Subtypes of pancreatic stellate cells and distant metastasis of pancreatic ductal adenocarcinoma

Cytokines chattering in pancreatic ductal adenocarcinoma tumor microenvironment

Pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME) consists of multiple cell types interspersed by dense fibrous stroma. These cells communicate through low molecular weight signaling molecules called cytokines. The cytokines, through their receptors, facilitate PDAC initiation, progression, metastasis, and distant colonization of malignant cells. These signaling mediators secreted from tumor-associated macrophages, and cancer-associated fibroblasts in conjunction with oncogenic Kras mutation initiate acinar to ductal metaplasia (ADM), resulting in the appearance of early preneoplastic lesions. Further, M1- and M2-polarized macrophages provide proinflammatory conditions and promote deposition of extracellular matrix, whereas myofibroblasts and T-lymphocytes, such as Th17 and T-regulatory cells, create a fibroinflammatory and immunosuppressive environment with a significantly reduced cytotoxic T-cell population. During PDAC progression, cytokines regulate the expression of various oncogenic regulators such as NFκB, c-myc, growth factor receptors, and mucins resulting in the formation of high-grade PanIN lesions, epithelial to mesenchymal transition, invasion, and extravasation of malignant cells, and metastasis. During metastasis, PDAC cells colonize at the premetastatic niche created in the liver, and lung, an organotropic function primarily executed by cytokines in circulation or loaded in the exosomes from the primary tumor cells. The indispensable contribution of these cytokines at every stage of PDAC tumorigenesis makes them exciting candidates in combination with immune-, chemo- and targeted radiation therapy.

Metastatic patterns and prognosis of young lung cancer patients: a population-based study by age

Background

We aimed to examine the different metastatic patterns and corresponding survival outcomes between all ages of young (aged <60 years) and elderly lung cancer patients.

Methods

Lung cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2015 were divided into a young and elderly group. The young group was subdivided into four consecutive subgroups. Baseline characteristics were analyzed by the Chi-square test. Survival differences were evaluated by Kaplan-Meier curves and Cox proportional hazards models.

Results

Of the total 200,362 lung cancer patients, 155,348 were elderly patients and 45,014 were young patients, including 3,461 aged <45 years, 5,697 aged 45–49 years, 13,645 aged 50–54 years, and 22,211 aged 55–59 years. Compared with elderly lung cancer patients, extrathoracic metastases were significantly more frequent in each younger group, irrespective of the site and number of extrathoracic metastatic organs. Regardless of metastasis patterns, young ages were independent prognostic factors of lung cancer-specific survival (LCSS) [<45 years: hazard ratio (HR): 0.70; 45–49 years: HR: 0.87; 50–54 years: HR: 0.90; 55–59 years: HR: 0.93, all P values were <0.001]. In each age subgroup, patients with multi-organ extrathoracic metastasis had the worst LCSS.

Conclusions

Young lung cancer patients across all ages were at increased risk of extrathoracic metastasis, especially multi-organ patterns, but had a reduced risk of lung cancer-related death compared to elderly patients. Regular and meticulous monitoring of potential metastasized organs is required in young lung cancer patients throughout the follow-up period.

Interfacial Curvature in Confined Coculture Directs Stromal Cell Activity with Spatial Corralling of Pancreatic Cancer Cells

Interfacial cues in the tumor microenvironment direct the activity and assembly of multiple cell types. Pancreatic cancer, along with breast and prostate cancers, is enriched with cancer-associated fibroblasts (CAFs) that activate to coordinate the deposition of the extracellular matrix, which can comprise over 90% of the tumor mass. While it is clear that matrix underlies the severity of the disease, the relationship between stromal-tumor cell assembly and cell-matrix dynamics remains elusive. Micropatterned hydrogels deconstruct the interplay between matrix stiffness and geometric confinement, guiding heterotypic cell populations and matrix assembly in pancreatic cancer. Interfacial cues at the perimeter of microislands guide CAF migration and direct cancer cell assembly. Computational modeling shows curvature-stress dependent cellular localization for cancer and CAFs in coculture. Regions of convex curvature enhance edge stress that activates a myofibroblast phenotype in the CAFs with migration and increased collagen I deposition, ultimately leading to a central "corralling" of cancer cells. Inhibiting mechanotransduction pathways decreases CAF activation and the associated corralling phenotype. Together, this work reveals how interfacial biophysical cues underpin aspects of stromal desmoplasia, a hallmark of disease severity and chemoresistance in the pancreatic, breast, and prostate cancers, thereby providing a tool to expand stroma-targeting therapeutic strategies.