Toward a CRISPR-based mouse model of -deficient clear cell kidney cancer: Initial experience and lessons learned.

CRISPR is revolutionizing the ability to do somatic gene editing in mice for the purpose of creating new cancer models. Inactivation of the tumor suppressor gene is the signature initiating event in the most common form of kidney cancer, clear cell renal cell carcinoma (ccRCC). Such tumors are usually driven by the excessive HIF2 activity that arises when the gene product, pVHL, is defective.

Interplay of IGF1R and estrogen signaling regulates hematopoietic stem and progenitor cells.

Tissue stem cells often exhibit developmental stage-specific and sexually dimorphic properties, but the underlying mechanism remains largely elusive. By characterizing IGF1R signaling in hematopoietic cells, here we report that its disruption exerts sex-specific effects in adult hematopoietic stem and progenitor cells (HSPCs). Loss of IGF1R decreases the HSPC population in females but not in males, in part due to a reduction in HSPC proliferation induced by estrogen.

Single-Cell Analysis Identifies NOTCH3-Mediated Interactions between Stromal Cells That Promote Microenvironment Remodeling and Invasion in Lung Adenocarcinoma.

Unlabelled: Cancer immunotherapy has revolutionized the treatment of lung adenocarcinoma (LUAD); however, a significant proportion of patients do not respond. Recent transcriptomic studies to understand determinants of immunotherapy response have pinpointed stromal-mediated resistance mechanisms. To gain a better understanding of stromal biology at the cellular and molecular level in LUAD, we performed single-cell RNA sequencing of 256,379 cells, including 13,857 mesenchymal cells, from 9 treatment-naïve patients.

Reverse Translating Molecular Determinants of Anti-Programmed Death 1 Immunotherapy Response in Mouse Syngeneic Tumor Models.

Targeting the programmed death 1/programmed death ligand 1 (PD-1/PD-L1) pathway with immunotherapy has revolutionized the treatment of many cancers. Somatic tumor mutational burden (TMB) and T-cell-inflamed gene expression profile (GEP) are clinically validated pan-tumor genomic biomarkers that can predict responsiveness to anti-PD-1/PD-L1 monotherapy in many tumor types. We analyzed the association between these biomarkers and the efficacy of PD-1 inhibitor in 11 commonly used preclinical syngeneic tumor mouse models using murinized rat anti-mouse PD-1 DX400 antibody muDX400, a surrogate for pembrolizumab.

Single-Cell Analysis Identifies LY6D as a Marker Linking Castration-Resistant Prostate Luminal Cells to Prostate Progenitors and Cancer.

The exact identity of castrate-resistant (CR) cells and their relation to CR prostate cancer (CRPC) is unresolved. We use single-cell gene profiling to analyze the molecular heterogeneity in basal and luminal compartments. Within the luminal compartment, we identify a subset of cells intrinsically resistant to castration with a bi-lineage gene expression pattern.

Protocols for Studies on TMPRSS2/ERG in Prostate Cancer.

TMPRSS2/ERG is the most common type of gene fusions found in human prostate cancer. There are two important features of TMPRSS2/ERG fusions. One is that these gene fusions lead to ectopic expression of ERG, an ETS family transcription factor, in prostate epithelial cells from the 5' control region of an androgen/estrogen dual-responsive gene, TMPRSS2; the other is that ~60% of these fusions are generated via intrachromosomal deletion of the interstitial region between TMPRSS2 and ERG.

Deletion of Interstitial Genes between TMPRSS2 and ERG Promotes Prostate Cancer Progression.

TMPRSS2-ERG gene fusions that occur frequently in human prostate cancers can be generated either through insertional chromosomal rearrangement or by intrachromosomal deletion. Genetically, a key difference between these two mechanisms is that the latter results in deletion of a ∼3-Mb interstitial region containing genes with unexplored roles in prostate cancer. In this study, we characterized two mouse models recapitulating TMPRSS2-ERG insertion or deletion events in the background of prostate-specific PTEN deficiency.

Genetic interaction between Tmprss2-ERG gene fusion and Nkx3.1-loss does not enhance prostate tumorigenesis in mouse models.

Gene fusions involving ETS family transcription factors (mainly TMPRSS2-ERG and TMPRSS2-ETV1 fusions) have been found in ~50% of human prostate cancer cases. Although expression of TMPRSS2-ERG or TMPRSS2-ETV1 fusion alone is insufficient to initiate prostate tumorigenesis, they appear to sensitize prostate epithelial cells for cooperation with additional oncogenic mutations to drive frank prostate adenocarcinoma. To search for such ETS-cooperating oncogenic events, we focused on a well-studied prostate tumor suppressor NKX3.

Pim-1 kinase phosphorylates and stabilizes 130 kDa FLT3 and promotes aberrant STAT5 signaling in acute myeloid leukemia with FLT3 internal tandem duplication.

The type III receptor tyrosine kinase fms-like tyrosine kinase 3 (FLT3) is expressed on both normal hematopoietic stem cells and acute myeloid leukemia (AML) cells and regulates their proliferation. Internal tandem duplication (ITD) mutation of FLT3 is present in a third of AML cases, results in constitutive activation and aberrant signaling of FLT3, and is associated with adverse treatment outcomes. While wild-type (WT) FLT3 is predominantly a 150 kDa complex glycosylated cell surface protein, FLT3-ITD is partially retained in the endoplasmic reticulum as a 130 kDa underglycosylated species associated with the chaperones calnexin and heat shock protein (HSP) 90, and mediates aberrant STAT5 signaling, which upregulates the oncogenic serine/threonine kinase Pim-1.

ETV1 directs androgen metabolism and confers aggressive prostate cancer in targeted mice and patients.

Distinguishing aggressive from indolent disease and developing effective therapy for advanced disease are the major challenges in prostate cancer research. Chromosomal rearrangements involving ETS transcription factors, such as ERG and ETV1, occur frequently in prostate cancer. How they contribute to tumorigenesis and whether they play similar or distinct in vivo roles remain elusive.

Differential regulation of androgen receptor by PIM-1 kinases via phosphorylation-dependent recruitment of distinct ubiquitin E3 ligases.

Androgen receptor (AR) plays a pivotal role in prostate cancer. Regulation of AR transcriptional activity by post-translational modifications, such as phosphorylation by multiple kinases, is well documented. Here, we report that two PIM-1 kinase isoforms which are up-regulated during prostate cancer progression, namely PIM-1S and PIM-1L, modulate AR stability and transcriptional activity through differentially phosphorylating AR at serine 213 (Ser-213) and threonine 850 (Thr-850).

A Role for OCT4 in Tumor Initiation of Drug-Resistant Prostate Cancer Cells.

Drug resistance remains a clinical challenge in cancer treatment due to poor understanding of underlying mechanisms. We have established several drug-resistant prostate cancer cell lines by long-term culture in medium containing chemotherapeutic drugs. These resistant lines displayed a significant increase in side population cells due to overexpression of drug efflux pumps including ABCG2/BCRP and MDR1/Pgp.

Compensatory upregulation of tyrosine kinase Etk/BMX in response to androgen deprivation promotes castration-resistant growth of prostate cancer cells.

We previously showed that targeted expression of non-receptor tyrosine kinase Etk/BMX in mouse prostate induces prostate intraepithelial neoplasia, implying a possible causal role of Etk in prostate cancer development and progression. Here, we report that Etk is upregulated in both human and mouse prostates in response to androgen ablation. Etk expression seems to be differentially regulated by androgen and interleukin 6 (IL-6), which is possibly mediated by the androgen receptor (AR) in prostate cancer cells.

Pim-1 kinase protects P-glycoprotein from degradation and enables its glycosylation and cell surface expression.

The oncogenic serine/threonine kinase Pim-1 phosphorylates and activates the ATP-binding cassette transporter breast cancer resistance protein (ABCG2). The ABC transporter P-glycoprotein (Pgp; ABCB1) also contains a Pim-1 phosphorylation consensus sequence, and we hypothesized that Pim-1 also regulates Pgp. Pgp is exported from the endoplasmic reticulum (ER) as a 150-kDa species that is glycosylated to 170-kDa Pgp, translocates to the cell surface, and mediates drug efflux; alternatively, 150-kDa Pgp is cleaved to a 130-kDa proteolytic product by ER proteases or undergoes ubiquitination and proteasomal degradation.

Regulation of androgen receptor transcriptional activity and specificity by RNF6-induced ubiquitination.

The androgen receptor (AR) plays a critical role in prostate cancer. We have identified a ubiquitin E3 ligase, RNF6, as an AR-associated protein in a proteomic screen. RNF6 induces AR ubiquitination and promotes AR transcriptional activity.

A novel androgen receptor splice variant is up-regulated during prostate cancer progression and promotes androgen depletion-resistant growth.

The androgen receptor (AR) plays a key role in progression to incurable androgen ablation-resistant prostate cancer (PCA). We have identified three novel AR splice variants lacking the ligand-binding domain (designated as AR3, AR4, and AR5) in hormone-insensitive PCA cells. AR3, one of the major splice variants expressed in human prostate tissues, is constitutively active, and its transcriptional activity is not regulated by androgens or antiandrogens.

The 44-kDa Pim-1 kinase phosphorylates BCRP/ABCG2 and thereby promotes its multimerization and drug-resistant activity in human prostate cancer cells.

We previously showed that the 44-kDa serine/threonine kinase Pim-1 (Pim-1L) can protect prostate cancer cells from apoptosis induced by chemotherapeutic drugs (Xie, Y., Xu, K., Dai, B.