Abstract PO-079: Proteomic profiling reveals subtype specific kinase expression in pancreatic cancer

Pancreatic adenocarcinoma (PDAC) remains an extremely lethal disease with few effective therapeutic options. Targeted therapy development has remained largely unsuccessful due to complex tumor heterogeneity and better molecular indicators of response are urgently needed. We have previously identified two distinct molecular tumor subtypes in PDAC, basal-like and classical, which are prognostic and dictate response to chemotherapy. We have also developed a patient derived xenograft (PDX) mouse model that maintains the integrity of patient tumor biology and recapitulates primary tumor subtypes in vivo. Here, we aim to utilize multiplexed kinase inhibitor beads and quantitative mass spectrometry (MIB-MS) to determine baseline kinase expression and adaptive kinome responses to therapy in PDAC PDX tumors. A total of 381 kinases were identified across all samples and tumor specific kinases were isolated by alignment to human peptides. Distinct kinase expression profiles were observed for basal-like and classical tumors. Basal-like tumors showed high expression of kinases involved in receptor tyrosine kinase activity, MAP kinase activity, and clathrin-dependent endocytosis. Classical subtype tumors showed increased expression of kinases involved in metabolism and cytoskeletal regulatory kinases. Differential protein expression was further validated by differential gene expression using RNAseq. MIB profiling of kinome response to EGFR inhibition by erlotinib indicated kinome reprogramming with upregulation of microtubule associated kinases and MAP kinase family members. Overall, these results suggest that basal-like and classical subtype tumors exhibit distinct kinome profiles that present possible subtype specific vulnerabilities to kinase inhibition. Stratifying kinase inhibitor therapies based on tumor subtype could improve response to targeted therapies in PDAC.

Citation Format: Yi Xu, Michael East, Ashley Morrison, Gabriela Herrera, Laura Peng, Gary Johnson, Jen Jen Yeh. Proteomic profiling reveals subtype specific kinase expression in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-079.

CSIG-10. GENOTYPE – KINOME GUIDED DEVELOPMENT OF PRECISION EGFR-TARGETED THERAPEUTICS FOR GLIOBLASTOMA

Glioblastoma (GBM) is an aggressive primary brain tumor with poor survival and limited treatment options. However, it is an attractive candidate for precision therapeutic approaches due to the frequency of amplification and/or activating mutations in the epidermal growth factor receptor (EGFR) gene and the availability of several brain penetrant second- and third-generation EGFR tyrosine kinase inhibitors (TKI). We used comprehensive molecular profiling of a panel of genetically engineered mouse astrocyte models to examine whether mutational profiles, particularly EGFR and PTEN status, could be used to identify kinases upregulated in specific mutational backgrounds. Using RNA-seq and multiplex inhibitor bead/mass spectrometry (MIB-MS) to analyze the kinase transcriptomes and proteomes, respectively, we have identified several potential targets for combination therapy. Overexpression of wild type EGFR in immortalized, Cdkn2a-/- astrocytes resulted in mild rewiring of the GBM kinome. Only 5 kinases aside from EGFR itself were overexpressed on either the transcript or protein levels. One overexpressed kinase, Hck, has been shown to be involved in cell survival, proliferation, adhesion, and migration. In contrast, overexpression of EGFRvIII, a constitutively active, extracellular domain truncation mutant of EGFR, resulted in significant alteration of the GBM kinome – 81 kinases showed differential expression, with 27 upregulated. One potentially attractive target among these was Cdk6, a drug-targetable, prognostically significant cyclin-dependent kinase implicated in proliferation, migration, and invasion. Finally, overexpression of EGFRvIII in cells lacking Pten dysregulated 46 kinases, including 15 upregulated. One particularly interesting target in these cells was Ddr2, a tyrosine kinase involved in migration, invasion, and extracellular matrix remodeling. We conclude that Hck, Cdk6, and Ddr2 represent attractive targets for therapeutic intervention in their relevant genetic contexts. These findings also suggest that molecular diagnostics for EGFR and PTEN status may be useful in guiding development of rational, EGFR TKI-centric drug combinations.

DRES-13. DUAL KINASE INHIBITION TO COMBAT EGFR-INHIBITOR RESISTANCE IN GLIOBLASTOMA

Glioblastoma (GBM) is an aggressive primary brain tumor with a poor survival rate. One of the most common molecular alterations seen in GBM is amplification and/or mutation of the Epidermal Growth Factor Receptor (EGFR), which has made it an attractive therapeutic target. However, several EGFR tyrosine kinase inhibitors have been tested clinically in GBM with minimal success. One reason for this lack of efficacy could be due to acute, adaptive resistance via alternative pathway activation. To investigate this mechanism of tumor resistance, we used RNA-seq and multiplex inhibitor bead/mass spectrometry (MIB-MS) to analyze the transcriptomes and kinomes of genetically engineered murine astrocytes with common GBM genotypes. We have previously shown that 38% of the expressed kinome varied among a panel of diverse nGEM astrocytes harboring Cdkn2a deletion (C) plus Pten deletion (CP), wild-type human EGFR (CE) or EGFRvIII (CEv3) overexpression or both EGFRvIII overexpression and Pten deletion (CEv3P). Although CE have a similar transcriptional profile to C cells at baseline, when treated with the EGFR inhibitor afatinib, CE respond more similarly to CEv3 cells. When cells containing endogenous murine EGFR (C and CP) are treated with afatinib, fewer than 0.5% of kinases showed differential expression. In cells with EGFR overexpression alone, more than 6% of kinases were differentially expressed upon afatinib treatment, including Ntrk3, Fgfr2 and 3, Lyn, Bmx, Epha2 and 5, Fn3k, a kinase involved in fructosamine processing, and Nrbp2, a kinase involved in regulation of apoptosis. This effect was blunted in cells lacking Pten in addition to having EGFRvIII (CEv3P), resulting in less than 2% of kinases being differentially expressed. The only kinase upregulated in all three EGFR-overexpressing cell types was Coq8a, which is involved in electron transport and response to DNA damage. Given this overlap in response, Coq8a could be a potential dual treatment target for GBM.

Effects of providing total mixed rations indoors and on pasture on the behavior of lactating dairy cattle and their preference to be indoors or on pasture

Grazing is considered a normal behavior for dairy cattle, although they may not be able to meet their nutritional requirements from grazing alone, and so to sustain higher yields requires access to a total mixed ration (TMR). The study aim was to provide dairy cows with access to TMR indoors and on pasture to establish influence on behavior and preference for each location. The study took place from August to November, 2009, using 36 late-lactation Holstein-Friesian dairy cows. The cows were allocated to 1 of 3 26-d study periods (n=12×3). Within each period the cows were further divided into a control (n=6) or treatment (n=6) group using a crossover design, where the cows were changed between the control and treatment group after 13 d. Treatment cows had access to TMR indoors and on pasture, whereas control cows only had access to TMR indoors. Following a.m. and p.m. milkings the cows were taken to a point equidistant between indoors and pasture and given the choice of going to pasture (1.5 ha) or to a freestall barn. Between milkings the cows had free access between the locations. Initial choice was recorded and a video camera was used to record time spent in each location. Behavior observations were recorded to establish how the cows spent their time during the day. To determine what factors influenced preference, weather conditions, milk yield, body condition score, and lameness were recorded. Initially, the cows chose indoors following milking (96.4±0.80%). Overall, the cows expressed a partial preference for pasture (71.1±1.82%), which was different from 100, 50, and 0%. Study period influenced preference with cows spending less time on pasture as the season progressed (86.7 vs. 68.3 vs. 58.3% for study periods 1, 2, and 3, respectively). Providing the cows with TMR outdoors did not affect pasture use, but resulted in an increase in TMR intake of 2.2±0.41 kg of dry matter/d. The cows spent more time on pasture as the temperature-humidity index indoors (55.6±0.92) and outdoors (54.6±0.82) increased, but rainfall and milk yield did not influence preference. Cows with lameness score >1.5 spent more time indoors (35.4±4.52 vs. 25.2±2.64% for cows with >1.5 vs. ≤1.5 lameness score, respectively). In conclusion, the cows expressed a partial preference for pasture, which was not influenced by providing TMR on pasture.

Topiramate induced acute angle closure glaucoma

Topiramate is an oral sulphamate medication primarily used for seizure, migraine and neuropathic pain. It has been associated with secondary angle closure, which can mimic acute angle closure glaucoma. Suspicion for medication induced angle closure glaucoma should be higher whenever angle closure presents bilaterally. We present two cases of bilateral angle closure glaucoma secondary to topiramate.

Crystal structure analysis of warfarin binding to human serum albumin: anatomy of drug site I

Human serum albumin (HSA) is an abundant transport protein found in plasma that binds a wide variety of drugs in two primary binding sites (I and II) and can have a significant impact on their pharmacokinetics. We have determined the crystal structures at 2.5 A-resolution of HSA-myristate complexed with the R-(+) and S-(-) enantiomers of warfarin, a widely used anticoagulant that binds to the protein with high affinity. The structures confirm that warfarin binds to drug site I (in subdomain IIA) in the presence of fatty acids and reveal the molecular details of the protein-drug interaction. The two enantiomers of warfarin adopt very similar conformations when bound to the protein and make many of the same specific contacts with amino acid side chains at the binding site, thus accounting for the relative lack of stereospecificity of the HSA-warfarin interaction. The conformation of the warfarin binding pocket is significantly altered upon binding of fatty acids, and this can explain the observed enhancement of warfarin binding to HSA at low levels of fatty acid.

Pilot study of intra-arterial cisplatin and intravenous vinblastine and dacarbazine in patients with melanoma in-transit metastases

For melanoma, in-transit metastases (ITMs) are a harbinger of systemic disease in over 70% of patients and thus warrant a systemic approach to management. In this study, previously untreated patients with ITMs (n=15) received a systemic regimen of 'CVD' in 21 day cycles (median, three cycles) as follows: dacarbazine 800 mg/m2 intravenously (i.v.) on day 1, vinblastine 1.6 mg/m2 i.v. on days 1-5, and cisplatin (CDDP) 100 mg/m2 by 24 h intra-arterial (i.a.) infusion in 1l of heparinized saline via the iliac or subclavian artery on day 3. There were three clinical complete responses (CRs) in patients with a modest burden of ITMs (< 3 cm in size) and seven partial responses (PRs), yielding a 67% response rate (95% confidence interval, 38-88%). One of the clinical CRs had microscopic residual disease at surgery (a pathological PR). The times to progression (TTP) for the CRs were 5, 21 and 38+ months; the median TTP for the PRs was 4.5 months (range, 2-10 months). Overall median survival was 31 months. Systemic toxicities were similar to those induced by i.v. CVD. However, patients noted more pronounced paraesthesia in the infused extremity. Also, two patients experienced severe CDDP-induced burns, one patient developed brachial plexopathy, and one patient had a haemorrhage in an occult brain metastasis. The high clinical activity of this regimen will have to be confirmed in more patients before a first-pass i.a. advantage can be claimed. Furthermore, the dose, schedule and technique of i.a. CDDP delivery must be further refined before it can be routinely incorporated in regimens as an alternative to isolated regional hyperthermic perfusion, which is technically more difficult and is not readily available in community-based hospitals.

Luminal dissociation of Ca2+ from the phosphorylated Ca2+-ATPase is sequential and gated by Mg2+

Transport of Ca2+ across the membrane by the Ca2+-ATPase of skeletal muscle sarcoplasmic reticulum involves the transfer of two Ca2+ ions from a pair of cytoplasmic sites to a pair of luminal sites, driven by phosphorylation of the ATPase. The ATPase is inhibited by Mg2+ at alkaline pH values. Inhibition follows from a decrease in the rate of release of Ca2+ from the phosphorylated ATPase. Phosphorylation-induced release of Ca2+ from the ATPase is biphasic at alkaline pH, which is consistent with sequential release of Ca2+ from the phosphorylated ATPase; the rates of both components decrease with increasing Mg concentration. The effect of Mg2+ on the slow phase of release follows from the binding of Mg2+ at the empty outer luminal site, vacated by the release of the first Ca2+ ion. The effect of Mg2+ on the rate of release of the first Ca2+ ion could follow from binding to a gating site also affecting the binding of Ca2+ to the cytoplasmic sites.

Genetic characterization of canine distemper virus in Serengeti carnivores

The lion (Panthera leo) population in the Serengeti ecosystem was recently afflicted by a fatal epidemic involving neurological disease, encephalitis and pneumonia. The cause was identified as canine distemper virus (CDV). Several other species in the Serengeti were also affected. This report presents CDV H and P gene sequences isolated from Serengeti lions (Panthera leo), spotted hyenas (Crocuta crocuta), bat-eared fox (Otocyon megalotis) and domestic dog (Canis familiaris). Sequence analyses demonstrated that the four Serengeti species carry closely related CDV isolates which are genetically distinct from other CDV isolates from various species and locations. The results are consistent with the conclusions that: (1) a particularly virulent strain of CDV emerged among Serengeti carnivores within the last few years; (2) that strain has recognizable shared-derived (synapomorphic) genetic differences in both H and P genes when compared to CDV from other parts of the world; and (3) that the CDV strain has frequently crossed host species among Serengeti carnivores.

Canine distemper virus infection in Serengeti spotted hyenas

Clinical signs suggestive of canine distemper virus (CDV) infection were observed among a group of spotted hyenas (Crocuta crocuta) in the Serengeti, Tanzania. Virus antigen was detected immunohistologically in a brain sample from a diseased cub. The presence of virus RNA could be demonstrated in this brain as well as in intestine and lymph node of the animal by RT-PCR. Sequence comparison of brain-derived amplicons showed that the virus was related to recent CDV field isolates. The closest homology (>99 percent) was to a recently described CDV which caused high mortality in sympatric lions.

Comparative costs of laparoscopically assisted vaginal hysterectomy

AIM

To audit the performance of laparoscopically assisted vaginal hysterectomy (LAVH) in a gynaecological practice with regard to cost and clinical outcome when compared to the surgical alternatives available.

METHOD

LAVH was performed on 50 women and both monetary and time cost parameters analysed and compared with those of 30 women undergoing either abdominal hysterectomy, vaginal hysterectomy or endometrial resection.

RESULTS

The cost of LAVH was approximately twice that of abdominal hysterectomy and almost three times that of vaginal hysterectomy. The theatre time was longer for LAVH than for the above and in a similar ratio. Patient recovery was superior with LAVH when compared with abdominal hysterectomy but not when compared with standard vaginal hysterectomy.

CONCLUSION

LAVH has a role in providing patients with the option of avoiding abdominal hysterectomy, although the role will differ depending upon the differing criteria used by surgeons for selecting patients for standard vaginal hysterectomy.

Lymphoscintigraphy in melanoma: initial evaluation of a low protein dose monoclonal antibody cocktail

A low protein dose (73 +/- 10 micrograms total) 131I-labeled monoclonal antibody cocktail made of equal microgram quantities of 225.28S (IgG2a) and 763.24T (IgG1) murine monoclonal antibodies, which bind additively to a high molecular weight antigen of melanoma, was evaluated as a lymphoscintigraphic agent in 17 patients with intermediate to thick (mean Breslow depth, 3.39 +/- 0.64 mm) melanomas or clinical Stage II disease scheduled for nodal dissection. Eleven of the patients were clinically Stage I while 6 were clinically Stage II. 131I antibody cocktail, 258 +/- 10 microCi, was administered s.c. at the site of the primary melanoma or its scar following surgical removal. In eight patients, 63 +/- 8 microCi of 125I nonspecific normal sheep IgG was coadministered s.c. Gamma camera imaging was conducted beginning immediately after and continuing for several days following injection. Surgical resection, weighing, and gamma counting of the draining lymph nodes were undertaken in all patients. On gamma scans, early nodal uptake of antibody was most pronounced and of longest duration in the tumor pathologically positive patients (5 of 7 had visible nodal uptake, 4 of 7 visually stable or rising with time), with the t 1/2 of nodal clearance by gamma scan significantly (P less than 0.05) longer than in the negative patients in whom 4 of 10 showed some, although generally transient (0 of 10 stable or rising), nodal uptake. Scans were not easily interpretable when the injection site was very near the draining nodal group, in part due to the detection of scatter activity from the injection site. In several instances the scan was correct and the clinical examination was incorrect as regards nodal disease. Quantitative analysis of the surgically excised draining nodes showed significantly (P less than 0.001) more 131I anti-melanoma antibody uptake in the 21 tumor-involved nodes [0.01217% injected dose (ID)/node median] than in the 512 tumor-negative nodes (0.00051% ID/node median). Median percentage ID/g of anti-melanoma antibody in tumor-involved nodes was significantly greater (P less than 0.01) than in tumor-negative nodes (0.01984 versus 0.003215% ID/g). 125I-labeled nonspecific antibody did not accumulate significantly more in the tumor-involved nodes on a per node or per g basis in the 283 of 533 nodes studied using the dual-label approach (0.0036 versus 0.00092% ID/g). These data demonstrate that by external imaging and by tissue counting that a radiolabeled anti-melanoma monoclonal antibody cocktail can specifically accumulate to melanoma-involved lymph nodes following s.c. administration.(ABSTRACT TRUNCATED AT 400 WORDS)