Preclinical evaluation of L-fucoside from lapachol-loaded nanoemulsion as a strategy to breast cancer treatment.

Breast cancer prevails as the most common cancer in women, underscoring an urgent need for more effective therapies. This study explores the potential of our newly developed nanoemulsion containing a novel fucoside derivative of lapachol (NE-F-LapA) as an intravenous treatment strategy. We sought to overcome the solubility issues associated with fucoside with this improved drug delivery strategy that enhances tumor delivery and mitigates other dose-limiting toxicities. Nanoemulsion was prepared and characterized by DLS, zeta potential, encapsulation efficiency, and storage stability. Cytotoxicity against breast cancer cell lines (4T1 and MDA-MB-231) and non-tumor human fibroblasts (NTHF) were evaluated. In vivo assays included antitumoral activity performance and acute systemic toxicity in mice models. NE-F-LapA was synthesized and optimized to 200 nm size, - 20 mV zeta potential, and near-complete (>98%) drug encapsulation. Stability exceeded 6 months, and biological fluid exposure maintained suitable properties for administration. In vitro, NE-F-LapA showed high toxicity (3 µM) against 4T1 and MDA-MB-231, enhanced five times the breast cancer cell uptake and three times the selectivity when compared to normal cells. Systemic toxicity assessment in mice revealed no concerning hematological or biochemical changes. Finally, in a 4T1 breast tumor model, NE-F-LapA significantly inhibited growth by 50% of the subcutaneous 4T1 tumor and reduced lung metastases 5-fold versus control. Overall, tailored nanoemulsification of the lapachol derivative enabled effective intravenous administration and improved efficacy over the free drug, indicating promise for enhanced breast cancer therapy pending further optimization.

Addition of Peptide Receptor Radiotherapy to Immune Checkpoint Inhibition Therapy Improves Outcomes in Neuroendocrine Tumors.

Neuroendocrine tumors (NETs) are often diagnosed in advanced stages. Despite the advances in treatment approaches, including somatostatin analogs and peptide receptor radionuclide therapy (PRRT), these patients have no curative treatment option. Moreover, immunotherapy often yields modest results in NETs. We investigated whether combining PRRT using [177Lu]DOTATATE and immune checkpoint inhibition therapy improves treatment response in NETs. Methods: A gastroenteropancreatic NET model was generated by subcutaneous implantation of human QGP-1 cells in immune-reconstituted NOD.Cg-Prkdcscid Il2rgtm1Wjl /SzJ mice engrafted with human peripheral blood mononuclear cells (n = 96). Mice were randomly assigned to receive pembrolizumab (anti-PD1), [177Lu]DOTATATE (PRRT), simultaneous anti-PD1 and PRRT (S-PRRT), anti-PD1 on day 0 followed by PRRT on day 3 (delayed PRRT [D-PRRT]), PRRT on day 0 followed by anti-PD1 (early PRRT [E-PRRT]), or vehicle as control (n = 12/group). Human granzyme-B-specific [68Ga]NOTA-hGZP PET/MRI was performed before and 6 d after treatment initiation, as an indicator of T-cell activation. Response to treatment was based on tumor growth over 21 d and on histologic analyses of extracted tissues on flow cytometry for T cells, hematoxylin and eosin staining, and immunohistochemical staining. Results: [68Ga]NOTA-hGZP PET/MRI showed significantly increased uptake in tumors treated with E-PRRT, S-PRRT, and anti-PD1 on day 6 compared with baseline (SUVmax: 3.36 ± 0.42 vs. 0.73 ± 0.23; 2.36 ± 0.45 vs. 0.76 ± 0.30; 2.20 ± 0.20 vs. 0.72 ± 0.28, respectively; P < 0.001), whereas no significant change was seen in PET parameters in the D-PRRT, PRRT, or vehicle groups (P > 0.05). Ex vivo analyses confirmed the PET results showing the highest granzyme-B levels and T cells (specifically CD8-positive effector T cells) in the E-PRRT group, followed by the S-PRRT and anti-PD1 groups. Tumor growth follow-up showed the most significant tumor size reduction in the E-PRRT group (baseline to day 21, 205.00 ± 30.70 mm3 vs. 78.00 ± 11.75 mm3; P = 0.0074). Tumors showed less growth reduction in the PRRT, D-PRRT, and S-PRRT groups than in the E-PRRT group (P < 0.0001). The vehicle- and anti-PD-1-treated tumors showed continued growth. Conclusion: Combination of PRRT and anti-PD1 shows the most robust inflammatory response to NETs and a better overall outcome than immune checkpoint inhibition or PRRT alone. The most effective regimen is PRRT preceding anti-PD1 administration by several days.

HER3 PET Imaging Predicts Response to Pan Receptor Tyrosine Kinase Inhibition Therapy in Gastric Cancer.

PURPOSE: New generation of receptor tyrosine kinase inhibitors (RTKIs) have shown to improve survival in many solid tumors. However, an imaging biomarker is needed for patient selection and prediction of treatment response. This study evaluates the use of quantitative changes of HER3 on 68 Ga-NOTA-HER3P1 PET/MRI for prediction of early response to pan-RTKIs in gastric cancer (GCa). PROCEDURES: GCa cell lines were evaluated for expression of RTKs, and downstream signaling pathways (AKT and MAPK). Cell viability was assessed following 24-72 h of treatment with 0.01-1 µmol/L of afatinib, a pan-RTKI. HER3-expressing afatinib-sensitive (NCI-N87) and resistant cells (SNU16) were selected for evaluation of changes in RTKs expression and downstream pathways, with 24-72 h of 0.1 µmol/L afatinib treatment. 68 Ga-NOTA-HER3P1 PET/MRI was performed in subcutaneous NCI-N87 and SNU16 xenografts (nu:nu, n = 12/group) at baseline and 4 days after afatinib treatment (10 mg/kg, PO, daily). Temporal changes in PET measures were correlated to HER3 expression in tumors, tumor growth rate, and treatment response. RESULTS: With afatinib therapy, NCI-N87 cells showed increased total HER3 expression, and reduction of other RTKs and downstream nodes within 72 h, while SNU16 cells showed no significant change in total HER3 and downstream nodes. 68 Ga-HER3P1 PET/MRI showed increased uptake in NCI-N87 and no significant change in SNU16 tumors (day 4 vs. baseline SUVmean: 3.8 ± 0.7 vs. 1.6 ± 0.6, p < 0.05 in NCI-N87, and 1.5 ± 0.7 vs. 1.7 ± 0.7, p > 0.05 in SNU16). These findings were in concordance with HER3 expression in histopathological analyses and tumor growth over 3 weeks of treatment (mean tumor volume in treated vs. control: 11 ± 17 mm3 vs. 293 ± 79 mm3, p < 0.001 in NCI-N87, and 238 ± 91 mm3 vs. 282 ± 35 mm3, p > 0.05 in SNU16). CONCLUSIONS: Quantitative changes in HER3 PET could be used to predict response to pan-RTKI within few days after initiation of treatment and can help with personalizing GCa management.

Immune Checkpoint Inhibitor-Mediated Cancer Theranostics with Radiolabeled Anti-Granzyme B Peptide.

Although immune checkpoint inhibitors (ICI) have revolutionized cancer management, patient response can be heterogeneous, and the development of ICI resistance is increasingly reported. Novel treatment strategies are necessary not only to expand the use of ICI to previously unresponsive tumor types but also to overcome resistance. Targeted radionuclide therapy may synergize well with ICIs since it can promote a pro-inflammatory tumor microenvironment. We investigated the use of a granzyme B targeted peptide (GZP) as a cancer theranostic agent, radiolabeled with 68Ga (68Ga-GZP) as a PET imaging agent and radiolabeled with 90Y (90Y-GZP) as a targeted radionuclide therapy agent for combinational therapy with ICI in murine models of colon cancer. Our results demonstrate that GZP increasingly accumulates in tumor tissue after ICI and that the combination of ICI with 90Y-GZP promotes a dose-dependent response, achieving curative response in some settings and increased overall survival.

pH-responsive and folate-coated liposomes encapsulating irinotecan as an alternative to improve efficacy of colorectal cancer treatment.

Irinotecan (IRN) is a semisynthetic derivative of camptothecin that acts as a topoisomerase I inhibitor. IRN is used worldwide for the treatment of several types of cancer, including colorectal cancer, however its use can lead to serious adverse effects, as diarrhea and myelosuppression. Liposomes are widely used as drug delivery systems that can improve chemotherapeutic activity and decrease side effects. Liposomes can also be pH-sensitive to release its content preferentially in acidic environments, like tumors, and be surface-functionalized for targeting purposes. Herein, we developed a folate-coated pH-sensitive liposome as a drug delivery system for IRN to reach improved tumor therapy without potential adverse events. Liposomes were prepared containing IRN and characterized for particle size, polydispersity index, zeta potential, concentration, encapsulation, cellular uptake, and release profile. Antitumor activity was investigated in a murine model of colorectal cancer, and its toxicity was evaluated by hematological/biochemical tests and histological analysis of main organs. The results showed vesicles smaller than 200 nm with little dispersion, a surface charge close to neutral, and high encapsulation rate of over 90%. The system demonstrated prolonged and sustained release in pH-dependent manner with high intracellular drug delivery capacity. Importantly, the folate-coated pH-sensitive formulation had significantly better antitumor activity than the pH-dependent system only or the free drug. Tumor tissue of IRN-containing groups presented large areas of necrosis. Furthermore, no evidence of systemic toxicity was found for the groups investigated. Thus, our developed nanodrug IRN delivery system can potentially be an alternative to conventional colorectal cancer treatment.

The role of radionuclide probes for monitoring anti-tumor drugs efficacy: A brief review.

Despite recent advances in the development of new therapeutic agents and diagnostic imaging modalities, cancer is still one of the main causes of death worldwide. A better understanding of the molecular signature of cancer has promoted the development of a new generation of anti-cancer drugs and diagnostic agents that specifically target molecular components such as genes, ligands, receptors and signaling pathways. However, intrinsic heterogeneity of tumors has hampered the overall success of target therapies even among patients with similar tumor types but unpredictable different responses to therapy. In this sense, post-treatment response monitoring becomes indispensable and nuclear medicine imaging modalities could provide the tools for an early indication of therapeutic efficacy. Herein, we briefly discuss the current role of PET and SPECT imaging in monitoring cancer therapy together with an update on the current radiolabeled probes that are currently investigated for tumor therapy response assessment.

Development of imaging probes for bone cancer in animal models. A systematic review.

Bone is a dynamic tissue that is constantly remodeled throughout the lifetime to ensure the integrity of the skeleton. Primary cancer cells disseminate into circulation, often extravasating to bone, where they interact with the bone marrow to grow and proliferate, disrupting the bone homeostasis. Although primary bone tumors account for less than 0.2% of all cancers, bone is a common site for the development of metastases, as its microenvironment provides the necessary conditions for the growth and proliferation of cancer cells. Metastases to the skeletal system are observed in up to 70% of all cancer patients and the growth of disseminated tumor metastases is a major cause of mortality. As widely known, a non-invasive diagnosis of bone tumors at early stages is of great importance to provide insights that will help on the decision of therapy regimen, improving treatment outcomes. Early diagnosis of bone metastases is also an important step for establishing palliative care as they may cause serious endocrine, hematologic, neurologic and orthopedic complications as well as intolerable pain. Therefore, development of new imaging techniques, imaging moieties, and animal models to mimic these bone conditions, play an important role in improving the clinical outcome of this disease. In this review, we will briefly describe the advantages and disadvantages of the currently available imaging techniques that aim at identifying bone tumors. In addition, we will provide an update on the animal models applicable at mimicking bone tumor characteristics, as well as describe recent advances on the development of new imaging probes, in the preclinical settings including targeted nanoparticles and radiopharmaceuticals.