Tibetans exhibit lower hemoglobin concentration and decreased heart response to hypoxia during poikilocapnia at intermediate altitude relative to Han Chinese

Background

High-altitude populations exhibit distinct cellular, respiratory, and cardiovascular phenotypes, some of which provide adaptive advantages to hypoxic conditions compared to populations with sea-level ancestry. Studies performed in populations with a history of high-altitude residence, such as Tibetans, support the idea that many of these phenotypes may be shaped by genomic features that have been positively selected for throughout generations. We hypothesize that such traits observed in Tibetans at high altitude also occur in Tibetans living at intermediate altitude, even in the absence of severe sustained hypoxia.

Methodology

We studied individuals of high-altitude ancestry (Tibetans, n = 17 females; n = 12 males) and sea-level ancestry (Han Chinese, n = 6 females; n = 10 males), both who had been living at ∼1300 m (∼4327 ft) for at least 18 months. We measured hemoglobin concentration ([Hb]), hypoxic ventilatory response (HVR), and hypoxic heart rate response (HHRR) with end-tidal CO2 (PetCO2) held constant (isocapnia) or allowed to decrease with hypoxic hyperventilation (poikilocapnia). We also quantified the contribution of CO2 on ventilation and heart rate by calculating the differences of isocapnic versus poikilocapnic hypoxic conditions (Δ V ˙ I /ΔPetCO2 and ΔHR/ΔPetCO2, respectively).

Results

Male Tibetans had lower [Hb] compared to Han Chinese males (p < 0.05), consistent with reports for individuals from these populations living at high altitude and sea level. Measurements of ventilation (resting ventilation, HVR, and PetCO2) were similar for both groups. Heart rate responses to hypoxia were similar in both groups during isocapnia; however, HHRR in poikilocapnia was reduced in the Tibetan group (p < 0.03), and the heart rate response to CO2 in hypoxia was lower in Tibetans relative to Han Chinese (p < 0.01).

Conclusion

These results suggest that Tibetans living at intermediate altitude have blunted cardiac responses in the context of hypoxia. Hence, only some of the phenotypes observed in Tibetans living at high altitude are observed in Tibetans living at intermediate altitude. Whereas blunted cardiac responses to hypoxia is revealed at intermediate altitudes, manifestation of other physiological adaptations to high altitude may require exposure to more severe levels of hypoxia.

Unraveling sources of emission heterogeneity in Silicon Vacancy color centers with cryo-cathodoluminescence microscopy

Diamond color centers have proven to be versatile quantum emitters and exquisite sensors of stress, temperature, electric and magnetic fields, and biochemical processes. Among color centers, the silicon-vacancy (SiV[Formula: see text]) defect exhibits high brightness, minimal phonon coupling, narrow optical linewidths, and high degrees of photon indistinguishability. Yet the creation of reliable and scalable SiV[Formula: see text]-based color centers has been hampered by heterogeneous emission, theorized to originate from surface imperfections, crystal lattice strain, defect symmetry, or other lattice impurities. Here, we advance high-resolution cryo-electron microscopy combined with cathodoluminescence spectroscopy and 4D scanning transmission electron microscopy (STEM) to elucidate the structural sources of heterogeneity in SiV[Formula: see text] emission from nanodiamond with sub-nanometer-scale resolution. Our diamond nanoparticles are grown directly on TEM membranes from molecular-level seedings, representing the natural formation conditions of color centers in diamond. We show that individual subcrystallites within a single nanodiamond exhibit distinct zero-phonon line (ZPL) energies and differences in brightness that can vary by 0.1 meV in energy and over 70% in brightness. These changes are correlated with the atomic-scale lattice structure. We find that ZPL blue-shifts result from tensile strain, while ZPL red shifts are due to compressive strain. We also find that distinct crystallites host distinct densities of SiV[Formula: see text] emitters and that grain boundaries impact SiV[Formula: see text] emission significantly. Finally, we interrogate nanodiamonds as small as 40 nm in diameter and show that these diamonds exhibit no spatial change to their ZPL energy. Our work provides a foundation for atomic-scale structure-emission correlation, e.g., of single atomic defects in a range of quantum and two-dimensional materials.

Characterizing prescription opioid, heroin, and fentanyl initiation trajectories: A qualitative study

We understand the current crisis of overdose deaths to be driven by widespread opioid use, characterized by distinct 'waves' of drug use. The first wave was driven by prescription opioids, the second by heroin, and the third by illicit, non-pharmaceutical fentanyl and fentanyl analogues (henceforth, fentanyl). The purpose of this study is to describe opioid initiation within each of the three waves from the perspective of people who use illicit opioids, with a focus on emerging pathways into fentanyl use. The authors recruited sixty people reporting past-30-day illicit opioid use in Dayton, Ohio. Participants completed a brief survey and a semi-structured in-depth qualitative interview, conducted from March to November 2020 with a total of 13 in-person and 47 virtual interviews. The qualitative interviews were transcribed in their entirety and analyzed thematically using NVivo 12. We noted supply-side changes as influencing trajectories in all three waves. However, we also noted differences in the experiences of prescription opioid and heroin initiation, with these trajectories influenced by pharmacological effects, pain management, curiosity, intergenerational use, pricing, and peers. In comparison, most participants were unaware that they were initiating fentanyl, and many reported overdosing with their first use of fentanyl. We identified a trajectory into fentanyl with limited to no prior heroin use among a few participants. The increased risk of overdose with initiation into fentanyl use further emphasizes the need for an expansion of naloxone distribution and the implementation of more comprehensive measures, such as overdose prevention centers, drug testing, and a safer supply. Further research on the dynamics of the ongoing overdose death crisis in the era of fentanyl and the 4th wave of the overdose crisis is critical in developing responsive prevention and intervention strategies.

Long-term changes of Th17 and regulatory T cells in peripheral blood of dogs with spinal cord injury after intervertebral disc herniation

BACKGROUND

Intervertebral disc herniation (IVDH) is one of the most common causes of spinal cord injury (SCI) in dogs. As a result of acute SCI, a complex inflammatory response occurs in the spinal cord. Th17 cells (Th17) produce pro-inflammatory cytokines, while regulatory T cells (Treg) have opposite effects producing anti-inflammatory cytokines. Therefore, the aim of this study was to determine whether Th17- and Treg cells are involved in the pathogenesis of SCI or whether cellular changes occur due to coexisting inflammatory diseases. We hypothesized that chronic alterations in the Th17/Treg ratio are associated with a worse outcome after SCI.

METHODS

Twenty-six paretic or plegic dogs with IVDH with and without coexisting inflammatory disease were investigated in the acute stage of the disease and after recovery of SCI. In addition, a healthy control group was included (n = 14). Quantification of Th17 and Treg cells, from peripheral blood samples, was performed by multicolor flow cytometry and IL17 was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

After recovery significantly higher levels of Th17 (p = 0.0265) and Treg cells (p = 0.00025) were detected compared to acute IVDH but Th17/Treg ratio did not differ significantly. Recovered dogs and the control group did not differ significantly from each other. No association between an imbalance in the ratio and neurologic severity or underlying inflammatory diseases was found.

CONCLUSION

This study demonstrated that altered Th17 and Treg levels in peripheral blood are altered in the acute stage of IVDH, preexisting inflammatory diseases seem not to influence these cell populations. Th17 and Treg cells could be considered when evaluating new treatment strategies for SCI.

Measurement of canine Th17 cells by flow cytometry

Th17 cells are T helper cells which play an important role during inflammation and autoimmune disease. To investigate the role of these cells in diseases in dogs in a clinical setting, methods for fast identification had to be established. Th17 cells are a rare cell population, for their measurement stimulation is recommended. To examine more samples simultaneously and to receive a relatively high purity of cell population of CD3 + CD4+ cells, different methods on various levels of preselection of cells as well as the possibility of storing blood overnight for measuring Th17 cells by flow cytometry were investigated. Firstly, to receive a high number of mononuclear cells, two different density gradients were compared and analysed. Furthermore, the enrichment of CD3 + CD4+ cells via depletion of CD8alpha+, CD11b + and CD21+ cells by cell sorting (autoMACS Pro Separator) was tested. It was also investigated whether stimulation processes led to better interpretation of results and whether there was a significant difference in measurement of directly processed blood samples and samples that had been stored overnight. In conclusion, the use of the density gradient (Lymph24+ Spin Medium) resulted in a purer cell population through a significant decrease in polymorphonuclear cells (*p = 0.01). After cell sorting, a significant difference in cell population purity was detected. Within the target fraction (containing mainly CD3 + CD4+ cells), CD8alpha+, CD21+, CD11b + cell percentages were significantly lower (***p < 0.001, *p < 0.02, ***p < .0001, respectively), and CD3 + CD4+ cell percentage was significantly higher (***p < .0001). There was a significant difference in Th17 cell percentage between unstimulated and stimulated cell populations (***p < .0001), but no significant difference in the percentage of unstimulated Th17 cells (p = 0.29) or stimulated Th17 cells (p = 0.71) in stored blood in comparison to directly processed EDTA blood samples. Finally, a modified protocol that offers an efficient way to investigate samples that were stored overnight by means of flow cytometry was evolved to research the role of Th17 cells in dogs with different diseases or in healthy populations.

1354. Antibiotic Resistance and Coinfections Among Women with Sexually Transmitted Infections

Background

Sexually transmitted infections (STIs) represent a growing epidemic, particularly among America’s youth. Traditional single or dual organism STI testing is limited in its utility compared to PCR panel-based vaginitis testing. PCR panel testing can identify up to 99% of vaginitis associated organisms, while simultaneously providing information about antibiotic resistance.

Methods

We analyzed 10,011 vaginosis panel cases released between April 2020 and May 2021. The PCR-based vaginosis panel consists of organisms associated with bacterial vaginosis, aerobic vaginitis, yeast infections, STIs, and Lactobacillus species. This panel simultaneously detects evidence of antibiotic resistance for nine classes of drugs.

Results

Of 9405 cases from vaginal swabs, 618 (6.8%) were positive for at least one STI including Chlamydia trachomatis (CT), Haemophilus ducreyi, Herpes Simplex Virus 1 or 2 (HSV2), Neisseria gonorrhoeae (NG), and/or Trichomonas vaginalis. Of 603 urine samples, 7.6% were positive for at least one STI and represented a younger population. Patients younger than age 25 (33% of the cohort) were disproportionately affected by STIs, consistent with CDC findings. About 50% of all positive STI cases were in patients under 25. Evidence of bacterial vaginosis was also present in 89% of CT and NG cases, and 75% of HSV2 cases. Strikingly, we found the presence of an antibiotic resistant marker(s) to first line treatment in 76.2% of CT and 19.3% of NG cases.

Conclusion

Our data illustrates the advantages of utilizing a PCR-panel approach to STI detection over a targeted approach for individual organisms. Coinfections with bacterial vaginosis were common and if left unidentified, patients may receive incomplete treatment. Additionally, our data suggests that antibiotic resistance testing is imperative for effective treatment planning and antibiotic stewardship in suspected STI cases.

Disclosures

Brittany L. Carpenter, PhD, NxGen MDx (Employee) Jacqueline D. Peacock, PhD, MB(ASCP)CM, NxGen MDx (Employee) Kyle Dubiak, PhD, NxGen MDx (Employee) Heather Fecteau, MS, LCGC, NxGen MDx (Employee) Robert Carlson, MD, FCAP, NxGen MDx (Employee)

Chimeric Ad5.F35 vector evades anti-adenovirus serotype 5 neutralization opposing GUCY2C-targeted antitumor immunity

BACKGROUND

Adenovirus serotype 5 (Ad5) is a commonly used viral vector for transient delivery of transgenes, primarily for vaccination against pathogen and tumor antigens. However, endemic infections with Ad5 produce virus-specific neutralizing antibodies (NAbs) that limit transgene delivery and constrain target-directed immunity following exposure to Ad5-based vaccines. Indeed, clinical trials have revealed the limitations that virus-specific NAbs impose on the efficacy of Ad5-based vaccines. In that context, the emerging focus on immunological approaches targeting cancer self-antigens or neoepitopes underscores the unmet therapeutic need for more efficacious vaccine vectors.

METHODS

Here, we evaluated the ability of a chimeric adenoviral vector (Ad5.F35) derived from the capsid of Ad5 and fiber of the rare adenovirus serotype 35 (Ad35) to induce immune responses to the tumor-associated antigen guanylyl cyclase C (GUCY2C).

RESULTS

In the absence of pre-existing immunity to Ad5, GUCY2C-specific T-cell responses and antitumor efficacy induced by Ad5.F35 were comparable to Ad5 in a mouse model of metastatic colorectal cancer. Furthermore, like Ad5, Ad5.F35 vector expressing GUCY2C was safe and produced no toxicity in tissues with, or without, GUCY2C expression. Importantly, this chimeric vector resisted neutralization in Ad5-immunized mice and by sera collected from patients with colorectal cancer naturally exposed to Ad5.

CONCLUSIONS

These data suggest that Ad5.F35-based vaccines targeting GUCY2C, or other tumor or pathogen antigens, may produce clinically relevant immune responses in more (≥90%) patients compared with Ad5-based vaccines (~50%).

Defining current gaps in quality measures for cancer immunotherapy: consensus report from the Society for Immunotherapy of Cancer (SITC) 2019 Quality Summit

BACKGROUND

Quality measures are important because they can help improve and standardize the delivery of cancer care among healthcare providers and across tumor types. In an environment characterized by a rapidly shifting immunotherapeutic landscape and lack of associated long-term outcome data, defining quality measures for cancer immunotherapy is a high priority yet fraught with many challenges.

METHODS

Thus, the Society for Immunotherapy of Cancer convened a multistakeholder expert panel to, first, identify the current gaps in measures of quality cancer care delivery as it relates to immunotherapy and to, second, advance priority concepts surrounding quality measures that could be developed and broadly adopted by the field.

RESULTS

After reviewing the existing quality measure landscape employed for immunotherapeutic-based cancer care, the expert panel identified four relevant National Quality Strategy domains (patient safety, person and family-centered care, care coordination and communication, appropriate treatment selection) with significant gaps in immunotherapy-based quality cancer care delivery. Furthermore, these domains offer opportunities for the development of quality measures as they relate to cancer immunotherapy. These four quality measure concepts are presented in this consensus statement.

CONCLUSIONS

This work represents a first step toward defining and standardizing quality delivery of cancer immunotherapy in order to realize its optimal application and benefit for patients.

Toward Optimization of Cancer Care in Sub-Saharan Africa: Development of National Comprehensive Cancer Network Harmonized Guidelines for Sub-Saharan Africa

PURPOSE

Standard treatment guidelines improve patient outcomes, including disease-specific survival, in cancer care. The African Cancer Coalition was formed in 2016 to harmonize cancer treatment guidelines for sub-Saharan Africa.

METHODS

The African Cancer Coalition collaborated with the National Comprehensive Cancer Network (NCCN) and the American Cancer Society to harmonize 46 cancer treatment guidelines for use in sub-Saharan Africa. Harmonization for each guideline was completed by a group of approximately 6-10 African cancer experts from a range of specialties and with representation across resource levels. Each working group was chaired by an African oncologist and included a member of the appropriate NCCN guidelines panel. Treatment recommendations from the parent guidelines were distinguished as options that are generally available and should be considered standard care in most of the region or as highly advanced options for which cost or other resources may limit widespread availability. Additional recommendations specific to sub-Saharan Africa were added.

RESULTS

The NCCN Harmonized Guidelines for sub-Saharan Africa, available for download on the NCCN website and mobile application, provide flexible recommendations appropriate for the range of resources seen in African cancer programs, from private comprehensive cancer centers to resource-constrained public hospitals. IBM (Armonk, NY) has developed a digital interface—the Cancer Guidelines Navigator—that allows oncologists to access the treatment recommendations for the first five guidelines through an interactive web-based application.

CONCLUSION

Harmonized guidelines that reflect the diversity of resource levels that characterize the current state of clinical care for cancer in Africa have the potential to fill a crucial gap in efforts to standardize and improve cancer care in Africa.

Characterizing Trends in Synthetic Cannabinoid Receptor Agonist Use from Patient Clinical Evaluations during Medical Toxicology Consultation

Synthetic cannabinoid receptor agonists (SCRAs) are a new class of compounds with profound psychoactive effects and potential toxicity. This study characterizes patterns in SCRA abuse using qualitative interviews with individuals receiving medical toxicology consultation. Patients with suspected exposure to a new psychoactive substance were interviewed by medical toxicologists upon presentation for acute care. Investigators collected clinical and qualitative data including knowledge, attitudes, beliefs, and practices related to psychoactive substance use. Responses were categorized by identifying themes, and statistics were generated to describe patterns of use. Overall, 69% (86) of the 124 cases of novel psychoactive substance use entered into the registry were associated with exposure to SCRAs. Most patients (68.8%) had used SCRAs at least once before the presenting episode. 47.7% considered SCRAs to be very easy to obtain, and 44.2% reported paying for the substances while 32.6% acquired it for free. Nearly half (48.8%) of patients reported their primary reason for use was to get high; a small proportion used SCRAs to avoid testing positive on drug screening (6.9%) or as an alternative to marijuana (4.6%). Findings suggest an independent and stable culture is developing around the use of SCRAs separate from their appeal as an "undetectable" alternative to marijuana.

Chimeric Antigen Receptor T-Cell Therapy

Patients with relapsed or refractory (R/R) cancers have a poor prognosis and limited treatment options. The recent approval of 2 chimeric antigen receptor (CAR) autologous T-cell products for R/R B-cell acute lymphoblastic leukemia and non-Hodgkin's lymphoma treatment is setting the stage for what is possible in other diseases. However, there are important factors that must be considered, including patient selection, toxicity management, and costs associated with CAR T-cell therapy. To begin to address these issues, NCCN organized a task force consisting of a multidisciplinary panel of experts in oncology, cancer center administration, and health policy, which met for the first time in March 2018. This report describes the current state of CAR T-cell therapy and future strategies that should be considered as the application of this novel immunotherapy expands and evolves.

National Comprehensive Cancer Network: Global Utilization of Clinical Oncology Guidelines

Background: The global influence and demand for clinical oncology guidelines is increasing. National Comprehensive Cancer Network (NCCN), American Society of Clinical Oncology (ASCO), European Society of Medical Oncology (ESMO), and various other organizations develop clinical oncology guidelines, which are used across regions to provide evidence-based recommendations for the management of cancer.1 Aim: To identify and analyze utilization trends of clinical oncology guidelines outside the US. Methods: In 2017, NCCN distributed an electronic survey to 212,423 registered users of the NCCN Web site outside the US through a third party software. Participants were prompted to respond to the following statement “I consult the following guidelines regularly: (Select all that apply).” Options included several clinical oncology guidelines, as well as the option “I do not regularly consult clinical oncology guidelines.” The survey also included the following query: “In my opinion, the NCCN Guidelines are: (select one per row).” The survey then listed several descriptors and the respondents were asked to select strongly agree, agree, no opinion, disagree, or strongly disagree for each one. Results: NCCN received 1698 responses to the survey from oncology professionals outside of the US. Of this pool, 82% of respondents identified as physicians and 18% were other oncology professionals. Of respondents to the first query (n=1190), 89% selected the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines), 55% ESMO Clinical Practice Guidelines, 50% ASCO Guidelines, 20% National Institute for Health and Care Excellence (NICE) guidelines, 15% local, national, or other oncology guidelines, 11% Sociedad Española de Oncología Médica (SEOM), 8% Cancer Care Ontario Guidelines, 7% Multinational Association of Supportive Care in Cancer (MASCC), 6% Japanese Society of Medical Oncology Clinical Guidelines, and 6% do not regularly consult clinical oncology guidelines. In response to the second query (n=1392), more than 90% of respondents outside of the US “strongly agree” or “agree” that the NCCN Guidelines are useful in patient care decision-making, a reliable reference, up-to-date, objective and balanced, evidence-based, and helpful in clinical teaching. Conclusion: Based on data presented, NCCN Guidelines are consulted more frequently than any other clinical oncology guideline outside the US. Previous research indicates similar utilization trends. We believe, in part, healthcare professionals outside the US consult the NCCN Guidelines frequently due to the descriptors listed in the survey results. Additional research is needed to identify the synergies between the relevance of international clinical oncology guidelines and local utilization trends to better serve the needs of patients globally.

Random access in large-scale DNA data storage

Synthetic DNA is durable and can encode digital data with high density, making it an attractive medium for data storage. However, recovering stored data on a large-scale currently requires all the DNA in a pool to be sequenced, even if only a subset of the information needs to be extracted. Here, we encode and store 35 distinct files (over 200 MB of data), in more than 13 million DNA oligonucleotides, and show that we can recover each file individually and with no errors, using a random access approach. We design and validate a large library of primers that enable individual recovery of all files stored within the DNA. We also develop an algorithm that greatly reduces the sequencing read coverage required for error-free decoding by maximizing information from all sequence reads. These advances demonstrate a viable, large-scale system for DNA data storage and retrieval.

Intraoperative serum lactate is not a predictor of survival after glioblastoma surgery

BACKGROUND

Cancer cells can produce lactate in high concentrations. Two previous studies examined the clinical relevance of serum lactate as a biomarker in patients with brain tumors. Patients with high-grade tumors have higher serum concentrations of lactate than those with low-grade tumors. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB).

METHODS

This was a retrospective study. Demographic, lactate concentrations and imaging data from 275 adult patients with primary GB was included in the analysis. The progression free survival (PFS) and overall survival (OS) rates were compared in patients who had above and below the median concentrations of lactate. We also investigated the correlation between lactate concentrations and tumor volume. Multivariate analyses were conducted to test the association lactate, tumor volume and demographic variables with PFS and OS.

RESULTS

The median serum concentration of lactate was 2.3mmol/L. A weak correlation was found between lactate concentrations and tumor volume. Kaplan-Meier curves demonstrated similar survival in patients with higher or lower than 2.3mmol/L of lactate. The multivariate analysis indicated that the intraoperative levels of lactate were not independently associated with changes in survival. On another hand, a preoperative T1 volume was an independent predictor PFS (HR 95%CI: 1.41, 1.02-1.82, p=0.006) and OS (HR 95%CI: 1.47, 1.11-1.96, p=0.006).

CONCLUSION

This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery. To date, there are no clinically available serum biomarkers to determine prognosis in patients with high-grade gliomas. These tumors may produce high levels of lactic acid. We hypothesized that serum lactic could be used of biomarker to predictor of survival in patients with glioblastoma (GB). In this study, we collected perioperative and survival data from 275 adult patients with primary high-grade gliomas to determine whether intraoperative serum acid lactic concentrations can serve as a marker of prognosis. The median serum concentration of lactate was 2.3mmol/L. Our analysis indicated the intraoperative levels of lactate were not independently associated with changes in survival. This retrospective study suggests that the serum concentrations of lactate cannot be used as a biomarker to predict survival after GB surgery.

Anti-tumor activity of selective inhibitor of nuclear export (SINE) compounds, is enhanced in non-Hodgkin lymphoma through combination with mTOR inhibitor and dexamethasone

In previous studies we demonstrated that targeting the nuclear exporter protein exportin-1 (CRM1/XPO1) by a selective inhibitor of nuclear export (SINE) compound is a viable therapeutic strategy against Non-Hodgkin Lymphoma (NHL). Our studies along with pre-clinical work from others led to the evaluation of the lead SINE compound, selinexor, in a phase 1 trial in patients with CLL or NHL (NCT02303392). Continuing our previous work, we studied combinations of selinexor-dexamethasone (DEX) and selinexor-everolimus (EVER) in NHL. Combination of selinexor with DEX or EVER resulted in enhanced cytotoxicity in WSU-DLCL2 and WSU-FSCCL cells which was consistent with enhanced apoptosis. Molecular analysis showed enhancement in the activation of apoptotic signaling and down-regulation of XPO1. This enhancement is consistent with the mechanism of action of these drugs in that both selinexor and DEX antagonize NF-κB (p65) and mTOR (EVER target) is an XPO1 cargo protein. SINE compounds, KPT-251 and KPT-276, showed activities similar to CHOP (cyclophosphamide-hydroxydaunorubicin-oncovin-prednisone) regimen in subcutaneous and disseminated NHL xenograft models in vivo. In both animal models the anti-lymphoma activity of selinexor is enhanced through combination with DEX or EVER. The in vivo activity of selinexor and related SINE compounds relative to 'standard of care' treatment is consistent with the objective responses observed in Phase I NHL patients treated with selinexor. Our pre-clinical data provide a rational basis for testing these combinations in Phase II NHL trials.

First-in-Class, First-in-Human Phase I Study of Selinexor, a Selective Inhibitor of Nuclear Export, in Patients With Advanced Solid Tumors

Purpose This trial evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of selinexor (KPT-330), a novel, oral small-molecule inhibitor of exportin 1 (XPO1/CRM1), and determined the recommended phase II dose. Patients and Methods In total, 189 patients with advanced solid tumors received selinexor (3 to 85 mg/m2) in 21- or 28-day cycles. Pre- and post-treatment levels of XPO1 mRNA in patient-derived leukocytes were determined by reverse transcriptase quantitative polymerase chain reaction, and tumor biopsies were examined by immunohistochemistry for changes in markers consistent with XPO1 inhibition. Antitumor response was assessed according Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 guidelines. Results The most common treatment-related adverse events included fatigue (70%), nausea (70%), anorexia (66%), and vomiting (49%), which were generally grade 1 or 2. Most commonly reported grade 3 or 4 toxicities were thrombocytopenia (16%), fatigue (15%), and hyponatremia (13%). Clinically significant major organ or cumulative toxicities were rare. The maximum-tolerated dose was defined at 65 mg/m2 using a twice-a-week (days 1 and 3) dosing schedule. The recommended phase II dose of 35 mg/m2 given twice a week was chosen based on better patient tolerability and no demonstrable improvement in radiologic response or disease stabilization compared with higher doses. Pharmacokinetics were dose proportional, with no evidence of drug accumulation. Dose-dependent elevations in XPO1 mRNA in leukocytes were demonstrated up to a dose level of 28 mg/m2 before plateauing, and paired tumor biopsies showed nuclear accumulation of key tumor-suppressor proteins, reduction of cell proliferation, and induction of apoptosis. Among 157 patients evaluable for response, one complete and six partial responses were observed (n = 7, 4%), with 27 patients (17%) achieving stable disease for ≥ 4 months. Conclusion Selinexor is a novel and safe therapeutic with broad antitumor activity. Further interrogation into this class of therapy is warranted.

Antiviral Efficacy of Verdinexor In Vivo in Two Animal Models of Influenza A Virus Infection

Influenza A virus (IAV) causes seasonal epidemics of respiratory illness that can cause mild to severe illness and potentially death. Antiviral drugs are an important countermeasure against IAV; however, drug resistance has developed, thus new therapeutic approaches are being sought. Previously, we demonstrated the antiviral activity of a novel nuclear export inhibitor drug, verdinexor, to reduce influenza replication in vitro and pulmonary virus burden in mice. In this study, in vivo efficacy of verdinexor was further evaluated in two animal models or influenza virus infection, mice and ferrets. In mice, verdinexor was efficacious to limit virus shedding, reduce pulmonary pro-inflammatory cytokine expression, and moderate leukocyte infiltration into the bronchoalveolar space. Similarly, verdinexor-treated ferrets had reduced lung pathology, virus burden, and inflammatory cytokine expression in the nasal wash exudate. These findings support the anti-viral efficacy of verdinexor, and warrant its development as a novel antiviral therapeutic for influenza infection.

Phase IB Study of Selinexor, a First-in-Class Inhibitor of Nuclear Export, in Patients With Advanced Refractory Bone or Soft Tissue Sarcoma

PURPOSE

We evaluated the pharmacokinetics (PKs), pharmacodynamics, safety, and efficacy of selinexor, an oral selective inhibitor of nuclear export compound, in patients with advanced soft tissue or bone sarcoma with progressive disease.

PATIENTS AND METHODS

Fifty-four patients were treated with oral selinexor twice per week (on days 1 and 3) at one of three doses (30 mg/m(2), 50 mg/m(2), or flat dose of 60 mg) either continuously or on a schedule of 3 weeks on, 1 week off. PK analysis was performed under fasting and fed states (low v high fat content) and using various formulations of selinexor (tablet, capsule, or suspension). Tumor biopsies before and during treatment were evaluated for pharmacodynamic changes.

RESULTS

The most commonly reported drug-related adverse events (grade 1 or 2) were nausea, vomiting, anorexia, and fatigue, which were well managed with supportive care. Commonly reported grade 3 or 4 toxicities were fatigue, thrombocytopenia, anemia, lymphopenia, and leukopenia. Selinexor was significantly better tolerated when administered as a flat dose on an intermittent schedule. PK analysis of selinexor revealed a clinically insignificant increase (approximately 15% to 20%) in drug exposure when taken with food. Immunohistochemical analysis of paired tumor biopsies revealed increased nuclear accumulation of tumor suppressor proteins, decreased cell proliferation, increased apoptosis, and stromal deposition. Of the 52 patients evaluable for response, none experienced an objective response by RECIST (version 1.1); however, 17 (33%) showed durable (≥ 4 months) stable disease, including seven (47%) of 15 evaluable patients with dedifferentiated liposarcoma.

CONCLUSION

Selinexor was well tolerated at a 60-mg flat dose on a 3-weeks-on, 1-week-off schedule. There was no clinically meaningful impact of food on PKs. Preliminary evidence of anticancer activity in sarcoma was demonstrated.

Abstract 2319: Selinexor, a selective inhibitor of nuclear export (SINE), enhances the in vivo efficacy of checkpoint blockade with antibodies targeting CTLA4 or PD-1/PD-L1 in melanoma

Selinexor is a SINE (Selective Inhibitor of Nuclear Export) compound that has been administered to &gt;1000 cancer patients in Phase I and II trials to date, with evidence of efficacy and tolerability. This small molecule targets exportin-1 (XPO1), a key nuclear export protein with &gt;200 cargo proteins which include both tumor suppressors and cell cycle modulators. As a result, selinexor blocks nuclear export of proteins including IκB, NFAT1c, STAT1 and STAT3, which regulate expression of the inhibitory T cell receptors CTLA4, PD1 and its ligand, PD-L1. We hypothesized that selinexor would upregulate T cell checkpoint molecule expression, and thereby enhance the anti-tumor activity of antibodies targeting PD-1/PD-L1 or CTLA4. Human (A375, CHL-1) and murine (B16F10) melanoma cell lines expressed high levels of PD-L1 protein at baseline, and PD-L1 expression was induced following selinexor treatment in numerous other tumor cell lines (including HCT-116, MDA-MB-468, MV-4-11, OVCAR-8, and PC-3). Examination of lymphocytes revealed that selinexor also increased expression of PD-1 and CTLA4 by ∼2-fold. Mice bearing syngeneic B16F10 melanoma tumors treated with selinexor (15 mg/kg 2 x weekly) and anti-CTLA4 (250 μg, 2 x weekly) demonstrated a significant reduction in tumor growth rate (p = 0.0065) while monotherapy had no significant effect on tumor growth. Similar results were obtained in mice bearing B16F10 melanoma treated with the combination of selinexor + anti-PD-1 (200 μg, 2 x weekly, p &lt; 0.034) or selinexor + anti-PD-L1 (100-200 μg, 2 x weekly, p &lt; 0.001). Importantly, no weight loss or signs of toxicity were evident in any in vivo study. Further immunophenotypic analyses have been completed in animals receiving selinexor alone or in combination with anti-PD-L1. In combination treated mice, we observed a significantly increased percentage of splenic NK cells (p ≤ 0.050), and a significantly increased percentage of splenic Th1 T cells (p≤0.011), all compared to vehicle treated mice. Interestingly, combining selinexor with anti-PD-L1 significantly decreased the percentage of splenocytes that expressed PD-L1 (p&lt;0.001). These changes are indicative of increased anti-tumor immune activity; however, they were accompanied by significantly increased percentages of myeloid cell subsets in combination treated mice (p ≤ 0.050). The immunologic significance of this myeloid cell expansion is currently under investigation. These data indicate that the efficacy of selinexor may be enhanced by disrupting immune checkpoints in effector cells (T and NK cells). This provides data in support of novel, evidenced-based combinations involving immunotherapy with XPO1 inhibition that deserve further investigation for advanced cancer.

Citation Format: Matthew R. Farren, Reena Shakya, Rebecca Hennessey, Thomas Mace, Jennifer Yang, Omar Elnaggar, Gregory Young, Yosef Landesman, Robert Carlson, Sivan Elloul, Marsha Crochiere, Christin Burd, Gregory B. Lesinski. Selinexor, a selective inhibitor of nuclear export (SINE), enhances the in vivo efficacy of checkpoint blockade with antibodies targeting CTLA4 or PD-1/PD-L1 in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2319.

Importance of Surgical Margin Status in Ductal Carcinoma In Situ

BACKGROUND

The purpose of the study was to identify the effect of final surgical margin (SM) status and re-excision on outcomes in patients with ductal carcinoma in situ (DCIS) who underwent breast conservation therapy (BCT).

PATIENTS AND METHODS

The study population consisted of women diagnosed with DCIS who underwent BCT between 1989 and 2014. All women received adjuvant whole breast radiation and a boost. The primary end point was local control (LC). Final SMs were defined according to margin width: negative SM was defined as > 2 mm, close SM was defined as > 0 to ≤ 2 mm, and a positive SM was defined as tumor on ink. The Cox proportional hazards model was used to determine predictors of outcomes on multivariable analysis. Actuarial incidence of LC was estimated using the Kaplan-Meier method.

RESULTS

A total of 498 patients were included; 400 patients had a final negative SM, 87 had a close SM, and 11 had a positive SM. A total of 172 patients received adjuvant hormonal therapy, 265 patients required ≥ 1 re-excision. Patients with positive or close SMs were more likely to receive a radiation dose > 60 Gy (P < .001) and undergo re-excision (P < .01). The 10-year LC rates were not significantly different between patients with a negative (93.5%), close (91.8%), or positive (100%) SM (P = .57). There was no difference in LC in patients who underwent re-excision for initial close or positive SMs (P = .55).

CONCLUSION

This single-institution experience showed that risks of local recurrence remain poorly characterized. Re-excision and whole breast radiation with boost resulted in excellent LC for women with DCIS. Trials aimed at personalized deintensified local therapy are warranted.

A Nuclear Attack on Traumatic Brain Injury: Sequestration of Cell Death in the Nucleus

Background

Exportin 1 (XPO1/CRM1) plays prominent roles in the regulation of nuclear protein export. Selective inhibitors of nuclear export (SINE) are small orally bioavailable molecules that serve as drug‐like inhibitors of XPO1, with potent anti‐cancer properties. Traumatic brain injury (TBI) presents with a secondary cell death characterized by neuroinflammation that is putatively regulated by nuclear receptors.

Aims and Results

Here, we report that the SINE compounds (KPT‐350 or KPT‐335) sequestered TBI‐induced neuroinflammation‐related proteins (NF‐_kB, AKT, FOXP1) within the nucleus of cultured primary rat cortical neurons, which coincided with protection against TNF‐α (20 ng/mL)‐induced neurotoxicity as shown by at least 50% and 100% increments in preservation of cell viability and cellular enzymatic activity, respectively, compared to non‐treated neuronal cells (P's < 0.05). In parallel, using an in vivo controlled cortical impact (CCI) model of TBI, we demonstrate that adult Sprague‐Dawley rats treated post‐injury with SINE compounds exhibited significant reductions in TBI‐induced behavioral and histological deficits. Animals that received KPT‐350 orally starting at 2 h post‐TBI and once a day thereafter over the next 4 days exhibited significantly better motor coordination, and balance in the rotorod test and motor asymmetry test by 100–200% improvements, as early as 4 h after initial SINE compound injection that was sustained during subsequent KPT‐350 dosing, and throughout the 18‐day post‐TBI study period compared to vehicle treatment (P's < 0.05). Moreover, KPT‐350 reduced cortical core impact area and peri‐impact cell death compared to vehicle treatment (P's < 0.05).

Conclusions

Both in vitro and in vivo experiments revealed that KPT‐350 increased XPO1, AKT, and FOXP1 nuclear expression and relegated NF‐_kB expression within the neuronal nuclei. Altogether, these findings advance the utility of SINE compounds to stop trafficking of cell death proteins within the nucleus as an efficacious treatment for TBI.

Discovery of an L-alanine ester prodrug of the Hsp90 inhibitor, MPC-3100

Various types of Hsp90 inhibitors have been and continue to undergo clinical investigation. One development candidate is the purine-based, synthetic Hsp90 inhibitor 1 (MPC-3100), which successfully completed a phase I clinical study. However, further clinical development of 1 was hindered by poor solubility and consequent formulation issues and promoted development of a more water soluble prodrug. Towards this end, numerous pro-moieties were explored in vitro and in vivo. These studies resulted in identification of L-alanine ester mesylate, 2i (MPC-0767), which exhibited improved aqueous solubility, adequate chemical stability, and rapid bioconversion without the need for solubilizing excipients. Based on improved physical characteristics and favorable PK and PD profiles, 2i mesylate was selected for further development. A convergent, scalable, chromatography-free synthesis for 2i mesylate was developed to support further clinical evaluation.

Abstract 5472: Selinexor, a selective inhibitor of nuclear export (SINE), acts through NF-κB deactivation and combines with proteasome inhibitors to synergistically induce tumor cell death

Background: The primary nuclear export protein, Exportin 1 (XPO1/CRM1) is overexpressed in most cancers, which frequently correlates with poor prognosis. SINE compounds are a family of small-molecule bioavailable drugs that bind covalently to XPO1 leading to nuclear retention of major tumor suppressor proteins such as p53 and IκB, resulting in selective tumor cell death. Selinexor is the most advanced SINE with &gt;500 hematological and solid tumor cancer patients treated to date in Phase I/II clinical trials. Here we investigated the role of NF-κB transcriptional deactivation in SINE induced anti tumor activity by nuclear retention of IκB. We report the results of combining selinexor or related SINE compounds with proteasome inhibitors, for which inhibition of NF-κB has also been shown to be an important mechanism for cancer cell killing.

Methods: Whole protein cell lysates from solid and hematological cancer cell lines treated with selinexor with or without proteasome inhibitors were analyzed by immunoblots. IκB localization was evaluated by immunofluorescence. Cytotoxic effects of SINE compounds were evaluated in the presence or absence of proteasome inhibitors. NF-κB transcriptional activity was analyzed using an ELISA assay. H929 multiple myeloma xenografts in NOD-SCID mice were treated with selinexor alone or in combination with carfilzomib to determine effects on tumor growth.

Results: NF-κB transcriptional activity was upregulated in SINE resistant sarcoma cell lines HT1080R (IC50 = 2.4 μM versus HT1080 parental IC50 = 0.03 μM) and ASPS-KY (IC50&gt;10μM). In those resistant lines, combination of the proteasome inhibitors bortezomib or carfilzomib with SINE compound showed dramatic synergistic cytotoxic potency of more than 10 folds. Also, the combination of bortezomib with selinexor led to synergistic nuclear retention of IκB. Furthermore, IκB silencing by siRNA led to reduced selinexor cytotoxic potency, increasing IC50 from 58 nM to 830 nM (9-fold) in IM-9 multiple myeloma cells and from 27 nM to 1.9 μM (66-fold) in U2OS osteosarcoma cells. Finally, the combination of selinexor with carfilzomib was synergistic in reducing tumor growth in the H929 multiple myeloma xenograft model.

Conclusion: Inhibition of NF-κB transcriptional activity through forced nuclear retention of IκB appears to be an important mechanism in the selective tumor cell cytotoxicity of selinexor and related SINE compounds. Furthermore, the combination of selinexor and proteasome inhibitors, which are also known to act at least in part through inhibition of NF-κB, leads to synergistic activity in vitro and in vivo, suggesting that such combinations may provide clinically more effective than the single agents. A Phase 1 trial to study the safety and efficacy of selinexor in combination with carfilzomib in multiple myeloma is ongoing (NCT02199665).

Citation Format: Yosef Landesman, Trinayan Kashyap, Marsha Crochiere, Boris Klebanov, Sharon Friedlander, William Senapedis, Robert Carlson, Michael Kauffman, Sharon Shacham. Selinexor, a selective inhibitor of nuclear export (SINE), acts through NF-κB deactivation and combines with proteasome inhibitors to synergistically induce tumor cell death. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5472. doi:10.1158/1538-7445.AM2015-5472

Abstract 2074: Selective inhibitor of nuclear export (SINE) compounds show synergistic anti-tumor activity in combination with dexamethasone in multiple myeloma

Background: The primary nuclear export protein, Exportin 1 (XPO1/CRM1), is overexpressed in most cancers, which is frequently correlated with poor prognosis. SINE compounds are small-molecule bioavailable drugs that bind covalently to XPO1, which leads to nuclear retention of major tumor suppressor proteins, such as p53, FOXO and IκB, resulting in selective cancer cell death. Selinexor is the most advanced SINE with &gt;500 hematological and solid tumor cancer patients treated to date in Phase I/II clinical trials. Glucocorticoid Receptor (GR) is an XPO1 cargo and dexamethasone (Dex) acts through GR agonism and inhibition of NF-κB activity. The combination of selinexor with Dex seems likely to have enhanced anti-tumor potency and this hypothesis was tested in multiple myeloma models.

Methods: Total RNA and whole protein cell lysates from multiple myeloma cell line (MM1S) treated with selinexor with or without dexamethasone were analyzed by quantitative PCR and by immunoblots. Localization of GR was evaluated by immunofluorescence. GR and NF-κB transcriptional activity was analyzed using ELISA assays. MM1S xenograft model in NOD-SCID mice were treated with selinexor with or without dexamethasone to evaluate the effect on tumor growth.

Results: In MM.1S cells, we found Dex, but not selinexor, induced phosphorylation of GR resulting in GR nuclear localization. Selinexor prevented nuclear export of phosphorylated GR, leading to the synergistic induction of GR-dependent transcriptional activity. RNA levels of GR regulated genes such as MNK2 were induced by this combination treatment. Interestingly, between the two MNK2 isomers, the combination treatment increased the expression of MNK2α, which is a tumor suppressor protein but not the MNK2β isoform. NF-κB transcriptional activity was inhibited additively by this treatment in MM1S cells. The combination treatment of suboptimal doses of selinexor (5 mg/kg; 60% TGI) and Dex (1 mg/kg; 47% TGI) led to nearly complete growth suppression (91% TGI) in the MM1.S multiple myeloma xenografts.

Conclusions: We confirmed the hypothesized synergistic anti-tumor activity for the combination of selinexor with dexamethasone and provided evidence that this synergy is mediated through enhanced GR transcriptional activity, inhibition NF-κB and upregulation of the tumor suppressor MNK2α. This work provides a rationale basis for conducting clinical trials of combinations of selinexor with dexamethasone against cancers known to be sensitive to dexamethasone, such as multiple myeloma. Promising anti tumor activity for the combination of selinexor and dexamethasone in patients with relapsed/refractory MM was reported in the ongoing Phase 1 study (NCT01607892).

Citation Format: Yosef Landesman, Trinayan Kashyap, Boris Klebanov, Sivan Elloul, Marsha Crochiere, Sharon Friedlander, William Senapedis, Robert Carlson, Michael Kauffman, Sharon Shacham. Selective inhibitor of nuclear export (SINE) compounds show synergistic anti-tumor activity in combination with dexamethasone in multiple myeloma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2074. doi:10.1158/1538-7445.AM2015-2074

Abstract LB-255: Selinexor, a selective inhibitor of nuclear export (SINE) compound, shows enhanced antitumor activity in combination with the PARP inhibitor, olaparib, in models of triple-negative breast cancer

Background: Selinexor is a SINE (Selective Inhibitor of Nuclear Export) compound currently in Phase I and II clinical trails for the treatment of hematological and solid malignancies. Selinexor blocks the key nuclear export protein XPO1 to force nuclear retention of tumor suppressor proteins (TSPs), including p53, BRCA1/2, pRB and FOXO3A. Olaparib is an FDA approved therapy for BRCA1/2 mutated ovarian cancer, which inhibits Poly-ADP-Ribose Polymerase (PARP) and prevents DNA damage repair. Furthermore, olaparib is being evaluated for the treatment of Triple Negative Breast Cancer (TNBC). We hypothesized that selinexor would restore genomic surveillance through nuclear accumulation of wild type BRCA1 and therefore combination treatment with olaparib would prevent DNA damage repair to amplify cancer cell death.

Methods: The effects of selinexor alone or in combination with olaparib were tested on a panel of 7 TNBC cell lines using MTT and soft-agar colony formation assays in parallel with FACS analysis. In vivo efficacy of single-agent or combination therapy was evaluated using an MDA-MB-468 (BRCA1 wild type, TNBC) xenograft model. Combination index (CI) values were determined using the CompuSyn software and treatment was considered synergistic when CI&lt;1.

Results: The median IC50 values for selinexor and olaparib were 1.88 μM (range: 0.27 μM to &gt;10 μM) and 92.6 μM (range: 17.5 μM to &gt;300 μM), respectively. Combination treatment led to synergistic inhibition of proliferation in the 7 TNBC cell lines evaluated. The median CI tested on the panel of cell lines was 0.68 (ranging from 0.4 to 0.96). FACS analysis revealed an additive effect of the selinexor and olaparib combination on S-phase inhibition and G2 arrest in BRCA1 mutated and wild type cells. Furthermore, AnnexinV/PI staining showed an additive effect on TNBC cell apoptosis regardless of BRCA1 mutational status. In the MDA-MB-468 xenograft model, 75% tumor growth inhibition (TGI) was observed in the combination group by day 22 compared to 55% and 35% TGI for single-agent selinexor and olaparib, respectively.

Conclusion: Selinexor and olaparib in combination act synergistically to induce apoptosis in TNBC cells and amplify anti-tumor effects in a TNBC xenograft model. These data provide a rationale supporting the study of selinexor/olaparib combination in clinical trials.

Citation Format: Helene Marijon, Sigal Gery, Sivan Elloul, Sharon Y. Friedlander, TJ Unger, Robert Carlson, Sharon Shacham, Michael Kauffman, Harold P. Koeffler. Selinexor, a selective inhibitor of nuclear export (SINE) compound, shows enhanced antitumor activity in combination with the PARP inhibitor, olaparib, in models of triple-negative breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-255. doi:10.1158/1538-7445.AM2015-LB-255

"Sub is a weird drug:" A web-based study of lay attitudes about use of buprenorphine to self-treat opioid withdrawal symptoms

BACKGROUND

Illicit use of buprenorphine has increased in the U.S., but our understanding of its use remains limited. This study aims to explore Web-forum discussions about the use of buprenorphine to self-treat opioid withdrawal symptoms.

METHODS

PREDOSE, a novel Semantic Web platform, was used to extract relevant posts from a Web-forum that allows free discussions on illicit drugs. First, we extract information about the total number of buprenorphine-related posts per year between 2005 and 2013. Second, PREDOSE was used to identify all posts that potentially contained discussions about buprenorphine and opioid withdrawal. A total number of 1,217 posts that contained these terms were extracted and entered into NVivo data base. A random sample of 404 (33%) posts was selected and content analyzed.

RESULTS

Buprenorphine-related posts increased over time, peaking in 2011. The posts were about equally divided between those that expressed positive and negative views about the effectiveness of buprenorphine in relieving withdrawal symptoms. Web-forum participants emphasized that buprenorphine's effectiveness may become compromised because of the "size of a person habit," and/or when users repeatedly switch back and forth between buprenorphine and other illicit opioids. Most posts reported use of significantly lower amounts of buprenorphine (≤2 mg) than doses used in standard treatment. Concomitant use of other psychoactive substances was also commonly reported, which may present significant health risks.

CONCLUSIONS

Our findings highlight the usefulness of Web-based data in drug abuse research and add new information about lay beliefs about buprenorphine that may help inform prevention and policy measures.

Effect of selinexor (KPT-330), a novel oral selective inhibitor of nuclear export (SINE), on tumor suppressors and cell cycle proteins in prostate cancer cells and regression of castration-resistant patient-derived xenograft tumor growth

277

Background: Androgen deprivation, anti-androgen and androgen biosynthesis inhibitor treatment can initially control the metastatic prostate cancer (PCa), but treatment-refractory progression frequently follows, with the loss of tumor suppressors (TSPs) and increased expression of cell cycle proteins. Inhibition of the nuclear export protein, Exportin 1 (XPO1) leads to nuclear accumulation of cargo proteins such as TSPs & cell-cycle regulators implicated in castration-resistant PCa (CRPC) progression. XPO1 and specific cargo genes are overexpressed in metastatic CRPC relative to benign & primary prostate tumors, implicating XPO1 activity as playing a role in disease progression. Selinexor (KPT-330), a novel, oral SINE currently in Phase 1/2 for both hematological and solid tumors, has potent activity against CRPC. We hypothesized this activity is due selinexor induced nuclear expression of TSPs. Methods: To test this hypothesis, we treated selected PCa cell lines and patient-derived xenografts (PDXs, two adenocarcinomas and one small cell carcinonoma) with selinexor to determine the effect on survival and cargo protein localization. Results: Treatment with selinexor markedly inhibited PCa cell proliferation in vitro, activated the tumor suppressor TP53 & inhibited cell-cycle regulators. Also, treatment of the PDXs with selinexor for at least 3 weeks significantly inhibited tumor growth & reduced the prostate-specific antigen level in the adenocarcinomas. Selinexor increased cell death in all three PDX tumors and reduced cell proliferation in the adenocarcinomas, but not in the small-cell tumor. Expression analyses demonstrated that selinexor induced nuclear accumulation of different cargo proteins unique to the PCa model, accounting for PDX-specific regression. Conclusions: These results point to an anti-tumorigenic effect of selinexor treatment across a spectrum of hormone-refractory PCa that may provide insight into the drivers of PCa treatment resistance and heterogeneity.

Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.