TC-14, a cathelicidin-derived antimicrobial peptide with broad-spectrum antibacterial activity and high safety profile.

Cathelicidins, a major class of antimicrobial peptides (AMPs), hold considerable potential for antimicrobial drug development. In the present study, we identified a novel cathelicidin AMP (TC-33) derived from the Chinese tree shrew. Despite TC-33 demonstrating weak antimicrobial activity, the novel peptide TC-14, developed based on its active region, exhibited a 432-fold increase in antimicrobial activity over the parent peptide. Structural analysis revealed that TC-14 adopted an amphipathic α-helical conformation. The bactericidal mechanism of TC-14 involved targeting and disrupting the bacterial membrane, leading to rapid membrane permeabilization and rupture. Furthermore, TC-14 exhibited a high-safety profile, as evidenced by the absence of cytotoxic and hemolytic activities, as well as high biocompatibility and safety in vivo. Of note, its potent antimicrobial activity provided significant protection in a murine model of skin infection. Overall, this study presents TC-14 as a promising drug candidate for antimicrobial drug development.

Foritinib in advanced ROS1-rearranged non-small-cell lung cancer in China: a multicentre, open-label, single-arm, phase 2 study.

BACKGROUND: Currently approved targeted treatment for ROS1-rearranged non-small-cell lung cancer (NSCLC) has either inadequate intracranial activity or CNS-related toxicities. We evaluated the efficacy and safety of foritinib, a novel ALK and ROS1 inhibitor, in patients with advanced ROS1-rearranged NSCLC. METHODS: This two-part (phase 2a and 2b), multicentre, single-arm, open-label, phase 2 study was done in 29 centres in China. Eligible participants were adults (aged ≥18 years) with histologically or cytologically confirmed ROS1-rearranged, locally advanced or metastatic stage IIIB-IV NSCLC, with an Eastern Cooperative Oncology Group performance status of 2 or less. Patients who had previously received no or one ROS1 inhibitor were enrolled into phase 2a, and patients who were naive to ROS1 inhibitor therapy were enrolled into phase 2b cohort 1. Participants in phase 2a received 80, 120, 160, or 210 mg foritinib succinate (foritinib) orally once daily over 21-day cycles; patients in phase 2b received the recommended phase 2 dose of 160 mg. The primary endpoint was objective response rate, assessed by the independent review committee in the full analysis set (ie, all participants who received at least one dose of study treatment). The safety analysis set included all participants who received at least one dose of study treatment and had available safety assessments. This study is ongoing and is registered with ClinicalTrials.gov, NCT04237805. FINDINGS: Between March 26, 2020, and Dec 29, 2022, 104 patients were enrolled and treated. Six patients who had previously received more than one ROS1 inhibitor were enrolled in phase 2a before a protocol amendment stating that patients in this phase should have received no more than one ROS1 inhibitor; these patients were included in the safety analysis but excluded from the efficacy analysis of the ROS1-inhibitor-pretreated cohort. Therefore, the efficacy analysis set (n=98) included 42 patients from phase 2a (17 who were ROS1 inhibitor naive and 25 who had previously received ROS1 inhibitor) and 56 patients from phase 2b cohort 1. In phase 2a, the objective response rate was 94% (95% CI 71-100; 16 of 17 patients) in patients who were ROS1 inhibitor naive and 40% (21-61; ten of 25) in patients who had previously received ROS1 inhibitor. In phase 2b cohort 1, the objective response rate was 88% (95% CI 76-95; 49 of 56 patients). In a prespecified exploratory analysis in 41 patients with CNS metastases at baseline, the objective response rate was 100% (95% CI 48-100; five of five patients) in patients in phase 2a who were ROS1 inhibitor naive, 40% (16-68; six of 15) in patients in phase 2a who had previously received ROS1 inhibitor, and 90% (70-99; 19 of 21) in patients in phase 2b cohort 1. Grade 3-4 treatment-related adverse events occurred in 33 (32%) of 104 patients; the most common were hyperglycaemia (12 [12%] patients) and electrocardiogram prolonged QT interval (six [6%]). Serious treatment-related adverse events occurred in 11 (11%) patients, with hyperglycaemia (six [6%]) being most common. No treatment-related adverse events led to death. INTERPRETATION: Foritinib showed systemic and intracranial antitumour activity and good tolerability in ROS1-inhibitor-naive patients with ROS1-rearranged NSCLC. Foritinib represents a promising treatment for these patients, especially in those with CNS metastases. FUNDING: Fosun Pharma, Wanbang Biopharmaceuticals, and Guangdong Provincial Key Lab of Translational Medicine in Lung Cancer.

Human transferrin receptor can mediate SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been detected in almost all organs of coronavirus disease-19 patients, although some organs do not express angiotensin-converting enzyme-2 (ACE2), a known receptor of SARS-CoV-2, implying the presence of alternative receptors and/or co-receptors. Here, we show that the ubiquitously distributed human transferrin receptor (TfR), which binds to diferric transferrin to traffic between membrane and endosome for the iron delivery cycle, can ACE2-independently mediate SARS-CoV-2 infection. Human, not mouse TfR, interacts with Spike protein with a high affinity (KD ~2.95 nM) to mediate SARS-CoV-2 endocytosis. TfR knock-down (TfR-deficiency is lethal) and overexpression inhibit and promote SARS-CoV-2 infection, respectively. Humanized TfR expression enables SARS-CoV-2 infection in baby hamster kidney cells and C57 mice, which are known to be insusceptible to the virus infection. Soluble TfR, Tf, designed peptides blocking TfR-Spike interaction and anti-TfR antibody show significant anti-COVID-19 effects in cell and monkey models. Collectively, this report indicates that TfR is a receptor/co-receptor of SARS-CoV-2 mediating SARS-CoV-2 entry and infectivity by likely using the TfR trafficking pathway.

Rational Design of a Potent Antimicrobial Peptide Based on the Active Region of a Gecko Cathelicidin.

The emergence of multidrug-resistant (MDR) bacteria presents a significant challenge to public health, increasing the risk of infections that are resistant to current antibiotic treatment. Antimicrobial peptides (AMPs) offer a promising alternative to conventional antibiotics in the prevention of MDR bacterial infections. In the present study, we identified a novel cathelicidin AMP from Gekko japonicus, which exhibited broad-spectrum antibacterial activity against both Gram-negative and Gram-positive bacteria, with minimal inhibitory concentrations ranging from 2.34 to 4.69 µg/mL. To improve its potential therapeutic application, a series of peptides was synthesized based on the active region of the gecko-derived cathelicidin. The lead peptide (RH-16) showed an antimicrobial activity comparable to that of the parent peptide. Structural characterization revealed that RH-16 adopted an amphipathic α-helical conformation. Furthermore, RH-16 demonstrated neither hemolytic nor cytotoxic activity but effectively killed a wide range of clinically isolated, drug-resistant bacteria. The antimicrobial activity of RH-16 was attributed to the nonspecific targeting of bacterial membranes, leading to rapid bacterial membrane permeabilization and rupture. RH-16 also retained its antibacterial activity in plasma and exhibited mild toxicity in vivo. Notably, RH-16 offered robust protection against skin infection in a murine model. Therefore, this newly identified cathelicidin AMP may be a strong candidate for future pharmacological development targeting multidrug resistance. The use of a rational design approach for isolating the minimal antimicrobial unit may accelerate the transition of natural AMPs to clinically applicable antibacterial agents.

Transferrin Is Up-Regulated by Microbes and Acts as a Negative Regulator of Immunity to Induce Intestinal Immunotolerance.

Cross-talks (e.g., host-driven iron withdrawal and microbial iron uptake between host gastrointestinal tract and commensal microbes) regulate immunotolerance and intestinal homeostasis. However, underlying mechanisms that regulate the cross-talks remain poorly understood. Here, we show that bacterial products up-regulate iron-transporter transferrin and transferrin acts as an immunosuppressor by interacting with cluster of differentiation 14 (CD14) to inhibit pattern recognition receptor (PRR) signaling and induce host immunotolerance. Decreased intestinal transferrin is found in germ-free mice and human patients with ulcerative colitis, which are characterized by impaired intestinal immunotolerance. Intestinal transferrin and host immunotolerance are returned to normal when germ-free mice get normal microbial commensalism, suggesting an association between microbial commensalism, transferrin, and host immunotolerance. Mouse colitis models show that transferrin shortage impairs host's tolerogenic responses, while its supplementation promotes immunotolerance. Designed peptide blocking transferrin-CD14 interaction inhibits immunosuppressive effects of transferrin. In monkeys with idiopathic chronic diarrhea, transferrin shows comparable or even better therapeutic effects than hydrocortisone. Our findings reveal that by up-regulating host transferrin to silence PRR signaling, commensal bacteria counteract immune activation induced by themselves to shape host immunity and contribute for intestinal tolerance.

SRRM2 may be a potential biomarker and immunotherapy target for multiple myeloma: a real-world study based on flow cytometry detection.

Serine/arginine repetitive matrix 2 (SRRM2) has been implicated in tumorigenesis, cancer development, and drug resistance through aberrant splicing; however, its correlation with multiple myeloma (MM) has not been reported. We investigated the potential of SRRM2 as a biomarker and immunotherapeutic target in MM by examining its expression in MM cells using flow cytometry. Our study included 95 patients with plasma cell disease, including 80 MM cases, and we detected SRRM2 expression on plasma cells and normal blood cells to analyze its relationship with clinical profiles. We found widespread positive expression of SRRM2 on plasma cells with little expression on normal blood cells, and its expression on abnormal plasma cells was higher than that on normal plasma cells. Comparative analysis with clinical data suggests that SRRM2 expression on plasma cells correlates with MM treatment response. MM patients with high SRRM2 expression had higher levels of serum ß2-mg and LDH, ISS staging, and plasma cell infiltration, as well as high-risk mSMART 3.0 stratification and cytogenetic abnormalities, particularly 1q21 amplification. In patients with previous MM, high SRRM2 expression on plasma cells was associated with higher plasma cell infiltration, high-risk mSMART 3.0 risk stratification, cytogenetic abnormalities, more relapses, and fewer autologous stem cell transplant treatments. In summary, SRRM2 may serve as a novel biomarker and immunotherapeutic target for MM. Its expression level on plasma cells can help in risk stratification of MM and monitoring of treatment response.

Orientational Nanoconjugation with Gold Endows Marked Antimicrobial Potential and Drugability of Ultrashort Dipeptides.

Antibiotic resistance is a global threat. Antimicrobial peptides (AMPs) are highly desirable to treat multidrug-resistant pathogen infection. However, few AMPs are clinically available, due to high cost, instability, and poor selectivity. Here, ultrashort AMPs (2-3 residues with an N-terminal cysteine) are designed and assembled as gold nanoparticles. Au-S conjugation and ultrashort size restrict nonspecific reactions and peptide orientation, thus concentrating positively charged residues on the surface. The nanostructured assemblies enormously enhance antimicrobial abilities by 1000-6000-fold and stability. One representative (Au-Cys-Arg-NH2, Au_CR) shows selective antibacterial activity against Staphylococcus aureus with 10 nM minimal inhibitory concentration. Au_CR has comparable or better in vivo antimicrobial potency than vancomycin and methicillin, with low propensity to induce resistance, little side effects, and high stability (17.5 h plasma half-life). Au_CR acts by inducing collapse of membrane potential and rupture of the bacterial membrane. The report provides insights for developing AMP-metal nanohybrids, particularly tethering nonspecific reactions and AMP orientation on the metal surface.