Co-axial hydrogel spinning for facile biofabrication of prostate cancer-like 3D models

Glandular cancers are amongst the most prevalent types of cancer, which can develop in many different organs, presenting challenges in their detection as well as high treatment variability and failure rates. For that purpose, anticancer drugs are commonly tested in cancer cell lines grown in 2D tissue culture on plastic dishesin vitro, or in animal modelsin vivo. However, 2D culture models diverge significantly from the 3D characteristics of living tissues and animal models require extensive animal use and time. Glandular cancers, such as prostate cancer-the second leading cause of male cancer death-typically exist in co-centrical architectures where a cell layer surrounds an acellular lumen. Herein, this spatial cellular position and 3D architecture, containing dual compartments with different hydrogel materials, is engineered using a simple co-axial nozzle setup, in a single step utilizing prostate as a model of glandular cancer. The resulting hydrogel soft structures support viable prostate cancer cells of different cell lines and enable over-time maturation into cancer-mimicking aggregates surrounding the acellular core. The biofabricated cancer mimicking structures are then used as a model to predict the inhibitory efficacy of the poly ADP ribose polymerase inhibitor, Talazoparib, and the antiandrogen drug, Enzalutamide, in the growth of the cancer cell layer. Our results show that the obtained hydrogel constructs can be adapted to quickly obtain 3D cancer models which combine 3D physiological architectures with high-throughput screening to detect and optimize anti-cancer drugs in prostate and potentially other glandular cancer types.

UCHL1 is a potential molecular indicator and therapeutic target for neuroendocrine carcinomas

Neuroendocrine carcinomas, such as neuroendocrine prostate cancer and small-cell lung cancer, commonly have a poor prognosis and limited therapeutic options. We report that ubiquitin carboxy-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme, is elevated in tissues and plasma from patients with neuroendocrine carcinomas. Loss of UCHL1 decreases tumor growth and inhibits metastasis of these malignancies. UCHL1 maintains neuroendocrine differentiation and promotes cancer progression by regulating nucleoporin, POM121, and p53. UCHL1 binds, deubiquitinates, and stabilizes POM121 to regulate POM121-associated nuclear transport of E2F1 and c-MYC. Treatment with the UCHL1 inhibitor LDN-57444 slows tumor growth and metastasis across neuroendocrine carcinomas. The combination of UCHL1 inhibitors with cisplatin, the standard of care used for neuroendocrine carcinomas, significantly delays tumor growth in pre-clinical settings. Our study reveals mechanisms of UCHL1 function in regulating the progression of neuroendocrine carcinomas and identifies UCHL1 as a therapeutic target and potential molecular indicator for diagnosing and monitoring treatment responses in these malignancies.

High expression of Trop2 is associated with aggressive localized prostate cancer and is a candidate urinary biomarker

Distinguishing indolent from clinically significant localized prostate cancer is a major clinical challenge and influences clinical decision-making between treatment and active surveillance. The development of novel predictive biomarkers will help with risk stratification, and clinical decision-making, leading to a decrease in over or under-treatment of patients with prostate cancer. Here, we report that Trop2 is a prognostic tissue biomarker for clinically significant prostate cancer by utilizing the Canary Prostate Cancer Tissue Microarray (CPCTA) cohort composed of over 1100 patients from a multi-institutional study. We demonstrate that elevated Trop2 expression is correlated with worse clinical features including Gleason score, age, and pre-operative PSA levels. More importantly, we demonstrate that elevated Trop2 expression at radical prostatectomy predicts worse overall survival in men undergoing radical prostatectomy. Additionally, we detect shed Trop2 in urine from men with clinically significant prostate cancer. Our study identifies Trop2 as a novel tissue prognostic biomarker and a candidate non-invasive marker for prostate cancer.

Dual-inhibitory domain iCARs improve the efficiency of the AND-NOT gate CAR T strategy

CAR (chimeric antigen receptor) T cell therapy has shown clinical success in treating hematological malignancies, but its treatment of solid tumors has been limited. One major challenge is on-target, off-tumor toxicity, where CAR T cells also damage normal tissues that express the targeted antigen. To reduce this detrimental side-effect, Boolean-logic gates like AND-NOT gates have utilized an inhibitory CAR (iCAR) to specifically curb CAR T cell activity at selected nonmalignant tissue sites. However, the strategy seems inefficient, requiring high levels of iCAR and its target antigen for inhibition. Using a TROP2-targeting iCAR with a single PD1 inhibitory domain to inhibit a CEACAM5-targeting CAR (CEACAR), we observed that the inefficiency was due to a kinetic delay in iCAR inhibition of cytotoxicity. To improve iCAR efficiency, we modified three features of the iCAR-the avidity, the affinity, and the intracellular signaling domains. Increasing the avidity but not the affinity of the iCAR led to significant reductions in the delay. iCARs containing twelve different inhibitory signaling domains were screened for improved inhibition, and three domains (BTLA, LAIR-1, and SIGLEC-9) each suppressed CAR T function but did not enhance inhibitory kinetics. When inhibitory domains of LAIR-1 or SIGLEC-9 were combined with PD-1 into a single dual-inhibitory domain iCAR (DiCARs) and tested with the CEACAR, inhibition efficiency improved as evidenced by a significant reduction in the inhibitory delay. These data indicate that a delicate balance between CAR and iCAR signaling strength and kinetics must be achieved to regulate AND-NOT gate CAR T cell selectivity.

ACAA2 is a novel molecular indicator for cancers with neuroendocrine phenotype

BACKGROUND

Neuroendocrine phenotype is commonly associated with therapy resistance and poor prognoses in small-cell neuroendocrine cancers (SCNCs), such as neuroendocrine prostate cancer (NEPC) and small-cell lung cancer (SCLC). Expression levels of current neuroendocrine markers exhibit high case-by-case variability, so multiple markers are used in combination to identify SCNCs. Here, we report that ACAA2 is elevated in SCNCs and is a potential molecular indicator for SCNCs.

METHODS

ACAA2 expressions in tumour xenografts, tissue microarrays (TMAs), and patient tissues from prostate and lung cancers were analysed via immunohistochemistry. ACAA2 mRNA levels in lung and prostate cancer (PC) patients were assessed in published datasets.

RESULTS

ACAA2 protein and mRNA levels were elevated in SCNCs relative to non-SCNCs. Medium/high ACAA2 intensity was observed in 78% of NEPC PDXs samples (N = 27) relative to 33% of adeno-CRPC (N = 86), 2% of localised PC (N = 50), and 0% of benign prostate specimens (N = 101). ACAA2 was also elevated in lung cancer patient tissues with neuroendocrine phenotype. 83% of lung carcinoid tissues (N = 12) and 90% of SCLC tissues (N = 10) exhibited medium/high intensity relative to 40% of lung adenocarcinoma (N = 15).

CONCLUSION

ACAA2 expression is elevated in aggressive SCNCs such as NEPC and SCLC, suggesting it is a potential molecular indicator for SCNCs.

Aggregation induced nucleic acids recognition by homodimeric asymmetric monomethyne cyanine fluorochromes in mesenchymal stem cells

In the light of recent retrovirus pandemics, the issue of discovering new and diverse RNA-specific fluorochromes for research and diagnostics became of acute importance. The great majority of nucleic acid-specific probes either do not stain RNA or cannot distinguish between DNA and RNA. The versatility of polymethine dyes makes them suitable as stains for visualization, analysis, and detection of nucleic acids, proteins, and other biomolecules. We synthesized the asymmetric dicationic homodimeric monomethine cyanine dyes 1,1'-(1,3-phenylenebis(methylene))bis(4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)pyridin-1-ium) bromide (Т1) and 1,1'-(1,3-phenylenebis(methylene))bis(4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium) bromide (M1) and tested their binding specificity, spectral characteristics, membrane penetration in living and fixed cells, cellular toxicity, and stability of fluorescent emission. Mesenchymal cells have diverse phenotypes and extensive proliferation and differentiation properties. We found dyes T1 and M1 to show high photochemical stability in living mesenchymal stem cells from apical papilla (SCAP) with a strong fluorescent signal when bound to nucleic acids. We found M1 to perform better than control fluorochrome (Hoechst 33342) for in vivo DNA visualization. T1, on the other hand, stains granular cellular structures resembling ribosomes in living cells and after permeabilization of the nuclear membrane stains the nucleoli and not the chromatin in the nucleus. This makes T1 suitable for the visualization of structures rich in RNA in living and fixed cells.

Proteomics analysis of urine and catheter-associated biofilms in spinal cord injury patients

After spinal cord injury (SCI), use chronic urinary catheters for bladder management is common, making these patients especially vulnerable to catheter-associated complications. Chronic catheterization is associated with bacterial colonization and frequent catheter-associated urinary tract infections (CAUTI). One determinant of infection success and treatment resistance is production of catheter-associated biofilms, composed of microorganisms and host- and microbial-derived components. To better understand the biofilm microenvironment, we performed proteomics analysis of catheter-associated biofilms and paired urine samples from four people with SCI with chronic indwelling urinary catheters. We developed a novel method for the removal of adhered cellular components on catheters that contained both human and microbial homologous proteins. Proteins from seven microbial species were identified including: Escherichia coli, Klebsiella species (spp), Enterococcus spp, Proteus mirabilis, Pseudomonas spp, Staphylococcus spp, and Candida spp. Peptides identified from catheter biofilms were assigned to 4,820 unique proteins, with 61% of proteins assigned to the biofilm-associated microorganisms, while the remainder were human-derived. Contrastingly, in urine, only 51% were assigned to biofilm-associated microorganisms and 4,554 proteins were identified as a human-derived. Of the proteins assigned to microorganisms in the biofilm and paired urine, Enterococcus, Candida spp, and P. mirabilis had greater associations with the biofilm phase, whereas E. coli and Klebsiella had greater associations with the urine phase, thus demonstrating a significant difference between the urine and adhered microbial communities. The microbial proteins that differed significantly between the biofilm and paired urine samples mapped to pathways associated with amino acid synthesis, likely related to adaptation to high urea concentrations in the urine, and growth and protein synthesis in bacteria in the biofilm. Human proteins demonstrated enrichment for immune response in the catheter-associated biofilm. Proteomic analysis of catheter-associated biofilms and paired urine samples has the potential to provide detailed information on host and bacterial responses to chronic indwelling urinary catheters and could be useful for understanding complications of chronic indwelling catheters including CAUTIs, urinary stones, and catheter blockages.

Multimodal In Vivo Tracking of Chimeric Antigen Receptor T Cells in Preclinical Glioblastoma Models

OBJECTIVES

Iron oxide nanoparticles have been used to track the accumulation of chimeric antigen receptor (CAR) T cells with magnetic resonance imaging (MRI). However, the only nanoparticle available for clinical applications to date, ferumoxytol, has caused rare but severe anaphylactic reactions. MegaPro nanoparticles (MegaPro-NPs) provide an improved safety profile. We evaluated whether MegaPro-NPs can be applied for in vivo tracking of CAR T cells in a mouse model of glioblastoma multiforme.

MATERIALS AND METHODS

We labeled tumor-targeted CD70CAR (8R-70CAR) T cells and non-tumor-targeted controls with MegaPro-NPs, followed by inductively coupled plasma optical emission spectroscopy, Prussian blue staining, and cell viability assays. Next, we treated 42 NRG mice bearing U87-MG/eGFP-fLuc glioblastoma multiforme xenografts with MegaPro-NP-labeled/unlabeled CAR T cells or labeled untargeted T cells and performed serial MRI, magnetic particle imaging, and histology studies. The Kruskal-Wallis test was conducted to evaluate overall group differences, and the Mann-Whitney U test was applied to compare the pairs of groups.

RESULTS

MegaPro-NP-labeled CAR T cells demonstrated significantly increased iron uptake compared with unlabeled controls ( P < 0.01). Cell viability, activation, and exhaustion markers were not significantly different between the 2 groups ( P > 0.05). In vivo, tumor T2* relaxation times were significantly lower after treatment with MegaPro-NP-labeled CAR T cells compared with untargeted T cells ( P < 0.01). There is no significant difference in tumor growth inhibition between mice injected with labeled and unlabeled CAR T cells.

CONCLUSIONS

MegaPro-NPs can be used for in vivo tracking of CAR T cells. Because MegaPro-NPs recently completed phase II clinical trial investigation as an MRI contrast agent, MegaPro-NP is expected to be applied to track CAR T cells in cancer immunotherapy trials in the near future.

Blood Plasma Calorimetric Profiles of Women with Preeclampsia: Effect of Oxidative Stress

Preeclampsia is a pregnancy-related disease with poor placentation and presents itself through hypertension and proteinuria. The disease is also associated with the oxidative modification of proteins in maternal blood plasma. In this work, we combine differential scanning calorimetry (DSC), capillary electrophoresis, and atomic force microscopy (AFM) to evaluate the changes in the plasma denaturation profiles of patients with preeclampsia (PE) as compared with those of pregnant controls. Our results demonstrate that the last trimester of pregnancy substantially affects the main calorimetric characteristics of blood plasma from pregnant controls relative to nonpregnant women. These variations correlate well with the changes in protein levels determined by electrophoresis. DSC analysis revealed significant deviations in the plasma heat capacity profiles of preeclamptic patients from those of pregnant controls. These alterations are expressed mainly in a substantial reduction in albumin-assigned transitions and an upward shift in its denaturation temperature, lower calorimetric enthalpy changes, and a reduced ratio of heat capacity in the albumin/globulin-assigned thermal transitions, which are more pronounced in severe PE cases. The in vitro oxidation model shows that the alteration of PE thermograms is partly related to protein oxidation. AFM data detected numerous aggregate formations in the plasma of PE samples and fewer small ones in the pregnant controls, which are not found in healthy nonpregnant samples. These findings could serve as a basis for further investigations to reveal the possible relationship between albumin thermal stabilization, the increased inflammatory state and oxidative stress, and protein misfolding in preeclampsia.

Membrane Lesions and Reduced Life Span of Red Blood Cells in Preeclampsia as Evidenced by Atomic Force Microscopy

Preeclampsia (PE) presents with maternal de novo hypertension and significant proteinuria and is one of the leading causes of maternal and perinatal morbidity and mortality with unknown etiology. The disease is associated with inflammatory vascular response and severe red blood cell (RBC) morphology changes. This study examined the nanoscopic morphological changes of RBCs from PE women versus normotensive healthy pregnant controls (PCs) and non-pregnant controls (NPCs) applying atomic force microscopy (AFM) imaging. The results revealed that the membrane of fresh PE RBCs differed significantly from healthy ones by the presence of invaginations and protrusions and an increased roughness value (R_rms) (4.7 ± 0.8 nm for PE vs. 3.8 ± 0.5 nm and 2.9 ± 0.4 nm for PCs and NPCs, respectively). PE-cells aging resulted in more pronounced protrusions and concavities, with exponentially increasing R_rms values, in contrast to the controls, where the R_rms parameter decreased linearly with time. The R_rms, evaluated on a 2 × 2 µm² scanned area, for senescent PE cells (13 ± 2.0 nm) was significantly higher (p < 0.01) than that of PCs (1.5 ± 0.2 nm) and NPCs (1.9 ± 0.2 nm). Furthermore, the RBCs from PE patients appeared fragile, and often only ghosts were observed instead of intact cells at 20-30 days of aging. Oxidative-stress simulation on healthy cells led to RBC membrane features similar to those observed for PE cells. The results demonstrate that the most pronounced effects on RBCs in PE patients are related to impaired membrane homogeneity and strongly altered roughness values, as well as to vesiculation and ghost formation in the course of cell aging.

Correlation of 68Ga-RM2 PET with Postsurgery Histopathology Findings in Patients with Newly Diagnosed Intermediate- or High-Risk Prostate Cancer

⁶⁸Ga-RM2 targets gastrin-releasing peptide receptors (GRPRs), which are overexpressed in prostate cancer (PC). Here, we compared preoperative ⁶⁸Ga-RM2 PET to postsurgery histopathology in patients with newly diagnosed intermediate- or high-risk PC. Methods: Forty-one men, 64.0 ± 6.7 y old, were prospectively enrolled. PET images were acquired 42-72 min (median ± SD, 52.5 ± 6.5 min) after injection of 118.4-247.9 MBq (median ± SD, 138.0 ± 22.2 MBq) of ⁶⁸Ga-RM2. PET findings were compared with preoperative multiparametric MRI (mpMRI) (n = 36) and ⁶⁸Ga-PSMA11 PET (n = 17) and correlated to postprostatectomy whole-mount histopathology (n = 32) and time to biochemical recurrence. Nine participants decided to undergo radiation therapy after study enrollment. Results: All participants had intermediate- (n = 17) or high-risk (n = 24) PC and were scheduled for prostatectomy. Prostate-specific antigen was 8.8 ± 77.4 (range, 2.5-504) and 7.6 ± 5.3 ng/mL (range, 2.5-28.0 ng/mL) when participants who ultimately underwent radiation treatment were excluded. Preoperative ⁶⁸Ga-RM2 PET identified 70 intraprostatic foci of uptake in 40 of 41 patients. Postprostatectomy histopathology was available in 32 patients in which ⁶⁸Ga-RM2 PET identified 50 of 54 intraprostatic lesions (detection rate = 93%). ⁶⁸Ga-RM2 uptake was recorded in 19 nonenlarged pelvic lymph nodes in 6 patients. Pathology confirmed lymph node metastases in 16 lesions, and follow-up imaging confirmed nodal metastases in 2 lesions. ⁶⁸Ga-PSMA11 and ⁶⁸Ga-RM2 PET identified 27 and 26 intraprostatic lesions, respectively, and 5 pelvic lymph nodes each in 17 patients. Concordance between ⁶⁸Ga-RM2 and ⁶⁸Ga-PSMA11 PET was found in 18 prostatic lesions in 11 patients and 4 lymph nodes in 2 patients. Noncongruent findings were observed in 6 patients (intraprostatic lesions in 4 patients and nodal lesions in 2 patients). Sensitivity and accuracy rates for ⁶⁸Ga-RM2 and ⁶⁸Ga-PSMA11 (98% and 89% for ⁶⁸Ga-RM2 and 95% and 89% for ⁶⁸Ga-PSMA11) were higher than those for mpMRI (77% and 77%, respectively). Specificity was highest for mpMRI with 75% followed by ⁶⁸Ga-PSMA11 (67%) and ⁶⁸Ga-RM2 (65%). Conclusion: ⁶⁸Ga-RM2 PET accurately detects intermediate- and high-risk primary PC, with a detection rate of 93%. In addition, ⁶⁸Ga-RM2 PET showed significantly higher specificity and accuracy than mpMRI and a performance similar to ⁶⁸Ga-PSMA11 PET. These findings need to be confirmed in larger studies to identify which patients will benefit from one or the other or both radiopharmaceuticals.

Molecular mechanisms underlying the development of neuroendocrine prostate cancer

Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer-associated deaths among men in the United States. Androgen deprivation therapy (ADT) is the standard of care for advanced prostate cancer. While patients with advanced prostate cancer initially respond to ADT, the disease frequently progresses to a lethal metastatic form, defined as castration-resistant prostate cancer (CRPC). After multiple rounds of anti-androgen therapies, 20-25% of metastatic CRPCs develop a neuroendocrine (NE) phenotype. These tumors are classified as neuroendocrine prostate cancer (NEPC). De novo NEPC is rare and accounts for less than 2% of all prostate cancers at diagnosis. NEPC is commonly characterized by the expression of NE markers and the absence of androgen receptor (AR) expression. NEPC is usually associated with tumor aggressiveness, hormone therapy resistance, and poor clinical outcome. Here, we review the molecular mechanisms underlying the emergence of NEPC and provide insights into the future perspectives on potential therapeutic strategies for NEPC.

Acoustic Fabrication of Living Cardiomyocyte-based Hybrid Biorobots

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.

Protein signatures to distinguish aggressive from indolent prostate cancer

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 (3-5), 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 nonrecurrent cancer were chosen for validation by immunohistochemical analysis on tissue microarrays containing samples from a larger cohort of patients with recurrent and nonrecurrent prostate cancer.

RESULTS

In all, 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 nonrecurrent cancers. Analysis of all differentially expressed proteins in recurrent and nonrecurrent 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.

SU086, an inhibitor of HSP90, impairs glycolysis and represents a treatment strategy for advanced prostate cancer

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 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 displays increased impairment of prostate cancer cell and tumor growth in vitro and in vivo. Cellular thermal shift assay reveals that SU086 binds to heat shock protein 90 (HSP90) and leads to a decrease in HSP90 levels. Proteomic profiling demonstrates that SU086 binds to and decreases HSP90. Metabolomic profiling reveals that SU086 leads to perturbation of glycolysis. Our study identifies SU086 as a treatment for advanced prostate cancer as a single agent or when combined with second-generation anti-androgens.

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SU086 inhibits prostate cancer growth in preclinical models of prostate cancer

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SU086 targets heat shock protein 90

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SU086 alters prostate cancer glycolysis and decreases intratumoral metabolism

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SU086 in combination with anti-androgens halts prostate cancer growth

Metastasis Model to Test the Role of Notch Signaling in Prostate Cancer

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.

Engineering Polysaccharide-Based Hydrogel Photonic Constructs: From Multiscale Detection to the Biofabrication of Living Optical Fibers

Solid-state optics has been the pillar of modern digital age. Integrating soft hydrogel materials with micro/nanooptics could expand the horizons of photonics for bioengineering. Here, wet-spun multilayer hydrogel fibers are engineered through ionic-crosslinked natural polysaccharides that serve as multifunctional platforms. The resulting flexible hydrogel structure and reversible crosslinking provide tunable design properties such as adjustable refractive index and fusion splicing. Modulation of the optical readout via physical stimuli, including shape, compression, and multiple optical inputs/outputs is demonstrated. The unique permeability of the hydrogels is also combined with plasmonic nanoparticles for molecular detection of SARS-CoV-2 in fiber-coupled biomedical swabs. A tricoaxial 3D printing nozzle is then employed for the continuous fabrication of living optical fibers. Light interaction with living cells enables the quantification and digitalization of complex biological phenomena such as 3D cancer progression and drug susceptibility. These fibers pave the way for advances in biomaterial-based photonics and biosensing platforms.

Abstract P157: Targeting Trop2 for treatment of prostate and breast cancer

Background: Prostate cancer and breast cancer are the most commonly diagnosed non-skin cancers and the second leading cause of cancer related mortalities in men and women respectively in the United States. Fifteen percent of breast cancer is TNBC characterized with lack of receptors for estrogen, progesterone, and HER-2/neu making it resistant to hormone therapies and therapies targeting estrogen, progesterone, and HER-2/neu signaling. The first line of treatment for men with advanced prostate cancer is androgen depravation therapy. While initial responses are observed, unfortunately, the disease frequently recurs as a lethal metastatic form referred to as castration-resistant prostate cancer (CRPC). We recently identified that the cell surface receptor, Trop2, is a new regulator of TNBC and CRPC. We demonstrated that Trop2 is highly expressed in CRPC and TNBC. In this study, we set out to test the therapeutic potential of new fully humanized human anti-Trop2 antibody fragments in CRPC and NEPC. Methods: We have generated new human anti-Trop2 antibody fragments. Lentiviral infection was used to generate prostate and breast cancer cell lines with over-expression of Trop2 and knock-down of Trop2. In vivo functional assays were performed including subcutaneous xenograft growth and metastasis. Results: High protein levels of Trop2 are observed in metastatic CRPC and TNBC. Furthermore, loss of Trop2 significantly delays growth, migration and invasion of prostate and breast cancer cells in vitro and delays tumor growth and metastasis of prostate and breast cancer in vivo. Overexpression of Trop2 enhances tumor growth and metastasis of prostate cancer cells and drives CRPC. We generated new fully humanized human anti-Trop2 antibody fragments that have therapeutic efficacy in preclinical models of prostate and breast cancers. Conclusions: In a previous study, we identified cell surface receptor, Trop2, as a novel driver of metastatic CRPC. Herein, our new findings reveal that Trop2 represents a promising therapeutic target for prostate, breast, and potentially other epithelial cancers. We identified lead antibody candidates that bind to human Trop2 protein with high affinity and stability. Furthermore, our lead anti-Trop2 Abs significantly delay the tumors growth in CRPC and TNBC without measurable toxicity and provide new therapeutic strategy for metastatic CRPC and TNBC.

Citation Format: Tanya Stoyanova. Targeting Trop2 for treatment of prostate and breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P157.

Quantifying the invasion and migration ability of cancer cells with a 3D Matrigel drop invasion assay

Metastasis is the main cause of cancer-associated morbidity which will account for ∼ 600,000 deaths in the USA in 2021. Defining new mechanisms that drive cancer metastasis is vital for developing new therapeutic strategies and improving clinical outcomes for cancer patients. Herein, we describe a recently established 3D Matrigel drop invasion assay to measure cancer cell invasion and migration capability in vitro. This assay is a versatile and simple tool to test the ability of cells to invade and migrate, test the functional role of genes of interest in cell invasion and migration, analyze the localization of the target proteins at the cell invasion edge in situ, and screen drug effects on cancer cell invasion and migration.

Ultra-high-frequency radio-frequency acoustic molecular imaging with saline nanodroplets in living subjects

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.

Discovery of CASP8 as a potential biomarker for high-risk prostate cancer through a high-multiplex immunoassay

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.

Ferroptosis Inducers Are a Novel Therapeutic Approach for Advanced Prostate Cancer

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.

Discovery of PTN as a serum-based biomarker of pro-metastatic prostate cancer

Distinguishing clinically significant from indolent prostate cancer (PC) is a major clinical challenge. We utilised targeted protein biomarker discovery approach to identify biomarkers specific for pro-metastatic PC. Serum samples from the cancer-free group; Cambridge Prognostic Group 1 (CPG1, low risk); CPG5 (high risk) and metastatic disease were analysed using Olink Proteomics panels. Tissue validation was performed by immunohistochemistry in a radical prostatectomy cohort (n = 234). We discovered that nine proteins (pleiotrophin (PTN), MK, PVRL4, EPHA2, TFPI-2, hK11, SYND1, ANGPT2, and hK14) were elevated in metastatic PC patients when compared to other groups. PTN levels were increased in serum from men with CPG5 compared to benign and CPG1. High tissue PTN level was an independent predictor of biochemical recurrence and metastatic progression in low- and intermediate-grade disease. These findings suggest that PTN may represent a novel biomarker for the presence of poor prognosis local disease with the potential to metastasise warranting further investigation.

In Vivo Imaging of Methionine Aminopeptidase II for Prostate Cancer Risk Stratification

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.

The role of Trop2 in prostate cancer: an oncogene, biomarker, and therapeutic target

Prostate cancer remains the second leading cause of cancer-associated deaths amongst American men. Trop2, a cell surface glycoprotein, correlates with poor clinical outcome and is highly expressed in metastatic, treatment-resistant prostate cancer. High levels of Trop2 are prognostic for biochemical recurrence. Trop2 regulates tumor growth and metastatic ability of prostate cancer. Moreover, overexpression of Trop2 drives the transdifferentiation to neuroendocrine phenotype in prostate cancer. In addition, Trop2 is overexpressed across epithelial cancers and has emerged as a promising therapeutic target in various solid epithelial cancers. The FDA (Food and Drug Administration) recently approved the use of a Trop2-targeting ADC (antibody-drug conjugate), Sacituzumab Govitecan (IMMU-132), for metastatic, triple-negative breast cancer with at least two prior therapies. Here, we review the role of Trop2 in prostate tumorigenesis and its potential as a promising biomarker and therapeutic target for prostate cancer.

Novel Aza-podophyllotoxin derivative induces oxidative phosphorylation and cell death via AMPK activation in triple-negative breast cancer

BACKGROUND

To circumvent Warburg effect, several clinical trials for different cancers are utilising a combinatorial approach using metabolic reprogramming and chemotherapeutic agents including metformin. The majority of these metabolic interventions work via indirectly activating AMP-activated protein kinase (AMPK) to alter cellular metabolism in favour of oxidative phosphorylation over aerobic glycolysis. The effect of these drugs is dependent on glycaemic and insulin conditions.  Therefore, development of small molecules, which can activate AMPK, irrespective of the energy state, may be a better approach for triple-negative breast cancer (TNBC) treatment.

METHODS

Therapeutic effect of SU212 on TNBC cells was examined using in vitro and in vivo models.

RESULTS

We developed and characterised the efficacy of novel AMPK activator (SU212) that selectively induces oxidative phosphorylation and decreases glycolysis in TNBC cells, while not affecting these pathways in normal cells.   SU212 accomplished this metabolic reprogramming by activating AMPK independent of energy stress and irrespective of the glycaemic/insulin state. This leads to mitotic phase arrest and apoptosis in TNBC cells. In vivo, SU212 inhibits tumour growth, cancer progression and metastasis.

CONCLUSIONS

SU212 directly activates AMPK in TNBC cells, but does not hamper glucose metabolism in normal cells. Our study provides compelling preclinical data for further development of SU212 for the treatment of TNBC.

Gold Nanoclusters for NIR-II Fluorescence Imaging of Bones

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.

Second-Generation Antiandrogens: From Discovery to Standard of Care in Castration Resistant Prostate Cancer

Prostate cancer is the most commonly diagnosed cancer affecting men in the United States. The prostate is a hormone-dependent gland in which androgen hormones testosterone and dihydrotestosterone bind to and activate the androgen receptor, initiating nuclear translocation of androgen receptor and a subsequent signaling cascade. Due to the androgen dependency of the prostate, androgen deprivation therapies have emerged as first line treatment for aggressive prostate cancer. Such therapies are effective until the point at which prostate cancer, through a variety of mechanisms including but not limited to generation of ligand-independent androgen receptor splice variants, or intratumoral androgen production, overcome hormone deprivation. These cancers are androgen ablation resistant, clinically termed castration resistant prostate cancer (CRPC) and remain incurable. First-generation antiandrogens established androgen receptor blockade as a therapeutic strategy, but these therapies do not completely block androgen receptor activity. Efficacy and potency have been improved by the development of second-generation antiandrogen therapies, which remain the standard of care for patients with CRPC. Four second-generation anti-androgens are currently approved by the Food and Drug Administration (FDA); abiraterone acetate, enzalutamide, and recently approved apalutamide and darolutamide. This review is intended to provide a thorough overview of FDA approved second-generation antiandrogen discovery, treatment application, strategies for combination therapy to overcome resistance, and an insight for the potential future approaches for therapeutic inhibition of androgen receptor.

Loss of Notch1 Activity Inhibits Prostate Cancer Growth and Metastasis and Sensitizes Prostate Cancer Cells to Antiandrogen Therapies

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.

Quantitative Proteomic Profiling Reveals Key Pathways in the Anticancer Action of Methoxychalcone Derivatives in Triple Negative Breast Cancer

Triple negative breast cancer is an aggressive, heterogeneous disease with high recurrence and metastasis rates even with modern chemotherapy regimens and thus is in need of new therapeutics. Here, three novel synthetic analogues of chalcones, plant-based molecules that have demonstrated potency against a wide variety of cancers, were investigated as potential therapeutics for triple negative breast cancer. These compounds exhibit IC₅₀ values of ∼5 μM in triple negative breast cancer cell lines and are more potent against triple negative breast cancer cell lines than against nontumor breast cell lines according to viability experiments. Tandem mass tag-based quantitative proteomics followed by gene set enrichment analysis and validation experiments using flow cytometry, apoptosis, and Western blot assays revealed three different anticancer mechanisms for these compounds. First, the chalcone analogues induce the unfolded protein response followed by apoptosis. Second, increases in the abundances of MHC-I pathway proteins occurs, which would likely result in immune stimulation in an organism. And third, treatment with the chalcone analogues causes disruption of the cell cycle by interfering with microtubule structure and by inducing G1 phase arrest. These data demonstrate the potential of these novel chalcone derivatives as treatments for triple negative breast cancer, though further work evaluating their efficacy in vivo is needed.

Abstract B068: Methionine aminopeptidase II (MetAP2) activated in situ self-assembly of small-molecule probes for imaging prostate cancer

Prostate cancer is the most common noncutaneous malignancy among men in the United States and a leading cause of cancer death worldwide. The major clinical challenges in prostate cancer diagnosis include accurate staging, localizing tumors within the prostate, and developing imaging prognostic biomarkers. PET is routinely used in the clinical management of many cancers dues to its high sensitivity (10-15 M), spatial resolution (2-4 mm3), rapid whole-body scan times (&lt;20 min), noninvasiveness, and its ability to provide both anatomic and molecular information when combined with computed tomography (PET/CT). Several PET tracers (e.g., 18F-FDG, 18F-NaF, 11C-choline, 11C-acetate, 18F-fluciclovine, etc.) have been studied for early stage prostate cancer, bone metastases, and recurrent disease; nevertheless, all of these tracers rely on cell uptake and their applications are often limited by the low metabolic activity and a low growth rate of prostate cancer. In this project, we aim to develop a novel enzymatic activity-based PET tracer for in vivo imaging of prostate cancer by targeting methionine aminopeptidase II (MetAP2), a cytosolic metalloprotease that catalyzes the cotranslational removal of the N-terminus initiator methionine residue from nascent proteins. We hypothesize that MetAP2 can serve as a novel diagnostic biomarker of prostate cancer. A MetAP2 activatable molecular imaging probe that self-aggregates in situ can be utilized to image and define this disease. To test our hypothesis, we first measured the expression level of MetAP2 in primary benign human prostate epithelial cells (BS403) and prostate tumor cell lines by Western blot. BS403 cells express significantly lower levels of MetAP2 than PC3 (by 4-fold), DU145 (3-fold), and 22Rv1 (3-fold). The expression of MetAP2 in DU145 tumor xenografts is 12-fold higher and for 22Rv1 14-fold higher, compared to BS403 cells. Immunohistologic analysis of tissues derived from DU145 and 22Rv1 xenografts confirms strong staining of MetAP2. We performed immunohistochemistry on a prostate cancer tissue microarray containing 225 independent patient samples represented in quadruplicate. Positive staining for MetAP2 was found in nearly all of the cancer samples. Encouraged by these data, we designed and synthesized a nonradioactive MetAP2 sensitive nano-aggregation probe called M-SNAP. Incubation of M-SNAP with recombinant MetAP2 enzyme confirmed the formation of the cyclized and aggregated product M-SNAP-cycl by HPLC, TEM (transmission electron microscopy), and DLS (dynamic light scattering). Treatment of PC3 and DU145 cells with or without M-SNAP and the MetAP2 specific inhibitor TNP470 demonstrated MetAP2 dependent intracellular probe aggregation/signal retention using post fluorescent labeling of the cyclized and aggregated products. In future work, we will prepare and study an MetAP2 activatable radioisotope-labeled probe in vitro for sensing and imaging and will evaluate the PET probe in different human prostate xenograft models. MetAP2 sensing probes could provide a highly sensitive and noninvasive PET imaging approach for prostate cancer detection that could be useful in prostate cancer detection, staging, and monitoring of therapeutic response.

Citation Format: Jinghang Xie, Meghan Rice, Yunfeng Cheng, Guosheng Song, Christian Kunder, James D. Brooks, Tanya Stoyanova, Jianghong Rao. Methionine aminopeptidase II (MetAP2) activated in situ self-assembly of small-molecule probes for imaging prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B068.

The Exosome Total Isolation Chip

Circulating tumor-derived extracellular vesicles (EVs) have emerged as a promising source for identifying cancer biomarkers for early cancer detection. However, the clinical utility of EVs has thus far been limited by the fact that most EV isolation methods are tedious, nonstandardized, and require bulky instrumentation such as ultracentrifugation (UC). Here, we report a size-based EV isolation tool called ExoTIC (exosome total isolation chip), which is simple, easy-to-use, modular, and facilitates high-yield and high-purity EV isolation from biofluids. ExoTIC achieves an EV yield ∼4-1000-fold higher than that with UC, and EV-derived protein and microRNA levels are well-correlated between the two methods. Moreover, we demonstrate that ExoTIC is a modular platform that can sort a heterogeneous population of cancer cell line EVs based on size. Further, we utilize ExoTIC to isolate EVs from cancer patient clinical samples, including plasma, urine, and lavage, demonstrating the device's broad applicability to cancers and other diseases. Finally, the ability of ExoTIC to efficiently isolate EVs from small sample volumes opens up avenues for preclinical studies in small animal tumor models and for point-of-care EV-based clinical testing from fingerprick quantities (10-100 μL) of blood.

Low CD38 Identifies Progenitor-like Inflammation-Associated Luminal Cells that Can Initiate Human Prostate Cancer and Predict Poor Outcome

Inflammation is a risk factor for prostate cancer, but the mechanisms by which inflammation increases that risk are poorly understood. Here, we demonstrate that low expression of CD38 identifies a progenitor-like subset of luminal cells in the human prostate. CD38^lo luminal cells are enriched in glands adjacent to inflammatory cells and exhibit epithelial nuclear factor κB (NF-κB) signaling. In response to oncogenic transformation, CD38^lo luminal cells can initiate human prostate cancer in an in vivo tissue-regeneration assay. Finally, the CD38^lo luminal phenotype and gene signature are associated with disease progression and poor outcome in prostate cancer. Our results suggest that prostate inflammation expands the pool of progenitor-like target cells susceptible to tumorigenesis.

Abstract 4917: Therapeutic inhibition of Notch1 in metastatic prostate 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

v-Src Oncogene Induces Trop2 Proteolytic Activation via Cyclin D1

Proteomic analysis of castration-resistant prostate cancer demonstrated the enrichment of Src tyrosine kinase activity in approximately 90% of patients. Src is known to induce cyclin D1, and a cyclin D1-regulated gene expression module predicts poor outcome in human prostate cancer. The tumor-associated calcium signal transducer 2 (TACSTD2/Trop2/M1S1) is enriched in the prostate, promoting prostate stem cell self-renewal upon proteolytic activation via a γ-secretase cleavage complex (PS1, PS2) and TACE (ADAM17), which releases the Trop2 intracellular domain (Trop2 ICD). Herein, v-Src transformation of primary murine prostate epithelial cells increased the proportion of prostate cancer stem cells as characterized by gene expression, epitope characteristics, and prostatosphere formation. Cyclin D1 was induced by v-Src, and Src kinase induction of Trop2 ICD nuclear accumulation required cyclin D1. Cyclin D1 induced abundance of the Trop2 proteolytic cleavage activation components (PS2, TACE) and restrained expression of the inhibitory component of the Trop2 proteolytic complex (Numb). Patients with prostate cancer with increased nuclear Trop2 ICD and cyclin D1, and reduced Numb, had reduced recurrence-free survival probability (HR = 4.35). Cyclin D1, therefore, serves as a transducer of v-Src-mediated induction of Trop2 ICD by enhancing abundance of the Trop2 proteolytic activation complex. Cancer Res; 76(22); 6723-34. ©2016 AACR.

Phosphoproteome Integration Reveals Patient-Specific Networks in Prostate Cancer

We used clinical tissue from lethal metastatic castration-resistant prostate cancer (CRPC) patients obtained at rapid autopsy to evaluate diverse genomic, transcriptomic, and phosphoproteomic datasets for pathway analysis. Using Tied Diffusion through Interacting Events (TieDIE), we integrated differentially expressed master transcriptional regulators, functionally mutated genes, and differentially activated kinases in CRPC tissues to synthesize a robust signaling network consisting of druggable kinase pathways. Using MSigDB hallmark gene sets, six major signaling pathways with phosphorylation of several key residues were significantly enriched in CRPC tumors after incorporation of phosphoproteomic data. Individual autopsy profiles developed using these hallmarks revealed clinically relevant pathway information potentially suitable for patient stratification and targeted therapies in late stage prostate cancer. Here, we describe phosphorylation-based cancer hallmarks using integrated personalized signatures (pCHIPS) that shed light on the diversity of activated signaling pathways in metastatic CRPC while providing an integrative, pathway-based reference for drug prioritization in individual patients.

Abstract 3882: Patient-specific druggable networks in lethal prostate cancer through proteome-guided multi-omic integration

Metastatic castration resistant prostate cancer (CRPC) remains incurable due to the lack of effective therapies. The need to identify new actionable targets in this disease is crucial as we begin to examine the resistance mechanisms related to androgen withdrawal. Pathway activation of signaling proteins, such as kinases, are hypothesized to drive the progression of lethal CRPC. We set out to define the global picture of signaling pathways in lethal prostate cancer through dataset integration. We used clinical tissue from lethal metastatic CRPC patients obtained at rapid autopsy to evaluate and integrate previously published genomic and transcriptomic datasets combined with a new complete and extensive dataset of the phosphoproteome in metastatic CRPC for pathway analysis. This included extending our analysis of the phosphoproteome to phosphoserine and phosphothreonine peptides with our published phosphotyrosine peptide data. Using Tied Diffusion through Interacting Events (TieDIE), we integrated differentially expressed master transcriptional regulators, functionally mutated genes, and differentially activated kinases in CRPC tissues relative to treatment naïve prostate cancer to synthesize a robust signaling network consisting of druggable kinase pathways for therapy. Using MSigDB hallmark gene sets, six major signaling pathways with phosphorylation of several key residues were significantly enriched in CRPC tumors after incorporation of phosphoproteomic data. Further, we were able to gather mRNA and phosphoproteome data from six individual patients where the integration of tissue samples from a single autopsy program allowed us to make inferences on the connections between the mRNA and phosphoproteome datasets. Individual patient profiles developed using these hallmarks revealed clinically relevant pathway information suitable for patient stratification and targeted therapies in lethal prostate cancer. Here we describe these pathways: personalized cancer hallmarks using an integrative phospho-signature (pCHIPs) that sheds light on the diversity of activated signaling pathways in metastatic CRPC while providing an integrative, pathway-based reference for drug prioritization in individual patients.

Citation Format: Justin M. Drake, Evan O. Paull, Nicholas A. Graham, John K. Lee, Bryan A. Smith, Tanya Stoyanova, Claire M. Faltermeier, Daniel E. Carlin, Ajay Vashisht, Jiaoti Huang, James A. Wohlschlegel, Thomas G. Graeber, Owen N. Witte, Joshua M. Stuart. Patient-specific druggable networks in lethal prostate cancer through proteome-guided multi-omic integration. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3882.

N-Myc Drives Neuroendocrine Prostate Cancer Initiated from Human Prostate Epithelial Cells

MYCN amplification and overexpression are common in neuroendocrine prostate cancer (NEPC). However, the impact of aberrant N-Myc expression in prostate tumorigenesis and the cellular origin of NEPC have not been established. We define N-Myc and activated AKT1 as oncogenic components sufficient to transform human prostate epithelial cells to prostate adenocarcinoma and NEPC with phenotypic and molecular features of aggressive, late-stage human disease. We directly show that prostate adenocarcinoma and NEPC can arise from a common epithelial clone. Further, N-Myc is required for tumor maintenance, and destabilization of N-Myc through Aurora A kinase inhibition reduces tumor burden. Our findings establish N-Myc as a driver of NEPC and a target for therapeutic intervention.

Multidisciplinary intervention of early, lethal metastatic prostate cancer: Report from the 2015 Coffey-Holden Prostate Cancer Academy Meeting

BACKGROUND

The 2015 Coffey-Holden Prostate Cancer Academy Meeting, themed: "Multidisciplinary Intervention of Early, Lethal Metastatic Prostate Cancer," was held in La Jolla, California from June 25 to 28, 2015.

METHODS

The Prostate Cancer Foundation (PCF) sponsors an annual, invitation-only, action-tank-structured meeting on a critical topic concerning lethal prostate cancer. The 2015 meeting was attended by 71 basic, translational, and clinical investigators who discussed the current state of the field, major unmet needs, and ideas for addressing earlier diagnosis and treatment of men with lethal prostate cancer for the purpose of extending lives and making progress toward a cure.

RESULTS

The questions addressed at the meeting included: cellular and molecular mechanisms of tumorigenesis, evaluating, and targeting the microenvironment in the primary tumor, advancing biomarkers for clinical integration, new molecular imaging technologies, clinical trials, and clinical trial design in localized high-risk and oligometastatic settings, targeting the primary tumor in advanced disease, and instituting multi-modal care of high risk and oligometastatic patients.

DISCUSSION

This article highlights the current status, greatest unmet needs, and anticipated field changes that were discussed at the meeting toward the goal of optimizing earlier interventions to potentiate cures in high-risk and oligometastatic prostate cancer patients.

Abstract 4985: Notch1 as a key mediator in promoting advanced castration-resistant prostate cancer

The first line of treatment for men with advanced prostate cancers is androgen deprivation therapy. However, the disease commonly relapses in its lethal metastatic form referred to as castration-resistant prostate cancer (CRPC). CRPC is the primary cause of prostate cancer specific mortality in men. Current therapies including chemotherapeutic agents improve median overall survival by only few months. The mechanisms that distinguish clinically localized indolent tumors from lethal CRPC are unclear. Here we demonstrate that ectopic expression of Notch1 promotes progression to poorly differentiated carcinoma when combined with pathways that are altered in advanced disease but are insufficient to drive aggressive prostate cancer alone. Notch1 driven tumors are resistant to androgen deprivation. Transcriptional profiling reveals that these tumors display features of epithelial to mesenchymal transition, a morphological change associated with tumor aggressiveness and metastasis. Our study provides the first functional evidence that Notch1 signaling axis is a key mediator in promoting advanced prostate cancer and may represent a new therapeutic target for the advanced disease.

Note: This abstract was not presented at the meeting.

Citation Format: Tanya Stoyanova, Claire Faltermeier, Bryan Smith, Andrew Goldstein, Xi Zhang, Justin Drake, John Lee, Sandra Orellana, Steven Blum, Donghui Cheng, Kenneth Pienta, Jiaoti Huang, Owen Witte. Notch1 as a key mediator in promoting advanced castration-resistant prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4985. doi:10.1158/1538-7445.AM2015-4985

Distinct phases of human prostate cancer initiation and progression can be driven by different cell-types

The cells that initiate and propagate cancer are important therapeutic targets. However, the progression from cells of origin to tumor-propagating cells is poorly defined for most human cancers. Mouse models indicate that both basal and luminal cells can initiate prostate cancer, while studies with human prostate tissue have demonstrated a role for basal cells in transformation. Our recent study provides evidence that a common cell of origin can produce alternative variants of human epithelial cancer. Our findings also reveal that the cell of origin that initiates cancer is not continuously required to maintain and propagate the disease. Importantly, the cells responsible for initiating human prostate cancer can have a distinct cellular phenotype from the cells needed to maintain it.

Regulated proteolysis of Trop2 drives epithelial hyperplasia and stem cell self-renewal via β-catenin signaling

The cell surface protein Trop2 is expressed on immature stem/progenitor-like cells and is overexpressed in many epithelial cancers. However the biological function of Trop2 in tissue maintenance and tumorigenesis remains unclear. In this study, we demonstrate that Trop2 is a regulator of self-renewal, proliferation, and transformation. Trop2 controls these processes through a mechanism of regulated intramembrane proteolysis that leads to cleavage of Trop2, creating two products: the extracellular domain and the intracellular domain. The intracellular domain of Trop2 is released from the membrane and accumulates in the nucleus. Heightened expression of the Trop2 intracellular domain promotes stem/progenitor self-renewal through signaling via β-catenin and is sufficient to initiate precursor lesions to prostate cancer in vivo. Importantly, we demonstrate that loss of β-catenin or Trop2 loss-of-function cleavage mutants abrogates Trop2-driven self-renewal and hyperplasia in the prostate. These findings suggest that heightened expression of Trop2 is selected for in epithelial cancers to enhance the stem-like properties of self-renewal and proliferation. Defining the mechanism of Trop2 function in self-renewal and transformation is essential to identify new therapeutic strategies to block Trop2 activation in cancer.

Collaboration of Kras and androgen receptor signaling stimulates EZH2 expression and tumor-propagating cells in prostate cancer

Elevation of the chromatin repression factor enhancer of zeste homolog (EZH2) is associated with progression and poor prognosis in several human cancers including prostate cancer. However, the mechanisms driving EZH2 expression are not fully understood. In this study, we investigated the functional synergy in prostate cancers in mice resulting from activation of the androgen receptor, Kras, and Akt, which drives three of the most frequently activated oncogenic signaling pathways in prostate cancer. Although, any two of these three events were sufficient to promote the formation and progression of prostate cancer, only the synergy of androgen receptor and Kras signaling could elevate EZH2 expression and expand prostate cancer progenitor cells in vivo. Our findings have revealed a genetic mechanism resulting in enhanced EZH2 expression during the progression of aggressive prostate cancer, with important implications for understanding how to target advanced disease where cancer progenitor cells may be critical.

Abstract C70: Trop2 regulates prostate tumorigenesis and stem cell self-renewal

Cancer cells share multiple characteristics with adult tissue stem cells such as self-renewal, proliferative capacity and differentiation. Several groups have identified Trop2, a type I trans-membrane glycoprotein, as a marker of stem/progenitor cells in adult tissues. Consistent with the relationship between stem cells and tumorigenesis, we have previously identified that Trop2hi cells are efficient targets for transformation in the prostate. Additionally, Trop2 is highly expressed in various cancers including advanced colorectal, pancreatic, prostate, ovarian and pulmonary carcinomas and is associated with unfavorable outcome. However the functional role of Trop2 in stem cell self-renewal, its relation to transformation, and the molecular mechanisms by which Trop2 transmits signals to regulate these processes remain unclear. We hypothesize that heightened Trop2 may promote the stem-like properties of self-renewal and proliferative activity in prostate cancer.

We observe significantly elevated levels of Trop2 in human prostate cancer, lymph node metastases and in mouse models of prostate cancer. Over-expression of Trop2 induces anchorage-independent growth in vitro and murine prostatic intraepithelial neoplasia (mPIN) in vivo. In vitro sphere and in vivo regeneration assays demonstrate that Trop2 regulates stem/progenitor self-renewal in the prostate, suggesting that elevated levels of Trop2 in prostate cancer are selected for by promoting tumor cell self-renewal.

Biochemical analysis reveals that Trop2 is activated by regulated intra-membrane proteolysis (RIP), resulting in shedding of the extracellular domain (ECD) and release of the intracellular domain (ICD) to the nucleus. RIP is required for Trop2 activity and cleavage mutants of Trop2 fail to enhance self-renewal in vitro. We generated expression constructs of Trop2 ICD and ECD to test their role in self-renewal and tumorigenesis. Secreted Trop2 ECD induces Trop2 cleavage and results in increased stem/progenitor cell proliferation. Trop2 ICD alone promotes self-renewal activity and transformation as measured by sphere formation and in vivo regeneration assays, respectively. Trop2 ICD is sufficient to induce mPIN lesions similar to previously reported mouse models of prostate cancer. These findings suggest that the ICD is the functional unit of Trop2. Trop2 ICD is involved in a signaling cascade that is dependent upon β-catenin to promote self-renewal. We find Trop2 ICD, but not the ECD, forms a complex with β-catenin. While β-catenin loss does not affect baseline sphere-forming activity, we find that over-expression of Trop2 requires the presence of β-catenin to enhance progenitor activity in vitro.

Taken together, our study provides evidence that Trop2 is a key regulator of transformation and self-renewal in the prostate and its function depends on its activation by RIP and downstream signaling through β-catenin. Delineating the molecular mechanism of Trop2 action allows development of therapeutic strategies applicable to not only prostate cancer, but other epithelial malignancies that exhibit increased Trop2 expression. Such strategies include small molecules able to block Trop2 proteolysis, thus inhibiting Trop2 function. More specific therapies such as monoclonal antibodies that will interfere with Trop2 processing and consequent activation could also represent promising future anticancer therapies.

Citation Format: Tanya Stoyanova, Andrew Goldstein, Houjian Cai, Justin M. Drake, Jiaoti Huang, Hong Zhang, Owen N. Witte. Trop2 regulates prostate tumorigenesis and stem cell self-renewal [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C70.

Abstract PR5: Therapeutic targeting of oncogene-specific tyrosine kinase networks during prostate cancer progression

Dominant activating mutations or DNA amplification of tyrosine kinases are not readily observed despite the numerous oncogenic alterations implicated in prostate cancer. We demonstrate that castration resistant prostate cancer (CRPC) exhibits increased tyrosine phosphorylation, raising the question of whether enhanced tyrosine kinase activity is observed in this disease in the absence of specific tyrosine kinase mutations. We generated a mouse model of prostate cancer progression using combinations of commonly perturbed non-tyrosine kinase oncogenes and pathways, including myristoylated Akt (Akt), androgen receptor (AR), Erg, and activated Kras (KrasG12V). We recapitulated the different stages of prostate cancer ranging from prostatic intraepithelial neoplasia (PIN) (Akt) to low grade cancer (Akt+Erg) to highly aggressive prostatic adenocarcinoma (Akt+AR or Akt+KrasG12V). We detected a significant upregulation of tyrosine phosphorylation at the advanced adenocarcinoma stage. Phosphotyrosine peptide enrichment and quantitative mass spectrometry identified oncogene-specific tyrosine kinase signatures, including activation of Egfr Y1172 (Akt+Erg), EphA2 Y595 (Akt+KrasG12V), and Jak2 Y1007/08 (Akt+AR). Kinase:substrate relationship analysis of the phosphopeptides also revealed Abl Y245 and Src Y416 tyrosine kinase activation in Akt+AR tumors; known targets of the tyrosine kinase inhibitor Dasatinib. We are currently evaluating the efficacy of tyrosine kinase inhibitors Dasatinib or Erlotinib on non-tyrosine kinase driven tumors Akt+AR or Akt+Erg, respectively. In summary, the observation of elevated phosphotyrosine signaling in advanced prostate cancer and identification of specific tyrosine kinase pathways from genetically-defined tumor models points to new therapeutic approaches using tyrosine kinase inhibitors for advanced prostate cancer.

This abstract is also presented as Poster C35.

Citation Format: Justin M. Drake, Jiaoti Huang, Thomas G. Graeber, Owen N. Witte, Nicholas A. Graham, Tanya Stoyanova, Amir Sedghi, Andrew S. Goldstein, Houjian Cai, Daniel A. Smith, Hong Zhang, Evangelia Komisopoulou. Therapeutic targeting of oncogene-specific tyrosine kinase networks during prostate cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr PR5.