Abstract P3-16-02: Nanotheranostics using plasmonic gold nanostars to target inflammatory breast cancer cells and tumor emboli

Introduction: Due to the aggressive nature of inflammatory breast cancer (IBC) and insensitive imaging techniques, patients diagnosed with IBC have a poor prognosis. IBC's unique ability to form emboli leads to rapid growth and distant invasion. New therapies aimed at disrupting the formation of tumor emboli are needed. Gold nanostars (GNS) are unique nanoparticles that can be imaged in real time with high sensitivity, and are rapidly endocytosed into cancer cells. Due to their sharp spikes, GNS exhibit plasmonic properties, which strongly enhance the electromagnetic field upon laser excitation. In addition to their use as highly intense and stable fluorescent labels, these nanoparticles can be photothermally activated to trigger cellular ablation. The use of GNS as an imaging and therapeutic modality for IBC should be investigated.

Methods: IBC (SUM-149/SUM190), non-IBC (BT474M1/MD-MBA-231), and drug resistant isotype variant (rSUM-149) cell lines were incubated with GNS, stained with Hoechst33342, and imaged with multiphoton microscopy (MPM). The dose and time dependent effects of GNS on SUM-149 proliferation was assessed with MTT assays. Photothermal treatment was performed on GNS-labeled IBC, non-IBC, and drug resistant cancer cell lines. The effects of photothermal therapy on cell viability were assessed using fluorescein diacetate and propidium iodide. Using a tumor emboli model, SUM-149, rSUM-149, and SUM-190 tumor emboli were labeled with GNS on the 3rd day of embolic maturation. Emboli were sectioned, stained with H/E, and imaged with MPM to demonstrate the depth of GNS penetrance. The potential for photothermal ablation of the GNS-labeled tumor emboli was assessed using various laser intensities. Propidium iodide was used to examine emboli viability following treatment.

Results: In all cell lines, GNS displayed rapid cellular uptake without nuclear involvement. MTT assay showed that GNS concentrations of 0.15 and 0.20 nM caused decreases in cell proliferation at 6 and 12 hours. Proliferative capacity was unaltered at 24 hours for all concentrations, however this may be due to spectrophotometric interference with high intracellular GNS concentrations. Live/dead staining confirmed effective photothermal treatment in all cultures with a clear zone of cellular death. For tumor emboli studies, GNS allowed bright fluorescent monitoring of tumor emboli using MPM, and cross sectional imaging demonstrated GNS penetrance into the embolic core. Photothermal ablation of GNS-labeled tumor emboli was successfully demonstrated following laser irradiation. Cell death was confirmed with propidium iodide.

Conclusion: Gold nanostars provide a highly fluorescent intracellular label for cancer cell lines, and tumor emboli without significantly altering cell proliferation. Furthermore, the inherent optical properties of the GNS allows for a combined therapeutic application following phototoactivation. This is the first study to demonstrate the nanothernostic application of GNS in IBC tumor emboli. Prior studies have shown the effectiveness of photothermal ablation in in vivo sarcoma models; we are currently extending our studies to an IBC mouse model.

Supported by the P30 Cancer Center Support Grant (GRD) and Duke Exploratory Funds (TVD).

Citation Format: Shammas RL, Fales AM, Crawford BM, Hollenbeck ST, Vo-Dinh T, Devi GR. Nanotheranostics using plasmonic gold nanostars to target inflammatory breast cancer cells and tumor emboli [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-16-02.

Use of vascularized posterior rectus sheath allograft in pediatric multivisceral transplantation--report of two cases

Restoring abdominal wall cover and contour in children undergoing bowel and multivisceral transplantation is often challenging due to discrepancy in size between donor and recipient, poor musculature related to birth defects and loss of abdominal wall integrity from multiple surgeries. A recent innovation is the use of vascularized posterior rectus sheath to enable closure of abdomen. We describe the application of this technique in two pediatric multivisceral transplant recipients--one to buttress a lax abdominal wall in a 22-month-old child with megacystis microcolon intestinal hypoperistalsis syndrome and another to accommodate transplanted viscera in a 10-month child with short bowel secondary to gastoschisis and loss of domain. This is the first successful report of this procedure with long-term survival. The procedure has potential application to facilitate difficult abdominal closure in both adults and pediatric liver and multivisceral transplantation.

[Femur reconstruction using combined autologous fibula transfer and humeral allograft]

Wide resection far into the femoral metaphysis may be required to treat malignant bone tumors in the pediatric and adolescent patient population. Biological reconstruction using a free, vascularized fibular graft is a well-established surgical technique. A short remaining femoral medullary canal and a relatively small fibula diameter can make fixation of the vascularized bone transfer difficult. Stable fixation and short fusion times, however, can be achieved with the use of an additional humeral allograft and plate osteosynthesis.

Factors Associated With Residual Breast Cancer After Re-excision for Close or Positive Margins

BACKGROUND

Successful breast conservation surgery (BCS) requires complete tumor excision. Margin status of the initial specimen determines the need for additional surgery. We explored factors associated with residual cancer (RC) upon follow-up surgery in patients with close, positive, or undetermined margins following BCS.

METHODS

A retrospective analysis of 276 patients with initial close, positive, or undetermined margins who underwent re-excision (RE) or mastectomy was conducted. All initial excisions were intended as definitive procedures. Chi-square analysis was used to identify factors that may predict RC.

RESULTS

Of 276 patients, 87 had close, 168 had positive, and 21 had undetermined margins on initial excision. Of this group, 63% (175/276) had RC upon RE or mastectomy. Of positive-margin patients, 68% had RC, compared with 53% of close-margin and 67% of undetermined-margin patients (P = .006). Tumors >/=2 cm were more often associated with RC than smaller tumors (70.8% vs. 56.5%; P = .07). This association was strongest in positive-margin patients (P = .04). High tumor grade was associated with RC in all groups. RC linearly increased with the number of involved margins (P = .02). Specimen inking with multiple colors was associated with decreased risk of RC (P = .004).

CONCLUSIONS

Over half of patients with involved or undetermined margins had RC upon RE or mastectomy. Positive and undetermined margins were more often associated with RC than close margins. Larger tumor size was associated with RC in patients with positive. Increasing tumor grade suggests a greater chance of detecting RC in all groups. Multiple involved margins led to a greater risk of RC.

Breast cancer in patients with residual invasive carcinoma is more accurately staged with additive tumor size assessment

BACKGROUND

Accurate assessment of tumor size for patients with breast cancer undergoing re-excision following breast-conserving therapy is important for appropriate staging and adjuvant treatment. We investigated the accuracy of additive vs. nonadditive size assessment in determining final tumor stage.

METHODS

Patients with infiltrating carcinoma in the initial excision and in at least one additional re-excision (re-excision positive; n = 89) had tumor size assessed with additive and nonadditive techniques. This group was compared with patients undergoing re-excision but without identifiable residual carcinoma (re-excision negative; n = 105) regarding rates of lymph node (LN) metastasis.

RESULTS

The re-excision positive patients had a different median final tumor size depending on the size assessment technique used (nonadditive: 1.8 cm; additive: 3.0 cm; P <.0001). Both groups of patients had a median tumor size consistent with T1c staging in nonadditive size assessment. However, re-excision positive patients had a significantly higher incidence of LN metastasis (P <.05) than did re-excision negative patients. Both groups were then separated into T1 and T2 stages and the LN metastasis rates were assessed. Compared with nonadditive size assessment, additive size assessment distributed re-excision positive patients into T stages whereby the LN metastasis rates more closely approximated those of re-excision negative patients (T1, 3% vs. 6% difference; T2, 4% vs. 13% difference).

CONCLUSIONS

With regard to LN metastasis, staging for patients with residual invasive carcinoma in re-excision specimens is more accurate with additive tumor size assessment.