Mannose receptor (CD206) activation in tumor-associated macrophages enhances adaptive and innate antitumor immune responses

Solid tumors elicit a detectable immune response including the infiltration of tumor-associated macrophages (TAMs). Unfortunately, this immune response is co-opted into contributing toward tumor growth instead of preventing its progression. We seek to reestablish an antitumor immune response by selectively targeting surface receptors and endogenous signaling processes of the macrophage subtypes driving cancer progression. RP-182 is a synthetic 10-mer amphipathic analog of host defense peptides that selectively induces a conformational switch of the mannose receptor CD206 expressed on TAMs displaying an M2-like phenotype. RP-182-mediated activation of this receptor in human and murine M2-like macrophages elicits a program of endocytosis, phagosome-lysosome formation, and autophagy and reprograms M2-like TAMs to an antitumor M1-like phenotype. In syngeneic and autochthonous murine cancer models, RP-182 suppressed tumor growth, extended survival, and was an effective combination partner with chemo- or immune checkpoint therapy. Antitumor activity of RP-182 was also observed in CD206^high patient-derived xenotransplantation models. Mechanistically, via selective reduction of immunosuppressive M2-like TAMs, RP-182 improved adaptive and innate antitumor immune responses, including increased cancer cell phagocytosis by reprogrammed TAMs.

Effects of treatment with formoterol on bronchoprotection against methacholine

PURPOSE

In addition to their bronchodilatory effects, beta(2)-agonists protect against bronchoconstriction, such as that caused by methacholine challenge. However, tachyphylaxis to this beneficial effect develops after chronic use of beta(2)-agonists. We studied whether the frequency or dose of treatment with a long-acting beta(2)-agonist (formoterol) affects the degree of bronchoprotection afforded against methacholine challenge and to compare this with the effects of a short-acting beta(2)-agonist (terbutaline).

PATIENTS AND METHODS

In a randomized, parallel group, double-blind study at two centers, patients with stable asthma of mild to moderate severity who were treated with inhaled corticosteroids were treated with formoterol 6 micrograms twice daily, 24 micrograms twice daily, 12 micrograms once daily; terbutaline 500 micrograms four times daily; or placebo. Treatments were given by dry powder inhaler for a period of 2 weeks. Of the 72 patients who were enrolled, 67 completed the study. Methacholine challenge was performed to calculate the provocative dose that caused a 20% fall in forced expiratory volume in 1 second at baseline (unprotected) after an initial 1-week run-in without beta(2)-agonists, 1 hour after the first dose of study treatment, and again 1 hour after 7 and 14 days of study treatment.

RESULTS

Each of the four active treatments exhibited significant tachyphylaxis (P < 0.05) to protection against methacholine challenge when comparing first/last dose (as geometric mean protection ratio versus baseline): formoterol 24 micrograms twice daily (9.6-fold/1.6-fold), 12 micrograms once daily (7.1-fold/2.2-fold), 6 micrograms twice daily (6.2-fold/2.3-fold), and terbutaline 500 micrograms four times daily (2.9-fold/2.0-fold). There were no significant differences among treatments after 2 weeks in bronchoprotection against methacholine challenge. For all formoterol regimens, the bronchodilator response 1 hour after inhalation was maintained over the 2-week treatment period. Diurnal control of morning and evening peak flow was significantly better with formoterol 24 micrograms twice daily than with terbutaline.

CONCLUSIONS

Tachyphylaxis to bronchoprotection against methacholine challenge develops after 2 weeks of therapy with formoterol, a long-acting beta(2)-agonist, at all three dosage regimens that were tested. In contrast, the bronchodilator effects of formoterol were maintained during the 2 weeks of treatment.

Gender Differences in Entrustable Professional Activity Evaluations of General Surgery Residents

OBJECTIVE

To determine differences in entrustable professional activity (EPA) assessments between male and female general surgery residents.

SUMMARY BACKGROUND DATA

Evaluations play a critical role in career advancement for physicians. However, female physicians in training receive lower evaluations and underrate their own performance. Competency-based assessment frameworks, such as EPAs, may help address gender bias in surgery by linking evaluations to specific, observable behaviors.

METHODS

In this cohort study, EPA assessments were collected from July 2018 to May 2020. The effect of resident sex on EPA entrustment levels was analyzed using multiple linear and ordered logistic regressions. Narrative comments were analyzed using latent dirichlet allocation to identify topics correlated with resident sex.

RESULTS

Of the 2480 EPAs, 1230 EPAs were submitted by faculty and 1250 were submitted by residents. After controlling for confounding factors, faculty evaluations of residents were not impacted by resident sex (estimate = 0.09, P = 0.08). However, female residents rated themselves lower by 0.29 (on a 0-4 scale) compared to their male counterparts (P < 0.001). Within narrative assessments, topics associated with resident sex demonstrated that female residents focus on the "guidance" and "supervision" they received while performing an EPA, while male residents were more likely to report "independent" action.

CONCLUSIONS

Faculty assessments showed no difference in EPA levels between male and female residents. Female residents rate themselves lower by nearly an entire post graduate year (PGY) level compared to male residents. Latent dirichlet allocation -identified topics suggest this difference in self-assessment is related to differences in perception of autonomy.

Effects of sodium acetate, bicarbonate and lactate on acid-base status in anaesthetized dogs

Equal doses of sodium acetate, bicarbonate and lactate (6.6 mEq/L) infused intravenously over 30 min into three groups of halothane-anaesthetized dogs caused changes in acid-base status. Arterial carbon dioxide tension (PaCO2), pHa, base excess (BE) and standard bicarbonate (SB) increased. Sodium bicarbonate caused the most rapid and greatest changes. The bicarbonate group was significantly different (P less than 0.05) from the other groups at 15 and 30 min after the start of infusion for pHa, BE and SB. The greater effects of bicarbonate are due to its production of alkalinization without a requirement for metabolism; acetate and lactate require oxidation to be effective. The acetate and bicarbonate groups were not statistically different at 45 min after the onset of drug infusion, but both had significantly higher SB and BE mean values than the lactate group. All measurements made after 45 min revealed no significant differences among groups. Thus, after the earlier differences noted above, the three alkalinizers caused similar effects on acid-base status. PaCO2 was elevated in all groups, but there were no differences among groups. Cardiovascular effects caused by infusion of the three drugs were minimal.

Loss of PDPK1 abrogates resistance to gemcitabine in label-retaining pancreatic cancer cells

BACKGROUND

Label-retaining cancer cells (LRCC) have been proposed as a model of slowly cycling cancer stem cells (CSC) which mediate resistance to chemotherapy, tumor recurrence, and metastasis. The molecular mechanisms of chemoresistance in LRCC remain to-date incompletely understood. This study aims to identify molecular targets in LRCC that can be exploited to overcome resistance to gemcitabine, a standard chemotherapy agent for the treatment of pancreas cancer.

METHODS

LRCC were isolated following Cy5-dUTP staining by flow cytometry from pancreatic cancer cell lines. Gene expression profiles obtained from LRCC, non-LRCC (NLRCC), and bulk tumor cells were used to generate differentially regulated pathway networks. Loss of upregulated targets in LRCC on gemcitabine sensitivity was assessed via RNAi experiments and pharmacological inhibition. Expression patterns of PDPK1, one of the upregulated targets in LRCC, was studied in patients' tumor samples and correlated with pathological variables and clinical outcome.

RESULTS

LRCC are significantly more resistant to gemcitabine than the bulk tumor cell population. Non-canonical EGF (epidermal growth factor)-mediated signal transduction emerged as the top upregulated network in LRCC compared to non-LRCC, and knock down of EGF signaling effectors PDPK1 (3-phosphoinositide dependent protein kinase-1), BMX (BMX non-receptor tyrosine kinase), and NTRK2 (neurotrophic receptor tyrosine kinase 2) or treatment with PDPK1 inhibitors increased growth inhibition and induction of apoptosis in response to gemcitabine. Knockdown of PDPK1 preferentially increased growth inhibition and reduced resistance to induction of apoptosis upon gemcitabine treatment in the LRCC vs non-LRCC population. These findings are accompanied by lower expression levels of PDPK1 in tumors compared to matched uninvolved pancreas in surgical resection specimens and a negative association of membranous localization on IHC with high nuclear grade (p < 0.01).

CONCLUSION

Pancreatic cancer cell-derived LRCC are relatively resistant to gemcitabine and harbor a unique transcriptomic profile compared to bulk tumor cells. PDPK1, one of the members of an upregulated EGF-signaling network in LRCC, mediates resistance to gemcitabine, is found to be dysregulated in pancreas cancer specimens, and might be an attractive molecular target for combination therapy studies.

Readmissions From Venous Thromboembolism After Complex Cancer Surgery

IMPORTANCE

Venous thromboembolism (VTE) is a major cause of preventable morbidity and mortality after cancer surgery. Venous thromboembolism events that are significant enough to require hospital readmission are potentially life threatening, yet data regarding the frequency of these events beyond the 30-day postoperative period remain limited.

OBJECTIVE

To determine the rates, outcomes, and predictive factors of readmissions owing to VTE up to 180 days after complex cancer operations, using a national data set.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of the 2016 Nationwide Readmissions Database was performed to study adult patients readmitted with a primary VTE diagnosis. Data obtained from 197 510 visits for 126 104 patients were analyzed. This was a multicenter, population-based, nationally representative study of patients who underwent a complex cancer operation (defined as cystectomy, colectomy, esophagectomy, gastrectomy, liver/biliary resection, lung/bronchus resection, pancreatectomy, proctectomy, prostatectomy, or hysterectomy) from January 1 through September 30, 2016, for a corresponding cancer diagnosis.

EXPOSURES

Readmission with a primary diagnosis of VTE.

MAIN OUTCOMES AND MEASURES

Proportion of 30-, 90-, and 180-day VTE readmissions after complex cancer surgery, factors associated with readmissions, and outcomes observed during readmission visit, including mortality, length of stay, hospital cost, and readmission to index vs nonindex hospital.

RESULTS

For the 126 104 patients included in the study, 30-, 90-, and 180-day VTE-associated readmission rates were 0.6% (767 patients), 1.1% (1331 patients), and 1.7% (1449 of 83 337 patients), respectively. A majority of patients were men (58.7%), and the mean age was 65 years (SD, 11.5 years). For the 1331 patients readmitted for VTE within 90 days, 456 initial readmissions (34.3%) were to a different hospital than the index surgery hospital, median length of stay was 5 days (IQR, 3-7 days), median cost was $8102 (IQR, $5311-$10 982), and 122 patients died (9.2%). Independent factors associated with readmission included type of operation, scores for severity and risk of mortality, age of 75 to 84 years (odds ratio [OR], 1.30; 95% CI, 1.02-1.78), female sex (OR, 1.23; 95% CI, 1.11-1.37), nonelective index admission (OR, 1.31; 95% CI, 1.03-1.68), higher number of comorbidities (OR, 1.30; 95% CI, 1.06-1.60), and experiencing a major postoperative complication during the index admission (OR, 2.08; 95% CI, 1.85-2.33).

CONCLUSIONS AND RELEVANCE

In this cohort study, VTE-related readmissions after complex cancer surgery continued to increase well beyond 30 days after surgery. Quality improvement efforts to decrease the burden of VTE in postoperative patients should measure and account for these late VTE-related readmissions.

What Drives High Costs of Cytoreductive Surgery and HIPEC: Patient, Provider or Tumor?

INTRODUCTION

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is utilized for peritoneal malignancies and is associated with significant resource use. To address potentially modifiable factors contributing to excessive cost, we sought to determine predictors of high cost of care for patients undergoing CRS/HIPEC.

METHODS

An institutional CRS/HIPEC database was queried for adult patients from 2014 to 2018. Cost was defined as cost for the index hospitalization, and high-cost cases were defined as > 75th percentile for cost. Bivariate analyses for cost were performed, and all significant tumor, patient, and surgeon-specific variables were entered in a linear regression for cost. A separate linear regression was performed for length of stay (LOS).

RESULTS

In total, 59 patients underwent 61 CRS/HIPEC procedures. The median direct variable cost was $20,509 (16,395-25,240). Median length of stay (LOS) was 8 (7-11.5) days and ICU stay was 1 (1-1.5) day. LOS, length of ICU stay and operative time were predictive of cost. Factors associated with increased LOS were Clavien-Dindo grade II complications and ostomy creation. Patient-related factors, including age and BMI, tumor-related factors, such as PCI and CCR, and surgeon were not predictive of cost nor LOS.

DISCUSSION

Our results, the first to identify predictors of high cost of CRS/HIPEC-related care in the US, reveal cost was largely related to length and intensity of care. In turn, these drivers were influenced by complications and operative factors. Future work will focus on identifying an appropriate ERAS protocol following CRS/HIPEC and selection of those patients that may avoid routine ICU admission.

Operative Delay in Adults with Appendicitis: Time is Money

BACKGROUND

Evidence suggests that operative delay of up to 24 h is not associated with adverse outcomes among patients undergoing emergent appendectomy. However, the fiscal implication of operative delay is not well described in adults. We sought to examine the effect of delayed appendectomy on clinical outcomes and hospital cost.

METHODS

We conducted a retrospective cohort study of patients undergoing nonelective laparoscopic appendectomy from 2014 to 2018 at both a tertiary care center and an affiliated short-stay hospital. Using a unique data set constructed from merged electronic health record and patient-level hospital financial data, patients with delayed surgery, defined as >12 h from emergency department (ED) arrival to operation, were compared with patients who underwent surgery within 12 h. Patient-specific variables were analyzed for their association with resource utilization, and subsequent multivariable linear regression was performed for total hospital cost.

RESULTS

1372 patients underwent laparoscopic appendectomy during the study period. 938 patients (68.3%) underwent surgery within 12 h of ED arrival, and 434 patients (31.6%) underwent delayed surgery. Delayed cases had longer length of stay (44.6 ± 42.5 versus 34.5 ± 36.5 h, P < 0.01) and increased total hospital cost ($9326 ± 4691 versus $8440 ± 3404, P < 0.01). The cost difference persisted on multivariable analysis (P < 0.01). There were no significant differences between delayed cases and nondelayed cases for operative time, intraoperative findings, including rate of perforation, or postoperative complications.

CONCLUSIONS

Although safe, delayed appendectomy is associated with an increased length of stay and increased total hospital costs compared with appendectomy within 12 h of reaching the ED.

Recipient But Not Donor Adiponectin Polymorphisms Are Associated With Early Posttransplant Hepatic Steatosis in Patients Transplanted for Non-Nonalcoholic Fatty Liver Disease Indications

OBJECTIVES

De novo steatosis after liver transplant is common and can occur in up to one-third of patients who are transplanted for liver disease other than for nonalcoholic fatty liver disease. Genetic factors may influence posttransplant steatosis; in a posttransplant setting, donor or recipient genetic factors could also play roles. Genetic polymorphisms in the adiponectin gene have been associated with metabolic syndrome in the pretransplant setting. We aimed to assess the association between donor and recipient adiponectin polymorphisms and early posttransplant hepatic steatosis identified on liver biopsies.

MATERIALS AND METHODS

Clinical data were collected for 302 liver transplant patients who underwent protocol biopsies for hepatitis C. Of these, 111 patients had available biopsies and donor/recipient DNA. Patients with grade 1 steatosis or greater (35% of patients) were compared with patients without posttransplant steatosis with respect to clinical features and donor/recipient adiponectin polymorphism genotypes.

RESULTS

Patients who developed posttransplant steatosis and those without steatosis were similar with respect to individual components of metabolic syndrome. The adiponectin polymorphisms rs1501299 G/G and rs17300539 G/G genotypes in recipients were associated with early posttransplant graft steatosis. We found no associations between graft steatosis and donor adiponectin polymorphisms.

CONCLUSIONS

Genetic polymorphisms in the adiponectin gene of recipients (but not donors) are associated with early de novo posttransplant hepatic steatosis, independent of components of metabolic syndrome.

Donor IFNL4 Genotype Is Associated with Early Post-Transplant Fibrosis in Recipients with Hepatitis C

BACKGROUND AND AIMS

Early post-transplant hepatic fibrosis is associated with poor outcomes and may be influenced by donor/recipient genetic factors. The rs368234815 IFNL4 polymorphism is related to the previously described IL28B polymorphism, which predicts etiology-independent hepatic fibrosis. The aim of this study was to identify the impact of donor and/or recipient IFNL4 genotype on early fibrosis among patients transplanted for hepatitis C (HCV).

METHODS

Clinical data were collected for 302 consecutive patients transplanted for HCV. 116 patients who had available liver biopsies and donor/recipient DNA were included. 28% of these patients with stage 2 fibrosis or greater were compared to patients without significant post-transplant fibrosis with respect to clinical features as well as donor/recipient IFNL4 genotype.

RESULTS

The IFNL4 TT/TT genotype was found in 26.0% of recipients and 38.6% of donors. Patients who developed early post-transplant fibrosis had a 3.45 adjusted odds of having donor IFNL4 TT/TT genotype (p = 0.012). Donor IFNL4 TT/TT genotype also predicted decreased overall survival compared to non-TT/TT genotypes (p = 0.016).

CONCLUSIONS

Donor IFNL4 TT/TT genotype, a favorable predictor of spontaneous HCV clearance pre-transplant, is associated with increased early post-transplant fibrosis and decreased survival.

Clinical and Cost Profile of Controlled Grade B Postoperative Pancreatic Fistula: Rationale for Their Consideration as Low Risk

BACKGROUND

Despite standardization, the 2016 ISGPF criteria are limited by their wider applicability and oversimplification of grade B POPF. This work applied the 2016 ISGPF grading criteria within a US academic cancer center to verify clinical and fiscal distinctions and sought to improve grading criteria for grade B POPF.

METHODS

The 2008-2018 cost and NSQIP data from pancreaticoduodenectomy to postoperative day 90 were merged. All POPFs were coded by 2016 ISGPF criteria. The Clavien-Dindo Classification (CD) defined complication severity. On sub-analyses, grade B POPFs were divided into those with adequate drainage and those requiring additional drainage. Chi-square, ANOVA, and Fisher's least significant difference test were employed.

RESULTS

Two hundred thirty-two patients were in the final analyses, 72 (31%) of whom had POPFs: 16 (7%) biochemical leaks, 54 (23%) grade B (28% required additional drainage), and 2 (1%) grade C. There was no significant difference in length of stay, CD, readmission, or cost in patients without a POPF, with biochemical leak or grade B POPF. On sub-analyses, 92% of adequately drained grade B POPFs had CD 1-2 and readmission equivalent to patients without POPF (p > 0.05). One hundred percent of grade B POPF requiring drainage had CD 3-4a, and 67% were readmitted. Cost was significantly increased in grade B POPF requiring additional drainage (p = 0.02) and grade C POPF (p < 0.01).

CONCLUSIONS

This analysis did not confirm an incremental increase in morbidity and cost with POPF grade. Sub-analyses enabled accurate clinical and cost distinctions in grade B POPF; adequately drained grade B POPF are low risk and clinically insignificant.

Early vs Late Readmissions in Pancreaticoduodenectomy Patients: Recognizing Comprehensive Episodic Cost to Help Guide Bundled Payment Plans and Hospital Resource Allocation

INTRODUCTION

Previous studies on readmission cost in pancreaticoduodenectomy patients use estimated cost data and do not delineate etiology or cost differences between early and late readmissions. We sought to identify relationships between postoperative complication type and readmission timing and cost in pancreaticoduodenectomy patients.

METHODS

Hospital cost data from date of discharge to postoperative day 90 were merged with 2008-2018 NSQIP data. Early readmission was within 30 days of surgery, and late readmission was 30 to 90 days from surgery. Regression analyses for readmission controlled for patient comorbidities, complications, and surgeon.

RESULTS

Of 230 patients included, 58 (25%) were readmitted. The mean early and late readmission costs were $18,365 ± $20,262 and $24,965 ± $34,435, respectively. Early readmission was associated with index stay deep vein thrombosis (p < 0.01), delayed gastric emptying (p < 0.01), and grade B pancreatic fistula (p < 0.01). High-cost early readmission had long hospital stays or invasive procedures. Common late readmission diagnoses were grade B pancreatic fistula requiring drainage (n = 5, 14%), failure to thrive (n = 4, 14%), and bowel obstruction requiring operation (n = 3, 11%). High-cost late readmissions were associated with chronic complications requiring reoperation.

CONCLUSION

Early and late readmissions following pancreaticoduodenectomy differ in both etiology and cost. Early readmission and cost are driven by common complications requiring percutaneous intervention while late readmission and cost are driven by chronic complications and reoperation. Late readmissions are frequent and a significant source of resource utilization. Negotiations of bundled care payment plans should account for significant late readmission resource utilization.

Peritoneal recurrence after resection for Stage I-III colorectal cancer: A population analysis

BACKGROUND

Colorectal cancer (CRC) often recurs in the peritoneum, although the pattern of peritoneal recurrence (PR) has received less attention. We sought to describe the presentation and risk factors for PR following CRC resection.

METHODS

We performed a cohort study of patients undergoing resection of Stage I-III CRC from 2006 to 2007 using merged data from a Commission on Cancer Special Study and the National Cancer Database. We estimated the timing, method of detection, and risk factors for isolated PR.

RESULTS

Here, 8991 patients were included and isolate PR occurred in 77 (0.9%) patients. The median time to PR was 16.2 months (intrquartile range = 9.3-28.0 months) and most patients were identified via new symptoms (36.4%). Pathologic factors associated with increased odds of PR included higher T stage (T3 vs. T2, odds ratio [OR] = 4.8, 95% confidence interval [CI] = 1.5-15.7), N stage (N1 vs. N0, OR = 2.00, CI = 1.1-3.7), and signet ring (OR = 8.2, CI = 3.0-22.3) or mucinous histology (OR = 2.6, CI = 1.5-4.7).

CONCLUSIONS

The majority of PR was detected within 18 months and few were identified by surveillance. Advanced T/N stage and signet ring/mucinous histology were associated with increased odds of PR.

Summary perioperative risk metrics within the electronic medical record predict patient-level cost variation in pancreaticoduodenectomy

BACKGROUND

Automated data extraction from the electronic medical record is fast, scalable, and inexpensive compared with manual abstraction. However, concerns regarding data quality and control for underlying patient variation when performing retrospective analyses exist. This study assesses the ability of summary electronic medical record metrics to control for patient-level variation in cost outcomes in pancreaticoduodenectomy.

METHODS

Patients that underwent pancreaticoduodenectomy from 2014 to 2018 at a single institution were identified within the electronic medical record and linked with the National Surgical Quality Improvement Program. Variables in both data sets were compared using interrater reliability. Logistic and linear regression modelling of complications and costs were performed using combinations of comorbidities/summary metrics. Models were compared using the adjusted R² and Akaike information criterion.

RESULTS

A total of 117 patients populated the final data set. A total of 31 (26.5%) patients experienced a complication identified by the National Surgical Quality Improvement Program. The median direct variable cost for the encounter was US$14,314. Agreement between variables present in the electronic medical record and the National Surgical Quality Improvement Program was excellent. Stepwise linear regression models of costs, using only electronic medical record-extractable variables, were non-inferior to those created with manually abstracted individual comorbidities (R² = 0.67 vs 0.30, Akaike information criterion 2,095 vs 2,216). Model performance statistics were minimally impacted by the addition of comorbidities to models containing electronic medical record summary metrics (R² = 0.67 vs 0.70, Akaike information criterion 2,095 vs 2,088).

CONCLUSION

Summary electronic medical record perioperative risk metrics predict patient-level cost variation as effectively as individual comorbidities in the pancreaticoduodenectomy population. Automated electronic medical record data extraction can expand the patient population available for retrospective analysis without the associated increase in human and fiscal resources that manual data abstraction requires.

Combining Immunotherapies with Conventional Cancer Therapies in a Preclinical Model of Treatment-Resistant, High-Risk Neuroblastoma

Patients diagnosed with neuroblastoma (NBL) are segmented into categories, with ~50% considered high-risk and ~40% of those patients eventually succumbing to disease. Our group published a regimen (“CAIR”) combining adaptive and innate immunotherapies with radiotherapy (RT) to treat an immunologically cold, treatment-resistant model of NBL (9464D-GD2). Despite CAIR being our most effective treatment, it only cures ~40% of tumors and lacks clinical relevance due in part to toxicities. Here we aimed to test if the clinically-approved salvage therapy of temozolomide and irinotecan (T/I) and αGD2-based therapy replicated human trials and to test if CAIR can be reduced to improve relevance.

For chemo studies, mice were treated T/I and αGD2 immunocytokine (Hu14.18-IL2). T/I or Hu14.18-IL2 alone did not extend survival of 9464D-GD2-bearing mice (p=0.596 and p&gt;0.999). T/I and Hu14.18-IL2 together extended survival (p=0.036 and p=0.004) but none of these treatments resulted in cures. To test CAIR reductions, mice were treated with RT, αCD40, αCTLA4, CpG, and Hu14.18-IL2. The full regimen cured 36% of mice (8/22), CAIR minus αCTLA cured 43% (9/21), CAIR minus αCD40 cured 50% (8/16), and CAIR minus CpG cured 44% (7/16). CAIR minus RT or Hu14.18-IL2 cured no mice (0/8 each).

Demonstrating similarity to human NBLs that do not respond to salvage treatment of T/I and αGD2 therapy, 9464D-GD2 tumors are not cured by T/I and αGD2 immunocytokine (Hu14.18-IL2). In contrast, CAIR can cure 9464D-GD2 bearing mice, and our data indicate that this regimen can be further reduced without decreasing efficacy. A reduced regimen enhances both clinical relevance and our ability to add additional agents to further improve survival.

Fellowship support provided by the Hartwell Foundation.

Abstract B36: Preclinical development of a multikinase targeting molecule with activity against the cancer stem cell phenotype in pancreatic adenocarcinoma

Background: Pancreatic cancer is highly resistant to existing chemotherapy regimens, with only a minority of patients exhibiting a response to standard therapy. One aspect of treatment resistance is based on the cancer stem cell (CSC) hypothesis, which holds that a small population of highly chemoresistant cells is responsible for initiating and sustaining tumor growth. Compounds with activity against this population are highly desired in the adjuvant setting, where failure to sterilize micrometastases not detected at time of operation results in recurrence in nearly all patients.

Methods: A high-throughput drug screen (HTS) was performed in an in vitro model of pancreatic cancer stem-like cells (spheroids). Molecules with high potency against both the cancer stem cell-like spheroid and monolayer cell formats were evaluated for efficacy and mechanism of action in a variety of preclinical models of pancreatic cancer. Unbiased global in situ phosphoproteomic profiling using KiNativ technology was used to identify kinase targets impacted by the top hit. Stemness phenotype was interrogated by qRT-PCR of stemness genes, flow cytometry, colony formation assays, and tumor initiation in immunocompromised mice.

Results: The top hit from the HTS was a 1H-benzo[d]imidazol-2-amine-based inhibitor of interleukin-2-inducible T-cell kinase (ITK) (NCGC00188382, 1). 1 effectively mediated growth inhibition, blocked migration and invasion, and reduced clonogenicity of cancer cells with an associated decrease in the expression of several CSC-associated stemness markers at non-lethal concentrations (Sox2, Notch1) compared to gemcitabine used at &gt;10-fold concentration. Metastatic burden in both the liver and lung was significantly reduced in mice orthotopically injected with pancreatic CSCs in the treatment group after 6 weeks.

Target deconvolution of 1 demonstrated inhibition of multiple select kinase targets. There were 16 targets identified from an initial screening panel of &gt;400 kinases. The targets were further evaluated for the ability to phenocopy the effect of treatment with 1 via shRNA knockdown. Inhibition of the thousand-and-one amino acid kinase 3 (TAOK3), cyclin-dependent kinase 7 (CDK7), aurora B kinase (AURKB), and ephrin B2 receptor (EPHB2) effectively phenocopied the effect of treatment with 1. Concurrent silencing of two or more targets increased apoptosis induced by 1, suggesting intrinsic additivity of the multikinase agent. Enforced overexpression of TAOK3 increased expression of stemness markers, clonogenicity, and tumor initiation in vivo.

Conclusion: A potent inhibitor of ITK with a unique target profile and anti-stemness activities was derived from a differential HTS in a pancreatic spheroid CSC model. The 1H-benzo[d]imidazol-2-amine-derivative targets select characteristics attributed to pancreatic CSCs, including cell migration, colony formation, and metastasis formation with concomitant suppression of stemness traits without inducing cell death at the concentrations used. Target deconvolution of the compound identified multiple kinase targets, including TAOK3, a kinase not previously known to be involved in pancreatic tumor biology. Overexpression of TAOK3 results in an enforced CSC phenotype including increased colony formation and tumor initiation in vivo. The observed inhibitory effect of 1 on stemness phenotype at nanomolar concentrations without affecting cell viability or showing toxicity in vivo supports further preclinical development.

Citation Format: Taylor Aiken, Yansong Bian, Yaroslav Teper, Lesley Mathews Griner, Rajarshi Guha, Paul Shinn, Hong-Wu Xin, Holger Pflicke, Jian-kang Jiang, Paresma Patel, Steven Rogers, Jeffery Aube, Marc Ferrer, Craig J. Thomas, Udo Rudloff.{Authors}. Preclinical development of a multikinase targeting molecule with activity against the cancer stem cell phenotype in pancreatic adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B36.

Abstract 1385: The influence of MHC class I and II on T cell responses in mouse melanoma

Introduction: Using an in situ vaccine (ISV) regimen consisting of radiation combined with immunocytokine (tumor-targeting mAb linked to IL2), we can cure mice of well established B78 melanoma tumors (B78s). Mice cured of their B78s with ISV demonstrate long-term immune memory, evidenced by rejection of engraftment of a tumor rechallenge &gt;180 days post initial cure of tumor. Traditionally, immaune memory is thought to be mediated via CD8+ T cells, which require antigen presentation via MHC Class I (MHCI). However, B78s express little to no MHCI but do express MHCII when stimulated with IFNγ. While not commonly expressed on solid tumors, MHCII is expressed on 50-60% of melanomas in humans. Here we explored implications of MHCI and MHCII expression in both the primary and long-term memory anti-tumor responses generated with ISV.

Methods: CD4+ or CD8+ T cells were depleted in mice during the primary anti-tumor response (i.e. B78 tumor bearing mice receiving the ISV regimen) or during tumor rechallenge experiments (i.e. B78-cured mice rechallenged with B78s). Tumor growth was monitored. In separate studies, tumors and tumor draining lymphnodes (TDLNs) were harvested during the primary antitumor response and analyzed via flow cytometry to assess T cell activation and immune infiltrate. Finally, TDLNs were harvested from B78-cured mice, 7 days after tumor rechallenge, to define memory T cell subsets.

Results: Depletion studies revealed CD4+ T cells are required for both the antitumor response to ISV and the long-term memory response in B78-cured mice, but CD8+ T cells are not required for either of these responses. Increased CD8+ and CD4+ T cell infiltrates are observed in the tumor microenvironment during the primary anti-tumor response. In B78-cured mice, though not required for memory responses, CD8+ central memory T cells are significantly increased in the TDLNs compared to naïve or primary tumor bearing mice. The amount of CD4+ effector memory T cells are significantly increased in the TDLN of B78-cured mice compared to CD8+ effector memory T cells.

Conclusion: Often not expressed on solid tumors, MHCII is expressed on some melanoma tumors, and its expression has been correlated with a positive response to immunotherapies. CD4+ cytotoxic T cells can directly engage MHCII on tumors, suggesting this interaction has an important role in the response to immunotherapy for MHCII expressing tumors. Our data suggest that CD4+ T cells drive both the primary anti-tumor and long-term immune memory responses in the B78 model when treating with this effective ISV. We are continuing our efforts to understand the characteristics of the B78 cell line that may be relevant to its response to immunotherapy and its resistance to single agent checkpoint blockade. Understanding the cellular and molecular mechanisms involved in ISV-induced immune recognition and destruction of B78s may guide future improvements of this clinically-relevant immunotherapy regimen.

Citation Format: Amy K. Erbe, Arika Feils, Mackenzie Heck, Sabrina VandenHeuvel, Julianna Castillo, Alina Hampton, Lizzie Frankel, Anna Hoefges, Peter Carlson, Alex A. Pieper, Taylor Aiken, Lauren Zebertavage, David Komjathy, Dan Spiegelman, Noah Tsarovsky, Zachary S. Morris, Ravi Patel, Alexander Rakhmilevich, Paul M. Sondel. The influence of MHC class I and II on T cell responses in mouse melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1385.