Patient-derived xenograft (PDX) models have been shown to recapitulate many characteristics of human tumors and have been increasingly used for anticancer drug development, molecular characterization of cancer biology, and development of precision therapies. However, because PDXs are grown in immunodeficient mouse strains, they are regarded as inappropriate for preclinical evaluation of anticancer immunotherapy. Here we evaluated whether patient-derived immune cells co-exist in PDXs derived from lung cancer patients. First-generation PDX (F1) was established by subcutaneously implanting human tumor tissue into non-obese diabetic-severe combined immunodeficiency (NOD-SCID) mice with a null mutation of the gene encoding for interleukin-2 receptor g (NSG). When the resulting tumors in these mice grew to about 1.5 cm in diameter, we passaged the tumors in NSG or nude mice for subsequent generations. A small piece of these PDX tissues (about 2-3 mm3) were minced into fragments and cultured in media containing human interleukin-2 (IL-2) (2000 -6000 units/ml) for up to 6 weeks. The proliferated lymphocytes for analyzed by fluorescence-activated cell sorting (FACS) with antibodies specific for human immune cell surface markers. The provenance of cultured cells was determined by DNA fingerprinting assay together with patients’ DNA samples from primary tumors and/or peripheral blood mononuclear cells (PBMC). The mean time of PDX growth in NSG mice before harvesting for culturing tumor-infiltrating lymphocytes (TILs) was 120 days (ranging from 63-292 days). TILs were successfully cultured from 8 of 25 PDXs samples (about 32%), with one from F2 PDXs and 7 from F1 PDXs. TILs from five of those PDXs were predominantly human CD3+CD8+ T cells (72% -99%), while the remaining three were predominantly human CD19+ B cells (77% - 95%). DNA fingerprint analysis showed that genotypes of TILs were identical to patients’ primary tumors and/or PBMC, demonstrating that the TILs were from the same patients as the PDXs. Further analysis showed that CD8+ T cells from PDXs were CD45RO+, with either CD62L+ or CD62L-. Patient-derived immune cells co-exist with PDXs in some lung cancer PDX models. Most of those immune cells were CD3+CD8+ and could be memory T cells. These results suggest that some PDXs might be used for evaluating functions of tumor resident immune cells and/or for evaluating anticancer immunotherapies.

Background—Activating enhancer-binding protein-2β (AP2β) is a transcription factor involved in apoptosis. The purpose of the current study was to assess the cellular location and level of AP2β in Non-Small Cell Lung Cancer (NSCLC) and normal lung tissue and investigate whether the level and localization of AP2β expression is predictive of overall survival in patients with stage I NSCLC. Methods—We performed immunohistochemical analysis of tissue microarrays (TMAs) prepared from stage I NSCLC specimens with adjacent normal lung tissue from two independent sets of patients who underwent lung resection with curative intent at our institution. AP2β intensity was assessed in TMAs, and AP2β staining patterns were classified as either diffuseor nucleolar in the TMAs. AP2β intensity and localization were analyzed for correlation with patients' survival. Results—Immunohistochemical analysis of TMAs showed that the intensity of AP2β immunohistochemical staining did not correlate with overall survival. When location of AP2β was analyzed in TMAs, all of the normal lung tissue had diffuse pattern of AP2β. In the first set of NSCLC, patients with nucleolar pattern had a significantly lower 5-year survival rate than patients with diffuse pattern (67% vs. 100%; P = 0.004); this finding was confirmed in the second set (64% © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved Corresponding Author: Min P Kim, MD, Department of Surgery, The Methodist Hospital, 6550 Fannin Street, SM1661, Houston, TX 77030. Phone: 713-441-5177; Fax: 713-790-6472; mpkim@tmhs.org. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author Manuscript Ann Thorac Surg. Author manuscript; available in PMC 2012 September 1. Published in final edited form as: Ann Thorac Surg. 2011 September ; 92(3): 1044–1050. doi:10.1016/j.athoracsur.2011.04.029. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript vs. 91%; P = 0.02). Multivariate analysis revealed that nucleolar pattern was an independent predictor of poor overall survival in both sets. Conclusions—The AP2β which is located in the nucleoplasm in normal lung tissue is found in either nucleoplasm or nucleoli in NSCLC. The patients with AP2β in the nucleoli had poor survival compared to patients with AP2β in the cytoplasm.

BackgroundActivating enhancer-binding protein-2β (AP2β) is a transcription factor involved in apoptosis. The purpose of the current study was to assess the cellular location and level of AP2β in non-small cell lung cancer (NSCLC) and normal lung tissue and investigate whether the level and localization of AP2β expression is predictive of overall survival in patients with stage I NSCLC.MethodsWe performed immunohistochemical analysis of tissue microarrays (TMAs) prepared from stage I NSCLC specimens with adjacent normal lung tissue from two independent sets of patients who underwent lung resection with curative intent at our institution. The AP2β intensity was assessed in TMAs, and AP2β staining patterns were classified as either diffuse or nucleolar in the TMAs. The AP2β intensity and localization were analyzed for correlation with patients' survival.ResultsImmunohistochemical analysis of TMAs showed that the intensity of AP2β immunohistochemical staining did not correlate with overall survival. When location of AP2β was analyzed in TMAs, all of the normal lung tissue had diffuse pattern of AP2β. In the first set of NSCLC, patients with nucleolar pattern had a significantly lower 5-year survival rate than patients with diffuse pattern (67% versus 100%; p = 0.004); this finding was confirmed in the second set (64% versus 91%; p = 0.02). Multivariate analysis revealed that nucleolar pattern was an independent predictor of poor overall survival in both sets.ConclusionsThe AP2β, which is located in the nucleoplasm in normal lung tissue, is found in either nucleoplasm or nucleoli in NSCLC. The patients with AP2β in the nucleoli had poor survival compared with patients with AP2β in the cytoplasm.

The title lanthanide–bdc complex, {[Lu 2 (C 8 H 4 O 4 ) 3 (H 2 O) 8 ]·2H 2 O} n (bdc is benzene-1,4-dicarboxyl­ate), was synthesized under hydro­thermal conditions. In this complex, the Lu III centers are eight-coordinated by four O atoms from three benzene-1,4-dicarboxyl­ate ligands and four from water mol­ecules. Lu III ions are bridged by benzene-1,4-dicarboxyl­ate anions in two modes, forming polymeric chains. These chains are further assembled into a three-dimensional supramol­ecular network by O—H⋯O hydrogen-bonding inter­actions.

The title lanthanide–bdc complex, {[Lu2(C8H4O4)3(H2O)8]·2H2O}n (bdc is benzene-1,4-dicarboxyl­ate), was synthesized under hydro­thermal conditions. In this complex, the LuIII centers are eight-coordinated by four O atoms from three benzene-1,4-dicarboxyl­ate ligands and four from water mol­ecules. LuIII ions are bridged by benzene-1,4-dicarboxyl­ate anions in two modes, forming polymeric chains. These chains are further assembled into a three-dimensional supramol­ecular network by O—H⋯O hydrogen-bonding inter­actions.

A great deal of experimental evidence connects induction of polyamine catabolism via spermidine/spermine N1-acetyltransferase (SSAT) to antiproliferative activity and apoptosis. Following our initial observation from gene expression profiling that platinum drugs induce SSAT, we undertook this present study to characterize platinum drug induction of SSAT and other polyamine catabolic enzymes and to examine how these responses might be enhanced with the well-known inducer of SSAT and clinically relevant polyamine analogue, N1,N11-diethylnorspermine (DENSPM). The results obtained in A2780 ovarian cancer cells by real-time quantitative RT-PCR and Northern blot analysis show that a 2-hour exposure of A2780 cells to platinum drugs induces expression of SSAT, a second SSAT (SSAT-2), spermine oxidase, and polyamine oxidase in a dose-dependent manner. At equitoxic doses, oxaliplatin is more effective than cisplatin in SSAT induction. The most affected enzyme, SSAT, increased 15-fold in mRNA expression and 2-fold in enzyme activity. When combined with DENSPM to further induce SSAT and to enhance conversion of mRNA to activity, oxaliplatin increased SSAT mRNA 50-fold and activity, 210-fold. Polyamine pools declined in rough proportion to levels of SSAT induction. At pharmacologically relevant oxaliplatin exposure times (20 hours) and drug concentrations (5 to 15 micromol/L), these responses were increased even further. Combining low-dose DENSPM with oxaliplatin produced a greater than additive inhibition of cell growth based on the sulforhodamine-B assay. Taken together, the findings confirm potent induction of polyamine catabolic enzymes, such as SSAT by platinum drugs, and demonstrate that these biochemical responses as well as growth inhibition can be potentiated by co-treatment with the polyamine analogue DENSPM. With appropriate in vitro and in vivo optimization, these findings could lead to clinically relevant therapeutic strategies.

The clinically relevant polyamine analogue N(1),N(11)-diethylnorspermine (DENSPM) inhibits cell growth by down-regulating polyamine biosynthesis, up-regulating polyamine catabolism at the level of spermidine/spermine N(1)-acetyltransferase (SSAT), and depleting intracellular polyamine pools. Among human melanoma cell lines, the analogue causes rapid apoptosis in SK-MEL-28 cells and a sharp G(1) arrest in MALME-3M cells. This study reveals that DENSPM potently activates the mitogen-activated protein kinase (MAPK) pathways in melanoma cells and investigates the role of this response in determining cellular outcomes. Onset of apoptosis was preceded by an intense phosphorylation of the MAPKs, including extracellular signal-regulated kinase 1/2, c-Jun NH(2)-terminal kinase, and p38 in both SK-MEL-28 and MALME-3M cells. A panel of DENSPM analogues differing only in their ability to induce SSAT was used to show that MAPK activation was causally linked to induction of SSAT activity and related oxidative events. The latter was confirmed with the polyamine oxidase inhibitor MDL-75275 and the antioxidant N-acetyl-L-cysteine, which when used in combination with DENSPM, decreased MAPK activation and as previously shown, reduced apoptosis. The MAP/extracellular signal-regulated kinase-1 inhibitor PD 98059 reduced activation of all three kinases but failed to alter apoptosis in DENSPM-treated SK-MEL-28 cells. By contrast, the inhibitor prevented p21(waf1/cip1) induction and enhanced apoptosis in MALME-3M cells as indicated by accelerated caspase-3 activation and positive annexin V staining. The generality of this effect was demonstrated in DENSPM-treated A375 and LOX human melanoma cells. Taken together, the importance of the MAPK pathways in determining the biological response to DENSPM treatment is dependent on the genetic environment of the cell.

We have previously shown that the clinically relevant polyamine analog N1,N11-diethylnorspermine (DENSPM) causes rapid apoptosis in human melanoma SK-MEL-28 cells via a series of events that include mitochondrial release of cytochrome c and activation of the caspase cascade. Upstream to these events, DENSPM downregulates polyamine biosynthesis and potently upregulates polyamine catabolism at the level of spermidine/spermine N1-acetyltransferase (SSAT). In searching for downstream effectors that either contribute to or abrogate the apoptotic response, we observed that DENSPM treatment of SK-MEL-28 cells for 30 h led to cytosolic release of Smac/Diablo, a mitochondrial protein known to bind and inhibit the function of inhibitor of apoptosis proteins (IAPs). Subsequently, we found that DENSPM markedly lowered survivin and ML-IAP protein (but not XIAP) levels by 18 h via an apparently Smac/Diablo-independent pathway. Proteasome inhibitors fully prevented survivin and ML-IAP protein loss as well as apoptosis, suggesting that the proteasome-mediated degradation of survivin and ML-IAP is causally linked to the cellular outcome. We also observed that structural analogs of DENSPM which differentially induced SSAT and apoptosis lowered survivin and ML-IAP levels in a manner that correlated with enzyme activity. The linkage between IAPs and SSAT was more directly established by the finding that selective prevention of SSAT induction by small interfering RNA prevented survivin and ML-IAP loss as well as apoptosis during DENSPM treatment. Among the melanoma cell lines (SK-MEL-28, MALME-3M, A375 and LOX), survivin degradation correlated temporally with the onset of DENSPM induced apoptosis or growth inhibition. By contrast, ML-IAP degradation occurred only during rapid apoptosis seen in SK-MEL-28 cells. These data suggest a sequence of events whereby DENSPM induction of SSAT leads to loss of IAP proteins and a more fulminate apoptotic response. The findings implicate survivin and ML-IAP as important determinants of polyamine analog drug action in melanoma cells.

N1,N11-diethylnorspermine (DENSPM) is a polyamine analog that down-regulates polyamine biosynthesis and potently upregulates the polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SSAT). In certain cells, such as SKMEL-28 human melanoma cells, induction of SSAT is associated with rapid apoptosis. In this study, we used small interfering RNA (siRNA) to examine the role of SSAT induction in mediating polyamine pool depletion and apoptosis. siRNA duplexes were designed to target three independent sites in the SSAT mRNA coding region (siSSAT). When transfected under nontoxic conditions, two of the duplexes selectively reduced basal SSAT mRNA in HEK-293 cells by >80% and prevented DENSPM-induced SSAT mRNA by 95% in SK-MEL-28 cells. Treatment of SK-MEL-28 cells with 10 muM DENSPM in the presence of 83 nM siSSAT selectively prevented the 1400-fold induction of SSAT activity by approximately 90% and, in turn, prevented analog depletion of spermine (Spm) pools by approximately 35%. siSSAT also prevented DENSPM-induced cytochrome c release and caspase-3 cleavage at 36 h and apoptosis at 48 h as measured by annexin V staining. Overall, the data directly link analog induction of SSAT to Spm pool depletion and to caspase-dependent apoptosis in DENSPM-treated SK-MEL-28 cells. This represents the first use of siRNA technology directed toward a polyamine gene and the first unequivocal demonstration that SSAT induction initiates events leading to polyamine analog-induced apoptosis.

In the polyamine back-conversion pathway, spermine and spermidine are first acetylated by spermidine/spermine N(1) -acetyl-transferase (SSAT-1) and then oxidized by polyamine oxidase to produce spermidine and putrescine respectively. Herein we apply homology-search methods to identify novel sequences belonging to a second SSAT, SSAT-2, with a chromosomal location at 17p13.1, which is distinct from SSAT-1 at Xp22. Human SSAT-2 cDNA derived from small-cell lung carcinoma was deduced to encode a 170-amino-acid protein having 46% sequence identity and 64% sequence similarity with SSAT-1. When transiently transfected into HEK-293 cells, SSAT-1 decreased spermidine and spermine pools by approximately 30%, while, at the same time, significantly increasing putrescine, N (1)-acetylspermidine, N (1)-acetylspermine and N (1), N (12)-diacetylspermine pools. By contrast, transfected SSAT-2 had no effect on intracellular polyamine or acetylated polyamine pools. When enzyme activity was assayed on enzyme extracts from transfected cells, both SSAT-1 and SSAT-2 demonstrated much higher acetylating activity than vector-transfected cells. The data suggest that, in intact cells, SSAT-2 may be compartmentalized or it may be inefficient at low intracellular polyamine concentrations. By substituting candidate substrates in the enzyme assay, we determined that SSAT-1 shows the substrate preference norspermidine=spermidine>>spermine> N (1)-acetylspermine>putrescine, whereas SSAT-2 shows the preference norspermidine>spermidine=spermine>> N (1)-acetylspermine=putrescine. Analysis of mRNA levels in cell lines and ESTs (expressed sequence tags) from various tissues by digiNorthern (a web-based tool for virtually displaying expression profiles of query genes based on EST sequences) indicated that SSAT-1 tends to be more widely and highly expressed than SSAT-2. While SSAT-1 mRNA was inducible by polyamine analogues in a variety of cell lines, SSAT-2 was not. The existence of an active, but possibly sequestered, SSAT-2 enzyme suggests that, under certain conditions, it may be recruited into basal or perturbed polyamine metabolism.

The cell cycle regulatory events that interface with polyamine requirements for cell growth have not yet been clearly identified. Here we use specific inhibitors of polyamine biosynthetic enzymes to investigate the effect of polyamine pool depletion on cell cycle regulation. Treatment of MALME-3M cells with either the ornithine decarboxylase inhibitor alpha-difluoromethylornithine or the S-adenosylmethionine decarboxylase inhibitor MDL-73811 lowered specific polyamine pools and slowed cell growth but did not induce cell cycle arrest. By contrast, treatment with the combination of inhibitors halted cell growth and caused a distinct G1 arrest. The latter was associated with marked reduction of all three polyamine pools, a strong increase in p21(WAF1/CIP1/SDI1) (p21), and hypophosphorylation of retinoblastoma protein. All effects were fully prevented by exogenous polyamines. p21 induction preceded p53 stabilization in MALME-3M cells and also occurred in a polyamine-depleted, p53-nonfunctional melanoma cell line, indicating that p21 is induced at least in part through p53-independent mechanisms. Conditional overexpression of p21 in a fibrosarcoma cell line was shown previously to inhibit the expression of multiple proliferation-associated genes and to induce the expression of genes associated with various aspects of cell senescence and organism aging. Polyamine depletion in MALME-3M cells was associated with inhibition of seven of seven tested p21-inhibited genes and with induction of 13 of 14 tested p21-induced genes. p21 expression is also known to induce a senescence-like phenotype, and phenotypic features of senescence were observed in polyamine-depleted MALME-3M cells. Cells increased in size, appeared more granular, and expressed senescence-associated beta-galactosidase. Cells released from the polyamine inhibition lost the ability to form colonies, failed to replicate their DNA, and approximately 25% became bi- or multinucleated. These events parallel the outcome of prolonged p21 induction in fibrosarcoma cells. The results of this study indicate that polyamine pool depletion achieved by specific biosynthetic enzyme inhibitors causes p21-mediated G1 cell cycle arrest followed by p21-mediated changes in gene expression, development of a senescence-like phenotype, and loss of cellular proliferative capacity.

N(1),N(11)-Diethylnorspermine (DENSPM) is a polyamine analogue with clinicalrelevance as an experimental anticancer agent and the ability to elicit a profound apoptotic response in certain cell types. Here, we characterize the polyamine effects and apoptotic signaling events initiated by treatment of SK-MEL-28 human melanoma with 10 microM DENSPM. Maximal induction of the polyamine catabolic enzyme spermidine/spermine N(1)-acetyltransferase (SSAT) and polyamine pool depletion were seen by 16 h, whereas early apoptosis was first apparent at 36 h. Intermediate events related to apoptotic signaling were sought between 16 and 36 h. A loss of mitochondrial transmembrane potential (Deltapsi(m)) beginning at 24 h was followed by the release of cytochrome c into the cytosol at 30 h. Loss of mitochondrial integrity was accompanied by caspase-3 activation and poly(ADP-ribose) polymerase digestion from 30 to 36 h. The caspase inhibitor Z-Asp-2,6-dichlorobenzoyloxymethylketone rendered cells resistant to analogue-induced caspase-3 activation and reduced the apoptotic response in a dose-dependent manner. Because polyamine reduction achieved by inhibitors of polyamine biosynthesis inhibited growth but did not cause apoptosis, we looked for alternative polyamine-related events, focusing on induction of SSAT. Three DENSPM analogues that differentially induced SSAT activity but similarly depleted polyamine pools revealed a close correlation between enzyme induction and cytochrome c release, caspase activation, and apoptosis. Dose-dependent inhibition of polyamine oxidase, an enzyme that oxidizes acetylated polyamines generated by SSAT and releases toxic by-products such as H(2)O(2) and aldehydes, prevented cytochrome c release, caspase activation, and apoptosis. Taken together, the findings indicate that DENSPM-induced apoptosis is at least partially initiated via massive induction of SSAT and related oxidative events and subsequently mediated by the mitochondrial apoptotic signaling pathway as indicated by cytochrome c release and caspase activation.