Inhibition of Tumor Growth against Chemoresistant Cholangiocarcinoma by a Proapoptotic Peptide Targeting Interleukin-4 Receptor

Interleukin-6 and Lymphocyte-to-Monocyte Ratio Indices Identify Patients with Intrahepatic Cholangiocarcinoma

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinoma (iCCA) is a fatal biliary tract cancer with a dismal prognosis due to ineffective diagnostic tools with limited clinical utility. This study investigated peripheral blood indices and cytokine levels to diagnose iCCA.

METHODS

Blood samples were collected from healthy subjects (n = 48) and patients with advanced-stage iCCA (n = 47) during a phase I and then phase II trial, respectively. Serum cytokines were measured using a flow cytometer. The peripheral blood indices were estimated based on laboratory data. Multi-linear regression analysis was applied, followed by a probability transformation. The cut-off value and model accuracy were determined using the receiver operating curve (ROC) and the area under the curve (AUC).

RESULTS

The interleukin-6 (IL6) and lymphocyte-to-monocyte ratio (LMR) were potential predictors of iCCA [AUC = 0.91 (0.85-0.97) and 0.81 (0.68-0.93); sensitivity = 0.70 and 0.91; specificity = 0.91 and 0.85, respectively]. Patients with IL6 concentrations higher than 11.635 pg/mL (OR = 23.33, p < 0.001) or LMR lower than 7.2 (OR = 58.08, p < 0.001) are at risk of iCCA development. Patients with IL6 levels higher than 21.83 pg/mL, between 15.95 and 21.83 pg/mL, between 8.8 and 15.94 pg/mL, and lower than 8.8 pg/mL were classified as very high-, high-, intermediate-, and low-risk, respectively. Patients with an LMR between 1 and 3.37, 3.38 and 5.76, 5.77 and 7.18, and higher than 7.18 were classified as very high-, high-, intermediate-, and low-risk, respectively.

CONCLUSIONS

LMR is recommended for iCCA screening since the estimation is based on a routine laboratory test, which is available in most hospitals.

A novel CD47-blocking peptide fused to pro-apoptotic KLA repeat inhibits lung cancer growth in mice

CD47 is highly expressed in many tumor tissues and induces immune evasion by interaction with SIRP-alpha (signal regulatory protein-alpha) expressed on tumor-associated macrophages. In this study, we identified a novel CD47-blocking peptide VK17 by phage display technique. A pro-apoptotic VK30 peptide was obtained after VK17 was fused to KLA amino acid repeat at C-termini. The VK30 was specifically bound to CD47 on lung cancer cells, and subsequently inducing lung cancer cell apoptosis. Meanwhile, the expression of Bax was increased, whereas the expression of Bcl-2 and Ki-67 were reduced in the VK30-treated lung cancer cells. In addition, VK30 effectively improved the phagocytic activity of macrophages against VK30-pretreated lung cancer cells. Combinational treatment of lung cancer cells with blocking antibody anti-CD47 and VK30 additively enhanced VK30 binding to CD47, subsequently increasing lung cancer cell apoptosis and macrophage phagocytosis. Intraperitoneal administration of 2 mg/kg VK30 induced effective trafficking of VK30 into tumor tissues, and suppressing lung cancer cell growth in mice, associated with increased tumor cell apoptosis, macrophage activation and phagocytosis in vivo. The expression of CD47 was reduced in the VK30-treated tumor tissues and the expression level was positively correlated to tumor size. In addition, VK30 reduced the infiltration of CD11b+Ly6G+ neutrophils and CD11b+Ly6C+Ly6G+ granulocytic myeloid-derived suppressor cells (Gr-MDSCs) in tumor tissues, associated with suppressed expression of tumorigenic IL-6 and TNF-alpha from these cell types. Thereby, VK30 exerted anti-tumor effects in mice through inducing tumor cell apoptosis and macrophage phagocytosis. VK30 would be a novel therapeutic peptide in lung cancer immunotherapy.

Peptides as multifunctional players in cancer therapy

Peptides exhibit lower affinity and a shorter half-life in the body than antibodies. Conversely, peptides demonstrate higher efficiency in tissue penetration and cell internalization than antibodies. Regardless of the pros and cons of peptides, they have been used as tumor-homing ligands for delivering carriers (such as nanoparticles, extracellular vesicles, and cells) and cargoes (such as cytotoxic peptides and radioisotopes) to tumors. Additionally, tumor-homing peptides have been conjugated with cargoes such as small-molecule or chemotherapeutic drugs via linkers to synthesize peptide-drug conjugates. In addition, peptides selectively bind to cell surface receptors and proteins, such as immune checkpoints, receptor kinases, and hormone receptors, subsequently blocking their biological activity or serving as hormone analogs. Furthermore, peptides internalized into cells bind to intracellular proteins and interfere with protein-protein interactions. Thus, peptides demonstrate great application potential as multifunctional players in cancer therapy.

Constructing New Acid-Activated Anticancer Peptide by Attaching a Desirable Anionic Binding Partner Peptide

Improving the cell selectivity of anticancer peptides (ACPs) is a major hurdle in their clinical utilization. In this study, a new acid-activated ACP was designed by conjugating a cationic ACP LK to its anionic binding partner peptide (LEH) via a disulfide linker to trigger antitumor activity at acidic pH while masking its killing activity at normal pH. Three anionic binding peptides containing different numbers of glutamic acid (Glu) and histidine were engineered to obtain an efficient acid-activated ACP. The conjugates LK-LEH2 and LK-LEH3 exhibited 6.1 and 8.0-fold higher killing activity at pH 6.0 relative to at pH 7.4, respectively, suggesting their excellent pH-dependent antitumor activity; and their cytotoxicity was 10-fold lower than that of LK. However, LK-LEH4 had no pH-responsive killing effect. Interestingly, increasing the number of Glu from 2 to 4 increased the pH-response of the physical mixture of LK and LEH; conversely, they weakly decreased the cytotoxicity of LK, suggesting that the conjugate connection was required to achieve excellent pH dependence while maintaining minimum toxicity. LK-LEH2 and LK-LEH3 were more enzymatically stable than LK, indicating their potential for in vivo application. Our work provided a basis for designing promising ACPs with good selectivity and low toxicity.