'Cloudbuster': a Python-based open source application for three-dimensional reconstruction and quantification of stacked biological imaging samples

Three-dimensional (3D) spheroid cultures are generating increasing interest in cancer research, e.g. for the evaluation of pharmacological effects of novel small molecule inhibitors. This is mainly due to the fact that such 3D structures reflect physiological characteristics of tumours and the cellular microenvironments they reside in more faithfully than two-dimensional (2D) cell cultures; in addition, they allow the reduction of animal experiments while providing significantly relevant human-based models. Quantification of such organoid structures as well as the mainly slice-based acquisition and thus forced 2D representation of 3D spheroids provide a challenge for the interpretation of the associated generated data. Here, we provide a novel open-source workflow to reconstruct a 3D entity from slice-recorded microscopical images with or without treatment with anti-migratory small molecule inhibitors. This reconstruction produces distinct point clouds as basis for subsequent comparison of basic readout parameters using average computer processor, memory and graphics resources within an acceptable time frame. We were able to validate the usefulness of this workflow using 3D data generated by various imaging techniques, including z-stacks from confocal microscopy and histochemically labelled spheroid sectioning, and demonstrate the possibility to accurately characterize inhibitor effects in great detail.

Cell migration in paediatric glioma; characterisation and potential therapeutic targeting

BACKGROUND

Paediatric high grade glioma (pHGG) and diffuse intrinsic pontine glioma (DIPG) are highly aggressive brain tumours. Their invasive phenotype contributes to their limited therapeutic response, and novel treatments that block brain tumour invasion are needed.

METHODS

Here, we examine the migratory characteristics and treatment effect of small molecule glycogen synthase kinase-3 inhibitors, lithium chloride (LiCl) and the indirubin derivative 6-bromoindirubin-oxime (BIO), previously shown to inhibit the migration of adult glioma cells, on two pHGG cell lines (SF188 and KNS42) and one patient-derived DIPG line (HSJD-DIPG-007) using 2D (transwell membrane, immunofluorescence, live cell imaging) and 3D (migration on nanofibre plates and spheroid invasion in collagen) assays.

RESULTS

All lines were migratory, but there were differences in morphology and migration rates. Both LiCl and BIO reduced migration and instigated cytoskeletal rearrangement of stress fibres and focal adhesions when viewed by immunofluorescence. In the presence of drugs, loss of polarity and differences in cellular movement were observed by live cell imaging.

CONCLUSIONS

Ours is the first study to demonstrate that it is possible to pharmacologically target migration of paediatric glioma in vitro using LiCl and BIO, and we conclude that these agents and their derivatives warrant further preclinical investigation as potential anti-migratory therapeutics for these devastating tumours.

ASPM and microcephalin expression in epithelial ovarian cancer correlates with tumour grade and survival

BACKGROUND

The clinico-pathological and molecular heterogeneity of epithelial ovarian cancer (EOC) complicates its early diagnosis and successful treatment. Highly aneuploid tumours and the presence of ascitic fluids are hallmarks of EOC. Two microcephaly-associated proteins, abnormal spindle-like microcephaly-associated protein (ASPM) and microcephalin, are involved in mitosis and DNA damage repair. Their expression is deregulated at the RNA level in EOC. Here, ASPM and microcephalin protein expression in primary cultures established from the ascites of patients with EOC was determined and correlated with clinical data to assess their suitability as biomarkers.

METHODS

Five established ovarian cancer cell lines, cells derived from two benign ovarian ascites samples and 40 primary cultures of EOC derived from ovarian ascites samples were analysed by protein slot blotting and/or immunofluorescence to determine ASPM and microcephalin protein levels and their cellular localisation. Results were correlated with clinico-pathological data.

RESULTS

A statistically significant correlation was identified for ASPM localisation and tumour grade, with high levels of cytoplasmic ASPM correlating with grade 1 tumours. Conversely, cytoplasmic microcephalin was only identified in high-grade tumours. Furthermore, low levels of nuclear microcephalin correlated with reduced patient survival.

CONCLUSION

Our results suggest that ASPM and microcephalin have the potential to be biomarkers in ovarian cancer.