; n=23) or exercise plus high-protein group (EP; n=23). Individuals within the E and EP groups received 12 weeks of exercise training; whereas, the individuals in the EP group also received a high-protein diet intervention (1.6g/kg/day). Individuals within the C group were asked to maintain their lifestyle for 12 weeks. Participants were evaluated before and after the intervention. Outcome measures included maximal exercise capacity, muscle function and functional physical performance. Analysis of covariance was used to determine the effects of the intervention. RESULTS: After the intervention, the E and EP groups had greater maximal work rate, peak oxygen consumption, and muscle power during muscle contractions at 180°/sec than that in the C group (P<0.05). The EP group, but not the E group, showed significant improvement in the sit-to-stand test and climbing stairs test than the C group after the intervention (P<0.05). Within group comparisons showed that the anaerobic threshold only increased in the EP group (+12% from pre-test). CONCLUSIONS: For middle-aged obese adults, exercise with a high-protein diet not only improved muscle power and exercise capacity but also enhanced their functional physical performance.

Host control of tumor growth.

A humoral factor (molecular weight less than 60,000) that was present in the ascitic fluid of mice bearing intraperitoneal tumors and in pleural effusions from human cancer patients was found to promote the growth of a murine tumor and to suppress cell-mediated tumor immunity. However, the hosts that had recovered from the immunosuppressive state produced a serum factor that could neutralize the immunosuppressive effect.

Activation of Escherichia coli heat-labile enterotoxins by native and recombinant adenosine diphosphate-ribosylation factors, 20-kD guanine nucleotide-binding proteins.

Escherichia coli heat-labile enterotoxins (LT) are responsible in part for "traveler's diarrhea" and related diarrheal illnesses. The family of LTs comprises two serogroups termed LT-I and LT-II; each serogroup includes two or more antigenic variants. The effects of LTs result from ADP ribosylation of Gs alpha, a stimulatory component of adenylyl cyclase; the mechanism of action is identical to that of cholera toxin (CT). The ADP-ribosyltransferase activity of CT is enhanced by 20-kD guanine nucleotide-binding proteins, known as ADP-ribosylation factors or ARFs. These proteins directly activate the CTA1 catalytic unit and stimulate its ADP ribosylation of Gs alpha, other proteins, and simple guanidino compounds (e.g., agmatine). Because of the similarities between CT and LTs, we investigated the effects of purified bovine brain ARF and a recombinant form of bovine ARF synthesized in Escherichia coli on LT activity. ARF enhanced the LT-I-, LT-IIa-, and LT-IIb-catalyzed ADP ribosylation of agmatine, as well as the auto-ADP ribosylation of the toxin catalytic unit. Stimulation of ADP-ribosylagmatine formation by LTs and CT in the presence of ARF was GTP dependent and enhanced by sodium dodecyl sulfate. With agmatine as substrate, LT-IIa and LT-IIb exhibited less than 1% the activity of CT and LT-Ih. CT and LTs catalyzed ADP-ribosyl-Gs alpha formation in a reaction dependent on ARF, GTP, and dimyristoyl phosphatidylcholine/cholate. With Gs alpha as substrate, the ADP-ribosyltransferase activities of the toxins were similar, although CT and LT-Ih appeared to be slightly more active than LT-IIa and LT-IIb. Thus, LT-IIa and LT-IIb appear to differ somewhat from CT and LT-Ih in substrate specificity. Responsiveness to stimulation by ARF, GTP, and phospholipid/detergent as well as the specificity of ADP-ribosyltransferase activity are functions of LTs from serogroups LT-I and LT-II that are shared with CT.

RBP1 recruits the mSIN3-histone deacetylase complex to the pocket of retinoblastoma tumor suppressor family proteins found in limited discrete regions of the nucleus at growth arrest.

Retinoblastoma (RB) tumor suppressor family pocket proteins induce cell cycle arrest by repressing transcription of E2F-regulated genes through both histone deacetylase (HDAC)-dependent and -independent mechanisms. In this study we have identified a stable complex that accounts for the recruitment of both repression activities to the pocket. One component of this complex is RBP1, a known pocket-binding protein that exhibits both HDAC-dependent and -independent repression functions. RB family proteins were shown to associate via the pocket with previously identified mSIN3-SAP30-HDAC complexes containing exclusively class I HDACs. Such enzymes do not interact directly with RB family proteins but rather utilize RBP1 to target the pocket. This mechanism was shown to account for the majority of RB-associated HDAC activity. We also show that in quiescent normal human cells this entire RBP1-mSIN3-SAP30-HDAC complex colocalizes with both RB family members and E2F4 in a limited number of discrete regions of the nucleus that in other studies have been shown to represent the initial origins of DNA replication following growth stimulation. These results suggest that RB family members, at least in part, drive exit from the cell cycle by recruitment of this HDAC complex via RBP1 to repress transcription from E2F-dependent promoters and possibly to alter chromatin structure at DNA origins.

Coexpression of mutant p53 and p193 renders embryonic stem cell-derived cardiomyocytes responsive to the growth-promoting activities of adenoviral E1A.

Expression of adenoviral E1A in cardiomyocytes results in the activation of DNA synthesis followed by apoptosis. In contrast, expression of simian virus 40 large T antigen induces sustained cardiomyocyte proliferation. Previous studies have shown that T antigen binds to 2 proapoptotic proteins in cardiomyocytes, namely the p53 tumor suppressor and p193 (a new member of the BH3-only proapoptosis subfamily). Structure-function analyses identified a p193 C-terminal truncation mutant that encodes prosurvival activity. This mutant was used to test the role of p193 in E1A-induced cardiomyocyte apoptosis. E1A induced apoptosis in cardiomyocytes derived from differentiating embryonic stem cells. Expression of the prosurvival p193 mutant alone or a mutant p53 alone did not block E1A-induced apoptosis. In contrast, combinatorial expression of mutant p193 and mutant p53 blocked E1A-induced apoptosis, resulting in a proliferative response indistinguishable from that seen with T antigen. These results confirm the hypothesis that there are 2 proapoptotic pathways, encoded by p53 and p193, respectively, which restrict cardiomyocyte cell cycle activity in differentiating embryonic stem cell cultures. Furthermore, these results explain in molecular terms the phenotypic differences of E1A versus T-antigen gene transfer in cardiomyocytes.

Modulation of cell proliferation by human recombinant interleukin-1 and immune interferon.

The growth-modulating effects of recombinant alpha- and beta-forms of human interleukin-1 (IL-1) and interferon-gamma (IFN-gamma) were examined with several human cell lines. Exposure to combinations of IL-1 and IFN-gamma resulted in three categories of cell response. The first was cell lines in which IL-1 stimulated growth and offset the growth inhibitory effects of IFN-gamma. These lines included the lung carcinoma CALU-1 and the colon carcinoma SW-48. The second was some of the cell lines that were refractory to IL-1 and that were inhibited by IFN-gamma alone. These included the cervical carcinoma HeLa, the transformed milk line HBL-100, and the myelogenous leukemia K562. The third group consisted of cells in which growth inhibition by IL-1 and IFN-gamma was additive. These included the mammary carcinomas MCF-7 and MDA-MB-415. The exception to this latter group was ME-180 in which significant additive inhibitory effects could not be demonstrated. IL-1 alone primarily induced a cytostatic effect in growth-inhibited cell lines. The cytolytic effect induced by IFN-gamma was increased in the presence of IL-1. The data support the conclusion that the effects on growth of IL-1 and IFN-gamma are mediated by different mechanisms.

Induction of antitumor immunity by interleukin-2 gene-transduced mouse mammary tumor cells versus transduced mammary stromal fibroblasts.

BACKGROUND: Tumor cell-targeted cytokine gene transfer has been used to generate tumor cell vaccines, but this approach is limited by the need to establish and implant live tumor cells. PURPOSE: The purpose of this study was to determine if stromal fibroblasts could be used as an alternative vehicle for delivery of the cytokine interleukin-2 (IL-2) into the tumor microenvironment. We attempted to establish the feasibility of (a) genetic immunotherapy in a mammary tumor system and (b) engineering stromal fibroblasts as well as tumor cells. We compared the effects of tumor cell-mediated and stromal fibroblast-mediated local IL-2 expression on the generation of antitumor immune responses. METHODS: Retroviral vectors containing a human IL-2 gene were used to transduce a mouse mammary tumor line, 4TO7, and an immortalized but nontumorigenic fibroblast line established from syngeneic mammary fatpads. Expression of the IL-2 gene in transduced cells was determined by measuring IL-2 secretion, by RNA-polymerase chain reaction, and by immunochemistry. Groups of 5-12 BALB/c mice were injected with either 4TO7 cells or various doses of IL-2-secreting 4TO7 cells (4TO7-IL-2); tumor growth was monitored. To test whether local IL-2 expression by transduced cells could influence the growth of unmodified tumor cells, we determined tumor development in groups of mice treated with 4TO7 cells co-injected with either 4TO7-IL-2 cells or IL-2-secreting fibroblasts. RESULTS: 4TO7-IL-2 cells induced active immunity able to reject the immunizing tumor and to resist challenge with parental 4TO7 cells on the contralateral side. Mice pretreated with 4TO7-IL-2 were significantly protected compared with untreated control animals or mice pretreated with irradiated 4TO7 cells. The immunity induced by 4TO7-IL-2 cells did not protect against challenge with another subline, 4T1, which was derived from the same spontaneously arising mammary tumor as 4TO7. Co-injection of 4TO7 cells with 4TO7-IL-2 cells reduced tumorigenicity, whereas co-injection of 4TO7 cells with IL-2 secreting fibroblasts did not. CONCLUSION: Our results suggest that induction of anti-tumor immune response by local IL-2 production is most effective when the helper cytokine is secreted by the tumor cell. IMPLICATION: Our studies caution against the use of IL-2 gene-transduced syngeneic stromal cells as an alternative strategy of gene therapy for cancer. However, they may allow study of the mechanisms of tumor antigen recognition and the possible involvement of co-stimulatory signals for effective tumor vaccination by gene-modified cells.

Lymphocyte-activating and growth-inhibitory activities for several sources of native and recombinant interleukin 1.

Several native and recombinant forms of human interleukin-1 (IL-1) and recombinant murine IL-1 were assayed for their ability to inhibit the growth of cell lines established from malignant and nonmalignant human sources. The amount of growth-inhibitory activity was compared to the units of half-maximal [3H]thymidine incorporation in mouse thymocyte cultures exposed to IL-1. Three malignant human mammary cell lines (MCF-7, T47D, and MDA-MB-415) were growth inhibited in the presence of both native and the alpha and beta forms of recombinant human IL-1. MDA-MB-415 was most sensitive. Although most sources of IL-1 showed good correlation between units of activity and percentage of growth inhibition, native IL-1 from Genzyme Corporation induced a cytotoxic effect. Murine IL-1 was less growth inhibitory than the human forms of the monokine. Human embryonic lung (HEL), adult fibroblast (CRL 1445), and transformed milk (HBL-100) lines were not growth inhibited when tested against any IL-1 source. A lung carcinoma (CALU-1) and a colon carcinoma (SW-48) were not inhibited by either the alpha or beta forms of human recombinant IL-1.

Inhibition of cell proliferation by interleukin-1 derived from monocytic leukemia cells.

Growth inhibitors and interleukin-1 (IL-1) are two biological response modifiers produced by mezerein-treated THP-1 cells maintained in serum-free medium. The activities comigrated with isoelectrofocusing in a pH range of 6.7 to 7.3. Subsequent molecular sieving on an AcA-54 column revealed that a portion of the growth-inhibitory activity for the mammary cell line MCF-7 remained associated with IL-1. IL-1-containing fractions were further analyzed by chromatography with DEAE-Sephacel, phenyl:Sepharose, and concanavalin A:Sepharose. In each instance, IL-1 coeluted with growth-inhibitory activity. IL-1 and growth-inhibitory activities partially purified by sequential isofocusing, AcA-54 chromatography, and DEAE-Sephacel were located in a single region following preparative polyacrylamide gel electrophoresis. Elution, concentration, and analytical polyacrylamide gel electrophoresis of this region resulted in a single band with an apparent molecular weight of 17,000. Stability studies revealed similarities between the IL-1 activity and growth-inhibitory activity in their sensitivity to a variety of physical and chemical treatments. A commercial source of human IL-1 also inhibited the growth of MCF-7 cells. DEAE-purified IL-1 derived from THP-1 cells inhibited the growth of 7 of 11 cell types tested, and all inhibited cell lines were established from malignant sources. Prostaglandin synthesis by MCF-7 cells in response to IL-1 was not responsible for growth inhibition.

Correlation between human cell growth response to interleukin 1 and receptor binding.

Human recombinant interleukin 1 alpha (IL-1 alpha) and IL-1 beta inhibited the replication of the mammary tumor cell line, MDA-MB-415; stimulated division in the colon carcinoma, SW-48; and had no effect on the growth of the milk mammary line, HBL-100. Inhibition of growth was reflected in a significant decrease in DNA synthesis accompanying a transient increase in RNA synthesis. Specific binding of 125I-labeled recombinant IL-1 beta by MDA-MB-415 and SW-48 reached a maximum by 2 h of incubation, and an equivalent amount was bound by each cell type. Binding was inhibited in a dose-dependent manner by unlabeled IL-1 alpha or IL-1 beta. Scatchard plot analysis revealed that MDA-MB-415 cells expressed approximately 700 binding sites with an apparent dissociation constant of 8.8 x 10(-10) M. Reversibility of growth inhibition was independent of dose or time of incubation, but DNA synthesis did not return to control values. Flow cytometric analysis of DNA content showed that growth inhibition was cell cycle phase nonspecific with a slight reduction in the proportion of cells in S phase. The major conclusion from these studies was that inhibition or stimulation of malignant cell growth by IL-1 was related to the presence of receptor sites.

Production of growth-inhibitory activity in serum-free medium by human monocytic leukemia cells.

Serum-free medium conditioned by activated cells of the acute monocytic leukemia line, THP-1, was examined for growth-inhibitory activity with several established human cell lines. Free-floating clusters of THP-1 cells were activated into adherent nonproliferating cells by a 24-hr exposure to 10(-7) M mezerein in Roswell Park Memorial Institute 1640 medium containing 1% fetal bovine serum. Adherent cells were incubated for an additional 24 hr in serum-free medium containing insulin (5 micrograms/ml). Dose-response studies revealed that a cervical carcinoma (HeLa), a melanoma (A375Ag5), and several mammary carcinoma cell lines (MCF-7, BT474, MDA-MB415, and T47D) were growth inhibited by this conditioned medium. We concluded, from the results of thymidine release assays and from experiments on reversibility, that inhibition was a cytostatic and not a cytolytic response. In contrast, THP-1 conditioned medium stimulated the growth of two mammary lines (ZR75-1 and HBL-100), a lung type II carcinoma (549), and a colon adenocarcinoma (SW48). Preliminary characterization showed that the inhibitory activity was stable to acid and urea treatment but was destroyed by trypsin and sodium dodecyl sulfate. Molecular sieve chromatography of acetic acid-extracted material separated the inhibitory and stimulatory components.

P-Glycoprotein and multidrug resistance-related protein expressions in relation to technetium-99m methoxyisobutylisonitrile scintimammography findings.

The purpose of this study was to retrospectively study 48 patients with infiltrating ductal breast cancer to evaluate the relationship between the degree of accumulation of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) and P-glycoprotein (Pgp) or multidrug resistance-related protein (MRP) expression in breast cancer tissues. Before surgery or biopsy, all 48 patients underwent scintimammography started 10 min after the injection of Tc-MIBI. Tumor:background (T:B) ratios were calculated from the Tc-MIBI scintimammography. Immunohistochemical analysis was performed on the pathological specimens of the 48 breast tumors to determine Pgp and MRP expression. According to the results of immunohistochemical analysis, the 48 breast cancers were separated into four groups: (a) group 1, 12 cancers with both positive Pgp expression and positive MRP expression; (b) group 2, 12 cancers with positive Pgp expression and negative MRP expression; (c) group 3, 12 cancers with negative Pgp expression and positive MRP expression; and (d) group 4, 12 cancers with both negative Pgp expression and negative MRP expression. Among the four groups, the T:B ratio was lowest in group 1 (1.13+/-0.10) and highest in group 4 (2.17+/-0.14), respectively (P < 0.05). The T:B ratios of groups 2 (1.30+/-0.25) and 3 (1.32+/-0.26) were between those of groups 1 and 4. Our data confirmed that Tc-MIBI scintimammography is useful for determining Pgp and MRP expression in patients with breast cancers.

Ketorolac Tromethamine Spray Prevents Postendotracheal-Intubation-Induced Sore Throat after General Anesthesia.

Background. Postoperative sore throat is one of the major complaints of general anesthesia in the postanesthesia care unit. This prospective study investigated the preventive effect of ketorolac tromethamine spray in postendotracheal-intubation-induced sore throat after general anesthesia. Methods. Surgical patients undergoing general anesthesia with endotracheal intubation were recruited from a medical center. Patients were randomly assigned to group K (treated with 5% ketorolac tromethamine spray) or group D (treated with distilled water spray). Before intubation, each endotracheal tube was sprayed with the appropriate solution by physicians over the 20 cm length of the cuff. Each group comprised 95 patients fitting the inclusion and exclusion criteria for whom complete data sets were collected. The intensity of the sore throat was measured at 1, 3, 6, and 24 h after surgery, and data were compared. Results. The two groups had similar characteristics. Postoperative sore throat was significantly less frequent in group K than in group D (p < 0.001) and the pain intensity was significantly lower in group K than in group D at each time point (all p < 0.001). Conclusions. This study demonstrated that preanesthesia 5% ketorolac tromethamine spray could effectively decrease postendotracheal-intubation-induced sore throat in patients undergoing general anesthesia.

Mechanism of cholera toxin activation by a guanine nucleotide-dependent 19 kDa protein.

Cholera toxin causes the devastating diarrheal syndrome characteristic of cholera by catalyzing the ADP-ribosylation of Gs alpha, a GTP-binding regulatory protein, resulting in activation of adenylyl cyclase. ADP-ribosylation of Gs alpha is enhanced by 19 kDa guanine nucleotide-binding proteins known as ADP-ribosylation factors or ARFs. We investigated the effects of agents known to alter toxin-catalyzed activation of adenylyl cyclase on the stimulation of toxin- and toxin subunit-catalyzed ADP-ribosylation of Gs alpha and other substrates by an ADP-ribosylation factor purified from a soluble fraction of bovine brain (sARF II). In the presence of GTP, sARF II enhanced activity of both the toxin catalytic unit and a reduced and alkylated fragment ('A1'), as a result of an increase in substrate affinity with no significant effects on Vmax. Activation of toxin was independent of Gs alpha and was stimulated 4-fold by sodium dodecyl sulfate, but abolished by Triton X-100. sARF II therefore serves as a direct allosteric activator of the A1 protein and may thus amplify the pathological effects of cholera toxin.

Genomic organization and the promoter region of the round-spotted pufferfish (Tetraodon fluviatilis) CDC37 gene.

The CDC37 gene was isolated from a round-spotted pufferfish genomic library and characterized. This gene is composed of nine exons spanning 3.5 kb. Exon 1 contains the 5'-untranslated region and exon 2 contains the putative translation initiation site. By 5'-RACE (rapid amplication of cDNA ends) and sequence analysis, we deduced the promoter region for the CDC37 gene and found that it does not contain typical TATA or CCAAT box. The 1.8 kb DNA fragment upstream of the putative transcription initiation site contains numerous potential binding sites for transcription factors including CREB, E2A, Ets-1, GATA, NF-IL6 and PEA3. When this DNA fragment was placed upstream of the chloramphenicol acetyltransferase (CAT) reporter gene and transfected into a carp CF cell line, it could drive the synthesis of CAT enzyme four times more efficiently than the promoterless pCAT-Basic did. In addition, the CDC37 gene is linked to the TYK2 gene in a tail-to-head manner with a small intergenic region of 292 bp.

Gene rearrangements of T cell receptor beta and gamma chains in HTLV-I infected primary neoplastic T cells.

Rearrangements of T cell receptor beta and gamma chain (T beta and T gamma) genes were analyzed by Southern blot method in samples from 30 patients with adult T cell leukemia (ATL) and 17 patients with non-ATL T cell neoplasms. The DNA probes used were the constant and joining region of T beta gene and the joining region of T gamma gene. Rearranged bands of T beta gene on one or both allelic chromosomes were detected in all neoplastic T cells, even those of smoldering ATL, in which only a small percentage of peripheral blood T cells were detected as leukemic. T gamma gene was rearranged in the cells of all but one patient, the exception being one ATL patient. In order to test whether any given variable region (V) of T beta gene was expressed in ATL cells, two functionally rearranged V beta sequences of ATL were compared with a V beta sequence from T cells acute lymphoblastic leukemia cells. No significant homologies were noted among the three deduced gene product amino acid sequences, confirming that T beta molecules of ATL cells contained no specific structures in common. The observed heterogeneity of T beta and T gamma gene rearrangements in ATL cells further supported these findings.

Quickly predicting chemotherapy response to paclitaxel-based therapy in non-small cell lung cancer by early technetium-99m methoxyisobutylisonitrile chest single-photon-emission computed tomography.

The purpose of this study was to retrospectively predict the chemotherapy response to paclitaxel in non-small cell lung cancer (NSCLC) using technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) chest single-photon-emission computed tomography (SPECT) to detect the expression of multidrug-resistance-mediated Mr 170,000 P-glycoprotein. Before chemotherapy with Paclitaxel (Taxol), 30 patients with stage IIIb or IV NSCLC were enrolled in this study. Early chest SPECT 10 min after i.v. injection of Tc-99m MIBI was performed to qualitatively interpret Tc-99m MIBI chest SPECT visually and quantitatively calculate early tumor:normal lung ratios (T:NL) for quick assessment of multidrug-resistant P-glycoprotein expression in NSCLC. On the basis of qualitatively visual interpretation of early Tc-99m MIBI chest SPECT, all of 15 (100%) cases with good response to chemotherapy with Taxol could be detected but 10 (67%) of 15 cases with poor response could not be detected. Early Tc-99m MIBI chest SPECT could correctly predict chemotherapy response in 25 (83%) of 30 of cases. The early T:NL were 3.30 +/- 0.82 for 15 patients with good response and 2.02 +/- 0.19 for 5 patients with poor response. The differences were significant (P < 0.05) by independent Student t tests. However, no significant differences were found for other prognostic factors (age, sex, tumor size, tumor location, stage, and cell type) between good-response and poor-response patients. Early Tc-99m MIBI chest SPECT has the potential to predict chemotherapy response to Paclitaxel.

Stimulation of diploid fibroblast growth with serum-free medium conditioned by mezerein-treated monocytic leukemia cells.

Medium conditioned by mezerein-treated human acute monocytic leukemia cells (THP-1) stimulated human fibroblast replication. Maximum mitogenic activity was elaborated by THP-1 cells with a 24-hr incubation in 10(-7) M mezerein (activator phase) followed by a 36-hr incubation in insulin-supplemented serum-free Roswell Park Memorial Institute (RPMI)-1640 medium (effector phase). Growth stimulation was not due to the presence of residual mezerein. We previously reported that leukemia cells also produced a growth inhibitor. Fibroblast stimulation was resolved by isoelectrofocusing into several active fractions separate from the growth inhibitory activity for malignant mammary cells. Conditioned medium was mitogenic for fibroblasts in the presence of high concentrations of fetal bovine and human whole blood sera. Growth stimulation was observed in plasma-derived serum only when supplemented with exogenous platelet-derived growth factor. Thus, this THP-1 cell product does not fulfill the role of a competence factor.