Inhibition of protein disulfide isomerase with PACMA-31 regulates monocyte tissue factor through transcriptional and posttranscriptional mechanisms.

INTRODUCTION: Protein disulfide isomerase (PDI) contributes to tissue factor (TF) regulation in monocytes. While bacitracin and quercetin-3-rutinoside mitigate myeloid TF production, the effect of PACMA-31, a more specific PDI inhibitor with distinct pharmacologic properties, remains unclear. MATERIALS AND METHODS: Lipopolysaccharide (LPS) stimulation of peripheral blood mononuclear cells (PBMCs) or citrate-anticoagulated whole blood was carried out in the presence of PACMA-31 or DMSO vehicle before monocytes were analyzed for TF expression, including antigen, procoagulant activity (PCA) and mRNA, release of IL-6 and TNFα, and LPS-induced signaling pathways. RESULTS: While PACMA-31 alone had no effect, coincubation with LPS and PACMA-31 (25 µM) enhanced LPS-induced monocyte TF production in whole blood. The effect was at least partially regulated on the transcriptional level and could not be explained by increased phosphatidylserine membrane exposure. In contrast, the same PACMA-31 concentrations were cytotoxic in isolated PBMCs. A lower dose of PACMA-31, however, restored the stimulating effect by enhancing IκB-NFκB signaling that also increased the release of IL-6 and TNFα. The protease-activated receptor 2 (PAR2) inhibitor ENMD547 but not TF antibody 10H10 or factor Xa inhibitor rivaroxaban prevented the stimulatory effect of PACMA-31 on inflammatory monocytes. In sharp contrast, short time incubation of LPS-stimulated PBMCs with 25 µM PACMA-31 was non-cytotoxic and significantly inhibited cellular TF PCA but not surface antigen expression. CONCLUSIONS: PACMA-31 regulates monocyte TF in a concentration-dependent manner by opposing transcriptional and posttranscriptional mechanisms. While low concentrations of PACMA-31 augment monocyte TF production by amplifying LPS-dependent PAR2 signaling, high concentrations convert monocyte TF into its non-coagulant state.

Management of Vascular Thrombosis in Patients with Thrombocytopenia.

Platelets play critical roles in hemostasis and thrombosis. While low platelet counts increase the risk of bleeding, antithrombotic drugs, including anticoagulants and antiplatelet agents, are used to treat thromboembolic events. Thus, the management of thrombosis in patients with low platelet counts is challenging with hardly any evidence available to guide treatment. Recognition of the underlying cause of thrombocytopenia is essential for assessing the bleeding risk and tailoring therapeutic options. A typical clinical scenario is the occurrence of venous thromboembolism (VTE) in cancer patients experiencing transient thrombocytopenia during myelosuppressive chemotherapy. In such patients, the severity of thrombocytopenia, thrombus burden, clinical symptoms, and the timing of VTE relative to thrombocytopenia must be considered. In clinical practice, distinct hematological disorders characterized by low platelet counts and a thrombogenic state require specific diagnostics and treatment. These include the antiphospholipid syndrome, heparin-induced thrombocytopenia (HIT) and (spontaneous) HIT syndromes, disseminated intravascular coagulation, and paroxysmal nocturnal hemoglobinuria.

Prevalence of definite antiphospholipid syndrome in carriers of the JAK2V617F mutation.

INTRODUCTION: Patients with Philadelphia-negative myeloproliferative neoplasms (MPNs), particularly those carrying the JAK2V617F mutation, are at increased risk of thrombosis. While an association of MPNs with autoimmune disorders has been established, the prevalence of inherited or acquired thrombophilias in JAK2V617F-positive patients remains obscure. We therefore investigated the coincidence of the JAK2V617F mutation with additional thrombogenic risk factors. METHODS: In a retrospective study, we analyzed all patients referred for thrombophilia work-up between 01/2011 and 08/2019, in whom additional JAK2V617F mutation analysis was performed because of thromboembolic events that were recurrent, atypically located and/or associated with abnormal blood counts. RESULTS: Of 472 tested patients, 49 (10.4%) were JAK2V617F-positive. While the frequency of inherited thrombophilias (factor V Leiden and prothrombin G20210A mutation, deficiency of antithrombin, protein C, protein S) was not different between the two groups, the prevalence of definite antiphospholipid syndrome (APS), mostly associated with a moderate- or high-risk antibody profile, was significantly higher in patients with (22.4%) than in those without (8.4%) JAK2V617F mutation (p < 0.01). All evaluable JAK2V617F-positive patients with APS were subsequently diagnosed with MPN. In patients with JAK2V617F mutation, presence of concomitant APS was associated with a significantly younger age (49 ± 14 vs. 60 ± 15 years) at the time of thrombophilia work-up (p < 0.05). CONCLUSION: We found a significant association between JAK2V617F-positive MPN and definite APS. The presence of concomitant APS in patients carrying the JAK2V617F mutation may lead to earlier manifestation of thromboembolic events and may warrant more aggressive antithrombotic treatment strategies to prevent recurrence.

Effect of myeloperoxidase on the anticoagulant activity of low molecular weight heparin and rivaroxaban in an in vitro tumor model.

BACKGROUND: Inflammation with leukocyte activation is a hallmark of cancer-associated thrombosis (CAT), and elevated leukocytes predict venous thromboembolism in cancer outpatients. In a recent trial, rivaroxaban was more efficacious than dalteparin in preventing CAT recurrence. OBJECTIVES: In a proof-of-concept study, we aimed to provide a mechanistic basis for improved efficacy of rivaroxaban compared to low molecular weight heparin in CAT treatment. METHODS: We studied the effects of rivaroxaban, dalteparin, and tinzaparin at peak and trough levels on tumor cell-induced procoagulant activity and platelet aggregation in the presence or absence of the cationic leukocyte-derived enzyme, myeloperoxidase (MPO). Furthermore, pro-inflammatory conditions were generated by stimulating whole blood with lipopolysaccharide (LPS) or phorbol-myristate-acetate (PMA), before measuring thrombin generation in plasma supernatants. RESULTS: All three anticoagulants inhibited thrombin generation, fibrin clot formation, and platelet aggregation induced by the tissue factor-expressing prostate carcinoma cell line, 22Rv1. Pre-incubation with MPO partially attenuated the anticoagulant activity of dalteparin and tinzaparin, but not rivaroxaban, at trough levels. The effect of MPO did not involve the enzyme's catalytic properties, but required its structural integrity, as indicated by heat denaturation. In plasma obtained from LPS- or PMA-stimulated whole blood, elevated MPO antigen levels inversely correlated with the ability of tinzaparin to inhibit 22Rv1-induced thrombin generation. CONCLUSIONS: Myeloperoxidase release may partially attenuate the anticoagulant activity of trough levels of dalteparin and tinzaparin in the context of paraneoplastic leukocyte activation. However, this effect is likely not sufficient to explain the improved efficacy of rivaroxaban, and possibly other oral factor Xa inhibitors, in CAT treatment.

High Aldehyde Dehydrogenase Levels Are Detectable in the Serum of Patients with Lung Cancer and May Be Exploited as Screening Biomarkers.

OBJECTIVES: Since early detection improves overall survival in lung cancer, identification of screening biomarkers for patients at risk represents an area of intense investigation. Tumor liberated protein (TLP) has been previously described as a tumor-associated antigen (complex) present in the sera from lung cancer patients. Here, we set out to identify the nature of TLP to develop this as a potential biomarker for lung cancer screening. MATERIALS AND METHODS: Beginning from the peptide epitope RTNKEASI previously identified from the TLP complex, we produced a rabbit anti-RTNKEASI serum and evaluated it in the lung cancer cell line A549 by means of immunoblot and peptide completion assay (PCA). The TLP sequence identification was conducted by mass spectrometry. The detected protein was, then, analyzed in patients with non-small cell lung cancer (NSCLC) and benign lung pathologies and healthy donors, by ELISA. RESULTS: The anti-RTNKEASI antiserum detected and immunoprecipitated a 55 kDa protein band in the lysate of A549 cells identified as aldehyde dehydrogenase isoform 1A1, revealing the molecular nature of at least one component of the previously described TLP complex. Next, we screened blood samples from a non-tumor cohort of 26 patients and 45 NSCLC patients with different disease stages for the presence of ALDH1A1 and global ALDH. This analysis indicated that serum positivity was highly restricted to patients with NSCLC (ALDH p < 0.001; ALDH1A1 p=0.028). Interestingly, the global ALDH test resulted positive in more NSCLC samples compared to the ALDH1A1 test, suggesting that other ALDH isoforms might add to the sensitivity of the assay. CONCLUSION: Our data indicate that ALDH levels are elevated in the sera of NSCLC patients, even with early stage disease, and may thus be evaluated as part of a marker panel for non-invasive detection of NSCLC.

Low-Molecular-Weight Heparin in Cancer Patients: Overview and Indications.

Although venous thromboembolism (VTE) is a well-known cause of death in patients with cancer, both its treatment and prevention remain a challenge in daily practice. Direct oral anticoagulants have emerged as safe and efficacious alternatives to vitamin K antagonists in the general population, and recent clinical trials also support their use in select patients with cancer-associated VTE. Despite this, low-molecular-weight heparins (LMWHs), a comparatively ancient class of antithrombotic drugs, remain the anticoagulants of choice in many indications relevant to modern haematology and oncology. In addition to the treatment of established VTE, these indications include VTE prophylaxis in surgical or acutely ill, hospitalized medical cancer patients as well as the prevention of VTE in high-risk patients undergoing ambulatory chemotherapy. In a constantly changing landscape of approved anticancer agents, this review article summarizes pivotal clinical trial data and guideline recommendations regarding the use of LMWH in haematological and oncological patients, who constitute a highly vulnerable patient population due to their increased risk for both bleeding and VTE recurrence.

Lapatinib.

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinases plays an important role in the biology of many cancers. In breast and gastrointestinal cancer, and at lower rates also in additional tumor types, HER2 and its homo- or heterodimerization with HER1 or HER3 are essential for cancer cell growth and survival. Breast cancer patients overexpressing HER2 have a more aggressive course of their disease. The poor prognosis associated with HER2 overexpression can be substantially improved by adding HER2-targeted therapy to standard of care using the monoclonal antibody trastuzumab. Lapatinib, an oral dual tyrosine kinase inhibitor, blocks HER1 and HER2 tyrosine kinase activity by binding to the ATP-binding site of the receptor's intracellular domain, resulting in inhibition of tumor cell growth. Lapatinib is generally well tolerated with diarrhea being the most common adverse effect. However, although being mainly of mild to moderate severity, interruption or discontinuation of treatment has been reported in a substantial proportion of patients in clinical trials. In 2007, lapatinib has been approved in combination with capecitabine in patients with advanced HER2-positive breast cancer upon progressive disease following standard therapy with anthracyclines, taxanes, and trastuzumab. In 2013, the approval was extended to a chemotherapy-free combination with trastuzumab for patients with metastatic HER2-positive, hormone receptor-negative breast cancer progressing on prior trastuzumab and chemotherapy. Since 2010, lapatinib is approved in combination with letrozole in the treatment of postmenopausal women with advanced HER2- and hormone receptor-positive breast cancer. In contrast, in first-line cytotoxic-based therapy of both early and advanced HER2-positive breast cancer, data from clinical trials did not provide evidence of additional benefit of lapatinib compared to trastuzumab. Moreover, over the past few years, novel HER2-targeted drugs, either alone or as a combined anti-HER2 approach, have been extensively evaluated, demonstrating a more favorable outcome. Also, neither in first- nor second-line treatment of advanced gastric cancer, lapatinib has been proven to be superior compared to trastuzumab as hitherto standard of care HER2 blockade. Therefore, lapatinib has become somewhat less important in patients with HER2-positive breast cancer during the past 10 years since its first introduction. Nevertheless, consideration of treatment with lapatinib appears to be reasonable in selected patients not only in the approved applications but also beyond, and further indications such as HER2-positive refractory metastatic colorectal cancer may arise in future. Also, lapatinib may have distinct advantages over antibodies in targeting truncated HER2 and crossing the blood-brain barrier. Finally, the favorable cardiac toxicity profile of lapatinib makes it an attractive alternative to trastuzumab-based regimens in patients at risk for cardiac events.

Management of cancer-associated venous thromboembolism - a case-based practical approach.

In patients with solid tumours or haematological malignancies, venous thromboembolism (VTE) is a leading cause of death and significantly contributes to morbidity and healthcare resource utilization. Current practice guidelines recommend long-term anticoagulation with low-molecular-weight heparin (LMWH) as the treatment of choice for cancer-associated VTE, based on clinical trial data showing an overall improved safety and efficacy profile of LMWH compared to vitamin K antagonists. However, several open questions remain, e. g. with regard to the intensity and duration of LMWH therapy; moreover, recent real-world evidence indicates that adherence to parenteral anticoagulation with LMWH over the course of treatment is poor in clinical practice. In this regard, the direct oral factor Xa or thrombin inhibitors (DOACs) have emerged as potential alternatives in the management of patients with cancer-associated VTE, albeit findings from randomized controlled studies with a direct head-to-head comparison of DOACs with LMWH, the current standard of care, are still lacking. Based on the case of a lymphoma patient experiencing symptomatic pulmonary embolism during immunochemotherapy, this article aims at both highlighting the current state-of-the-art approach to cancer-associated VTE and pointing out some of the unresolved, controversial issues clinicians have to face when taking care of haematology and oncology patients with already established or with high risk of developing VTE. These issues include the management of patients with incidental pulmonary embolism or thrombocytopenia, the use of DOACs, and the initiation of pharmacological thromboprophylaxis in non-surgical cancer patients.

Direct oral anticoagulants for the treatment of cancer-associated venous thromboembolism. What do we know so far?

Cancer patients with venous thromboembolism (VTE) are at increased risk for both bleeding and VTE recurrence. Anticoagulation with low-molecular-weight heparin (LMWH) is the standard of care during the initial and long-term treatment phase (i.e. during the first 3 - 6 months of therapy) based on its overall beneficial safety and efficacy profile compared to vitamin K antagonists (VKAs). The direct oral anticoagulants (DOACs) rivaroxaban, apixaban, edoxaban, and dabigatran are approved for the treatment of acute VTE, and the combined six phase-3 trials have included > 1500 patients with active cancer, as defined by variable selection criteria. Subgroup analyses of these patients, either pooled or separately reported, suggest that DOACs could be a safe and efficacious alternative to VKA therapy for the treatment of cancer-associated VTE. However, the populations of cancer patients included in the DOAC and LMWH trials are not comparable with regard to mortality and VTE risk, and no specific data from direct head-to-head comparisons of DOACs with LMWHs are currently available. The use of DOACs for the management of VTE in cancer is thus not recommended by clinical practice guidelines.

Monitoring multiple myeloma by next-generation sequencing of V(D)J rearrangements from circulating myeloma cells and cell-free myeloma DNA.

Recent studies suggest that circulating tumor cells and cell-free DNA may represent powerful non-invasive tools for monitoring disease in patients with solid and hematologic malignancies. Here, we conducted a pilot study in 27 myeloma patients to explore the clonotypic V(D)J rearrangement for monitoring circulating myeloma cells and cell-free myeloma DNA. Next-generation sequencing was used to define the myeloma V(D)J rearrangement and for subsequent peripheral blood tracking after treatment initiation. Positivity for circulating myeloma cells/cell-free myeloma was associated with conventional remission status (P<0.001) and 91% of non-responders/progressors versus 41% of responders had evidence of persistent circulating myeloma cells/cell-free myeloma DNA (P<0.001). About half of the partial responders showed complete clearance of circulating myeloma cells/cell-free myeloma DNA despite persistent M-protein, suggesting that these markers are less inert than the M-protein, rely more on cell turnover and, therefore, decline more rapidly after initiation of effective treatment. Positivity for circulating myeloma cells and for cell-free myeloma DNA were associated with each other (P=0.042), but discordant in 30% of cases. This indicates that cell-free myeloma DNA may not be generated entirely by circulating myeloma cells and may reflect overall tumor burden. Prospective studies need to define the predictive potential of high-sensitivity determination of circulating myeloma cells and DNA in the monitoring of multiple myeloma.

Cetuximab Resistance in Head and Neck Cancer Is Mediated by EGFR-K521 Polymorphism.

Head and neck squamous cell carcinomas (HNSCC) exhibiting resistance to the EGFR-targeting drug cetuximab poses a challenge to their effective clinical management. Here, we report a specific mechanism of resistance in this setting based upon the presence of a single nucleotide polymorphism encoding EGFR-K521 (K-allele), which is expressed in >40% of HNSCC cases. Patients expressing the K-allele showed significantly shorter progression-free survival upon palliative treatment with cetuximab plus chemotherapy or radiation. In several EGFR-mediated cancer models, cetuximab failed to inhibit downstream signaling or to kill cells harboring a high K-allele frequency. Cetuximab affinity for EGFR-K521 was reduced slightly, but ligand-mediated EGFR activation was intact. We found a lack of glycan sialyation on EGFR-K521 that associated with reduced protein stability, suggesting a structural basis for reduced cetuximab efficacy. CetuGEX, an antibody with optimized Fc glycosylation targeting the same epitope as cetuximab, restored HNSCC sensitivity in a manner associated with antibody-dependent cellular cytotoxicity rather than EGFR pathway inhibition. Overall, our results highlight EGFR-K521 expression as a key mechanism of cetuximab resistance to evaluate prospectively as a predictive biomarker in HNSCC patients. Further, they offer a preclinical rationale for the use of ADCC-optimized antibodies to treat tumors harboring this EGFR isoform. Cancer Res; 77(5); 1188-99. ©2016 AACR.

Direct oral anticoagulants for the treatment of cancer-associated venous thromboembolism.

Cancer patients with venous thromboembolism (VTE) are at increased risk for both bleeding and VTE recurrence. Anticoagulation with low-molecular-weight heparin (LMWH) is the standard of care during the initial and longterm treatment phase (i.e. during the first 3 - 6 months of therapy) based on its overall beneficial safety and efficacy profile compared to vitamin K antagonists (VKAs). The direct oral anticoagulants (DOACs) rivaroxaban, apixaban, edoxaban, and dabigatran are approved for the treatment of acute VTE, and the combined six phase-3 trials have included > 1500 patients with active cancer, as defined by variable selection criteria. Subgroup analyses of these patients, either pooled or separately reported, suggest that DOACs could be a safe and efficacious alternative to VKA therapy for the treatment of cancer-associated VTE. However, the populations of cancer patients included in the DOAC and LMWH trials are not comparable with regard to mortality and VTE risk, and no specific data from direct head-to-head comparisons of DOACs with LMWHs are currently available. The use of DOACs for the management of VTE in cancer is thus not recommended by clinical practice guidelines.

Liquid biopsy monitoring uncovers acquired RAS-mediated resistance to cetuximab in a substantial proportion of patients with head and neck squamous cell carcinoma.

Resistance to epidermal growth factor receptor (EGFR)-targeted therapy is insufficiently understood in head and neck squamous cell carcinoma (HNSCC), entailing the lack of predictive biomarkers.Here, we studied resistance-mediating EGFR ectodomain and activating RAS mutations by next-generation sequencing (NGS) of cell lines and tumor tissue of cetuximab-naïve patients (46 cases, 12 cell lines), as well as liquid biopsies taken during and after cetuximab/platinum/5-fluorouracil treatment (20 cases). Tumors of cetuximab-naïve patients were unmutated, except for HRAS mutations in 4.3% of patients. Liquid biopsies revealed acquired KRAS, NRAS or HRAS mutations in more than one third of patients after cetuximab exposure. 46% of patients with on-treatment disease progression showed acquired RAS mutations, while no RAS mutations were found in the non-progressive subset of patients, indicating that acquisition of RAS mutant clones correlated significantly with clinical resistance (Chi square p=0.032). The emergence of mutations preceded clinical progression in half of the patients, with a maximum time from mutation detection to clinical progression of 16 weeks.RAS mutations account for acquired resistance to EGFR-targeting in a substantial proportion of HNSCC patients, even though these tumors are rarely mutated at baseline. Liquid biopsies may be used for mutational monitoring to guide treatment decisions.

Right Atrial Thrombosis in Antiphospholipid Syndrome with Secondary Immune Thrombocytopenia.

Background Antiphospholipid syndrome (APS) is an acquired thrombophilia that can be associated with decreased platelet counts. Case A 67-year-old woman presented with thrombocytopenia and a symptomatic right atrial mass suspicious of cardiac myxoma. Prolongation of the activated partial thromboplastin time (aPTT) was caused by a strong lupus anticoagulant, and bone marrow cytology was consistent with accelerated platelet clearance. The patient underwent uneventful resection of the atrial tumor, which turned out to be a calcified fibrin-rich thrombus. Definitive APS was diagnosed and long-term anticoagulation recommended. Conclusion When evaluating patients with right atrial masses, findings of thrombocytopenia and/or aPTT prolongation should raise the suspicion of APS-associated thrombosis.

Clinical Evidence that Coagulation Activation Drives Cancer Progression--a Report of 2 Cases.

BACKGROUND: Tissue factor (TF), the principal initiator of the extrinsic coagulation pathway, is expressed by many tumors and can be released into the bloodstream on plasma microparticles (MPs). Experimental studies indicate that TF may facilitate hematogenous metastasis by promoting tumor cell-induced microvascular thrombosis, but clinical data supporting this hypothesis is sparse. CASE REPORTS: Here, we report 2 unusual cases of rapidly progressive solid malignancies (gastric and urothelial carcinoma). In both patients, cancer cell dissemination with diffuse bone marrow involvement was either strongly suggested by leukoerythroblastic changes on peripheral blood smear or directly proven by positive findings on aspiration cytology. Furthermore, laboratory evidence of thrombotic microangiopathy (TMA) and disseminated intravascular coagulation was accompanied by new-onset severe pulmonary hypertension and a hemolytic uremic syndrome-like disorder in the gastric and the urothelial carcinoma patient, respectively. TF-specific procoagulant activity of isolated plasma MPs, as assessed by single-stage clotting assay, was dramatically increased in both patients compared to healthy controls (21- and 55-fold), and primary tumor samples stained strongly positive for TF by immunohistochemistry. CONCLUSION: TMA was likely caused by TF-triggered tumor cell embolization in both patients. Further clinical evidence is thus provided that TF directly links coagulation activation to cancer cell dissemination.

Hospital population screening reveals overrepresentation of CD5(-) monoclonal B-cell lymphocytosis and monoclonal gammopathy of undetermined significance of IgM type.

Monoclonal B-cell lymphocytosis (MBL) and monoclonal gammopathy of undetermined significance (MGUS) result from clonal expansions of mature B or plasma cells. Here, we set out to determine the immunophenotypic/monoclonal immunoglobulin (M protein) features and co-prevalence of MBL and MGUS in a hospital-based cohort of 1909 non-hematooncological patients. Of the evaluable cases, 3.8 % showed evidence for MBL by immunophenotyping, while 9.8 % were screened positive for M protein by immunofixation. With six concomitant cases (0.4 %), MBL and MGUS were not statistically associated. At least in two of these coincident cases, MBL and MGUS were of different clonal origin since both clones had divergent light chain restriction. CD5(-) MBL (57.1 %) and IgM+ MGUS (24.7 %) were strikingly overrepresented compared to population-based screenings and did not progress to overt lymphoma or myeloma during the observation period (mean follow-up of 117 weeks or 110 weeks, respectively). Prevalence and phenotypes suggest that a substantial proportion of incidental MBL and MGUS in hospitalized patients may be attributed to transiently expanded B-cell clones in the context of disease-related immune stimulation rather than reflecting veritable precursors of clonal B-cell malignancies.