Biological prognostic factors in non-small cell lung cancer

An individual-based model for collective cancer cell migration explains speed dynamics and phenotype variability in response to growth factors

Collective cell migration is a common phenotype in epithelial cancers, which is associated with tumor cell metastasis and poor patient survival. However, the interplay between physiologically relevant pro-migratory stimuli and the underlying mechanical cell–cell interactions are poorly understood. We investigated the migratory behavior of different collectively migrating non-small cell lung cancer cell lines in response to motogenic growth factors (e.g. epidermal growth factor) or clinically relevant small compound inhibitors. Depending on the treatment, we observed distinct behaviors in a classical lateral migration assay involving traveling fronts, finger-shapes or the development of cellular bridges. Particle image velocimetry analysis revealed characteristic speed dynamics (evolution of the average speed of all cells in a frame) in all experiments exhibiting initial acceleration and subsequent deceleration of the cell populations. To better understand the mechanical properties of individual cells leading to the observed speed dynamics and the phenotypic differences we developed a mathematical model based on a Langevin approach. This model describes intercellular forces, random motility, and stimulation of active migration by mechanical interaction between cells. Simulations show that the model is able to reproduce the characteristic spatio-temporal speed distributions as well as most migratory phenotypes of the studied cell lines. A specific strength of the proposed model is that it identifies a small set of mechanical features necessary to explain all phenotypic and dynamical features of the migratory response of non-small cell lung cancer cells to chemical stimulation/inhibition. Furthermore, all processes included in the model can be associated with potential molecular components, and are therefore amenable to experimental validation. Thus, the presented mathematical model may help to predict which mechanical aspects involved in non-small cell lung cancer cell migration are affected by the respective therapeutic treatment.

In many cancers, spreading and the formation of metastasis involve the coordinated migration of many cells. An interdisciplinary team of researchers from Heidelberg and Frankfurt studied the collective movement of cultured lung cancer cells subject to chemical stimulation. Based on extensive data analysis a mathematical model was developed to explain the variety of migration behaviors observed under different treatments. The model describes the mechanics of compression, stretch, cell elasticity and force-regulated active motion—which in sum lead to coordination within large cell groups. Simulations demonstrate how these mechanical features affect cell coordination and collective behavior. In tests of potential medical treatment strategies, the model can be used to predict the effects of the drug on specific mechanical properties of single cells.

A front-line window of opportunity phase 2 study of sorafenib in patients with advanced nonsmall cell lung cancer: North Central Cancer Treatment Group Study N0326

BACKGROUND

The current study was conducted to assess the efficacy and toxicity of sorafenib as front-line therapy in patients with stage IIIB (pleural effusion) or IV nonsmall cell lung cancer (NSCLC).

METHODS

Patients received sorafenib 400 mg twice daily by mouth continuously, and were evaluated every 2 weeks during the first 8 weeks. Patients who manifested clinical progression during this period proceeded to receive standard of care. The primary endpoint was confirmed objective tumor response. A 2-stage Fleming design was used such that if at most 1 confirmed partial response (PR) or complete response was observed in the first 20 patients (stage 1), the treatment would be considered ineffective, and further enrollment would be discontinued.

RESULTS

Only 1 PR was observed in the first 20 patients. By the time of study closure, 5 additional patients who were already being screened for study inclusion were enrolled. Of the 25 patients (15 women, 10 men; 4 stage IIIB, 21 stage IV; median age, 67 years [range, 45-85 years]), there were 3 (12%) PRs and 6 (24%) cases with stable disease observed. The median time-to-progression and progression-free survival was 2.8 months. Seven (28%) patients remained progression-free at 24 weeks. No grade 3 or higher hematologic adverse events were observed. Thirteen (52%) patients had a grade 3 nonhematologic adverse event, with fatigue (20%), diarrhea (8%), and dyspnea (8%) being the most common.

CONCLUSIONS

Sorafenib is not effective as front-line therapy in the general unselected NSCLC population. The window of opportunity design is feasible for estimating the activity of novel compounds.

Phase I Trial of Sorafenib in Combination with Gefitinib in Patients with Refractory or Recurrent Non–Small Cell Lung Cancer

PURPOSE

To evaluate the combination of sorafenib and gefitinib in patients with advanced non-small cell lung cancer.

EXPERIMENTAL DESIGN

In this dose-escalation trial, patients received oral sorafenib (200-400 mg) twice daily with gefitinib (250 mg orally) once daily to identify the recommended dose for phase II trials (RDP; part A). The pharmacokinetics of the RDP were characterized further in additional patients (part B) receiving single-agent gefitinib or sorafenib for 21 days followed by a 7-day washout with crossover to the other agent for an additional 21 days. Patients then received the combination of sorafenib plus gefitinib in 28-day cycles. Safety, pharmacokinetics, and antitumor efficacy were evaluated. Potential drug-drug interactions and the relationship between pharmacokinetics and toxicity were also assessed.

RESULTS

Thirty-one patients were treated (n=12, part A; n=19, part B). Most adverse events were grade 1/2. The most frequent grade 3/4 events included diarrhea and elevated alanine aminotransferase (both 9.7%). One dose-limiting toxicity occurred (part A: elevated alanine aminotransferase at 400 mg twice daily). Gefitinib had no effect on sorafenib pharmacokinetics. However, gefitinib C(max) (26%) and area under the curve (38%) were reduced by concomitant sorafenib. One patient had a partial response; 20 (65%; n=8, part A; n=12, part B) had stable disease >or=4 months. The RDP was sorafenib 400 mg twice daily with gefitinib 250 mg once daily.

CONCLUSIONS

Sorafenib combined with gefitinib is well tolerated, with promising efficacy in patients with advanced non-small cell lung cancer. Studies to further investigate the significance of the reduction in gefitinib exposure by sorafenib are warranted.

A paracrine loop between tumor cells and macrophages is required for tumor cell migration in mammary tumors

Invasion of tumor cells into the surrounding connective tissue and blood vessels is a key step in the metastatic spread of breast tumors. Although the presence of macrophages in primary tumors is associated with increased metastatic potential, the mechanistic basis for this observation is unknown. Using a chemotaxis-based in vivo invasion assay and multiphoton-based intravital imaging, we show that the interaction between macrophages and tumor cells facilitates the migration of carcinoma cells in the primary tumor. Gradients of either epidermal growth factor (EGF) or colony-stimulating factor 1 (CSF-1) stimulate collection into microneedles of tumor cells and macrophages even though tumor cells express only EGF receptor and macrophages express only CSF-1 receptor. Intravital imaging shows that macrophages and tumor cells migrate toward microneedles containing either EGF or CSF-1. Inhibition of either CSF-1- or EGF-stimulated signaling reduces the migration of both cell types. This work provides the first direct evidence for a synergistic interaction between macrophages and tumor cells during cell migration in vivo and indicates a mechanism for how macrophages may contribute to metastasis.