Activation of complement system in adult T-cell leukemia (ATL) occurs mainly through lectin pathway: A serum proteomic approach using mass spectrometry

Proteomic analysis of adult T-cell leukemia/lymphoma: A biomarker identification strategy based on preparation and in-solution digestion methods of total proteins

Adult T-cell leukemia/lymphoma (ATL), caused by human T-cell leukemia virus type-1 (HTLV-1) infection, is a malignant hematologic cancer that remains difficult to cure. We herein established a biomarker identification strategy based on the total cell proteomics of cultured ATL cells to search for novel ATL biomarkers. Four protocols with a combination of selected conditions based on lysis buffers and addition agents for total cell proteomics were used for a differential analysis between the ATL cell group (consisting of 11 cell lines), HTLV-1-infected cell group (consisting of 6 cell lines), and HTLV-1-negative cell group (consisting of 6 cell lines). In the analysis, we identified 24 and 27 proteins that were significantly increased (ratio ≥2.0, p < 0.05) and decreased (ratio ≤ 0.5, p < 0.05), respectively, in the ATL group. Previously reported CCL3 and CD30/TNFRSF8 were confirmed to be among significantly increased proteins. Furthermore, correlation analysis between identified proteins and Tax suggested that RASSF2 and GORASP2 were candidates of novel Tax-regulated factors. The biomarker identification strategy established herein is expected to contribute to the identification of biomarkers for ATL and other diseases.

Onconephrology and Thrombotic Microangiopathy: Looking Beyond the Horizon

Thrombotic microangiopathies (TMAs) represent a complex interaction of endothelial and podocyte biology, nephron physiology, complement genetics, and oncologic therapies with host immunology. The complexity of various factors, such as molecular causes, genetic expressions, and immune system mimicking, along with incomplete penetrance, make it difficult to find a straightforward solution. As a result, there may be variations in diagnosis, study, and treatment approaches, and achieving a consensus can be challenging. Here, we review the molecular biology, pharmacology, immunology, molecular genetics, and pathology of the various TMA syndromes in the setting of cancer. Controversies in etiology, nomenclature, and points requiring further clinical, translational, and bench research are discussed. Complement-mediated TMAs, chemotherapy drug-mediated TMAs, TMAs in monoclonal gammopathy, and other TMAs central to onconephrology practice are reviewed in detail. In addition, established and emerging therapies within the US Food and Drug Administration pipeline subsequently are discussed. Finally, a comprehensive review of critical areas of onconephrology clinical practice is presented as practical value to the clinical practitioner and seeds of investigation to be sown among the community of atypical hemolytic uremic syndrome researchers.

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is a heterogeneous group of diseases that result in a common pathology, thrombotic microangiopathy, which is classically characterised by the triad of non-immune microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. In this Seminar, different causes of HUS are discussed, the most common being Shiga toxin-producing Escherichia coli HUS. Identifying the underlying thrombotic microangiopathy trigger can be challenging but is imperative if patients are to receive personalised disease-specific treatment. The quintessential example is complement-mediated HUS, which once carried an extremely high mortality but is now treated with anti-complement therapies with excellent long-term outcomes. Unfortunately, the high cost of anti-complement therapies all but precludes their use in low-income countries. For many other forms of HUS, targeted therapies are yet to be identified.

Onconephrology: The intersections between the kidney and cancer

Onconephrology is a new subspecialty of nephrology that recognizes the important intersections of kidney disease with cancer. This intersection takes many forms and includes drug-induced nephrotoxicity, electrolyte disorders, paraneoplastic glomerulonephritis, and the interactions of chronic kidney disease with cancer. Data clearly demonstrate that, when patients with cancer develop acute or chronic kidney disease, outcomes are inferior, and the promise of curative therapeutic regimens is lessened. This highlights the imperative for collaborative care between oncologists and nephrologists in recognizing and treating kidney disease in patients with cancer. In response to this need, specific training programs in onconephrology as well as dedicated onconephrology clinics have appeared. This comprehensive review covers many of the critical topics in onconephrology, with a focus on acute kidney injury, chronic kidney disease, drug-induced nephrotoxicity, kidney disease in stem cell transplantation, and electrolyte disorders in patients with cancer.

The Activation of Prothrombin Seems to Play an Earlier Role than the Complement System in the Progression of Colorectal Cancer: A Mass Spectrometry Evaluation

Colorectal cancer (CRC) is the second cause of death in men and the third in women. This work deals with the study of the low molecular weight protein fraction of sera from patients who underwent surgery for CRC and who were followed for several years thereafter. MALDI-TOF MS was used to identify serum peptidome profiles of healthy controls, non-metastatic CRC patients and metastatic CRC patients. A multiple regression model was applied to signals preliminarily selected by SAM analysis to take into account the age and gender differences between the groups. We found that, while a signal m/z 2021.08, corresponding to the C3f fragment of the complement system, appears significantly increased only in serum from metastatic CRC patients, a m/z 1561.72 signal, identified as a prothrombin fragment, has a significantly increased abundance in serum from non-metastatic patients as well. The findings were also validated by a bootstrap resampling procedure. The present results provide the basis for further studies on large cohorts of patients in order to confirm C3f and prothrombin as potential serum biomarkers. Thus, new and non-invasive tests might be developed to improve the classification of colorectal cancer.

Complement in cancer: untangling an intricate relationship

In tumour immunology, complement has traditionally been considered as an adjunctive component that enhances the cytolytic effects of antibody-based immunotherapies, such as rituximab. Remarkably, research in the past decade has uncovered novel molecular mechanisms linking imbalanced complement activation in the tumour microenvironment with inflammation and suppression of antitumour immune responses. These findings have prompted new interest in manipulating the complement system for cancer therapy. This Review summarizes our current understanding of complement-mediated effector functions in the tumour microenvironment, focusing on how complement activation can act as a negative or positive regulator of tumorigenesis. It also offers insight into clinical aspects, including the feasibility of using complement biomarkers for cancer diagnosis and the use of complement inhibitors during cancer treatment.

Complement the hemostatic system: an intimate relationship

The complement system is important part of our innate immune system and interacts directly with the hemostatic system. Disorders of complement activation or dysregulation resulting in excess complement generation, such as Paroxysmal Nocturnal Hemoglobinuria (PNH), atypical Hemolytic uremic Syndrome (aHUS) and antiphospholipid syndrome (APLS) have been associated with significant thrombophilia. Terminal Complement (C5b-9) deposition on endothelial and tumor cell membranes has also been reported in a variety of cancer. Recent developments in complement inhibition have given us new insights into the mechanism of thrombosis in these disorders.

A PSA-guided approach for a better diagnosis of prostatic adenocarcinoma based on MALDI profiling and peptide identification

BACKGROUND

Prostate cancer (PCa) is the second cause of mortality in men worldwide. The prostate-specific antigen (PSA) test is routinely adopted in diagnosis; nevertheless more reliable biomarkers are continuously under investigation by monitoring the release of molecules into the bloodstream. The serum protein profiles appear to provide cancer-specific fingerprints that help to discriminate patients (especially with low PSA level) from controls, improving the performance of existing clinical tests.

METHODS

Samples from healthy controls and PCa patients with low (≤4 ng/mL) and high PSA (>4 ng/mL) levels were analyzed by MALDI profiling, and by a multi fractionation approach coupled to ESI-MS for peaks identification.

RESULTS

MALDI profiling achieved to detect 10 and 14 changed peaks (p-value <0.05), respectively, in PCa patients with low and high PSA versus controls. In particular, a peak identified as C3f fragment, resulted overexpressed in low PSA PCa patients.

CONCLUSIONS

PSA test, coupled to MALDI profiling, is able to detect changes, specifically related to PCa, in low molecular weight protein range. Furthermore, for the first time in prostate cancer research, the identification and quantification of the small peptide C3f appears to be relevant for the detection of false negatives, providing an additive diagnostic power to PSA (p<0.01) and suggesting its use in clinical tests.

Role of C5b-9 complement complex and response gene to complement-32 (RGC-32) in cancer

Complement system activation plays an important role in both innate and acquired immunity, with the activation of complement and the subsequent formation of C5b-9 terminal complement complex on cell membranes inducing target cell death. Recognition of this role for C5b-9 leads to the assumption that C5b-9 might play an antitumor role. However, sublytic C5b-9 induces cell cycle progression by activating signal transduction pathways and transcription factors in cancer cells, indicating a role in tumor promotion for this complement complex. The induction of the cell cycle by C5b-9 is dependent upon the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/FOXO1 and ERK1 pathways in a Gi protein-dependent manner. C5b-9 also induces response gene to complement (RGC)-32, a gene that plays a role in cell cycle promotion through activation of Akt and the CDC2 kinase. RGC-32 is expressed by tumor cells and plays a dual role in cancers, in that it has both a tumor suppressor role and tumor-promoting activity. Thus, through the activation of tumor cells, the C5b-9-mediated induction of the cell cycle plays an important role in tumor proliferation and oncogenesis.

Serum proteomic profiling for the early diagnosis of colorectal cancer

No ideal serum biomarker currently exists for the early diagnosis of colorectal cancer (CRC). Magnetic bead-based fractionation coupled with MALDI-TOF MS was used to screen serum samples from CRC patients, healthy controls, and other cancer patients. A diagnostic model with five proteomic features (m/z 1778.97, 1866.16, 1934.65, 2022.46, and 4588.53) was generated using Fisher algorithm with best performance. The Fisher-based model could discriminate CRC patients from the controls with 100% (46/46) sensitivity and 100% (35/35) specificity in the training set, 95.6% (43/45) sensitivity and 83.3% (35/42) specificity in the test set. We further validated the model with 94.4% (254/269) sensitivity and 75.5% (83/110) specificity in the external independent group. In other cancers group, the Fisher-based model classified 25 of 46 samples (54.3%) as positive and the other 21 as negative. With FT-ICR-MS, the proteomic features of m/z 1778.97, 1866.16, 1934.65, and 2022.46, of which intensities decreased significantly in CRC, were identified as fragments of complement C3f. Therefore, the Fisher-based model containing five proteomic features was able to effectively differentiate CRC patients from healthy controls and other cancers with a high sensitivity and specificity, and may be CRC-specific. Serum complement C3f, which was significantly decreased in CRC group, may be relevant to the incidence of CRC.

Complement C3f serum levels may predict breast cancer risk in women with gross cystic disease of the breast

Gross cystic disease (GCDB) is a breast benign condition predisposing to breast cancer. Cryopreserved sera from GCDB patients, some of whom later developed a cancer (cases), were studied to identify potential risk markers. A MALDI-TOF mass spectrometry analysis found several complement C3f fragments having a significant increased abundance in cases compared to controls. After multivariate analysis, the full-length form of C3f maintained a predictive value of breast cancer risk. Higher levels of C3f in the serum of women affected by a benign condition like GCDB thus appears to be correlated to the development of breast cancer even 20 years later.

BIOLOGICAL SIGNIFICANCE

Increased complement system activation has been found in the sera of women affected by GCDB who developed a breast cancer, even twenty or more years later. C3f may predict an increased breast cancer risk in the healthy population and in women affected by predisposing conditions.

ProteoMiner™ and SELDI-TOF-MS: a robust and highly reproducible combination for biomarker discovery from whole blood serum

Surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS) has been recognized as an appropriate technology for biomarker discovery. Nevertheless, whenever human blood serum is studied, its sensitivity is restricted due to the wide dynamic range of serum protein concentrations. In this context, sample pre-fractionation targeting the low abundant proteins may help to overcome these limitations. Here, we evaluate the combination of ProteoMiner™ pre-fractionation and SELDI based protein profiling. We introduce a simplified workflow and demonstrate the high sensitivity and reproducibility of this combined profiling approach. Our analyses show that this combination is suitable for large-scale serum proteome profiling studies yielding reliable and reproducible results.

Mass spectrometry-based proteomics and its potential use in haematological research

In the last decade proteomics has made great progress reaching throughput and comprehensiveness comparable to genomics technologies. Mass spectrometry plays a key role in proteomics and has become an indispensable method for molecular and cellular biology because many cellular changes in response to internal or external stimuli can only be detected at the proteome level. Furthermore, different from genomics which depends on the availability of DNA or RNA, proteomics is not restricted to cellular samples, but also allows the analysis of biological fluids like serum, plasma or urine. This article provides an overview of the recent developments in proteomics techniques useful for haematological research.