Nobutaka Iwakuma

Gold nanoparticles as a contrast agent for in vivo tumor imaging with photoacoustic tomography

Photoacoustic tomography (PAT) is a rapidly emerging non-invasive imaging technology that integrates the merits of high optical contrast with high ultrasound resolution. The ability to quantitatively and non-invasively image nanoparticles has important implications for the development of nanoparticles as in vivo cancer diagnostic and therapeutic agents. In this study, the ability of systemically administered poly(ethylene glycol)-coated (PEGylated) gold nanoparticles as a contrast agent for in vivo tumor imaging with PAT has been evaluated. We demonstrate that gold nanoparticles (20 and 50 nm) have high photoacoustic contrast as compared to mouse tissue ex vivo. Gold nanoparticles can be visualized in mice in vivo following subcutaneous administration using PAT. Following intravenous administration of PEGylated gold nanoparticles to tumor-bearing mice, accumulation of gold nanoparticles in tumors can be effectively imaged with PAT. With gold nanoparticles as a contrast agent, PAT has important potential applications in the image guided therapy of superficial tumors such as breast cancer, melanoma and Merkel cell carcinoma.

Polyhydroxy fullerenes for non-invasive cancer imaging and therapy.

DOI: 10.1002/smll.201000847 Nanoparticle-mediated, image-guided cancer therapy has tremendous promise for increasing the effi cacy of cancer treatment while reducing toxic side effects traditionally associated with treatment. Carbon nanotubes and metal-based nanomaterials are leading candidates for image-guided therapy in cancer nanotechnology. [ 1–5 ] However, limited solvent compatibility, non-biodegradability and concerns over the safety of these nanomaterials may hinder their commercialization. Here, we show that the photothermal and photoacoustic properties of polyhydroxy fullerenes [ 6 ] (PHF)—which are water-soluble, biodegradable, [ 7 ] antioxidant, [ 8–10 ] and rapidly excreted [ 11 ] —can be applied for imaging and therapy of cancer. Biodegradable PHF-containing chitosan nanoparticles provided excellent photoacoustic contrast. Tumors injected with PHF nanoparticles and exposed to near infrared laser decreased in cross-sectional area by an average of 32% within two hours of treatment, with only a blister visible 20 hours post-treatment. We anticipate that photoacoustic and photothermal properties of PHF along with their other therapeutic properties [ 12–15 ] will enable safe, non-invasive image-guided therapy of cancer with minimal side-effects. Polyhydroxy Fullerenes for Non-Invasive Cancer Imaging and Therapy

Gadolinium‐Doped Silica Nanoparticles Encapsulating Indocyanine Green for Near Infrared and Magnetic Resonance Imaging

Clinical applications of the indocyanine green (ICG) dye, the only near infrared (NIR) imaging dye approved by the Food and Drug Administration (FDA) in the USA, are limited due to rapid protein binding, fast clearance, and instability in physiologically relevant conditions. Encapsulating ICG in silica particles can enhance its photostability, minimize photobleaching, increase the signal-to-noise (S/N) ratio and enable in vivo studies. Furthermore, a combined magnetic resonance (MR) and NIR imaging particulate can integrate the advantage of high-resolution 3D anatomical imaging with high-sensitivity deep-tissue in-vivo fluorescent imaging. In this report, a novel synthesis technique that can achieve these goals is presented. A reverse-microemulsion-based synthesis protocol is employed to produce 25 nm ICG-doped silica nanoparticles (NPs). The encapsulation of ICG is achieved by manipulating coulombic attractions with bivalent ions and aminated silanes and carrying out silica synthesis in salt-catalyzed, mildly basic pH conditions using dioctyl sulfosuccinate (AOT)/heptane/water microemulsion system. Furthermore, paramagnetic properties are imparted by chelating paramagnetic Gd to the ICG-doped silica NPs. Aqueous ICG-dye-doped silica NPs show increased photostability (over a week) and minimal photobleaching as compared to the dye alone. The MR and optical imaging capabilities of these particles are demonstrated through phantom, in vitro and in vivo experiments. The described particles have the potential to act as theranostic agents by combining photodynamic therapy through the absorption of NIR irradiated light.

FOXP3 expression in tumor cells and tumor-infiltrating lymphocytes is associated with breast cancer prognosis

The forkhead box protein 3 (FOXP3) transcription factor is highly expressed in tumor cells as well as in regulatory T cells (Tregs). It plays a tumor-enhancing role in Tregs and suppresses carcinogenesis as a potent repressor of several oncogenes. The clinical prognostic value of FOXP3 expression has not yet been elucidated. In this study, immunohistochemistry was used to investigate the prognostic significance of FOXP3 expression in tumor cells and tumor-infiltrating lymphocytes (TILs) in breast cancer patients. Of the 100 tumor specimens obtained from primary invasive breast carcinoma, 63 and 57% were evaluated as FOXP3+ tumor cells and as being highly infiltrated by FOXP3+ lymphocytes, respectively. Although FOXP3 expression in tumor cells was of no prognostic significance, FOXP3+ lymphocytes were significantly associated with poor overall survival (OS) (n=98, log-rank test P=0.008). FOXP3 exhibited a heterogeneous subcellular localization in tumor cells (cytoplasm, 31%; nucleus, 26%; both, 6%) and, although cytoplasmic FOXP3 was associated with poor OS (P= 0.058), nuclear FOXP3 demonstrated a significant association with improved OS (P=0.016). Furthermore, when patients were grouped according to their expression of tumor cytoplasmic FOXP3 and lymphocyte FOXP3, there were notable differences in the Kaplan-Meier curves for OS (P<0.001), with a high infiltration of FOXP3+ lymphocytes accompanied by a cytoplasmic FOXP3+ tumor being the most detrimental phenotype. These findings indicated that FOXP3 expression in lymphocytes as well as in tumor cells may be a prognostic marker for breast cancer. FOXP3 in tumor cells may have distinct biological activities and prognostic values according to its localization, which may help establish appropriate cancer treatments.

Nanoparticle delivery for metastatic breast cancer

Breast cancer represents a major ongoing public health problem as the most common non-cutaneous malignancy among U.S. women. While significant progress has been made in improving loco-regional treatments for breast cancer, relatively little progress has been made in diagnosing and treating patients with metastatic breast cancer. At present there are limited curative options for patients with breast cancer metastatic beyond regional nodes. Emerging nanotechnologies promise new approaches to early detection and treatment of metastatic breast cancer. Fulfilling the promise of nanotechnologies for patients with metastatic breast cancer will require delivery of nanomaterials to sites of metastatic disease. Future translational approaches will rely on an ever increasing understanding of the biology of breast cancer subtypes and their metastases. These important concepts will be highlighted and elucidated in this manuscript.

What Is Cancer Nanotechnology

Cancer nanotechnology has the potential to dramatically improve current approaches to cancer detection, diagnosis, imaging, and therapy while reducing toxicity associated with traditional cancer therapy (1, 2). In this overview, we will define cancer nanotechnology, consider issues related to application of nanotechnology for cancer imaging and therapy, and broadly consider implications for continued development in nanotechnology for the future of clinical cancer care. These considerations will place in perspective the methodological approaches in cancer nanotechnology and subject reviews outlined in this volume.

Nanoparticle delivery for metastatic breast cancer.

Breast cancer represents a major ongoing public health problem as the most common non-cutaneous malignancy among U.S. women. While significant progress has been made in improving loco-regional treatments for breast cancer, relatively little progress has been made in diagnosing and treating patients with metastatic breast cancer. At present there are limited curative options for patients with breast cancer metastatic beyond regional nodes. Emerging nanotechnologies promise new approaches to early detection and treatment of metastatic breast cancer. Fulfilling the promise of nanotechnologies for patients with metastatic breast cancer will require delivery of nanomaterials to sites of metastatic disease. Future translational approaches will rely on an ever increasing understanding of the biology of breast cancer subtypes and their metastases. These important concepts will be highlighted and elucidated in this manuscript.

Predictive factors of the tumor immunological microenvironment for long-term follow-up in early stage breast cancer

The aim of this research was to investigate the correlation of immunologic factors in the tumor environment of breast cancer, using immunohistological staining to evaluate the expression of programmed death 1/programmed death ligand 1 (PD‐1/PD‐L1), phosphatase and tensin homolog (PTEN), tumor infiltrating lymphocytes (TILs), and macrophages, and to analyze the association between the immunologic factors and clinical outcome for patients with early stage breast cancer (EBC). A total of 97 EBC patients who underwent standard surgery were investigated. Expression of PD‐1/PD‐L1 and PTEN and the density of CD3+ TILs, CD8+ TILs, and CD163+ macrophages were evaluated by immunohistochemical analysis. The association between the immunologic factors and clinical outcome was statistically analyzed. The density of CD3+ TILs, CD8+ TILs, and CD163+ macrophages and non‐expression of PTEN was significantly higher in cases of triple negative breast cancer. CD8+ TIL density and CD8+/PD‐L1+ expression were predictive factors for disease‐free survival and overall survival (OS). Human epidermal growth factor 2 (HER2)‐positive patients with PTEN expression and luminal/HER2‐negative patients without PD‐L1 expression had significantly longer OS compared to patients without PTEN expression (P = 0.049) and with PD‐L1 expression (P = 0.036), respectively. Furthermore, patients with PD‐L1+/CD8+ expression had worse median progression‐free survival (P = 0.022) and median OS (P = 0.037) compared with patients without PD‐L1+/CD8+ expression. The CD3+ TILs, CD8+ TILs, and CD163+ macrophages were shown to infiltrate the tumor area of EBC. In particular, triple negative breast cancer had a higher rate of TIL infiltration within the tumor environment. Expression of PTEN and lack of PD‐L1 expression were associated with favorable survival in HER2‐positive and luminal/HER2‐negative EBC patients, respectively. The PD‐L1 expression combined with CD8+ density was significantly associated with an aggressive clinical outcome.

Usefulness of endoscopic breast-conserving surgery for breast cancer

PurposeWe compared the safety, invasiveness and cosmetic outcomes between endoscopic breast-conserving surgery (endoscopic group) and surgery under direct vision (direct vision group) for treating breast cancer.MethodsWe compared 100 cases of endoscopic surgery with 150 cases of direct vision surgery. The safety was evaluated in terms of the blood loss, length of the operation and presence or absence of complications, whereas the degree of invasiveness was assessed using preoperative and postoperative leukocyte counts, neutrophil counts, interleukin (IL-6) levels and fever. The cosmetic outcome was assessed on the basis of a breast evaluation by the medical staff and the patient’s subjective satisfaction.ResultsIn both groups, serious postoperative complications were absent. No significant differences were observed in the leukocyte counts, neutrophil counts, IL-6 level or fever between the groups. An evaluation of the cosmetic outcomes by the staff showed a more favorable breast size, breast shape and scar condition in the endoscopic group. A significantly higher level of patient satisfaction was also observed in the endoscopic group. Postoperative local recurrence was absent.ConclusionsThe endoscopic approach showed comparable safety and invasiveness, and provided better postoperative cosmetic outcomes than direct vision surgery. Our results suggest that endoscopic breast-conserving surgery is a potentially useful surgical method for the treatment of breast cancer.

Methotrexate (MTX)-associated malignant lymphoma of the bilateral breast: imaging features in comparison to other nipple-areolar tumors

Tumors originating from the nipple-areolar complex of the breast are rare. We herein report the case of a patient with metachronous bilateral areolar methotrexate (MTX)-associated lymphoma. The patient was a 67-year-old woman who presented with a rapidly enlarging tumor in the areolar region of her left breast. She had a long history of rheumatoid arthritis and had taken MTX for many years. On ultrasonography, the tumor showed well-demarcated margins and hyper-vascularity. On magnetic resonance imaging, the tumor showed a homogeneous low-to-moderate signal intensity that was similar to that of the nipple on both T1- and T2-weighted imaging; the diffusion was significantly reduced on diffusion-weighted images. The tumor showed a medium-plateau pattern on dynamic contrast-enhanced imaging. No necrotic change was observed. Based on the imaging findings, we considered the tumor to have originated from the areola. According to the internal homogeneity, the rapid growth and hyper-cellularity, the potential diagnoses included a small round cell tumor (including malignant lymphoma) and a mesenchymal neoplasm (especially leiomyoma or leiomyosarcoma, which frequently originate from the areolar region). An excisional biopsy of the tumor was performed. The pathological diagnosis was diffuse large, non GC B-cell lymphoma that we suspected was associated with MTX. The tumor shrank rapidly after the withdrawal of MTX. After three months, we detected a B-cell lymphoma of the same type originating in the contralateral areola. We compared the characteristics of the imaging findings of the MTX-associated lymphoma with the nipple-areolar or periareolar tumors and primary breast lymphoma.