Abstract P2-09-03: Updated efficacy of first or second-line pembrolizumab (pembro) plus capecitabine (cape) in metastatic triple negative breast cancer (mTNBC) and correlations with baseline lymphocyte and naïve CD4+ T-cell count

Background: In mTNBC, anti-PD-1/L1 monotherapy is most effective when administered early in the course of disease, with recent trials demonstrating overall response rates (ORR) of 23-26% in the first-line setting and 5-6% in later lines. This may reflect iatrogenic lymphopenia from preceding cytotoxic chemotherapy. Furthermore, curative-intent chemotherapy is associated with prolonged suppression of naïve CD4+ cells, a T-cell subset that may play a critical role in the generation of de novo anti-tumor immune responses. We present the final clinical results of a pilot study evaluating the safety and efficacy of combining pembrolizumab plus standard-of-care capecitabine in the first/second-line mTNBC setting. We also explore potential associations between clinical benefit and lymphopenia, preceding chemotherapy, and absolute naïve CD4+ counts.

Methods: In a pilot study, we evaluated the tolerability and preliminary efficacy of concurrent pembro (200mg IV q21 day) plus investigator-selected 1st/2nd line paclitaxel (80mg/m2 IV weekly) or oral cape (2,000mg BID, weekly 1 on/1 off). The primary endpoint was tolerability, defined as the proportion of subjects receiving >6 weeks concurrent therapy without dose discontinuation with toxicities reported per CTCAE v4.0. The secondary endpoint was 12-week objective response rate (ORR) by RECIST1.1. Exploratory endpoints included peripheral blood cell enumeration by real-time flow cytometry and routine clinical laboratory. Naïve CD4+ cells were defined as CD45+ CD3+ TCRab+ CD4+ CD45RA+ CCR7+. Here, we report the results of the pilot phase of the cape cohort (NCT02734290).

Results: Twelve of 14 subjects were treated in the first-line setting. All subjects (14/14, 100%) tolerated cape+pembro for >6 weeks, with toxicities consistent with monotherapy cape experience (diarrhea: grade I-II 50%, grade III 7%; hand-foot: grade I-II 71%) that improved with dose-reduction as needed. At 12 weeks, the ORR was 6/14 (42.9%), and the clinical benefit rate (ORR + stable disease) was 8/14 (57.1%). Depressed absolute lymphocyte count at baseline (ALC<1.0/uL: 33% CBR; ALC≥1.0/uL: 75% CBR) and recent exposure to cytotoxic chemotherapy (<6 months: 33% CBR; >6 months: 75% CBR) were associated with reduced clinical benefit. By flow cytometry, subjects experiencing clinical benefit had higher baseline absolute naïve CD4+ counts (average 283 cells/uL v. 93 cells/uL, p=.069).

Conclusions: This study met the primary endpoint of safety for cape plus pembro in mTNBC, with encouraging clinical activity. These data are supportive of further studies evaluating combination chemotherapy plus anti-PD-1/L1 mTNBC. We observed greater clinical benefit in subjects with non-suppressed ALC, less exposure to recent chemo, and higher baseline naïve CD4+ counts, suggesting that iatrogenic immunosuppression can impair response to immune checkpoint therapy in mTNBC. These findings should be confirmed in ongoing randomized trials of immune checkpoint +/- chemotherapy in mTNBC, and should be considered in the design of future clinical trials.

Citation Format: Page DB, Pucilowska J, Bennetts L, Kim I, Sanchez K, Martel M, Conlin A, Moxon N, Mellinger S, Acheson A, Kemmer K, Mitri Z, Vuky J, Ahn J, Abaya C, Manigault T, Basho R, Urba WJ, McArthur HL. Updated efficacy of first or second-line pembrolizumab (pembro) plus capecitabine (cape) in metastatic triple negative breast cancer (mTNBC) and correlations with baseline lymphocyte and naïve CD4+ T-cell count [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-03.

Development of a promising microbial platform for the production of dicarboxylic acids from biorenewable resources

BACKGROUND

As a sustainable industrial process, the production of dicarboxylic acids (DCAs), used as precursors of polyamides, polyesters, perfumes, plasticizers, lubricants, and adhesives, from vegetable oil has continuously garnered interest. Although the yeast Candida tropicalis has been used as a host for DCA production, additional strains are continually investigated to meet productivity thresholds and industrial needs. In this regard, the yeast Wickerhamiella sorbophila, a potential candidate strain, has been screened. However, the lack of genetic and physiological information for this uncommon strain is an obstacle that merits further research. To overcome this limitation, we attempted to develop a method to facilitate genetic recombination in this strain and produce high amounts of DCAs from methyl laurate using engineered W. sorbophila.

RESULTS

In the current study, we first developed efficient genetic engineering tools for the industrial application of W. sorbophila. To increase homologous recombination (HR) efficiency during transformation, the cell cycle of the yeast was synchronized to the S/G2 phase using hydroxyurea. The HR efficiency at POX1 and POX2 loci increased from 56.3% and 41.7%, respectively, to 97.9% in both cases. The original HR efficiency at URA3 and ADE2 loci was nearly 0% during the early stationary and logarithmic phases of growth, and increased to 4.8% and 25.6%, respectively. We used the developed tools to construct W. sorbophila UHP4, in which β-oxidation was completely blocked. The strain produced 92.5 g/l of dodecanedioic acid (DDDA) from methyl laurate over 126 h in 5-l fed-batch fermentation, with a productivity of 0.83 g/l/h.

CONCLUSIONS

Wickerhamiella sorbophila UHP4 produced more DDDA methyl laurate than C. tropicalis. Hence, we demonstrated that W. sorbophila is a powerful microbial platform for vegetable oil-based DCA production. In addition, by using the developed genetic engineering tools, this emerging yeast could be used for the production of a variety of fatty acid derivatives, such as fatty alcohols, fatty aldehydes, and ω-hydroxy fatty acids.

Using social media for patient-reported outcomes: A study of genital appearance and sexual function in adult bladder exstrophy patients

INTRODUCTION

There have been few prior studies on patient-centered outcomes of adults with bladder exstrophy; those performed have been single institution reviews. In collaboration with the Association for the Bladder Exstrophy Communities (ABeC) - an international support network for patients and families living with bladder exstrophy - an anonymous social media survey was performed of patient-reported genital appearance and erectile function.

OBJECTIVE

The study evaluated the Penile Perception Score (PPS) and the International Index of Erectile Function (IIEF-15) in adult men with bladder exstrophy. It was hypothesized that scores would be significantly lower than prior reported scores for men without the condition.

STUDY DESIGN

After review by an anonymous patient advocate volunteer, the ABeC performed an anonymous online survey using social media.

RESULTS

Adult men with bladder exstrophy reported PPS, and satisfaction with penile length and axis that were lower than prior published controls (n = 54, P < 0.05). Orgasmic function, sexual desire, and overall satisfaction were also lower (n = 46, P < 0.05). There was no difference in erectile function or intercourse satisfaction compared to controls. There was an association between PPS and erectile function, intercourse satisfaction, and overall satisfaction (P < 0.05) (Summary Fig.). Respondents identified urinary issues, genital appearance, and sexual function as the three main domains that warranted further research.

CONCLUSION

This study found that PPS and IIEF-15 were low in adult men with bladder exstrophy, and worse perception of genital appearance was associated with worse sexual satisfaction. Social media is a novel tool for patient-centered outcomes research, and continued collaboration with patients and patient advocate groups is vital.

Microcrystalline Cellulose for Delivery of Recombinant Protein-Based Antigen against Erysipelas in Mice

The study describes the development of a vaccine using microcrystalline cellulose (Avicel PH-101) as a delivery carrier of recombinant protein-based antigen against erysipelas. Recombinant SpaA, surface protective protein, from a gram-positive pathogen Erysipelothrix rhusiopathiae was fused to a cellulose-binding domain (CBD) from Trichoderma harzianum endoglucanase II through a S3N10 peptide. The fusion protein (CBD-SpaA) was expressed in Escherichia coli and was subsequently bound to Avicel PH-101. The antigenicity of CBD-SpaA bound to the Avicel was evaluated by enzyme-linked immunosorbent (ELISA) and confocal laser scanning microscope (CLSM) assays. For the examination of its immunogenicity, groups of mice were immunized with different constructs (soluble CBD-SpaA, Avicel coated with CBD-SpaA, whole bacterin of E. rhusiopathiae (positive control), and PBS (negative control)). In two weeks after immunization, mice were challenged with 1x107 CFU of E. rhusiopathiae and Avicel coated with CBD-SpaA induced protective immunity in mice. In conclusion, this study demonstrates the feasibility of microcrystalline cellulose as the delivery system of recombinant protein subunit vaccine against E. rhusiopathiae infection in mice.

Effect of decanoic acid and 10-hydroxydecanoic acid on the biotransformation of methyl decanoate to sebacic acid

Biotransformation of fatty acid methyl esters to dicarboxylic acids has attracted much attention in recent years; however, reports of sebacic acid production using such biotransformation remain few. The toxicity of decanoic acid is the main challenge for this process. Decane induction has been reported to be essential to activate the enzymes involved in the α,ω-oxidation pathway before initiating the biotransformation of methyl decanoate to sebacic acid. However, we observed the accumulation of intermediates (decanoic acid and 10-hydroxydecanoic acid) during the induction period. In this study, we examined the effects of these intermediates on the biotransformation process. The presence of decanoic acid, even at a low concentration (0.2 g/L), inhibited the transformation of 10-hydroxydecanoic acid to sebacic acid. Moreover, about 24–32% reduction in the decanoic acid oxidation was observed in the presence of 0.5–1.5 g/L 10-hydroxydecanoic acid. To eliminate these inhibitory effects, we applied substrate-limiting conditions during the decane induction process, which eliminated the accumulation of decanoic acid. Although the productivity of sebacic acid (34.5 ± 1.10 g/L) was improved, by 28% over that achieved using the previously methods, after 54 h, the accumulation of 10-hydroxydecanoic acid was still detected. The accumulation of 10-hydroxydecanoic acid even under the decane limiting conditions could be an evidence that oxidation of 10-hydroxydecanoic acid could be the rate-limiting step in this process. The improvement of this reaction should be an important objective for further development of the production of sebacic acid using biotransformation.

The cytosolic sensor STING is required for intestinal homeostasis and control of inflammation

STING (stimulator of interferon genes) is a cytosolic sensor for cyclic dinucleotides and also an adaptor molecule for intracellular DNA receptors. Although STING has important functions in the host defense against pathogens and in autoimmune diseases, its physiological relevance in intestinal homeostasis is largely unknown. In this study, we show that STING^-/- mice presented defective protective mechanisms of intestinal mucosa, including decreased number of goblet cells, diminished mucus production, and lower levels of secretory IgA, when compared with wild-type (WT) mice. Fecal content and microbiota DNA could activate STING, indicating a role of this molecule in gut. Microbiota composition was altered in STING^-/- mice toward a more inflammatory profile, evidencing a reduction in the Allobacolum and Bifidobacterium groups along with increase in Disulfovibrio bacteria. Absence of STING lead to decrease in induced intraepithelial lymphocytes (IEL) and to increase in group 1 innate lymphoid cell (ILC1) as well as ILC3 frequencies and decrease in ILC2 in the colon. Development and function of Foxp3+ and LAP+ regulatory T cells were also compromised in STING^-/- mice. Moreover, these mice were highly susceptible to dextran sodium sulfate-induced colitis, T-cell-induced colitis, and enteric Salmonella typhimurium infection when compared with WT animals. Therefore, our results identify an important role of STING in maintaining gut homeostasis and also a protective effect in controlling gut inflammation.

Genetic Associations with Indoor Tanning Addiction

Some young people are prone to develop addiction to indoor tanning along with psychiatric comorbidity. This study examined genetic hypotheses that liabilities in neurobiological addiction reward pathways influence risk of indoor tanning addiction and are affected by psychiatric comorbidity. Methods: Data were from an observational study investigating factors associated with indoor tanning addiction in a community sample of non-Hispanic white women ages 18–30 years with a history of indoor tanning in the past year. A total of 295 participants completed self-report measures and provided DNA samples. DNA samples were genotyped and analyzed for 36 single nucleotide polymorphisms (SNPs) in candidate genes involved in hypothesized addiction reward pathways (e.g., opioid and dopamine receptor genes). Self-report measures included indoor tanning frequency and dependence symptoms, appearance beliefs, and depressive symptoms. Results: Over 20% of the sample screened positive for indoor tanning addiction. Two SNPs in the DRD2 dopamine receptor gene, rs4436578 and rs4648318, were significantly associated (P &lt; 0.05) with indoor tanning addiction after multiple testing adjustment using the false discovery rate. In logistic regression analyses adjusting for indoor tanning frequency, appearance beliefs, and depressive symptoms, homozygous major allele genotypes for both SNPs were associated with indoor tanning addiction (Odds Ratio [OR] 2.29, 95% Confidence Interval [CI] 1.11–4.77, and OR 1.95, 95% CI, 1.02–3.72, respectively). The major allele genotypes for both SNPs also interacted with depressive symptoms to influence the risk of indoor tanning addiction: OR 7.03, 95% CI, 3.26–15.19, OR 4.35, 95% CI, 2.06–9.20, respectively. Conclusions: This study is among the first to demonstrate SNPs in the DRD2 dopamine receptor gene are associated with indoor tanning addiction. Our findings demonstrate young women with risk-conferring genotypes and exhibiting depressive symptoms are at especially high risk. These data can inform personalized interventions tailored to neurobiological and behavioral differences to prevent melanoma and nonmelanoma skin cancer.

Associations between resistance phenotype and gene expression in response to serial exposure to oxacillin and ciprofloxacin in Staphylococcus aureus

This study was designed to delineate the relationship between resistance phenotypes and gene expression in wild-type (SA^WT ), oxacillin-induced (SA^OXA ), ciprofloxacin-induced (SA^CIP ) and clinically acquired antibiotic-resistant Staphylococcus aureus (SA^CA ) exposed to oxacillin (β-lactam) and ciprofloxacin (fluoroquinolone). The phenotypic response and gene expression were varied with the antibiotic exposure. SA^WT was highly resistant to oxacillin (MIC = 8 μg ml^-1 ) after serial exposure to oxacillin, while the oxacillin susceptibility was not changed in SA^WT when exposed to ciprofloxacin (MIC = 0·25 μg ml^-1 ). The clinical isolate, SA^CA , was highly resistant to all classes of antibiotics used in this study. The increased resistance of SA^OXA and SA^CIP to penicillinase-labile penicillins was attributed to the production of β-lactamase, which is in good agreement with the overexpression of blaZ (>2-fold). The overexpression of efflux pump-related genes (norA, norB, norC, mdeA, mepR, mgrA and lmrS) was associated with the increased resistance of SA^CIP and SA^CA to aminoglycosides and quinolones. This study confirmed that the linkage between resistance phenotypes and molecular genotypes highly varied depending on intrinsic resistance profile, response to antibiotic exposure and genes conferring resistance. This study provides useful information for understanding the mechanisms of methicillin resistance in S. aureus in association with phenotypic and genotypic resistance determinants.

SIGNIFICANCE AND IMPACT OF THE STUDY

The improvement in current standards is essential to accurately detect methicillin-resistant Staphylococcus aureus in consideration of various resistance phenotypes and genotypes. The varied and distinctive expression patterns of antibiotic resistance-related genes were observed in S. aureus exposed to oxacillin and ciprofloxacin. It is worth noting the relationship between resistance phenotype and resistance genotype in terms of MIC values and expression of antibiotic resistance determinants. This study provides useful information for understanding the mechanisms of methicillin resistance in S. aureus in association with phenotypic and genotypic resistance determinants.

Complete genome sequence of the sulfur-oxidizing chemolithoautotrophic Sulfurovum lithotrophicum 42BKTT

A sulfur-oxidizing chemolithoautotrophic bacterium, Sulfurovum lithotrophicum 42BKT^T, isolated from hydrothermal sediments in Okinawa, Japan, has been used industrially for CO₂ bio-mitigation owing to its ability to convert CO₂ into C₅H₈NO₄⁻ at a high rate of specific mitigation (0.42 g CO₂/cell/h). The genome of S. lithotrophicum 42BKT^T comprised of a single chromosome of 2217,891 bp with 2217 genes, including 2146 protein-coding genes and 54 RNA genes. Here, we present its complete genome-sequence information, including information about the genes encoding enzymes involved in CO₂ fixation and sulfur oxidation.

Hybrid polymer microfluidic platform to mimic varying vascular compliance and topology

Several cardiovascular pathologies and aging have been associated with alterations in the mechanical and structural properties of the vascular wall, leading to a reduction in arterial compliance and the development of constriction. In the past, rare efforts have been directed to understand the endothelial cell response to combined mechanical stimuli from fluid flow and substrate rigidity. Recent approaches using microfluidic platforms have limitations in precisely mimicking healthy and diseased vasculature conditions from altered topological and substrate compliance perspectives. To address this, we demonstrated an effective fabrication process to realize a hybrid polymer platform to test these mechanistic features of blood vessels. The salient features of the platform include circular microchannels of varying diameters, variation in substrate rigidity along the channel length, and the coexistence of microchannels with different cross sections on a single platform. The platform demonstrates the combined effects of flow-induced shear forces and substrate rigidity on the endothelial cell layer inside the circular microchannels. The experimental results indicate a pronounced cell response to flow induced shear stress via its interplay with the underlying substrate mechanics.

Characterization of the newly isolated ω-oxidizing yeast Candida sorbophila DS02 and its potential applications in long-chain dicarboxylic acid production

α, ω-Dicarboxylic acids (DCAs) are multipurpose chemicals widely used in polymers, perfumes, plasticizers, lubricants, and adhesives. The biotransformation of DCAs from alkanes and fatty acids by microorganisms has attracted recent interest, since synthesis via chemical oxidation causes problems in terms of the environment and safety. We isolated an ω-oxidizing yeast from a wastewater disposal facility of a petrochemical factory by chemostat enrichment culture. The haploid strain identified as Candida sorbophila DS02 grew on glucose and dodecane, exhibiting greater cell shrinkage on the latter. In flask cultures with mixed alkanes (C10-16) and fatty acid methyl esters (C10-16), DS02 used mixed alkanes simultaneously unlike Candida tropicalis and Yarrowia lipolytica and showed high substrate resistance. In flask cultures with acrylic acid-a known inhibitor of β-oxidation-DS02 produced 0.28 g/l dodecanedioic acid (DDDA) from dodecane, similar to wild-type C. tropicalis ATCC 20336. In fed-batch fermentation, DS02 produced 9.87 g/l DDDA, which was 5.7-fold higher than wild-type C. tropicalis. These results suggest that C. sorbophila strain DS02 has potential applications for the large-scale production of DCA.

Biomass-derived molecules modulate the behavior of Streptomyces coelicolor for antibiotic production

Various chemicals, i.e., furfural, vanillin, 4-hydroxybenzaldehyde and acetate produced during the pretreatment of biomass affect microbial fermentation. In this study, effect of vanillin, 4-hydroxybenzaldehyde and acetate on antibiotic production in Streptomyces coelicolor is investigated. IC₅₀ value of vanillin, 4-hydroxybenzaldehyde and acetate was recorded as 5, 11.3 and 115 mM, respectively. Vanillin was found as a very effective molecule, and it completely abolished antibiotic (undecylprodigiosin and actinorhodin) production at 1 mM concentration, while 4-hydroxybenzaldehyde and acetate have little effect. Microscopic analysis with field emission scanning electron microscopy (FESEM) showed that addition of vanillin inhibits mycelia formation and increases differentiation of S. coelicolor cells. Vanillin increases expression of genes responsible for sporulation (ssgA) and decreases expression of antibiotic transcriptional regulator (redD and actII-orf4), while it has no effect on genes related to the mycelia formation (bldA and bldN) and quorum sensing (scbA and scbR). Vanillin does not affect the glycolysis process, but may affect acetate and pyruvate accumulation which leads to increase in fatty acid accumulation. The production of antibiotics using biomass hydrolysates can be quite complex due to the presence of exogenous chemicals such as furfural and vanillin, and needs further detailed study.

Developing new automated alternation flicker using optic disc photography for the detection of glaucoma progression

PurposeTo evaluate a progression-detecting algorithm for a new automated matched alternation flicker (AMAF) in glaucoma patients.MethodsOpen-angle glaucoma patients with a baseline mean deviation of visual field (VF) test>-6 dB were included in this longitudinal and retrospective study. Functional progression was detected by two VF progression criteria and structural progression by both AMAF and conventional comparison methods using optic disc and retinal nerve fiber layer (RNFL) photography. Progression-detecting performances of AMAF and the conventional method were evaluated by an agreement between functional and structural progression criteria. RNFL thickness changes measured by optical coherence tomography (OCT) were compared between progressing and stable eyes determined by each method.ResultsAmong 103 eyes, 47 (45.6%), 21 (20.4%), and 32 (31.1%) eyes were evaluated as glaucoma progression using AMAF, the conventional method, and guided progression analysis (GPA) of the VF test, respectively. The AMAF showed better agreement than the conventional method, using GPA of the VF test (κ=0.337; P<0.001 and κ=0.124; P=0.191, respectively). The rates of RNFL thickness decay using OCT were significantly different between the progressing and stable eyes when progression was determined by AMAF (-3.49±2.86 μm per year vs -1.83±3.22 μm per year; P=0.007) but not by the conventional method (-3.24±2.42 μm per year vs -2.42±3.33 μm per year; P=0.290).ConclusionsThe AMAF was better than the conventional comparison method in discriminating structural changes during glaucoma progression, and showed a moderate agreement with functional progression criteria.