Apoptosis and nucleosomes

Circulating Cell-Free DNA in Breast Cancer: Searching for Hidden Information towards Precision Medicine

Simple Summary

Our research focuses in the elucidation of the nature of circulating cell-free DNA (ccfDNA) as a biological entity and its exploitation as a liquid biopsy biomaterial. Working on breast cancer, it became clear that although a promising biosource, its clinical exploitation is burdened mainly by gaps in knowledge about its biology and specific characteristics. The current review covers multiple aspects of ccfDNA in breast cancer. We cover key issues such as quantity, integrity, releasing structures, methylation specific changes, release mechanisms, biological role. Machine learning approaches for analyzing ccfDNA-generated data to produce classifiers for clinical use are also discussed.

Abstract

Breast cancer (BC) is a leading cause of death between women. Mortality is significantly raised due to drug resistance and metastasis, while personalized treatment options are obstructed by the limitations of conventional biopsy follow-up. Lately, research is focusing on circulating biomarkers as minimally invasive choices for diagnosis, prognosis and treatment monitoring. Circulating cell-free DNA (ccfDNA) is a promising liquid biopsy biomaterial of great potential as it is thought to mirror the tumor’s lifespan; however, its clinical exploitation is burdened mainly by gaps in knowledge of its biology and specific characteristics. The current review aims to gather latest findings about the nature of ccfDNA and its multiple molecular and biological characteristics in breast cancer, covering basic and translational research and giving insights about its validity in a clinical setting.

Cell-free circulating tumor DNA analysis for breast cancer and its clinical utilization as a biomarker

Circulating tumor DNA (ctDNA) in the blood of cancer patients contains much information on genetic and epigenetic profiles associated with cancer development, progression, and response to therapy. Analysis of ctDNA provides an opportunity for non-invasive sampling of tumor DNA repetitiously and therefore advance precision medicine. Recent development in massively parallel sequencing and digital genomic techniques support the analytical and clinical validity of ctDNA as a promising 'liquid biopsy' in human cancer. In this review, we discussed the current status of cell-free ctDNA including ctDNA biology, recently developed techniques for ctDNA detection, breast cancer specific detecting strategies, with a focus on clinical applications of ctDNA-based biomarkers in breast oncology.

Drug-induced subacute cutaneous lupus erythematosus associated with docetaxel chemotherapy: a case report

BACKGROUND

Drug-induced subacute cutaneous lupus erythematosus is an uncommon disorder associated with the use of pharmacological agents including systemic chemotherapy.

CASE PRESENTATION

We report a case of docetaxel-induced subacute cutaneous lupus erythematosus in a 60-year-old Caucasian female with Sjögren's syndrome diagnosed 2 months after receiving docetaxel as part of the adjuvant FEC-D (5-fluorouracil, epirubicin, cyclophosphamide, docetaxel) chemotherapy protocol for early stage breast cancer. Although the exact mechanisms behind the autoimmune response elicited by docetaxel are unclear, the involvement of anti-SSA/Ro antibodies has been implicated.

CONCLUSION

This case highlights the symptom severity and clinical course of docetaxel-induced subacute cutaneous lupus erythematosus, and highlights the importance of recognizing this uncommon but potentially severe chemotherapy-associated cutaneous reaction.

Cell-free nucleic acids as biomarkers in cancer patients

DNA, mRNA and microRNA are released and circulate in the blood of cancer patients. Changes in the levels of circulating nucleic acids have been associated with tumour burden and malignant progression. In the past decade a wealth of information indicating the potential use of circulating nucleic acids for cancer screening, prognosis and monitoring of the efficacy of anticancer therapies has emerged. In this Review, we discuss these findings with a specific focus on the clinical utility of cell-free nucleic acids as blood biomarkers.

Anti-nucleosome and anti-chromatin antibodies are present in active systemic lupus erythematosus but not in the cutaneous form of the disease

The objective of this study is to investigate the presence of anti-nucleosome (anti-NCS) and anti-chromatin (anti-CRT) antibodies in patients with cutaneous lupus erythematosus (CLE) compared with active and inactive systemic lupus erythematosus (SLE). A total of 154 subjects were evaluated: 54 patients presenting CLE, 66 patients with active SLE and 34 with inactive SLE. Lupus activity was assessed using the disease activity index (SLEDAI). Anti-NCS and anti-CRT antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Only one of 54 patients with CLE tested positive for both anti-NCS and anti-CRT antibodies. The prevalence of anti-CRT antibodies was significantly higher in active SLE (84.8%) when compared with inactive SLE (26.4%) and CLE (1.8%) ( P < 0.001). Anti-NCS antibodies were also more prevalent in active SLE patients (74.2%) than inactive SLE (11.7%) and CLE patients (1.8%) ( P < 0.001). The presence of anti-CRT and anti-NCS antibodies was correlated to disease activity in patients with SLE ( r = 0.4937, r = 0.5621, respectively). Furthermore, the detection of both antibodies was correlated with disease activity in patients with SLE who tested negative for anti-dsDNA antibodies ( r = 0.4754 for anti-NCS and r = 0.4281 for anti-CRT). The presence of these two auto-antibodies was strongly associated with renal damage in patients with SLE (OR = 13.1, for anti-CRT antibodies and OR = 25.83, for anti-NCS antibodies). The anti-NCS and anti-CRT antibodies were not found in CLE. In patients with SLE, there is a correlation of these antibodies with disease activity and active nephritis. When compared with anti-dsDNA antibodies, anti-NCS and anti-CRT antibodies were more sensitive in detecting disease activity and kidney damage in lupus patients.

Mitochondrial Extrusion through the cytoplasmic vacuoles during cell death

Under various conditions, noxious stimuli damage mitochondria, resulting in mitochondrial fragmentation; however, the mechanisms by which fragmented mitochondria are eliminated from the cells remain largely unknown. Here we show that cytoplasmic vacuoles originating from the plasma membrane engulfed fragmented mitochondria and subsequently extruded them into the extracellular spaces in undergoing acute tumor necrosis factor alpha-induced cell death in a caspase-dependent fashion. Notably, upon fusion of the membrane encapsulating mitochondria to the plasma membrane, naked mitochondria were released into the extracellular spaces in an exocytotic manner. Mitochondrial extrusion was specific to tumor necrosis factor alpha-induced cell death, because a genotoxic stress-inducing agent such as cisplatin did not elicit mitochondrial extrusion. Moreover, intact actin and tubulin cytoskeletons were required for mitochondrial extrusion as well as membrane blebbing. Furthermore, fragmented mitochondria were engulfed by cytoplasmic vacuoles and extruded from hepatocytes of mice injected with anti-Fas antibody, suggesting that mitochondrial extrusion can be observed in vivo under pathological conditions. Mitochondria are eliminated during erythrocyte maturation under physiological conditions, and anti-mitochondrial antibody is detected in some autoimmune diseases. Thus, elucidating the mechanism underlying mitochondrial extrusion will open a novel avenue leading to better understanding of various diseases caused by mitochondrial malfunction as well as mitochondrial biology.

[Ying-Yang (YY-1) expression and Fas in biopsies of children with type IV lupus nephritis correlates with the clinical condition]

BACKGROUND

It has been demonstrated that Fasmediated apoptosis participates in the physiopathology of lupus nephritis, although it is not clear whether it contributes to the development of the tissue damage.Since YY-1 down regulates Fas in cancer cell lines, it is reasonable to consider that this transcription factor may control Fas expression in lupus nephritis. The objective was to determine the correlation between YY-1 and Fas expression in renal biopsies from children with type IV lupus nephritis, and their association with the clinical condition of the patients.

MATERIAL AND METHODS

Eighteen biopsies from children with type IV lupus nephritis and 5 controls were studied. Fas and YY-1 expression were determined by immunochemistry and quantified by densytometric analysis. The clinical conditions at the moment the biopsy were obtained from the clinical records and the results were analyzed through a one-way ANOVA with p<0.005.

RESULTS

The results of the densytometric analysis showed an inverse relationship between YY-1 and Fas expression. YY-1 was grouped according to the intensity of expression in low, moderate and high and compared with the expression of Fas. The lupus nephritis biopsies, which revealed high expression of YY-1, corresponded to patients with less number of clinical complications,better outcome and fewer alterations on renal function.In contrast, low expression of YY-1 correlated with high Fas expression and worst clinical conditions.

CONCLUSIONS

The present study suggests that YY-1regulates Fas expression in lupus nephritis and that it is associated with the clinical outcome of the patients,although further studies are necessary to determine weather it factor may serve as a prognosis factor. This is the first evidence of YY-1 participation in the physiopathology of lupus nephritis.

Peripheral blood lymphocyte apoptosis and circulating dendritic cells in patients with systemic lupus erythematosus: correlation with immunological status and disease-related symptoms

We investigated in vivo the relationship between the degree of peripheral blood lymphocyte apoptosis and circulating dendritic cells (DC) as well as the immunological status in 45 patients with systemic lupus erythematous (SLE). Apoptosis was detected by phosphatidylserine externalization and assays to detect caspase activation. The total DC count (tDC) and their myeloid, mDC1 (BDCA1+) and mDC2 (BDCA3+), and plasmacytoid, pDC (BDCA3+), subtypes were assessed. Moreover, several immunological parameters, such as complement proteins, interferons (IFN), tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-6 levels were assessed. There were no significant differences in both the intensity of apoptosis and DC counts between active and inactive SLE as well as between untreated patients and those treated with steroids. The incidence of lymphocyte apoptosis correlated positively with T-cell count, both T-helper (p=0.004) and cytotoxic T cells (p=0.001), but not with B or natural killer (NK) cells. The intensity of apoptosis enhanced along with the increase in complement C3 (p=0.016) and decrease in IFN-gamma (p=0.040) levels. The apoptotic cell count correlated with tDC (p=0.031), mDC1 (p=0.007), and pDC (p=0.039) counts. Both tDC and mDC1 counts correlated positively with antinuclear antibody (ANA) titers (p=0.017 and 0.032, respectively). Moreover, tDC correlated with C4 (p=0.039) and pDC with both C3 (p=0.032) and C4 (p=0.007) levels. The DC counts correlated inversely with IFN-gamma (tDC, p=0.038; mDC1, p=0.009), IL-6 (mDC2, p=0.031), or serum IgG levels (tDC, p=0.006; mDC1, p<0.001; mDC2, p=0.001). We found a positive correlation between lymphocyte apoptosis and peripheral blood DC count as well as the level of complement proteins in patients with SLE. The enhanced lymphocyte apoptosis was accompanied by the decrease in concentration of some cytokines, such as IFN-gamma or IL-6, as well as serum IgG level. This finding may reflect pathogenetic events during development of the disease, which include a persistent signal derived from circulating apoptotic lymphocytes, mobilizing the complement system, and attracting peripheral blood DC.

Models of systemic lupus erythematosus: development of autoimmunity following peptide immunizations of noninbred pedigreed rabbits

Reported in this study are the initial results from studies to develop rabbit models of systemic lupus erythematosus (SLE) by immunizations using two distinct peptides on branched polylysine backbones (multiple Ag peptide)-peptides. Eleven rabbits received a peptide from the Sm B/B' spliceosomal complex previously shown to be immunogenic in rabbits, and 13 rabbits received a peptide from the rabbit N-methyl-d-aspartate receptor NR2b. All 24 animals in different generations of pedigreed, noninbred rabbits produced peptide-specific responses. Anti-nuclear autoantibody responses, including anti-dsDNA, were seen in 17 of 24 rabbits. To date, two rabbits have been observed to have seizure-like events and a third nystagmus. A model for eliciting development of SLE in genetically related yet heterogeneous rabbits may more closely resemble development of human SLE than do some models in inbred mice. Through selective breeding, it may also ultimately provide additional information about the genetics and etiology of SLE and serve as a model for assessing new treatment options.

Actin-myosin-based contraction is responsible for apoptotic nuclear disintegration

Membrane blebbing during the apoptotic execution phase results from caspase-mediated cleavage and activation of ROCK I. Here, we show that ROCK activity, myosin light chain (MLC) phosphorylation, MLC ATPase activity, and an intact actin cytoskeleton, but not microtubular cytoskeleton, are required for disruption of nuclear integrity during apoptosis. Inhibition of ROCK or MLC ATPase activity, which protect apoptotic nuclear integrity, does not affect caspase-mediated degradation of nuclear proteins such as lamins A, B1, or C. The conditional activation of ROCK I was sufficient to tear apart nuclei in lamin A/C null fibroblasts, but not in wild-type fibroblasts. Thus, apoptotic nuclear disintegration requires actin-myosin contractile force and lamin proteolysis, making apoptosis analogous to, but distinct from, mitosis where nuclear disintegration results from microtubule-based forces and from lamin phosphorylation and depolymerization.

Nuclear-targeting autoantibodies induced nuclear PARP cleavage accompanied by more pronounced decrease of peripheral white blood cells than Ro/SSA and La/SSB antigen-targeting autoantibodies

Autoantibody production and leukocytopenia may be linked in patients with lupus erythematosus (LE). Unclear is the ability of different autoantibody species to induce apoptosis and cell loss. Laboratory routine analyses (white blood cell counts, autoantibody detection), and flow cytometry (annexin V, CD3, CD4, CD8) have been performed in 126 consecutive LE-patients. Nuclei of PBMC were investigated flow cytometrically for the presence of the 85 kDa poly-(ADP-ribose)-polymerase (PARP) fragment. Peripheral total white blood cells (WBC), lymphocytes, T-cells, CD3+ CD4+, and CD3+ CD8+ cells were significantly decreased in patients with LE (P from 1.2 x 10(-14) to P < .0008). In the presence of either antinuclear (P from 1.2 x 10(-14) to P < .0008) or anti-dsDNA antibodies (P from 2.9 x 10(-12) to P < .007) were significantly diminished. Differences in cell numbers in LE patients with versus without anti-Ro/SSA were less pronounced: significant differences could be only obtained in lymphocytes and T-cells (P < .02). Anti-La/SSB antibodies were accompanied by significant increased leukocytes (P < .02). PARP cleavage (85 kDa) in nuclei was preferentially observed in cases with nuclear targeting autoantibodies. These results indicate that nuclear targeting autoantibodies are associated to lower peripheral blood cells counts than Ro/SSA, and La/SSB cytoplasmic targeting autoantibodies. This provides an explanation for the pathogenesis of cytopenias associated with SLE.