Group items tagged

Eighty-five percent of lung cancers are non-small-cell lung cancer (NSCLC)

environmental factors, living habits, genetic mutations, dysfunction of the immune system and so on

special tumor immune microenvironment

cytotoxic T lymphocyte-associated antigen 4 (CLTA-4), Programmed death-1 (PD-1) and its ligands PD-L1 (B7H1) and PD-L2 (B7-DC)

CTLA-4 regulates T cell activity in the early stage predominantly, and PD-1 mainly limits the activity of T-cell in the tumor microenvironment at later stage of tumor growth

PD‐L1 on cancer cells could induce T‐cell apoptosis through

The hydroperoxyl radical () plays an important role in the chemistry of lipid peroxidation

The is a much stronger oxidant than superoxide anion-radical

Lipid peroxidation can be described generally as a process under which oxidants such as free radicals or nonradical species attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids (PUFAs) that involve hydrogen abstraction from a carbon, with oxygen insertion resulting in lipid peroxyl radicals and hydroperoxides as described previously

under medium or high lipid peroxidation rates (toxic conditions) the extent of oxidative damage overwhelms repair capacity, and the cells induce apoptosis or necrosis programmed cell death

The overall process of lipid peroxidation consists of three steps: initiation, propagation, and termination

Once lipid peroxidation is initiated, a propagation of chain reactions will take place until termination products are produced.

The main primary products of lipid peroxidation are lipid hydroperoxides (LOOH)

Among the many different aldehydes which can be formed as secondary products during lipid peroxidation, malondialdehyde (MDA), propanal, hexanal, and 4-hydroxynonenal (4-HNE) have been extensively studied

MDA has been widely used for many years as a convenient biomarker for lipid peroxidation of omega-3 and omega-6 fatty acids because of its facile reaction with thiobarbituric acid (TBA)

MDA is one of the most popular and reliable markers that determine oxidative stress in clinical situations [53], and due to MDA’s high reactivity and toxicity underlying the fact that this molecule is very relevant to biomedical research community

4-HNE is considered as “second toxic messengers of free radicals,” and also as “one of the most physiologically active lipid peroxides,” “one of major generators of oxidative stress,” “a chemotactic aldehydic end-product of lipid peroxidation,” and a “major lipid peroxidation product”

MDA is an end-product generated by decomposition of arachidonic acid and larger PUFAs

Identifying in vivo MDA production and its role in biology is important as indicated by the extensive literature on the compound (over 15 800 articles in the PubMed database using the keyword “malondialdehyde lipid peroxidation” in December 2013)

MDA reactivity is pH-dependent

When pH decreases MDA exists as beta-hydroxyacrolein and its reactivity increases

MAA adducts are shown to be highly immunogenic [177–181]. MDA adducts are biologically important because they can participate in secondary deleterious reactions (e.g., crosslinking) by promoting intramolecular or intermolecular protein/DNA crosslinking that may induce profound alteration in the biochemical properties of biomolecules and accumulate during aging and in chronic diseases

MDA is an important contributor to DNA damage and mutation

This MDA-induced DNA alteration may contribute significantly to cancer and other genetic diseases.

Dietary intake of certain antioxidants such as vitamins was associated with reduced levels of markers of DNA oxidation (M1dG and 8-oxodG) measured in peripheral white blood cells of healthy subjects, which could contribute to the protective role of vitamins on cancer risk

4-HNE is an extraordinarily reactive compound

surgery per se can promote cancer metastasis through a series of local and systemic events

surgery results in a serious wound that disrupts the structural barrier preventing the outspreading of cancer cells, change the properties of the cancer cells and stromal cells remaining in the tumor microenvironment, or impairs the host defense systems against cancers

After the primary tumor is surgically removed, the metastases can start to grow vigorously via neoangiogenesis because the circulating inhibitors disappear

infection and inflammation during the postoperative period have been reported to increase the risk of cancer recurrence in patients

Surgeons have long suspected that surgery, even if it is a necessary step in cancer treatment, facilitates cancer metastasis

Surgery-induced cancer metastasis has been well established in animal models

tumor cell dissemination, tumor-favoring immune responses, and neoangiogenesis

the surgical resection of primary tumors is beneficial is controversial

CTCs abruptly increase just after surgery

Even externally palpitating tumors for diagnosis could increase the numbers of CTCs in skin cancer and breast cancer

excessive glucocorticoids negatively modulate immune functions

immune surveillance against tumors is considered to be impaired by surgical stress

In addition to glucocorticoids, during stimulation of the HPA axis, the catecholamine hormones epinephrine and norepinephrine are released from the adrenal medulla

NK cell suppression may be attributed to increased levels of catecholamines as well as glucocorticoids

In mice bearing a primary tumor, it was observed that the removal of the primary tumor facilitated the growth of highly vascularized metastases

primary tumors may secrete angiogenic inhibitors as well as angiogenic activators

second phase of tumor recurrence and metastasis, which are newly acquired events, rather than just outcomes of incomplete treatment.

double-edged sword

HIF-1 in neutrophils plays a critical role in NETosis and bacteria-killing activity

neutrophils play various roles in the initiation and progression of cancer

NETosis

many inflammatory and neoplastic diseases

formation of neutrophil extracellular traps (NETs), which are large extracellular complexes composed of chromatin and cytoplasmic/granular proteins1

NETosis has been highlighted as an inflammatory event that promotes cancer metastasis

Once activated, neutrophils produce intracellular precursors by using DNA, histones, and granular and cytoplasmic proteins and then spread the mature form of NETs out around themselves

A series of these events is called NETosis.

neutrophil elastase, myeloperoxidase, cathepsin G, proteinase 3, lactoferrin, gelatinase, lysozyme C, calprotectin, neutrophil defensins, and cathelicidins

innate immune response against infection

Neutrophils are the most abundant type of granulocytes, comprising 40–70% of all white blood cells

two types of NEToses, suicidal (or lytic) NETosis and vital NETosis

Suicidal NETosis mainly depends on the production of reactive oxygen species (ROS)

Since neutrophils die during this process, it is called suicidal NETosis.

vital NETosis

vital NETosis occurs independently of ROS production

Vital NETosis can be induced by Gram-negative bacteria. LPS

NETs are present in a variety of cancers, such as lung cancer, colon cancer, ovarian cancer, and leukemia

neutrophils actively undergo NETosis in the tumor microenvironment

Hypoxia

NETosis plays a pivotal role in noninfectious autoimmune diseases,

cytokines

tumor-derived proteases

tumor exosomes

NETosis generally actively progresses in the tumor microenvironment.

the proliferative cytokines TGFβ and IL-10 and the angiogenic factor VEGF are representative of neutrophil-derived tissue repair proteins.

NETosis is a defense system to protect the body from invading pathogens

when neutrophils are excessively stimulated, they produce excess NETs, thereby leading to pathological consequences

plasma levels of NETosis markers are elevated after major surgeries

local invasion, intravasation into the blood or lymphatic vessels, escape from the immune system, anchoring to capillaries in target organs, extravasation into the organs, transformation from dormant cells to proliferating cells, colonization to micrometastases, and growth to macrometastases

NETs promote metastasis at multiple steps

NETs loosen the ECM and capillary wall to promote the intravasation of cancer cells

NETs and platelets wrap CTCs, which protects them from attack by immune cells and shearing force by blood flow

NETs promote the local invasion of cancer cells by degrading the extracellular matrix (ECM)

neutrophil elastase, matrix metalloproteinase 9, and cathepsin G

NETs also promote the intravasation of cancer cells

millions of tumor cells are released into the circulation every day,

NETs can wrap up CTCs with platelets

β1-integrin plays an important role in the interaction between CTCs and NETs

NET-platelet-CTC aggregates.

After metastasizing to distant tissues, tumor cells are often found to remain dormant for a period of time and unexpectedly regrow late

NETs are believed to participate in the reactivation of dormant cancer cells in metastatic regions

NET-associated proteases NE and MMP-9 were found to be responsible for the reactivation of dormant cancer cells