Focal adhesion kinase-YAP signaling axis drives drug-tolerant persister cells and residual disease in lung cancer

Targeted therapy is effective in many tumor types including lung cancer, the leading cause of cancer mortality. Paradigm defining examples are targeted therapies directed against non-small cell lung cancer (NSCLC) subtypes with oncogenic alterations in EGFR, ALK and KRAS. The success of targeted therapy is limited by drug-tolerant persister cells (DTPs) which withstand and adapt to treatment and comprise the residual disease state that is typical during treatment with clinical targeted therapies. Here, we integrate studies in patient-derived and immunocompetent lung cancer models and clinical specimens obtained from patients on targeted therapy to uncover a focal adhesion kinase (FAK)-YAP signaling axis that promotes residual disease during oncogenic EGFR-, ALK-, and KRAS-targeted therapies. FAK-YAP signaling inhibition combined with the primary targeted therapy suppressed residual drug-tolerant cells and enhanced tumor responses. This study unveils a FAK-YAP signaling module that promotes residual disease in lung cancer and mechanism-based therapeutic strategies to improve tumor response.

Low temperature Raman spectroscopic study of anharmonic and spin-phonon coupled quasi-two dimensional rare earth based francisites

Mineral francisites Cu3Bi(SeO3)2O2Cl are unique compounds with interesting quasi two-dimensional structure along with fascinating magnetic properties. The magnetic properties can be fine-tuned when non-magnetic Bi is replaced by a suitable rare earth (RE) metal. It is because of the inclusion of additional magnetic sub-centre RE apart from Cu. Temperature dependent Raman spectroscopy measurements in RE based francisites [Cu3RE(SeO3)2O2Cl, shortly RECufr] were performed in the range of 11 K-295 K. Among the three studied RECufr (LaCufr, NdCufr, and DyCufr) compounds, the properties of phonon vibration vary from moderate (in DyCufr) to weak (in LaCufr) spin phonon coupled and the absence of spin phonon coupling (SPC) (i.e. strictly anharmonic in nature) was observed in NdCufr and the reason for this observation has been provided. More specifically, two Raman-active phonons soften below the antiferromagnetic ordering temperature ofTN≈ 39 K in DyCufr compound, indicating the existence of moderate SPC. This trend of phonon vibration is correlated with magnetic properties, particularly field induced metamagnetic transition (MMT). Strong MMT enabled DyCufr develops SPC, while weak MMT enabled NdCufr is unable to develop SPC.

An inflamed tumor cell subpopulation promotes chemotherapy resistance in triple negative breast cancer

Individual cancers are composed of heterogeneous tumor cells with distinct phenotypes and genotypes, with triple negative breast cancers (TNBC) demonstrating the most heterogeneity among breast cancer types. Variability in transcriptional phenotypes could meaningfully limit the efficacy of monotherapies and fuel drug resistance, although to an unknown extent. To determine if transcriptional differences between tumor cells lead to differential drug responses we performed single cell RNA-seq on cell line and PDX models of breast cancer revealing cell subpopulations in states associated with resistance to standard-of-care therapies. We found that TNBC models contained a subpopulation in an inflamed cellular state, often also present in human breast cancer samples. Inflamed cells display evidence of heightened cGAS/STING signaling which we demonstrate is sufficient to cause tumor cell resistance to chemotherapy. Accordingly, inflamed cells were enriched in human tumors taken after neoadjuvant chemotherapy and associated with early recurrence, highlighting the potential for diverse tumor cell states to promote drug resistance.

Highly correlated structural, local structural, Raman spectroscopic and magnetic properties of Mn-substituted Cu2V2O7

Low-dimensional quantum spin ½ system Cu2V2O7has been investigated in the framework of Mn-substitution at the Cu site, which is really un-investigated. The studied compounds Cu2 -xMnxV2O7(x= 0, 0.05, 0.1 and 0.15) have been synthesized and characterized structurally, spectroscopically, local structurally and magnetically via x-ray diffraction, Raman, x-ray absorption and temperature, field dependent magnetization measurements respectively. Although Cu2V2O7can be found inα, βandγ-phase, however all of the studied compounds are found in single orthorhombicα-phase which has crucial magneto-electric application potential. Temperature dependent Raman spectra indicated anharmonic phonon-phonon scattering but there is no spin-phonon coupling for VO4vibrational modes. The local structure probed via x-ray absorption near edge structure and extended x-ray absorption fine structure spectroscopy at 15 K, 300 K indicates Cu2+, V5+and mixed valent Mn2+and Mn3+ionic states and justified local structure for the probed ions. Magnetic measurements indicate long-range antiferromagnetic ordering with doping independent Neel temperature (32.5 K). Further observations are strong magnetic hysteresis at 5 K (due to canted spin structure), zero field exchange-bias and their noteworthy enhancement upon Mn-substitution. Interesting correlation between structural parameters and magnetic exchanges has been developed.

Computational drug repositioning for the identification of new agents to sensitize drug-resistant breast tumors across treatments and receptor subtypes

Introduction

Drug resistance is a major obstacle in cancer treatment and can involve a variety of different factors. Identifying effective therapies for drug resistant tumors is integral for improving patient outcomes.

Methods

In this study, we applied a computational drug repositioning approach to identify potential agents to sensitize primary drug resistant breast cancers. We extracted drug resistance profiles from the I-SPY 2 TRIAL, a neoadjuvant trial for early stage breast cancer, by comparing gene expression profiles of responder and non-responder patients stratified into treatments within HR/HER2 receptor subtypes, yielding 17 treatment-subtype pairs. We then used a rank-based pattern-matching strategy to identify compounds in the Connectivity Map, a database of cell line derived drug perturbation profiles, that can reverse these signatures in a breast cancer cell line. We hypothesize that reversing these drug resistance signatures will sensitize tumors to treatment and prolong survival.

Results

We found that few individual genes are shared among the drug resistance profiles of different agents. At the pathway level, however, we found enrichment of immune pathways in the responders in 8 treatments within the HR+HER2+, HR+HER2-, and HR-HER2- receptor subtypes. We also found enrichment of estrogen response pathways in the non-responders in 10 treatments primarily within the hormone receptor positive subtypes. Although most of our drug predictions are unique to treatment arms and receptor subtypes, our drug repositioning pipeline identified the estrogen receptor antagonist fulvestrant as a compound that can potentially reverse resistance across 13/17 of the treatments and receptor subtypes including HR+ and triple negative. While fulvestrant showed limited efficacy when tested in a panel of 5 paclitaxel resistant breast cancer cell lines, it did increase drug response in combination with paclitaxel in HCC-1937, a triple negative breast cancer cell line.

Conclusion

We applied a computational drug repurposing approach to identify potential agents to sensitize drug resistant breast cancers in the I-SPY 2 TRIAL. We identified fulvestrant as a potential drug hit and showed that it increased response in a paclitaxel-resistant triple negative breast cancer cell line, HCC-1937, when treated in combination with paclitaxel.

A bi-steric mTORC1-selective inhibitor overcomes drug resistance in breast cancer

Activation of the PI3K-mTOR pathway is central to breast cancer pathogenesis including resistance to many targeted therapies. The mTOR kinase forms two distinct complexes, mTORC1 and mTORC2, and understanding which is required for the survival of malignant cells has been limited by tools to selectively and completely impair either subcomplex. To address this, we used RMC-6272, a bi-steric molecule with a rapamycin-like moiety linked to an mTOR active-site inhibitor that displays >25-fold selectivity for mTORC1 over mTORC2 substrates. Complete suppression of mTORC1 by RMC-6272 causes apoptosis in ER+/HER2- breast cancer cell lines, particularly in those that harbor mutations in PIK3CA or PTEN, due to inhibition of the rapamycin resistant, mTORC1 substrate 4EBP1 and reduction of the pro-survival protein MCL1. RMC-6272 reduced translation of ribosomal mRNAs, MYC target genes, and components of the CDK4/6 pathway, suggesting enhanced impairment of oncogenic pathways compared to the partial mTORC1 inhibitor everolimus. RMC-6272 maintained efficacy in hormone therapy-resistant acquired cell lines and patient-derived xenografts (PDX), showed increased efficacy in CDK4/6 inhibitor treated acquired resistant cell lines versus their parental counterparts, and was efficacious in a PDX from a patient experiencing resistance to CDK4/6 inhibition. Bi-steric mTORC1-selective inhibition may be effective in overcoming multiple forms of therapy-resistance in ER+ breast cancers.

P-116 UNUSUAL VISCERAL CONTENT IN PARASTOMAL HERNIAS - A REVIEW OF LITERATURE

Parastomal hernias remain the most common complication of an ileostomy or colostomy - It is estimated that upto 50 percent of patients with a stoma will develop one. They may be classified as Interstitial, Subcutaneous, Intrastomal or Peristomal. The most common contents of Parastomal Hernias are bowel and omentum.However, other visceras have been reported as a content of a parastomal hernia. This presentation is aimed at a literature review of such surprise surgical situations that are challenging to the surgeons.

Presence of gallbladder in a parastomal hernia has been reported by multiple authors - there is reported incidence of incarceration or acute inflammation of the gallbladder. Cholecystectomy t the time of parastomal hernia repair has been reported though some patients have been treated non-operatively as well.

Similarly, there have been multiple reports of stomach beong the contents of parastomal hernias - there have been patients presenting with gastric outlet obstruction who have been found to have the stomach being a content of their parastomal herniation.

This presentation reviews the available literature and presents the challenges and oprions that a surgeon may face when treating similar patients.

P-115 HYBRID REPAIR OF RECURRENT COMPLEX GROIN HERNIA - CHALLENGES AND LESSONS LEARNT

A 45 year old lady presented with a recurrent swelling over the right groin that had gradually turned tense and tender over the last 48 hours. Having undergone an urgent right femoral hernia repair in 2002, she underwent an inguinal hernioplasty in 2004 and amesh repair of a recurrent inguinal hernia in 2008. She developed a third recurrence that slowly increased in size and needed an urgent repair. At assessment, she was found to have a large complete recurrent irreducible right inguinal hernia containing loops of bowel.

At laparoscopy, multiple loops of bowel and omentum were reduced from a large multiloculated hernial sac. In view of the large sac which had incorporated the previously placed meshes in the wall, a decision was made to abandon laparoscopic approach. The myopectineal orifice was approached through a groin incision and the hernial sac with it's locules, including a prevascular component, was defined. The posterior sheath was defined and the rigt rectus muscle, displaced by the hernia, was repositioned. The dissection was carried upto the Space of Bogros to ensure that no component of the hernia was missed out. After completing a formal herniotomy, a sandwich prosthesis, created by stitching a biomesh and a polypropylene mesh, was utilised for hernia repair.

The patient had an uneventful recovery.

The presentation is aimed at discussing the challenges of repairing a complex recurrent hernia, the possible pitfalls and lessons learnt.

Abstract PO017: HBV alters YAP regulation in liver cancer by remodeling PP2A complexes

Viral hepatitis promotes hepatocellular carcinoma (HCC) initiation by inducing inflammation, cellular stress and cell death. However, the cell-intrinsic effects of viral infection in advanced HCC remain unclear. We used affinity purification mass spectrometry to develop a complete map of 145 interactions among Hepatitis B Virus (HBV) and host proteins in the HUH7 HCC tumor cell line, identifying known and novel HBV/host protein-protein interactions. We integrated this map with HCC genomes, identifying 61 proteins with preferential mutation in non-HBV HCC, suggesting that their interaction with HBV plays a role in cancer. Focusing on proteins that directly interact with the HBV oncoprotein X (HBx), we found that HBx rewires the effect of the PP2A phosphatase on HCC signaling. HBx binding excluded striatin-family regulatory subunits from the PP2A complex, causing Hippo kinase activation. This effect creates a requirement for integrin signaling to mTOR complex 2 to maintain expression of the YAP oncoprotein, critical for HCC growth. Thus, HBV rewires HCC signaling and may promote targetable dependencies.

Citation Format: John Gordan, Adriana Pitea, Rigney E Turnham, Manon Eckhardt, Gwendolyn M Jang, Huat Lim, Alex L Choi, Sourav Bandyopadhyay, Danielle Swaney, Kevan Shokat, Trey Ideker, Nevan Krogan. HBV alters YAP regulation in liver cancer by remodeling PP2A complexes [abstract]. In: Proceedings of the AACR Special Conference: Advances in the Pathogenesis and Molecular Therapies of Liver Cancer; 2022 May 5-8; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(17_Suppl):Abstract nr PO017.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Prevalence and molecular characterization of extended-spectrum β-lactamase (ESBL) producing Escherichia coli isolated from dogs suffering from diarrhea in and around Kolkata

BACKGROUND

Dogs are the favorite companion animals among humans. The close interaction between dogs and people increases the risk of antibiotic resistance spreading. Surveillance for antimicrobial resistance and the identification of ESBL-producing Escherichia coli as an indicator bacterium is an important tool for managing antimicrobial drug therapy.

AIMS

The present study targeted to identify and characterize ESBL-producing E. coli among dogs suffering from diarrhea in and around Kolkata.

METHODS

Isolation and identification of E. coli from dogs suffering from diarrhea (n=70) along with screening for the production of both ESBL and AmpC. The isolates were further characterized through antimicrobial resistance profiling, resistance genes (bla _CTX-M, bla _TEM, and bla _SHV) screening, and phylogenetic group study.

RESULTS

Among the 70 isolates, 21 (30%) were confirmed ESBL producers. An antibiogram typing of ESBL-producing E. coli revealed that the majority of them were resistant to norfloxacin (85.7%) followed by tetracycline (61.90%), doxycycline (57.14%), piperacillin/tazobactam (52.38%), cotrimoxazole (47.62%), gentamicin (42.62%), amikacin (23.81%), and chloramphenicol (19.05%). Major resistance genes included bla _CTX-M (100%), bla _TEM (28.57%), and bla _SHV (9.50%). The predominant phylogenetic groups were phylogroup A (76%) followed by phylogroup D (24%).

CONCLUSION

The current investigation reported a high prevalence of both ESBL and AmpC β-lactamase (AmpC) producing E. coli, co-resistance to a distinct group of antibiotics, and co-existence of different ESBL genes in dogs. Our findings highlight the importance of diagnostic antimicrobial susceptibility testing for proper antimicrobial therapy and to prevent antimicrobial resistance from spreading to humans from dogs in Kolkata and the surrounding area.

Absence of clinical benefit of FDG PET-CT in staging T1 part-solid lung adenocarcinoma

AIM

To assess the rates of nodal and metastatic disease and change in management when staging part-solid T1 lung adenocarcinomas using integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)-computed tomography (CT) in a UK population.

MATERIALS AND METHODS

This was a retrospective review of PET-CT examinations performed to stage radiologically suspected T1 part-solid lung adenocarcinoma (n=58) from two different centres. Rates of detection of nodal and metastatic disease, change in management, and final patient outcome were recorded.

RESULTS

PET-CT changed the stage in one patient from N0 to N1. It did not change final management in any patient.

CONCLUSIONS

In this UK population, PET-CT had minimal additional diagnostic benefit in staging patients with T1 part-solid lung adenocarcinoma. Especially given its cost, the inclusion of PET-CT for this indication in guidelines should be reviewed.

Effect of Co and Mg doping at Cu site on structural, magnetic and dielectric properties of α-Cu2V2O7

We have studied the effect of doping of both magnetic (Co) and nonmagnetic (Mg) ions at the Cu site on phase transition in polycrystalline α-Cu₂V₂O₇through structural, magnetic, and electrical measurements. X-ray diffraction reveals that Mg doping triggers an onset ofα- toβ-phase structural transition in Cu_2-xMg_xV₂O₇above a critical Mg concentrationx_c= 0.15, and both the phases coexist up tox= 0.25. Cu₂V₂O₇possesses a non-centrosymmetric crystal structure and antiferromagnetic ordering along with a non-collinear spin structure in theαphase, originated from the microscopic Dzyaloshinskii-Moriya interaction between the neighboring Cu spins. Accordingly, a weak ferromagnetic (FM) behavior has been observed up tox= 0.25. However, beyond this concentration, Cu_2-xMg_xV₂O₇exhibits complex magnetic properties. A clear dielectric anomaly is observed in α-Cu_2-xMg_xV₂O₇around the magnetic transition temperature, which loses its prominence with the increase in Mg doping. The analysis of experimental data shows that the magnetoelectric coupling is nonlinear, which is in agreement with the Landau theory of continuous phase transitions. Co doping, on the other hand, initiates a sharpαtoβphase transition around the same critical concentrationx_c= 0.15 in Cu_2-xCo_xV₂O₇but the FM behavior is very weak and can be detected only up tox= 0.10. We have drawn the magnetic phase diagram which indicates that the rate of suppression in transition temperature is the same for both types of doping, magnetic (Co) and nonmagnetic (Zn/Mg).

22 Motivations, Barriers, And Social Media: A Qualitative Study of Uptake of Women into Neurosurgery

Objective

To explore how social media could be utilised to influence an individual’s motivation to pursue a neurosurgical career, an emerging topic area. The focus of this study was on women interested in neurosurgery.

Background

Women are significantly under-represented in neurosurgery. 18% of all neurosurgeons – including 8% of consultants – are women. Most previous studies have used quantitative methods that are not best suited to gaining an in-depth understanding of the barriers that women face in pursuing a career in neurosurgery, or what would enable more women to go into the speciality.

Method

In this qualitative study, individual semi-structured interviews were conducted until data saturation was achieved. Participants were women pre-neurosurgical trainees. The interview data was examined through a thematic analysis involving open and axial coding.

Results

Thirty women participated in the study. Four overarching themes were identified: (1) mentorship, (2) testimony from other women doing neurosurgery, (3) social media as a means of increasing interest in neurosurgery as a career choice, and (4) real-life exposure to the speciality.

Conclusions

There is scope to further improve uptake of women into neurosurgical training in the UK. Motivations and barriers to women pursuing neurosurgery should be addressed openly through early experience, role models and mentorship. Social media can help facilitate these opportunities, disseminate information and inspiration, and has the potential to undo societal biases.

476 The Role of Medical Students in an International, Collaborative, Multi-Centre Global Surgery Study

Introduction

The gaps in formal education caused by the pandemic have provided medical students with opportunities to redefine their role in settings across clinical medicine, education and research. This task shifting could provide avenues for students to engage with global surgery, where the cultivation of research skills, networking, and global collaboration amongst students is imperative for sustainable progress.

COVIDPaedsCancer is an international collaborative cohort study assessing the impact of the pandemic on paediatric cancer services. We aimed to trial a student and junior doctor-lead team to perform the day-to-day running of this research.

Method

An operations team of 47 students and junior doctors across 11 countries was assembled. Sub-teams were created for social media, network management, email communications, REDCap, research support and graphics. Together, they ran the study under guidance from the steering committee.

Results

To date, the operations team has coordinated study collaborators in collecting data for 1252 patients from 78 centres across 39 countries. Cooperation between sub-teams enabled the recruitment of collaborators from 558 hospitals in total. They also identified 2 errors in the protocol and resolved them with steering committee input, and continuously managed hospital leadership issues and general queries throughout the course of the study. The team was able to adapt in response to the evolving needs of collaborators and the steering committee.

Conclusions

Medical students were able to aid the delivery of an international, multicentre, collaborative, global surgery research study while benefiting from learning opportunities, networking opportunities, and developing interest and understanding of global surgery.

244 Traumatic Brain Injury Related Paediatric Mortality and Morbidity in Low- And Middle-Income Countries: A Systematic Review and Meta-Analysis

Aim

Three million cases of paediatric traumatic brain injury (pTBI) occur annually, the majority of which occur in low-and-middle-income countries (LMICs). However, there is a paucity of data on the outcomes of pTBI available. We aimed to systematically review and synthesise the reported morbidity and mortality from pTBI in the published literature about LMICs.

Method

A systematic review and meta-analysis were conducted. MEDLINE, EMBASE, Global Health, and Global Index Medicus were searched for relevant articles from January 2000 to May 2020. Observational or experimental studies on pTBI (individuals between the ages of 0 to 16 years) in LMICs were included. Morbidity data were descriptively analysed, and a random-effects model was used to pool mortality rates. PROSPERO ID: CRD42020171276.

Results

We included 145 studies from 38 countries representing 174073 patients with pTBI. Males were twice (95% CI: 1.6 – 2.4) as likely to have a pTBI than females. Where available, mild TBI represented ≥ 60% of all pTBI cases in most reports (n = 24/43, 56%). The commonest cited cause of pTBI was road traffic accidents (n = 16643/43083, 39%), followed by falls (n = 10927/43083, 25%). 4385 patients (n = 4385/18092, 24%) had a reduction from normal function on discharge. On average, there were 6.7 deaths per 100 cases of pTBI.

Conclusions

Only 38 LMICs have published data on the volume and burden of pTBI in their country. Limited data available suggests that young male children are at a high-risk of pTBIs in LMICs, particularly from road traffic accidents.

AB0223 MODIFIED DOSE RITUXIMAB BIOSIMILAR IN RHEUMATOID ARTHRITIS COMPARING B-CELL DEPLETION EFFECT AND DISEASE ACTIVITY SCORES

Background:

In emerging economies self-funding patients opt for less costly options, influencing both compliance and maintenance of treatment for chronic illness. Studies comparing originator rituximab 1000mgx2 and 500mgx2 doses in Rheumatoid arthritis (RA) have yielded interesting results1. Evidence of B cell depletion, measured by CD19 count, maybe a marker for disease improvement2. However effect of different dose of biosimilar Rituximab (bRTX) on B cell depletion and disease activity needs exploration.

Objectives:

To determine correlation of CD19 count defining B cell depletion and disease activity with different dosages of bRTX treatment.

Methods:

Between April 2019 and March 2020, all RA patients with DMARD failure were screened for eligibility of biologics as routine clinical practice. Depending on individual choice, after full consent, patients received either 1000mgx2 or 500mgx2 bRTX. All patients had CD19 count before and 12 months after the first dose. Effectiveness of bRTX 1000 mg×2 and 500 mg×2 was assessed by DAS28 and EULAR response. Comparative adjusted analysis was performed by analysis of variance (ANOVA).

Results:

Out of 468 eligible patient, 84 opted for biologic. Of which 27 patients consented for bRTX (17 female, mean age 39.5 years).13 patients opted for 1000mg×2 and 14 for 500mg×2 dose. 74% (20/27) patients were on concomitant methotrexate and 26% on hydroxychloroquine (7/27). Both doses led to significant reduction in ESR, CRP, and DAS28-ESR at 12 months (p<0.001) (Table 1).

Table 1.

RA outcome-measurement scores at 12 months post biosimilar Rituximab therapy.

VariableBaseline12 monthsRTX 1000mg x 2(n=13)RTX 500mg x 2(n=14)RTX 1000mg x 2(n=13)RTX 500mg x 2(n=14)ESR*53.9±23.957.1±24.723.9±2.924.1±4.7CRP*6.1±3.96.9±2.92.1±0.92.3±0.9DAS28-ESR*6.1±0.36.1±0.24.0±0.44.1±0.2CD 19+ Count*# (105/L)1191.6±308.41155±289.6128.8±90.4139±90.6

* p<0.0001 as compared to 12 mos vs baseline; # p<0.0001 as compared amongst group

At the end of 12 months, compared to 1000mg, CD19 count was higher in 500mg group (p=0.25). Percentage of patients achieving EULAR moderate or no response was higher in 500mg group (37%vs29%, p=0.205), both complete and incomplete B cell depletion, but patients achieving good response was same in both groups (14.8%vs18.5%, p = 0.25). (Figure 1).

Figure 1.

EULAR Response at 12 months

Conclusion:

Low dose bRTX is effective in DMARD refractory RA patients with similar improvements as regular dose, although CD19 depletion was less in low dose group. A larger study to establish radiographic regression with CD19 depletion and disease activity score can help in further strengthening the use of lower dose bRTX in RA leading to significant economic advantage.

References:

[1]Chatzidionysiou K, Lie E, Nasonov E, Lukina G,et al. Rheumatic Diseases Portuguese Register. Effectiveness of two different doses of rituximab for the treatment of rheumatoid arthritis in an international cohort: data from the CERERRA collaboration. Arthritis Res Ther. 2016 Feb 16;18:50.

[2]Vital EM, Rawstron AC, Dass S, Henshaw K, Madden J, Emery P, McGonagle D. Reduced-dose rituximab in rheumatoid arthritis: efficacy depends on degree of B cell depletion. Arthritis Rheum. 2011 Mar;63(3):603-8.

Disclosure of Interests:

None declared

Phase I study of the aurora kinase A inhibitor alisertib in combination with osimertinib in EGFR-mutant lung cancer

9074

Background: The 3rd generation EGFR tyrosine kinase inhibitor (TKI) osimertinib is effective for the treatment of advanced EGFR-mutant (mt) lung adenocarcinoma (LUAD). However, tumor resistance to osimertinib monotherapy invariably occurs. Activation of Aurora Kinase A (AURKA) drives resistance to osimertinib treatment in preclinical models of EGFR-mutant LUAD and is associated with TKI resistance in patients. Alisertib is a selective AURKA inhibitor with an acceptable safety profile established in early phase clinical trials. Methods: We performed a single institution phase Ia clinical trial of alisertib in combination with the 3rd generation EGFR inhibitor osimertinib in patients with metastatic EGFR-mutant LUAD who had experienced disease progression on osimertinib monotherapy (NCT04085315). The primary objective of the study was to determine the safety and tolerability of alisertib in combination with osimertinib in order to define the maximum tolerated dose (MTD) and to identify a recommended phase 2 dose (RP2D). Secondary efficacy endpoints included objective response rate (ORR), disease control rate (DCR) and progression-free survival (PFS). Utilizing a 3+3 trial design, patients receiving osimertinib 80 mg daily were treated with alisertib using an intermittent dosing strategy of 20-50 mg twice daily (BID) oral alisertib on days (d) 1-3, 8-11, and 15-17 of a 28-day cycle. Results: A total of 10 patients were treated with osimertinib 80 mg and received at least one dose of alisertib. 6 patients were treated at the 30 mg BID and 4 patients at the 40 mg BID intermittent dosing schedule of alisertib. The most commonly reported adverse events (AEs) were diarrhea (70%), fatigue (60%), alopecia (50%) and neutropenia (50%). All AEs, except neutropenia, were grade 1 or 2. Two patients (20%) experienced grade 3 or grade 4 neutropenia; both patients were treated at the 40 mg BID intermittent dose of alisertib. Intermittent alisertib 30 mg BID was identified as the MTD and RP2D in combination with osimertinib 80 mg daily. The ORR was 10% (1/10) and DCR 70% (7/10), with the majority of patients, 60% (6/10), achieving stable disease (SD). 30% (3/10) experienced progressive disease (PD) as their best response. The median PFS was 9.4 months (2.0 months - N.R.). Conclusions: Intermittent dosing of alisertib 30 mg BID on d1-3, 8-11, and 15-17 of a 28-day cycle in combination with osimertinib 80 mg daily demonstrates an acceptable toxicity profile. Preliminary efficacy analysis suggests that alisertib + osimertinib may result in clinically meaningful disease control in EGFR-mt LUAD patients whose disease is resistant to osimertinib monotherapy. Clinical trial information: NCT04085315.

721 Imaging for Suspected Bowel Obstruction in Pennine Acute Trust (PAT): A Comparison with the National Audit of Small Bowel Obstruction’s (NASBO) recommendations

Background

NASBO recommends Computed Topography (CT) over plain abdominal X-ray (AXR) for the investigation of bowel obstruction (BO). AXR is routinely used within PAT for investigation of BO which may be exposing patients to unnecessary radiation and adding unnecessary cost to the service.

Method

A retrospective audit collected data on patients with CT confirmed BO between July 2019 and February 2020. This looked at the percentage of patients who had both CT and AXR to investigate BO. The cost of these AXRs and the percentage of these AXRs that were normal were also calculated.

Results

A search identified 141 patients with CT proven BO. 81/141(57.4%) patients had both AXR and CT as a part of their initial investigations. Of those patients 26/81(32.1%) had no AXR features suggestive of BO. Only 12/81(14.8%) of those patients had serial AXRs following initial imaging. The cost for one AXR is £34.15 which means £2766.15 was spent on potentially unnecessary AXRs within this period.

Conclusions

PAT is performing potentially unnecessary AXRs which is exposing patients to unnecessary radiation and costing the trust. Plain AXRs do not rule out BO. We have recommended an investigation flowchart to PAT A&E departments to reduce unnecessary AXRs being performed.

77 The Development of Core Outcome Sets and Common Data Elements in Clinical Neurosciences: A Scoping Review

Introduction

The use of core outcome sets (COS) and common data elements (CDEs) minimises research wastage by increasing the cross-comparison and meta-analysis of study findings. Our study sought to identify the clinical neuroscience subspecialties that have developed COS and CDEs, the countries of origin of authors, and the process through which COS and CDEs were developed.

Method

A search between 2000-2020 of the top 40 Impact Factor neurosurgical and neurological journals was conducted. A scoping review was performed in accordance with the PRISMA-ScR Checklist.

Results

Our search returned 169 papers, of which 35 were eligible for inclusion. The USA published the majority of papers (20/35). The papers mostly related to neurosurgery (30/35), with the most common neurosurgical sub-specialty being traumatic brain injury (14/35). There is an increasing publication trend over time, with 12 papers published in 2019. Five papers were systematic reviews conducting with the intention of COS/CDE development. 27 papers reported CDE development and 2 papers reported COS development. The COS development papers utilised international consensus meetings and adhered to international development statements.

Conclusions

COS and CDEs are increasingly being developed within clinical neurosciences. There is a need for greater international collaboration with regards to COS and CDEs development.

13 Medical Students’ Mood Adversely Affected By COVID-19 Pandemic: An Interim Analysis from the SPICE-19 Prospective Cohort Study Of 2075 Medical Students and Interim Foundation Doctors

Introduction

In order to appropriately support medical students and foundation year doctors, it is imperative that we understand the impact the COVID-19 pandemic has had upon them. This study assessed the effects of the COVID-19 pandemic on medical students and interim foundation year doctors across the United Kingdom (UK), and the support that they received and sought.

Method

A prospective, observational, multicentre study was conducted. All medical students and interim foundation year doctors were eligible to participate.

Results

A total of 2075 individuals participated. There was a decrease in participants’ mood when comparing their mood before the pandemic to during the pandemic (p < 0.0001). Social distancing negatively impacted the mood of the greatest number of participants. All areas of life included in the study were found to have been significantly more negatively impacted than positively impacted (p < 0.0001). 931 participants wanted more support from their university.

Conclusions

When medical students return to their universities, there is likely to be a need for enhanced wellbeing support, adaptations in the short-term and long-term strategies for medical education, and provision of financial guidance. If no action is taken, there may be a knock-on effect on workforce planning and the health of our future workforce.

Metal contaminations in sediment and associated ecological risk assessment of river Mahanadi, India

Mahanadi is one of the major rivers of peninsular India. Like other Indian rivers, it is contaminated with sewages, industrial discharges, and agricultural runoff. Thus, necessity was felt to monitor its pollution status. Present work was part of that program and aimed to assess the sediment contamination due to the trace metals Cd, Cr, Cu, Mn, Pb, and Zn during 2012-2015. Sediment pollution status and ecological risks were evaluated calculating contamination factor (CF), geo-accumulation (I_geo), pollution load index (PLI), potential ecological risk (EⁱR), etc. The recorded metal concentrations were Cd BDL of flame mode of AAS; Cr BDL - 73.9; Cu BDL - 44.4; Mn 37.2 - 1887.0; Pb BDL - 29.5; and Zn BDL - 92.5 mg kg^-1. As per US EPA guidelines, Cr concentrations at many locations were in the moderately polluted range. I_geo, CF, mC_d, PLI, and EⁱR indicated low pollution levels and low ecological risks due to the trace metals assessed. The sediment quality guidelines (SQGs) indicated that Cr and Cu concentrations exceeded (16% sample) the threshold effect concentrations and may occasionally exhibit adverse biological effects. The association of sediment organic matter, conductivity and content of Cu, and their grouping in component 1 of PCA revealed that the anthropogenic input was dominant and so also the component 2 where Cr exhibited moderately good correlation with organic matter. Cluster analysis of the sampling sites based on pollution status yielded 3 groups: relatively uncontaminated (S3, S4), low to moderately contaminated (S2), and moderately contaminated (S1, S5, S6) stretches.

Multi-drug resistant, biofilm-producing high-risk clonal lineage of Klebsiella in companion and household animals

Antimicrobial resistance is a global emergency which needs one health approach to address. The present study was conducted to detect the prevalence of beta-lactamase and biofilm-producing Klebsiella strains in rectal swabs (n = 624) collected from healthy dogs, cats, sheep and goats reared as companion or household animals in India. The dogs and cats were frequently exposed to third- or fourth-generation cephalosporins for therapy. The sheep and goats were occasionally exposed to antibiotics and had environmental exposure. Phenotypical ESBL (n = 93) and ACBL (n = 88)-producing Klebsiella were isolated significantly more (P < 0·05) from companion animals than household animals. Majority of the Klebsiella possessed bla_CTX-M-15 . The sequences bla_CTX-M-15.2 , bla_CTX-M-197 and bla_CTX-M-225 are reported first time from the companion animals. All ACBL-producing isolates possessed bla_AmpC . The present study detected 65·8% of Klebsiella strains as biofilm producers possessing the studied biofilm associated genes. The isolates showed phenotypical resistance against chloramphenicol, tetracycline, doxycycline, co-trimoxazole, ampicillin, cefotaxime/clavulanic acid. The present study showed that companion and household animals (dogs, cats, sheep, goats) may act as a carrier of ESBL/biofilm-producing, multi-drug resistant, high-risk clonal lineage of Klebsiella.

Nf1-Mutant Tumors Undergo Transcriptome and Kinome Remodeling after Inhibition of either mTOR or MEK

Loss of the tumor suppressor NF1 leads to activation of RAS effector pathways, which are therapeutically targeted by inhibition of mTOR (mTORi) or MEK (MEKi). However, therapeutic inhibition of RAS effectors leads to the development of drug resistance and ultimately disease progression. To investigate molecular signatures in the context of NF1 loss and subsequent acquired drug resistance, we analyzed the exomes, transcriptomes, and kinomes of Nf1-mutant mouse tumor cell lines and derivatives of these lines that acquired resistance to either MEKi or mTORi. Biochemical comparisons of this unique panel of tumor cells, all of which arose in Nf1^+/- mice, indicate that loss of heterozygosity of Nf1 as an initial genetic event does not confer a common biochemical signature or response to kinase inhibition. Although acquired drug resistance by Nf1-mutant tumor cells was accompanied by altered kinomes and irreversibly altered transcriptomes, functionally in multiple Nf1-mutant tumor cell lines, MEKi resistance was a stable phenotype, in contrast to mTORi resistance, which was reversible. Collectively, these findings demonstrate that Nf1-mutant tumors represent a heterogeneous group biochemically and undergo broader remodeling of kinome activity and gene expression in response to targeted kinase inhibition.

Abstract 1470: UGP2 is a critical regulator of protein glycosylation in pancreatic cancer

UDP-glucose pyrophosphorylase 2 (UGP2) is a lynchpin metabolic enzyme that rests at the convergence of multiple metabolic pathways regulating both glycogen synthesis and glycosylation modifications. Here we elucidated the essential role of UGP2-mediated glycosylation in the maintenance of KRAS-driven cancer using both in vitro and in vivo models. A key effector of KRAS oncogenic function is the transcription factor YAP. We identified the YAP/TEAD transcription factor complex as a major regulator of UGP2 mRNA expression and enzymatic activity using genomic perturbations, correlative protein immunohistochemistry in PDAC samples, and ChIP-seq and targeted ChIP-qPCR at the UGP2 promoter. Loss of YAP or UGP2 leads to a decrease in glycogen and defects in key glycosylation targets such as EGFR. In murine xenograft models using pancreatic cancer lines, knockdown of UGP2 prevented tumor growth and decreased expression of the critical glycosylation target EGFR. This essential role for UGP2 in cancer maintenance may lead to new avenues of therapy in otherwise intractable KRAS-driven cancers.

Citation Format: Andrew L. Wolfe, Jacqueline Galeas, Eneda Toska, Qing Zhou, Angel Ku, Richard P. Koche, Sourav Bandyopadhyay, Carlito B. Lebrilla, Maurizio Scaltriti, Frank McCormick, Sung Eun Kim. UGP2 is a critical regulator of protein glycosylation in pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1470.

Cutaneous T-Cell Lymphoma PDX Drug Screening Platform Identifies Cooperation between Inhibitions of PI3Kα/δ and HDAC

Cutaneous T-cell lymphoma is a form of non-Hodgkin lymphoma that manifests initially in the skin and disseminates systemically as the disease progresses. Mycosis fungoides and Sézary syndrome are the most common subtypes of cutaneous T-cell lymphoma. Advanced mycosis fungoides and Sézary syndrome are life threatening with few treatment options. We searched for new agents by high-throughput screening of selected targeted compounds and identified high-value targets, including phosphatidylinositol 3-kinase (PI3K) and cyclin-dependent kinases. To validate these hits from the screen, we developed patient-derived xenograft mouse models that recapitulated the cardinal features of mycosis fungoides and Sézary syndrome and maintained histologic and molecular characteristics of their clinical counterparts. Importantly, we established a blood-based biomarker assay using tumor cell-free DNA to measure systemic tumor burden longitudinally in living mice during drug therapy. A PI3K inhibitor, BKM120, was tested in our patient-derived xenograft model leading to disease attenuation and prolonged survival. Isoform-specific small interfering RNA knockdowns and isoform-selective PI3K inhibitors identified PI3K-δ as required for tumor proliferation. Additional studies showed a synergistic combination of PI3K-α/δ inhibitors with histone deacetylase inhibitors. The strong preclinical efficacy of this potent combination against multiple patient-derived xenograft models makes it an excellent candidate for further clinical development.

Integration of multiple biological contexts reveals principles of synthetic lethality that affect reproducibility

Synthetic lethal screens have the potential to identify new vulnerabilities incurred by specific cancer mutations but have been hindered by lack of agreement between studies. In the case of KRAS, we identify that published synthetic lethal screen hits significantly overlap at the pathway rather than gene level. Analysis of pathways encoded as protein networks could identify synthetic lethal candidates that are more reproducible than those previously reported. Lack of overlap likely stems from biological rather than technical limitations as most synthetic lethal phenotypes are strongly modulated by changes in cellular conditions or genetic context, the latter determined using a pairwise genetic interaction map that identifies numerous interactions that suppress synthetic lethal effects. Accounting for pathway, cellular and genetic context nominates a DNA repair dependency in KRAS-mutant cells, mediated by a network containing BRCA1. We provide evidence for why most reported synthetic lethals are not reproducible which is addressable using a multi-faceted testing framework.

Are thalassemia patients oxidatively challenged?

Background

Repeated blood transfusions is the mainstay of treatment for beta thalassemia major patients. Multiple blood transfusions lead to significant iron overload in these patients. Iron overload causes liberation of oxygen free radicals and peroxidative lipid injury. This study has been designed to study whether thalassemics suffer from oxidative injury. It also aims to study the quantum of oxidative injury.

Methods

It is a cross sectional study using cases and controls. Thirty thalassemic patients receiving multiple blood transfusions were included in this study and thirty healthy age and sex matched controls were recruited for the study. Serum ferritin levels, malondialdehyde, nitric oxide levels were estimated.

Results

Levels of all the three parameters were significantly increased (p < 0.05) in the cases compared to controls. Mean levels of all three parameters were correlated with serum ferritin levels and number of blood transfusions in increasing order. All the parameters showed fair degree of correlation (r ≥ 0.25, p ≤ 0.05).

Conclusion

Thalassemic patients receiving multiple blood transfusion suffer from iron overload which results in increased oxidative stress.

Characterization of beta-lactamase and biofilm producing Enterobacteriaceae isolated from organized and backyard farm ducks

This study was undertaken to detect the occurrence of beta-lactamase and biofilm producing Enterobacteriaceae in healthy ducks. A total 202 cloacal swabs were collected from ducks kept in organized (n = 92) and backyard (n = 110) farms in West Bengal (India). The ducks had no history of antibiotic intake. Among the 87 phenotypically beta-lactamase producing Escherichia coli, 19 (17·43%), 6 (5·05%) and 15 (13·76%) isolates possessed bla_TEM , bla_SHV and bla_CTX-M respectively. Whereas, 5 (38·46%) Salmonella isolates were found to harbour bla_CTX-M . In K. pneumoniae 10 (33·33%), 3 (13·33%), 4 (13·33%) isolates possessed bla_TEM , bla_SHV and bla_CTX-M respectively. The sequences of selected PCR products were found 98% cognate with bla_CTX-M-9, bla_SHV-12 and bla_TEM-1 . Beta-lactamase producing E. coli isolates belonged to 14 different serogroups such as O1, O2, O3, O5, O7, O8, O35, O83, O84, O88, O119, O128, O145 and O157. Moreover, 87 E. coli (79·82%), six Samonella (46·15%) and 13 K. pneumoniae (43·33%) isolates were detected as AmpC producers possessing bla_AmpC . Majority of E. coli (46·79%), Salmonella (46·15%) and K. pneumoniae (70%) isolates were detected as biofilm producers and possessed the associated genes (csgA, sdiA, rcsA, rpoS). Significantly higher occurrence of beta-lactamase and biofilm producing Enterobacteriaceae isolates was detected in backyard ducks than organized farms. SIGNIFICANCE AND IMPACT OF THE STUDY: Consumption of antibiotic through feed or during therapy is considered as potential reason for generation of antimicrobial resistant bacteria in birds. This study provides valuable evidence that exposure to contaminated environment may be an additional source for generation of antimicrobial resistant bacteria in backyard ducks. The backyard ducks are reared by marginal farmers in India who cannot offer antibiotics to them either through feed or during therapy due to high cost. The study also reveals a significant correlation between biofilm formation and possession of antimicrobial resistance genes in the bacterial isolates from the ducks.

A Quantitative Chemotherapy Genetic Interaction Map Reveals Factors Associated with PARP Inhibitor Resistance

Chemotherapy is used to treat most cancer patients, yet our understanding of factors that dictate response and resistance to such drugs remains limited. We report the generation of a quantitative chemical-genetic interaction map in human mammary epithelial cells charting the impact of the knockdown of 625 genes related to cancer and DNA repair on sensitivity to 29 drugs, covering all classes of chemotherapy. This quantitative map is predictive of interactions maintained in other cell lines, identifies DNA-repair factors, predicts cancer cell line responses to therapy, and prioritizes synergistic drug combinations. We identify that ARID1A loss confers resistance to PARP inhibitors in cells and ovarian cancer patients and that loss of GPBP1 causes resistance to cisplatin and PARP inhibitors through the regulation of genes involved in homologous recombination. This map helps navigate patient genomic data and optimize chemotherapeutic regimens by delineating factors involved in the response to specific types of DNA damage.

T-Cell Responses in Adults During Natural Respiratory Syncytial Virus Infection

Background

The pathogenesis of respiratory syncytial virus (RSV) in older adults may be due to age-related T-cell immunosenescence. Thus, we evaluated CD4 and CD8 T-cell responses during RSV infection in adults across the age spectrum.

Methods

Peripheral blood mononuclear cells collected during RSV infection in adults, age 26-96 years, were stimulated with live RSV and peptide pools representing F, M, NP, and G proteins and analyzed by flow cytometry.

Results

There were no significant age-related differences in frequency of CD4+ T cells synthesizing interferon (IFN)γ, interleukin (IL)2, IL4, IL10, or tumor necrosis factor (TNF)α or in CD8+IFNγ+ T cells. IL4+CD4+ T-cell numbers were low, as were IL13 and IL17 responses. However, in univariate analysis, CD4 T-cell IFNγ, IL2, IL4, IL10, and TNFα responses and CD8+IFNγ+ T cells were significantly increased with more severe illness requiring hospitalization. In multivariate analysis, viral load was also associated with increased T-cell responses.

Conclusions

We found no evidence of diminished RSV-specific CD4 or CD8 T-cell responses in adults infected with RSV. However, adults with severe disease seemed to have more robust CD4 and CD8 T-cell responses during infection, suggesting that disease severity may have a greater association with T-cell responses than age.

Variability of the EG95 antigen-coding gene of Echinococcus granulosus in animal and human origin: implications for vaccine development

In the present study, the genetic variability of the EG95 protein-coding gene in several animal and human isolates of Echinococcus granulosus was investigated. A total of 24 isolates collected from cattle, buffalo, sheep, goat, dog and man were amplified by Eg95-coding gene-specific primers. From the generated sequence information, a conceptual amino acid sequence was deduced. Phylogenetically, the Eg95 coding gene belongs to the Eg95-1/Eg95-2/Eg95-3/Eg95-4 cluster. Further confirmation on the maximum composite likelihood analysis revealed that the overall transition/transversion bias was 2.913. This finding indicated thatthere is bias towards transitional and transversional substitution. Using artificial neural networks, a B-cell epitope was predicted on primary sequence information. Stretches of amino acid residues varied between animal and human isolates when hydrophobicity was considered. Flexibility also varied between larval and adult stages of the organism. This observation is important to develop vaccines. However, cytotoxic T-lymphocyte epitopes on primary sequence data remained constant in all isolates. In this study, agretope identification started with hydrophobic amino acids. Amino acids with the same physico-chemical properties were present in the middle. The conformational propensity of the Eg95-coding gene of 156 amino acid residues had α-turns and β-turns, and α-amphipathic regions up to 129, 138-156 and 151-155 residues, respectively. The results indicated potential T-cell antigenic sites. The overall Tajima's D value was negative (-2.404165), indicative of negative selection pressure.

Targeting the evolution of drug resistance in lung cancer

Even in their intended disease subset, Epithelial Growth Factor Receptor tyrosine kinase inhibitors leave behind residual disease eventually resulting in acquired resistance. Our study indicates that this process is driven by Aurora Kinase A. Inhibition of Aurora signaling may prevent the onset of acquired resistance and counteract progressive disease.