Osteomimetic matrix components alter cell migration and drug response in a 3D tumour-engineered osteosarcoma model

Osteosarcoma management continues to lack the appropriate prognostic tools to assign personalised treatment. This leaves non-responders to standard care vulnerable to recurring disease and pulmonary metastases. Developing 3D in vitro disease models to serve as a test bed for personalised treatment is a promising approach to address this issue. This study describes the generation of 3D osteosarcoma models termed "tumouroids", which are geometrically compartmentalised to reproduce the bone cancer mass and its surrounding. Although the tumour microenvironment impacts osteosarcoma in many ways, this model focussed on interrogating the influence of a biomimetic matrix on tumour cell behaviour. The 3D matrix was supplemented with the bone-marrow proteins laminin, fibronectin and NuOss® bone granules. This led to increased invasion of osteosarcoma cell aggregates from within the bone-like matrix into the surrounding acellular bone marrow-like ECM. The presence of bone granules also yielded an atypical molecular profile of osteosarcoma cells, suggesting malignant metabolic reprogramming. Changes include decreased MMP-9 (p < 0.05) and increased PTEN (p < 0.05), MCP-1 (p < 0.01) and MCT-4 (p < 0.05) gene expression. This complex 3D biomimetic composition also changed cellular responses to doxorubicin, a common chemotherapeutic agent used to treat osteosarcoma, and reproduced key issues of in vivo treatment like drug penetrance and doxorubicin-induced bone toxicity. This work highlights the importance of a biomimetic matrix in 3D osteosarcoma models for both basic and translational research. STATEMENT OF SIGNIFICANCE: This study describes the generation of 3D osteosarcoma models termed "tumouroids", which are geometrically compartmentalised to reproduce the bone cancer mass and its environment. Utilising this novel model, specific parameters of osteosarcoma growth and invasion were investigated. Osteosarcoma cell lines proliferate at a slower rate, exhibit malignant metabolic reprogramming, and respond to drug intervention at lower concentrations of doxorubicin hydrochloride in matrix-complex compared to basic tumouroids. As such, this study provides evidence that the tumour microenvironment impacts osteosarcoma in many ways. The osteosarcoma tumouroid described herein may form the basis of a personalised-medicine strategy, which will allow the testing of drug effectiveness similar to that used for antibiotic selection for pathogenic bacteria.

Breast deformation during the course of radiotherapy: The need for an additional outer margin

PURPOSE

The aim of this retrospective study was to investigate and quantify the extent of breast deformation during the course of breast cancer (BC) radiotherapy (RT). The magnitude of breast deformation determines the additional outer margin needed for treatment planning to deliver a full dose to the target volume. This is especially important when using inverse planning techniques.

METHODS

A total of 93 BC patients treated with RT and with daily CBCT image guidance were selected for this study. Patients underwent either only breast-conserving surgery (BCS) (n = 5), BCS with sentinel node biopsy (n = 57) or BCS with radical axillary node dissection (n = 31). The treatment area included the whole breast and chest wall (54%) or also the axillary lymph nodes (46%). 3D-registration was conducted between 1731 CBCT images and the respective planning CT images to assess the difference in breast surface.

RESULTS

The largest maximum breast surface expansion (MBSE) was 15 mm; the average was 2.4 ± 2.1 mm. In 294 fractions (17%), the MBSE was ≥5 mm. An outer margin of 8 mm would have been required to cover the whole breast in 95% of the treated fractions. There was a statistically significant correlation between the MBSE and body mass index (r = 0.38, p = 0.001).

CONCLUSIONS

Significant changes in the breast surface occur during the course of BC RT which should be considered in treatment planning. An additional margin outside the breast surface of at least 8 mm is required to take into account the anatomical changes occurring during BC RT.

Impact of surgical approach on short-term oncological outcomes and recovery following low anterior resection for rectal cancer

AIM

The aim was to evaluate the influence of operative approach for low anterior resection (LAR) on oncological and postoperative outcomes. Minimally invasive surgical approaches are increasingly used for the treatment of rectal cancer with mixed outcomes.

METHOD

We compared patients undergoing LAR in the National Cancer Database between 2010 and 2015 by surgical approach. Multivariable regression was used to identify risk factors associated with conversion rate, prolonged length of stay (LOS) and 30-day unplanned readmission.

RESULTS

During the study period, 41 282 patients underwent LAR: 6035 robotic-assisted (RLAR) (14.6%), 13 826 laparoscopic (LLAR) (33.5%) and 21 421 open (OLAR) (51.9%). In propensity score matched analysis, RLAR compared to LLAR was associated with shorter LOS (6.3 vs 6.8 days, P < 0.0001), lower risk of prolonged LOS (22.1% vs 25.6%, P < 0.0001) and lower rate of conversion to open (7.5% vs 14.95%, P < 0.0001). Compared to OLAR, RLAR had shorter LOS (6.3 vs 7.8 days, P < 0.0001) and less prolonged LOS (14.1% vs. 20.9%, P < 0.0001). In multivariable analysis, for conversion to open, the laparoscopic approach was one of the risk factors; for prolonged LOS, conversion to open and non-robotic approaches (i.e. LLAR and OLAR) were risk factors; and for unplanned 30-day readmission, conversions and prolonged LOS were risk factors.

CONCLUSIONS

For patients with rectal cancer, RLAR shows recovery benefits over both open and laparoscopic LAR with reduced conversion to open compared with LLAR and less prolonged LOS compared with LLAR and OLAR. RLAR is associated with short-term oncological outcomes comparable to OLAR, supporting its use in minimally invasive surgery for rectal cancer.

Abstract P4-01-16: Detection of plasma tumor DNA (ptDNA) in patients with hormone receptor-positive HER2-negative (HR+HER2-) early breast cancer (EBC) in clinical remission

Background: Detection of ptDNA in patients with HR+HER2- EBC in clinical remission may impact recommendations for type and duration of adjuvant endocrine therapy. A sensitive technique to identify tumor mutations in plasma is BEAMing digital PCR. The frequency and timing of detectable mutations in plasma of patients in clinical remission from HR+HER2- EBC are unknown.

Methods: We screened a prospective institutional repository for patients that met inclusion criteria. Eligible patients must have been enrolled to the repository between 12/1/2008 (repository start) and 12/31/2016, had HR+HER2- EBC, received follow-up at Johns Hopkins with appointment scheduled between 3/1/2017 and 12/31/2017, completed curative surgery at least 6 months prior to this appointment, been recommended or initiated adjuvant endocrine therapy, and been in clinical remission. Appropriate patients were approached for a current blood sample during their follow-up appointment in 2017. Blood was analyzed using a BEAMing digital PCR platform (Sysmex Inostics OncoBEAM™) for AKT1, PIK3CA, and ESR1 mutations.

Results: We identified 67 eligible patients and collected blood from 60. Most patients had relatively low risk disease including 40 patients (67%) with stage I disease, and only 21 patients (35%) received chemotherapy. Patients were evenly divided between receiving tamoxifen or an aromatase inhibitor, and some patients switched from one to the other. The majority of patients (68%) had surgery between 1 and 5 years prior to the current blood draw. Detailed patient characteristics are provided in Table 1.

Two out of the 60 patients had detectable ptDNA, both with stage IIA disease. One patient had a mutation in the ESR1 ligand-binding domain P535H 9 months after surgery and while taking adjuvant tamoxifen for 7 months. Sanger sequencing of primary tumor tissue did not reveal this mutation. Another patient had a mutation in PIK3CA exon 9 E542K 9.5 years after surgery and after taking adjuvant tamoxifen for at least 7 years. Amplifying this locus in DNA from primary tumor tissue was unsuccessful; further analysis using droplet digital PCR (ddPCR) is planned.

Conclusions: Detection of ptDNA was feasible in a relatively low-risk group of patients with HR+HER2- EBC in clinical remission. Sampling a larger number of patients is needed to gain more understanding of the frequency and timing of detectable ptDNA. Next steps should also focus on determining the natural history of detectable ptDNA in patients with HR+HER2 EBC in clinical remission which may impact adjuvant treatment recommendations.

Funding sources: Komen SAC110053, P30 CA06973, Breast Cancer Research Foundation

Table 1:Characteristics of included patients N (%)Total patients60Age at diagnosis, median(range)57 (30-77)Female59 (98)Caucasian54 (90)Postmenopausal at diagnosis36 (60)Tumor size &lt;2 cm42 (70)Node negative45 (75)Invasive ductal histology44 (73)Received adjuvant chemotherapy21 (35)Type of adjuvant endocrine therapy Tamoxifen25 (42)Aromatase inhibitor26 (43)Tamoxifen and AI7 (12)None2 (3)Time after surgery 6 months to &lt;1 year6 (10)1 year to &lt;5 years41 (68)5 years to &lt;10 years13 (22)

Citation Format: Shah M, Hunter N, Ensminger J, Shinn D, Cole AJ, Quinn HE, Edelstein DL, Wang C, Smith KL, Richardson AL, Cimino-Mathews A, Wolff AC, Cravero K, Park BH, Stearns V. Detection of plasma tumor DNA (ptDNA) in patients with hormone receptor-positive HER2-negative (HR+HER2-) early breast cancer (EBC) in clinical remission [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-16.

Abstract P2-09-12: Perilymphatic IRX-2 cytokine therapy to enhance tumor infiltrating lymphocytes (TILs) and PD-L1 expression preceding curative-intent therapy in early stage breast cancer (ESBC)

Background: Cytokines are being explored as a therapeutic strategy to modulate the tumor microenvironment and facilitate immunotherapy benefit in breast cancer. Here, we investigate a locoregional therapeutic approach whereby cytokines (IRX-2) are administered into the subcutaneous peri-areolar tissue (in an anatomic distribution similar to sentinel lymph node mapping) to facilitate immune cell recruitment/activation within the draining lymph nodes and tumor in ESBC. IRX-2 is derived from ex vivo phytohemagglutinin-stimulated lymphocytes and contains multiple cytokines including IL-1β, IL-2, TNF-α, IFN-γ, IL-6, IL-8, and GM-CSF, with stable concentrations from lot to lot. Preclinically, IRX-2 activates T-cells and natural killer (NK) cells, facilitates antigen presentation, and enhances activity of anti-PD-1/L1 in a SCC7 model. In a preceding head/neck squamous cell carcinoma phase I trial, perilymphatic IRX-2 was safe and increased TILs. Here, we report the final clinical results of a phase Ib trial evaluating the feasibility and immunologic activity of IRX-2 in ESBC.

Methods: Beginning 21 days prior to surgical resection, enrolled operable patients with stage I-III ESBC (all subtypes) received the pre-operative IRX-2 regimen consisting of a single low-dose cyclophosphamide (300 mg/m2 to facilitate T-regulatory cell depletion), followed by 10 days of subcutaneous peri-areolar IRX-2 injections into the affected breast (1 mL × 2 at tumor axis and at 90°). Endpoints were feasibility (primary endpoint), stromal TIL (sTIL) count (pre-treatment versus post-treatment, blinded average of two pathologist reads using San Antonio H&E sTIL guidelines), PD-L1 expression (Nanostring) and enumeration of peripheral immune cells by flow cytometry.

Results: All patients (n=16/16) completed and tolerated the regimen with no surgical delays or treatment-attributed grade III/IV toxicities. Common adverse events (occurring in &gt;15% subjects) attributed to IRX-2 injections were: injection site reaction (grade 1, n=8/16), bruising (grade 1, n=7/16), and pain (grade 1, n=3/16). Common adverse events attributed to low-dose cyclophosphamide were: fatigue (grade 1, n=5/16) and nausea (grade 1/2, n=3/16). Treatment was associated with an increase in sTIL score (Wilcoxon signed-rank p=.04), with 4/10 sTIL-low tumors (0-10% score) re-categorized to sTIL-moderate (11-50% score). Increases in PD-L1 RNA expression were observed (Wilcoxon signed-rank p=.04) in 12/16 tumors (median 57% increase, range: -53% to 185% increase), as well as increases in Nanostring NK and Th1 cell signatures. In blood, increases in CD4 and CD8 effector T-cell activation (ICOS, HLA-DR, and CD38) and T-reg depletion were observed.

Conclusions: IRX-2 was well tolerated with preliminary evidence of sTIL increase, PD-L1 upregulation, and peripheral lymphocyte activation. Based upon these data and preclinical evaluations demonstrating synergy with checkpoint inhibition, the IRX-2 regimen is being evaluated for clinical efficacy in conjunction with pembrolizumab and neoadjuvant chemotherapy (doxorubicin, cyclophosphamide, paclitaxel) in patients with stage II-III triple negative breast cancer.

Citation Format: Pucilowska J, Egan JE, Berinstein NL, Moxon N, Aliabadi-Wahle S, Imatani JH, Conlin A, Acheson A, Massimino K, Martel M, Campbell M, Wu Y, Sun Z, Redmond W, Shah M, Urba WJ, Page DB. Perilymphatic IRX-2 cytokine therapy to enhance tumor infiltrating lymphocytes (TILs) and PD-L1 expression preceding curative-intent therapy in early stage breast cancer (ESBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-12.

Plasma Fibrinopeptide A and Beta-Thromboglobulin in Pre-Eclampsia and Pregnancy Hypertension

Increased plasma levels of β-thromboglobulin (βTG) and fibrinopeptide A (FPA), markers of platelet release and thrombin generation respectively, were measured in normal women, women taking oral contraceptives, normal pregnancy and pregnant women with hypertension or pre-eclampsia. No significant increases in βTG or FPA were found in women taking oral contraceptives. Significantly increased concentrations of βTG, but not FPA, were found in normal pregnant women in the second and third trimester of pregnancy when compared with nonpregnant age-matched controls. In eleven women with pregnancy hypertension and thirteen women with pre-eclampsia significantly elevated levels of both βTG and FPA were found when compared with age, parity and gestation-matched pregnant controls. Although the mean value for both βTG and FPA in the group with pre-eclampsia was higher than the group with pregnancy hypertension, the difference was not statistically significant. These findings provide additional evidence that pre-eclampsia and pregnancy hypertension are associated with activation of the coagulation system and the platelet release reaction.