Primary culture of squamous head and neck cancer with and without 3T3 fibroblasts and effect of clinical tumor characteristics on growth in vitro

Engineering stromal heterogeneity in cancer

Based on our exponentially increasing knowledge of stromal heterogeneity from advances in single-cell technologies, the notion that stromal cell types exist as a spectrum of unique subpopulations that have specific functions and spatial distributions in the tumor microenvironment has significant impact on tumor modeling for drug development and personalized drug testing. In this Review, we discuss the importance of incorporating stromal heterogeneity and tumor architecture, and propose an overall approach to guide the reconstruction of stromal heterogeneity in vitro for tumor modeling. These next-generation tumor models may support the development of more precise drugs targeting specific stromal cell subpopulations, as well as enable improved recapitulation of patient tumors in vitro for personalized drug testing.

Synthesis and characterization of ester-diol based polyurethane: a potentiality check for hypopharyngeal tissue engineering application

Abstract

Hypopharyngeal tissue engineering is increasing rapidly in this developing world. Tissue damage or loss needs the replacement by another biological or synthesized membrane using tissue engineering. Tissue engineering research is emerging to provide an effective solution for damaged tissue replacement. Polyurethane in tissue engineering has successfully been used to repair and restore the function of damaged tissues. In this context, Can polyurethane be a useful material to deal with hypopharyngeal tissue defects? To explore this, here ester diol based polyurethane (PU) was synthesized in two steps: firstly, polyethylene glycol 400 (PEG 400) was reacted with lactic acid to prepare ester diol, and then it was polymerized with hexamethylene diisocyanate. The physical, mechanical, and biological testing was done to testify the characterization of the membrane. The morphology of the synthesized membrane was investigated by using field emission scanning electron microscopy. Functional groups of the obtained membrane were characterized by fourier transform infrared spectroscopy spectroscopy. Several tests were performed to check the in vitro and in vivo biocompatibility of the membrane. A highly connected homogeneous network was obtained due to the appropriate orientation of a hard segment and soft segment in the synthesized membrane. Mechanical property analysis indicates the membrane has a strength of 5.15 MPa and strain 124%. The membrane showed high hemocompatibility, no cytotoxicity on peripheral blood mononuclear cell, and susceptible to degradation in simulated body fluid solution. Antimicrobial activity assessment has shown promising results against clinically significant bacteria. Primary hypopharyngeal cell growth on the PU membrane revealed the cytocompatibility and subcutaneous implantation on the back of Wistar rats were given in vivo biocompatibility of the membrane. Therefore, the synthesized material can be considered as a potential candidate for a hypopharyngeal tissue engineering application.

Graphic abstract

Efficient and simple approach to in vitro culture of primary epithelial cancer cells

Primary breast and prostate epithelial cancer cells may be efficiently cultured in vitro using simple and easily validatable approach–plates coated with a mixture of extracellular matrix components and tissue-specific primary cell medium.

Primary cancer cells constitute a favourable testing platform for in vitro research in oncology field as they reflect tumour state more accurately than the most commonly employed stable cell lines. Unfortunately, due to limited availability of material and difficulties with protocols validation, primary models are rarely implemented into laboratory practice.

We have compared protocols for primary cultures, differing in media components and plate coatings. In terms of culture establishment, application of Geltrex® coating demonstrated equal efficiency to feeder layer (83% compared with 72% successfully established breast and 80% compared with 80% prostate tumour specimens), yet it was substantially less complicated and easier to validate. Both Geltrex® coating and tissue-specific primary cell medium were permanently required to successfully maintain primary epithelial prostate cancer cells (PEPCs) in culture. In case of primary epithelial breast cancer cells (PEBCs), collagen I coating enabled to obtain comparable number of passages to Geltrex® coating (P=0.438). Commercial primary cell media demonstrated lower efficiency than tissue-specific ones (PEPCs–5 compared with 8 and PEBCs–6 compared with 9 passages). Interestingly, both analysed tumour types were unsusceptible to induction of culture lifespan extension when transduced with SV40LT, BMI-1 or hEST2 genes, commonly applied as potential immortalizing agents.

In conclusion, the approach based on extracellular matrix reconstitution and tissue-specific primary cell media is easy to validate and provides in vitro expansion sufficient for analytical purposes (approximately 8 passages). Therefore, it may facilitate implementation of hardly available experimental models for a variety of analyses.

Feeder layers: co-culture with nonneoplastic cells

Maintenance of a mitotically inactive feeder layer which is able to provide extracellular matrix and growth factors can be critical in establishing and maintaining primary tumor cells. How feeder cells are handled and processed is crucial for providing trouble-free support for primary tumor cells and spontaneously immortalized lines.

Determination of radiosensitivity in established and primary squamous cell carcinoma cultures using the micronucleus assay

In this study, the cytokinesis-block micronucleus assay (CBMN) was used to measure radiosensitivity in three established cell lines (SCC-61, V175 and V134) and 10 primary cell cultures of squamous cell carcinoma (SCC) of the head and neck. Assessment involved optimisation of the assay to determine cytochalasin-B (CB) concentration and sampling time postirradiation. A much closer correlation between dose-response data measured in the clonogenic and micronucleus assays was found when the micronucleus assay was performed under standardised conditions for each cell line (2 micrograms/ml CB: 48 h postirradiation) instead of predetermined optimised assay conditions. This indicates that, for these SCC cell lines, the CBMN assay may be able to predict in vitro radiosensitivity. To be of clinical use in predicting radiosensitivity, the CBMN assay also needs to be evaluated with primary cell cultures. In this study, no relationship between micronucleus frequency at 2 or 6 Gy and patient clinical outcome 12 months following surgery and radiotherapy was seen. Similarly, no association between patient outcome and tumour stage, nodal stage and histology was observed. These CBMN assay data from the primary cell cultures are presently inconclusive as a measure of patient tumour radiosensitivity.

Lack of association between in vitro clonogenic growth of human cervical carcinoma and tumour stage, differentiation, patient age, host cell infiltration or patient survival

Biopsies from 117 patients with cervical carcinoma were studied using a clonogenic assay to assess in vitro growth. Successful colony growth was achieved in 84 tumours (72%) with a mean colony-forming efficiency (CFE), based on total viable nucleated cell counts, of 0.18 +/- 0.49% (+/- 1 standard deviation). There was a wide range of values, from 0.003-4.28%, with a coefficient of variation of 272%. The relationship between clinical features of cervical carcinoma and in vitro colony formation was investigated. No significant association was demonstrated between in vitro growth and either clinical stage (r = 0.02), tumour differentiation (r = -0.08) or patient age (r = -0.12). There was no significant difference in tumour grade between the group of tumours which failed to grow in culture and those which grew well (p = 0.70). In addition, there was no correlation between CFE and the degree of macrophage (r = 0.001), lymphocyte (r = 0.12), or granulocyte (r = 0.08) infiltration. There was no significant difference between CFEs of tumours from patients who had died and from those who were alive and well after a minimum of 2 years' follow-up after radiotherapy (p = 0.51). Ability to form colonies in agar was not associated with a worse prognosis (p = 0.49). Although CFE is an independent biological parameter, our results suggest that, for cervical carcinoma, it is not useful as a univariate prognostic factor.

Differentiation of the human pancreatic adenocarcinoma cell line (Capan-1) in culture and co-culture with fibroblasts dome formation

This study was designed to investigate differentiation of human pancreatic duct carcinoma cells (Capan-1) in vitro. Observations on live cells, and electron microscopic examination, together with enzymological and immunocytochemical methods, have demonstrated that these cells differentiate spontaneously at an early stage. The cells are seen to be joined by apical junctions. High ATPase activity can be detected in the basolateral membranes, and the cells secrete a gastric type mucin (MI) bearing acidic groups. During differentiation in culture, they form domes which are thought to be the morphological expression of trans-epithelial transport of water and electrolytes. This particular structure is transitory, since after 6 days in culture all the cells lose their adhesivity, and form into floating cords. Co-culture of Capan-1 cells and human, nude mice or chick embryo fibroblasts leads to a higher degree of differentiation of epithelial cells, reflected by the earlier appearance of numerous domes. In addition, the anchorage of Capan-1 cells to fibroblasts prevents retraction of the monolayer, and enables the domes to be maintained in the cultures for more than one month. These findings suggest that Capan-1 cells are able to carry out trans-epithelial movement of water and electrolytes. It is suggested that excretion of ions (bicarbonate and/or chloride) is preserved after transformation of pancreatic duct cells. Mucins (MI) and the recently described VIP receptor sites are also thought to play a part in these exchange processes.