Comparing the BAD Protein Interactomes in 2D and 3D Cell Culture Using Proximity Labeling.

Protein-protein interaction studies using proximity labeling techniques, such as biotin ligase-based BioID, have become integral in understanding cellular processes. Most studies utilize conventional 2D cell culture systems, potentially missing important differences in protein behavior found in 3D tissues. In this study, we investigated the protein-protein interactions of a protein, Bcl-2 Agonist of cell death (BAD), and compared conventional 2D culture conditions to a 3D system, wherein cells were embedded within a 3D extracellular matrix (ECM) mimic. Using BAD fused to the engineered biotin ligase miniTurbo (BirA*), we identified both overlapping and distinct BAD interactomes under 2D and 3D conditions. The known BAD binding proteins 14-3-3 isoforms and Bcl-XL interacted with BAD in both 2D and 3D. Of the 131 BAD-interactors identified, 56% were specific to 2D, 14% were specific to 3D, and 30% were common to both conditions. Interaction network analysis demonstrated differential associations between 2D and 3D interactomes, emphasizing the impact of the culture conditions on protein interactions. The 2D-3D overlap interactome encapsulated the apoptotic program, which is a well-known role of BAD. The 3D unique pathways were enriched in ECM signaling, suggestive of hitherto unknown functions for BAD. Thus, exploring protein-protein interactions in 3D provides novel clues into cell behavior. This exciting approach has the potential to bridge the knowledge gap between tractable 2D cell culture and organoid-like 3D systems.

Cancer invasion and metastasis: Insights from murine pubertal mammary gland morphogenesis.

Cancer invasion and metastasis accounts for the majority of cancer related mortality. A better understanding of the players that drive the aberrant invasion and migration of tumors cells will provide critical targets to inhibit metastasis. Postnatal pubertal mammary gland morphogenesis is characterized by highly proliferative, invasive, and migratory normal epithelial cells. Identifying the molecular regulators of pubertal gland development is a promising strategy since tumorigenesis and metastasis is postulated to be a consequence of aberrant reactivation of developmental stages. In this review, we summarize the pubertal morphogenesis regulators that are involved in cancer metastasis and revisit pubertal mammary gland transcriptome profiling to uncover both known and unknown metastasis genes. Our updated list of pubertal morphogenesis regulators shows that most are implicated in invasion and metastasis. This review highlights molecular linkages between development and metastasis and provides a guide for exploring novel metastatic drivers.

Attenuation of obesity-induced hyperlipidemia reduces tumor growth.

Accumulating evidence suggests that hyperlipidemia is associated with obesity and cancer mortality in humans. We tested the hypotheses that inhibition of microsomal triglyceride transfer protein (MTP) would attenuate obesity-induced hyperlipidemia and reduce tumor growth by treating BCR-ABL B cell tumor-bearing hyperlipidemic obese ob/ob obese mice with a MTP inhibitor. MTP inhibition in tumor-bearing mice reduced concentrations of plasma apoB100 5-fold together with a corresponding decrease in VLDL triacylglycerol (TG) and cholesterol. Inhibition of MTP decreased tumor volume by 50%. MTP inhibitor did not alter tumor cell viability in vitro, suggesting that the in vivo tumor shrinkage effect was related to altered circulating lipids. Tumor volume reduction occurred without change in the protein expression of LDLR, FASN and HMGCR in the tumor, suggesting a lack of compensatory mechanisms in response to decreased hyperlipidemia. Expression of genes encoding GLUT4 and PEPCK was increased 6- and 10-fold, respectively, but no change in the expression of genes encoding regulatory enzymes of glycolysis was observed, suggesting that the tumors were not dependent on or switching to carbohydrates for energy requirement to support their growth. No change of proliferative signaling PI3K/AKT and ERK pathways after MTP inhibition was observed in the tumors. In conclusion, MTP inhibition decreased dyslipidemia and tumor growth in obese, insulin resistant mice. Therefore, decreasing VLDL secretion could be further explored as an adjuvant therapeutic intervention together with standard care to reduce tumor growth in obese patients.

BAD regulates mammary gland morphogenesis by 4E-BP1-mediated control of localized translation in mouse and human models.

Elucidation of non-canonical protein functions can identify novel tissue homeostasis pathways. Herein, we describe a role for the Bcl-2 family member BAD in postnatal mammary gland morphogenesis. In Bad3SA knock-in mice, where BAD cannot undergo phosphorylation at 3 key serine residues, pubertal gland development is delayed due to aberrant tubulogenesis of the ductal epithelium. Proteomic and RPPA analyses identify that BAD regulates focal adhesions and the mRNA translation repressor, 4E-BP1. These results suggest that BAD modulates localized translation that drives focal adhesion maturation and cell motility. Consistent with this, cells within Bad3SA organoids contain unstable protrusions with decreased compartmentalized mRNA translation and focal adhesions, and exhibit reduced cell migration and tubulogenesis. Critically, protrusion stability is rescued by 4E-BP1 depletion. Together our results confirm an unexpected role of BAD in controlling localized translation and cell migration during mammary gland development.

BIK drives an aggressive breast cancer phenotype through sublethal apoptosis and predicts poor prognosis of ER-positive breast cancer.

Apoptosis is fundamental to normal animal development and is the target for many anticancer therapies. Recent studies have explored the consequences of "failed apoptosis" where the apoptotic program is initiated but does not go to completion and does not cause cell death. Nevertheless, this failed apoptosis induces DNA double-strand breaks generating mutations that facilitate tumorigenesis. Whether failed apoptosis is relevant to clinical disease is unknown. BCL-2 interacting killer (BIK) is a stress-induced BH3-only protein that stimulates apoptosis in response to hormone and growth factor deprivation, hypoxia, and genomic stress. It was unclear whether BIK promotes or suppresses tumor survival within the context of breast cancer. We investigated this and show that BIK induces failed apoptosis with limited caspase activation and genomic damage in the absence of extensive cell death. Surviving cells acquire aggressive phenotypes characterized by enrichment of cancer stem-like cells, increased motility and increased clonogenic survival. Furthermore, by examining six independent cohorts of patients (total n = 969), we discovered that high BIK mRNA and protein levels predicted clinical relapse of Estrogen receptor (ER)-positive cancers, which account for almost 70% of all breast cancers diagnosed but had no predictive value for hormone receptor-negative (triple-negative) patients. Thus, this study identifies BIK as a biomarker for tumor recurrence of ER-positive patients and provides a potential mechanism whereby failed apoptosis contributes to cancer aggression.

BAD sensitizes breast cancer cells to docetaxel with increased mitotic arrest and necroptosis.

Breast cancer patients are commonly treated with taxane (e.g. docetaxel) chemotherapy, despite poor outcomes and eventual disease relapse. We previously identified the Bcl-2-associated death promoter (BAD) as a prognostic indicator of good outcome in taxane-treated breast cancer patients. We also demonstrated that BAD expression in human breast carcinoma cells generated larger tumors in mouse xenograft models. These paradoxical results suggest that BAD-expressing tumors are differentially sensitive to taxane treatment. We validated this here and show that docetaxel therapy preferentially reduced growth of BAD-expressing xenograft tumors. We next explored the cellular mechanism whereby BAD sensitizes cells to docetaxel. Taxanes are microtubule inhibiting agents that cause cell cycle arrest in mitosis whereupon the cells either die in mitosis or aberrantly exit (mitotic slippage) and survive as polyploid cells. In response to docetaxel, BAD-expressing cells had lengthened mitotic arrest with a higher proportion of cells undergoing death in mitosis with decreased mitotic slippage. Death in mitosis was non-apoptotic and not dependent on Bcl-XL interaction or caspase activation. Instead, cell death was necroptotic, and dependent on ROS. These results suggest that BAD is prognostic for favourable outcome in response to taxane chemotherapy by enhancing necroptotic cell death and inhibiting the production of potentially chemoresistant polyploid cells.

Latent Cytomegalovirus Infection in Female Mice Increases Breast Cancer Metastasis.

Cytomegalovirus (CMV) infects 40⁻70% of women, but infection has been reported in >95% of breast cancer patients. We investigated the consequences of these observations by infecting mice with mCMV or a negative control medium for 4 days, 11 days or 10 weeks to establish active, intermediate or latent infections, respectively. Syngeneic 4T1 or E0771 breast cancer cells were then injected into a mammary fat pad of BALB/c or C57BL/6 mice, respectively. Infection did not affect tumor growth in these conditions, but latently infected BALB/c mice developed more lung metastases. The latent mCMV infection of MMTV-PyVT mice, which develop spontaneous breast tumors, also did not affect the number or sizes of breast tumors. However, there were more tumors that were multilobed with greater blood content, which had enhanced vasculature and decreased collagen content. Most significantly, mCMV infection also increased the number and size of lung metastases, which showed a higher cell proliferation. Viral DNA was detected in breast tumors and lung nodules although viral mRNA was not. These novel results have important clinical implications since an increased metastasis is prognostic of decreased survival. This work provides evidence that treating or preventing HCMV infections may increase the life expectancy of breast cancer patients by decreasing metastasis.

Non-canonical BAD activity regulates breast cancer cell and tumor growth via 14-3-3 binding and mitochondrial metabolism.

The Bcl-2-associated death promoter BAD is a prognostic indicator for good clinical outcome of breast cancer patients; however, whether BAD affects breast cancer biology is unknown. Here we showed that BAD increased cell growth in breast cancer cells through two distinct mechanisms. Phosphorylation of BAD at S118 increased S99 phosphorylation, 14-3-3 binding and AKT activation to promote growth and survival. Through a second, more prominent pathway, BAD stimulated mitochondrial oxygen consumption in a novel manner that was downstream of substrate entry into the mitochondria. BAD stimulated complex I activity that facilitated enhanced cell growth and sensitized cells to apoptosis in response to complex I blockade. We propose that this dependence on oxidative metabolism generated large but nonaggressive cancers. This model identifies a non-canonical role for BAD and reconciles BAD-mediated tumor growth with favorable outcomes in BAD-high breast cancer patients.

What research is needed to validate new urodynamic methods? ICI-RS2017.

AIMS: In recent years urodynamic innovations, although well researched, have failed to follow a standardized development pathway specifically in terms of clinical trials undertaken to demonstrate efficacy. This was discussed at the International Consultation on Incontinence Research Society (ICI-RS) in Bristol, United Kingdom, 2017 with the aim of defining minimum standards for future urodynamic research. METHODS: The recent recommendations from the IDEAL (innovation, development, exploration, assessment, and long-term study) collaboration regarding surgical research were reviewed. Two examples of recent novel urodynamic technologies, the penile cuff test and air charged urodynamic catheters were used as case studies and the research programmes behind their development were critiqued. RESULTS: The rigorous and standardized model of surgical research proposed by the IDEAL collaboration was endorsed as an appropriate model for future urodynamic research. A methodical approach to research can fulfil a host of objectives including illustration of the clinical need, help with design and refinement of technique and proving efficacy for any new test or device. The penile cuff test is a novel urodynamic measurement technique that has been well researched and is now used in clinical practice. Further research is needed before air charged catheters can be recommended for widespread clinical use and the IDEAL framework provides a template for ongoing development. CONCLUSIONS: In the future, these recommendations should lead to a more standardized and uniform programme of urodynamic research and enable a thorough evaluation of new technologies prior to wider clinical uptake.

Identification and Characterization of Novel Receptor-Interacting Serine/Threonine-Protein Kinase 2 Inhibitors Using Structural Similarity Analysis.

Receptor-interacting protein kinase 2 (RIP2 or RICK, herein referred to as RIPK2) is linked to the pathogen pathway that activates nuclear factor κ-light-chain-enhancer of activated B cells (NFκB) and autophagic activation. Using molecular modeling (docking) and chemoinformatics analyses, we used the RIPK2/ponatinib crystal structure and searched in chemical databases for small molecules exerting binding interactions similar to those exerted by ponatinib. The identified RIPK2 inhibitors potently inhibited the proliferation of cancer cells by > 70% and also inhibited NFκB activity. More importantly, in vivo inhibition of intestinal and lung inflammation rodent models suggests effectiveness to resolve inflammation with low toxicity to the animals. Thus, our identified RIPK2 inhibitor may offer possible therapeutic control of inflammation in diseases such as inflammatory bowel disease, asthma, cystic fibrosis, primary sclerosing cholangitis, and pancreatitis.

Comparing a novel hand held device (Peritron+) to standard urodynamics in measuring intravesical pressure.

AIMS: Peritron+ is a new handheld device, which can be attached to a urethral catheter to measure intravesical pressures (Pves). The goal of this study was to assess if Pves recorded by standard urodynamics (UDs) are comparable to those recorded by the Peritron+. METHODS: Patients with voiding dysfunction and an indication for UD underwent measurement of Pves with nonvideo UD and Peritron+. Pves were recorded at volumes of 50, 100, and 200 mL for the supine and sitting positions. A failure of the Peritron+ was considered to be a discrepancy of Pves values >3 cmH2 O between Peritron+ and UD recordings. Two-way ANOVA was used to assess for statistical significance. P-values < 0.05 were considered significant. RESULTS: Ten female patients, mean age 51 years old, were enrolled in the study. The difference in Pves measurements between Peritron+ and UD were ≤3 cmH2 O at all bladder volumes measured in a supine and sitting positions. There were no adverse events and there were no malfunctions of the Peritron+ device during the study. CONCLUSIONS: Peritron+ handheld device accurately assessed Pves at different intravesical volumes when compared to UD measurements. The Peritron+ is a simple and safe device, which can be used in the office by a clinician and at home by a patient to monitor Pves and help to select patients who may require standard UD re-evaluation. This will be a valuable tool in managing patients with neurogenic and nonneurogenic bladders who are at a risk of upper urinary tract deterioration.

Performance analysis of the T-DOC® air-charged catheters: An alternate technology for urodynamics.

AIMS: Urodynamics (UDS) is widely used for the diagnosis of lower urinary tract dysfunction. Air-Charged catheters (ACC), one of the newer technologies for UDS pressure recording, has been adopted in growing numbers around the world for the past 15 years. Currently, there is a lack of published studies characterizing specific performance of the ACC. Since linearity, hysteresis, pressure drift, and frequency response are important components in characterizing accuracy for catheter-manometer systems; this study aimed to assess these four aspects in ACC. METHODS: A total of 180 T-DOC® ACC were used in three different laboratory settings to assess pressure linearity and hysteresis (15 dual-sensor vesical and urethral and 30 single-sensor abdominal), pressure drift over 2 h (115 single-sensor), and frequency response (20 single-sensor). Data are presented as mean ± standard deviation. RESULTS: ACC showed linearity of 0.99 ± 0.01, 0.99 ± 0.01, and 1.01 ± 0.01; and hysteresis of 0.57 ± 0.3%, 0.76 ± 0.48%, and 1 ± 0.89% for the abdominal, vesical, and urethral sensors, respectively. A pressure drift of 2.2 ± 1.4% at 1 h and 4.4 ± 2.5% at 2 h were observed when compared to baseline pressures. The catheters did not show any amplification factor during the sweep from 1 to 30 Hz, and recorded signals up to 5 Hz attenuating higher frequency signals. CONCLUSIONS: In this study the T-DOC® ACC showed a linear performance with minimal hysteresis associated with acceptable pressure drift, and adequate frequency response to capture clinically relevant pressures. The accurate results observed in this study suggest that these catheters are technically suitable to be used as a measuring instrument for UDS.

Urethral pressure variation: a neglected contributing factor in patients with overactive bladder syndrome?

ABSTRACT Objective To study urethral pressure variations during the whole filling phase among different groups of patients. Material and Methods We investigated 79 consecutive patients from January 2011 to June 2012. All patients were recruited within our routine practice in our continence clinic and were evaluated with urodynamic exam according to the standards of the International Continence Society (ICS) with an additional continuous measurement of the urethral pressure profile (cUPP) that was done in a supine position. Patients with genital prolapse >grade I, as well as patients with impaired cognitive function or neurogenic disorders were excluded. Bacteriuria at the time of investigation was excluded by urine analysis. Urethral pressure changes higher than 15cmH2O were considered as ‘urethral instability’. Results From 79 investigated patients, 29 were clinically diagnosed with OAB syndrome, 19 with stress urinary incontinence (SUI) and 31 with mixed (OAB and SUI) incontinence. The prevalence of ‘urethral instability’ as defined in this study was 54.4% (43/79). The mean Δp in patients with OAB (36.5cmH2O) was significantly higher (p<0.05) than in groups with pure stress (14.9cmH2O) and mixed urinary incontinence (19.3cmH2O). Conclusions Etiology of ‘urethral instability’ is unknown, but high prevalence among patients with overactive bladder syndrome, especially concomitant with detrusor activity can raise a fair question and direct further diagnostic as well as treatment efforts.

Photo-activation of the delocalized lipophilic cation D112 potentiates cancer selective ROS production and apoptosis.

Delocalized lipophilic cations (DLCs) selectively accumulate in cancer cell mitochondria and have long been explored for therapeutic applications. Although targeted effects to cancer cells are demonstrated in vitro, non-specific toxicities in vivo have hampered clinical development. Identifying the molecular mechanisms of action and enhancing selectivity are thus necessary next steps to improve these compounds and evaluate their suitability for further drug development. D112 is one such DLC with promising properties. We previously demonstrated that D112 selectively induced intrinsic apoptosis in transformed versus non-transformed cell lines. Here we show that D112 preferentially entered transformed cells where it interacted with, and damaged mitochondrial DNA, inhibited Complex I respiration and induced reactive oxygen species (ROS). ROS production was critical for Bax activation and subsequent apoptosis. Importantly, photo-activation of D112 potentiated selective ROS production and increased the window of toxicity towards cancer cells over non-transformed cells. Thus photodynamic therapy would be an exciting adjunct to D112 studies and may be generally applicable for other DLCs that are currently under therapeutic investigation.

Novel Colchicine Derivatives and their Anti-cancer Activity.

In this paper we provide an overview of the status of various colchicine derivatives in preclinical development with special focus on their anti-cancer activity. We discuss several groups of compounds that have been designed to differentially bind with specific affinities for tubulin ß isotypes, especially in regard to ßIII, which is commonly over-expressed in cancer. Computational prediction, protein-based and cell-based assays are summarized as well as some animal tests conducted on these compounds. It is concluded that an untapped potential exists for exploiting the colchicine scaffold as a pharmacophore with the possibility of increasing its affinity for tubulin isotypes overexpressed in cancer and decreasing it for normal cells thereby widening the therapeutic window.

The pro-apoptotic paradox: the BH3-only protein Bcl-2 interacting killer (Bik) is prognostic for unfavorable outcomes in breast cancer.

Breast cancer is the leading cause of cancer-associated deaths in women worldwide. Clinical biomarkers give information on disease progression and identify relevant biological pathways. A confounding factor that uncouples markers from disease outcome is the ability of tumor cells to mutate and evade clinical intervention. Therefore, we focussed on apoptotic genes that modulate tumor regression. Using gene and tissue microarray analyses, we identified an association of Bcl-2 interacting killer (Bik) with poor breast cancer prognosis. Bik prognostic ability was independent of Estrogen Receptor/Progesterone Receptor and Her2 status. Additionally, Bik was independent of anti-apoptotic Bcl-2, Bcl-xL, Mcl-1 and Bcl-w suggesting a complex mechanism of tumor promotion identified by Bik high tumors. Bik also stimulates autophagy, which can contribute to enhanced tumor fitness. We found a significant association between the autophagy marker ATG5 and Bik. Combined high expression level of ATG5 and Bik was a stronger predictor of outcome than either alone. Thus, our study identifies Bik as a novel, independent prognostic biomarker for poor outcomes in breast cancer and suggests that Bik-mediated autophagy contributes to disease recurrence.

Characterization of the apoptotic response induced by the cyanine dye D112: a potentially selective anti-cancer compound.

Chemotherapeutic drugs that are used in anti-cancer treatments often cause the death of both cancerous and noncancerous cells. This non-selective toxicity is the root cause of untoward side effects that limits the effectiveness of therapy. In order to improve chemotherapeutic options for cancer patients, there is a need to identify novel compounds with higher discrimination for cancer cells. In the past, methine dyes that increase the sensitivity of photographic emulsions have been investigated for anti-cancer properties. In the 1970's, Kodak Laboratories initiated a screen of approximately 7000 dye structural variants for selective toxicity. Among these, D112 was identified as a promising compound with elevated toxicity against a colon cancer cell line in comparison to a non-transformed cell line. Despite these results changing industry priorities led to a halt in further studies on D112. We decided to revive investigations on D112 and have further characterized D112-induced cellular toxicity. We identified that in response to D112 treatment, the T-cell leukemia cell line Jurkat showed caspase activation, mitochondrial depolarization, and phosphatidylserine externalization, all of which are hallmarks of apoptosis. Chemical inhibition of caspase enzymatic activity and blockade of the mitochondrial pathway through Bcl-2 expression inhibited D112-induced apoptosis. At lower concentrations, D112 induced growth arrest. To gain insight into the molecular mechanism of D112 induced mitochondrial dysfunction, we analyzed the intracellular localization of D112, and found that D112 associated with mitochondria. Interestingly, in the cell lines that we tested, D112 showed increased toxicity toward transformed versus non-transformed cells. Results from this work identify D112 as a potentially interesting molecule warranting further investigation.

Do we need better methods of assessing urethral function: ICI-RS 2013?

AIMS: To assess whether current methods of urethral function assessment are sufficient for clinical requirement. METHODS: A summary of the debate held at the 2013 meeting of the International Consultation on Incontinence Research Society, with subsequent analysis by the authors. RESULTS: All reported methods of assessment were reviewed and a summary of reported efficacy and clinical application for each is given. Every method of assessment has limitations as to its use, and in some cases the methods have yet to be proved reliable. CONCLUSIONS: A gap exists between clinical requirements and the capacity of current urethral function assessments to assist diagnosis. Recommendations are therefore made for future research topics.

Granzyme B degradation by autophagy decreases tumor cell susceptibility to natural killer-mediated lysis under hypoxia.

Recent studies demonstrated that autophagy is an important regulator of innate immune response. However, the mechanism by which autophagy regulates natural killer (NK) cell-mediated antitumor immune responses remains elusive. Here, we demonstrate that hypoxia impairs breast cancer cell susceptibility to NK-mediated lysis in vitro via the activation of autophagy. This impairment was not related to a defect in target cell recognition by NK cells but to the degradation of NK-derived granzyme B in autophagosomes of hypoxic cells. Inhibition of autophagy by targeting beclin1 (BECN1) restored granzyme B levels in hypoxic cells in vitro and induced tumor regression in vivo by facilitating NK-mediated tumor cell killing. Together, our data highlight autophagy as a mechanism underlying the resistance of hypoxic tumor cells to NK-mediated lysis. The work presented here provides a cutting-edge advance in our understanding of the mechanism by which hypoxia-induced autophagy impairs NK-mediated lysis in vitro and paves the way for the formulation of more effective NK cell-based antitumor therapies.