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This is a revised supplementary material file with unmarked changes.

Purpose: Most currently available chemotherapeutic agents target rampant cell division in cancer cells, thereby affecting rapidly dividing normal cells resulting in toxic side-effects. This nonspecificity necessitates identification of novel cellular pathways that are reprogrammed selectively in cancer cells and can be exploited to develop pharmacologically superior and less toxic therapeutics. Despite growing awareness on dysregulation of lipid metabolism in cancer cells, targeting lipid biosynthesis is still largely uncharted territory. Herein, we report development of a novel nontoxic orally deliverable anticancer formulation of monoethanolamine (Etn) for prostate cancer by targeting the Kennedy pathway of phosphatidylethanolamine (PE) lipid biosynthesis.Experimental Design: We first evaluated gastrointestinal tract stability, drug–drug interaction liability, pharmacokinetic, and toxicokinetic properties of Etn to evaluate its suitability as a nontoxic orally deliverable agent. We next performed in vitro and in vivo experiments to investigate efficacy and mechanism of action.Results: Our data demonstrate that Etn exhibits excellent bioavailability, gastrointestinal tract stability, and no drug–drug interaction liability. Remarkably, orally fed Etn inhibited tumor growth in four weeks by approximately 67% in mice bearing human prostate cancer PC-3 xenografts without any apparent toxicity. Mechanistically, Etn exploits selective overexpression of choline kinase in cancer cells, resulting in accumulation of phosphoethanolamine (PhosE), accompanied by downregulation of HIF-1α that induces metabolic stress culminating into cell death.Conclusions: Our study provides first evidence for the superior anticancer activity of Etn, a simple lipid precursor formulation, whose nontoxicity conforms to FDA-approved standards, compelling its clinical development for prostate cancer management. Clin Cancer Res; 23(14); 3781–93. ©2017 AACR.

This file contains supplementary figures.

Aberrant expression of P68 RNA helicase (p68), a prototypical member of the DEAD box family of RNA helicases, contributes to tumor development and progression. P68 tyrosine phosphorylation induced by PDGF signaling facilitates cancer metastasis by promoting EMT. In this report, we show that p68 promotes breast cancer cell EMT and cell migration by upregulation of PDGF receptor β (PDGFR-β). Knockdown of p68 in MDA-MB-231 and BT549 cells significantly decreases PDGFR-β both in mRNA and protein levels. P68 promotes EMT and cell migration in response to PDGF-BB stimulation via upregulation of PDGFR-β, suggesting that p68 enhances PDGF signaling by a positive feedback loop in cancer cells. Furthermore, our study reveals that p68 mediates the effects of PDGFR-β in regulation of androgen receptor (AR) in breast cancer cells. We demonstrate that p68 and PDGFR-β co-regulate AR expression and promote androgen-mediated proliferation in breast cancer cells. Our studies uncover an important pathway of p68-PDGFR-β axis in promoting breast cancer progression.

Background & Aims Pancreatic ductal adenocarcinoma (PDAC) is resistant to most therapeutics owing to dense fibrotic stroma orchestrated by cancer-associated pancreatic stellate cells (CAPaSC). CAPaSC also support cancer cell growth, metastasis, and resistance to apoptosis. Currently, there is no effective therapy for PDAC that specifically targets CAPaSC. We previously reported a rationally designed protein, ProAgio, that targets integrin αvβ3 at a novel site and induces apoptosis in integrin αvβ3-expressing cells. Because both CAPaSC and angiogenic endothelial cells express high levels of integrin αvβ3, we aimed to analyze the effects of ProAgio in PDAC tumor. Methods Expression of integrin αvβ3 was examined in both patient tissue and cultured cells. The effects of ProAgio on CAPaSC were analyzed using an apoptosis assay kit. The effects of ProAgio in PDAC tumor were studied in 3 murine tumor models: subcutaneous xenograft, genetic engineered (KrasG12D; p53R172H; Pdx1-Cre, GEM-KPC) mice, and an orthotopic KrasG12D; p53R172H; Pdx1-Cre (KPC) model. Results ProAgio induces apoptosis in CAPaSC. ProAgio treatment significantly prolonged survival of a genetically engineered mouse–KPC and orthotopic KPC mice alone or in combination with gemcitabine (Gem). ProAgio specifically induced apoptosis in CAPaSC, resorbed collagen, and opened collapsed tumor vessels without an increase in angiogenesis in PDAC tumor, enabling drug delivery into the tumor. ProAgio decreased intratumoral insulin-like growth factor 1 levels as a result of depletion of CAPaSC and consequently decreased cytidine deaminase, a Gem metabolism enzyme in cancer cells, and thereby reduced resistance to Gem-induced apoptosis. Conclusions Our study suggests that ProAgio is an effective PDAC treatment agent because it specifically depletes CAPaSC and eliminates tumor angiogenesis, thereby enhancing drug delivery and Gem efficacy in PDAC tumors., Graphical abstract

Chronic Liver Diseases (CLD) are characterized by abnormal accumulation of collagen fibrils, neo-angiogenesis, and sinusoidal remodeling. Collagen deposition along with intrahepatic angiogenesis and sinusoidal remodeling alters sinusoid structure resulting in portal hypertension, liver failure, and other complications. Efforts were made to develop treatments for CLDs. However, the success of such treatments is limited and unpredictable. We report a strategy for CLD treatment by induction of integrin αvβ3 mediated cell apoptosis using a rationally designed protein (ProAgio). ProAgio is designed to target integrin αvβ3 at a novel site. Integrin αvβ3 is highly expressed in activated Hepatic Stellate Cells (HSC), angiogenic endothelium, and capillarized Liver Sinusoidal Endothelial Cells (LSEC). ProAgio induces apoptosis of these disease causative cells. Tests with liver fibrosis mouse models demonstrate that ProAgio reverses liver fibrosis and relieves blood flow resistance by depleting activated HSC and capillarized LSEC. Our studies demonstrate an effective approach for CLD treatment., As activated hepatic stellate cells and liver sinusoidal endothelial cells express high levels of integrin α v β3, Turaga et al. present a strategy for treatment of chronic liver disease using their rationally designed protein (ProAgio) which targets integrin α v β3. They find that ProAgio –mediated apoptosis of these disease-associated cells reverses liver fibrosis and ameliorates intrahepatic vascular resistance in a mouse model

Stress and injury to the retinal pigment epithelium (RPE) often lead to dedifferentiation and epithelial-to-mesenchymal transition (EMT). These processes have been implicated in several retinal diseases, including proliferative vitreoretinopathy, diabetic retinopathy, and age-related macular degeneration. Despite the importance of RPE-EMT and the large body of data characterizing malignancy-related EMT, comprehensive proteomic studies to define the protein changes and pathways underlying RPE-EMT have not been reported. This study sought to investigate the temporal protein expression changes that occur in a human-induced pluripotent stem cell–based RPE-EMT model. We utilized multiplexed isobaric tandem mass tag labeling followed by high-resolution tandem MS for precise and in-depth quantification of the RPE-EMT proteome. We have identified and quantified 7937 protein groups in our tandem mass tag–based MS analysis. We observed a total of 532 proteins that are differentially regulated during RPE-EMT. Furthermore, we integrated our proteomic data with prior transcriptomic (RNA-Seq) data to provide additional insights into RPE-EMT mechanisms. To validate these results, we have performed a label-free single-shot data-independent acquisition MS study. Our integrated analysis indicates both the commonality and uniqueness of RPE-EMT compared with malignancy-associated EMT. Our comparative analysis also revealed that multiple age-related macular degeneration–associated risk factors are differentially regulated during RPE-EMT. Together, our integrated dataset provides a comprehensive RPE-EMT atlas and resource for understanding the molecular signaling events and associated biological pathways that underlie RPE-EMT onset. This resource has already facilitated the identification of chemical modulators that could inhibit RPE-EMT, and it will hopefully aid in ongoing efforts to develop EMT inhibition as an approach for the treatment of retinal disease., Graphical Abstract, Highlights • Proteomics data were integrated with prior transcriptomic (RNA-Seq) data on RPE-EMT. • Dysregulated RPE-EMT proteome shares commonality with malignancy-associated EMT. • Altered RPE-EMT proteome signatures correlated with known AMD-associated risk factors. • Protein kinases and phosphatases crosstalk modulate RPE-EMT., In Brief EMT can play a role in retinal diseases. Here, we present a comprehensive proteomic analysis aimed at defining the temporal protein expression changes associated with EMT of stem cell–derived retinal pigment epithelial cells. Tandem mass tag and direct data-independent acquisition MS approaches were performed after inducing RPE-EMT by enzymatic dissociation. We present integration of our proteomic data with prior transcriptomic (RNA-Seq) data to provide additional insights into the RPE-EMT progression.

Early diagnosis and noninvasive detection of liver fibrosis and its heterogeneity remain as major unmet medical needs for stopping further disease progression toward severe clinical consequences. Here we report a collagen type I targeting protein-based contrast agent (ProCA32.collagen1) with strong collagen I affinity. ProCA32.collagen1 possesses high relaxivities per particle (r1 and r2) at both 1.4 and 7.0 T, which enables the robust detection of early-stage (Ishak stage 3 of 6) liver fibrosis and nonalcoholic steatohepatitis (Ishak stage 1 of 6 or 1 A Mild) in animal models via dual contrast modes. ProCA32.collagen1 also demonstrates vasculature changes associated with intrahepatic angiogenesis and portal hypertension during late-stage fibrosis, and heterogeneity via serial molecular imaging. ProCA32.collagen1 mitigates metal toxicity due to lower dosage and strong resistance to transmetallation and unprecedented metal selectivity for Gd3+ over physiological metal ions with strong translational potential in facilitating effective treatment to halt further chronic liver disease progression. Non-invasive early diagnosis of liver fibrosis is important to prevent disease progression and direct treatment strategies. Here the authors developed a collagen-targeting contrast agent for the detection of early stage fibrosis and non-alcoholic steatohepatitis by magnetic resonance and tested it in animal models.

Despite reports of successful clinical cases, many tumors appear to resist infection by oncolytic viruses (OVs). To circumvent this problem, an armed vesicular stomatitis virus was constructed by inserting a transgene to express Smac/DIABLO during virus infection (VSV-S). Endogenous Smac in HeLa cells was diminished during wtVSV infection, whereas the Smac level was enhanced during VSV-S infection. Apoptosis was readily induced by VSV-S, but not wtVSV, infection. More importantly, the tumor volume was reduced to a larger extent when xenografts of 4T1 cells in BALB/c mice and OV-resistant T-47D cells in nude mice were intratumorally injected with VSV-S. VSV-S represents a novel mechanism to overcome tumor resistance, resulting in more significant tumor regression due to enhanced apoptosis.

Sharma et al. present a treatment strategy by simultaneously depleting breast cancer CAFs and tumor angiogenic vessels using a rationally designed protein that induces integrin αvβ3 target-specific cell apoptosis. This offers a unique opportunity for TNBC treatment, especially for patients with dense tumor stroma., Fibrotic tumor stroma plays an important role in facilitating triple-negative breast cancer (TNBC) progression and chemotherapeutic resistance. We previously reported a rationally designed protein (ProAgio) that targets integrin αvβ3 at a novel site. ProAgio induces apoptosis via the integrin. Cancer-associated fibroblasts (CAFs) and angiogenic endothelial cells (aECs) in TNBC tumor express high levels of integrin αvβ3. ProAgio effectively induces apoptosis in CAFs and aECs. The depletion of CAFs by ProAgio reduces intratumoral collagen and decreases growth factors released from CAFs in the tumor, resulting in decreased cancer cell proliferation and apoptotic resistance. ProAgio also eliminates leaky tumor angiogenic vessels, which consequently reduces tumor hypoxia and improves drug delivery. The depletion of CAFs and reduction in hypoxia by ProAgio decreases lysyl oxidase (LOX) secretion, which may play a role in the reduction of metastasis. ProAgio stand-alone or in combination with a chemotherapeutic agent provides survival benefit in TNBC murine models, highlighting the therapeutic potential of ProAgio as a treatment strategy., Graphical Abstract

Purpose: Most currently available chemotherapeutic agents target rampant cell division in cancer cells, thereby affecting rapidly dividing normal cells resulting in toxic side-effects. This nonspecificity necessitates identification of novel cellular pathways that are reprogrammed selectively in cancer cells and can be exploited to develop pharmacologically superior and less toxic therapeutics. Despite growing awareness on dysregulation of lipid metabolism in cancer cells, targeting lipid biosynthesis is still largely uncharted territory. Herein, we report development of a novel nontoxic orally deliverable anticancer formulation of monoethanolamine (Etn) for prostate cancer by targeting the Kennedy pathway of phosphatidylethanolamine (PE) lipid biosynthesis. Experimental Design: We first evaluated gastrointestinal tract stability, drug–drug interaction liability, pharmacokinetic, and toxicokinetic properties of Etn to evaluate its suitability as a nontoxic orally deliverable agent. We next performed in vitro and in vivo experiments to investigate efficacy and mechanism of action. Results: Our data demonstrate that Etn exhibits excellent bioavailability, gastrointestinal tract stability, and no drug–drug interaction liability. Remarkably, orally fed Etn inhibited tumor growth in four weeks by approximately 67% in mice bearing human prostate cancer PC-3 xenografts without any apparent toxicity. Mechanistically, Etn exploits selective overexpression of choline kinase in cancer cells, resulting in accumulation of phosphoethanolamine (PhosE), accompanied by downregulation of HIF-1α that induces metabolic stress culminating into cell death. Conclusions: Our study provides first evidence for the superior anticancer activity of Etn, a simple lipid precursor formulation, whose nontoxicity conforms to FDA-approved standards, compelling its clinical development for prostate cancer management. Clin Cancer Res; 23(14); 3781–93. ©2017 AACR.

Nuclear KIFC1 (nKIFC1) predicts worse outcomes in breast cancer, but its prognostic value within racially distinct triple-negative breast cancer (TNBC) patients is unknown. Thus, nKIFC1 expression was assessed by immunohistochemistry in 163 African American (AA) and 144 White TNBC tissue microarrays (TMAs) pooled from four hospitals. nKIFC1 correlated significantly with Ki67 in White TNBCs but not in AA TNBCs, suggesting that nKIFC1 is not merely a surrogate for proliferation in AA TNBCs. High nKIFC1 weighted index (WI) was associated with significantly worse overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) (Hazard Ratios [HRs] = 3.5, 3.1, and 3.8, respectively; P = 0.01, 0.009, and 0.007, respectively) in multivariable Cox models in AA TNBCs but not White TNBCs. Furthermore, KIFC1 knockdown more severely impaired migration in AA TNBC cells than White TNBC cells. Collectively, these data suggest that nKIFC1 WI an independent biomarker of poor prognosis in AA TNBC patients, potentially due to the necessity of KIFC1 for migration in AA TNBC cells.

The Liver is the most common organ for metastasis for various cancers, including uveal melanoma, the most common primary intraocular tumor. Uveal melanoma metastasizes to the liver in ~90% of patients, and results in death in almost all cases due to late detection and lack of effective treatment. There is a pressing unmet medical need to develop MRI contrast agents and imaging methodologies with desired sensitivity and specificity to overcome the high heterogeneous background and in vivo properties as well as reduced toxicity. Herein, we report the development of a collagen targeting protein contrast agent (ProCA32.collagen1), since collagen is a diagnostic biomarker and therapeutic target for many types of primary and metastatic cancers and the tumor microenvironment. In addition to a strong affinity to collagen I, ProCA32.collagen1 possesses high relaxivities (r1 and r2 are 68.0 ± 0.25 and 100.0 ± 0.32 mM−1 s−1 at 1.4 T, respectively, and 42.6 ± 1.0 and 217 ± 2.4 mM−1s−1 at 7.0 T per particle). ProCA32.collagen1 also has strong serum stability against degradation, resistance to transmetallation, and 102 and 1013-fold higher metal selectivity for Gd3+ over Ca2+ and Zn2+, respectively, compared to clinical contrast agents. ProCA32.collagen1 does not exhibit any cell toxicity for various cell lines. Sensitive detection of liver lesions in animal models can be achieved using multiple imaging methodologies, taking advantage of the dual relaxation property of ProCA32.collagen1. ProCA32.collagen1 enables sensitive and early stage detection of hepatic micrometastasis as small as 0.144 mm2 and two different tumor growth patterns. Further development of ProCA32.collagen1 has the potential to greatly facilitate non-invasive, early detection and staging of primary and metastatic liver cancers, and devising effective treatments.

Background: Pancreatic ductal adenocarcinoma (PDA) is the most lethal form of cancer owing to its insensitivity to many chemotherapeutic drugs. Gemcitabine remains a cornerstone of PDA treatment despite suboptimal efficacy in clinics. One major mechanism by which PDA becomes resistant to gemcitabine is its conversion to inactive derivative, dFdU by upregulation of the enzyme, cytidine deaminase (Cda) in cancer cells. Activated pancreatic stellate cells (PSC) are the major source of IGF1 in the tumor microenvironment, which may be responsible for an increase in Cda expression in cancer cells. We previously reported a rationally designed protein, ProAgio that targets integrin αVβ3 at a novel site. Here we demonstrate that ProAgio specifically induces apoptosis of integrin αVβ3-expressing activated PSC and therefore circumvents gemcitabine resistance in murine PDA models. Objective: To test whether targeting activated PSC restores chemotherapeutic sensitivity in previously unresponsive PDA tumors in a murine model. Methods: To study the effect of ProAgio and gemcitabine combination in PDA, we used two murine PDA models: a) KP orthotopic mouse model where KPC cells were orthotopically injected into the pancreas and, b) LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model. Mice were treated with 20 doses of ProAgio (10mg/kg; i.p.) and 10 doses of gemcitabine twice weekly (50mg/kg; i.p.). IGF1 and Cda levels were analyzed by ELISA and immunohistochemistry. The intratumoral levels of the gemcitabine prodrug 2′,2′-difluorodeoxcytidine (dFdC) and the inactivated and activated metabolites (2′,2′-difluorodeoxyuridine (dFdU) and gemcitabine triphosphate (dFdCTP) respectively were determined by LCMS. Results: Our data in murine PDA models clearly demonstrate that pharmacological targeting of activated PSC by ProAgio can stabilize PDA, and when combined with gemcitabine significantly increased the survival benefit by 3-fold (p Citation Format: Ravi Chakra Turaga, Malvika Sharma, Falguni Mishra, Zhi-Ren Liu. Pharmacological targeting of activated PSC decreases resistance to gemcitabine and increases survival in murine PDA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 117.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer with a five-year survival rate of just 9% after diagnosis. Despite large efforts in developing treatments, the outcome of therapies for patient survival only improves marginally. Dense fibrotic stroma and ECM orchestrated by cancer-associated pancreatic stellate cells (CAPaSC) is considered to be one of the major contributors of resistance to anti-tumor therapies in this disease. The presence of dense collagen fibrils forms a physical block to drug delivery and the completely collapsed intratumoral blood vessels lead to poor blood perfusion resulting in treatment failure. CAPaSC also engage in symbiotic “cross-talk” with cancer cells through cytokines, growth factors, and chemokines supporting cancer cell growth, survival, and resistance to apoptosis. In turn, cancer cells provide factors that support pancreatic stellate cells (PaSC) proliferation and survival. PaSC upon activation express high levels of integrin αVβ3. We previously reported the development of a protein, ProAgio that targets integrin αVβ3 at a novel site and induces apoptosis of integrin αVβ3 expressing cells. We demonstrate here that ProAgio specifically induces apoptosis of CAPaSC and reduces collagen in the pancreatic tumor, enabling delivery of drug molecules into the tumor. Objective: To test whether targeting CAPaSC reduces the pathological progression of PDAC in murine models. Methods: We examined the effects of ProAgio in vitro and in a xenograft mouse model in vivo wherein Panc-1 cells were co-implanted with immortalized and activated human PaSC. Further, we used two murine PDAC models: a) Genetically engineered mouse (GEM) KPC model, and, b) KP orthotopic mouse model where KPC cells were orthotopically injected into the pancreas. Mice were treated with 20 doses of ProAgio (10mg/kg; i.p.). Tumor histological analysis was performed. Drug diffusion was measured by administering Fluor 595-conjugated goat IgG via tail vein. Results: PaSC promoted the growth of pancreatic cancer cells in vitro. Integrin αVβ3 is highly upregulated in CAPaSC and ProAgio effectively induced apoptosis of CAPaSC. ProAgio treatment markedly inhibited the tumor growth when Panc-1 cells were co-implanted with activated human PaSC. In more clinically relevant models, such as GEM KPC and KP orthotopic mouse models, ProAgio treatment exhibited around 60-70% decrease in α-SMA positive cells and intratumoral collagen levels. In addition, ProAgio treatment decompressed the intratumoral vessels without an increase in angiogenesis and significantly increased the delivery of drug into the tumor. In conclusion, our findings for the first time demonstrate that ProAgio may potentially be a unique agent that is capable of specifically depleting CAPaSC in PDAC to facilitate treatment. Citation Format: Malvika Sharma, Ravi Chakra Turaga, Falguni Mishra, Yi Yuan, Zhi-Ren Liu. Modulation of cancer-associated fibrotic stroma reduces pathological progression of PDAC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 110.

Background: TNBC metastasis is responsible for a majority of the mortalities associated with breast cancer across the globe. Cancers metastasize to various distant organs such as lungs, liver, and bones, which accounts for a low 5-year survival rate. Lung offers the most favorable environment and is, therefore, the most common metastatic site in the majority of patients. Currently, there are no effective targeted therapies for breast cancer metastasis and hence there is a dire clinical need to establish treatment for this disease. It is noteworthy that tumor growth and metastasis is supported by the surrounding stroma, also known as the tumor microenvironment (TME) that promotes the proliferation of cancer cells by secreting various growth factors and cytokines. Despite growing awareness of the role of the TME in tumor progression, targeting cells that comprise the majority of the TME is still uncharted territory. TME is composed of a variety of cell types, with cancer-associated fibroblasts (CAFs) - cells that express high levels of integrin αVβ3 - being the predominant cell type. Here we report the development of a novel, rationally designed protein, ProAgio, which induces apoptosis of integrin αVβ3 expressing cells via a novel mechanism. Objectives: To test the efficacy of ProAgio in targeting the TME in TNBC. To elucidate the mechanism through which ProAgio exerts an anti-metastatic effect. Methods: We implanted 4T1 cells orthotopically in Balb/c mice and treated them with 10 doses of ProAgio (10mg/kg; i.p.) when the tumor volume reached around 250mm3. Another in vivo experiment was performed with the 4T1 model to see the effect of ProAgio in combination with a chemotherapeutic agent, doxorubicin (DOX) (3mg weekly i.p.). The tissues isolated were stained for collagen and α-SMA (CAF marker). Breast and lung fibroblasts were differentiated with TGF-β (5ng/mL) for two weeks and annexin V staining was used to measure their apoptosis. Results: Our data demonstrate that ProAgio inhibits breast tumor growth and metastasis to lungs by decreasing collagen and CAFs in 4T1 tumor-bearing mice. Histological analyses of the tissues exhibit decreased collagen and α-SMA in both breast tumor and lungs upon ProAgio treatment. Mechanistically, ProAgio induces integrin αVβ3-mediated apoptosis in breast and lung CAFs. In addition, ProAgio shows no effect on 4T1 breast cancer cells as they lack αVβ3 expression. Our study demonstrates that a combination of ProAgio and DOX exhibits improved anti-tumor efficacy and enhances survival in the 4T1 murine model. In conclusion, our study reports the first evidence of inducing apoptosis in CAFs and shows antitumor synergy for combined therapy, supporting the significant therapeutic potential of ProAgio as a stand-alone therapy and more effectively when combined with chemotherapy. Citation Format: Malvika Sharma, Ravi Chakra Turaga, Yi Yuan, Falguni Mishra, Zhi-Ren Liu. Therapeutic targeting of cancer-associated fibroblasts by a novel protein, ProAgio, effectively decreases TNBC growth and metastasis to the lungs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2124.

Human breast tumors harbor supernumerary centrosomes in almost 80% of tumor cells. Although amplified centrosomes compromise cell viability via multipolar spindles resulting in death-inducing aneuploidy, cancer cells tend to cluster extra centrosomes during mitosis. As a result cancer cells display bipolar spindle phenotypes to maintain a tolerable level of aneuploidy, an edge to their survival. HSET/KifC1, a kinesin-like minus-end directed microtubule motor has recently found fame as a crucial centrosome clustering molecule. Here we show that HSET promotes tumor progression via mechanisms independent of centrosome clustering. We found that HSET is overexpressed in breast carcinomas wherein nuclear HSET accumulation correlated with histological grade and predicted poor progression-free and overall survival. In addition, deregulated HSET protein expression was associated with gene amplification and/or translocation. Our data provide compelling evidence that HSET overexpression is pro-proliferative, promotes clonogenic-survival and enhances cell-cycle kinetics through G2 and M-phases. Importantly, HSET co-immunoprecipitates with survivin, and its overexpression protects survivin from proteasome-mediated degradation, resulting in its increased steady-state levels. We provide the first evidence of centrosome clustering-independent activities of HSET that fuel tumor progression and firmly establish that HSET can serve both as a potential prognostic biomarker and as a valuable cancer-selective therapeutic target.

Classical anti-mitotic drugs have failed to translate their preclinical efficacy into clinical response in human trials. Their clinical failure has challenged the notion that tumor cells divide frequently at rates comparable to those of cancer cells in vitro and in xenograft models. Given the preponderance of interphase cells in clinical tumors, we asked whether targeting amplified centrosomes, which cancer cells carefully preserve in a tightly clustered conformation throughout interphase, presents a superior chemotherapeutic strategy that sabotages interphase-specific cellular activities, such as migration. Herein we have utilized supercentrosomal N1E-115 murine neuroblastoma cells as a test-bed to study interphase centrosome declustering induced by putative declustering agents, such as Reduced-9-bromonoscapine (RedBr-Nos), Griseofulvin and PJ-34. We found tight ‘supercentrosomal’ clusters in the interphase and mitosis of ~80% of patients’ tumor cells with excess centrosomes. RedBr-Nos was the strongest declustering agent with a declustering index of 0.36 and completely dispersed interphase centrosome clusters in N1E-115 cells. Interphase centrosome declustering caused inhibition of neurite formation, impairment of cell polarization and Golgi organization, disrupted cellular protrusions and focal adhesion contacts—factors that are crucial prerequisites for directional migration. Thus our data illustrate an interphase-specific potential anti-migratory role of centrosome-declustering agents in addition to their previously acknowledged ability to induce spindle multipolarity and mitotic catastrophe. Centrosome-declustering agents counter centrosome clustering to inhibit directional cell migration in interphase cells and set up multipolar mitotic catastrophe, suggesting that disbanding the nuclear–centrosome–Golgi axis is a potential anti-metastasis strategy.

Endothelial tubular morphogenesis relies on an exquisite interplay of microtubule dynamics and actin remodeling to propel directed cell migration. Recently, the dynamicity and integrity of microtubules have been implicated in the trafficking and efficient translation of the mRNA for HIF-1α (hypoxia-inducible factor), the master regulator of tumor angiogenesis. Thus, microtubule-disrupting agents that perturb the HIF-1α axis and neovascularization cascade are attractive anticancer drug candidates. Here we show that EM011 (9-bromonoscapine), a microtubule-modulating agent, inhibits a spectrum of angiogenic events by interfering with endothelial cell invasion, migration and proliferation. Employing green-fluorescent transgenic zebrafish, we found that EM011 not only inhibited vasculogenesis but also disrupted preexisting vasculature. Mechanistically, EM011 caused proteasome-dependent, VHL-independent HIF-1α degradation and repressed expression of HIF-1α downstream targets, namely VEGF and survivin. Furthermore, EM011 inhibited membrane ruffling and impeded formation of filopodia, lamellipodia and stress fibers, which are critical for cell migration. These events were associated with a drug-mediated decrease in activation of Rho GTPases- RhoA, Cdc42 and Rac1, and correlated with a loss in the geometric precision of centrosome reorientation in the direction of movement. This is the first report to describe a previously unrecognized, antiangiogenic property of a noscapinoid, EM011, and provides evidence for novel anticancer strategies recruited by microtubule-modulating drugs.