Figure 2: TMPs are critical for conserving primary tumour characteristics in explants.

(a) The average composition and abundance range of key components of TMP. Abundance range was measured based on area under the peak using Pearson’s correlation for clustering of protein features. The line within each notch box represents the median, and the lower and upper boundaries of the box indicate first and third quartiles, respectively (n=24), of some of the key TMPs isolated from (b) HNSCC (n=12) and (c) CRC tumours (n=12) (d) scanning electron microscopy (SEM) images of plastic surface precoated with Collagen-I (top) or TMP cocktails (bottom). Scale bars, 1 μm. Adherence of the component proteins to the surface and their ability to form networks is shown following immunofluorescence (IF) staining using human Collagen-I antibody. Adherence was measured by detecting specific fluorescence signal in coated area contrasting to uncoated area of the same surface. Scale bars, 200 μm (right). (e) HNSCC explants were cultured for 72 h in plates coated with different concentrations of TMP as indicated. Maintenance of overall intratumoral heterogeneity and integrity was determined by hematoxylin and eosin staining (H&E; top) and tumour cell proliferation by Ki-67 staining (bottom). Scale bar, 100 μm. (f) Tumours from HNSCC patients were sliced. Explants were cultured for 72 h in plates coated with different concentrations of TMP as indicated. Percent tumour area, cell viability and Ki-67+ cells per field was measured (mean±s.d.). *P≤0.05 compared with uncoated control using paired t-test. Data represent one of the five independent experiments performed in triplicates. (g) HNSCC tumour slices cultured for 72 h with or without TMP were subjected to extraction of native extracellular matrix (ECM). Preservation of ECM 72 h post culture was determined by IF staining of extracted ECM parallel to SEM imaging (inset). (h) HNSCC tumours of high and low grades were sectioned cultured for 72 h in plates coated with matched and unmatched TMP (high and low grade) Scatter plot indicates the effects of grade-matched and unmatched TMP on retaining the proliferation profile. Percent Ki–67–positive cells from HNSCC explants were calculated at the end of 72 h based on T₀ score. **P<0.0002, ^#P<0.05 for the high-grade tumours cultured in presence of low-grade TMP by paired Student’s t-test. NS, not significant (n=12). (i) Representative images show the effects of CRC-specific TMP and other coating materials on pERK status (top), proliferation (middle) and morphology (bottom) of tumour explants. Scale bar, 100 μm. (j) Quantitative analysis of TMP on proliferation, tumour area and pERK status in CRC explants. **P <0.01 compared with T72 control (analysis of variance, n=8).