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Lung squamous cell carcinoma (LUSC) represents a minor proportion of nonsmall cell lung cancer (NSCLC) harboring a poor prognosis. Herein, retrospective medical record research was performed to investigate real-world treatment patterns and identify the prognostic factors among LUSC patients. A total of 173 patients with a median age of 68 years were enrolled for analysis. Males were predominant (n = 143, 83%) and current or ex-smokers contributed to 78% of the entire cohort. Pleura and lung were the most common metastatic sites, whereas brain metastasis was only 7%. After diagnosis, however, only 107 patients (62%) had received first-line chemotherapy. In the chemotherapy cohort, median progression-free survival (PFS) and overall survival (OS) were 3.9 and 11.1 months, respectively. After multivariable analysis, bone metastasis and the use of first-line single-agent chemotherapy independently predicted shorter PFS. For baseline characteristics, male sex, metastasis to lung, pleura, liver, and bone independently predicted worse OS. Regarding the treatment pattern, patients who had undergone standard first-line doublet therapy and employed targeted therapies after disease progression linked to longer OS. In the real world, even those who underwent chemotherapy still had poor outcome. The findings may help clinicians to orchestrate the treatment strategies for LUSC patients and provide further direction of large-scale studies.

Prostate cancer remains among the leading causes of cancer-related deaths in men. Patients with aggressive disease typically undergo hormone deprivation therapy. Although treatment is initially very successful, these men commonly progress to lethal, castration-resistant prostate cancer (CRPC) in 2 to 3 years. Standard therapies for CRPC include second-generation antiandrogens, which prolong patient lifespan by only several months. It is imperative to advance our understanding of the mechanisms leading to resistance to identify new therapies for aggressive prostate cancer. This study identifies Notch1 as a therapeutic target in prostate cancer. Loss of NOTCH1 in aggressive prostate cancer cells decreases proliferation, invasion, and tumorsphere formation. Therapeutic inhibition of Notch1 activity with gamma secretase inhibitors RO4929097 or DAPT in prostate cancer cells further results in decreased proliferative abilities. Loss of NOTCH1 and treatment of immunocompromised mice bearing prostate cancer xenografts with RO4929097 display significantly impaired tumor growth. Loss of NOTCH1 additionally decreased metastatic potential of prostate cancer cells in invasion assays in vitro as well as in vivo experiments. Moreover, treatment with gamma secretase inhibitors or NOTCH1 gene deletion synergized with antiandrogen therapies, enzalutamide or abiraterone, to decrease the growth of prostate cancer cells. Combination of gamma secretase inhibitors with abiraterone significantly inhibited cell migration and invasion, while combination with enzalutamide reversed enzalutamide-induced migration and invasion. These collective findings suggest loss of NOTCH1 delays growth of CRPC and inhibits metastasis, and inhibition of Notch1 activation in conjunction with second-generation antiandrogen therapies could delay growth and progression of prostate cancer.

Supplementary Figure 1. Quantification of immunoblotting in Figure 1. Supplementary Figure 2. Animal weights from Figure 3 xenografts. Supplementary Figure 3. Quantification of immunoblotting from xenograft tissues in Figure 3. Supplementary Figure 4. Viability of GSI combination therapy with anti-androgens Enzalutamide or Abiraterone. Supplementary Figure 5. GSI and anti-Androgen therapies synergize to decrease colony formation of CRPC cells. Supplementary Figure 6. GSIs synergize with anti-androgens Enzalutamide and Abiraterone to inhibit prostate cancer cell migration in vitro. Supplementary Figure 7. Matrigel Dot assay performed on 22RV1 cells was not able to assay migration.

Supplementary Figures and Supplementary Figure Legends 1-4

Ferroptosis is a type of programmed cell death induced by the accumulation of lipid peroxidation and lipid reactive oxygen species in cells. It has been recently demonstrated that cancer cells are vulnerable to ferroptosis inducers (FIN). However, the therapeutic potential of FINs in prostate cancer in preclinical settings has not been explored. In this study, we demonstrate that mediators of ferroptosis, solute carrier family 7 member 11, SLC3A2, and glutathione peroxidase, are expressed in treatment-resistant prostate cancer. We further demonstrate that treatment-resistant prostate cancer cells are sensitive to two FINs, erastin and RSL3. Treatment with erastin and RSL3 led to a significant decrease in prostate cancer cell growth and migration in vitro and significantly delayed the tumor growth of treatment-resistant prostate cancer in vivo, with no measurable side effects. Combination of erastin or RSL3 with standard-of-care second-generation antiandrogens for advanced prostate cancer halted prostate cancer cell growth and migration in vitro and tumor growth in vivo. These results demonstrate the potential of erastin or RSL3 independently and in combination with standard-of-care second-generation antiandrogens as novel therapeutic strategies for advanced prostate cancer.Significance:These findings reveal that induction of ferroptosis is a new therapeutic strategy for advanced prostate cancer as a monotherapy and in combination with second-generation antiandrogens.

Prostate cancer is one of the most common malignancies worldwide, yet limited tools exist for prognostic risk stratification of the disease. Identification of new biomarkers representing intrinsic features of malignant transformation and development of prognostic imaging technologies are critical for improving treatment decisions and patient survival. In this study, we analyzed radical prostatectomy specimens from 422 patients with localized disease to define the expression pattern of methionine aminopeptidase II (MetAP2), a cytosolic metalloprotease that has been identified as a druggable target in cancer. MetAP2 was highly expressed in 54% of low-grade and 59% of high-grade cancers. Elevated levels of MetAP2 at diagnosis were associated with shorter time to recurrence. Controlled self-assembly of a synthetic small molecule enabled design of the first MetAP2-activated PET imaging tracer for monitoring MetAP2 activity in vivo. The nanoparticles assembled upon MetAP2 activation were imaged in single prostate cancer cells with post-click fluorescence labeling. The fluorine-18–labeled tracers successfully differentiated MetAP2 activity in both MetAP2-knockdown and inhibitor-treated human prostate cancer xenografts by micro-PET/CT scanning. This highly sensitive imaging technology may provide a new tool for noninvasive early-risk stratification of prostate cancer and monitoring the therapeutic effect of MetAP2 inhibitors as anticancer drugs.Significance:This study defines MetAP2 as an early-risk stratifier for molecular imaging of aggressive prostate cancer and describes a MetAP2-activated self-assembly small-molecule PET tracer for imaging MetAP2 activity in vivo.

Methods, Figures S1-21, NMR & MS spectra

Movie of super-resolution imaging of assembled probes in a single cell.

BACKGROUND: Distinguishing men with aggressive from indolent prostate cancer is critical to decisions in the management of clinically localized prostate cancer. Molecular signatures of aggressive disease could help men overcome this major clinical challenge by reducing unnecessary treatment and allowing more appropriate treatment of aggressive disease. METHODS: We performed a mass spectrometry-based proteomic analysis of normal and malignant prostate tissues from 22 men who underwent surgery for prostate cancer. Prostate cancer samples included Grade Groups (3 to 5), with 8 patients experiencing recurrence and 14 without evidence of recurrence with a mean of 6.8 years of follow-up. To better understand the biological pathways underlying prostate cancer aggressiveness, we performed a systems biology analysis and gene enrichment analysis. Proteins that distinguished recurrent from non-recurrent cancer were chosen for validation by immunohistochemical analysis on tissue microarrays containing samples from a larger cohort of patients with recurrent and non-recurrent prostate cancer. RESULTS: 24,037 unique peptides (false discovery rate < 1%) corresponding to 3,313 distinct proteins were identified with absolute abundance ranges spanning seven orders of magnitude. Of these proteins, 115 showed significantly (P < 0.01) different levels in tissues from recurrent versus non-recurrent cancers. Analysis of all differentially expressed proteins in recurrent and non-recurrent cases identified several protein networks, most prominently one in which approximately 24% of the proteins in the network were regulated by the YY1 transcription factor (adjusted P < 0.001). Strong immunohistochemical staining levels of three differentially expressed proteins, POSTN, CALR, and CTSD, on a tissue microarray validated their association with shorter patient survival. CONCLUSIONS: The protein signatures identified could improve understanding of the molecular drivers of aggressive prostate cancer and be used as candidate prognostic biomarkers.

Distant metastasis is the main cause of death in prostate cancer patients. Notch signaling plays an important role in driving prostate cancer aggressiveness and metastasis. In this chapter, we describe a protocol to measure prostate cancer metastatic colonization, incidences of metastasis, accurately quantify the burden of metastasis, and test the role of NOTCH1 receptor on prostate cancer metastatic colonization and homing to distant sites. The metastasis model presented here is established by intracardiac injection of control human prostate cancer cells and NOTCH1 downregulated cells. The cells are engineered to express both red fluorescent protein (RFP) and luciferase. In this model, whole body bioluminescence imaging, high-resolution, and quantitative fluorescence imaging are utilized for quantitative assessment of metastatic colonization and metastasis burden. Further, histopathology analyses of diverse metastatic organs are performed. This model is a powerful and versatile tool to investigate the mechanisms underlying the function of NOTCH receptors in metastatic colonization in prostate cancer.

Organized assemblies of cells have demonstrated promise as bioinspired actuators and devices; still, the fabrication of such "biorobots" has predominantly relied on passive assembly methods that reduce design capabilities. To address this, we have developed a strategy for the rapid formation of functional biorobots composed of live cardiomyocytes. We employ tunable acoustic fields to facilitate the efficient aggregation of millions of cells into high-density macroscopic architectures with directed cell orientation and enhanced cell-cell interaction. These biorobots can perform actuation functions both through naturally occurring contraction-relaxation cycles and through external control with chemical and electrical stimuli. We demonstrate that these biorobots can be used to achieve controlled actuation of a soft skeleton and pumping of microparticles. The biocompatible acoustic assembly strategy described here should prove generally useful for cellular manipulation in the context of tissue engineering, soft robotics, and other applications.

Molecular imaging is a crucial technique in clinical diagnostics but it relies on radioactive tracers or strong magnetic fields that are unsuitable for many patients, particularly infants and pregnant women. Ultra-high-frequency radio-frequency acoustic (UHF-RF-acoustic) imaging using non-ionizing RF pulses allows deep-tissue imaging with sub-millimetre spatial resolution. However, lack of biocompatible and targetable contrast agents has prevented the successful in vivo application of UHF-RF-acoustic imaging. Here we report our development of targetable nanodroplets for UHF-RF-acoustic molecular imaging of cancers. We synthesize all-liquid nanodroplets containing hypertonic saline that are stable for at least 2 weeks and can produce high-intensity UHF-RF-acoustic signals. Compared with concentration-matched iron oxide nanoparticles, our nanodroplets produce at least 1,600 times higher UHF-RF-acoustic signals at the same imaging depth. We demonstrate in vivo imaging using the targeted nanodroplets in a prostate cancer xenograft mouse model expressing gastrin release protein receptor (GRPR), and show that targeting specificity is increased by more than 2-fold compared with untargeted nanodroplets or prostate cancer cells not expressing this receptor.

Prostate cancer is one of the most common malignancies worldwide, yet limited tools exist for prognostic risk stratification of the disease. Identification of new biomarkers representing intrinsic features of malignant transformation and development of prognostic imaging technologies are critical for improving treatment decisions and patient survival. In this study, we analyzed radical prostatectomy specimens from 422 patients with localized disease to define the expression pattern of methionine aminopeptidase II (MetAP2), a cytosolic metalloprotease that has been identified as a druggable target in cancer. MetAP2 was highly expressed in 54% of low-grade and 59% of high-grade cancers. Elevated levels of MetAP2 at diagnosis were associated with shorter time to recurrence. Controlled self-assembly of a synthetic small molecule enabled design of the first MetAP2-activated PET imaging tracer for monitoring MetAP2 activity in vivo. The nanoparticles assembled upon MetAP2 activation were imaged in single prostate cancer cells with post-click fluorescence labeling. The fluorine-18–labeled tracers successfully differentiated MetAP2 activity in both MetAP2-knockdown and inhibitor-treated human prostate cancer xenografts by micro-PET/CT scanning. This highly sensitive imaging technology may provide a new tool for noninvasive early-risk stratification of prostate cancer and monitoring the therapeutic effect of MetAP2 inhibitors as anticancer drugs. Significance: This study defines MetAP2 as an early-risk stratifier for molecular imaging of aggressive prostate cancer and describes a MetAP2-activated self-assembly small-molecule PET tracer for imaging MetAP2 activity in vivo.

Prostate cancer is responsible for over 30,000 US deaths annually, attributed largely to incurable metastatic disease. Here, we demonstrate that high levels of plectin are associated with localized and metastatic human prostate cancer when compared to benign prostate tissues. Knock-down of plectin inhibits prostate cancer cell growth and colony formation in vitro, and growth of prostate cancer xenografts in vivo. Plectin knock-down further impairs aggressive and invasive cellular behavior assessed by migration, invasion, and wound healing in vitro. Consistently, plectin knock-down cells have impaired metastatic colonization to distant sites including liver, lung, kidney, bone, and genitourinary system. Plectin knock-down inhibited number of metastases per organ, as well as decreased overall metastatic burden. To gain insights into the role of plectin in prostate cancer growth and metastasis, we performed proteomic analysis of prostate cancer plectin knock-down xenograft tissues. Gene set enrichment analysis shows an increase in levels of proteins involved with extracellular matrix and laminin interactions, and a decrease in levels of proteins regulating amino acid metabolism, cytoskeletal proteins, and cellular response to stress. Collectively these findings demonstrate that plectin is an important regulator of prostate cancer cell growth and metastasis.

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer that rarely develops de novo in primary tumors and is commonly acquired during the development of treatment resistance. NEPC is characterized by gain of neuroendocrine markers and loss of androgen receptor (AR), making it resistant to current therapeutic strategies targeting the AR signaling axis. Here, we report that MCM2, MCM3, MCM4, and MCM6 (MCM2/3/4/6) are elevated in human NEPC and high levels of MCM2/3/4/6 are associated with liver metastasis and poor survival in prostate cancer patients. MCM2/3/4/6 are four out of six proteins that form a core DNA helicase (MCM2-7) responsible for unwinding DNA forks during DNA replication. Inhibition of MCM2-7 by treatment with ciprofloxacin inhibits NEPC cell proliferation and migration in vitro, significantly delays NEPC tumor xenograft growth, and partially reverses the neuroendocrine phenotype in vivo. Our study reveals the clinical relevance of MCM2/3/4/6 proteins in NEPC and suggests that inhibition of MCM2-7 may represent a new therapeutic strategy for NEPC.

Suction applied at the base of a square-back Ahmed body is shown to create a global effect on the wake, reducing the recirculating bubble length and increasing the base drag. Weak suction causes a small shortening of the bubble and intensifies the steady reflectional symmetry breaking (RSB) mode present in the horizontal direction. Stronger suction significantly suppresses the RSB mode, indicating that the steady asymmetric instability does not bear a highly curved bubble. The stabilized wake experiences very low frequency oscillations in the horizontal direction together with a well synchronized shedding mode in the vertical direction.

Prostate cancer remains the most common non-cutaneous malignancy among men in the United States. To discover potential serum-based biomarkers for high-risk prostate cancer, we performed a high-multiplex immunoassay utilizing patient-matched pre-operative and post-operative serum samples from ten men with high-grade and high-volume prostate cancer. Our study identified six (CASP8, MSLN, FGFBP1, ICOSLG, TIE2 and S100A4) out of 174 proteins that were significantly decreased after radical prostatectomy. High levels of CASP8 were detected in pre-operative serum samples when compared to post-operative serum samples and serum samples from patients with benign prostate hyperplasia (BPH). By immunohistochemistry, CASP8 protein was expressed at higher levels in prostate cancer tissues compared to non-cancerous and BPH tissues. Likewise, CASP8 mRNA expression was significantly upregulated in prostate cancer when compared to benign prostate tissues in four independent clinical datasets. In addition, mRNA levels of CASP8 were higher in patients with recurrent prostate cancer when compared to patients with non-recurrent prostate cancer and high expression of CASP8 was associated with worse disease-free survival and overall survival in renal cancer. Together, our results suggest that CASP8 may potentially serve as a biomarker for high-risk prostate cancer and possibly renal cancer.

Prostate cancer remains among the leading causes of cancer-related deaths in men. Patients with aggressive disease typically undergo hormone deprivation therapy. Although treatment is initially very successful, these men commonly progress to lethal, castration-resistant prostate cancer (CRPC) in 2 to 3 years. Standard therapies for CRPC include second-generation antiandrogens, which prolong patient lifespan by only several months. It is imperative to advance our understanding of the mechanisms leading to resistance to identify new therapies for aggressive prostate cancer. This study identifies Notch1 as a therapeutic target in prostate cancer. Loss of NOTCH1 in aggressive prostate cancer cells decreases proliferation, invasion, and tumorsphere formation. Therapeutic inhibition of Notch1 activity with gamma secretase inhibitors RO4929097 or DAPT in prostate cancer cells further results in decreased proliferative abilities. Loss of NOTCH1 and treatment of immunocompromised mice bearing prostate cancer xenografts with RO4929097 display significantly impaired tumor growth. Loss of NOTCH1 additionally decreased metastatic potential of prostate cancer cells in invasion assays in vitro as well as in vivo experiments. Moreover, treatment with gamma secretase inhibitors or NOTCH1 gene deletion synergized with antiandrogen therapies, enzalutamide or abiraterone, to decrease the growth of prostate cancer cells. Combination of gamma secretase inhibitors with abiraterone significantly inhibited cell migration and invasion, while combination with enzalutamide reversed enzalutamide-induced migration and invasion. These collective findings suggest loss of NOTCH1 delays growth of CRPC and inhibits metastasis, and inhibition of Notch1 activation in conjunction with second-generation antiandrogen therapies could delay growth and progression of prostate cancer.

Breast cancer remains the second most lethal cancer among women in the United States and triple-negative breast cancer is the most aggressive subtype with limited treatment options. Trop2, a cell membrane glycoprotein, is overexpressed in almost all epithelial cancers. In this study, we demonstrate that Trop2 is overexpressed in triple-negative breast cancer (TNBC), and downregulation of Trop2 delays TNBC cell and tumor growth supporting the oncogenic role of Trop2 in breast cancer. Through proteomic profiling, we discovered a metabolic signature comprised of TALDO1, GPI, LDHA, SHMT2, and ADK proteins that were downregulated in Trop2-depleted breast cancer tumors. The identified oncogene-mediated metabolic gene signature is significantly upregulated in TNBC patients across multiple RNA-expression clinical datasets. Our study further reveals that the metabolic gene signature reliably predicts poor survival of breast cancer patients with early stages of the disease. Taken together, our study identified a new five-gene metabolic signature as an accurate predictor of breast cancer outcome.

Among men, prostate cancer is the second leading cause of cancer-associated mortality, with advanced disease remaining a major clinical challenge. We describe a small molecule, SU086, as a new therapeutic strategy for advanced prostate cancer. We demonstrate that SU086 inhibits the growth of prostate cancer cells in vitro, cell line and patient-derived xenografts in vivo, and ex vivo prostate cancer patient specimens. Furthermore, SU086 in combination with standard of care second-generation anti-androgen therapies displayed increased impairment of prostate cancer cell and tumor growth in vitro and in vivo. Cellular thermal shift assay (CETSA) revealed that SU086 binds to heat shock protein 90 (HSP90) and leads to a decrease in HSP90 levels. Proteomic and metabolomic profiling further revealed that the SU086 decreases HSP90 and leads to perturbation of glycolysis. Our study identifies SU086 as a new treatment for advanced prostate cancer as a single agent or when combined with second-generation anti-androgens.

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) holds great promise for deep tissue visualization. Development of novel clinical translatable NIR-II probes is crucial for realizing the medical applications of NIR-II fluorescence imaging. Herein, the glutathione-capped gold nanoclusters (AuNCs, specifically Au25 (SG)18 ) demonstrate highly efficient binding capability to hydroxyapatite in vitro for the first time. Further in vivo NIR-II fluorescence imaging of AuNCs indicate that they accumulate in bone tissues with high contrast and signal-background ratio. AuNCs are also mainly and quickly excreted from body through renal system, showing excellent ribs and thoracic vertebra imaging because of no background signal in liver and spleen. The deep tissue penetration capability and high resolution of AuNCs in NIR-II imaging render their great potential for fluorescence-guided surgery like spinal pedicle screw implantation. Overall, AuNCs are highly promising and clinical translatable NIR-II imaging probe for visualizing bone and bone related abnormalities.

Here, we report a novel non-epigenetic function of histone deacetylase (HDAC) 8 in activating cancer stem cell (CSC)-like properties in breast cancer cells by enhancing the stability of Notch1 protein. The pan-HDAC inhibitors AR-42 and SAHA, and the class I HDAC inhibitor depsipeptide, suppressed mammosphere formation and other CSC markers by reducing Notch1 expression in MDA-MB-231 and SUM-159 cells. Interrogation of individual class I isoforms (HDAC1–3 and 8) using si/shRNA-mediated knockdown, ectopic expression and/or pharmacological inhibition revealed HDAC8 to be the primary mediator of this drug effect. This suppression of Notch1 in response to HDAC8 inhibition was abrogated by the proteasome inhibitor MG132 and siRNA-induced silencing of Fbwx7, indicating Notch1 suppression occurred through proteasomal degradation. However, co-immunoprecipitation analysis indicated that HDAC8 did not form complexes with Notch1 and HDAC inhibition had no effect on Notch1 acetylation. In a xenograft tumor model, the tumorigenicity of breast cancer cells was decreased by HDAC8 knockdown. These findings suggest the therapeutic potential of HDAC8 inhibition to suppress Notch1 signaling in breast cancer.

Introduction and Objectives: Breast cancer remains the second most lethal cancer among women in the US, with triple negative breast cancer (TNBC) as the most aggressive subtype with limited treatment options. Trop2, a cell membrane glycoprotein, is overexpressed nearly all epithelial cancers including triple negative breast cancer. In this study, we demonstrate that loss of Trop2 derives downregulation of metabolic genes. Trop2 oncogene-driven metabolic gene signature is highly elevated in breast cancer patients and predicts poor outcome. Methods: Trop2 expression levels in two independent patient cohorts were analyzed with immunohistochemistry. Trop2 was knockdown in TNBC cell line HCC1806 with shRNA and knock-out in HCC1806 with CRISPR Cas9 system. Trop2 downregulation or gene deletion effect was tested in vitro with colony formation and 3D Matrigel invasion assays. The effect of Trop2 downregulation in tumorigenesis was evaluated in vivo by subcutaneous implantation of control and Trop2 knockdown xenografts. Proteomic changes were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Trop2 led to downregulation of TALDO1 associated metabolic cluster genes which expression levels were further investigated in four independent breast cancer cohort. Finally, the correlation of Trop2 oncogene-driven metabolic gene signature with breast cancer outcome was analyzed in 13 independent breast cancer patient datasets. Results: We demonstrate Trop2 is overexpressed in TNBC, and downregulation of Trop2 disrupts TNBC cell and tumor growth. Through whole proteomic profiling, we discovered a novel metabolic cluster that was downregulated in Trop2-depleted breast cancer tumors. The identified oncogene-driven metabolic gene signature is significantly upregulated in TNBC patients across multiple clinical datasets. Our study further reveals that the metabolic gene signature reliably predicts poor survival of breast cancer patients with early stage of the disease. Conclusion: Our study identifies a new five gene metabolic oncogene-driven signature as a prognostic predictor of breast cancer. Citation Format: Merve Aslan, En-Chi Hsu, Fernando J. Garcia Marques, Abel Bermudez, Michelle Shen, Meghan A. Rice, Shiqin Liu, Robert West, Sharon J. Pitteri, Balázs Győrffy, Tanya Stoyanova. A novel oncogene mediated metabolic gene signature predicts breast cancer outcome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2324.

Background: The first line of treatment for men with advanced prostate cancer is androgen deprivation therapy. Although initial responses are observed, prostate cancer commonly relapses in its lethal metastatic form referred to as castration resistant prostate cancer (CRPC) with 1-2 years mean survival time. Neuroendocrine prostate cancer (NEPC) is highly aggressive, AR independent subtype and usually emerges post castration resistance. We recently identified that the cell surface receptor, Trop2, is a new driver of NEPC. Moreover, we demonstrated that Trop2 regulates prostate cancer growth and metastasis. In this study, we set out to delineate the molecular mechanisms through which Trop2 regulates prostate cancer growth and metastasis. Methods: Proximity-dependent Biotin Identification (BioID) followed by mass spectrometry was performed to identify Trop2 interactome. Lentiviral infection was used to generate prostate cancer cell lines with over-expression of Trop2 and knock-down of NOTCH1, SLC4A7, PLEC, and OCLN shRNA to modulate gene expression levels. In vitro functional assays were performed including colony formation, and Matrigel drop 3D cell invasion assays. Results: The Trop2 membrane interactome was identified utilizing Proximity-dependent Biotin Identification (BioID) in living cells and uncovered that Trop2-mediated prostate cancer growth and metastasis are orchestrated by distinct downstream pathways including Notch signaling (NOTCH1), control of intracellular pH (SLC4A7), exosome secretion (PLEC), and tight junctions (OCLN). Interaction of Trop2 binding partners including NOTCH1, SLC4A7, PLEC and OCLN with Trop2 were further validated by fluorescence resonance energy transfer (FRET) using confocal microscopy. Moreover, knocking down the Trop2 interacting partners in Trop2 over-expressing prostate cancer cells suppressed Trop2-driven growth and invasion ability. Conclusions: In a previous study, we identified cell surface receptor, Trop2, as a novel driver of metastatic NEPC. Herein, our new findings reveal that Trop2 interacts with NOTCH1, SLC4A7, PLEC, and OCLN, which may highlight novel biological functions of Trop2 in prostate tumorigenesis and provide new understanding of the potential mechanism of neuroendocrine differentiation and metastasis to provide new therapeutic strategy for metastatic CRPC with neuroendocrine features. Citation Format: Tanya Ivanova Stoyanova, En-Chi Hsu, Shiqin Liu, Fernando Jose Garcia Marques, Abel Bermudez, Merve Aslan, Michelle Shen, Sharon Pitteri, James D. Brooks. Trop2 regulates prostate cancer growth and metastasis through distinct molecular mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 81.

Activation of metastatic reprogramming is critical for tumour metastasis. However, more detailed knowledge of the underlying mechanism is needed to enable targeted intervention. Here, we show that paraspeckle component 1 (PSPC1), identified in an aberrant 13q12.11 locus, is upregulated and associated with poor survival in patients with cancer. PSPC1 promotes tumorigenesis, epithelial-to-mesenchymal transition (EMT), stemness and metastasis in multiple cell types and in spontaneous mouse cancer models. PSPC1 is the master activator for transcription factors of EMT and stemness and accompanies c-Myc activation to facilitate tumour growth. PSPC1 increases transforming growth factor-β1 (TGF-β1) secretion through an interaction with phosphorylated and nuclear Smad2/3 to potentiate TGF-β1 autocrine signalling. Moreover, PSPC1 acts as a contextual determinant of the TGF-β1 pro-metastatic switch to alter Smad2/3 binding preference from tumour-suppressor to pro-metastatic genes. Having validated the PSPC1-Smads-TGF-β1 axis in various cancers, we conclude that PSPC1 is a master activator of pro-metastatic switches and a potential target for anti-metastasis drugs.

Substantial evidence has clearly demonstrated the role of the IL-6-NF-κB signaling loop in promoting aggressive phenotypes in breast cancer. However, the exact mechanism by which this inflammatory loop is regulated remains to be defined. Here, we report that integrin-linked kinase (ILK) acts as a molecular switch for this feedback loop. Specifically, we show that IL-6 induces ILK expression via E2F1 upregulation, which, in turn, activates NF-κB signaling to facilitate IL-6 production. shRNA-mediated knockdown or pharmacological inhibition of ILK disrupted this IL-6-NF-κB signaling loop, and blocked IL-6-induced cancer stem cells in vitro and estrogen-independent tumor growth in vivo Together, these findings establish ILK as an intermediary effector of the IL-6-NF-κB feedback loop and a promising therapeutic target for breast cancer.

Infection of human hepatitis B virus (HBV) causes acute hepatitis. Its persistent infection leads to a high risk of developing chronic hepatitis, cirrhosis and hepatocellular carcinoma. The levels of HBV 3.5 kb and 2.4/2.1 kb RNAs transcribed from a replicating HBV expression plasmid in human hepatoma HuH-7 cells are repressed by tumour necrosis factor alpha treatment or overexpressed p65 in a dose-dependent manner. The diminished expression of endogenous p65 by a p65-specific siRNA or IkappaB-alpha overexpression enhances the HBV gene expression. The protein bound to the Specificity protein 1 (Sp1) binding sites (nt 1733-1753) of HBV core promoter is reduced by either tumour necrosis factor alpha treatment or overexpressed p65. The N-terminal 43-amino-acid region of p65, which is required to interact with Sp1, is essential to repress the Sp1-mediated transactivation. The binding of Sp1 to Sp1 site and the Sp1-dependent reporter expression are inhibited by p65 in a dose-dependent manner. Furthermore, nuclear factor-kappa B-mediated repression of HBV gene expression is abolished by deletion of Sp1 sites of HBV gene promoter. Together, these results demonstrate that nuclear factor-kappa B represses the HBV gene expression through its interaction with Sp1 and repression of Sp1-mediated transcriptional activation.

Here, we report a novel non-epigenetic function of histone deacetylase (HDAC) 8 in activating cancer stem cell (CSC)-like properties in breast cancer cells by enhancing the stability of Notch1 protein. The pan-HDAC inhibitors AR-42 and SAHA, and the class I HDAC inhibitor depsipeptide, suppressed mammosphere formation and other CSC markers by reducing Notch1 expression in MDA-MB-231 and SUM-159 cells. Interrogation of individual class I isoforms (HDAC1-3 and 8) using si/shRNA-mediated knockdown, ectopic expression and/or pharmacological inhibition revealed HDAC8 to be the primary mediator of this drug effect. This suppression of Notch1 in response to HDAC8 inhibition was abrogated by the proteasome inhibitor MG132 and siRNA-induced silencing of Fbwx7, indicating Notch1 suppression occurred through proteasomal degradation. However, co-immunoprecipitation analysis indicated that HDAC8 did not form complexes with Notch1 and HDAC inhibition had no effect on Notch1 acetylation. In a xenograft tumor model, the tumorigenicity of breast cancer cells was decreased by HDAC8 knockdown. These findings suggest the therapeutic potential of HDAC8 inhibition to suppress Notch1 signaling in breast cancer.

Metastatic castration-resistant prostate cancer (CRPC) is the primary cause of prostate cancer specific mortality, and is currently incurable. Defining new mechanisms that can predict progression and drive lethal CRPC is critical. Notch1 receptor, a cell surface-signaling molecule dysregulated in many cancers, is highly expressed in CRPC. Chronic activation of Notch1 synergizes with multiple oncogenic pathways altered in early disease to promote the development of poorly differentiated prostate carcinoma. Consistent with its activation in clinical CRPC, tumors driven by NICD1 in combination with alternative pathways altered in prostate cancer are metastatic and resistant to androgen deprivation. Genetic and pharmacological inhibition of Notch1 activity decreases cell proliferation and colony formation of 22RV1 prostate cancer cells in vitro. 22RV1 subcutaneous xenograft growth was significantly impaired by treatment with pharmacological inhibitors of Notch1 activation over the course of 20-day treatment. Further, Notch1 inhibition in combination with other standard prostate cancer treatments compounded efficacy of individual treatments to attenuate colony formation potential of prostate cancer cells in vitro. The Notch1 signaling axis, confirmed to synergize with multiple pathways to promote metastatic CRPC already provides a novel pathway for diagnostic stratification of prostate cancer patients. Our studies additionally implicate Notch1 as a therapeutically relevant target for aggressive prostate cancer. Citation Format: Meghan A. Rice, En-Chi Hsu, Tanya Stoyanova. Therapeutic inhibition of Notch1 in metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4917. doi:10.1158/1538-7445.AM2017-4917

BACKGROUND Cancer cachexia is a debilitating condition that impacts patient morbidity, mortality, and quality of life and for which effective therapies are lacking. The anticachectic activity of the novel HDAC inhibitor AR-42 was investigated in murine models of cancer cachexia. METHODS The effects of AR-42 on classic features of cachexia were evaluated in the C-26 colon adenocarcinoma and Lewis lung carcinoma (LLC) models. Effects on survival in comparison with approved HDAC inhibitors (vorinostat, romidepsin) were determined. The muscle metabolome and transcriptome (by RNA-seq), as well as serum cytokine profile, were evaluated. Data were analyzed using mixed effects models, analysis of variance, or log-rank tests. All statistical tests were two-sided. RESULTS In the C-26 model, orally administered AR-42 preserved body weight (23.9±2.6 grams, AR-42-treated; 20.8±1.3 grams, vehicle-treated; P = .005), prolonged survival (P < .001), prevented reductions in muscle and adipose tissue mass, muscle fiber size, and muscle strength and restored intramuscular mRNA expression of the E3 ligases MuRF1 and Atrogin-1 to basal levels (n = 8). This anticachectic effect, confirmed in the LLC model, was not observed after treatment with vorinostat and romidepsin. AR-42 suppressed tumor-induced changes in inflammatory cytokine production and multiple procachexia drivers (IL-6, IL-6Rα, leukemia inhibitory factor, Foxo1, Atrogin-1, MuRF1, adipose triglyceride lipase, uncoupling protein 3, and myocyte enhancer factor 2c). Metabolomic analysis revealed cachexia-associated changes in glycolysis, glycogen synthesis, and protein degradation in muscle, which were restored by AR-42 to a state characteristic of tumor-free mice. CONCLUSIONS These findings support further investigation of AR-42 as part of a comprehensive therapeutic strategy for cancer cachexia.

Recurrent cancer genome aberrations are indicators of residing crucial cancer genes. Although recent advances in genomic technologies have led to a global view of cancer genome aberrations, the identification of target genes and biomarkers from the aberrant loci remains difficult. To facilitate searches of cancer genes in human hepatocellular carcinoma (HCC), we established a comprehensive protocol to analyze copy number alterations (CNAs) in cancer genomes using high-density single nucleotide polymorphism arrays with unpaired reference genomes. We identified common HCC genes by overlapping the shared aberrant loci in multiple cell lines with functional validation and clinical implications. A total of 653 amplicons and 57 homozygous deletions (HDs) were revealed in 23 cell lines. To search for novel HCC genes, we overlapped aberrant loci to uncover 6 HDs and 126 amplicons shared by at least two cell lines. We selected two novel genes, fibronectin type III domain containing 3B (FNDC3B) at the 3q26.3 overlapped amplicon and solute carrier family 29 member 2 (SLC29A2) at the 11q13.2 overlapped amplicon, to investigate their aberrations in HCC tumorigenesis. Aberrant up-regulation of FNDC3B and SLC29A2 occurred in multiple HCC data sets. Knockdown of these genes in amplified cells decreased cell proliferation, anchorage-independent growth, and tumor formation in xenograft models. Importantly, up-regulation of SLC29A2 in HCC tissues was significantly associated with advanced stages (P = 0.0031), vascular invasion (P = 0.0353), and poor patient survival (P = 0.0325). Overexpression of FNDC3B or SLC29A2 in unamplified HCC cells promoted cell proliferation through activation of the signal transducer and activator of transcription 3 signaling pathway. Conclusion: A standardized genome-wide CNA analysis protocol using data from user-generated or public domains normalized with unpaired reference genomes has been established to facilitate high-throughput detection of cancer genes as significant target genes and biomarkers for cancer diagnosis and therapy. (HEPATOLOGY 2010)

Protein-tyrosine phosphatase PTPN3 is a membrane-associated non-receptor protein-tyrosine phosphatase. PTPN3 contains a N-terminal FERM domain, a middle PDZ domain, and a C-terminal phosphatase domain. Upon co-expression of PTPN3, the level of human hepatitis B viral (HBV) RNAs, 3.5 kb, 2.4/2.1 kb, and 0.7 kb transcribed from a replicating HBV expression plasmid is significantly reduced in human hepatoma HuH-7 cells. When the expression of endogenous PTPN3 protein is diminished by specific small interfering RNA, the expression of HBV genes is enhanced, indicating that the endogenous PTPN3 indeed plays a suppressive role on HBV gene expression. PTPN3 can interact with HBV core protein. The interaction is mediated via the PDZ domain of PTPN3 and the carboxyl-terminal last four amino acids of core. Either deletion of PDZ domain of PTPN3 or substitution of PDZ ligand in core has no effect on PTPN3-mediated suppression. These results clearly show that the interaction of PTPN3 with core is not required for PTPN3 suppressive effect. Mutation of (359)serine and (835)serine of 14-3-3beta binding sites to alanine, which slightly reduces the interaction with 14-3-3beta, does not influence the PTPN3 effect. In contrast, mutation of the invariant (842)cysteine residue in phosphatase domain to serine, which makes the phosphatase activity inactive, does not change its subcellular localization and interaction with core or 14-3-3beta, but completely abolishes PTPN3-mediated suppression. Furthermore, deletion of FERM domain does not affect the phosphatase activity or interaction with 14-3-3beta, but changes the subcellular localization from cytoskeleton-membrane interface to cytoplasm and nucleus, abolishes binding to core, and diminishes the PTPN3 effect on HBV gene expression. Taken together, these results demonstrate that the phosphatase activity and FERM domain of PTPN3 are essential for its suppression of HBV gene expression.

Objectives of the study: Integrin-linked kinase (ILK) is an intracellular adaptor and kinase that links the cell adhesion receptors, integrins and growth factors to the actin cytoskeleton and is a component of multiple signaling pathways. Recent studies have demonstrated that ILK is highly expressed in various cancers, and that inhibition of ILK expression and activity may serve as an attractive strategy for cancer therapy. An important substrate of ILK is protein kinase B (PKB)/Akt, which ILK phosphorylates at the S473 site, thereby contributing to its activation. The objective of our work is to develop a novel potent small molecule inhibitor of ILK. Methodology: Previously, we developed AR12 (formerly OSU-03012), a novel celecoxib-derived inhibitor of phosphoinositide-dependent protein kinase-1 (PDK1) that downregulates PKB/Akt phosphorylation at T308 (known as the PDK1 site) and induces apoptosis and growth inhibition in cancer cells by blocking the PI3K/Akt pathway. However, to become fully activated, PKB/Akt requires both phosphorylation at two sites_T308/S473. Using OSU-03012 as a lead, we synthesized a series of derivatives to generate a small kinase inhibitor library, which was screened for compounds that could specifically downregulate PKB/Akt phosphorylation at S473, which is known as the PDK2 target site. The MTT assay was used to examine cancer cell viability after drug treatment. A radiometric ILK kinase assay was used to assess the ILK kinase inhibitory activities of the compounds. Cellular protein levels and phosphorylation status of ILK downstream targets were determined in drug-treated cells by western blot analysis. Results & Conclusions: The screening of our focused AR12-derived kinase inhibitor library identified T315 as an efficient inhibitor of PKB/Akt phosphorylation at S473 without altering phosphorylation at the T308 site. Moreover, T315 demonstrated strong cytotoxicity against prostate cancer cell lines (PC-3 and LNCaP cells; IC50, 2.0 and 1.8 μM, respectively), but not primary nonmalignant prostate epithelial cells. To date, the phosphorylation of PKB/Akt at its PDK2 site has been attributed to at least ten candidate kinases, including PKCα/βII, mTORC2, ILK, and ATM. After examination of several signaling pathways by western blotting, two downstream signaling effectors of ILK, GSK-3β and MLC2, were shown to be downregulated by T315 in a dose-dependent manner, while downstream targets of mTORC2, another PDK2 candidate, were unchanged by T315 treatment. Importantly, T315 also dose-dependently inhibited ILK kinase activity (IC50 < 1 μM) as determined by radiometric kinase assay. Together, these findings indicate that T315 is a putative ILK inhibitor. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1360. doi:10.1158/1538-7445.AM2011-1360