Expression of Proteolytic Enzymes by Small Cell Lung Cancer Circulating Tumor Cell Lines

Abstract

Small cell lung cancer (SCLC) is an aggressive type of lung cancer which disseminates vigorously and has a dismal prognosis. Metastasis of SCLC is linked to an extremely high number of circulating tumor cells (CTCs), which form chemoresistant spheroids, termed tumorospheres. Intravasation and extravasation during tumor spread requires the activity of a number of proteases to disintegrate the stroma and vascular tissue. Generation of several permanent SCLC CTC lines allowed us to screen for the expression of 35 proteases using Western blot arrays. Cell culture supernatants of two CTC lines, namely BHGc7 and 10, were analyzed for secreted proteases, including matrix metalloproteinases (MMPs), ADAM/TS, cathepsins, kallikreins, and others, and compared to proteases expressed by SCLC cell lines (GLC14, GLC16, NCI-H526 and SCLC26A). In contrast to NCI-H526 and SCLC26A, MMP-9 was highly expressed in the two CTC lines and in GLC16 derived of a relapse. Furthermore, cathepsins (S, V, X/Z/P, A and D) were highly expressed in the CTC lines, whereas ADAM/TS and kallikreins were not detectable. In conclusion, SCLC CTCs express MMP-9 and a range of cathepsins for proteolysis and, aside from tissue degradation, these enzymes are involved in cell signaling, survival, and the chemoresistance of tumor cells.

Directionality of Macrophages Movement in Tumour Invasion: A Multiscale Moving-Boundary Approach

“… 2013 ; Newby 2008 ; Rath et al. 2019 ) thus helping tumour invasion. We considered this modelling and computational approach since in the experimental literature there is still little knowledge about the directional interactions of macrophages with the directional/random ECM architecture, and how this affects tumour spread.…”

Cathepsin S: investigating an old player in lung disease pathogenesis, comorbidities, and potential therapeutics

“…CTSS proteolytic degradation of nidogen-1, an essential component of the basement membrane and a substrate of CTSS, is strongly associated with non-small cell lung cancer [131]. A recent study showed an increased and exclusive secretion of CTSS in circulating tumor cells of small cell lung cancer, which may predict distant metastasis and targeting CTSS may limit tumor dissemination to distal sites [132]. Interestingly, CTSS has also been linked to breast-to-brain metastasis via processing of the junctional adhesion molecule-B and subsequent blood-brain barrier transmigration [75].…”

Liquid Biopsy-Based Biomarkers of Treatment Response and Resistance

“…Several groups have demonstrated that CTCs can be cultured, notably from breast and prostate cancer patients (e.g., Zhang et al, 2013;Yu et al, 2014;Kolostova et al, 2014), with potential for real-time drug testing to predict donor patient responses with robust assays tailored to low cell numbers (Figure 1). CTC cell lines can also be derived, notably from patients with breast, colorectal, and gastric cancers, and with SCLC (Yu et al, 2014;Rath et al, 2019, Brungs et al, 2020Soler et al, 2018;Klameth et al, 2017) adding new tools for drug development and to explore the biology of advanced cancers, with the caveat, as with all cell cul-tures, that long-term passage on plastic is likely to result in irreversible adaptation and clonal outgrowth. CTCs have also been used to generate patient CTC Derived eXplant (CDX) models in mice, first shown for CTCs in breast cancer patients (Baccelli et al, 2013) and subsequently in SCLC where CDX models reproduce the donor patient's response to standard-of-care chemotherapy (Hodgkinson et al, 2014;Drapkin et al, 2018, Figure 1).…”