RNA-Seq of single prostate CTCs implicates noncanonical Wnt signaling in antiandrogen resistance
David T Miyamoto1, Yu Zheng2, Ben S Wittner3
1Massachusetts General Cancer Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA. Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
Abstract:
Prostate cancer is initially responsive to androgen deprivation, but the effectiveness of androgen receptor (AR) inhibitors in recurrent disease is variable. Biopsy of bone metastases is challenging; hence, sampling circulating tumor cells (CTCs) may reveal drug-resistance mechanisms. We established single-cell RNA-sequencing (RNA-Seq) profiles of 77 intact CTCs isolated from 13 patients (mean six CTCs per patient), by using microfluidic enrichment. Single CTCs from each individual display considerable heterogeneity, including expression of AR gene mutations and splicing variants. Retrospective analysis of CTCs from patients progressing under treatment with an AR inhibitor, compared with untreated cases, indicates activation of noncanonical Wnt signaling (P = 0.0064). Ectopic expression of Wnt5a in prostate cancer cells attenuates the antiproliferative effect of AR inhibition, whereas its suppression in drug-resistant cells restores partial sensitivity, a correlation also evident in an established mouse model. Thus, single-cell analysis of prostate CTCs reveals heterogeneity in signaling pathways that could contribute to treatment failure.
Insights
Single-cell analysis of circulating tumor cells (CTCs) in prostate cancer patients reveals significant heterogeneity. This heterogeneity, including noncanonical Wnt signaling activation, may explain variable responses to androgen receptor (AR) inhibitors and treatment failure.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Prostate cancer initially responds to androgen deprivation therapy (ADT).
- Recurrent prostate cancer often develops resistance to androgen receptor (AR) inhibitors.
- Analyzing circulating tumor cells (CTCs) offers a less invasive method to study drug resistance mechanisms compared to bone metastasis biopsy.
Purpose of the Study:
- To investigate the heterogeneity of circulating tumor cells (CTCs) in prostate cancer patients.
- To identify potential mechanisms of resistance to androgen receptor (AR) inhibitors.
- To explore the role of signaling pathways in treatment failure.
Main Methods:
- Isolation and enrichment of intact CTCs using microfluidics.
- Single-cell RNA-sequencing (RNA-Seq) profiling of 77 CTCs from 13 patients.
- Retrospective analysis comparing CTCs from treated and untreated patients.
Main Results:
- Significant heterogeneity observed in single CTCs, including AR gene mutations and splicing variants.
- Activation of noncanonical Wnt signaling identified in CTCs from patients progressing on AR inhibitors (P = 0.0064).
- Wnt5a overexpression reduced sensitivity to AR inhibition; Wnt5a suppression restored partial sensitivity in resistant cells, confirmed in a mouse model.
Conclusions:
- Single-cell analysis of prostate CTCs reveals substantial heterogeneity in signaling pathways.
- Aberrant Wnt signaling may contribute to treatment failure in advanced prostate cancer.
- Understanding CTC heterogeneity is crucial for developing effective therapeutic strategies against resistant prostate cancer.
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