Rat mesothelioma cell proliferation requires p38δ mitogen activated protein kinase and C/EBP-α

PDGFBB facilitates tumorigenesis and malignancy of lung adenocarcinoma associated with PI3K-AKT/MAPK signaling

Lung adenocarcinoma (LUAD) remains one of the most aggressive tumors and the efficacy of conventional treatment has been bleak. Nowadays, gene-targeted therapy has become a new favorite in tumor therapy. Herein, we investigated the effect of platelet derived growth factor BB (PDGFBB) on LUAD. Firstly, PDGFBB was upregulated in LUAD patients and closely linked with poor survival. Furthermore, the expression of PDGFBB and PDGFRα/β in LUAD cells was higher than that in normal lung cells. By loss-of-function with herpes simplex virus (HSV)-PDGFi-shRNA, we found that PDGFBB knockdown caused a significant decrease in proliferation and migration, but evoked apoptosis of LUAD cells in vitro. Conversely, exogenous PDGFBB held adverse effect. Additionally, A549 cells with PDGFBB knockdown had a low probability of tumorigenesis in vivo. Moreover, PDGFBB knockdown restrained the growth of xenografts derived from normal A549 cells. Mechanistically, PDGFBB knockdown suppressed PI3K/AKT and Ras/MAPK signaling, while PDGFBB was the opposite. Therefore, we concluded that PDGFBB might facilitate the tumorigenesis and malignancy of LUAD through its functional downstream nodes-PI3K/AKT and Ras/MAPK signaling, which supported that PDGFBB could serve as a rational therapeutic target for LUAD.

Immunoregulatory actions of calf thymus extract (TFX®) in vitro in relation to its effect on expression of mitogen activated protein kinases

The in vitro immunotropic actions of a calf thymus extract - thymus factor X (TFX®) preparation were investigated. The preparation did not lower the viability of the A549 epithelial cell line and mouse bone marrow cells in the investigated concentration range. TFX® exhibited a co-stimulatory action of concanavalin A (Con A)-induced mouse thymocyte proliferation and partially restored the mitogen-induced proliferation capability of mouse thymocytes exposed to hydrocortisone (HC). The preparation also inhibited Herpes virus-1 (HSV-1) replication in A549 cells when preincubated with the virus and when added to the infected cells. In addition, it weakly inhibited lipopolysaccharide (LPS)-induced TNF α, IL-1β and IL-6 by the THP-1 monocyte cell line. The determination of mitogen activated protein kinase (MAPK) expression in Jurkat T cells revealed strong increases in ERK-2 kinase and p38α subunits. In WEHI 231 immature B cells, TFX® elevated p38α, and had a particularly strong elevating effect on p38γ. In HL-60 myeloblastic cells, the expression of p38α, β and γ was not detectable, almost blocked for p38δ and JNK, but accompanied by an increase in ERK-1. In turn, the effects of TFX® in J744E macrophages resulted in a strong increase in p38γ expression, moderate elevations of ERK and a drop in p38δ. Significant increases in MAPK expression were also found in cells from the lymphoid organs. In the bone marrow cell population, p38α, β and γ, in thymocytes p38α, γ and δ, and in splenocytes p38β and γ, subunit expression was elevated. We conclude that the changes in MAPK expression may be attributed to cell maturation and differentiation, and explain the beneficial therapeutic effects of TFX®.

A cytotoxic effect of human lactoferrin fusion with Fc domain of IgG

Lactoferrin (LTF) is a natural iron-binding protein with a potential for clinical utility in many human immune disorders, including cancer. A fusion of LTF with the Fc domain of IgG2 (FcLTF) was designed with inherent properties of an extended the half-life in circulation. Furthermore, the effects of LTF and FcLTF were assessed for influence on the activity of natural killer (NK) cells isolated from human peripheral blood, on the NK-92 cell line, and on human monocytes. The NK cytotoxic activity induced by LTF and FcLTF was determined against the human leukemia K562 cell line, and also for monocytes, by measuring TNFα and granzyme B production, and in an assay for Jurkat cell viability. Selected gene expression in NK-92 cells and monocytes, induced by LTF and FcLTF, was performed by Real Time PCR. No significant difference was observed in NK-92 cytotoxicity stimulated by LTF and FcLTF. The effects on NK cells isolated from the human peripheral blood were varied, possibly due to the immunoregulatory nature of LTF sensing the immune status of donors. Furthermore, only the FcLTF group strongly stimulated production of TNFα and granzyme B in isolated monocytes. In addition, only supernatants from the monocyte cultures treated with FcLTF decreased the viability of Jurkat cells. The ability of FcLTF to induce TNFα in monocytes was strongly inhibited by anti-CD32 and moderately inhibited by anti-CD14 antibody. Lastly, it was demonstrated that FcLTF, strongly induced expression of PI3K, with subsequent activation of AKT/mTOR signaling pathway. Overall, it was demonstrated that this novel fusion molecule may be a perferred choice for clinical utility than the wild type LTF.

Synthesis, Physicochemical Characteristics and Plausible Mechanism of Action of an Immunosuppressive Isoxazolo[5,4-e]-1,2,4-Triazepine Derivative (RM33)

Previous studies demonstrated strong anti-inflammatory properties of isoxazolo[5,4-e]-1,2,4-triazepine (RM33) in vivo. The aim of this investigation was to describe synthesis, determine physicochemical characteristics, evaluate biological activities in murine and human in vitro models, as well as to propose mechanism of action of the compound. The compound was devoid of cell toxicity up to 100 μg/mL against a reference A549 cell line. Likewise, RM33 did not induce apoptosis in these cells. The compound stimulated concanavalin A (ConA)-induced splenocyte proliferation but did not change the secondary humoral immune response in vitro to sheep erythrocytes. Nevertheless, a low suppressive effect was registered on lipopolysaccharide (LPS)-induced splenocyte proliferation and a stronger one on tumor necrosis factor alpha (TNFα) production by rat peritoneal cells. The analysis of signaling pathways elicited by RM33 in nonstimulated resident cells and cell lines revealed changes associated with cell activation. Most importantly, we demonstrated that RM33 enhanced production of cyclooxygenase 2 in LPS-stimulated splenocytes. Based on the previous and herein presented results, we conclude that RM33 is an efficient, nontoxic immune suppressor with prevailing anti-inflammatory action. Additionally, structural studies were carried out with the use of appropriate spectral techniques in order to unequivocally confirm the structure of the RM33 molecule. Unambiguous assignment of NMR chemical shifts of carbon atoms of RM33 was conducted thanks to full detailed analysis of ¹H, ¹³C NMR spectra and their two-dimensional (2D) variants. Comparison between theoretically predicted chemical shifts and experimental ones was also carried out. Additionally, N-deuterated isotopologue of RM33 was synthesized to eliminate potentially disturbing frequencies (such as NH, NH₂ deformation vibrations) in the carbonyl region of the IR (infrared) spectrum to confirm the presence of the carbonyl group.

A Special View of What Was Almost Forgotten: p38δ MAPK

Simple Summary

p38δ MAPK, as well as the other p38 isoforms, was proposed as a drug target for cancer therapy, owing to its critical roles in cellular signaling. However, herein, we show that p38δ inhibition may be therapeutically beneficial for treatment of specific cancer types, such as skin carcinoma, hepatocellular carcinoma (HCC), head and neck squamous cell carcinoma (HNSCC), cholangiocarcinoma (CC), and breast cancer. This review aims to discuss the roles of p38δ in cancer and summarize the findings of molecules with potential to inhibit p38δ in order to guide the search for new target cancer therapies based on p38δ inhibitors.

Abstract

The p38δ mitogen-activated protein kinase is an important signal transduction enzyme. p38δ has recently emerged as a drug target due to its tissue-specific expression patterns and its critical roles in regulation of cellular processes related to cancer and inflammatory diseases, such as cell proliferation, cell migration, apoptosis, and inflammatory responses. However, potent and specific p38δ inhibitors have not been defined so far. Moreover, in cancer disease, p38δ appears to act as a tumor suppressor or tumor promoter according to cancer and cell type studied. In this review, we outline the current understanding of p38δ roles in each cancer type, to define whether it is possible to delineate new cancer therapies based on small-molecule p38δ inhibitors. We also highlight recent advances made in the design of molecules with potential to inhibit p38 isoforms and discuss structural approaches to guide the search for p38δ inhibitors.

P38 delta MAPK promotes breast cancer progression and lung metastasis by enhancing cell proliferation and cell detachment

The protein p38 mitogen-activated protein kinase delta isoform (p38δ) is a poorly studied member of the MAPK family. Data analysis from The Cancer Genome Atlas (TCGA) database revealed that p38δ is highly expressed in all types of human breast cancers. Using a human breast cancer tissue array, we confirmed elevation in cancer tissue. The breast cancer mouse model, MMTV-PyMT (PyMT), developed breast tumors with lung metastasis; however, mice deleted in p38δ (PyMT/p38δ^−/−) exhibited delayed primary tumor formation and highly reduced lung metastatic burden. At the cellular level, we demonstrate that targeting of p38δ in breast cancer cells, MCF-7 and MDA-MB-231 resulted in a reduced rate of cell proliferation. Additionally, cells lacking p38δ also displayed an increased cell-matrix adhesion and reduced cell detachment. This effect on cell adhesion was molecularly supported by the regulation of the focal adhesion kinase (FAK) by p38δ in the human breast cell lines. These studies define a previously unappreciated role for p38δ in breast cancer development and evolution by regulating tumor growth and altering metastatic properties.

Shufeng Jiedu Capsule protect against acute lung injury by suppressing the MAPK/NF-κB pathway

This study sought to investigate the protective effect of an alternative medicine, Shufeng Jiedu Capsule, in acute lung injury and inflammation signaling pathways related to that action. Hematoxylin and eosin (HE) staining was used to observe pathological changes in rat lung tissue, arterial blood was subjected to blood gas analysis and lactic acid levels were determined, immunofluorescent staining for interleukin-1β (IL-1β) was performed, enzyme linked immunosorbent assay (ELISA) was used to detect biomarkers of the nuclear factor-κB (NF-κB) inflammation pathway including IL-1β and tumor necrosis factor α (TNF-α), biomarkers of the mitogen-activated protein kinase (MAPK) signal pathway including P-selectin, transforming growth factor β (TGF-β), keratinocyte-derived chemokine (KC), and C-Jun/AP-1 were measured, and real-time PCR was used to detect NF-κB mRNA. Results in rats with lipopolysaccharide-induced acute lung injury suggested that Shufeng Jiedu Capsule may increase the partial pressure of oxygen in lung tissue, decrease lactic acid levels, inhibit inflammatory factors such as IL-1β and TNF-α, and suppress the levels of P-selectin, TGF-β, KC, C-Jun/AP-1, and NF-κB mRNA. Thus, Shufeng Jiedu Capsule is a traditional medicine that may alleviate acute lung injury by suppressing the MAPK/NF-κB signaling pathway.

Establishing a panel of chemo-resistant mesothelioma models for investigating chemo-resistance and identifying new treatments for mesothelioma

Mesothelioma is inherently chemo-resistant with only 50% of patients responding to the standard of care treatments, and consequently it has a very grim prognosis. The aim of this study was to establish a panel of chemo-resistant mesothelioma models with clinically relevant levels of resistance as tools for investigating chemo-resistance and identifying new treatments for mesothelioma. Chemo-resistant cell lines were established in vitro and characterized in vivo using syngeneic Fischer rats. Tumors derived from all chemo-resistant cell lines were immunohistochemically classified as mesothelioma. Homozygous deletion of p16^INK4A/p14^ARF and increased expression of several ATP-binding cassette transporters were demonstrated, consistent with findings in human mesothelioma. Further, the acquisition of chemo-resistance in vitro resulted in changes to tumor morphology and overall survival. In conclusion, these models display many features corresponding with the human disease, and provide the first series of matched parental and chemo-resistant models for in vitro and in vivo mesothelioma studies.

Spontaneous mesotheliomas in F344/N rats are characterized by dysregulation of cellular growth and immune function pathways

Aged male Fischer 344/N rats are prone to developing spontaneous peritoneal mesotheliomas that arise predominantly from the tunica vaginalis of the testes. A definitive cause for the predominance of this neoplasm in F344/N rats is unknown. Investigation of the molecular alterations that occur in spontaneous rat mesotheliomas may provide insight into their pathogenesis as well enable a better understanding regarding the mechanisms underlying chemically induced mesothelioma in rodents. Mesothelial cell function represents a complex interplay of pathways related to host defense mechanisms and maintenance of cellular homeostasis. Global gene expression profiles of spontaneous mesotheliomas from vehicle control male F344/N rats from 2-year National Toxicology Program carcinogenicity bioassays were analyzed to determine the molecular features of these tumors and elucidate tumor-specific gene expression profiles. The resulting gene expression pattern showed that spontaneous mesotheliomas are associated with upregulation of various growth factors, oncogenes, cytokines, pattern recognition response receptors, and pathogen-associated molecular patterns receptors, and the production of reactive oxygen and nitrogen species, as well as downregulation of apoptosis pathways. Alterations in these pathways in turn trigger molecular responses that stimulate cell proliferation and promote tumor survival and progression.