Michael Bromberg

Formation of tissue factor-factor VIIa-factor Xa complex induces activation of the mTOR pathway which regulates migration of human breast cancer cells

Tissue factor (TF) is a transmembrane glycoprotein that initiates blood coagulation when complexed with activated factor VII (FVIIa). TF is constitutively expressed in a variety of tumor cells and has been implicated in cellular signaling, angiogenesis, and tumor progression. Formation of TF-FVIIa complex and generation of downstream coagulation proteases, including activated factor X (FXa) and thrombin, initiate signaling by activation of protease-activated receptors (PARs). We have previously shown that TF-FVIIa-Xa complex formation promotes phosphorylation of p44/42 mitogen-activated protein kinase and Akt/protein kinase B in human breast cancer cells. In the present study, we show that formation of TF-FVIIa-FXa complex induces phosphorylation of mammalian target of rapamycin (mTOR) and p70 S6 kinase in a human breast cancer cell line, Adr-MCF-7. Activation of the mTOR pathway, which is probably mediated by PAR1 and/or PAR2, was associated with enhanced cell migration, a key step in the metastatic cascade. Inhibition of this pathway with the specific mTOR inhibitor, rapamycin, markedly decreased cell migration induced by formation of TF-FVIIa-FXa complex. These studies suggest that TF-FVIIa-mediated signaling modulates mTOR pathway activation, which regulates in part breast cancer cell migration. Targeting the TF-mediated cell signaling pathway might represent a novel strategy for the treatment of breast cancer.

Cleaved high-molecular-weight kininogen and its domain 5 inhibit migration and invasion of human prostate cancer cells through the epidermal growth factor receptor pathway

Upregulation and activation of epidermal growth factor receptor and/or urokinase-type plasminogen activator receptor in a variety of cancers have been shown to be associated with poor prognosis. High-molecular-weight kininogen can be hydrolysed by plasma kallikrein to bradykinin and cleaved high-molecular-weight kininogen (HKa). HKa and its domain 5 (D5) both have been shown to have potent anti-angiogenic activity. We now show that HKa blocks human prostate cancer cell (DU145) migration by 76.0±2.4% at 300 nM and invasion by 78.0±12.9% at 11.1 nM. D5 inhibits tumor migration and invasion in a concentration-dependent manner. Stimulation by basic fibroblast growth factor (bFGF) or vascular endothelial growth factor results in clustering of urokinase-type plasminogen activator receptor (uPAR) and epidermal growth factor receptor (EGFR) on the surface of DU145 cells. The co-localization of uPAR and EGFR is prevented by HKa. Immunoprecipitation suggests that uPAR, EGFR and α5β1 integrin formed a ternary complex. Immunoblotting shows that HKa significantly decreases the bFGF-transactivated phosphorylation of EGFR at Tyr 1173 between 30 min and 4 h. The phosphorylation of extracellular signal-regulated kinase (ERK) and AKT, which are downstream effectors of EGFR, is also inhibited by HKa. These novel data indicate that HKa and D5 inhibit migration and invasion of human prostate cancer cells through an EGFR/uPAR pathway, suggesting the therapeutic potential of HKa and D5 to decrease metastasis of human prostate cancer.

Tissue Factor as a Novel Target for Treatment of Breast Cancer

Tissue factor (TF), a 47-kDa transmembrane glycoprotein that initiates blood coagulation when complexed with factor VIIa (FVIIa), is expressed in several tumor types. TF has been shown to play a role in cell signaling, inflammation, angiogenesis, as well as tumor growth and metastasis. Activation of the TF signaling pathway has been implicated in mediating the function of many tumor cell types and has led to TF as a potential target in the treatment of several malignancies. Formation of the TF-FVIIa complex in breast cancer cells has been shown to exert an antiapoptotic effect and play a key role in tumor growth and metastasis. Breast cancer growth is suppressed by inhibition of TF-mediated PAR2 signaling, and deficiency in PAR2 delays spontaneous breast cancer development in mice. TF is expressed in triple-negative breast cancer (TNBC), an aggressive type of breast cancer in which there is currently a paucity of available targets. Various methods of targeting TF have been investigated and include immunoconjugates or icons, anti-TF antibodies, TF pathway inhibitors, targeted photodynamic therapy, and microRNAs. These investigations may give way to promising clinical therapies for breast cancer, especially in TNBC, for which there are relatively few effective treatment options.

Plasmacytic post‐transplant lymphoproliferative disorder: a case series of nine patients

Post‐transplant lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation. Although PTLD typically has a B‐cell histology, an uncommon variant, plasmacytic PTLD can present as a monoclonal plasma cell proliferation similar to plasmacytomas seen in multiple myeloma. A retrospective analysis was performed on nine patients at our center with plasmacytic PTLD as characterized by plasmacytic histology with the presence of CD138 and lack of CD20. Of the 210 adult solid organ transplant PTLD patients diagnosed between 1988 and 2012, 9 (4%) had a histological appearance consistent with plasmacytic PTLD. The median time from transplant to diagnosis was 3.7 years (range 8 months–24 years). All patients presented with extranodal and often subcutaneous solid tumors. Laboratory features included elevated LDH and beta‐2 microglobulin levels, monoclonal gammopathy, and EBV positivity of the tumor. Unlike conventional multiple myeloma, patients had normal calcium levels and only mild anemia. Six patients who have completed treatment achieved complete responses with radiation therapy and/or reduction in immunosuppression with two patients now greater than 5 years in continuous complete response. Plasmacytic PTLD, despite its plasmacytic histology, is responsive to conventional therapies used for B‐cell PTLD including reduction in immunosuppression and radiation therapy.

Upregulation of tissue factor in monocytes by cleaved high molecular weight kininogen is dependent on TNF-α and IL-1β

Inflammatory bowel disease and arthritis are associated with contact activation that results in cleavage of kininogen to form high molecular weight kininogen (HKa) and bradykinin. We have previously demonstrated that HKa can stimulate inflammatory cytokine and chemokine secretion from human monocytes. We now show that HKa can upregulate tissue factor antigen and procoagulant activity on human monocytes as a function of time (1-4 h) and HKa concentration (75-900 nM). The amino acid sequence responsible to block HKa effects is G440-H455. The HKa receptor macrophage-1 (Mac-1; CD11b18) is the binding site as shown by inhibition by a monoclonal antibody to CD11b/18. Chemical inhibitors of JNK, ERK, and p38 signaling pathways block cell signaling, as does an inhibitor to the transcription factor NF-kappaB. A combination of monoclonal antibodies to TNF-alpha and IL-1beta but neither alone inhibited the HKa induction of tissue factor. These results suggest that HKa mimics LPS by triggering a paracrine pathway in monocytes that depends on TNF-alpha and IL-1beta. Antibodies to kininogen or peptidomimetics might be a useful and safe therapy in inflammatory diseases or sepsis involving cytokines.

Hypercoagulability in End-Stage Liver Disease: Prevalence and Its Correlation With Severity of Liver Disease and Portal Vein Thrombosis

Contrary to well-recognized bleeding diathesis in chronic liver disease, thrombotic events can occur in these patients due to reduction or loss of synthesis of anticoagulant proteins. Forty-seven consecutive patients with end-stage liver disease (ESLD) were investigated for activity of protein C, protein S, antithrombin, and factor V Leiden mutation. Forty-two (89.4%) patients had low levels of at least 1 while 33 (70.2%) patients were deficient for all anticoagulant proteins studied. Forty-six (97.9%) patients were negative for factor V Leiden mutation. The deficiencies were more marked in hepatitis C virus–positive patients and patients with model for end-stage liver disease (MELD) score >15. Six (12.8%) patients had portal vein thrombosis (PVT), and all had diminished protein S activity. In conclusions, deficiency of anticoagulant proteins occur in early phase of chronic liver disease. The severity of deficiency is proportional to the severity of liver disease. Despite the high prevalence of hypercoagulability, the incidence of PVT is low. Further studies with larger cohort of patients are needed to support these conclusions and to study other associated factors.

Lymphoid malignancy-associated hemophagocytic lymphohistiocytosis: Search for the hidden source

Secondary hemophagocytic lymphohistiocytosis (HLH) is an uncommon, but life-threatening syndrome of highly stimulated and ineffective immune dysregulation. It is not a disease entity by itself and the current diagnosis of secondary (acquired) HLH is based on constellation of nonspecific clinical and laboratory parameters indicative of overactive immune response. The presenting symptoms are often nonspecific and could potentially be missed, leading to a fatal outcome. Patients with malignancy-associated HLH have a relatively unfavorable overall survival compared with non-malignancy-associated HLH. In this retrospective study, nine adult patients with secondary HLH were identified. Of these four cases were associated with a malignancy and despite a high degree of suspicion, the underlying lymphoid malignancy was not initially evident. Three out of four patients with lymphoid malignancy-associated HLH died over a very short course of time following the diagnosis. The outcome was significantly different for the control group of patients with other underlying cause(s) for HLH. These cases emphasize the importance of a thorough search for a hidden malignant source in patients with secondary HLH for prompt diagnosis and institution of malignancy specific treatment.

Mucosa-Associated Lymphoid Tissue Lymphoma of the Sigmoid Colon Discovered on Routine Screening Colonoscopy in Patient with Hepatitis C and Helicobacter pylori Infection

Mucosa-associated lymphoid tissue (MALT) lymphoma is predominantly found in the stomach. Rarely, it is found in the proximal colon and even less so in the sigmoid colon. We present a rare case of primary sigmoid colon MALT lymphoma in a patient with concomitant Helicobacter pylori and hepatitis C infection. We also review current imaging, staging, and therapeutic modalities. To our knowledge, this is the first sigmoid colon MALT lymphoma reported in the United States.