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Phosphoproteomics scaled-down to tumor biopsy level -part 1 cell line

ABSTRACT: Mass spectrometry-based phosphoproteomics of tumor tissue or cell line lysates provides insight in aberrantly activated signaling pathways and potential drug targets. For improved understanding of the individual patient’s tumor biology, analysis of the phosphoproteome should be feasible and reproducible using tumor needle biopsies. We hereto scaled down a pTyr-phosphopeptide enrichment protocol to biopsy-level protein input and show its performance using colorectal cancer (CRC) cell line and needle biopsies from patients. In this study, the feasibility of label-free pTyr-phosphoproteomics at the biopsy level is demonstrated. Unsupervised cluster analysis shows that this approach can identify patient-specific profiles, which will improve our understanding of individual tumor biology and may enable future pTyr-phosphoproteomics-based TKI treatment selection.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell

DISEASE(S): Colon Cancer

SUBMITTER: Sander Piersma

LAB HEAD: Connie Ramona Jimenez

PROVIDER: PXD003808 | Pride | 2022-03-02

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	MxQ_1mg.zip	Other
	MxQ_all.zip	Other
	QE2_131113_OPL0000_pTyr_IP_A_02.raw	Raw
	QE2_131113_OPL0000_pTyr_IP_B_03.raw	Raw
	QE2_131113_OPL0000_pTyr_IP_C_04.raw	Raw

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Project description:The purpose of this study was to identify molecular markers of pathologic response to neoadjuvant paclitaxel/radiation treatment, protein and gene expression profiling were done on pretreatment biopsies. Patients with high-risk, operable breast cancer were treated with three cycles of paclitaxel followed by concurrent paclitaxel/radiation. Tumor tissue from pretreatment biopsies was obtained from 19 of the 38 patients enrolled in the study. Protein and gene expression profiling were done on serial sections of the biopsies from patients that achieved a pathologic complete response (pCR) and compared to those with residual disease, non-pCR (NR). Proteomic and validation immunohistochemical analyses revealed that Î±-defensins (DEFA) were overexpressed in tumors from patients with a pCR. Gene expression analysis revealed that MAP2, a microtubule-associated protein, had significantly higher levels of expression in patients achieving a pCR. Elevation of MAP2 in breast cancer cell lines led to increased paclitaxel sensitivity. Furthermore, expression of genes that are associated with the basal-like, triple-negative phenotype were enriched in tumors from patients with a pCR. Analysis of a larger panel of tumors from patients receiving presurgical taxane-based treatment showed that DEFA and MAP2 expression as well as histologic features of inflammation were all statistically associated with response to therapy at the time of surgery. We show the utility of molecular profiling of pretreatment biopsies to discover markers of response. Our results suggest the potential use of immune signaling molecules such as DEFA as well as MAP2, a microtubule-associated protein, as tumor markers that associate with response to neoadjuvant taxaneâbased therapy. Tumor tissues from pretreatment needle biopsies from patients enrolled on a paclitaxel/radiation clinical trial were laser capture microdissected for RNA extraction and hybridization to Affymetrix microarrays. We analyzed one array (sample A) from duplicate samples from each patient. 14 subject, 2 replicates each.

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Phosphoproteomics scaled-down to tumor biopsy level -part 1 cell line

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