Summary The Twist1 transcription factor is known to promote tumor metastasis and induce Epithelial-Mesenchymal Transition (EMT). Here, we report that Twist1 is capable of promoting the formation of invadopodia, specialized membrane protrusions for extracellular matrix degradation. Twist1 induces PDGFRα expression, which in turn activates Src, to promote invadopodia formation. We show that Twist1 and PDGFRα are central mediators of invadopodia formation in response to various EMT-inducing signals. Induction of PDGFRα and invadopodia is essential for Twist1 to promote tumor metastasis. Consistent with PDGFRα being a direct transcriptional target of Twist1, coexpression of Twist1 and PDGFRα predicts poor survival in breast tumor patients. Therefore, invadopodia-mediated matrix degradation is a key function of Twist1 in promoting tumor metastasis.

Methionine dependence is due to the overuse of methionine for aberrant transmethylation reactions in cancer. Methionine dependence may be the only general metabolic defect in cancer. In order to exploit methionine dependence for therapy, our laboratory previously cloned L-methionine α-deamino-γ-mercaptomethane lyase [EC 4.4.1.11]). The cloned methioninase, termed recombinant methioninase, or rMETase, has been tested in mouse models of human cancer cell lines. Ewing's sarcoma is recalcitrant disease even though development of multimodal therapy has improved patients'outcome. Here we report efficacy of rMETase against Ewing's sarcoma in a patient-derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma was implanted in the right chest wall of nude mice to establish a PDOX model. Eight Ewing's sarcoma PDOX mice were randomized into untreated control group (n = 4) and rMETase treatment group (n = 4). rMETase (100 units) was injected intraperitoneally (i.p.) every 24 hours for 14 consecutive days. All mice were sacrificed on day-15, 24 hours after the last rMETase administration. rMETase effectively reduced tumor growth compared to untreated control. The methionine level both of plasma and supernatants derived from sonicated tumors was lower in the rMETase group. Body weight did not significantly differ at any time points between the 2 groups. The present study is the first demonstrating rMETase efficacy in a PDOX model, suggesting potential clinical development, especially in recalcitrant cancers such as Ewing's sarcoma.

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Objective: To determine if intraoperative near-infrared (NIR) imaging carries benefit in resection of pancreatic neoplasms. Background: Resection of pancreatic malignancies is hindered by high rates of local and distant recurrence from positive margins and unrecognized metastases. Improved tumor visualization could improve outcomes. We hypothesized that intraoperative NIR imaging with a clinically approved optical contrast agent could serve as a useful adjunct in assessing margins and extent of disease during pancreatic resections. Methods: Twenty patients were enrolled in an open-label clinical trial from July 2016 to May 2018. Subjects received second window indocyanine green (ICG) (2.5–5 mg/kg) 24 hours prior to pancreatic resection. NIR imaging was performed during staging laparoscopy and after pancreas mobilization in situ and following resection ex vivo. Tumor fluorescence was quantified using tumor-to-background ratio (TBR). Fluorescence at the specimen margin was compared to pathology evaluation. Results: Procedures included 9 pancreaticoduodenectomies, 10 distal pancreatectomies, and 1 total pancreatectomy; 21 total specimens were obtained. Three out of 8 noninvasive tumors were fluorescent (mean TBR 2.59 ± 2.57). Twelve out of 13 invasive malignancies (n = 12 pancreatic adenocarcinoma, n = 1 cholangiocarcinoma) were fluorescent (mean TBR 4.42 ± 2.91). Fluorescence at the transection margin correlated with final pathologic assessment in 12 of 13 patients. Following neoadjuvant therapy, 4 of 5 tumors were fluorescent; these 4 tumors showed no treatment response on pathology assessment. One tumor had a significant treatment response and showed no fluorescence. Conclusions: Second window ICG reliably accumulates in invasive pancreatic malignancies and provides real-time feedback during pancreatectomy. NIR imaging may help to assess the response to neoadjuvant therapy.

William B. Coley developed bacterial therapy of cancer more than 100 years ago and had clinical success. James Ewing, a very famous cancer pathologist for whom the Ewing sarcoma is named, was Coley's boss at Memorial Hospital in New York and terminated Coley's bacterial therapy of cancer. A tumor from a patient with soft-tissue Ewing's sarcoma, who failed doxorubicin (DOX) therapy, was previously implanted in nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. In the present study, the Ewing's sarcoma PDOX was treated with tumor-targeting S. typhimurium A1-R expressing green fluorescent (GFP), alone and in combination with DOX. S. typhimurium A1-R-GFP was detected in the tumors after intratumor (i.t.) or intravenous (i.v.) injection. The combination of S. typhimurium A1-R and DOX significantly reduced tumor weight (37.8 ± 15.6 mg) compared to the untreated control (73.8 ± 10.1 mg, P < 0.01). S. typhimurium A1-R monotherapy-treated tumors tended to be smaller (50.9 ± 17.8 mg, P = 0.051). DOX monotherapy did not show efficacy (66.3 ± 26.4 mg, P = 0.82), as was the case with the patient. The PDOX model faithfully replicated the DOX resistance the Ewing's sarcoma had in the patient. S. typhimurium A1-R converted the Ewing's sarcoma from DOX resistant to sensitive. One can only wonder how bacterial therapy and immunotherapy of cancer would have developed over the past 80 years if Ewing did not stop Coley.

The Twist1 transcription factor promotes tumor invasion and metastasis by inducing epithelial-mesenchymal transition (EMT) and invadopodiamediated extracellular matrix (ECM) degradation. The critical transcription targets of Twist1 for mediating these events remain to be uncovered. Here, we report that Twist1 strongly induces expression of a disintegrin and metalloproteinase 12 (ADAM12). We observed that the expression levels of Twist1 mRNA and ADAM12 mRNA are tightly correlated in human breast tumors. Knocking down ADAM12 blocked cell invasion in a 3D mammary organoid culture. Suppression of ADAM12 also inhibited Twist1-induced tumor invasion and metastasis in human breast tumor xenografts, without affecting primary tumor formation. Mechanistically, knockdown of ADAM12 in breast cancer cells significantly reduced invadopodia formation and matrix degradation, and simultaneously increased overall cell adhesion to the ECM. Live-imaging analysis showed that knockdown of ADAM12 significantly inhibited focal adhesion turnover. Mechanistically, both the disintegrin and metalloproteinase domains of ADAM12 are required for its function at invadopodia, whereas the metalloproteinase domain is dispensable for its function at focal adhesions. Taken together, these data suggest that ADAM12 plays a crucial role in tumor invasion and metastasis by regulating both invadopodia and focal adhesions.

hM5A-IR800 demonstrated excellent tumor localization and a very bright signal. It is a promising agent for future clinical fluorescence-guided surgery applications.

Background and Objectives Delineation of adequate tumor margins is critical in oncologic surgery, particularly in resection of metastatic lesions. Surgeons are limited in visualization with bright-light surgery, but fluorescence-guided surgery (FGS) has been efficacious in helping the surgeon achieve negative margins. Methods The present study uses FGS in a mouse model that has undergone surgical orthotopic implantation (SOI) of colorectal liver metastasis tagged with green fluorescent protein (GFP). An anti-CEA antibody conjugated to DyLight 650 was used to highlight the tumor. Results The fluorescent antibody clearly demarcated the lesion at deeper tissue depth compared to GFP. Fluorescence of the anti-CEA-DyLight650 showed maximal tumor-to-liver contrast at 72 hr. Fifteen mice underwent bright-light surgery (BLS) versus FGS with GFP versus FGS with anti-CEA-DyLight650. Mice that underwent FGS had a significantly smaller area of residual tumor (P < 0.001) and significantly longer overall survival (P < 0.001) and disease-free survival (P < 0.001). Within the two FGS groups, mice undergoing surgery with anti-CEA-DyLight650 improved survival compared to only GFP labeling. Conclusions In the present report, we demonstrate that an anti-CEA antibody conjugated to a DyLight 650 nm dye clearly labeled colon cancer liver metastases, thereby enabling successful FGS.