Intraoperative Molecular Fluorescence Imaging of Pancreatic Cancer by Targeting Vascular Endothelial Growth Factor: A Multicenter Feasibility Dose-Escalation Study

Tumour Marker Expression in Head and Neck Malignancies to Identify Potential Targets for Intraoperative Molecular Near-Infrared Imaging

BACKGROUND

Oral and laryngeal squamous cell carcinoma (OSCC and LSCC) and papillary thyroid carcinoma (PTC) are common head and neck cancers (HNCs) typically treated surgically. Challenges in tumour delineation often lead to inadequate resection margins in OSCC and LSCC, and missed multifocality in PTC. Fluorescence imaging (FLI) using near-infrared tumour-targeting tracers may improve intraoperative identification of malignancy, facilitating precise excision. This study evaluates six potential FLI targets in OSCC, LSCC and PTC.

MATERIALS AND METHODS

Immunohistochemical staining was performed on OSCC (n = 20), LSCC (n = 10) and PTC (n = 10), assessing CEA, c-Met, EpCAM, EGFR, integrin αvβ6 and VEGF-α. Expression was scored (0-12) using the total immunostaining score (TIS) system, and categorized into absent (TIS 0), low (TIS 1-5), moderate (TIS 6-8) or high (TIS 9-12).

RESULTS

Integrin αvβ6 showed significant overexpression in OSCC (TIS: 12; p < 0.001) and LSCC (TIS: 8; p = 0.002), with 80% of OSCC and 90% of LSCC exhibiting moderate-high expression. Similarly, EGFR expression was moderate-high in most OSCC (87.5%; TIS: 8) and universally high in LSCC (100%; TIS: 12). In PTC, EGFR and VEGF-α expressions were low-moderate, but significantly higher than in healthy tissue (TIS: 6; p < 0.006).

CONCLUSION

This study highlights integrin αvβ6 and EGFR as viable FLI targets in OSCC and LSCC, especially integrin αvβ6 for tumour margin delineation. In PTC, despite lower expressions, the significant overexpression of VEGF-α, c-MET, and EGFR suggests their potential as FLI targets. Our findings support the development of tumour-targeted FLI tracers to improve surgical precision in HNC.

Miniaturized Fab' imaging probe derived from a clinical antibody: Characterization and imaging in CRISPRi-attenuated mammary tumor models

Clinical imaging-assisted oncosurgical navigation requires cancer-specific miniaturized optical imaging probes. We report a near-infrared (NIR) Fab'-based epidermal growth factor receptor (EGFR)-specific probe carrying 3 NIR fluorophores (Fab'-800CW), which retained high-affinity binding to EGFR ectodomain (equilibrium KD E = 1 nM). Fab'-800CW showed a robust 4-times gain of fluorescence intensity (FI) and a 20% lifetime (FLT) increase under the conditions mimicking intracellular degradation. The probe was tested by using triple-negative breast cancer (TNBC) cell lines obtained by applying CRISPR interference (CRISPRi) effect of EGFR-targeting sgRNA and dCas9-KRAB chimera coexpression in MDA-MB-231 cells (WT cells). FI imaging in cell culture proved a 50% EGFR expression attenuation by CRISPRi. FI imaging in animals harboring attenuated or WT TNBC tumors with ex vivo corroboration identified differences between WT and CRISPRi tumors FI at 30 min post injection. Our results suggest the feasibility of EGFR expression imaging using a Fab'-based probe relevant for imaging-guided cancer surgery.

DOTA-Based Plectin-1 Targeted Contrast Agent Enables Detection of Pancreatic Cancer in Human Tissue

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and lethal malignancy with extremely poor patient survival rates. A key reason for the poor prognosis is the lack of effective diagnostic tools to detect the disease at curable, premetastatic stages. Tumor surgical resection is PDAC's first-line treatment, however distinguishing between cancerous and healthy tissue with current imaging tools remains a challenge. In this work, we report a DOTA-based fluorescent probe targeting plectin-1 for imaging PDAC with high specificity. To enable heterogeneous functionalization of the DOTA-core with multiple targeting peptide units and the fluorophore, a novel, fully clickable synthetic route that proceeds in one pot was developed. Extensive validation of the probe set the stage for PDAC detection in mice and human tissue. Altogether, these findings may pave the way for improved clinical understanding and early detection of PDAC progression as well as more accurate resection criteria.

A carbonic anhydrase-targeted NIR-II fluorescent cisplatin theranostic nanoparticle for combined therapy of pancreatic tumors

Optically active organic nanoparticles capable of emitting strong near-infrared II (NIR-II) fluorescence and eliciting tumor hyperthermia are promising for tumor imaging and photothermal therapy (PTT). However, their applications for the treatment of pancreatic tumors via mere PTT are challenging as both the nanoparticles and light are hard to enter the deeply located pancreatic tumors. Here, we report a NIR-II light excitable, carbonic anhydrase (CA)-targeting cisplatin prodrug-decorated nanoparticle (IRNPs-SBA/PtIV) for NIR-II fluorescence imaging (FLI)-guided combination PTT and chemotherapy of pancreatic tumors. IRNPs-SBA/PtIV is designed to hold a high photothermal conversion efficiency (PCE ≈ 65.17 %) under 1064 nm laser excitation, a strong affinity toward CA (Kd = 14.40 ± 5.49 nM), and a prominent cisplatin release profile in response to glutathione (GSH) and 1064 nm laser irradiation. We show that IRNPs-SBA/PtIV can be actively delivered into pancreatic tumors where the CA is upregulated, and emits NIR-II fluorescence to visualize tumors with a high sensitivity and penetration depth under 980 nm laser excitation. Moreover, the tumor-resided IRNPs-SBA/PtIV can efficiently inhibit the CA activity and consequently, relieve the acidic and hypoxic tumor microenvironment, benefiting to intensify chemotherapy. Guided by the NIR-II FLI, IRNPs-SBA/PtIV is capable of efficiently inhibiting pancreatic tumor growth via combinational PTT and chemotherapy with 1064 nm laser excitation under a low-power density (0.5 W cm-2, 10 min). This study demonstrates promise to fabricate NIR-II excitable nanoparticles for FLI-guided precise theranostics of pancreatic tumors.

Identification of Optimal Tissue-Marking Dye Color for Pathological Evaluation in Fluorescence Imaging Using IRDye800CW

PURPOSE

Fluorescence-guided surgery using a tumor-specific antibody-dye conjugate is useful in various cancer types. Fluorescence imaging is a valuable tool both intraoperatively and postoperatively for ex vivo imaging. The color of inks used for tumor specimens during ex vivo specimen processing in pathology is an important consideration for fluorescence imaging since the absorption/emission of the dyes may interfere with the fluorescent dye. This study assesses suitable ink colors for use specifically with IRDye800CW fluorescence imaging.

PROCEDURES

Eight tissue-marking inks or dyes (TMDs) commonly used for pathological evaluation were assessed. Agarose tissue-mimicking phantoms containing Panitumumab-IRDye800CW were used as an initial model. Mean fluorescence intensity was measured at 800 nm using both Pearl Trilogy as a closed-field fluorescence imaging system and pde-neo II as an open-field fluorescence imaging system before and after TMD application. An in vivo mouse xenograft model using the human head and neck squamous cell carcinoma FaDu cell line was then used in conjunction with TMDs.

RESULTS

The retained IRDye800CW fluorescence on Pearl Trilogy was as follows: yellow at 91.0 ± 4.5%, red at 90.6 ± 2.7%, orange at 88.2 ± 2.2%, violet at 56.6 ± 1.1%, lime at 40.9 ± 1.8%, green at 19.3 ± 2.8%, black at 13.3 ± 0.6%, and blue at 8.1 ± 0.2%. The retained IRDye800CW fluorescence on pde-neo II was as follows: yellow at 86.5 ± 6.4%, red at 77.0 ± 6.2%, orange at 76.9 ± 2.8%, lime at 72.5 ± 9.5%, violet at 59.7 ± 0.4%, green at 30.1 ± 6.9%, black at 17.0 ± 2.7%, and blue at 6.7 ± 1.7%. The retained IRDye800CW fluorescence in yellow and blue TMDs was 42.1 ± 14.9% and 0.2 ± 0.2%, respectively in the mouse experiment (p = 0.039).

CONCLUSION

Yellow, red, and orange TMDs should be used, and blue and black TMDs should be avoided for evaluating tumor specimens through fluorescence imaging using IRDye800CW.

Intraoperative Imaging in Hepatopancreatobiliary Surgery

Hepatopancreatobiliary surgery belongs to one of the most complex fields of general surgery. An intricate and vital anatomy is accompanied by difficult distinctions of tumors from fibrosis and inflammation; the identification of precise tumor margins; or small, even disappearing, lesions on currently available imaging. The routine implementation of ultrasound use shifted the possibilities in the operating room, yet more precision is necessary to achieve negative resection margins. Modalities utilizing fluorescent-compatible dyes have proven their role in hepatopancreatobiliary surgery, although this is not yet a routine practice, as there are many limitations. Modalities, such as photoacoustic imaging or 3D holograms, are emerging but are mostly limited to preclinical settings. There is a need to identify and develop an ideal contrast agent capable of differentiating between malignant and benign tissue and to report on the prognostic benefits of implemented intraoperative imaging in order to navigate clinical translation. This review focuses on existing and developing imaging modalities for intraoperative use, tailored to the needs of hepatopancreatobiliary cancers. We will also cover the application of these imaging techniques to theranostics to achieve combined diagnostic and therapeutic potential.

Mucins as contrast agent targets for fluorescence-guided surgery of pancreatic cancer

Pancreatic cancer is difficult to resect due to its unique challenges, often leading to incomplete tumor resections. Fluorescence-guided surgery (FGS), also known as intraoperative molecular imaging and optical surgical navigation, is an intraoperative tool that can aid surgeons in complete tumor resection through an increased ability to detect the tumor. To target the tumor, FGS contrast agents rely on biomarkers aberrantly expressed in malignant tissue compared to normal tissue. These biomarkers allow clinicians to identify the tumor and its stage before surgical resection and provide a contrast agent target for intraoperative imaging. Mucins, a family of glycoproteins, are upregulated in malignant tissue compared to normal tissue. Therefore, these proteins may serve as biomarkers for surgical resection. Intraoperative imaging of mucin expression in pancreatic cancer can potentially increase the number of complete resections. While some mucins have been studied for FGS, the potential ability to function as a biomarker target extends to the entire mucin family. Therefore, mucins are attractive proteins to investigate more broadly as FGS biomarkers. This review summarizes the biomarker traits of mucins and their potential use in FGS for pancreatic cancer.

Detection of Tumour-Targeted IRDye800CW Tracer with Commercially Available Laparoscopic Surgical Systems

(1) Introduction: Near-infrared fluorescence (NIRF) combined with tumour-targeted tracers, such as bevacizumab-800CW, could aid surgical decision-making. This study explored the use of IRDye800CW, conjugated to bevacizumab, with four commercially available NIRF laparoscopes optimised for indocyanine green (ICG). (2) Methods: A (lymph node) phantom was made from a calibration device for NIRF and tissue-mimicking material. Serial dilutions of bevacizumab-800CW were made and ICG functioned as a reference. System settings, working distance, and thickness of tissue-mimicking material were varied to assess visibility of the fluorescence signal and tissue penetration. Tests were performed with four laparoscopes: VISERA ELITE II, Olympus; IMAGE1 S™ 4U Rubina, KARL STORZ; ENDOCAM Logic 4K platform, Richard Wolf; da Vinci Xi, Intuitive Surgical. (3) Results: The lowest visible bevacizumab-800CW concentration ranged between 13-850 nM (8-512 times diluted stock solution) for all laparoscopes, but the tracer was not visible through 0.8 cm of tissue in all systems. In contrast, ICG was still visible at a concentration of 0.4 nM (16,384 times diluted) and through 1.6-2.4 cm of tissue. Visibility and tissue penetration generally improved with a reduced working distance and manually adjusted system settings. (4) Conclusion: Depending on the application, bevacizumab-800CW might be sufficiently visible with current laparoscopes, but optimisation would widen applicability of tumour-targeted IRDye800CW tracers.

Future in precise surgery: Fluorescence-guided surgery using EVs derived fluorescence contrast agent

Surgery is the only cure for many solid tumors, but positive resection margins, damage to vital nerves, vessels and organs during surgery, and the range and extent of lymph node dissection are significant concerns which hinder the development of surgery. The emergence of fluorescence-guided surgery (FGS) means a farewell to the era when surgeons relied only on visual and tactile feedback, and it gives surgeons another eye to distinguish tumors from normal tissues for precise resection and helps to find a balance between complete tumor lesions removal and maximal organ function conservation. However, the existing synthetic fluorescence contrast agent has flaws in safety, specificity and biocompatibility to various extents. Extracellular vesicles (EVs) are a group of heterogeneous types of cell-derived membranous structures present in all biological fluids. EVs, especially engineered targeting EVs, play an increasingly important role in drug delivery because of their good biocompatibility, validated safety and targeting ability. Nevertheless, few studies have employed EVs loaded with fluorophores to construct fluorescence contrast agents and used them in FGS. Here, we systematically reviewed the current state of knowledge regarding FGS, fundamental characteristics of EVs, and the development of engineered targeting EVs, and put forward a novel strategy and procedures to produce EVs-based fluorescence contrast agent used in fluorescence-guided surgery.