Sweet dreams: glycosylation controls tumor cell dormancy.

In a recent study in Cancer Cell, Sreekumar et al. used therapy-associated breast cancer mouse models as well as in vitro dormancy models to identify extracellular matrix (ECM)-related tumor cell-autonomous mechanisms of dormancy in residual tumor cells (RTCs). The study reveals an important role of the glycosylation of proteoglycans in sustaining dormancy and opens the door to leverage this biology to eliminate RTCs and prevent recurrence.

DMT1-dependent endosome-mitochondria interactions regulate mitochondrial iron translocation and metastatic outgrowth.

Transient early endosome (EE)-mitochondria interactions can mediate mitochondrial iron translocation, but the associated mechanisms are still elusive. We showed that Divalent Metal Transporter 1 (DMT1) sustains mitochondrial iron translocation via EE-mitochondria interactions in triple-negative MDA-MB-231, but not in luminal A T47D breast cancer cells. DMT1 silencing increases labile iron pool (LIP) levels and activates PINK1/Parkin-dependent mitophagy in MDA-MB-231 cells. Mitochondrial bioenergetics and the iron-associated protein profile were altered by DMT1 silencing and rescued by DMT1 re-expression. Transcriptomic profiles upon DMT1 silencing are strikingly different between 2D and 3D culture conditions, suggesting that the environment context is crucial for the DMT1 knockout phenotype observed in MDA-MB-231 cells. Lastly, in vivo lung metastasis assay revealed that DMT1 silencing promoted the outgrowth of lung metastatic nodules in both human and murine models of triple-negative breast cancer cells. These findings reveal a DMT1-dependent pathway connecting EE-mitochondria interactions to mitochondrial iron translocation and metastatic fitness of breast cancer cells.

The Role of Surgeon-Performed Office and Preincision Ultrasounds in Localization of Parathyroid Adenomas in Primary Hyperparathyroidism.

OBJECTIVE: We studied the use of surgeon-performed office ultrasound (OU) and preincision ultrasound (PIU) in preoperatively localizing parathyroid adenomas in primary hyperparathyroidism (PHPT). METHODS: A retrospective chart review was performed for patients with PHPT who underwent parathyroidectomy between 2013 and 2015. The results of OU and PIU were recorded and compared with the final surgical pathology. RESULTS: Of 348 patients with PHPT, 285 (81.9%) had single-lesion disease, 49 (14.1%) had double-lesion disease, and 14 (4.0%) had multigland disease with 3 or more lesions. For single-lesion disease, the overall sensitivity and specificity of OU to correctly lateralize the lesion were 64.2% and 91.2%, while those of PIU were 89.4% and 93.6%, respectively. The sensitivity and specificity of PIU were comparable to those of 4-dimensional computed tomography (87.1% and 90.7%, respectively) and 99mTc-sestamibi scintigraphy (70.4% and 95.9%, respectively). While the majority of PIU cases were preceded by other imaging studies, the accuracy in localizing lesions was not largely affected by the presence of prior computed tomography and/or 99mTc-sestamibi scintigraphy, as opposed to ultrasounds only. For detecting the presence of multigland disease, the sensitivity and specificity of OU were 26% and 92.2%, while those of PIU were 64.3% and 94.7%, respectively. CONCLUSION: Surgeon-performed OU and PIU are valuable tools in preoperatively localizing the parathyroid adenoma in single-lesion disease, while their utility may be limited for double-lesion or multigland disease. PIU in particular yields high accuracy in detecting parathyroid lesions in combination with other imaging modalities.

Transcriptomic characterization of cancer-testis antigens identifies MAGEA3 as a driver of tumor progression in hepatocellular carcinoma.

Cancer testis antigens (CTAs) are an extensive gene family with a unique expression pattern restricted to germ cells, but aberrantly reactivated in cancer tissues. Studies indicate that the expression (or re-expression) of CTAs within the MAGE-A family is common in hepatocellular carcinoma (HCC). However, no systematic characterization has yet been reported. The aim of this study is to perform a comprehensive profile of CTA de-regulation in HCC and experimentally evaluate the role of MAGEA3 as a driver of HCC progression. The transcriptomic analysis of 44 multi-regionally sampled HCCs from 12 patients identified high intra-tumor heterogeneity of CTAs. In addition, a subset of CTAs was significantly overexpressed in histologically poorly differentiated regions. Further analysis of CTAs in larger patient cohorts revealed high CTA expression related to worse overall survival and several other markers of poor prognosis. Functional analysis of MAGEA3 was performed in human HCC cell lines by gene silencing and in a genetic mouse model by overexpression of MAGEA3 in the liver. Knockdown of MAGEA3 decreased cell proliferation, colony formation and increased apoptosis. MAGEA3 overexpression was associated with more aggressive tumors in vivo. In conclusion MAGEA3 enhances tumor progression and should be considered as a novel therapeutic target in HCC.

Cooperation Between Distinct Cancer Driver Genes Underlies Intertumor Heterogeneity in Hepatocellular Carcinoma.

BACKGROUND AND AIMS: The pattern of genetic alterations in cancer driver genes in patients with hepatocellular carcinoma (HCC) is highly diverse, which partially explains the low efficacy of available therapies. In spite of this, the existing mouse models only recapitulate a small portion of HCC inter-tumor heterogeneity, limiting the understanding of the disease and the nomination of personalized therapies. Here, we aimed at establishing a novel collection of HCC mouse models that captured human HCC diversity. METHODS: By performing hydrodynamic tail-vein injections, we tested the impact of altering a well-established HCC oncogene (either MYC or ß-catenin) in combination with an additional alteration in one of eleven other genes frequently mutated in HCC. Of the 23 unique pairs of genetic alterations that we interrogated, 9 were able to induce HCC. The established HCC mouse models were characterized at histopathological, immune, and transcriptomic level to identify the unique features of each model. Murine HCC cell lines were generated from each tumor model, characterized transcriptionally, and used to identify specific therapies that were validated in vivo. RESULTS: Cooperation between pairs of driver genes produced HCCs with diverse histopathology, immune microenvironments, transcriptomes, and drug responses. Interestingly, MYC expression levels strongly influenced ß-catenin activity, indicating that inter-tumor heterogeneity emerges not only from specific combinations of genetic alterations but also from the acquisition of expression-dependent phenotypes. CONCLUSIONS: This novel collection of murine HCC models and corresponding cell lines establishes the role of driver genes in diverse contexts and enables mechanistic and translational studies.

Mouse Models of Oncoimmunology in Hepatocellular Carcinoma.

Liver cancer is the fourth leading cause of cancer-related mortality worldwide and incidence is on the rise. Hepatocellular carcinoma (HCC) is the most common form of liver cancer, with a complex etiology and limited treatment options. The standard-of-care treatment for patients with advanced HCC is sorafenib, a tyrosine kinase inhibitor that offers limited survival benefit. In the past years, therapeutic options for the treatment of advanced HCC have increased substantially, including additional multikinase inhibitors as well as immune checkpoint inhibitors. Nivolumab and pembrolizumab were approved in 2017 and 2018, respectively, as second-line treatment in advanced HCC. These drugs, both targeting the programmed death-1 pathway, demonstrate unprecedented results, with objective response rates of approximately 20%. However, the majority of patients do not respond, necessitating the identification of biomarkers of response and resistance to immunotherapy. With the recent success of immunotherapies in oncology, mouse models that better recapitulate the human disease and antitumor immune response are needed. This review lists ongoing clinical trials testing immunotherapy in HCC, briefly discusses the unique immunosuppressive environment of the liver, and then delves into the most applicable current murine model systems to study oncoimmunology within the context of HCC, including syngeneic, genetically engineered, and humanized models.

Novel patient-derived preclinical models of liver cancer.

Preclinical models of cancer based on the use of human cancer cell lines and mouse models have enabled discoveries that have been successfully translated into patients. And yet the majority of clinical trials fail, emphasising the urgent need to improve preclinical research to better interrogate the potential efficacy of each therapy and the patient population most likely to benefit. This is particularly important for liver malignancies, which lack highly efficient treatments and account for hundreds of thousands of deaths around the globe. Given the intricate network of genetic and environmental factors that contribute to liver cancer development and progression, the identification of new druggable targets will mainly depend on establishing preclinical models that mirror the complexity of features observed in patients. The development of new 3D cell culture systems, originating from cells/tissues isolated from patients, might create new opportunities for the generation of more specific and personalised therapies. However, these systems are unable to recapitulate the tumour microenvironment and interactions with the immune system, both proven to be critical influences on therapeutic outcomes. Patient-derived xenografts, in particular with humanised mouse models, more faithfully mimic the physiology of human liver cancer but are costly and time-consuming, which can be prohibitive for personalising therapies in the setting of an aggressive malignancy. In this review, we discuss the latest advances in the development of more accurate preclinical models to better understand liver cancer biology and identify paradigm-changing therapies, stressing the importance of a bi-directional communicative flow between clinicians and researchers to establish reliable model systems and determine how best to apply them to expanding our current knowledge.

ß-Catenin Activation Promotes Immune Escape and Resistance to Anti-PD-1 Therapy in Hepatocellular Carcinoma.

PD-1 immune checkpoint inhibitors have produced encouraging results in patients with hepatocellular carcinoma (HCC). However, what determines resistance to anti-PD-1 therapies is unclear. We created a novel genetically engineered mouse model of HCC that enables interrogation of how different genetic alterations affect immune surveillance and response to immunotherapies. Expression of exogenous antigens in MYC;Trp53 -/- HCCs led to T cell-mediated immune surveillance, which was accompanied by decreased tumor formation and increased survival. Some antigen-expressing MYC;Trp53 -/- HCCs escaped the immune system by upregulating the ß-catenin (CTNNB1) pathway. Accordingly, expression of exogenous antigens in MYC;CTNNB1 HCCs had no effect, demonstrating that ß-catenin promoted immune escape, which involved defective recruitment of dendritic cells and consequently impaired T-cell activity. Expression of chemokine CCL5 in antigen-expressing MYC;CTNNB1 HCCs restored immune surveillance. Finally, ß-catenin-driven tumors were resistant to anti-PD-1. In summary, ß-catenin activation promotes immune escape and resistance to anti-PD-1 and could represent a novel biomarker for HCC patient exclusion. SIGNIFICANCE: Determinants of response to anti-PD-1 immunotherapies in HCC are poorly understood. Using a novel mouse model of HCC, we show that ß-catenin activation promotes immune evasion and resistance to anti-PD-1 therapy and could potentially represent a novel biomarker for HCC patient exclusion.See related commentary by Berraondo et al., p. 1003.This article is highlighted in the In This Issue feature, p. 983.

Alterations in synaptic density and myelination in response to exposure to high-energy charged particles.

High-energy charged particles are considered particularly hazardous components of the space radiation environment. Such particles include fully ionized energetic nuclei of helium, silicon, and oxygen, among others. Exposure to charged particles causes reactive oxygen species production, which has been shown to result in neuronal dysfunction and myelin degeneration. Here we demonstrate that mice exposed to high-energy charged particles exhibited alterations in dendritic spine density in the hippocampus, with a significant decrease of thin spines in mice exposed to helium, oxygen, and silicon, compared to sham-irradiated controls. Electron microscopy confirmed these findings and revealed a significant decrease in overall synapse density and in nonperforated synapse density, with helium and silicon exhibiting more detrimental effects than oxygen. Degeneration of myelin was also evident in exposed mice with significant changes in the percentage of myelinated axons and g-ratios. Our data demonstrate that exposure to all types of high-energy charged particles have a detrimental effect, with helium and silicon having more synaptotoxic effects than oxygen. These results have important implications for the integrity of the central nervous system and the cognitive health of astronauts after prolonged periods of space exploration.

Laparoscopic Total Extraperitoneal Hernia Repair Outcomes.

BACKGROUND AND OBJECTIVES: Laparoscopic inguinal hernia repair has become increasingly popular as an alternative to open surgery. The purpose of this study was to evaluate the safety and effectiveness of the laparoscopic total extraperitoneal procedure with the use of staple fixation and polypropylene mesh. METHODS: A retrospective chart review examined outcomes of 1240 laparoscopic hernia operations in 783 patients, focusing on intraoperative and early postoperative complications, pain, and time until return to work and normal physical activities. RESULTS: There were no intraoperative complications in this series; 106 patients experienced early postoperative complications across 8 evaluated categories: urinary retention (4.1%), seroma (3.0%), testicular/hemiscrotal swelling (1.9%), testicular atrophy (0%), hydrocele (0.6%), mesh infection (0.1%), and neurological symptoms (transient, 1.0%; persistent, 0.2%). Patients used an average of 5.6 Percocet pills after the procedure, and mean times until return to work and normal activities, including their routine exercise regimen, were 3.0 and 3.8 days, respectively. CONCLUSION: Complication rates and convalescence times were considered equivalent or superior to those found in other studies assessing both laparoscopic and open techniques. The usage of multiple Endostaples did not result in increased neurologic complications in the early postoperative period when compared with findings in the literature. In the hands of an experienced surgeon, total extraperitoneal repair is a safe, effective alternative to open inguinal hernia repair.

The use of self-gripping (Progrip™) mesh during laparoscopic total extraperitoneal (TEP) inguinal hernia repair: a prospective feasibility and long-term outcomes study.

BACKGROUND: The use of self-gripping mesh during laparoscopic TEP inguinal hernia repairs may eliminate the need for any additional fixation, and thus reduce post-operative pain without the added concern for mesh migration. Long-term outcomes are not yet prospectively studied in a controlled fashion. METHODS: Under IRB approval, from January 2011-April 2013, 91 hernias were repaired laparoscopically with self-gripping mesh without additional fixation. Patients were followed for at least 1 year. Demographics and intraoperative data (defect location, size, and mesh deployment time) are recorded. VAS is used in the recovery room (RR) to score pain, and the Carolinas Comfort Scale ™ (CCS), a validated 0-5 pain/quality of life (QoL) score where a mean score of >1.0 means symptomatic pain, is employed at 2 weeks and at 1 year. Morbidities, narcotic usage, days to full activity and return to work, and CCS scores are reported. RESULTS: Sixty two patients, with 91 hernias repaired with self-gripping mesh, completed follow-up at a mean time period of 14.8 months. Seventeen hernias were direct defects (average size 3.0 cm). Mesh deployment time was 193.7 s. RR pain was 1.1/10 using a VAS. Total average oxycodone/acetaminophen (5 mg/325 mg) usage = 5.0 tablets, days to full activity was 1.6, and return to work was 4.2 days. Thirteen small asymptomatic seromas were palpated without any recurrences or groin tenderness, and all seromas resolved by the 6 month visit. Transient testis discomfort was reported in five patients. Urinary retention was 3.2%. Mean CCS™ scores at the first visit for groin pain laying, bending, sitting, walking, and step-climbing were 0.2, 0.5, 0.4, 0.3, and 0.3, respectively. At the first post op visit, 4.8% had symptomatic pain (CCS > 1). At 14.8 months, no patients reported symptomatic pain with CCS scores for all 62 patients averaging 0.02, (range 0-0.43). There are no recurrences thus far. CONCLUSIONS: Self-gripping mesh can be safely used during laparoscopic TEP inguinal hernia repairs; our cohort had a rapid recovery, and at the 1-year follow-up visit, there were no recurrences and no patients reported any chronic pain as defined by a CCS™ > 1.

Start out: building healthcare careers for minority teenagers.

BACKGROUND: The healthcare industry is currently experiencing a severe shortage of nurses and other allied healthcare professionals. To compound this crisis, the current workforce does not mirror the growing linguistic and cultural diversity of the population needing health care. This article describes a community partnership approach to creating educational and career opportunities in nursing and other health sciences for young, multicultural, bilingual teenagers. METHOD: Several community organizations joined together to design and implement an 8-week summer program entitled "Start Out," which served to integrate life planning, mentorship, nursing assistant training, and college application assistance while providing summer salary stipends and work scholarship opportunities. Twenty-seven students participated in the program. RESULTS: Twenty-four bilingual, economically disadvantaged teenagers 16 to 19 years old, from the greater Seattle metropolitan area, completed the first session of this innovative program and passed the certified nursing assistant examination. CONCLUSION: Culturally focused assistance programs may provide an avenue to meet the current nursing shortage and provide healthcare workers who can be sensitive to the cultural and linguistic needs of the growing ethnic population.