The RNA-binding motif protein 14 regulates telomere integrity at the interface of TERRA and telomeric R-loops

Telomeric repeat-containing RNA (TERRA) and its formation of RNA:DNA hybrids (or TERRA R-loops), influence telomere maintenance, particularly in human cancer cells that use homologous recombination-mediated alternative lengthening of telomeres. Here, we report that the RNA-binding motif protein 14 (RBM14) is associated with telomeres in human cancer cells. RBM14 negatively regulates TERRA expression. It also binds to TERRA and inhibits it from forming TERRA R-loops at telomeres. RBM14 depletion has several effects, including elevated TERRA levels, telomeric R-loops, telomere dysfunction-induced DNA damage foci formation, particularly in the presence of DNA replication stress, pRPA32 accumulation at telomeres and telomere signal-free ends. Thus, RBM14 protects telomere integrity via modulating TERRA levels and its R-loop formation at telomeres.

Unlocking the potential of ultra-high dose fractionated radiation for effective treatment of glioblastoma

Background

Conventional radiation therapy for glioblastoma (GBM) has limited efficacy. Regenerative medicine brings hope for repairing damaged tissue, opening opportunities for elevating the maximum acceptable radiation dose. In this study, we explored the effect of ultra-high dose fractionated radiation on brain injury and tumor responses in immunocompetent mice. We also evaluated the role of the HIF-1α under radiation.

Methods

Naïve and hypoxia-inducible factor-1 alpha (HIF-1α)+/- heterozygous mice received a fractionated daily dose of 20 Gy for three or five consecutive days. Magnetic resonance imaging (MRI) and histology were performed to assess brain injury post-radiation. The 2×105 human GBM1 luciferase-expressing cells were transplanted with tolerance induction protocol. Fractionated radiotherapy was performed during the exponential phase of tumor growth. BLI, MRI, and immunohistochemistry staining were performed to evaluate tumor growth dynamics and radiotherapy responses. Additionally, animal lifespan was recorded.

Results

Fractionated radiation of 5×20 Gy induced severe brain damage, starting 3 weeks after radiation. All animals from this group died within 12 weeks. In contrast, later onset and less severe brain injury were observed starting 12 weeks after radiation of 3×20 Gy. It resulted in complete GBM eradication and survival of all treated animals. Furthermore, HIF-1α+/- mice exhibited more obvious vascular damage 63 weeks after fractionated radiation of 3×20 Gy.

Conclusion

Ultra-high dose fractionated 3×20 Gy radiation can eradicate the GBM cells at the cost of only mild brain injury. The HIF-1α gene is a promising target for ameliorating vascular impairment post-radiation, encouraging the implementation of neurorestorative strategies.

Vancouver call for action to strengthen expertise in radiological protection worldwide

Ionising radiation has been used for over a century for peaceful purposes, revolutionising health care and promoting well-being through its application in industry, science, and medicine. For almost as long, the International Commission on Radiological Protection (ICRP) has promoted understanding of health and environmental risks of ionising radiation and developed a protection system that enables the safe use of ionising radiation in justified and beneficial practices, providing protection from all sources of radiation. However, we are concerned that a shortage of investment in training, education, research, and infrastructure seen in many sectors and countries may compromise society's ability to properly manage radiation risks, leading to unjustified exposure to or unwarranted fear of radiation, impacting the physical, mental, and social well-being of our peoples. This could unduly limit the potential for research and development in new radiation technologies (healthcare, energy, and the environment) for beneficial purposes. ICRP therefore calls for action to strengthen expertise in radiological protection worldwide through: (1) National governments and funding agencies strengthening resources for radiological protection research allocated by governments and international organisations, (2) National research laboratories and other institutions launching and sustaining long-term research programmes, (3) Universities developing undergraduate and graduate university programmes and making students aware of job opportunities in radiation-related fields, (4) Using plain language when interacting with the public and decision makers about radiological protection, and (5) Fostering general awareness of proper uses of radiation and radiological protection through education and training of information multipliers. The draft call was discussed with international organisations in formal relations with ICRP in October 2022 at the European Radiation Protection Week in Estoril, Portugal, and the final call announced at the 6th International Symposium on the System of Radiological Protection of ICRP in November 2022 in Vancouver, Canada.

Survival and renal outcomes of direct heart transplant from veno-arterial extracorporeal membrane oxygenation support

Backgrounds

Patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support are given the highest priority for cardiac transplantation (OHT) in the new UNOS heart allocation policy adopted in October 2018. Although patients may receive an organ quicker there may not be enough time to recover end-organ function. To date, little is known about survival and renal outcomes of direct OHT in patients that have been supported with VA-ECMO as a bridge to transplant due to limited experience in most transplant centers.

Purpose

The aim of this study was to investigate survival and renal outcomes of direct OHT in patients supported with VA-ECMO prior to transplant.

Methods

From January 2010 to February 2022, 23 patients who received single organ OHT alone directly from VA-ECMO support were retrospectively analyzed (16 patients after the new allocation policy). Kaplan-Meier analysis was used to estimate event-free survival.

Results

The median age of recipients was 48 years. The median length of pre-transplant VA-ECMO support was 5 days. Additional pre-transplant support with intra-aortic balloon pump or Impella was utilized in 15 patients (65.2%) and 2 patients (9%) respectively. There was a trend toward improvement of serum creatinine after initiation of VA-ECMO support (Pre-ECMO: 1.66±1.22 mg/dl vs. Pre-OHT: 1.20±0.74 mg/dl, P=0.084). Four patients required preoperative renal replacement therapy (RRT); three were on RRT at the time of OHT. The median ischemic time of donor hearts was 168 minutes. VA-ECMO support was continued in 10 patients (43.5%) after OHT.

Hospital mortality was 8.7% (2 patients). Post-transplant RRT was required in 9 patients (39.1%), and, of these, 5 patients were transitioned to permanent dialysis. Among the 14 patients who did not require post-transplant RRT, none required RRT during the follow-up period (median, 21.5 months). Kaplan-Meier survival analysis showed that estimated survival at 1 year and 3 years were 86.1%, and 77.5%, respectively (Figure 1A). The freedom from dialysis rate was 82.4% at 1 year, and 74.9% at 3 years (Figure 2A). Both survival (100% vs. 66.7%, P=0.008, Fig.1B) and dialysis free rate (100% vs. 55.6%, P=0.002, Figure 2B) at one-year were significantly worse in patients who required postoperative RRT.

Conclusions

To our knowledge this is the largest single center study of OHT in patients that were supported with VA-ECMO. VA-ECMO as a bridge to end-organ recovery and OHT resulted in excellent outcomes. Patients who required post-transplant RRT more likely to require long-term dialysis, while those that did not receive RRT showed favorable outcomes. Overall survival in this patient population is comparable to patients that were not on VA-ECMO prior to transplant.

Funding Acknowledgement

Type of funding sources: None.

Summary of the 2021 ICRP workshop on the future of radiological protection

The International Commission on Radiological Protection (ICRP) has embarked on a process to review and revise the current System of Radiological Protection ('the System'). To stimulate discussion, the ICRP published two open-access articles: one on aspects of the System that might require review, and another on research that might improve the scientific foundation of the System. Building on these articles, the ICRP organized a Workshop on the Future of Radiological Protection as an opportunity to engage in the review and revision of the System. This digital workshop took place from 14 October-3 November 2021 and included 20 live-streamed and 43 on-demand presentations. Approximately 1500 individuals from 100 countries participated. Based on the subjects covered by the presentations, this summary is organized into four broad areas: the scientific basis, concepts and application of the System; and the role of the ICRP. Some of the key topics that emerged included the following: classification of radiation-induced effects; adverse outcome pathway methodologies; better understanding of the dose-response relationship; holistic and reasonable approaches to optimization of protection; radiological protection of the environment; ethical basis of the System; clarity, consistency and communication of the System; application of the System in medicine and application of the principles of justification and optimization of protection.

Keeping the ICRP recommendations fit for purpose

The International Commission on Radiological Protection (ICRP) has embarked on a review and revision of the system of Radiological Protection that will update the 2007 general recommendations in ICRPPublication 103. This is the beginning of a process that will take several years, involving open and transparent engagement with organisations and individuals around the world. While the system is robust and has performed well, it must adapt to address changes in science and society to remain fit for purpose. The aim of this paper is to encourage discussions on which areas of the system might gain the greatest benefit from review, and to initiate collaborative efforts. Increased clarity and consistency are high priorities. The better the system is understood, the more effectively it can be applied, resulting in improved protection and increased harmonisation. Many areas are identified for potential review including: classification of effects, with particular focus on tissue reactions; reformulation of detriment, potentially including non-cancer diseases; re-evaluation of the relationship between detriment and effective dose, and the possibility of defining detriments for males and females of different ages; individual variation in the response to radiation exposure; heritable effects; and effects and risks in non-human biota and ecosystems. Some of the basic concepts are also being considered, including the framework for bringing together protection of people and the environment, incremental improvements to the fundamental principles of justification and optimisation, a broader approach to protection of individuals, and clarification of the exposure situations introduced in 2007. In addition, ICRP is considering identifying where explicit incorporation of the ethical basis of the system would be beneficial, how to better reflect the importance of communications and stakeholder involvement, and further advice on education and training. ICRP invites responses on these and other areas relating to the review of the System of Radiological Protection.

ICRP recommendations for recovery

In 2020, the International Commission on Radiological Protection (ICRP) issued Publication 146 which provides a framework of the radiological protection of people and the environment in the case of a large nuclear accident. Mitigation of radiological consequences is achieved using the fundamental principles of justification of decisions and optimisation of protection. These recommendations emphasise the importance of the optimisation of protection for the rehabilitation of living and working conditions in the affected areas during the intermediate and long-term phases. They underline the role of co-operation between the authorities, experts, and the affected population in the co-expertise process to facilitate informed decisions about their own protection. ICRP defines reference levels to be selected within generic bands of exposure considering the induced risk of radiation, as well as the feasibility of controlling the situation.

Neuroinflammation After Stereotactic Radiosurgery-Induced Brain Tumor Disintegration Is Linked to Persistent Cognitive Decline in a Mouse Model of Metastatic Disease

PURPOSE

Improved efficacy of anticancer therapy and a growing pool of survivors give rise to a question about their quality of life and return to premorbid status. Radiation is effective in brain metastasis eradication, although the optimal approach and long-term effects on brain function are largely unknown. We studied the effects of radiosurgery on brain function.

METHODS AND MATERIALS

Adult C57BL/6J mice with or without brain metastases (rat 9L gliosarcoma) were treated with cone beam single-arc stereotactic radiosurgery (SRS; 40 Gy). Tumor growth was monitored using bioluminescence, whereas longitudinal magnetic resonance imaging, behavioral studies, and histologic analysis were performed to evaluate brain response to the treatment for up to 18 months.

RESULTS

Stereotactic radiosurgery (SRS) resulted in 9L metastases eradication within 4 weeks with subsequent long-term survival of all treated animals, whereas all nontreated animals succumbed to the brain tumor. Behavioral impairment, as measured with a recognition memory test, was observed earlier in mice subjected to radiosurgery of tumors (6 weeks) in comparison to SRS of healthy brain tissue (10 weeks). Notably, the deficit resolved by 18 weeks only in mice not bearing a tumor, whereas tumor eradication was complicated by the persistent cognitive deficits. In addition, the results of magnetic resonance imaging were unremarkable in both groups, and histopathology revealed changes. SRS-induced tumor eradication triggered long-lasting and exacerbated neuroinflammatory response. No demyelination, neuronal loss, or hemorrhage was detected in any of the groups.

CONCLUSIONS

Tumor disintegration by SRS leads to exacerbated neuroinflammation and persistent cognitive deficits; therefore, methods aiming at reducing inflammation after tumor eradication or other therapeutic methods should be sought.

Computed tomography of the head and the risk of brain tumours during childhood and adolescence: results from a case-control study in Japan

To clarify whether medical radiation exposure, especially from head computed tomography (CT), increases the risk of brain tumours in young patients in Japan, which ranks the second highest in the world in the number of paediatric CT examinations following the US. From 2011 to 2015, we performed a case-control study of 120 brain tumour patients and 360 appendicitis patients as controls. Reasons, the number of brain and head CT scans date were available from interviews. A cumulative radiation dose to the brain was calculated as a sum of doses received from head CT scans and from conventional X-rays and estimated using a reference table derived from a literature review of published studies. We performed conditional logistic regression to assess the risk of brain tumours from brain and head CT, and from conventional head X-ray procedures. The case group received on average 1.8 CTs to the brain area and 2.2 CTs to the whole head, with a mean estimated brain dose of 32 ±13 mGy. The odds ratio for developing a brain tumour from having a brain CT was 0.93 (95% confidence interval: 0.38-1.82). This was hardly altered when adjusting for parental educational history and for other diseases (history of neurological disease and attention-deficit disorder/attention-deficit hyperactivity disorder). Neither whole head CT nor cumulative brain dose to the brain increased the risk of glioma or of all brain tumours. Although this study conducted in Japan, where ranks second in the number of CT scans conducted in the world, did not show an increased risk of brain tumours related to CT scans, it should be taken with caution due to a case-control study with limited sample size.

Modeling human pediatric and adult gliomas in immunocompetent mice through costimulatory blockade

Currently, human glioma tumors are mostly modeled in immunodeficient recipients; however, lack of interactions with adaptive immune system is a serious flaw, particularly in the era when immunotherapies dominate treatment strategies. Our group was the first to successfully establish the orthotopic transplantation of human glioblastoma (GBM) in immunocompetent mice by inducing immunological tolerance using a short-term, systemic costimulation blockade strategy (CTLA-4-Ig and MR1). In this study, we further validated the feasibility of this method by modeling pediatric diffuse intrinsic pontine glioma (DIPG) and two types of adult GBM (GBM1, GBM551), in mice with intact immune systems and immunodeficient mice. We found that all three glioma models were successfully established, with distinct difference in tumor growth patterns and morphologies, after orthotopic xenotransplantation in tolerance-induced immunocompetent mice. Long-lasting tolerance that is maintained for up to nearly 200 d in GBM551 confirmed the robustness of this model. Moreover, we found that tumors in immunocompetent mice displayed features more similar to the clinical pathophysiology found in glioma patients, characterized by inflammatory infiltration and strong neovascularization, as compared with tumors in immunodeficient mice. In summary, we have validated the robustness of the costimulatory blockade strategy for tumor modeling and successfully established three human glioma models including the pediatric DIPG whose preclinical study is particularly thwarted by the lack of proper animal models.

Abstract P1-06-11: Microsatellite instability in triple negative breast cancers

Background:Microsatellite instability (MSI) is a phenotype resulting from defect in mismatch repair genes. The Food and Drug Administration approved anti-programmed death 1 (PD-1) immune checkpoint inhibitor for any solid tumor with MSI-high (MSI-H). Some tumors had good response to PD-1 blockade and it is a promising treatment for a part of refractory breast cancers. Our goal was to determine the frequency of MSI in triple negative breast cancer (TNBC), one of the most clinically aggressive subtypes.

Patients and Methods:This study included 228 patients with primary TNBC underwent resection without neoadjuvant chemotherapy between January 2004 and December 2014. Genomic DNA was extracted from formalin-fixed and paraffin-embedded tissue. Tumor and control DNA were amplified by polymerase chain reaction at the following 5 microsatellite markers: NR-21, BAT-26, BAT-25, NR-24, MONO-27. We classified the tumors as microsatellite stable(MSS), MSI-low or MSI-H.

Results: The mean age of patients was 59 years (range: 30-89) and all were women. T1 tumors were 57.9% and N0 were 67.5%. Meanwhile, the tumors with nuclear grade 3 were 66.2% and high Ki-67 (> 30%) were 66.7%. Among the 228 tumors, 222 tumors (97.4%) revealed MSS, of which 6 (2.6%) revealed MSI and 2 (0.9%) were MSI-H. Among the MSI tumors, T and N factor were showed as follows: T1: 2 tumors, T2: 3 tumors, T3: 1 tumor, N0: 5 tumors and N1: 1 tumor. Of two MSI-H tumors, one showed T1N0 and another showed T2N0. The both of them showed nuclear grade 3, high Ki-67 (> 30%) and had common following instable markers: NR-21, BAT-26 and BAT-25.

Conclusions: Our results demonstrated that the frequency of MSI-H was 0.9% (2/228). MSI might not be useful as a biomarker for immune check point inhibitors. MSI should be combined with another biomarker such as tumor mutational burden in TNBC.

Citation Format: Kurata K, Kubo M, Mori H, Kawaji H, Motoyama Y, Kuroki L, Yamada M, Kaneshiro K, Kai M, Nakamura M. Microsatellite instability in triple negative breast cancers [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 P1-06-11.

Abstract P4-06-22: Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer

Background: Many analyzes regarding immunotherapies using checkpoint blockade has made it clear that tumor infiltrating lymphocytes (TILs) plays an important role in treating cancers with high levels of somatic mutations such as triple-negative breast cancer (TNBC). We reported the relationship between TILs and PD-L1 expression, and revealed that high-TILs/positive-PD-L1 expression population in TNBC was associated with better prognosis (Oncotarget 2017). However, its molecular mechanism is still unclear. Meanwhile, T-box transcription factor 21 (T-bet) which regulates effecter T-cells activation is derived by stimulation of T-cell receptor and IL-12. Activated T-cells work as antitumor lymphocytes by enhancing the production of cytokines such as INFγ. We focused on T-bet and examined the function of activated T-cells.

Patients and Methods: This study included 242 patients with primary TNBC who underwent resection without neoadjuvant chemotherapy at our three hospitals between January 2004 and December 2014. The immunohistochemistry scoring for CD8 and T-bet expression on TILs was defined as ≥30 per 0.00625mm2. PD-L1 positivity was defined as ≥1% of tumor cells staining positive for PD-L1.

Results: Of the 242 TNBC, CD8 on TILs was expressed as positive in 127 (52.5%) tumors, T-bet on TILs was expressed as positive in 67 (27.7%) tumors, and PD-L1 expression on tumor cells was expressed as positive in 99 (40.9%) tumors. T-bet expression was significantly correlated with CD8 expression (P<0.0001) and PD-L1 expression (P=0.0004). There was no significant difference in recurrence free survival (RFS) and overall survival (OS) regardless of CD8 or PD-L1expression level. Meanwhile, the patients with T-bet-positive tumors had a longer OS, compared to those with T-bet-negative tumors (P = 0.13 in RFS and P = 0.047 in OS). The multivariate analysis revealed that T-bet expression on TILswas an independent and positive prognostic factor for OS(HR = 0.5, 95%CI 0.1-0.9, P = 0.035).

Conclusion: OS was significantly longer among patients with high T-bet expressing TNBC. These results may validate the significance of T-bet as a biomarker for various immunotherapies in TNBC.

Citation Format: Mori H, Kubo M, Kai M, Kurata K, Kawaji H, Kaneshiro K, Motoyama Y, Kuroki R, Yamada M, Nishimura R, Okido M, Oda Y, Nakamura M. Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer [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 P4-06-22.

Antimicrobial resistance in leprosy: results of the first prospective open survey conducted by a WHO surveillance network for the period 2009-15

OBJECTIVES

Antimicrobial resistance (AMR) is a priority for surveillance in bacterial infections. For leprosy, AMR has not been assessed because Mycobacterium leprae does not grow in vitro. We aim to obtain AMR data using molecular detection of resistance genes and to conduct a prospective open survey of resistance to antileprosy drugs in countries where leprosy is endemic through a WHO surveillance network.

METHODS

From 2009 to 2015, multi-bacillary leprosy cases at sentinel sites of 19 countries were studied for resistance to rifampicin, dapsone and ofloxacin by PCR sequencing of the drug-resistance-determining regions of the genes rpoB, folP1 and gyrA.

RESULTS

Among 1932 (1143 relapse and 789 new) cases studied, 154 (8.0%) M. leprae strains were found with mutations conferring resistance showing 182 resistance traits (74 for rifampicin, 87 for dapsone and 21 for ofloxacin). Twenty cases showed rifampicin and dapsone resistance, four showed ofloxacin and dapsone resistance, but no cases were resistant to rifampicin and ofloxacin. Rifampicin resistance was observed among relapse (58/1143, 5.1%) and new (16/789, 2.0%) cases in 12 countries. India, Brazil and Colombia reported more than five rifampicin-resistant cases.

CONCLUSIONS

This is the first study reporting global data on AMR in leprosy. Rifampicin resistance emerged, stressing the need for expansion of surveillance. This is also a call for vigilance on the global use of antimicrobial agents, because ofloxacin resistance probably developed in relation to the general intake of antibiotics for other infections as it is not part of the multidrug combination used to treat leprosy.

Progression-dependent transport heterogeneity of breast cancer liver metastases as a factor in therapeutic resistance

Metastatic disease is a major cause of mortality in cancer patients. While many drug delivery strategies for anticancer therapeutics have been developed in preclinical studies of primary tumors, the drug delivery properties of metastatic tumors have not been sufficiently investigated. Therapeutic efficacy hinges on efficient drug permeation into the tumor microenvironment, which is known to be heterogeneous thus potentially making drug permeation heterogeneous, also. In this study, we have identified that 4 T1 liver metastases, treated with pegylated liposomal doxorubicin, have unfavorable and heterogeneous transport of doxorubicin. Our drug extravasation results differ greatly from analogous studies with 4 T1 tumors growing in the primary site. A probabilistic tumor population model was developed to estimate drug permeation efficiency and drug kinetics of liver metastases by integrating the transport and structural properties of tumors and delivered drugs. The results demonstrate significant heterogeneity in metastases with regard to transport properties of doxorubicin within the same animal model, and even within the same organ. These results also suggest that the degree of heterogeneity depends on the stage of tumor progression and that differences in transport properties can define transport-based tumor phenotypes. These findings may have valuable clinical implications by illustrating that therapeutic agents can permeate and eliminate metastases of "less resistant" transport phenotypes, while sparing tumors with more "resistant" transport properties. We anticipate that these results could challenge the current paradigm of drug delivery into metastases, highlight potential caveats for therapies that may alter tumor perfusion, and deepen our understanding of the emergence of drug transport-based therapeutic resistance.

Errata: Internal doses from radionuclides and their health effects following the Fukushima accident (J. Radiol. Prot. 2018 38 1253-68)

This article presents errata on a published article.

RNA-binding protein RBM14 regulates dissociation and association of non-homologous end joining proteins

Defects in the DNA damage response (DDR) are associated with multiple diseases, including cancers and neurodegenerative disorders. Emerging evidence indicates involvement of RNA-binding proteins (RBPs) in DDR. However, functions of RBPs in the DDR pathway remain elusive. We have shown previously that the RNA-binding protein RBM14 is required for non-homologous end joining (NHEJ). Here we show that RBM14 is required for efficient recruitment of XRCC4 and XLF to chromatin and the release of KU proteins from chromatin upon DNA damage. Failure of this process leads to accumulation of double-strand breaks (DSBs) in cells. Thus RBM14 plays crucial role in regulation of NHEJ upon DNA damage.

Abstract P6-07-05: PD-L1 expression and decreased tumor-infiltrating lymphocytes are associated with poor prognosis in patients with triple negative breast cancer

Background: Tumor microenvironment has been considered to have an active role in determining the aggressiveness of tumor cells. Recently, programmed cell death ligand-1 (PD-L1) expression or tumor-infiltrating lymphocytes (TILs) are known to be an important prognostic factor of breast cancer. However, the correlation of expression of PD-L1 and TILs still remains unclear. Triple-negative breast cancer (TNBC) is a heterogeneous tumor that encompasses many different subclasses. Further identification of these subclasses is necessary in order to predict prognosis and choose appropriate treatments. Our goal was to correlate PD-L1 expression with clinicopathological features including TILs by using a large cohort of TNBCs.

Patients and Methods: This study included 248 patients with primary TNBC who underwent resection without neoadjuvant chemotherapy at our three hospitals between January 2004 and December 2014. The tumor subtypes were routinely determined immunohistochemically by using resected specimens. IHC scoring for PD-L1 expression was defined in reference to that for HER2 expression. PD-L1 positivity was defined as both IHC 2+ and IHC 3+. Cases were defined as high if stromal TILs ≥50% according to recommendations by the International TILs Working Group.

Results: Of the 248 TNBCs, PD-L1 were expressed as positive in 103 (41.5%) tumors, and TILs were highly present in 118 (47.6%) tumors. PD-L1 expression was significantly correlated with higher levels of TILs (P < 0.0001). There was no significant difference when the prognosis of the patients who had PD-L1-positive tumors was compared with that of the patients who had PD-L1-negative tumors (P = 0.56 in recurrence free survival [RFS] and P = 0.13 in overall survival [OS]). Meanwhile, the patients with high-TILs tumors had longer OS, compared to the patients with low-TILs tumors (P = 0.55 in RFS and P = 0.016 in OS). The analysis in the cross effect between PD-L1 expression and TILs using cox proportional hazards model demonstrated that the PD-L1 expression and TILs are not independent factors(P = 0.0018 in RFS and P = 0.015 in OS). The PD-L1-positive group with low-TILs had significantly shorter survival than the PD-L1-positive group with high-TILs (hazard ratio [HR] = 4.7, 95% confidence interval [CI] 1.6–12.7, P = 0.0067 in RFS; HR = 8.4, 95%CI 2.3-30.3, P = 0.0019 in OS).

Conclusions: Our data indicated that PD-L1 expression was related to higher levels of TILs, and PD-L1-positive tumors with low-TILs were associated with poor prognosis in patients with TNBCs. It is proposed that these biomarkers may be of use for predicting their prognosis and essential in the subclassification of TNBCs.

Citation Format: Mori H, Kubo M, Yamaguti R, Nishimura R, Osako T, Arima N, Okumura Y, Okido M, Yamada M, Kai M, Kishimoto J, Oda Y, Nakamura M. PD-L1 expression and decreased tumor-infiltrating lymphocytes are associated with poor prognosis in patients with triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-05.

Roles of RNA-Binding Proteins in DNA Damage Response

Living cells experience DNA damage as a result of replication errors and oxidative metabolism, exposure to environmental agents (e.g., ultraviolet light, ionizing radiation (IR)), and radiation therapies and chemotherapies for cancer treatments. Accumulation of DNA damage can lead to multiple diseases such as neurodegenerative disorders, cancers, immune deficiencies, infertility, and also aging. Cells have evolved elaborate mechanisms to deal with DNA damage. Networks of DNA damage response (DDR) pathways are coordinated to detect and repair DNA damage, regulate cell cycle and transcription, and determine the cell fate. Upstream factors of DNA damage checkpoints and repair, “sensor” proteins, detect DNA damage and send the signals to downstream factors in order to maintain genomic integrity. Unexpectedly, we have discovered that an RNA-processing factor is involved in DNA repair processes. We have identified a gene that contributes to glioblastoma multiforme (GBM)’s treatment resistance and recurrence. This gene, RBM14, is known to function in transcription and RNA splicing. RBM14 is also required for maintaining the stem-like state of GBM spheres, and it controls the DNA-PK-dependent non-homologous end-joining (NHEJ) pathway by interacting with KU80. RBM14 is a RNA-binding protein (RBP) with low complexity domains, called intrinsically disordered proteins (IDPs), and it also physically interacts with PARP1. Furthermore, RBM14 is recruited to DNA double-strand breaks (DSBs) in a poly(ADP-ribose) (PAR)-dependent manner (unpublished data). DNA-dependent PARP1 (poly-(ADP) ribose polymerase 1) makes key contributions in the DNA damage response (DDR) network. RBM14 therefore plays an important role in a PARP-dependent DSB repair process. Most recently, it was shown that the other RBPs with intrinsically disordered domains are recruited to DNA damage sites in a PAR-dependent manner, and that these RBPs form liquid compartments (also known as “liquid-demixing”). Among the PAR-associated IDPs are FUS/TLS (fused in sarcoma/translocated in sarcoma), EWS (Ewing sarcoma), TARF15 (TATA box-binding protein-associated factor 68 kDa) (also called FET proteins), a number of heterogeneous nuclear ribonucleoproteins (hnRNPs), and RBM14. Importantly, various point mutations within the FET genes have been implicated in pathological protein aggregation in neurodegenerative diseases, specifically with amyotrophic lateral sclerosis (ALS), and frontotemporal lobe degeneration (FTLD). The FET proteins also frequently exhibit gene translocation in human cancers, and emerging evidence shows their physical interactions with DDR proteins and thus implies their involvement in the maintenance of genome stability.

Abstract P5-05-04: MALDI mass spectrometry imaging profile of low molecular metabolites in breast carcinoma tissues embedded in frozen tissue microarray

[Background]

Metabolomics is now widely utilized for searching disease markers or identification of new drug targets. In common method, tissue samples originated in human resected specimens are stored by formalin-fixed, paraffin-embedded (FFPE) blocks. However, these samples are inadequate to measure low molecular metabolites or lipids. Furthermore, extraction process that is required for conventional mass-spectrometry causes the loss of information on the spatial localization of the metabolites. In this study, we directly analyzed breast carcinoma tissues embedded in frozen tissue microarray (fTMA) using MALDI mass spectrometry imaging (MALDI-MSI). With our original method, we could obtain profiles of low molecular metabolite and mapping images of several tissues at one time.

[Method]

Six fTMA blocks were constructed by 119 breast tissues (carcinoma 84, normal 35) from 99 patients and sectioned at 10 um thickness. MADLI-MSI were performed by AXIMA Confidence (Shimadzu, Japan) with 9-aminoacridine as a matrix (m/z range:50∼1000, Negative Ion mode). Carcinoma and normal area in individual tissues were confirmed by H&E staining of slide grasses after MADLI-MSI analysis. Acquired MSI data were processed with the freely available software BioMap (Novartis, Switzerland).

[Result]

We could detected 1,915 peaks derive from endogenous metabolite by direct tissue MALDI-MSI analysis of breast carcinoma fTMA. Among them, 185 peaks that could be commonly detected were subjected to further analysis. Among these peaks, we could identify 18 metabolites related to energy metabolism such as ATP. By comparison of metabolite profiles obtained from carcinoma with normal tissues, we found that the energy charge (EC; which is related to ATP, ADP and AMP concentrations) and the sum of adenosine phosphate compound intensities (AXP) were significantly higher than that of normal tissue (EC; T : N = 0.56 : 0.35, AXP; 17453 : 2066, p<0.0001), but there were no significant difference with lymph node metastasis, tumor histological type and tumor size. In comparison with tumor subtype, higher EC was observed in ER(+)/ Her2(-) tumor than others but AXP showed no significant among all subtypes including Ki-67 labeling index.

[Conclusion]

A combination of fTMA and MALDI-MSI is promising approach for biomarker discovery because it can achieve high throughput metabolic mapping without obvious artifact or other problem. In this study, even though high EC value were indicated in carcinoma tissue than normal but newly biomarker candidate was indeterminate at this moment. Identification of the candidates of novel carcinoma tissue biomarker is now underway.

Citation Format: Torata N, Kubo M, Miura D, Ohuchida K, Miyazaki T, Fujimura Y, Hayakawa E, Kai M, Oda Y, Mizumoto K, Hashizume M, Nakamura M. MALDI mass spectrometry imaging profile of low molecular metabolites in breast carcinoma tissues embedded in frozen tissue microarray. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-05-04.

Abstract P3-06-07: Changes in the tumor microenvironment develop acquired resistance to pegylated liposomal doxorubicin in breast cancer mouse model

Pegylated liposomal doxorubicin (PLD) is one of the most widely used nanotherapeutics for the treatment of advanced/metastatic breast cancer. PLD accumulates in tumors utilizing so-called the enhanced permeation and retention (EPR) effect. Nevertheless, therapeutic efficacy and long term survival remain variable due to the development of acquired resistance. Elucidating the mechanisms of acquired resistance to PLD shall help developing new strategies to improve therapeutic outcome. It has been largely overlooked that the transport of therapeutics across biological barriers can significantly affect the efficacy of cancer therapies. Previously, we showed that the transport of PLD to tumors depends both on the tumor type and organ site. This effect is controlled by the extent to which endothelial cells (ECs) are covered by the collagen type IV (Col4) in the basement membrane, which in turn is influenced by the levels of MMP-9. Here, we have developed 4T1 tumor model which develops acquired resistance to PLD and spontaneous lung metastases. Our objective is to elucidate the resistant mechanism by evaluating the changes in the transport of PLD to the sensitive and resistant/metastatic tumors.

BALB/c mice bearing 4T1 cancers were treated with PLD intravenously when tumor volumes reached a size of approximately 100-200 mm3 . Tumor volumes in all mice decreased after initial PLD injections (sensitive). However, tumors started to grow again after 20 days and didn't respond to the second/third injections (resistant). Furthermore, 13 out of 14 mice developed spontaneous lung metastases. To elucidate the mechanisms of the resistance, mice bearing sensitive or resistant tumors were sacrificed after 24 hours of PLD injection, respectively. PLD accumulation in tumors was evaluated by imaging fluorescence of doxorubicin. Immunofluorescence staining was performed to evaluate the expression of ECs, Col4, MMP-9, and efflux pump associated p-glycoprotein (P-gp) in the primary tumors, and the expression of ECs and Col4 were also evaluated in lung metastases.

PLD accumulation was significantly decreased in the resistant tumors compared to the sensitive tumors, although P-gp expression was not increased in the resistant tumors. The amount of ECs and Col4 increased in the resistant tumors. Interestingly, ECs were covered more tightly by Col4 in the resistant tumors as compared with the sensitive tumors, which could decrease the EPR effect in the tumors. MMP-9 expression decreased in the resistant tumors, suggesting less degradation of Col4 in the basement membrane. Coverage of ECs by Col4 was similar between the metastatic lung tumors and uninvolved lung tissue as well as the resistant primary tumors, indicating the EPR effect is not increased in the metastatic tumors.

In summary, ratio of ECs covered by Col4 is higher in the resistant/metastatic tumors as compared to that in the sensitive primary tumors. This structural change in the tumor microenvironment, impeding the sufficient PLD transport to the tumors after the initial PLD therapy, can be a cause of acquired resistance/development of lung metastasis. These changes should be taken into account to develop strategies for overcoming the acquired resistance and metastasis.

Citation Format: Kai M, Liu YT, Saito Y, Ferrari M, Yokoi K. Changes in the tumor microenvironment develop acquired resistance to pegylated liposomal doxorubicin in breast cancer mouse model. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-06-07.

Abstract P4-09-15: BRCAness and PD-L1 expression of basal-like and not basal-like triple negative breast cancer

Background: Triple Negative Breast Cancer (TNBC) subtype occurs in approximately 20% of all patients with breast cancer and is associated with rapid growth, early metastasis and poor prognosis compared with other subtypes. TNBCs are a heterogeneous disease entity and further subclassification is needed, but still ongoing. In this study, we assessed BRCAness, defined as shared characteristics between sporadic and BRCA1-mutated tumors, in a cohort of basal-like and non-basal-like TNBCs.

Patients and Methods: DNA was isolated from formalin-fixed paraffin-embedded tumor tissues and BRCAness status was analyzed in 262 patients with primary TNBCs resected at our three hospitals between 2004 and 2014. Classification of BRCAness was performed by using Multiple Ligation-dependent Probe Amplification (MLPA) with the probemix P376 BRCA1ness by MRC (Amsterdam, Holland). The tumor subtypes were routinely determined immunohistochemically by using resected specimens. Basal-like phenotype was defined as being positive for Epidermal Growth Factor Receptor (EGFR) and/or Cytokeratin 5/6 (CK5/6). Moreover, TNBCs were stained and analyzed for programmed cell death ligand-1 (PD-L1) expression as a target of new immune therapies.

Results: Of 262 TNBCs, 232 tumors (88.5%) was a basal-like phenotype. The results of MLPA assay showed that 159 (68.5%) of 232 tumors had a BRCAness profile. Patients with basal-like BRCAness tumors were younger than patients with basal-like non-BRCAness tumors (p<0.0001). There was no significant difference between the two groups regarding pathological stage. The basal-like BRCAness group had shorter relapse-free survival (RFS) and overall survival (OS) than the basal-like non-BRCAness group (p=0.028 and p=0.13, respectively), and anthracycline-based regimens provided greater benefit to the basal-like BRCAness group significantly (p=0.01 in RFS and p=0.007 in OS). PD-L1 was expressed in 71 (44.7%) of 159 basal-like TNBCs with BRCAness.

Conclusion: We reported the majority of basal-like TNBCs showed a BRCAness profile and PD-L1 expressed in approximately 50% of BRCAness tumors. It is known that about 30% of BRCAness tumors are BRCA1-mutated tumors. Those biomarkers are essential for subclassification of TNBCs and may offer not only platinum-based chemotherapy but also novel therapies, such as immune-targeted therapies of PD-1/PD-L1 inhibitors and PARP inhibitors, to patients with basal-like TNBCs with BRCAness.

Citation Format: Mori H, Kubo M, Yamada M, Kai M, Osako T, Nishimura R, Arima N, Okido M, Kuroki S, Oda Y, Nakamura M. BRCAness and PD-L1 expression of basal-like and not basal-like triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-15.

Abstract P3-03-02: Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice

Background and Purpose: Despite recent progress in our endocrine therapy of hormone receptor positive (HR+) breast cancers, a significant number of patients with primary breast cancer continue to relapse, and those with stage IV disease face a median overall survival of ∼ 3.5 years. Primary or acquired resistance to anti-estrogen-based therapies is an overarching challenge. To guide our treatment selection, there is an essential need to improve our understanding of the biology of HR+ breast tumors responsive to and those resist to anti-estrogens or aromatase inhibitors (AIs). The application of patient-derived xenografts (PDXs) in preclinical studies has begun to open the door to mimicking human disease on the research bench. However, HR+ breast cancer PDXs are difficult to establish. Although preclinical data from DeRose et al [Nat. Med. 2011: 17:1514-1520] indicate that the rate of engraftment serves as an independent predictor for poor outcome, the question which has not yet been adequately addressed is: "why some tumors can grow in mice, and some don't, even when their clinical, pathological stage and subtype (i.e. ER positivity) are same?" Here, we hypothesize that the molecular characteristics of patient HR+ tumors are key determinants to the tumor intake rate in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. Hence, reverse phase protein array (RPPA) analysis has be performed using human patient tumors to identify driver-pathways that impact tumor intake in NSG mice.

Results and Discussion: We compared the protein expression profile of six HR+ patient tumors (four HR+ and two HR+ HER2+), which were successfully engrafted into NSG mice and established as PDX models, with the patient tumors which we were unable to establish as PDX. Of 90 patient HR+ tumors which failed to transplant, 21 tumors were picked to match the tumor type (all of them were invasive ductal carcinoma or its metastases), clinical stage and pathological grade of engrafted tumors [Table 1]. In addition to patient tumors, six established HR+ PDXs were also submitted for analysis. Quantified expressions of 272 cancer-related proteins and phospho-proteins by RPPA have been performed on these specimens. Pathways identified as predictors of intake rate of PDXs in NSG mice, and tissues from paired PDX from mice with different passages, will be evaluated for the protein expression changes to elucidate the passage effects and generate therapeutic models based on protein expression and tumor growth.

Table 1. Characteristics of the patient tumors which were successfully established as PDX modelsERPgRHER2AgePatient ethnicityClinical stageNottingham histologic scoreSource++-63Hispanic3IIIBreast tumor+--71Hispanic2IIIBreast tumor+--52African-american4N/ABrain mets+--63Caucasian4N/AChest wall mets+-+34Caucasian2IIBreast tumor+++72Caucasian4IIIChest wall metsmets: metastases

Citation Format: Kanaya N, Somlo G, Wu J, Frankel P, Wu SV, Nguyen D, Kai M, Chan N, Meng-Yin H, Kirschenbaum M, Kruper L, Vito C, Yuan Y, Hurria A, Mortimer J, Chen S. Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-03-02.

Clinical utility of neuronal cells directly converted from fibroblasts of patients for neuropsychiatric disorders: studies of lysosomal storage diseases and channelopathy

Methodologies for generating functional neuronal cells directly from human fibroblasts [induced neuronal (iN) cells] have been recently developed, but the research so far has only focused on technical refinements or recapitulation of known pathological phenotypes. A critical question is whether this novel technology will contribute to elucidation of novel disease mechanisms or evaluation of therapeutic strategies. Here we have addressed this question by studying Tay-Sachs disease, a representative lysosomal storage disease, and Dravet syndrome, a form of severe myoclonic epilepsy in infancy, using human iN cells with feature of immature postmitotic glutamatergic neuronal cells. In Tay-Sachs disease, we have successfully characterized canonical neuronal pathology, massive accumulation of GM2 ganglioside, and demonstrated the suitability of this novel cell culture for future drug screening. In Dravet syndrome, we have identified a novel functional phenotype that was not suggested by studies of classical mouse models and human autopsied brains. Taken together, the present study demonstrates that human iN cells are useful for translational neuroscience research to explore novel disease mechanisms and evaluate therapeutic compounds. In the future, research using human iN cells with well-characterized genomic landscape can be integrated into multidisciplinary patient-oriented research on neuropsychiatric disorders to address novel disease mechanisms and evaluate therapeutic strategies.

Calculating disability-adjusted life years (DALY) as a measure of excess cancer risk following radiation exposure

This paper has proposed that disability-adjusted life year (DALY) can be used as a measure of radiation health risk. DALY is calculated as the sum of years of life lost (YLL) and years lived with disability (YLD). This multidimensional concept can be expressed as a risk index without a probability measure to avoid the misuse of the current radiation detriment at low doses. In this study, we calculated YLL and YLD using Japanese population data by gender. DALY for all cancers in Japan per 1 Gy per person was 0.84 year in men and 1.34 year in women. The DALY for all cancers in the Japanese baseline was 4.8 in men and 3.5 in women. When we calculated the ICRP detriment from the same data, DALYs for the cancer sites were similar to the radiation detriment in the cancer sites, excluding leukemia, breast and thyroid cancer. These results suggested that the ICRP detriment overestimate the weighting fraction of leukemia risk and underestimate the weighting fraction of breast and thyroid cancer. A big advantage over the ICRP detriment is that DALY can calculate the risk components for non-fatal diseases without the data of lethality. This study showed that DALY is a practical tool that can compare many types of diseases encountered in public health.

The checkpoint clamp protein Rad9 facilitates DNA-end resection and prevents alternative non-homologous end joining

DNA damage activates the cell cycle checkpoint to regulate cell cycle progression. The checkpoint clamp (Rad9-Hus1-Rad1 complex) is recruited to damage sites, and is required for checkpoint activation. While functions of the checkpoint clamp in checkpoint activation have been well studied, its functions in DNA repair regulation remain elusive. Here we show that Rad9 is required for efficient homologous recombination (HR), and facilitates DNA-end resection. The role of Rad9 in homologous recombination is independent of its function in checkpoint activation, and this function is important for preventing alternative non-homologous end joining (altNHEJ). These findings reveal novel function of the checkpoint clamp in HR.