The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway is one of a handful of pleiotropic cascades used to transduce a multitude of signals for development and homeostasis in animals, from humans to flies. In mammals, the JAK/STAT pathway is the principal signaling

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The JAK/STAT signaling pathway

Persistently activated or tyrosine-phosphorylated STAT3 (pSTAT3) is found in 50% of lung adenocarcinomas. pSTAT3 is found in primary adenocarcinomas and cell lines harboring somatic-activating mutations in the tyrosine kinase domain of EGFR. Treatment of cell lines with either an EGFR inhibitor or an src kinase inhibitor had no effect on pSTAT3 levels, whereas a pan-JAK inhibitor (P6) blocked activation of STAT3 and inhibited tumorigenesis. Cell lines expressing these persistently activated mutant EGFRs also produced high IL-6 levels, and blockade of the IL-6/gp130/JAK pathway led to a decrease in pSTAT3 levels. In addition, reduction of IL-6 levels by RNA interference led to a decrease in tumorigenesis. Introduction of persistently activated EGFR into immortalized breast epithelial cells led to tumorigenesis, IL-6 expression, and STAT3 activation, all of which could be inhibited with P6 or gp130 blockade. Furthermore, inhibition of EGFR activity in multiple cell lines partially blocked transcription of IL-6 and concurrently decreased production and release of IL-6. Finally, immunohistochemical analysis revealed a positive correlation between pSTAT3 and IL-6 positivity in primary lung adenocarcinomas. Therefore, mutant EGFR could activate the gp130/JAK/STAT3 pathway by means of IL-6 upregulation in primary human lung adenocarcinomas, making this pathway a potential target for cancer treatment.

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Mutations in the EGFR kinase domain mediate STAT3 activation via IL-6 production in human lung adenocarcinomas

A score based on the combination of the systemic inflammatory response and albumin hazards ratio (HR) 1.70, 95% CI 1.23 - 2.35, P=0.001) was comparable in prognostic value to that based on stage and performance status (HR 1.48, 95% CI 1.12 - 1.95, P=0.006) in patients with inoperable non-small-cell lung cancer. The former is simple to measure and well standardised.

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Evaluation of cumulative prognostic scores based on the systemic inflammatory response in patients with inoperable non-small-cell lung cancer.

Tumours progress through a cascade of events that enable the formation of metastases. Some of the components that are required for this fatal process are well established. Tetraspanins, however, have only recently received attention as both metastasis suppressors and metastasis promoters. This late appreciation is probably due to their capacity to associate with various molecules, which they recruit into special membrane microdomains, and their abundant presence in tumour-derived small vesicles that aid intercellular communication. It is reasonable to assume that differences in the membrane and vesicular web components that associate with individual tetraspanins account for their differing abilities to promote and suppress metastasis.

Tetraspanins: push and pull in suppressing and promoting metastasis

Emerging data from chimeric antigen receptor (CAR) T-cell trials in B-cell malignancies demonstrate that a common mechanism of resistance to this novel class of therapeutics is the emergence of tumors with loss or downregulation of the target antigen. Antigen loss or antigen-low escape is likely to emerge as an even greater barrier to success in solid tumors, which manifest greater heterogeneity in target antigen expression. Potential approaches to overcome this challenge include engineering CAR T cells to achieve multispecificity and to respond to lower levels of target antigen and more efficient induction of natural antitumor immune responses as a result of CAR-induced inflammation. In this article, we review the evidence to date for antigen escape and downregulation and discuss approaches currently under study to overcome these obstacles.Significance: Antigen escape and downregulation have emerged as major issues impacting the durability of CAR T-cell therapy. Here, we explore their incidence and ways to overcome these obstacles in order to improve clinical outcomes. Cancer Discov; 8(10); 1219-26. ©2018 AACR.

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Tumor Antigen Escape from CAR T-cell Therapy.

Serum interleukin 6 (IL-6) levels were measured in 75 patients with lung cancer and in 20 patients with benign lung diseases. IL-6 was detectable in 29 patients with lung cancer (39%), but was not detectable in any of the patients with benign lung diseases. Serum C-reactive protein levels and plasma fibrinogen levels were significantly higher and serum albumin concentration was significantly lower in lung cancer patients with detectable serum IL-6 levels than in those without detectable serum IL-6 levels and in patients with benign lung diseases. On the other hand, no significant difference was observed in blood platelet counts in these three groups. Moreover, serum IL-6 levels were not significantly different in lung cancer patients with or without clinically demonstrated distant metastasis. These results suggest that IL-6 may be a mediator of various reactions including an inflammatory response in lung cancer patients.

Serum levels of interleukin 6 in patients with lung cancer.

Transduction of dendritic cells (DCs) with genes encoding tumor-associated antigen or with other genes that enhance immune reaction has been theorized to be potentially useful for enhancing the efficiency of DC-based immunotherapy. However, gene transduction of DCs generated from human peripheral blood monocytes has been of limited use because of the low efficiency. Here, we report that the efficiency of in vitro adenovirus-mediated gene transduction into human monocyte-derived DCs can be dramatically enhanced by centrifugation. The best conditions for centrifugal gene transduction were determined to be as follows: 2000 x g at 37 degrees C for 2 hr at a multiplicity of infection (MOI) of 10 or greater. By this centrifugal method, approximately 88 and 70% of DCs were gene transducible at an MOI of 50 and 10, respectively. Functional analysis showed that DCs transduced with human interleukin 12 (IL-12)-expressing adenoviral vector under the optimal conditions of centrifugation stably produced IL-12 protein at high levels (8.1 ng/10(6) cells/48 hr). IL-12 gene-modified DCs (DC/IL-12) displayed a more mature phenotype than nontransduced DCs, as judged by decreased expression of CD1a and increased expression of CD83, B7.1 (CD80), B7.2 (CD86), and MHC class I and II molecules. DC/IL-12 showed a high phagocytic ability similar to nontransduced DCs and were significantly superior to control DCs in the stimulation of autologous and allogeneic T lymphocyte responses. The centrifugal transduction method with adenoviral vector might be useful for efficient generation of gene-modified DCs because it is very simple, highly efficient, reproducible, and not cytopathic. IL-12 gene-modified human DCs may be therapeutically useful as a good adjuvant in DC-based immunotherapy.

Enhanced efficiency by centrifugal manipulation of adenovirus-mediated interleukin 12 gene transduction into human monocyte-derived dendritic cells.

Malignant pleural effusion (PE) is a frequent problem in lung cancer. In this study, we established a model of malignant PE of human adenocarcinoma cells, PC-14, in SCID mice. Intravenously injected PC-14 cells formed colonies in the lungs as early as week 4 after tumor inoculation, and produced bloody PE in all recipient SCID mice by week 8. Pretreatment of SCID mice with anti-mouse IL-2 receptor beta chain antibody (TM-beta 1) to deplete natural killer (NK) cells markedly promoted the production of bloody PE and metastases to multiple organs, such as the lungs, liver, kidneys, and lymph nodes 4 weeks after tumor inoculation. Histological studies indicated that PC-14 cells formed colonies in the lungs, and then invaded the pleura and spread to the pleural cavity. To establish cell lines with a high potential to produce PE, we harvested PE, expanded the tumor cells in vitro, and injected them into SCID mice again. By four in vivo selection cycles in this way we obtained PC-14-PM4 cells, which produce lung metastases and PE earlier than PC-14 cells. The survival of SCID mice inoculated with PC-14-PM4 cells was significantly shorter than that of mice inoculated with PC-14 cells. The expressions of adhesion molecules, such as CD44, CD49d, ICAM-1, and MHC class I, on PC-14-PM4 cells tended to increase compared with PC-14 cells. These changes of adhesion molecules seem to be one of possible mechanisms involved in higher metastatic potential of PC-14-PM4 cells. PE models with PC-14 and PC-14-PM4 cells should be useful for biological and preclinical studies on malignant PE produced by human lung cancer.

Model of malignant pleural effusion of human lung adenocarcinoma in SCID mice

KAI1/CD82 has been shown to be a metastasis suppressor for several human cancers, and a recent study revealed that wild-type tumor suppressor p53 can directly activate KAI1/CD82 gene expression. However, the response of KAI1/CD82 expression in cancer cells to exogenous stimulants has not been investigated. The present study examined whether tumor necrosis factor (TNF), which mediates many of the cellular responses associated with inflammatory reactions or cancer progression, can affect the KAI1/CD82 expression in lung cancer cells and, if so, whether nuclear factor (NF)-kappaB, a key molecule in TNF-mediated gene expression, is involved in the mechanism of KAI1/CD82 induction. Our results demonstrated that expression of KAI1/CD82 in PC-14 cells expressing mutant p53 could be augmented by TNF-alpha, and that transfer of the gene for a specific inhibitor of NF-kappaB, IkappaB alphaSR (mutant IkappaB alpha; NF-kappaB super-repressor), into PC-14 cells could inhibit this augmentation. The amount of NF-kappaB in the nucleus of PC-14/IkappaB alphaSR cells correlated well with KAI1/CD82 mRNA and protein expression. In addition, IkappaB alphaSR gene transfer inhibited the spontaneous expression of KAI1/CD82 protein in KAI1/CD82-high-expressing RERF-LC-OK cells, which contain a mutant-type p53. These observations indicate that NF-kappaB activation may play a role in the regulation of KAI1/CD82 expression in lung cancer cells independently of wild-type p53, and suggest that KAI1/CD82 expression may be regulated by interaction with the host microenvironment.

https://cancerres.aacrjournals.org/content/canres/61/2/673.full.pdf

Tsutomu Shinohara

Papers

Serum levels of interleukin 6 in patients with lung cancer.

Enhanced efficiency by centrifugal manipulation of adenovirus-mediated interleukin 12 gene transduction into human monocyte-derived dendritic cells.

Model of malignant pleural effusion of human lung adenocarcinoma in SCID mice

Nuclear factor-kappaB-dependent expression of metastasis suppressor KAI1/CD82 gene in lung cancer cell lines expressing mutant p53.

Goodpasture's disease in a patient with advanced lung cancer treated with nivolumab: An autopsy case report.