Qing Cheng

BACKGROUND: Hormonal therapy targeting the androgen receptor inhibits prostate cancer (PCa), but the tumor eventually recurs as castration-resistant prostate cancer (CRPC). OBJECTIVE: To understand the mechanisms by which subclones within early PCa develop into CRPC. DESIGN, SETTING, AND PARTICIPANTS: We isolated epithelial cells from fresh human PCa cases, including primary adenocarcinoma, locally recurrent CRPC, and metastatic CRPC, and utilized single-cell RNA sequencing to identify subpopulations destined to become either CRPC-adeno or small cell neuroendocrine carcinoma (SCNC). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We revealed dynamic transcriptional reprogramming that promotes disease progression among 23226 epithelial cells using single-cell RNA sequencing, and validated subset-specific progression using immunohistochemistry and large cohorts of publically available genomic data. RESULTS AND LIMITATIONS: We identified a small fraction of highly plastic CRPC-like cells in hormone-naïve early PCa and demonstrated its correlation with biochemical recurrence and distant metastasis, independent of clinical characteristics. We show that progression toward castration resistance was initiated from subtype-specific lineage plasticity and clonal expansion of pre-existing neuroendocrine and CRPC-like cells in early PCa. CONCLUSIONS: CRPC-like cells are present early in the development of PCa and are not exclusively the result of acquired evolutionary selection during androgen deprivation therapy. The lethal CRPC and SCNC phenotypes should be targeted earlier in the disease course of patients with PCa. PATIENT SUMMARY: Here, we report the presence of pre-existing castration-resistant prostate cancer (CRPC)-like cells in primary prostate cancer, which represents a novel castration-resistant mechanism different from the adaptation mechanism after androgen deprivation therapy (ADT). Patients whose tumors harbor increased pre-existing neuroendocrine and CRPC-like cells may become rapidly resistant to ADT and may require aggressive early intervention.

INTRODUCTION: Despite some of the oncogenic driver mutations that have been associated with increased expression of programmed death-ligand 1 (PD-L1), the correlation between PD-L1 expression and ROS1 fusion in NSCLC cells, especially for those with Crizotinib resistance has not been fully addressed. MATERIALS AND METHODS: The expression of PD-L1 in 30 primary NSCLC tumors with/without ROS1-fusion protein was evaluated by immunohistochemical (IHC) analysis. To assess the correlation between ROS1 fusion and PD-L1 expression, we down-regulated ROS1 with RNA interference or specific inhibitor (Crizotinib) in ROS1-fusion positive NSCLC cell line HCC78; or up-regulate ROS1-fusion gene in an immortalized human bronchial epithelial cell line (HBE). Mouse xenograft models were also used to determine the effect of ROS1 expression on PD-L1 expression in vivo. Crizotinib-resistant cell line was generated for measuring the association between Crizotinib resistance and PD-L1 expression. RESULTS: ROS1-rearrangement in primary NSCLC tumor was significantly associated with up-regulated PD-L1 expression. PD-L1 expression was significantly up-regulated in bronchial epithelial cells after forced expression of ROS1 fusion and was eliminated when HCC78 xenograft mouse models were treated with Crizotinib. We found PD-L1 expression was modulated by MEK-ERK pathway signaling in both parental and Crizotinib-resistant NSCLC cells with ROS1 fusion. CONCLUSIONS: The correlation between ROS1-fusion and PD-L1 overexpression suggested that PD-L1/PD-1 blockade could be the second-line treatment option for the Crizotinib-resistant NSCLC with ROS1 rearrangement.

Acute rejection (AR) remains a significant problem that negatively impacts long-term renal allograft survival. Numerous therapies are used to prevent AR that differ by center and recipient age. This variability confounds diagnostic methods. Methods: To develop an age-independent gene signature for AR effective across a broad array of immunosuppressive regimens, we compiled kidney transplant biopsy (n=1091) and peripheral blood (n=392) gene expression profiles from 12 independent public datasets. After removing genes differentially expressed in pediatric and adult patients, we compared gene expression profiles from biopsy and peripheral blood samples of patients with AR to those who were stable (STA), using Mann-Whitney U Tests with validation in independent testing datasets. We confirmed this signature in pediatric and adult patients (42 AR and 47 STA) from our institutional biorepository. Results: We identified a novel age-independent gene network that identified AR from both kidney and blood samples. We developed a 90-probe set signature targeting 76 genes that differentiated AR from STA and found an 8 gene subset (DIP2C, ENOSF1, FBXO21, KCTD6, PDXDC1, REXO2, HLA-E, and RAB31) that was associated with AR. Conclusion: We used publicly available datasets to create a gene signature of AR that identified AR irrespective of immunosuppression regimen or recipient age. This study highlights a novel model to screen and validate biomarkers across multiple treatment regimens.

Hormonal therapy targeting androgen receptor (AR) is initially effective to treat prostate cancer (PCa), but it eventually fails. It has been hypothesized that cellular heterogeneity of PCa, consisting of AR+ luminal tumor cells and AR- neuroendocrine (NE) tumor cells, may contribute to therapy failure. Here, we describe the successful purification of NE cells from primary fresh human prostate adenocarcinoma based on the cell surface receptor C-X-C motif chemokine receptor 2 (CXCR2). Functional studies revealed CXCR2 to be a driver of the NE phenotype, including loss of AR expression, lineage plasticity, and resistance to hormonal therapy. CXCR2-driven NE cells were critical for the tumor microenvironment by providing a survival niche for the AR+ luminal cells. We demonstrate that the combination of CXCR2 inhibition and AR targeting is an effective treatment strategy in mouse xenograft models. Such a strategy has the potential to overcome therapy resistance caused by tumor cell heterogeneity.

The ability of leukemia cells to accumulate methotrexate polyglutamate (MTXPG) is an important determinant of the antileukemic effects of methotrexate (MTX). We measured in vivo MTXPG accumulation in leukemia cells from 101 children with acute lymphoblastic leukemia (ALL) and established that B-lineage ALL with either TEL-AML1 or E2A-PBX1 gene fusion, or T-lineage ALL, accumulates significantly lower MTXPG compared with B-lineage ALL without these genetic abnormalities or compared with hyperdiploid (fewer than 50 chromosomes) ALL. To elucidate mechanisms underlying these differences in MTXPG accumulation, we used oligonucleotide microarrays to analyze expression of 32 folate pathway genes in diagnostic leukemia cells from 197 children. This revealed ALL subtype-specific patterns of folate pathway gene expression that were significantly related to MTXPG accumulation. We found significantly lower expression of the reduced folate carrier (SLC19A1, an MTX uptake transporter) in E2A-PBX1 ALL, significantly higher expression of breast cancer resistance protein (ABCG2, an MTX efflux transporter) in TEL-AML1 ALL, and lower expression of FPGS (which catalyzes formation of MTXPG) in T-lineage ALL, consistent with lower MTXPG accumulation in these ALL subtypes. These findings reveal distinct mechanisms of subtype-specific differences in MTXPG accumulation and point to new strategies to overcome these potential causes of treatment failure in childhood ALL.