Jonathan C. DeLong

Tumor-targeting Salmonella typhimurium A1-R in combination with doxorubicin eradicate soft tissue sarcoma in a patient-derived orthotopic xenograft (PDOX) model

A patient with high grade undifferentiated pleomorphic soft-tissue sarcoma from a striated muscle was grown orthotopically in the right biceps femoris muscle of mice to establish a patient-derived orthotopic xenograft (PDOX) model. Twenty PDOX mice were divided into 4 groups: G1, control without treatment; G2, Salmonella typhimurium (S. typhimurium)A1-R administered by intratumoral (i.t.) injection once a week for 4 weeks; G3, doxorubicin (DOX) administered by intraperitoneal (i.p.) injection once a week for 4 weeks; G4, S. typhimurium A1-R (i.t.) administered once a week for 2 weeks followed by i.p. doxorubicin once a week for 2 weeks. On day 25 from the initiation of treatment, tumor volume in G2, G3, and G4 was significantly lower than G1. Mice found without gross tumor included one mouse (20%) in G2; one mouse (20%) in G3; and 3 mice (60%) in G4. Body weight loss did not significantly differ between the 3 treated groups or from the untreated control. Histological examination revealed eradication of tumor only in G4 where mice were treated with S. typhimurium A1-R followed by DOX. Our present study indicates future clinical potential of combining S. typhimurium A1-R with chemotherapy such as DOX for soft tissue sarcoma patients.

Effective molecular targeting of CDK4/6 and IGF-1R in a rare FUS-ERG fusion CDKN2A -deletion doxorubicin-resistant Ewing's sarcoma patient-derived orthotopic xenograft (PDOX) nude-mouse model

Ewings sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewings sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewings sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm3: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewings sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer.

The irony of highly-effective bacterial therapy of a patient-derived orthotopic xenograft (PDOX) model of Ewing's sarcoma, which was blocked by Ewing himself 80 years ago

ABSTRACT 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 Coleys boss at Memorial Hospital in New York and terminated Coleys bacterial therapy of cancer. A tumor from a patient with soft-tissue Ewings 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 Ewings 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 Ewings sarcoma had in the patient. S. typhimurium A1-R converted the Ewings 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.

MEK inhibitors cobimetinib and trametinib, regressed a gemcitabine-resistant pancreatic-cancer patient-derived orthotopic xenograft (PDOX)

A pancreatic ductal adenocarcinoma (PDAC), obtained from a patient, was grown orthotopically in the pancreatic tail of nude mice to establish a patient-derived orthotopic (PDOX) model. Seven weeks after implantation, PDOX nude mice were divided into the following groups: untreated control (n = 7); gemcitabine (100 mg/kg, i.p., once a week for 2 weeks, n = 7); cobimetinib (5 mg/kg, p.o., 14 consecutive days, n = 7); trametinib (0.3 mg/kg, p.o., 14 consecutive days, n = 7); trabectedin (0.15 mg/kg, i.v., once a week for 2 weeks, n = 7); temozolomide (25 mg/kg, p.o., 14 consecutive days, n = 7); carfilzomib (2 mg/kg, i.v., twice a week for 2 weeks, n = 7); bortezomib (1 mg/kg, i.v., twice a week for 2 weeks, n = 7); MK-1775 (20 mg/kg, p.o., 14 consecutive days, n = 7); BEZ-235 (45 mg/kg, p.o., 14 consecutive days, n = 7); vorinostat (50 mg/kg, i.p., 14 consecutive days, n = 7). Only the MEK inhibitors, cobimetinib and trametinib, regressed tumor growth, and they were more significantly effective than other therapies (p < 0.0001, respectively), thereby demonstrating the precision of the PDOX models of PDAC and its potential for individualizing pancreatic-cancer therapy.

Current status and future perspectives of fluorescence-guided surgery for cancer

Curative cancer surgery is dependent on the removal of all primary tumor and metastatic cancer cells. Preoperative imaging, intraoperative inspection and palpation, as well as pathological margin confirmation aid the surgeon, but these methods are lacking in sensitivity and can be highly subjective. Techniques in fluorescence-guided surgery (FGS) are emerging that selectively illuminate cancer cells, enhancing the distinction between tumors and surrounding tissues with the potential for single-cell sensitivity. FGS enhances tumor detection, surgical navigation, margin confirmation, and in some cases can be combined with therapeutic techniques to eliminate microscopic disease. In this review, we describe the preclinical developments and currently-used techniques for FGS.

Indocyanine green (ICG) fluorescence-guided laparoscopic adrenalectomy

Laparoscopic adrenalectomy has become the standard of care for many adrenal tumors. However, the success of the operation hinges on identifying the adrenal vein and complete tumor resection. We demonstrate the use of a commercially available near infrared fluorescent imaging system to clearly delineate the vascular anatomy of adrenal neoplasms and enhance the border between tumor and normal tissue. We hypothesize that this will increase the safety of laparoscopic adrenalectomy.

Color-coded intravital imaging demonstrates a transforming growth factor-β (TGF-β) antagonist selectively targets stromal cells in a human pancreatic-cancer orthotopic mouse model

ABSTRACT Pancreatic cancer is a recalcitrant malignancy, partly due to desmoplastic stroma which stimulates tumor growth, invasion, and metastasis, and inhibits chemotherapeutic drug delivery. Transforming growth factor-β (TGF-β) has an important role in the formation of stromal desmoplasia. The present study describes the ability of color-coded intravital imaging to demonstrate the efficacy of a TGF-β inhibitor to target stroma in an orthotopic mouse model of pancreatic cancer. The BxPC-3 human pancreatic adenocarcinoma cell line expressing green fluorescent protein (GFP), which also has a high TGF-β expression level, was used in an orthotopic model in transgenic nude mice ubiquitously expressing red fluorescent protein (RFP). Fourteen mice were randomized into a control group (n = 7, vehicle, i.p., weekly, for 3 weeks) and a treated group (n = 7, SB431542 [TGF-β receptor type I inhibitor] 0.3 mg, i.p., weekly, for 3 weeks). Stromal cells expressing RFP and cancer cells expressing GFP were observed weekly for 3 weeks by real-time color-coded intravital imaging. The RFP fluorescence area from the stromal cells, relative to the GFP fluorescence area of the cancer cells, was significantly decreased in the TGF-β-inhibitor-treatment group compared to the control group. The present study demonstrated color-coded imaging in an orthotopic pancreatic-cancer cell-line mouse model can readily detect the selective anti-stromal-cell targeting of a TGF-β inhibitor.

MEK inhibitor trametinib in combination with gemcitabine regresses a patient-derived orthotopic xenograft (PDOX) pancreatic cancer nude mouse model

Pancreatic cancer is resistant to treatment and needs precision individualized therapy to improve the outcome of this disease. Previously, we demonstrated that trametinib (TRA), a MEK inhibitor, could inhibit a pancreatic cancer patient-derived orthotopic xenograft (PDOX). In the present study, we show that gemcitabine (GEM) in combination with TRA was more effective than TRA alone. We implanted a patient pancreatic cancer orthotopically in the pancreatic tail of nude mice to establish the PDOX model. After seven weeks of tumor growth, we divided 32 pancreatic-cancer PDOX nude mice into 4 groups of eight: untreated control; GEM (once a week for 2 weeks); TRA (14 consecutive days); GEM + TRA (GEM: once a week for 2 weeks, TRA:14 consecutive days). We found that treated mice on day 14 had significantly reduced tumor volume in comparison to untreated control. TRA and the combination of GEM + TRA therapy significantly inhibited tumor development in comparison to GEM alone. However, GEM + TRA inhibited the PDOX tumor growth significantly greater than TRA alone. These results suggest the clinical potential of the combination of TRA and GEM for pancreatic cancer.

The benefits and limitations of robotic assisted transhiatal esophagectomy for esophageal cancer

Robotic-assisted transhiatal esophagectomy (RATE) is a minimally invasive approach to total esophagectomy with less morbidity but equivalent efficacy when compared with the traditional open approach. The robotic platform offers numerous technical advantages that assist with the esophageal dissection, which allows the procedure to be completed without entry into the thoracic cavity. The major criticism of the transhiatal approach is that it forfeits the ability of the surgeon to perform a formal lymphadenectomy, but this does not appear to affect long-term survival.

Identifying lost surgical needles with visible and near infrared fluorescent light emitting microscale coating

Background. Retained foreign bodies (RFOs) have substantial clinical and financial consequences. In laparoscopic surgery, RFOs can be a cause of needing to convert a minimally invasive surgery (MIS) procedure to an open operation. A coating for surgical models was developed to augment localization of needles using fluorescence appropriate for open and minimally invasive surgeries procedures. Methods. An epoxy matrix containing both dansyl chloride and indocyanine green was coated as visible and near infrared labels, respectively. With ultraviolet excitation, dansyl chloride emits green fluorescence and with NIR excitation, the ICG dye emits radiation observable with specialized near infrared capable laparoscopes. To evaluate the coatings, open and laproscopic surgeries were simulated in rabbits. Surgeons blinded to the type of needles (coated or non‐coated) were timed while finding needles in standard conditions and with the use of the adjunct coatings. Control needles not located within 300 seconds were researched with the corresponding near infrared or ultraviolet light. Localization time was evaluated for statistical significance, P < .05. Results. All dual dye coated needles searched utilizing the near infrared camera (n = 26) or ultraviolet light (n = 26) were located within 300 seconds. Conversely, 9 needles in both control settings (no dye usage) were not located within 300 seconds. Mean time to locate control needles in open surgery and laparoscopic surgery was statistically 2–3× greater than time to localization with the use of dye as an adjunct (P = .0027 open, P < .001 laparoscopic). Conclusion. Incorporation of a dual‐dye fluorescent coating on surgical needles improved the efficiency of locating needles, may minimize the need to convert minimally invasive surgeries procedures to open, and may decrease the consequences of a missed RFO.