Stabilizing tumor resident mast cells restores T cell infiltration and sensitizes sarcomas to PD-L1 inhibition

PURPOSE

To explore the cellular crosstalk of tumor resident mast cells (MCs) in controlling the activity of cancer-associated fibroblasts (CAFs) to overcome TME abnormalities, enhancing the efficacy of immune checkpoint inhibitors (ICIs) in sarcoma.

EXPERIMENTAL DESIGN

We used a coculture system followed by further validation in mouse models of fibrosarcoma and osteosarcoma with or without administration of the MC stabilizer and antihistamine ketotifen. To evaluate the contribution of ketotifen in sensitizing tumors to therapy, we performed combination studies with doxorubicin chemotherapy and anti-PD-L1 (B7-H1, clone 10F.9G2) treatment. We investigated the ability of ketotifen to modulate the TME in human sarcomas in the context of a repurpose phase II clinical trial.

RESULTS

Inhibition of MC activation with ketotifen successfully suppressed CAF proliferation and stiffness of the extracellular matrix accompanied by an increase in vessel perfusion in fibrosarcoma and osteosarcoma as indicated by ultrasound shear wave elastography imaging. The improved tissue oxygenation increased the efficacy of chemo-immunotherapy, supported by enhanced T cell infiltration and acquisition of tumor antigen-specific memory. Importantly, the effect of ketotifen in reducing tumor stiffness was further validated in sarcoma patients highlighting its translational potential.

CONCLUSIONS

Our study suggests the targeting of MCs with clinically administered drugs, such as antihistamines, as a promising approach to overcome resistance to immunotherapy in sarcomas.

Relationships between physical and immunological tumor microenvironment in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is physically palpated as a hard tumor with an unfavorable prognosis. Assessing physical features and their association with pathological features could help to elucidate the mechanism of physical abnormalities in cancer tissues. A total of 93 patients who underwent radical surgery for pancreatic and bile duct cancers at a single center hospital during a 28-month period were recruited for this study that aimed to estimate the stiffness of PDAC tissues compared to the other neoplasms and assess relationships between tumor stiffness and pathological features. Physical alterations and pathological features of PDAC, with or without preoperative therapy, were analyzed. The immunological tumor microenvironment was evaluated using multiplexed fluorescent immunohistochemistry. The stiffness of PDAC correlated with the ratio of Azan-Mallory staining, α-smooth muscle actin, and collagen I-positive areas of the tumors. Densities of CD8+ T cells and CD204+ macrophages were associated with tumor stiffness in cases without preoperative therapy. Pancreatic ductal adenocarcinoma treated with preoperative therapy was softer than that without, and the association between tumor stiffness and immune cell infiltration was not shown after preoperative therapy. We observed the relationship between tumor stiffness and immunological features in human PDAC for the first time. Immune cell densities in the tumor center were smaller in hard tumors than in soft tumors without preoperative therapies. Preoperative therapy could alter physical and immunological aspects, warranting further study. Understanding of the correlations between physical and immunological aspects could lead to the development of new therapies.

Ultrasound stiffness and perfusion markers correlate with tumor volume responses to immunotherapy

Immunotherapy has revolutionized the treatment of dozens of cancers and became a standard of care for some tumor types. However, the majority of patients do not benefit from current immunotherapeutics and many develop severe toxicities. Therefore, the identification of biomarkers to classify patients as likely responders or non-responders to immunotherapy is a timely task. Here, we test ultrasound imaging markers of tumor stiffness and perfusion. Ultrasound imaging is non-invasive and clinically available and can be used both for stiffness and perfusion evaluation. In this study, we employed syngeneic orthotopic models of two breast cancers, a fibrosarcoma and melanoma, to demonstrate that ultrasound-derived measures of tumor stiffness and perfusion (i.e., blood volume) correlate with the efficacy of immune checkpoint inhibition (ICI) in terms of changes in primary tumor volume. To modulate tumor stiffness and perfusion and thus, get a range of therapeutic outcomes, we employed the mechanotherapeutic tranilast. Mechanotherapeutics combined with ICI are advancing through clinical trials, but biomarkers of response have not been tested until now. We found the existence of linear correlations between tumor stiffness and perfusion imaging biomarkers as well as strong linear correlations between the stiffness and perfusion markers with ICI efficacy on primary tumor growth rates. Our findings set the basis for ultrasound imaging biomarkers predictive of ICI therapy in combination with mechanotherapeutics. STATEMENT OF SIGNIFICANCE: Hypothesis: Monitoring Tumor Microenvironment (TME) mechanical abnormalities can predict the efficacy of immune checkpoint inhibition (ICI) and provide biomarkers predictive of response. Tumor stiffening and solid stress elevation are hallmarks of tumor patho-physiology in desmoplastic tumors. They induce hypo-perfusion and hypoxia by compressing tumor vessels, posing major barriers to immunotherapy. Mechanotherapeutics is a new class of drugs that target the TME to reduce stiffness and improve perfusion and oxygenation. In this study, we show that measures of stiffness and perfusion derived from ultrasound shear wave elastography and contrast enhanced ultrasound can provide biomarkers of tumor response.

Polymeric micelles effectively reprogram the tumor microenvironment to potentiate nano-immunotherapy in mouse breast cancer models

Nano-immunotherapy improves breast cancer outcomes but not all patients respond and none are cured. To improve efficacy, research focuses on drugs that reprogram cancer-associated fibroblasts (CAFs) to improve therapeutic delivery and immunostimulation. These drugs, however, have a narrow therapeutic window and cause adverse effects. Developing strategies that increase CAF-reprogramming while limiting adverse effects is urgent. Here, taking advantage of the CAF-reprogramming capabilities of tranilast, we developed tranilast-loaded micelles. Strikingly, a 100-fold reduced dose of tranilast-micelles induces superior reprogramming compared to free drug owing to enhanced intratumoral accumulation and cancer-associated fibroblast uptake. Combination of tranilast-micelles and epirubicin-micelles or Doxil with immunotherapy increases T-cell infiltration, resulting in cures and immunological memory in mice bearing immunotherapy-resistant breast cancer. Furthermore, shear wave elastography (SWE) is able to monitor reduced tumor stiffness caused by tranilast-micelles and predict response to nano-immunotherapy. Micellar encapsulation is a promising strategy for TME-reprogramming and SWE is a potential biomarker of response.

Multiphoton Phosphorescence Quenching Microscopy Reveals Kinetics of Tumor Oxygenation during Antiangiogenesis and Angiotensin Signaling Inhibition

PURPOSE

The abnormal function of tumor blood vessels causes tissue hypoxia, promoting disease progression and treatment resistance. Although tumor microenvironment normalization strategies can alleviate hypoxia globally, how local oxygen levels change is not known because of the inability to longitudinally assess vascular and interstitial oxygen in tumors with sufficient resolution. Understanding the spatial and temporal heterogeneity should help improve the outcome of various normalization strategies.

EXPERIMENTAL DESIGN

We developed a multiphoton phosphorescence quenching microscopy system using a low-molecular-weight palladium porphyrin probe to measure perfused vessels, oxygen tension, and their spatial correlations in vivo in mouse skin, bone marrow, and four different tumor models. Further, we measured the temporal and spatial changes in oxygen and vessel perfusion in tumors in response to an anti-VEGFR2 antibody (DC101) and an angiotensin-receptor blocker (losartan).

RESULTS

We found that vessel function was highly dependent on tumor type. Although some tumors had vessels with greater oxygen-carrying ability than those of normal skin, most tumors had inefficient vessels. Further, intervessel heterogeneity in tumors is associated with heterogeneous response to DC101 and losartan. Using both vascular and stromal normalizing agents, we show that spatial heterogeneity in oxygen levels persists, even with reductions in mean extravascular hypoxia.

CONCLUSIONS

High-resolution spatial and temporal responses of tumor vessels to two agents known to improve vascular perfusion globally reveal spatially heterogeneous changes in vessel structure and function. These dynamic vascular changes should be considered in optimizing the dose and schedule of vascular and stromal normalizing strategies to improve the therapeutic outcome.

Histological tumor necrosis in pancreatic cancer after neoadjuvant therapy

The pathological prognostic factors in pancreatic cancer patients who have received neoadjuvant therapy (NAT) are still elusive. The aim of the present study was to investigate the prognostic potential of histological tumor necrosis (HTN) in patients who received NAT and to evaluate tumor changes after NAT. HTN was studied in 44 pancreatic cancer patients who received NAT followed by surgery (NAT group) compared with 263 patients who received upfront surgery (UFS group). The prognostic factors in the NAT group were analyzed, and carbonic anhydrase 9 (CA‑9) expression was compared between the NAT and USF group to evaluate the hypoxic microenvironment changes during NAT. HTN was found in 15 of 44 patients in the NAT group, and its frequency was lower than that in the UFS group (34 vs. 51%, P=0.04). Cox proportional hazards models identified HTN as an independent risk factor for relapse‑free survival in the NAT group [risk ratio (RR), 5.60; 95% confidence interval (CI): 2.27‑14.26, P<0.01]. Significant correlations were found between HTN and CA‑9 expression both in the NAT and UFS groups (P<0.01 for both). CA‑9 expression was significantly upregulated in the NAT group overall, although this upregulation was specifically induced in patients without HTN. In conclusion, HTN was a poor prognostic factor in pancreatic cancer patients receiving NAT followed by surgery, and the present study suggests a close association between HTN and tumor hypoxia. Increased hypoxia after NAT may support the thesis for re‑engineering the hypoxia‑alleviating tumor microenvironment in NAT regimens for pancreatic cancer.

Towards Immunotherapy-Induced Normalization of the Tumor Microenvironment

Immunotherapies modulate the function of immune cells to eradicate cancer cells through various mechanisms. These therapies are successful across a spectrum of cancers, but they are curative only in a subset of patients. Indeed, a major obstacle to the success of immunotherapies is the immunosuppressive nature of the tumor microenvironment (TME), comprising the stromal component and immune infiltrate of tumors. Importantly, the TME in most solid cancers is characterized by sparsely perfused blood vessels resulting from so-called pathological angiogenesis. In brief, dysregulated development of new vessels results in leaky tumor blood vessels that inefficiently deliver oxygen and other nutrients. Moreover, the occurrence of dysregulated fibrosis around the lesion, known as pathological desmoplasia, further compresses tumor blood vessels and impairs blood flow. TME normalization is a clinically tested treatment strategy to reverse these tumor blood vessel abnormalities resulting in stimulated antitumor immunity and enhanced immunotherapy efficacy. TME normalization includes vascular normalization to reduce vessel leakiness and reprogramming of cancer-associated fibroblast to decompress vessels. How immunotherapies themselves normalize the TME is poorly understood. In this review, we summarize current concepts and progress in TME normalization. Then, we review observations of immunotherapy-induced TME normalization and discuss the considerations for combining vascular normalizing and immunotherapies. If TME could be more completely normalized, immunotherapies could be more effective in more patients.

Abstract 6382: Targeting mast cells restores T cell infiltration and sensitizes sarcomas to PD-L1 inhibition

Despite recent advances in cancer research, developments in sarcoma treatment have been slow. The efficacy of chemotherapy in sarcoma is limited by the pathophysiology of surrounding tumor stroma. Abnormalities in the tumor microenvironment (TME) result in stiffening of the tumor and accumulation of mechanical stresses which in turn cause the extreme deformation and collapse of intratumoral vessels. Strategies to induce TME reprogramming with the aim to restore mechanical properties of the tissue as well as tumor blood vessel functionality involve the use of “mechanotherapeutics”. Herein, we exploited the potential of the antihistamine drug and mast cell stabilizer, ketotifen, to induce mechanotherapeutic effects in murine models of soft tissue and bone sarcoma. Mast cells are the first population of immune cells drawn to the tumorigenic nidus where they interact with multiple components of the TME. Yet, their role in tumor stroma remains enigmatic as they either promote or inhibit tumor development depending on the conditions. In agreement with other mechanotherapeutics, we found that ketotifen induces vascular normalization in a dose dependent manner as indicated by the increase in perfusion, higher open lumen fraction and pericyte coverage of the vessels. Moreover, in vivo ultrasound shear wave elastography confirmed the mechanotherapeutic properties of ketotifen in reducing tissue stiffness, while further ex vivo validation indicated that TME reprogramming is mediated by a significant reduction in cancer associated fibroblast and inhibition of collagen synthesis as well as of that of other extracellular matrix components. Furthermore, we found that ketotifen modulates the immune microenvironment to promote immunostimulation. Immune stimulation was mediated by both intratumoral T cell accumulation and higher cytotoxic to regulatory T cell ratio concomitantly with a pronounced reduction in tissue hypoxia and upregulation of leukocyte adhesion molecules on endothelium. As a result of ketotifen-induced TME reprogramming, the addition of ketotifen to doxorubicin-aPDL1 combination treatment exhibited therapeutic superiority as opposed to doxorubicin-aPDL1, offering a durable tumor remission and immunological memory following tumor rechallenge experiments. Taken together, our findings demonstrate that ketotifen has a dual role in shaping the TME: i) reducing intratumoral physical forces to improve perfusion and ii) establishing favorable immunogenic conditions. Therefore, incorporating such agents in clinical practice holds great promise in the treatment of refractory, advanced sarcomas.

Citation Format: Myrofora Panagi, Fotios Mpekris, Chrysovalantis Voutouri, Christina Michael, Anastasia Constantinidou, John D. Martin, Triantafyllos Stylianopoulos. Targeting mast cells restores T cell infiltration and sensitizes sarcomas to PD-L1 inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6382.

Modeling the onset of symptoms of COVID-19: Effects of SARS-CoV-2 variant

Identifying order of symptom onset of infectious diseases might aid in differentiating symptomatic infections earlier in a population thereby enabling non-pharmaceutical interventions and reducing disease spread. Previously, we developed a mathematical model predicting the order of symptoms based on data from the initial outbreak of SARS-CoV-2 in China using symptom occurrence at diagnosis and found that the order of COVID-19 symptoms differed from that of other infectious diseases including influenza. Whether this order of COVID-19 symptoms holds in the USA under changing conditions is unclear. Here, we use modeling to predict the order of symptoms using data from both the initial outbreaks in China and in the USA. Whereas patients in China were more likely to have fever before cough and then nausea/vomiting before diarrhea, patients in the USA were more likely to have cough before fever and then diarrhea before nausea/vomiting. Given that the D614G SARS-CoV-2 variant that rapidly spread from Europe to predominate in the USA during the first wave of the outbreak was not present in the initial China outbreak, we hypothesized that this mutation might affect symptom order. Supporting this notion, we found that as SARS-CoV-2 in Japan shifted from the original Wuhan reference strain to the D614G variant, symptom order shifted to the USA pattern. Google Trends analyses supported these findings, while weather, age, and comorbidities did not affect our model's predictions of symptom order. These findings indicate that symptom order can change with mutation in viral disease and raise the possibility that D614G variant is more transmissible because infected people are more likely to cough in public before being incapacitated with fever.

Remodeling tumor microenvironment with nanomedicines

The tumor microenvironment (TME) has been recognized as a major contributor to cancer malignancy and therapeutic resistance. Thus, strategies directed to re-engineer the TME are emerging as promising approaches for improving the efficacy of antitumor therapies by enhancing tumor perfusion and drug delivery, as well as alleviating the immunosuppressive TME. In this regard, nanomedicine has shown great potential for developing effective treatments capable of re-modeling the TME by controlling drug action in a spatiotemporal manner and allowing long-lasting modulatory effects on the TME. Herein, we review recent progress on TME re-engineering by using nanomedicine, particularly focusing on formulations controlling TME characteristics through targeted interaction with cellular components of the TME. Importantly, the TME should be re-engineering to a quiescent phenotype rather than be destroyed. Finally, immediate challenges and future perspectives of TME-re-engineering nanomedicines are discussed, anticipating further innovation in this growing field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Normalizing the Microenvironment Overcomes Vessel Compression and Resistance to Nano-immunotherapy in Breast Cancer Lung Metastasis

Nano-immunotherapy regimens have high potential to improve patient outcomes, as already demonstrated in advanced triple negative breast cancer with nanoparticle albumin-bound paclitaxel and the immune checkpoint blocker (ICB) atezolizumab. This regimen, however, does not lead to cures with median survival lasting less than two years. Thus, understanding the mechanisms of resistance to and development of strategies to enhance nano-immunotherapy in breast cancer are urgently needed. Here, in human tissue it is shown that blood vessels in breast cancer lung metastases are compressed leading to hypoxia. This pathophysiology exists in murine spontaneous models of triple negative breast cancer lung metastases, along with low levels of perfusion. Because this pathophysiology is consistent with elevated levels of solid stress, the mechanotherapeutic tranilast, which decompressed lung metastasis vessels, is administered to mice bearing metastases, thereby restoring perfusion and alleviating hypoxia. As a result, the nanomedicine Doxil causes cytotoxic effects into metastases more efficiently, stimulating anti-tumor immunity. Indeed, when combining tranilast with Doxil and ICBs, synergistic effects on efficacy, with all mice cured in one of the two ICB-insensitive tumor models investigated is resulted. These results suggest that strategies to treat breast cancer with nano-immunotherapy should also include a mechanotherapeutic to decompress vessels.

Self-Performed Lung Ultrasound for Home Monitoring of a Patient Positive for Coronavirus Disease 2019

A subset of patients with coronavirus disease 2019 (COVID-19) and lung involvement pose a disposition challenge, particularly when hospital resources are constrained. Those not in respiratory failure are sent home, often with phone monitoring and/or respiratory rate and oxygen saturation monitoring. Hypoxemia may be a late presentation and is often preceded by abnormal lung findings on ultrasound. Early identification of pulmonary progression may preempt emergency hospitalization for respiratory decompensation and facilitate more timely admission. With the goal of safely isolating infected patients while providing advanced monitoring, we present a first report of patient self-performed lung ultrasound in the home with a hand-held device under the guidance of a physician using a novel teleguidance platform.

Modeling the Onset of Symptoms of COVID-19

COVID-19 is a pandemic viral disease with catastrophic global impact. This disease is more contagious than influenza such that cluster outbreaks occur frequently. If patients with symptoms quickly underwent testing and contact tracing, these outbreaks could be contained. Unfortunately, COVID-19 patients have symptoms similar to other common illnesses. Here, we hypothesize the order of symptom occurrence could help patients and medical professionals more quickly distinguish COVID-19 from other respiratory diseases, yet such essential information is largely unavailable. To this end, we apply a Markov Process to a graded partially ordered set based on clinical observations of COVID-19 cases to ascertain the most likely order of discernible symptoms (i.e., fever, cough, nausea/vomiting, and diarrhea) in COVID-19 patients. We then compared the progression of these symptoms in COVID-19 to other respiratory diseases, such as influenza, SARS, and MERS, to observe if the diseases present differently. Our model predicts that influenza initiates with cough, whereas COVID-19 like other coronavirus-related diseases initiates with fever. However, COVID-19 differs from SARS and MERS in the order of gastrointestinal symptoms. Our results support the notion that fever should be used to screen for entry into facilities as regions begin to reopen after the outbreak of Spring 2020. Additionally, our findings suggest that good clinical practice should involve recording the order of symptom occurrence in COVID-19 and other diseases. If such a systemic clinical practice had been standard since ancient diseases, perhaps the transition from local outbreak to pandemic could have been avoided.

Normalizing Function of Tumor Vessels: Progress, Opportunities, and Challenges

Abnormal blood and lymphatic vessels create a hostile tumor microenvironment characterized by hypoxia, low pH, and elevated interstitial fluid pressure. These abnormalities fuel tumor progression, immunosuppression, and treatment resistance. In 2001, we proposed a novel hypothesis that the judicious use of antiangiogenesis agents-originally developed to starve tumors-could transiently normalize tumor vessels and improve the outcome of anticancer drugs administered during the window of normalization. In addition to providing preclinical and clinical evidence in support of this hypothesis, we also revealed the underlying molecular mechanisms. In parallel, we demonstrated that desmoplasia could also impair vascular function by compressing vessels, and that normalizing the extracellular matrix could improve vascular function and treatment outcome in both preclinical and clinical settings. Here, we summarize the progress made in understanding and applying the normalization concept to cancer and outline opportunities and challenges ahead to improve patient outcomes using various normalizing strategies.

Improving cancer immunotherapy using nanomedicines: progress, opportunities and challenges

Multiple nanotherapeutics have been approved for patients with cancer, but their effects on survival have been modest and, in some examples, less than those of other approved therapies. At the same time, the clinical successes achieved with immunotherapy have revolutionized the treatment of multiple advanced-stage malignancies. However, the majority of patients do not benefit from the currently available immunotherapies and many develop immune-related adverse events. By contrast, nanomedicines can reduce - but do not eliminate - the risk of certain life-threatening toxicities. Thus, the combination of these therapeutic classes is of intense research interest. The tumour microenvironment (TME) is a major cause of the failure of both nanomedicines and immunotherapies that not only limits delivery, but also can compromise efficacy, even when agents accumulate in the TME. Coincidentally, the same TME features that impair nanomedicine delivery can also cause immunosuppression. In this Perspective, we describe TME normalization strategies that have the potential to simultaneously promote the delivery of nanomedicines and reduce immunosuppression in the TME. Then, we discuss the potential of a combined nanomedicine-based TME normalization and immunotherapeutic strategy designed to overcome each step of the cancer-immunity cycle and propose a broadly applicable 'minimal combination' of therapies designed to increase the number of patients with cancer who are able to benefit from immunotherapy.

Gas Chromatographic Determination of Volatile Congeners in Spirit Drinks: Interlaboratory Study

An interlaboratory study of a gas chromatographic (GC) method for the determination of volatile congeners in spirit drinks was conducted; 31 laboratories from 8 countries took part in the study. The method uses GC with flame ionization detection and incorpo rates several quality control measures which permit the choice of chromatographic system and conditions to be selected by the user. Spirit drink samples were prepared and sent to participants as 10 blind duplicate or split-level test materials for the determination of 1,1-diethoxyethane (acetal), 2-methylbutan-1-ol (active amyl alcohol), 3-methylbutan-1-ol (isoamyl alcohol), methanol (methyl alcohol), ethyl ethanoate (ethyl acetate), butan-1-ol (n-butanol), butan-2-ol (sec-butanol), 2-methylpropan-1-ol(isobutyl alcohol), propan-1-ol (n-propanol), and ethanal (acetaldehyde). The precision of the method for 9 of the 10 analytes was well within the range predicted by the Horwitz equation.The precision of the most volatile analyte, ethanal, was just above statistically predicted levels. This method is recommended for official regulatory purposes.

TGF-β inhibition combined with cytotoxic nanomedicine normalizes triple negative breast cancer microenvironment towards anti-tumor immunity

Tumor normalization strategies aim to improve tumor blood vessel functionality (i.e., perfusion) by reducing the hyper-permeability of tumor vessels or restoring compressed vessels. Despite progress in strategies to normalize the tumor microenvironment (TME), their combinatorial antitumor effects with nanomedicine and immunotherapy remain unexplored. Methods: Here, we re-purposed the TGF-β inhibitor tranilast, an approved anti-fibrotic and antihistamine drug, and combined it with Doxil nanomedicine to normalize the TME, increase perfusion and oxygenation, and enhance anti-tumor immunity. Specifically, we employed two triple-negative breast cancer (TNBC) mouse models to primarily evaluate the therapeutic and normalization effects of tranilast combined with doxorubicin and Doxil. We demonstrated the optimized normalization effects of tranilast combined with Doxil and extended our analysis to investigate the effect of TME normalization to the efficacy of immune checkpoint inhibitors. Results: Combination of tranilast with Doxil caused a pronounced reduction in extracellular matrix components and an increase in the intratumoral vessel diameter and pericyte coverage, indicators of TME normalization. These modifications resulted in a significant increase in tumor perfusion and oxygenation and enhanced treatment efficacy as indicated by the notable reduction in tumor size. Tranilast further normalized the immune TME by restoring the infiltration of T cells and increasing the fraction of T cells that migrate away from immunosuppressive cancer-associated fibroblasts. Furthermore, we found that combining tranilast with Doxil nanomedicine, significantly improved immunostimulatory M1 macrophage content in the tumorigenic tissue and improved the efficacy of the immune checkpoint blocking antibodies anti-PD-1/anti-CTLA-4. Conclusion: Combinatorial treatment of tranilast with Doxil optimizes TME normalization, improves immunostimulation and enhances the efficacy of immunotherapy.

Dexamethasone Increases Cisplatin-Loaded Nanocarrier Delivery and Efficacy in Metastatic Breast Cancer by Normalizing the Tumor Microenvironment

Dexamethasone is a glucocorticoid steroid with anti-inflammatory properties used to treat many diseases, including cancer, in which it helps manage various side effects of chemo-, radio-, and immunotherapies. Here, we investigate the tumor microenvironment (TME)-normalizing effects of dexamethasone in metastatic murine breast cancer (BC). Dexamethasone normalizes vessels and the extracellular matrix, thereby reducing interstitial fluid pressure, tissue stiffness, and solid stress. In turn, the penetration of 13 and 32 nm dextrans, which represent nanocarriers (NCs), is increased. A mechanistic model of fluid and macromolecule transport in tumors predicts that dexamethasone increases NC penetration by increasing interstitial hydraulic conductivity without significantly reducing the effective pore diameter of the vessel wall. Also, dexamethasone increases the tumor accumulation and efficacy of ∼30 nm polymeric micelles containing cisplatin (CDDP/m) against murine models of primary BC and spontaneous BC lung metastasis, which also feature a TME with abnormal mechanical properties. These results suggest that pretreatment with dexamethasone before NC administration could increase efficacy against primary tumors and metastases.

The hidden heritage of Arab libraries: Online catalogs and institutional barriers to discoverability

Advances in technology have made access to information about library holdings a seemingly universal feature of interaction with modern libraries. However, this type of access does not exist evenly throughout the world. There is a vast “hidden heritage” contained in Arab libraries without online public access catalogs. This article reports and summarizes findings from research conducted as part of a year-long investigation into international library collaboration in Arab libraries. The research included: (a) a survey of online presence for Arab libraries, (b) a survey of Arab librarians, and (c) focused panel discussions with Arab librarians and library scholars. This study finds that the relatively small online presence of libraries cannot be explained by material factors alone: institutional factors also play an important role in keeping information about library collections offline.

Anti-VEGF therapy induces ECM remodeling and mechanical barriers to therapy in colorectal cancer liver metastases

The survival benefit of anti-vascular endothelial growth factor (VEGF) therapy in metastatic colorectal cancer (mCRC) patients is limited to a few months because of acquired resistance. We show that anti-VEGF therapy induced remodeling of the extracellular matrix with subsequent alteration of the physical properties of colorectal liver metastases. Preoperative treatment with bevacizumab in patients with colorectal liver metastases increased hyaluronic acid (HA) deposition within the tumors. Moreover, in two syngeneic mouse models of CRC metastasis in the liver, we show that anti-VEGF therapy markedly increased the expression of HA and sulfated glycosaminoglycans (sGAGs), without significantly changing collagen deposition. The density of these matrix components correlated with increased tumor stiffness after anti-VEGF therapy. Treatment-induced tumor hypoxia appeared to be the driving force for the remodeling of the extracellular matrix. In preclinical models, we show that enzymatic depletion of HA partially rescued the compromised perfusion in liver mCRCs after anti-VEGF therapy and prolonged survival in combination with anti-VEGF therapy and chemotherapy. These findings suggest that extracellular matrix components such as HA could be a potential therapeutic target for reducing physical barriers to systemic treatments in patients with mCRC who receive anti-VEGF therapy.

Reengineering the Tumor Microenvironment to Alleviate Hypoxia and Overcome Cancer Heterogeneity

Solid tumors consist of cancer cells and stromal cells, including resident and transiting immune cells-all ensconced in an extracellular matrix (ECM)-nourished by blood vessels and drained by lymphatic vessels. The microenvironment constituents are abnormal and heterogeneous in morphology, phenotype, and physiology. Such irregularities include an inefficient tumor vascular network comprised of leaky and compressed vessels, which impair blood flow and oxygen delivery. Low oxygenation in certain tumor regions-or focal hypoxia-is a mediator of cancer progression, metastasis, immunosuppression, and treatment resistance. Thus, repairing an abnormal and heterogeneous microenvironment-and hypoxia in particular-can significantly improve treatments of solid tumors. Here, we summarize two strategies to reengineer the tumor microenvironment (TME)-vessel normalization and decompression-that can alleviate hypoxia. In addition, we discuss how these two strategies alone and in combination with each other-or other therapeutic strategies-may overcome the challenges posed by cancer heterogeneity.

A Study of the Relationship between a Personal Philosophy of Human Nature (Good or Evil) and Self-Esteem

The present study was undertaken to estimate the relationship between a personal philosophy of human nature (whether man is essentially good or evil) and an individual's self-esteem, as measured by the Coopersmith Self-esteem Inventory and the Self-esteem scale of the Jackson Personality Inventory. For 19 male and 21 female undergraduate students, correlations of age and sex with self-esteem were calculated. The multivariate analysis of variance indicated a nonsignificant relation between scores on philosophy of human nature of students and their scores on the two measures of self-esteem. Correlations of age and sex with self-esteem were also nonsignificant. The Coopersmith Self-esteem Inventory scores and those on the Self-esteem scale of the Jackson Personality Inventory were significantly correlated at .59.

Relationship of Scores on the California Psychological Inventory to Age

For a sample of 179 college students (18 to 69 yr. old), age was significantly correlated (.20 to .43) with the California Psychological Inventory scales of Dominance, Capacity for Status, Sociability, Sense of Well-being, Responsibility, Self-control, Tolerance, Good Impression, Achievement via Conformance, Achievement via Independence, Intellectual Efficiency, and Psychological-mindedness.

Correlations between Scores on Torrance Tests of Creative Thinking and Ingenuity Subtest of the Flanagan Aptitude Classification Tests

The twofold purpose of the present study was to determine the magnitude of relationship between the scores on the Torrance Tests of Creative Thinking and scores on the Ingenuity subtest of the Flanagan Aptitude Classification Tests and to determine the intercorrelations among Torrance Tests for 79 undergraduates, tested in groups. The Pearson product-moment correlations (—.19, largest r) indicated that the concepts of creativity and ingenuity are dissimilar.

A Study of the Relationship of Styles of Loving and Marital Happiness

In a study of the relationship of styles of loving and marital happiness the Marital Adjustment Test (Short-Form) and the Styles of Loving survey were mailed or hand delivered to 200 married couples in Hopkinsville, Kentucky and Clarksville, Tennessee, as well as to couples in the southeastern USA which included parts of Florida and Mississippi. For the 110 returns (55 couples) deemed suitable, a significant positive Pearson correlation of .58 between the wives' Agape (giving) style of loving and their husbands' marital happiness was obtained. If a wife's style of loving was Mania (selfish), a negative correlation (–.34) was obtained with her husband's marital happiness, but no significant correlation was noted between the men's styles of loving and wives' marital happiness.

Obesity-Induced Inflammation and Desmoplasia Promote Pancreatic Cancer Progression and Resistance to Chemotherapy

It remains unclear how obesity worsens treatment outcomes in patients with pancreatic ductal adenocarcinoma (PDAC). In normal pancreas, obesity promotes inflammation and fibrosis. We found in mouse models of PDAC that obesity also promotes desmoplasia associated with accelerated tumor growth and impaired delivery/efficacy of chemotherapeutics through reduced perfusion. Genetic and pharmacologic inhibition of angiotensin-II type-1 receptor reverses obesity-augmented desmoplasia and tumor growth and improves response to chemotherapy. Augmented activation of pancreatic stellate cells (PSC) in obesity is induced by tumor-associated neutrophils (TAN) recruited by adipocyte-secreted IL1β. PSCs further secrete IL1β, and inactivation of PSCs reduces IL1β expression and TAN recruitment. Furthermore, depletion of TANs, IL1β inhibition, or inactivation of PSCs prevents obesity-accelerated tumor growth. In patients with pancreatic cancer, we confirmed that obesity is associated with increased desmoplasia and reduced response to chemotherapy. We conclude that cross-talk between adipocytes, TANs, and PSCs exacerbates desmoplasia and promotes tumor progression in obesity.

SIGNIFICANCE

Considering the current obesity pandemic, unraveling the mechanisms underlying obesity-induced cancer progression is an urgent need. We found that the aggravation of desmoplasia is a key mechanism of obesity-promoted PDAC progression. Importantly, we discovered that clinically available antifibrotic/inflammatory agents can improve the treatment response of PDAC in obese hosts. Cancer Discov; 6(8); 852-69. ©2016 AACR.See related commentary by Bronte and Tortora, p. 821This article is highlighted in the In This Issue feature, p. 803.

Discovery of a Novel 2,6-Disubstituted Glucosamine Series of Potent and Selective Hexokinase 2 Inhibitors

A novel series of potent and selective hexokinase 2 (HK2) inhibitors, 2,6-disubstituted glucosamines, has been identified based on HTS hits, exemplified by compound 1. Inhibitor-bound crystal structures revealed that the HK2 enzyme could adopt an "induced-fit" conformation. The SAR study led to the identification of potent HK2 inhibitors, such as compound 34 with greater than 100-fold selectivity over HK1. Compound 25 inhibits in situ glycolysis in a UM-UC-3 bladder tumor cell line via (13)CNMR measurement of [3-(13)C]lactate produced from [1,6-(13)C2]glucose added to the cell culture.

Preclinical Efficacy of Ado-trastuzumab Emtansine in the Brain Microenvironment

BACKGROUND

Central nervous system (CNS) metastases represent a major problem in the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer because of the disappointing efficacy of HER2-targeted therapies against brain lesions. The antibody-drug conjugate ado-trastuzumab emtansine (T-DM1) has shown efficacy in trastuzumab-resistant systemic breast cancer. Here, we tested the hypothesis that T-DM1 could overcome trastuzumab resistance in murine models of brain metastases.

METHODS

We treated female nude mice bearing BT474 or MDA-MB-361 brain metastases (n = 9-11 per group) or cancer cells grown in organotypic brain slice cultures with trastuzumab or T-DM1 at equivalent or equipotent doses. Using intravital imaging, molecular techniques and histological analysis we determined tumor growth, mouse survival, cancer cell apoptosis and proliferation, tumor drug distribution, and HER2 signaling. Data were analyzed with one-way analysis of variance (ANOVA), Kaplan-Meier analysis, and Coefficient of Determination. All statistical tests were two-sided.

RESULTS

T-DM1 delayed the growth of HER2-positive breast cancer brain metastases compared with trastuzumab. These findings were consistent between HER2-driven and PI3K-driven tumors. The activity of T-DM1 resulted in a survival benefit (median survival for BT474 tumors: 28 days for trastuzumab vs 112 days for T-DM1, hazard ratio = 6.2, 95% confidence interval = 6.1 to 85.84, P < .001). No difference in drug distribution or HER2-signaling was revealed between the two groups. However, T-DM1 led to a statistically significant increase in tumor cell apoptosis (one-way ANOVA for ApopTag, P < .001), which was associated with mitotic catastrophe.

CONCLUSIONS

T-DM1 can overcome resistance to trastuzumab therapy in HER2-driven or PI3K-driven breast cancer brain lesions due to the cytotoxicity of the DM1 component. Clinical investigation of T-DM1 for patients with CNS metastases from HER2-positive breast cancer is warranted.

Abstract B19: Anti-VEGF treatment normalizes tuberculosis granuloma vasculature and improves small molecule delivery

Tuberculosis (TB) causes almost 2 million deaths annually, and an increasing number of patients are resistant to existing therapies. TB patients require lengthy chemotherapy, possibly because of poor penetration of antibiotics into granulomas where the bacilli reside. Granulomas are morphologically similar to solid cancerous tumors in that they contain hypoxic microenvironments and can be highly fibrotic. Here we show that TB-infected rabbits have impaired small molecule distribution into these disease sites due to a functionally abnormal vasculature, with a low molecular weight tracer accumulating only in peripheral regions of granulomatous lesions. Granuloma-associated vessels are morphologically and spatially heterogeneous, with poor vessel pericyte coverage in both human and experimental rabbit TB granulomas. Moreover, we found enhanced vascular endothelial growth factor (VEGF) expression in both species. In tumors, anti-angiogenic, specifically anti-VEGF, treatments can “normalize” their vasculature, reducing hypoxia and creating a window-of-opportunity for conjunctive chemotherapy; thus, we investigated vessel normalization in rabbit TB granulomas. Treatment of TB-infected rabbits with the anti-VEGF antibody bevacizumab significantly decreased the total number of vessels while normalizing those that remained. As a result, hypoxic fractions of these granulomas were reduced and small molecule tracer delivery increased. These findings demonstrate that bevacizumab treatment promotes vascular normalization, improves small molecule delivery, and decreases hypoxia in TB granulomas, thereby providing a potential new avenue to improve delivery and efficacy of current treatment regimens.

Citation Format: Meenal Datta, Laura E. Via, Walid S. Kamoun, Chong Liu, Wei Chen, Giorgio Seano, Danielle M. Weiner, Daniel Schimel, Kathleen England, John D. Martin, Xing Gao, Lei Xu, Clifton E. Barry, III, Rakesh K. Jain. Anti-VEGF treatment normalizes tuberculosis granuloma vasculature and improves small molecule delivery. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr B19.

The role of mechanical forces in tumor growth and therapy

Tumors generate physical forces during growth and progression. These physical forces are able to compress blood and lymphatic vessels, reducing perfusion rates and creating hypoxia. When exerted directly on cancer cells, they can increase cells' invasive and metastatic potential. Tumor vessels-while nourishing the tumor-are usually leaky and tortuous, which further decreases perfusion. Hypoperfusion and hypoxia contribute to immune evasion, promote malignant progression and metastasis, and reduce the efficacy of a number of therapies, including radiation. In parallel, vessel leakiness together with vessel compression causes a uniformly elevated interstitial fluid pressure that hinders delivery of blood-borne therapeutic agents, lowering the efficacy of chemo- and nanotherapies. In addition, shear stresses exerted by flowing blood and interstitial fluid modulate the behavior of cancer and a variety of host cells. Taming these physical forces can improve therapeutic outcomes in many cancers.

Effects of vascular-endothelial protein tyrosine phosphatase inhibition on breast cancer vasculature and metastatic progression

BACKGROUND

The solid tumor microvasculature is characterized by structural and functional abnormality and mediates several deleterious aspects of tumor behavior. Here we determine the role of vascular endothelial protein tyrosine phosphatase (VE-PTP), which deactivates endothelial cell (EC) Tie-2 receptor tyrosine kinase, thereby impairing maturation of tumor vessels.

METHODS

AKB-9778 is a first-in-class VE-PTP inhibitor. We examined its effects on ECs in vitro and on embryonic angiogenesis in vivo using zebrafish assays. We studied the impact of AKB-9778 therapy on the tumor vasculature, tumor growth, and metastatic progression using orthotopic models of murine mammary carcinoma as well as spontaneous and experimental metastasis models. Finally, we used endothelial nitric oxide synthase (eNOS)-deficient mice to establish the role of eNOS in mediating the effects of VE-PTP inhibition. All statistical tests were two-sided.

RESULTS

AKB-9778 induced ligand-independent Tie-2 activation in ECs and impaired embryonic zebrafish angiogenesis. AKB-9778 delayed the early phase of mammary tumor growth by maintaining vascular maturity (P < .01, t test); slowed growth of micrometastases (P < .01, χ(2) test) by preventing extravasation of tumor cells (P < 0.01, Fisher exact test), resulting in a trend toward prolonged survival (27.0 vs 36.5 days; hazard ratio of death = 0.33, 95% confidence interval = 0.11 to 1.03; P = .05, Mantel-Cox test); and stabilized established primary tumor blood vessels, enhancing tumor perfusion (P = .03 for 4T1 tumor model and 0.05 for E0771 tumor model, by two-sided t tests) and, hence, radiation response (P < .01, analysis of variance; n = 7 mice per group). The effects of AKB-9778 on tumor vessels were mediated in part by endothelial nitric oxide synthase activation.

CONCLUSIONS

Our results demonstrate that pharmacological VE-PTP inhibition can normalize the structure and function of tumor vessels through Tie-2 activation, which delays tumor growth, slows metastatic progression, and enhances response to concomitant cytotoxic treatments.

Differential changes in tissue biomarkers after bevacizumab (BEV) alone in a neoadjuvant study of BEV and chemotherapy in ER+ breast cancer (BC) versus triple-negative breast cancer (TNBC) patients (pts)

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Background: The benefit of the anti-VEGF antibody BEV—despite its confirmed activity with chemotherapy—remains unclear in BC pts. This may reflect that its benefit is limited to an unknown subset of BC pts. Methods: We previously reported the outcome and circulating biomarker data of a phase II study of neoadjuvant BEV with chemotherapy in ER+ BC and TNBC pts (NCT00546156; ASCO 2012 abstr 1026). In the present study we evaluated tissue biomarkers after 1 run-in cycle of BEV treatment alone. Patients then received BEV with standard dose-dense doxorubicin/cyclophosphamide/paclitaxel. We analyzed the changes in tissue biomarkers in ER+ BC versus TNBC pts after BEV alone and their correlation with outcome at surgery. The primary endpoint was pathologic response, measured by the Miller-Payne (MP) score (MP5=pCR). Results: Mean MP score was 3.1 for ER+ BC pts versus 4 for TNBC pts (area under ROC=0.60, P<0.001). This supports the hypothesis that the activity of BEV with chemotherapy may depend on BC subtype. In TNBCs, BEV significantly decreased mean microvascular density (MVD) by 33% (p<0.05). MVD was inversely correlated with the fraction of tissue positive for the hypoxia marker CAIX post-BEV (p<0.01). Moreover, a high pre-treatment MVD correlated with an increase in CAIX+ fraction post-BEV (p<0.05). In addition, a drop in MVD associated with increased CAIX+ fraction post-BEV (p=0.05). Finally, high (>60%) pericyte coverage post-BEV—ie, more mature vessels—was inversely correlated with CAIX+ fraction (p<0.05). MP score was more favorable for TNBC pts with lower CAIX+ fraction at baseline (p=0.058) and post-BEV (p<0.05), and higher MVD at baseline (p<0.05) and post-BEV (p<0.05). In contrast, BEV reduced MVD non-significantly by 15% in ER+ BC (p=0.25). There was no correlation between MVD and CAIX+ fraction in ER+ BCs. In contradistinction to TNBC, in ER+ BCs the fraction of CAIX+ tumor was directly correlated with MP score (p<0.01). Conclusions: Our exploratory study suggests that vascular pruning post-BEV may reduce vascular function and increase hypoxia, and reduce the effectiveness of chemotherapy in TNBC. Clinical trial information: NCT00546156.

Coevolution of solid stress and interstitial fluid pressure in tumors during progression: implications for vascular collapse

The stress harbored by the solid phase of tumors is known as solid stress. Solid stress can be either applied externally by the surrounding normal tissue or induced by the tumor itself due to its growth. Fluid pressure is the isotropic stress exerted by the fluid phase. We recently showed that growth-induced solid stress is on the order of 1.3 to 13.0 kPa (10-100 mmHg)--high enough to cause compression of fragile blood vessels, resulting in poor perfusion and hypoxia. However, the evolution of growth-induced stress with tumor progression and its effect on cancer cell proliferation in vivo is not understood. To this end, we developed a mathematical model for tumor growth that takes into account all three types of stresses: growth-induced stress, externally applied stress, and fluid pressure. First, we conducted in vivo experiments and found that growth-induced stress is related to tumor volume through a biexponential relationship. Then, we incorporated this information into our mathematical model and showed that due to the evolution of growth-induced stress, total solid stress levels are higher in the tumor interior and lower in the periphery. Elevated compressive solid stress in the interior of the tumor is sufficient to cause the collapse of blood vessels and results in a lower growth rate of cancer cells compared with the periphery, independently from that caused by the lack of nutrients due to vessel collapse. Furthermore, solid stress in the periphery of the tumor causes blood vessels in the surrounding normal tissue to deform to elliptical shapes. We present histologic sections of human cancers that show such vessel deformations. Finally, we found that fluid pressure increases with tumor growth due to increased vascular permeability and lymphatic impairment, and is governed by the microvascular pressure. Crucially, fluid pressure does not cause vessel compression of tumor vessels.

Targeting placental growth factor/neuropilin 1 pathway inhibits growth and spread of medulloblastoma

Medulloblastoma is the most common pediatric malignant brain tumor. Although current therapies improve survival, these regimens are highly toxic and are associated with significant morbidity. Here, we report that placental growth factor (PlGF) is expressed in the majority of medulloblastomas, independent of their subtype. Moreover, high expression of PlGF receptor neuropilin 1 (Nrp1) correlates with poor overall survival in patients. We demonstrate that PlGF and Nrp1 are required for the growth and spread of medulloblastoma: PlGF/Nrp1 blockade results in direct antitumor effects in vivo, resulting in medulloblastoma regression, decreased metastasis, and increased mouse survival. We reveal that PlGF is produced in the cerebellar stroma via tumor-derived Sonic hedgehog (Shh) and show that PlGF acts through Nrp1-and not vascular endothelial growth factor receptor 1-to promote tumor cell survival. This critical tumor-stroma interaction-mediated by Shh, PlGF, and Nrp1 across medulloblastoma subtypes-supports the development of therapies targeting PlGF/Nrp1 pathway.

Abstract LB-348: Evolution of physical forces in the tumor microenvironment and implications for therapeutic resistance

In solid tumors a fraction of vessels are compressed or totally collapsed (1). As a consequence, the vascular network in tumors is poorly perfused and insufficient for delivery of oxygen and drugs from the blood. This creates a hypoxic microenvironment and reduces delivery of therapeutics, resulting in resistance to radio-, chemo- and immunotherapy. We hypothesized that physical forces in tumors compress tumor vessels. These forces stem from fluid and solid components of tumors. Interstitial fluid pressure (IFP), the isotropic stress exerted by fluid, increases in tumors because of leaky blood vessels and dysfunctional lymphatic vessels. In previous research, we showed that IFP is uniformly elevated in tumors and drops precipitously in the tumor margin. Moreover, elevated IFP cannot compress leaky vessels and thus, vessel compression must result from forces exerted by the solid components of a tumor (2). Despite important in vitro work on solid stress in avascular tumor spheroids, little work has been performed in vivo for the evolution of solid forces in a growing tumor.

To this end, we combined in vivo experiments in mice bearing tumors with a novel mathematical model to analyze the evolution of fluid and solid forces in tumors (3). First, we performed experiments and found that the evolution of solid stress is related to tumor volume. Then, we incorporated this information into our mathematical model and showed that solid stress levels are higher in the tumor interior and lower in the periphery. Elevated compressive stress in the interior of the tumor was found to be sufficient to cause the collapse of blood vessels and result in a lower growth rate of cancer cells compared to the tumor periphery, independently from that caused by the lack of nutrients due to vessel collapse. Furthermore, solid stress levels in the periphery of the tumor can cause blood vessels in the surrounding normal tissue to deform to elliptical shapes but not collapse. We present histological sections of human carcinomas, liposarcomas and pancreatic neuroendocrine tumors that demonstrate such vessel deformations. Contrary to solid stress that is accumulated during progression, model predictions confirmed that IFP levels depend only on the microvascular pressure and the permeability of the tumor vessels.

1. Padera TP, et al. Nature 2004;427(6976):695. 2. Boucher Y, Jain RK. Cancer Res 1992;52(18):5110-4. 3. Stylianopoulos T, Martin JD, Chauhan VP, et al. PNAS 2012;109 (38):15101-8.

Citation Format: Triantafyllos Stylianopoulos, John D. Martin, Saloni Jain, Matija Snuderl, Vikash P. Chauhan, Lance L. Munn, Yves Boucher, Rakesh K. Jain. Evolution of physical forces in the tumor microenvironment and implications for therapeutic resistance. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-348. doi:10.1158/1538-7445.AM2013-LB-348

Abstract LB-76: Tissue biomarkers and interstitial fluid pressure in a phase II study of preoperative (preop) bevacizumab (bev) followed by dose-dense doxorubicin (A)/cyclophosphamide (C)/paclitaxel (T) in combination with bev in HER2-negative operable breast cancer (BC)

Purpose: Recent studies evaluating the efficacy of bev in BC have shown conflicting results, particularly in hormone receptor (HR)+ BC. Identification of predictive biomarkers and their relationship to the pharmacodynamic effects of bev would facilitate the identification of BC patients (pts) most likely to benefit from bev. To examine this, we conducted a unique preop phase II trial with a run-in of single agent bev followed by dose-dense AC-T with bev in two cohorts, one with HR+HER2- BC pts, and a smaller triple negative (TN) BC pts.

Methods: Pts with HR+, HER2- or TNBC were eligible. Treatment consisted of a single dose of bev 10 mg/kg, followed two wks later by A 60 mg/m2 and C 600 mg/m2 with bev 10 mg/kg q2 wks x 4, followed by T 175 mg/m2 with bev 10 mg/kg q2 wks x 3, followed by T 175 mg/m2 x1. Core biopsies and interstitial fluid pressure (IFP) were assessed pre- and post- bev alone. Pathologic response was confirmed centrally and Miller-Payne (MP) was assessed.

Results: The study enrolled 84 pts with HR+ and 20 pts with TN BC. Amongst HR+ pts, 79 had surgical tissue centrally reviewed, and 6 (8%) had a pCR. Amongst TN BC pts, 19 pts had tissue centrally reviewed and 9 (47%) had a pCR. Grade was found to predict MP response in both HR+ and TN pts (p=0.001). Tissue biomarkers and IFP were evaluated as predictors of response to bev. Single-agent bev reduced the mean IFP in the overall cohort and HR+ patients by 20 (p=0.020) and 24.5% (p=0.001), respectively. The IFP decreased &gt; 50% in 24/65 pts and did not change in others. Bev reduced the mean vascular density (MVD) by 33.0% (p&lt;0.05) in TN BC pts, but did not affect the vessel area fraction covered by perivascular cells (PCs). Bev did not modify the fraction of tumor tissue positive for the hypoxia marker CAIX. In TN BC pts, pre- and post-bev, the MVD was inversely correlated with the CAIX fraction (p&lt;0.01). In addition, a drop in MVD associated with increased CAIX+ fraction post-BEV (p=0.05). MP score was more favorable for TN BC pts with lower CAIX+ fraction at baseline (p=0.058) and post-BEV (p&lt;0.05), and higher MVD at baseline (p&lt;0.05) and post-BEV (p&lt;0.05). In contrast, in HR+ BC, BEV reduced MVD non-significantly by 15% (p=0.25) and increased the vessel area fraction covered by PCs (p&lt;0.05). There was no significant correlation between MVD and CAIX+ fraction in HR+ BCs. In contrast to TN BC, in HR+ BCs the fraction of CAIX+ tumor was directly correlated with MP score (p&lt;0.01).

Discussion: Collectively, these results indicate that vascular pruning post-BEV may reduce vascular function and increase hypoxia, which is associated with less favorable pathologic response after BEV with chemotherapy in TN BC. In conclusion, our exploratory study suggests that elevated hypoxia and reduced MVD in TN BC reduces the effectiveness of chemotherapy.

Citation Format: Yves Boucher, John D. Martin, Sara M. Tolaney, Giogio Seano, Shom Goel, Marek Ancukiewicz, Steven J. Isakoff, Eric P. Winer, Ian E. Krop, Rakesh K. Jain. Tissue biomarkers and interstitial fluid pressure in a phase II study of preoperative (preop) bevacizumab (bev) followed by dose-dense doxorubicin (A)/cyclophosphamide (C)/paclitaxel (T) in combination with bev in HER2-negative operable breast cancer (BC) [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-76. doi:10.1158/1538-7445.AM2013-LB-76

Spatial charge configuration regulates nanoparticle transport and binding behavior in vivo

Detailed Charge arrangements : A new set of zwitterionic quantum dots were synthesized and used to study the influence of microscopic charge arrangements on the in vivo behavior of nanoparticles. Experiments using cultured cells and live mice demonstrate that the microscopic arrangement of surface charges strongly influence nonspecific binding, clearance behavior, and in vivo transport of nanoparticles.

Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels

Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-β1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors -inexpensive drugs with decades of safe use - could be rapidly repurposed as cancer therapeutics.

Normalization of tumour blood vessels improves the delivery of nanomedicines in a size-dependent manner

The blood vessels of cancerous tumours are leaky and poorly organized. This can increase the interstitial fluid pressure inside tumours and reduce blood supply to them, which impairs drug delivery. Anti-angiogenic therapies--which 'normalize' the abnormal blood vessels in tumours by making them less leaky--have been shown to improve the delivery and effectiveness of chemotherapeutics with low molecular weights, but it remains unclear whether normalizing tumour vessels can improve the delivery of nanomedicines. Here, we show that repairing the abnormal vessels in mammary tumours, by blocking vascular endothelial growth factor receptor-2, improves the delivery of smaller nanoparticles (diameter, 12 nm) while hindering the delivery of larger nanoparticles (diameter, 125 nm). Using a mathematical model, we show that reducing the sizes of pores in the walls of vessels through normalization decreases the interstitial fluid pressure in tumours, thus allowing small nanoparticles to enter them more rapidly. However, increased steric and hydrodynamic hindrances, also associated with smaller pores, make it more difficult for large nanoparticles to enter tumours. Our results further suggest that smaller (∼12 nm) nanomedicines are ideal for cancer therapy due to their superior tumour penetration.

Pneumatosis intestinalis and mesenteric venous gas - a manifestation of bacterascites in a patient with cirrhosis

We herein report a patient with decompensated cirrhosis secondary to autoimmune hepatitis, who presented with pneumatosis intestinalis (PI) and portal venous gas. Mesenteric ischemia has been recognized as a common and life-threatening cause of PI which portends a grave prognosis. The patient was found to have bacterascites and recovered after appropriate antibiotic therapy. Spontaneous bacterial peritonitis/bacterascites with gas-forming organisms manifesting as PI has not been previously reported.

C-terminal region of USP7/HAUSP is critical for deubiquitination activity and contains a second mdm2/p53 binding site

USP7, also known as the hepes simplex virus associated ubiquitin-specific protease (HAUSP), deubiquitinates both mdm2 and p53, and plays an important role in regulating the level and activity of p53. Here, we report that deletion of the TRAF-like domain at the N-terminus of USP7, previously reported to contain the mdm2/p53 binding site, has no effect on USP7 mediated deubiquitination of Ub(n)-mdm2 and Ub(n)-p53. Amino acids 208-1102 were identified to be the minimal length of USP7 that retains proteolytic activity, similar to full length enzyme, towards not only a truncated model substrate Ub-AFC, but also Ub(n)-mdm2, Ub(n)-p53. In contrast, the catalytic domain of USP7 (amino acids 208-560) has 50-700 fold less proteolytic activity towards different substrates. Moreover, inhibition of the catalytic domain of USP7 by Ubal is also different from the full length or TRAF-like domain deleted proteins. Using glutathione pull-down methods, we demonstrate that the C-terminal domain of USP7 contains additional binding sites, a.a. 801-1050 and a.a. 880-1050 for mdm2 and p53, respectively. The additional USP7 binding site on mdm2 is mapped to be the C-terminal RING finger domain (a.a. 425-491). We propose that the C-terminal domain of USP7 is responsible for maintaining the active conformation for catalysis and inhibitor binding, and contains the prime side of the proteolytic active site.