Enhancing precision in colorectal cancer surgery: development of an LGR5-targeting RSPO1 peptide mimetic as a contrast agent for intraoperative fluorescence molecular imaging.

Colorectal cancer (CRC) is the third most common cancer worldwide. In the United States alone, CRC was responsible for approximately 52,550 deaths in 2023, with an estimated 153,020 new cases. CRC presents with synchronous peritoneal spread in 5-10% of patients, and up to 20-50% of patients with recurrent disease will develop metachronous colorectal cancer peritoneal metastatic (CRC-PM) disease. Eradication of the tumor, tumor margins and microscopic residual disease is paramount, as microscopic residual disease is associated with local recurrences, with 5-year survival rates of less than 35%. The success of resection and reduction of residual disease depends on the accuracy with which cancer cells and normal tissue can be intra-operatively distinguished. Fluorescence Molecular Imaging (IFMI) and tumor-targeted contrast agents represent a promising approach for intraoperative detection and surgical intervention. Proper target selection, the development of scalable imaging agents and enhanced real-time tumor and tumor microenvironment imaging are critical to enabling enhanced surgical resection. LGR5 (leucine-rich repeat-containing G-protein-coupled receptor 5), a colonic crypt stem cell marker and the receptor for the R-spondins (RSPO) in the Wnt signaling pathway, is also expressed on colorectal cancer stem cells (CSC) and on CRC tumors and metastases, suggesting it could be a useful target for imaging of CRC. However, there are numerous diverging reports on the role of LGR5 in CRC therapy and outcomes. Herein, we report on the synthesis and validation of a 37 amino acid RSPO1-mimetic peptide, termed RC18, that was specifically designed to access the R-spondin binding site of LGR5 to potentially be used for interoperative imaging of CRC-PM. The receptor-binding capabilities of the RC18 indicate that direct interactions with LGR5 neither significantly increased LGR5 signaling nor blocked RSPO1 binding and signal transduction, suggesting that the RSPO1-mimetic is functionally inert, making it an attractive contrast agent for intraoperative CRC-PM imaging.

The Sustained Induction of c-MYC Drives Nab-Paclitaxel Resistance in Primary Pancreatic Ductal Carcinoma Cells.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited and, very often, ineffective medical and surgical therapeutic options. The treatment of patients with advanced unresectable PDAC is restricted to systemic chemotherapy, a therapeutic intervention to which most eventually develop resistance. Recently, nab-paclitaxel (n-PTX) has been added to the arsenal of first-line therapies, and the combination of gemcitabine and n-PTX has modestly prolonged median overall survival. However, patients almost invariably succumb to the disease, and little is known about the mechanisms underlying n-PTX resistance. Using the conditionally reprogrammed (CR) cell approach, we established and verified continuously growing cell cultures from treatment-naïve patients with PDAC. To study the mechanisms of primary drug resistance, nab-paclitaxel-resistant (n-PTX-R) cells were generated from primary cultures and drug resistance was verified in vivo, both in zebrafish and in athymic nude mouse xenograft models. Molecular analyses identified the sustained induction of c-MYC in the n-PTX-R cells. Depletion of c-MYC restored n-PTX sensitivity, as did treatment with either the MEK inhibitor, trametinib, or a small-molecule activator of protein phosphatase 2a. IMPLICATIONS: The strategies we have devised, including the patient-derived primary cells and the unique, drug-resistant isogenic cells, are rapid and easily applied in vitro and in vivo platforms to better understand the mechanisms of drug resistance and for defining effective therapeutic options on a patient by patient basis.

Use of naloxone nasal spray 4 mg in the community setting: a survey of use by community organizations.

OBJECTIVE: Naloxone hydrochloride, an opioid antagonist, has been approved as a concentrated 4 mg dose intranasal formulation for the emergency treatment of known or suspected opioid overdose. This new formulation is easier to use and contains a higher dose of naloxone compared with earlier, unapproved kits. A survey of first responders and community-based organizations was conducted to understand initial real-world experiences with this new formulation for opioid overdose reversal. METHODS: In August 2016, 152 US organizations known to have received units of the approved 4 mg dose/unit naloxone nasal spray (Narcan®1 nasal spray 4 mg; NNS) were surveyed regarding experiences using this formulation and availability of recorded data on these cases. Descriptive statistics were calculated based on the number of responses received for each item. RESULTS: Eight first-responder or community-based organizations provided case report data on 261 attempted overdose reversals using NNS, with survival reported for 245 cases. Successful overdose reversals were reported in 98.8% (242/245) of cases; most cases (73.5%; 125/170) reported a time to response of ≤5 minutes after NNS administration. Heroin was the substance reportedly involved in a majority (95.4%; 165/173) of these cases; fentanyl was reported to be involved in 5.2% (9/173) of the cases. Many reversals (97.6%; 248/254) involved administration of ≤2 units of NNS. Three deaths were reported (NNS was reported to have been administered too late for two cases [the individuals were deceased prior to NNS administration]; details were not provided for the third case). The most commonly reported observed events were "withdrawal" (14.3%; 28/196); "nausea", "vomiting", or "gagging/retching" (10.2%; 20/196); and "irritability" or "anger" (8.7%; 17/196). CONCLUSION: This survey of data provided by first-responder and community-based organizations indicated that NNS was successful at reversing the effects of opioid overdose in most reported cases.