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Logothetis, C. J.

Publications and source records attributed to Logothetis, C. J..

8 recordsLinked to original sources

Integrative analysis of the MD Anderson Prostate Cancer Patient-Derived Xenograft Series (MDA PCa PDX)

Progress in understanding prostate cancer (PCa) metastasis and therapy resistance has been hampered by the lack of models, representative of the clinical spectrum and biologic complexity of the disease. Our laboratory is home to one of the largest worldwide repositories of PCa patient-derived xenografts (PDXs), the MDA PCa PDX series, a collection of clinically annotated PDXs reflecting the full spectrum of potentially lethal disease, that includes tumors that are not end stage and not castration-resistant PCa. We performed whole genome sequencing, targeted sequencing and RNA sequencing of 46 MDA PCa PDX models derived from biopsy and surgical specimens from 39 patients, selected in order to reflect the clinicopathological PCa subtypes (data available in cBioPortal). MDA PCa PDXs genomic characterization shows that the cohort recapitulates the mutational landscape found in PCa, highlighting the clinical relevance of these models. Interestingly and consistently with the clinic, certain models lack the typical PCa driver alterations, thus providing a suitable tool for discovery of novel drivers. Our cohort also includes PDXs derived from different areas of the same tumor and longitudinal samples, allowing to study disease heterogeneity and progression. Finally, we have developed a procedure to grow organoids from PDXs, thus providing a powerful in vitro platform that supports hypothesis generation, and testing of clinically relevant observations. Genomic and transcriptomic characterization of MDA PCa PDXs together with the ability to grow them as organoids for in vitro experimentation, provides a unique resource to address the existing clinical gap in PCa, helping to better understand mechanisms of response and resistance. One Sentence SummaryMDA PCa PDX series is a dynamic resource capturing the molecular landscape of prostate cancer; a platform for discovery and personalized medicine

cancer biology↗

KDM4A promotes NEPC progression through regulation of MYC expression

Neuroendocrine prostate cancer (NEPC) represents one of the most lethal forms of prostate cancer (PCa) and lacks life-prolonging treatment. The incidence of NEPC is increased due to the widespread use of AR pathway inhibitors (ARPIs) in the treatment of non-metastatic CRPC and hormone-sensitive metastatic tumors. Here, we identified histone lysine demethylase KDM4A as a key player in NEPC progression and an effective therapeutic target. We found that KDM4A mRNA and protein are overexpressed in human and mouse NEPC compared to prostate adenocarcinoma. Knockdown (KD) or knockout (KO) of KDM4A in NEPC cell lines suppressed cancer cell growth in vitro and in vivo. Mechanistically, we found that KDM4A promotes NEPC progression, in part, through direct transcriptional regulation of MYC. We showed that MYC is hyper-activated in human and mouse NEPC. KDM4A KD led to suppression of MYC signaling. MYC KD or inhibition profoundly suppressed NEPC cell proliferation. Furthermore, a potent pan-KDM4 inhibitor QC6352 significantly reduced NEPC cell growth in vitro and in vivo. Taken together, we demonstrated that KDM4A is an important regulator of NEPC progression and targeting KDM4A may potentially be an effective therapeutic strategy for NEPC. SignificanceNeuroendocrine prostate cancer (NEPC) is a highly aggressive prostate cancer subtype that is resistant to potent androgen receptor pathway inhibitors (ARPIs) and currently lacks effective therapeutic options. Histone lysine demethylase KDM4A is an important epigenetic regulator of gene expression in development and cancer. In this study, we show that KDM4A is highly expressed in NEPC and is required for NEPC proliferation, anchorage-independent growth, and in vivo growth, which is in part mediated through the regulation of MYC expression. Importantly, we demonstrate that inhibition of KDM4A significantly impairs NEPC growth in preclinical models. Thus, our findings provide valuable insights into the molecular mechanisms underlying NEPC progression and offer a rationale for clinical trials with KDM4 inhibitor in NEPC patients.

cancer biology↗

Activation of retinoic acid receptor reduces metastatic prostate cancer bone lesions through blocking endothelial-to-osteoblast transition

Metastatic prostate cancer (PCa) in bone induces bone-forming lesions that contribute to progression and therapy resistance. Currently strategies targeting PCa-induced bone formation are lacking. We previously showed that PCa-induced bone originates from endothelial cells (EC) that have undergone endothelial-to-osteoblast (EC-to-OSB) transition in response to tumor-secreted BMP4. Here, we show that activation of retinoic acid receptor (RAR) inhibits EC-to-OSB transition and reduces PCa-induced bone formation. We found that palovarotene, a RAR{gamma} agonist being tested for heterotopic ossification in fibrodysplasia ossificans progressiva, inhibited EC-to-OSB transition and osteoblast mineralization in vitro, and decreased tumor-induced bone formation and tumor growth in several osteogenic PCa models. RAR/{beta}/{gamma} isoform knockdown in 2H11 ECs blocked EC-to-OSB transition and osteoblast mineralization. Pan-RAR agonist ATRA inhibited MycCaP-BMP4-induced bone formation and tumor growth under castration. Furthermore, palovarotene or ATRA reduced plasma Tenascin C, a factor secreted by EC-OSB cells, which may be used to monitor treatment response. Mechanistically, BMP4-activated pSmad1 forms a complex with RAR in the nucleus of 2H11 cells. RAR activation by palovarotene or ATRA causes pSmad1 degradation by recruiting E3-ubiquitin ligase Smurf1 into the nuclear pSmad1/RAR{gamma} complex. Our findings suggest that palovarotene can be repurposed to target PCa-induced bone formation to improve clinical outcomes for bone metastasis.

cancer biology↗

Prostate tumor-induced stromal reprogramming generates Tenascin C that promotes prostate cancer metastasis through YAP/TAZ inhibition

Metastatic prostate cancer (PCa) in bone induces bone-forming lesions that enhance PCa progression. How tumor-induced bone formation enhances PCa progression is not known. We have previously shown that PCa-induced bone originates from endothelial cells (EC) that have undergone endothelial-to-osteoblast (EC-to-OSB) transition by tumor-secreted BMP4. Here, we show that EC-to-OSB transition leads to changes in the tumor microenvironment that increases the metastatic potential of PCa cells. We found that conditioned medium (CM) from EC-OSB hybrid cells increases the migration, invasion and survival of PC3-mm2 and C4-2B4 PCa cells. Quantitative mass spectrometry (iTRAQ) identified Tenascin C (TNC) as one of the major proteins secreted from EC-OSB hybrid cells. TNC expression in tumor-induced osteoblasts was confirmed by immunohistochemistry of MDA-PCa118b xenograft and human bone metastasis specimens. Mechanistically, BMP4 increases TNC expression in EC-OSB cells through the Smad1-Notch/Hey1 pathway. How TNC promotes PCa metastasis was next interrogated by in vitro and in vivo studies. In vitro studies showed that a TNC neutralizing antibody inhibits EC-OSB-CM-mediated PCa cell migration and survival. TNC knockdown decreased, while addition of recombinant TNC or TNC overexpression increased migration and anchorage-independent growth of PC3 or C4-2b cells. When injected orthotopically, PC3-mm2-shTNC clones decreased metastasis to bone, while C4-2b-TNC overexpressing cells increased metastasis to lymph nodes. TNC enhances PCa cell migration through 5{beta}1 integrin-mediated YAP/TAZ inhibition. These studies elucidate that tumor-induced stromal reprogramming generates TNC that enhances PCa metastasis and suggest that TNC may be a target for PCa therapy.

cancer biology↗

H3K4me1-marked Enhancer Activation in Resistant Prostate Cancers Implicates SOX4 and MENIN Inhibition as Therapeutic Strategies

Chromatin elements and regulators play important roles during progression of prostate cancer, however, their involvement in response to therapy is less well understood. Using comprehensive chromatin profiling of patient-derived tumors, we find that enhancer elements marked by H3K4me1 are highly enriched in aggressive therapy-resistant prostate cancers on important resistance-driving genes, such as those involved in FOXA1, NOTCH and TGF-{beta} signaling. Importantly, by targeting H3K4me1-elements through inhibition of the MLL complex, a H3K4 methyltransferase, we reduced the proliferative capacity and H3K4me1-associated loci in enzalutamide-resistant prostate cancer lines. We identify AR, FOXA1, HOXB13 and SOX4 as a subset of core TFs that are critical for establishing transcriptional networks via active enhancer reprogramming during acquisition of resistance to therapy. Knock-down of SOX4 reduced cell proliferation and disrupted the H3K4me1 enhancer landscape, further suggesting a role for this TF in therapy-resistance. Overall, our data implicate H3K4me1-marked enhancers as a key epigenetic feature of therapy-resistance, implicate SOX4 in enhancer reprogramming and suggest use of MLL/MENIN inhibitors as a potential therapeutic strategy in high-grade and locally advanced prostate cancers that do not respond to traditional therapies.

cancer biology↗

Measuring the metabolic evolution of glioblastoma throughout tumor development, regression, and recurrence with hyperpolarized magnetic resonance

Rapid diagnosis and therapeutic monitoring of aggressive diseases such as glioblastoma can improve patient survival by providing physicians the time to optimally deliver treatment. This research tested whether metabolic imaging with hyperpolarized MRI could detect changes in tumor progression faster than conventional anatomic MRI in patient-derived glioblastoma murine models. To capture the dynamic nature of cancer metabolism, hyperpolarized MRI, NMR spectroscopy, and immunohistochemistry were performed at several time-points during tumor development, regression, and recurrence. Hyperpolarized MRI detected significant changes of metabolism throughout tumor progression whereas conventional MRI was less sensitive. This was accompanied by aberrations in amino acid and phospholipid lipid metabolism and MCT1 expression. Hyperpolarized MRI can help address clinical challenges such as identifying malignant disease prior to aggressive growth, differentiating pseudoprogression from true progression, and predicting relapse. The individual evolution of these metabolic assays as well as their correlations with one another provides context for further academic research.

biophysics↗

Transcriptional Inactivation of TP53 and the BMP Pathway Mediates Therapy-induced Dedifferentiation and Metastasis in Prostate Cancer

Unsupervised clustering and deconvolution analysis identifies a novel subtype of M-CRPC endowed with hybrid epithelial/mesenchymal (E/M) and luminal progenitor-like traits (Mesenchymal and Stem-like PC, MSPC). Analysis of patient datasets and mechanistic studies indicate that MSPC arises as a consequence of therapy-induced lineage plasticity. AR blockade instigates two separate and complementary processes: 1) transcriptional silencing of TP53 and hence acquisition of hybrid E/M and stem-like traits; and 2) inhibition of the BMP signaling, which promotes resistance to the pro-apoptotic and anti-proliferative effects of AR inhibition. The drug-tolerant prostate cancer cells generated through reprogramming are rescued by neuregulin and generate metastases in mice. Combined inhibition of HER2/3 and AR or mTORC1 exhibit efficacy in preclinical models of mixed ARPC/MSPC or MSPC, respectively. These results identify a novel subtype of M-CRPC, trace its origin to therapy-induced lineage plasticity, and reveal its dependency on HER2/3 signaling.

cancer biology↗

P4HA2-induced prolyl hydroxylation suppresses YAP1-mediated prostate cancer cell migration, invasion, and metastasis

Yes-associated protein 1 (YAP1), a key player in the Hippo pathway, has been shown to play a critical role in tumor progression. However, the role of YAP1 in prostate cancer cell invasion, migration, and metastasis is not well defined. Through functional, transcriptomic, epigenomic, and proteomic analyses, we showed that prolyl hydroxylation of YAP1 plays a critical role in the suppression of cell migration, invasion, and metastasis in prostate cancer. Knockdown (KD) or knockout (KO) of YAP1 led to an increase in cell migration, invasion, and metastasis in prostate cancer cells. Microarray analysis showed that the EMT pathway was activated in Yap1-KD cells. ChIP-seq analysis showed that YAP1 target genes are enriched in pathways regulating cell migration. Mass spectrometry analysis identified P4H prolyl hydroxylase in the YAP1 complex and YAP1 was hydroxylated at multiple proline residues. Proline-to-alanine mutations of YAP1 isoform 3 identified proline 174 as a critical residue, and its hydroxylation suppressed cell migration, invasion, and metastasis. KO of P4ha2 led to an increase in cell migration and invasion, which was reversed upon Yap1 KD. Our study identified a novel regulatory mechanism of YAP1 by which P4HA2-dependent prolyl hydroxylation of YAP1 determines its transcriptional activities and its function in prostate cancer metastasis.

cancer biology↗