Hemoglobin-based oxygen carrier mitigates transfusion-mediated pancreas cancer progression.

BACKGROUND: Perioperative blood transfusion in pancreatic cancer patients is linked to decreased survival; however, a causal mechanism has not been determined. Previously we have shown that the plasma fraction of stored packed red blood cells (pRBCs) promotes pancreas cancer progression and associated morbidity. We hypothesize these untoward effects will be mitigated by use of a hemoglobin-based oxygen carrier (HBOC). METHODS: Cytokines and growth factors were measured in the plasma fraction from stored pRBCs and in an HBOC via cytokine array followed by formal enzyme-linked immunosorbent assay (ELISA). In an immunocompetent murine model, pancreas cancer progression was determined in vivo by bioluminescence, tumor weight, and number of metastases. RESULTS: Elevated levels of epidermal growth factor (EGF), platelet-derived growth factor BB (PDGF-BB), and regulated upon activation, normal T cell expressed and secreted (RANTES) were present in the plasma fraction of stored pRBCs, but were not found in the HBOC. Intravenous delivery of plasma fraction to mice with pancreatic cancer resulted in increased bioluminescence activity compared with mice that received HBOC. Metastatic events and pancreatic primary tumor weights were significantly higher in animals receiving plasma fraction from stored pRBCs compared with animals receiving HBOC. CONCLUSIONS: Intravenous receipt of the acellular plasma fraction of stored pRBCs promotes pancreatic cancer progression in an immunocompetent mouse model. These untoward events are mitigated by use of an HBOC.

Activation state of stromal inflammatory cells in murine metastatic pancreatic adenocarcinoma.

The histologic presence of macrophages (tumor-associated macrophages, TAMs) and neutrophils (tumor-associated neutrophils, TANs) has been linked to poor clinical outcomes for solid tumors. The exact mechanism for this association with worsened prognosis is unclear. It has been theorized that TAMs are immunomodulated to an alternatively activated state and promote tumor progression. Similarly, TANs have been shown to promote angiogenesis and tumor detachment. TAMs and TANs were characterized for activation state and production of prometastatic mediators in an immunocompetent murine model of pancreatic adenocarcinoma. Specimens from liver metastases were evaluated by immunofluorescence and immunoblotting. TAMS have upregulated expression of CD206 and CD163 markers of alternative activation, (4.14 ± 0.55-fold and 7.36 ± 1.13-fold over control, respectively, P < 0.001) but do not have increased expression of classically activated macrophage markers CCR2 and CCR5. TAMs also express oncostatin M (OSM). We found that TANs, not TAMs, predominantly produce matrix metalloproteinase-9 (MMP-9) in this metastatic tumor microenvironment, while MMP-2 production is pan-tumoral. Moreover, increased expression of VEGF colocalized with TAMs as opposed to TANs. TAMs and TANs may act as distinct effector cells, with TAMs phenotypically exhibiting alternative activation and releasing OSM and VEGF. TANs are localized at the invasive front of the metastasis, where they colocalize with MMP-9. Improved understanding of these interactions may lead to targeted therapies for pancreas adenocarcinoma.

Accumulation of pro-cancer cytokines in the plasma fraction of stored packed red cells.

INTRODUCTION: Perioperative blood transfusion has been linked to decreased survival in pancreatic cancer; however, the exact causal mechanism has not been elucidated. Allogeneic transfusions are known to expose patients to foreign cells and lipid mediators. We hypothesize that stored packed red cells (pRBCs) contain pro-cancer cytokines that augment tumor progression. We analyzed the plasma fraction of stored pRBCs for pro-cancer cytokines and evaluated the affect of both storage time and leukocyte reduction on these mediators. METHODS: Chemiarray™ analysis for pro-cancer cytokines was performed on the acellular plasma fraction of stored leukocyte-reduced (LR) and non-leukocyte-reduced (NLR) pRBCs at day 1 (D.1-fresh) and day 42 (D.42-outdate) of storage. Elevated expression of monocyte chemotactic protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), angiogenin, tumor necrosis factor-alpha (TNF-α), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) was found. Specific enzyme-linked immunosorbent assay was performed for each of these factors in LR and NLR blood at D.1, day 28, and D.42. Data were analyzed by ANOVA. A p value ≤ 0.05 was considered significant; N ≥ 4 per group. Migration assays were performed using inhibitors of EGF (gefitinib) and PDGF (imatinib) on murine pancreatic adenocarcinoma cells (Pan02) exposed to D.1 and D.42 LR and NLR plasma. Proliferation assays were performed on Pan02 cells to test the inhibition of PDGF. RESULTS: MCP-1 levels increased with storage time in LR blood, 86.3 ± 6.3 pg/ml at D.1 vs. 121.2 ± 6.1 pg/ml at D.42 (p = 0.007), and NLR blood, 78.2 ± 7.3 pg/ml at D.1 vs. 647.8 ± 220.7 pg/ml at D.42 (p = 0.02). RANTES levels are lower in LR compared to NLR stored blood, 3.0 ± 1.9 vs. 15.8 ± 0.7 pg/ml at D.42 (p < 0.001), but similar in D.1 blood, 13.8 ± 1.8 pg/ml in LR vs. 12.0 ± 1.6 pg/ml in NLR. Angiogenin levels were different between LR and NLR blood, 0 pg/ml (undetectable) vs. 44.2 ± 3.7 pg/ml (p < 0.001). Storage time did not affect concentration. TNF-α levels were not different between LR and NLR blood, and there was no storage time effect on concentration. EGF and PDGF levels increased with storage time in NLR blood only, 216.4 ± 3.8 pg/ml at D.1 vs. 1,436.4 ± 238.6 pg/ml at D.42 for EGF (p = 0.001), and 61.6 ± 6.0 pg/ml at D.1 vs. 76.5 ± 1.7 pg/ml at D.42 (p = 0.003) for PDGF. Inhibition of EGF reduced migration in Pan02 cells treated with D.42 NLR blood, 245.9 ± 11.2 vs. 164.6 ± 10.6 cells/hpf (p < 0.001). Inhibition of PDGF had no effect on Pan02 migration and reduced cell proliferation in cells treated with D.42 NLR, 181.1 ± 1.5% over control vs. 157.5 ± 2.1% (p < 0.001). CONCLUSION: Pro-cancer cytokines that can augment tumor progression were identified in pRBCs. Some of these factors are present in fresh blood. The soluble factors identified herein may represent possible therapeutic targets to offset negative effects of transfusion. These data stress the need for efforts in cancer patients to reduce transfusion requirements if needed.

Perioperative blood transfusions promote pancreas cancer progression.

Complex abdominal procedures to extirpate malignancies are often associated with blood transfusion. In particular, perioperative transfusion rates for pancreaticoduodenectomy can be as high as 75%. In the early 1970s it was shown that blood transfusions likely had immunomodulating effects as renal allografts were found to have longer survival in patients who received multiple transfusions. Subsequently, it has been suggested that blood transfusions may promote cancer progression. Many retrospective series have supported this hypothesis, and recent studies examining long-term survival in patients undergoing "Whipple" procedures suggests that transfusion is a negative prognostic factor. Despite these studies, the claim that transfusion is a simple surrogate for patient health, tumor size, location, and biology are difficult to refute. The use of syngeneic murine models has allowed many confounding variables to be controlled, and suggest that transfusion does indeed promote pancreas cancer progression. Based on these findings, as well as the continued need for blood transfusion, alternate strategies in transfusion management are warranted.

The plasma fraction of stored erythrocytes augments pancreatic cancer metastasis in male versus female mice.

BACKGROUND: Males with pancreatic cancer have decreased survival compared with females. Interestingly, perioperative blood transfusions have been shown to reduce survival in patients with pancreatic adenocarcinoma. Recent evidence incriminates blood transfusions from female donors as a causative factor in acute lung injury. We therefore hypothesize that male mice with pancreatic cancer will have greater tumor progression than female mice in response to transfusion. METHODS: Mice previously inoculated with pancreatic cancer cells received an intravenous injection of acellular plasma collected from single donor erythrocytes from either male or female donors. Control mice received an equal volume of intravenous saline. Necropsy to determine metastasis was performed in female mice at 4 wk status post-transfusion. The male group necessitated sacrifice at 3 wk post-transfusion due to clinical deterioration. RESULTS: Male mice developed more metastatic events than female mice, and this was accentuated when receiving blood from female donors. Male mice experienced weight loss within 2 wk of tail vein injection, and three mice in the male transfused groups died secondary to malignancy. Female mice did not manifest substantial weight loss, and did not die in the study time period. CONCLUSION: Male mice, compared with female, had significantly more metastatic events following transfusion of plasma from stored erythrocytes in an immunocompetent murine model of pancreatic adenocarcinoma. Moreover, the adverse effect of transfusion was augmented with female donor blood. These data are consistent with clinical outcomes from centers of excellence in treating pancreatic cancer and warrant further investigation.

Gender-specific transfusion affects tumor-associated neutrophil: macrophage ratios in murine pancreatic adenocarcinoma.

INTRODUCTION: Perioperative blood transfusion has been linked to decreased survival for pancreas cancer. Noting clinical data associating female blood products with increased morbidity, our lab has demonstrated that transfusion of female blood augments metastatic events compared to male blood in an immunocompetent murine pancreatic cancer model. It has been suggested that tumor-associated macrophages correlate with tumor progression by promoting angiogenesis. More recently, tumor-associated neutrophils have been implicated in aggressive tumor behavior. We hypothesize that differences in gender-specific transfusion-mediated pancreatic cancer progression are due to microenvironmental changes within the tumor. To test this hypothesis, we examined tumor-associated neutrophils and macrophage ratios in male and female mice with pancreatic cancer receiving blood transfusion from male or female donors. METHODS: C57/BL6 mice, age 7-9 weeks, underwent splenic inoculation with 2.5 × 10(5) PanO2 murine pancreatic adenocarcinoma cells. Mice were transfused on post-op day 7 with 1 ml/kg supernatant from day 42 male or female packed red cells. Necropsy was performed at 5 weeks or earlier for clinical deterioration, and tumors harvested. Frozen sections (5 µm) were stained for neutrophils and macrophages by immunofluorescence. Data were analyzed using ANOVA; p ≤ 0.05 was used to determine significance; N ≥ 3 per group. RESULTS: Clinically, male mice had greater morbidity and mortality than female mice when receiving female blood products, with roughened hair coat, development of ascites and death due to bowel obstruction. In evaluating the tumor microenvironment from mice receiving female blood products, male mice were noted to have a greater neutrophil to macrophage ratio than female mice, 0.176 ± 0.028 vs. 0.073 ± 0.012, p = 0.03. When examining neutrophil to macrophage ratio in mice receiving male blood products, no difference was noted (p = 0.48). CONCLUSIONS: Male mice with pancreas cancer have greater morbidity than female mice when receiving female blood products. Furthermore, the difference in neutrophil to macrophage ratio suggests that gender-specific blood transfusion promotes aggressive tumor behavior in male mice via microenvironmental changes. These data warrant further study to delineate sex-related differences in pancreatic cancer progression.

High-resolution quantitative imaging of mammalian and bacterial cells using stable isotope mass spectrometry.

BACKGROUND: Secondary-ion mass spectrometry (SIMS) is an important tool for investigating isotopic composition in the chemical and materials sciences, but its use in biology has been limited by technical considerations. Multi-isotope imaging mass spectrometry (MIMS), which combines a new generation of SIMS instrument with sophisticated ion optics, labeling with stable isotopes, and quantitative image-analysis software, was developed to study biological materials. RESULTS: The new instrument allows the production of mass images of high lateral resolution (down to 33 nm), as well as the counting or imaging of several isotopes simultaneously. As MIMS can distinguish between ions of very similar mass, such as 12C15N- and 13C14N-, it enables the precise and reproducible measurement of isotope ratios, and thus of the levels of enrichment in specific isotopic labels, within volumes of less than a cubic micrometer. The sensitivity of MIMS is at least 1,000 times that of 14C autoradiography. The depth resolution can be smaller than 1 nm because only a few atomic layers are needed to create an atomic mass image. We illustrate the use of MIMS to image unlabeled mammalian cultured cells and tissue sections; to analyze fatty-acid transport in adipocyte lipid droplets using 13C-oleic acid; to examine nitrogen fixation in bacteria using 15N gaseous nitrogen; to measure levels of protein renewal in the cochlea and in post-ischemic kidney cells using 15N-leucine; to study DNA and RNA co-distribution and uridine incorporation in the nucleolus using 15N-uridine and 81Br of bromodeoxyuridine or 14C-thymidine; to reveal domains in cultured endothelial cells using the native isotopes 12C, 16O, 14N and 31P; and to track a few 15N-labeled donor spleen cells in the lymph nodes of the host mouse. CONCLUSION: MIMS makes it possible for the first time to both image and quantify molecules labeled with stable or radioactive isotopes within subcellular compartments.

Androgens repress Bcl-2 expression via activation of the retinoblastoma (RB) protein in prostate cancer cells.

The oncogene Bcl-2 is upregulated frequently in prostate tumors following androgen ablation therapy, and Bcl-2 overexpression may contribute to the androgen-refractory relapse of the disease. However, the molecular mechanism underlying androgenic regulation of Bcl-2 in prostate cancer cells is understood poorly. In this study, we demonstrated that no androgen response element (ARE) was identified in the androgen-regulated region of the P1 promoter of Bcl-2 gene, whereas, we provided evidence that the androgenic effect is mediated by E2F1 protein through a putative E2F-binding site in the promoter. We further demonstrated that retinoblastoma (RB) protein plays a critical role in androgen regulation of Bcl-2. The phosphorylation levels of RB at serine residues 780 and 795 were decreased in LNCaP cells treated with androgens. Ectopic expression of a constitutively active form of RB inhibited expression of Bcl-2. Knockdown of endogenous RB protein by an Rb small inference RNA (siRNA) induced an increase in Bcl-2 levels. Most importantly, the effect of androgens on Bcl-2 was abolished completely by specific inhibition of RB function with a mutated E1A. Finally, androgen treatment of LNCaP cells upregulated specifically levels of the cyclin-dependent kinase inhibitors (CDKIs) p15INK4B and p27KIP1. Ectopic expression of p15INK4B and/or p27KIP1 inhibited Bcl-2 expression. Knockdown of endogenous p15INK4B or p27KIP1 protein with a pool of siRNAs diminished androgen-induced downregulation of Bcl-2 expression. Therefore, our data indicate that androgens suppress Bcl-2 expression through negatively modulating activities of the E2F site in the Bcl-2 promoter by activating the CDKI-RB axis.