Identification and characterization of a novel peptide ligand of epidermal growth factor receptor for targeted delivery of therapeutics

Investigating the anticancer effect of purified rCec-B peptide in a DEN murine model: Insights into tumorigenesis prevention, bioavailability, and molecular mechanisms

BACKGROUND

Anticancer peptides (ACPs) are considered cancer therapeutic candidates through decreasing tumor cell proliferation, migration, and angiogenesis.

OBJECTIVES

Determine the therapeutic potential of purified recombinant cecropin-B (rCec-B) peptide in vivo on HCC murine model and its effect, particularly on the activation of apoptotic pathways.

METHODS

Intact mass analysis of rCec-B was confirmed using mass spectrometry, molecular docking on epidermal growth factor receptor (EGFR) apoptosis was studied, and an in vivo acute toxicity study, followed by establishing the HCC model using diethylnitrosamine (DEN) was performed. Biochemical, molecular, and immunohistochemical parameters were detected in serum and liver samples.

RESULTS

A molecular docking study on EGFR showed a predicted binding model of rCec-B as a ligand with a high binding affinity equal to -50.167 kcal/mol. The peptide showed remarkable safety in the studied high doses. The liver of the HCC untreated model had a distorted lobular pattern with minimal to mild nuclear atypia. In HCC treated with rCec-B, liver sections had periportal inflammation, hydropic degeneration with focal cholestasis, and apoptotic hepatocellular bodies. Molecular detection and immunohistochemical analysis showed an upregulation of the oncogenic marker, Bcl-2, and a downregulation of apoptotic markers (FAS, FAS-L, Cas-8, BAX, and BID) in the untreated DEN group. Treated groups had a significant increase in all the detected apoptotic markers.

CONCLUSION

This study sheds light on the potential rCec-B's role in suppressing HCC progression. Hence, this peptide could be considered a promising therapeutic drug alone or in combination with other drugs to alleviate HCC treatment.

Peptide-Drug Conjugates as Next-Generation Therapeutics: Exploring the Potential and Clinical Progress

Peptide-drug conjugates (PDCs) have emerged as a next-generation therapeutic platform, combining the target specificity of peptides with the pharmacological potency of small-molecule drugs. As an evolution beyond antibody-drug conjugates (ADCs), PDCs offer distinct advantages, including enhanced cellular permeability, improved drug selectivity, and versatile design flexibility. This review provides a comprehensive analysis of the fundamental components of PDCs, including homing peptide selection, linker engineering, and payload optimization, alongside strategies to address their inherent challenges, such as stability, bioactivity, and clinical translation barriers. Therapeutic applications of PDCs span oncology, infectious diseases, metabolic disorders, and emerging areas like COVID-19, with several conjugates advancing in clinical trials and achieving regulatory milestones. Innovations, including bicyclic peptides, supramolecular architectures, and novel linker technologies, are explored as promising avenues to enhance PDC design. Additionally, this review examines the clinical trajectory of PDCs, emphasizing their therapeutic potential and highlighting ongoing trials that exemplify their efficacy. By addressing limitations and leveraging emerging advancements, PDCs hold immense promise as targeted therapeutics capable of addressing complex disease states and driving progress in precision medicine.

Peptide-modified nanoparticles for doxorubicin delivery: Strategies to overcome chemoresistance and perspectives on carbohydrate polymers

Chemotherapy serves as the primary treatment for cancers, facing challenges due to the emergence of drug resistance. Combination therapy has been developed to combat cancer drug resistance, yet it still suffers from lack of specific targeting of cancer cells and poor accumulation at the tumor site. Consequently, targeted administration of chemotherapy medications has been employed in cancer treatment. Doxorubicin (DOX) is one of the most frequently used chemotherapeutics, functioning by inhibiting topoisomerase activity. Enhancing the anti-cancer effects of DOX and overcoming drug resistance can be accomplished via delivery by nanoparticles. This review will focus on the development of peptide-DOX conjugates, the functionalization of nanoparticles with peptides, the co-delivery of DOX and peptides, as well as the theranostic use of peptide-modified nanoparticles in cancer treatment. The peptide-DOX conjugates have been designed to enhance the targeted delivery to cancer cells by interacting with receptors that are overexpressed on tumor surfaces. Moreover, nanoparticles can be modified with peptides to improve their uptake in tumor cells via endocytosis. Nanoparticles have the ability to co-deliver DOX along with therapeutic peptides for enhanced cancer treatment. Finally, nanoparticles modified with peptides can offer theranostic capabilities by facilitating both imaging and the delivery of DOX (chemotherapy).

Early Detection of Brain Metastases from Triple-Negative Breast Cancer with a Tumor-Targeting Dual-Modal MR/NIRF Imaging Probe

Objective

Imaging early-stage brain metastases from triple-negative breast cancer (TNBC) is challenging due to the blood-brain barrier (BBB). To address this issue, we developed Den-Angio-GE11, a nanoprobe engineered to traverse the BBB and selectively target metastatic cells.

Methods

A TNBC brain metastasis model was established in mice through intracardiac injection of MDA-MB-231 brain-seeking cells (MDA-MB-231-BR). Metastatic lesions were longitudinally monitored using T2-weighted magnetic resonance imaging (MRI) and confirmed through contrast-enhanced MRI with Gadolinium-DTPA (Gd-DTPA). The Den-Angio-GE11 nanoprobe was synthesized on a polyamidoamine (PAMAM)-G5 dendrimer platform, incorporating Angiopep-2 and GE11 peptides for BBB traversal and metastatic cell targeting. Dual-modal imaging capability was achieved by conjugating Gd-DTPA for MRI and NIR783 for near-infrared fluorescence (NIRF) imaging.

Results

Den-Angio-GE11 demonstrated significantly enhanced affinity to EGFR compared to controls, as confirmed by immunofluorescence staining and flow cytometry assays. Brain metastases appeared on T2-weighted MRI three weeks post-injection of MDA-MB-231BR cells and maintained uncompromised BBB function for another one or two weeks, as demonstrated by a lack of enhancement in Gd-DTPA-enhanced MRI. Compared to control nanoparticles, Den-Angio-GE11 remarkably enhanced T1 and NIRF signals of lesions after administration. Histological analysis confirmed Den-Angio-GE11 targeting brain metastatic cells. For lesions in extreme-early stage (undetectable by T2-weighted imaging), NIRF imaging post-Den-Angio-GE11 administration successfully indicated potential lesions. Fluorescence imaging analyses further verified Den-Angio-GE11 targeted sporadically metastatic cells in the brain parenchyma.

Conclusion

Early brain metastases of TNBC can be detected by Den-Angio-GE11 through T1-weighted MRI or NIRF imaging.

Peptide‑based therapeutic strategies for glioma: Current state and prospects

Glioma is a prevalent form of primary malignant central nervous system tumor, characterized by its cellular invasiveness, rapid growth, and the presence of the blood-brain barrier (BBB)/blood-brain tumor barrier (BBTB). Current therapeutic approaches, such as chemotherapy and radiotherapy, have shown limited efficacy in achieving significant antitumor effects. Therefore, there is an urgent demand for new treatments. Therapeutic peptides represent an innovative class of pharmaceutical agents with lower immunogenicity and toxicity. They are easily modifiable via chemical means and possess deep tissue penetration capabilities which reduce side effects and drug resistance. These unique pharmacokinetic characteristics make peptides a rapidly growing class of new therapeutics that have demonstrated significant progress in glioma treatment. This review outlines the efforts and accomplishments in peptide-based therapeutic strategies for glioma. These therapeutic peptides can be classified into four types based on their anti-tumor function: tumor-homing peptides, inhibitor/antagonist peptides targeting cell surface receptors, interference peptides, and peptide vaccines. Furthermore, we briefly summarize the results from clinical trials of therapeutic peptides in glioma, which shows that peptide-based therapeutic strategies exhibit great potential as multifunctional players in glioma therapy.

Spacer engineering in nanoparticle-peptide conjugates boosts targeting specificity for tumor-associated antigens

Developing and synthesizing nano-objects capable of enabling early targeted diagnosis and ensuring effective tumor treatment represents a significant challenge in the theranostic field. Among various nanoparticles (NPs), iron oxide nanoparticles (IONPs) have made significant contributions to advancing this field. However, a key challenge lies in achieving selective recognition of specific cell types. In oncology, the primary goal is to develop innovative strategies to enhance NP uptake by tumors, primarily through active targeting. This involves adding targeting ligands (TL) to the NP surface to facilitate tumor accumulation and increase retention within the tumor microenvironment. Despite biofunctionalization strategies, overall tumor uptake remains modest at only 5-7% of the injected dose per gram. In this work, we demonstrate the effect of spacing between the NPs and the TL to improve their availability and thus the tumor uptake of the complex. This proof-of-concept study targets the epidermal growth factor receptor (EGFR) using a peptide as a targeting ligand. Specifically, we characterized the PEG-peptide coupled to dendronized IONPs, including the density of grafted TL. These nano-objects underwent in vitro evaluation to assess their ability to specifically target and be internalized by tumor cells. Therapeutically, compared to non-functionalized NPs, the presence of the TL with a PEG linker enhanced targeting efficacy and increased internalization, leading to improved photothermal efficacy.

Targeted cancer treatment using a novel EGFR-specific Fc-fusion peptide based on GE11 peptide

Fc-fusion peptides, also known as peptibodies, are a promising new category of targeted therapeutics that offer alternatives to monoclonal antibodies (mAbs) for cancer treatment. This study focuses on an Fc-fusion peptide consisting of the Fc region of IgG1 and an epidermal growth factor receptor (EGFR)-targeting peptide, GE11, which was identified using the phage display method and demonstrated high affinity for the receptor. The fusion peptide (FcIgG-GE11) was successfully expressed in Escherichia coli and purified using ion-exchange chromatography. Flow cytometry confirmed its specific binding to EGFR. Like Cetuximab, the FcIgG-GE11 peptibody exhibited effective, dose- and time-dependent growth inhibition of EGFR-overexpressing cancer cell lines. Additionally, the results showed that the FcIgG-GE11 peptibody induced cell death or cycle arrest in certain cancer cell lines, with varying responses depending on the cancer type. The results of In-Cell ELISA when comparing the effects of the FcIgG-GE11 peptibody to Cetuximab on Tyr 1173 phosphorylation were similar. In addition, the relative potency of the FcIgG-GE11 peptibody compared to Cetuximab was assessed using the MTT results by Slope Ratio Analysis. These findings suggest that FcIgG-GE11 peptibody can provide a specific and efficient tool for both targeting and treating cancer cells.

A Conjugate of an EGFR-Binding Peptide and Doxorubicin Shows Selective Toxicity to Triple-Negative Breast Cancer Cells

Selective targeting of cancer cells via overexpressed cell-surface receptors is a promising strategy to enhance chemotherapy efficacy and minimize off-target side effects. In this study, we designed peptide 31 (YHWYGYTPERVI) to target the overexpressed epidermal growth factor receptor (EGFR) in triple-negative breast cancer (TNBC) cells. Peptide 31 is internalized by TNBC cells through EGFR-mediated endocytosis and shares sequence and structural similarities with human EGF (hEGF), a natural EGFR ligand. Unlike hEGF, peptide 31 does not induce cell migration in TNBC cells. A novel conjugate of peptide 31 with doxorubicin (Dox) retains selectivity for TNBC cells and exhibits significant toxicity comparable to that of unconjugated Dox. Importantly, this conjugate shows no toxicity toward normal breast epithelial cells up to a high concentration (25 μM). Thus, peptide 31 serves as a versatile targeting ligand for developing novel conjugates with high selectivity for EGFR-positive cancers.

Radiocobalt-Labeling of a Polypyridylamine Chelate Conjugated to GE11 for EGFR-Targeted Theranostics

The overexpression of the epidermal growth factor receptor (EGFR) in certain types of prostate cancers and glioblastoma makes it a promising target for targeted radioligand therapy. In this context, pairing an EGFR-targeting peptide with the emerging theranostic pair comprising the Auger electron emitter cobalt-58m (58mCo) and the Positron Emission Tomography-isotope cobalt-55 (55Co) would be of great interest for creating novel radiopharmaceuticals for prostate cancer and glioblastoma theranostics. In this study, GE11 (YHWYGYTPQNVI) was investigated for its EGFR-targeting potential when conjugated using click chemistry to N1-((triazol-4-yl)methyl)-N1,N2,N2-tris(pyridin-2-ylmethyl)ethane-1,2-diamine (TZTPEN). This chelator is suitable for binding Co2+ and Co3+. With cobalt-57 (57Co) serving as a surrogate radionuclide for 55/58mCo, the novel GE11-TZTPEN construct was successfully radiolabeled with a high radiochemical yield (99%) and purity (>99%). [57Co]Co-TZTPEN-GE11 showed high stability in PBS (pH 5) and specific uptake in EGFR-positive cell lines. Disappointingly, no tumor uptake was observed in EGFR-positive tumor-bearing mice, with most activity being accumulated predominantly in the liver, gall bladder, kidneys, and spleen. Some bone uptake was also observed, suggesting in vivo dissociation of 57Co from the complex. In conclusion, [57Co]Co-TZTPEN-GE11 shows poor pharmacokinetics in a mouse model and is, therefore, not deemed suitable as a targeting radiopharmaceutical for EGFR.

Theranostics Advances in the Treatment and Diagnosis of Neurological and Neurosurgical Diseases

Theranostics represents a significant advance in the fields of neurology and neurosurgery, offering innovative approaches that combine the diagnosis and treatment of various neurological disorders. This innovation serves as a cornerstone of personalized medicine, where therapeutic strategies are closely integrated with diagnostic tools to enable precise and targeted interventions. Primary research results emphasize the profound impact of theranostics in Neuro Oncol. In this context, it has provided valuable insights into the complexity of the tumor microenvironment and mechanisms of resistance. In addition, in the field of neurodegenerative diseases (NDs), theranostics has facilitated the identification of distinct disease subtypes and novel therapeutic targets. It has also unravelled the intricate pathophysiology underlying conditions such as cerebrovascular disease (CVD) and epilepsy, setting the stage for more refined treatment approaches. As theranostics continues to evolve through ongoing research and refinement, its goals include further advancing the field of precision medicine, developing practical biomarkers for clinical use, and opening doors to new therapeutic opportunities. Nevertheless, the integration of these approaches into clinical settings presents challenges, including ethical considerations, the need for advanced data interpretation, standardization of procedures, and ensuring cost-effectiveness. Despite these obstacles, the promise of theranostics to significantly improve patient outcomes in the fields of neurology and neurosurgery remains a source of optimism for the future of healthcare.

Metabolic Nanoregulators Induce Ferroptosis and Change Metabolite Flow to Reverse Immunosuppressive Tumor Microenvironment

Aberrant energy and substance metabolic pathways of tumor cells critically support tumor cell proliferation by hijacking the resources from nonmalignant cells, thereby establishing a metabolite flow favorable to tumor progression. This metabolic adaptation of tumor cells further modulates the immune landscape, ultimately creating a tumor microenvironment characterized by drug resistance and immunosuppression. The synergistic regulation of energy and substance metabolic pathways might be a good antitumor therapeutic paradigm. However, due to the metabolic convergence, it is crucial to selectively modulate the aberrant metabolism of tumor cells without compromising the functionality of other cells. Small-molecule drugs have the ability to target a wide range of biomolecules for antitumor therapy, but their application is limited by undesirable toxicities. Constructing nanodrug delivery systems can improve their properties and allow for the inclusion of multiple drugs, thereby exerting synergistic antitumor effects. In this study, we developed a two-drug codelivery system using drugs-conjugated multibranched polymers to modulate tumor cell metabolism by exploiting synthetic lethal pathways for safe and effective antitumor therapy. By delivery of adapalene and erastin simultaneously through nanoparticles, the material and energy metabolism of tumor cells can be regulated. This nanoparticle construction achieves tumor tissue targeting and responsive drug release, alters metabolite flow within tumor cells, and effectively kills tumor cells. Additionally, the nanoparticles can reverse the tumor immunosuppressive microenvironment, starting from single-cell regulation to whole-lesion control.

Peptides for microbe-induced cancers: latest therapeutic strategies and their advanced technologies

Cancer is a significant global health concern associated with multiple distinct factors, including microbial and viral infections. Numerous studies have elucidated the role of microorganisms, such as Helicobacter pylori (H. pylori), as well as viruses for example human papillomavirus (HPV), hepatitis B virus (HBV), and hepatitis C virus (HCV), in the development of human malignancies. Substantial attention has been focused on the treatment of these microorganism- and virus-associated cancers, with promising outcomes observed in studies employing peptide-based therapies. The current paper provides an overview of microbe- and virus-induced cancers and their underlying molecular mechanisms. We discuss an assortment of peptide-based therapies which are currently being developed, including tumor-targeting peptides and microbial/viral peptide-based vaccines. We describe the major technological advancements that have been made in the design, screening, and delivery of peptides as anticancer agents. The primary focus of the current review is to provide insight into the latest research and development in this field and to provide a realistic glimpse into the future of peptide-based therapies for microbe- and virus-induced neoplasms.

Fluorescent labeling of live-cell surfaceome and its application in antibody-target interaction analysis

BACKGROUND

Cell-surface proteins play key roles in the communication between external stimuli and internal signaling. As protein types and expression levels vary in different cells, in-situ visualization of the whole surface proteome (surfaceome) may facilitate the study of their functions in homeostasis maintenance or response to environmental changes (e.g., drug treatment). However, there lacks easily-prepared and universal labeling probes to visualize them in living cells.

RESULTS

We designed and synthesized a small-molecule fluorescent probe, SRB-NHS, for one-step labeling of surfaceome. Live-cell imaging results exhibited the plasma membrane localization of the fluorescent signal from SRB-NHS and SDS-PAGE/fluorescence scanning results confirmed the covalent labeling of proteins by SRB-NHS, indicating the suitability of SRB-NHS for surfaceome labeling towards different cell lines.

SIGNIFICANCE

Upon labeling by SRB-NHS, the cellular internalization of surfaceome was studied under different stimuli (e.g., nutritional deprivation, drug treatments). Intriguingly, specific monitoring of the interaction between antibody drugs and related cell-surface targets can be achieved when the probe is used in combination with fluorescently labeled antibodies and imaged via Förster resonance energy transfer (FRET), offering a new method compatible with various cell lines to monitor the surfaceome or a specific drug-target interaction in situ.

Engineered extracellular vesicles with polypeptide for targeted delivery of doxorubicin against EGFR‑positive tumors

Lack of effective tumor‑specific delivery systems remains an unmet clinical challenge for the employment of chemotherapy using cytotoxic drugs. Extracellular vesicles (EVs) have recently been investigated for their potential as an efficient drug‑delivery platform, due to their good biodistribution, biocompatibility and low immunogenicity. In the present study, the formulation of GE11 peptide‑modified EVs (GE11‑EVs) loaded with doxorubicin (Dox‑GE11‑EVs), was developed to target epidermal growth factor receptor (EGFR)‑positive tumor cells. The results obtained demonstrated that GE11‑EVs exhibited highly efficient targeting and drug delivery to EGFR‑positive tumor cells compared with non‑modified EVs. Furthermore, treatment with Dox‑GE11‑EVs led to a significantly inhibition of cell proliferation and increased apoptosis of EGFR‑positive tumor cells compared with Dox‑EVs and free Dox treatments. In addition, it was observed that treatment with either free Dox or Dox‑EVs exhibited a high level of cytotoxicity to normal cells, whereas treatment with Dox‑GE11‑EVs had only a limited effect on cell viability of normal cells. Taken together, the findings of the present study demonstrated that the engineered Dox‑GE11‑EVs can treat EGFR‑positive tumors more accurately and have higher safety than traditional tumor therapies.

Targeted nanoliposomes of oncogenic protein degraders: Significant inhibition of tumor in lung-cancer bearing mice

With 60 % of non-small cell lung cancer (NSCLC) expressing epidermal growth factor receptor (EGFR), it has been explored as an important therapeutic target for lung tumors. However, even the well-established EGFR inhibitors tend to promptly develop resistance over time. Moreover, strategies that could impede resistance development and be advantageous for both EGFR-Tyrosine kinase inhibitor (TKI)-sensitive and mutant NSCLC patients are constrained. Based on the critical relationship between EGFR, c-MYC, and Kirsten rat sarcoma virus (K-Ras), simultaneous degradation of EGFR and Bromodomain-containing protein 4 (BRD4) using "Proteolysis Targeting Chimeras (PROTACs)" could be a promising approach. PROTACs are emerging class of oncoprotein degraders but very challanging to deliver in vivo. Compared to individual IC50s, strong synergism was observed at 1:1 ratio of BPRO and EPRO in NSCLC cell lines with diverse mutation. Significant inhibition of cell growth with higher cellular apoptosis was observed in 2D and 3D-based cell assays in nanomolar concentrations. EGFR activation assay revealed 47.60 % EGFR non-expressing cells confirming EGFR-degrading potential of EPRO. A lung cancer specific nanoliposomal formulation of EGFR and BRD4-degrading PROTACs (EPRO and BPRO) was prepared and characetrized. Successful encapsulation of the two highly lipophilic molecules was achieved in EGFR-targeting nanoliposomal carriers (T-BEPRO) using a modified hydration technique. T-BEPRO revealed a particle size of 109.22 ± 0.266 nm with enhanced cellular uptake and activity. Remarkably, parenterally delivered T-BEPRO in tumor-bearing mice showed a substantially higher % tumor growth inhibition (TGI) of 77.6 % with long-lasting tumor inhibitory potential as opposed to individual drugs.

Smart Accumulating Dual-Targeting Lipid Envelopes Equipping Oncolytic Adenovirus for Enhancing Cancer Gene Therapeutic Efficacy

Systemic delivery of oncolytic adenovirus (oAd) for cancer gene therapy must overcome several limitations such as rapid clearance from the blood, nonspecific accumulation in the liver, and insufficient delivery to the tumor tissues. In the present report, a tumor microenvironment-triggered artificial lipid envelope composed of a pH-responsive sulfamethazine-based polymer (PUSSM)-conjugated phospholipid (DOPE-HZ-PUSSM) and another lipid decorated with epidermal growth factor receptor (EGFR) targeting peptide (GE11) (GE11-DOPE) was utilized to encapsulate replication-incompetent Ad (dAd) or oAd coexpressing short-hairpin RNA (shRNA) against Wnt5 (shWnt5) and decorin (dAd/LP-GE-PS or oAd/LP-GE-PS, respectively). In vitro studies demonstrated that dAd/LP-GE-PS transduced breast cancer cells in a pH-responsive and EGFR-specific manner, showing a higher level of transduction than naked Ad under a mildly acidic pH of 6.0 in EGFR-positive cell lines. In vivo biodistribution analyses revealed that systemic administration of oAd/LP-GE-PS leads to a significantly higher level of intratumoral virion accumulation compared to naked oAd, oAd encapsulated in a liposome without PUSSM or EGFR targeting peptide moiety (oAd/LP), or oAd encapsulated in a liposome with EGFR targeting peptide alone (oAd/LP-GE) in an EGFR overexpressing MDA-MB-468 breast tumor xenograft model, showing that both pH sensitivity and EGFR targeting ability were integral to effective systemic delivery of oAd. Further, systemic administration of all liposomal oAd formulations (oAd/LP, oAd/LP-GE, and oAd/LP-GE-PS) showed significantly attenuated hepatic accumulation of the virus compared to naked oAd. Collectively, our findings demonstrated that pH-sensitive and EGFR-targeted liposomal systemic delivery of oAd can be a promising strategy to address the conventional limitations of oAd to effectively treat EGFR-positive cancer in a safe manner.

Preliminary exploration of the anti-ovarian cancer activity of peptides derived from bovine bone collagen hydrolysate and its related mechanisms

Ovarian cancer, a malignant tumor that poses a significant threat to women's health, has seen a rise in incidence, prompting the urgent need for more effective treatment. This study primarily aimed to explore the potential of bovine collagen peptides in inhibiting ovarian cancer. The investigation in this study began with the identification of 268 peptide sequences through LC-MS/MS, followed by a screening process using molecular docking techniques to identify potential peptides capable of binding to EGFR. Subsequently, a series of experiments were performed, demonstrating the inhibitory effects of the peptide GPAGADGDRGEAGPAGPAGPAGPR on the proliferation of ovarian cancer cells. Transcriptomic analysis further revealed that this peptide can regulate cholesterol metabolism in ovarian cancer cells. Finally, a combination of time-resolved fluorescence resonance energy transfer, isothermal titration calorimetry, molecular docking, and molecular dynamics simulations were utilized to validate the ability of this peptide to bind to the epidermal growth factor receptor (EGFR) and impede the binding of epidermal growth factor (EGF) and EGFR.

Development of injectable upconversion nanoparticle-conjugated doxorubicin theranostics electrospun nanostructure for targeted photochemotherapy in breast cancer

Nanotheranostic-based photochemotherapies with targeted drug delivery have considerably surfaced in cancer therapy. In the presented work, polyethyleneimine-coated upconversion nanoparticles were engineered to conjugate covalently with doxorubicin. Upconversion nanoparticles (UCNP)-Doxorubicin (DOX)/synthesized epidermal growth factor receptor-targeting peptide blended with polymer composite was electrospun and formulated as the injectable dosage form. The size of the UCNP and the nanofiber diameter were assessed as 26.75 ± 1.54 and 162 ± 2.82 nm, respectively. The optimized ratio of dopants resulted in UCNP photoluminescence with maximum emission intensity at around 800 nm upon 980 nm excitation wavelength. The paramagnetic nature of UCNPs and amide conjugation with the drug was confirmed analytically. The loading capacity of UCNP for doxorubicin was determined to be 54.56%, while nanofibers exhibited 98.74% capacity to encapsulate UCNP-DOX. The release profile of UCNP-DOX from nanofiber formulation ranged from sustained to controlled, with relative enhancement in acidic conditions. The nanofiber demonstrated good mechanical strength, robust swelling, and degradation rate. Biocompatibility tests showed more than 90% cell viability on L929 and NIH/3T3 cell lines with UCNP-DOX@NF/pep nanoformulation. The IC50 values of 2.15 ± 0.54, 2.87 ± 0.67, and 3.42 ± 0.45 μg/mL on MDA-MB-231, 4T1, and MCF-7 cancer cell line, respectively, with a significant cellular uptake, has been reported. The UCNP protruded a ≈62.7°C temperature rise within 5 min of 980 nm laser irradiation and a power density of 0.5 W cm-2. The nanoformulation induced reactive oxygen species of 65.67% ± 3.21% and apoptosis by arresting the cell cycle sub-G1 phase. The evaluation conveys the effectiveness of the developed injectable theranostic delivery system in cancer therapy.

Use of a Cyclic α-Alkylidene-β-Diketone as a Cleavable Linker Strategy for Antibody-Drug Conjugates

In the fast-evolving landscape of targeted cancer therapies, the revolutionary class of biotherapeutics known as antibody-drug conjugates (ADCs) are taking center stage. Most clinically approved ADCs utilize cleavable linkers to temporarily attach potent cytotoxic payloads to antibodies, allowing selective payload release under tumor-specific conditions. In this study, we explored the utilization of 1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde), a cyclic β-diketone featuring an active alkylidene group, to develop a novel chemically labile linker. This linker was designed to exploit the difference in reduction potential between the intracellular compartment and plasma. Upon reduction of an azido trigger strategically installed neighboring the cyclic β-diketone, the resulting nucleophilic primary amine reacts with the alkylidene group facilitated by a favorable ring closure reaction in accordance with Baldwin's rules. Consequently, this reaction enables the simultaneous release of the attached cytotoxic payload. The therapeutic utility of this novel linker strategy was demonstrated by separate conjugation of the linker to two epidermal growth factor receptor (EGFR)-targeting ligands to afford a peptide-drug conjugate and an ADC. This work comprises a significant contribution to the bioconjugation field by introducing the alkylidene cyclic β-diketone as a tunable scaffold used for the temporary conjugation of therapeutic agents to peptides and proteins.

Aptamer-Based Enforced Phosphatase-Recruiting Chimeras Inhibit Receptor Tyrosine Kinase Signal Transduction

Aberrant phosphorylation of receptor tyrosine kinases (RTKs) is usually involved in tumor initiation, progression, and metastasis. However, developing specific and efficient molecular tools to regulate RTK phosphorylation remains a considerable challenge. In this study, we reported novel aptamer-based chimeras to inhibit the phosphorylation of RTKs, such as c-Met and EGFR, by enforced recruitment of a protein tyrosine phosphatase receptor type F (PTPRF). Our studies revealed that aptamer-based chimeras displayed a generic and potent inhibitory effect on RTK phosphorylation induced by growth factor or auto-dimerization in different cell lines and modulated cell biological behaviors by recruiting PTPRF. Furthermore, based on angstrom accuracy of the DNA duplex, the maximum catalytic radius of PTPRF was determined as ∼25.84 nm, providing a basis for the development of phosphatase-recruiting strategies. Taken together, our study provides a generic methodology not only for selectively mediating RTK phosphorylation and cellular biological processes but also for developing novel therapeutic drugs.

EGFR- and Integrin αVβ3-Targeting Peptides as Potential Radiometal-Labeled Radiopharmaceuticals for Cancer Theranostics

The burgeoning field of cancer theranostics has witnessed advancements through the development of targeted molecular agents, particularly peptides. These agents exploit the overexpression or mutations of specific receptors, such as the Epidermal Growth Factor receptor (EGFR) and αVβ3 integrin, which are pivotal in tumor growth, angiogenesis, and metastasis. Despite the extensive research into and promising outcomes associated with antibody-based therapies, peptides offer a compelling alternative due to their smaller size, ease of modification, and rapid bioavailability, factors which potentially enhance tumor penetration and reduce systemic toxicity. However, the application of peptides in clinical settings has challenges. Their lower binding affinity and rapid clearance from the bloodstream compared to antibodies often limit their therapeutic efficacy and diagnostic accuracy. This overview sets the stage for a comprehensive review of the current research landscape as it relates to EGFR- and integrin αVβ3-targeting peptides. We aim to delve into their synthesis, radiolabeling techniques, and preclinical and clinical evaluations, highlighting their potential and limitations in cancer theranostics. This review not only synthesizes the extant literature to outline the advancements in peptide-based agents targeting EGFR and integrin αVβ3 but also identifies critical gaps that could inform future research directions. By addressing these gaps, we contribute to the broader discourse on enhancing the diagnostic precision and therapeutic outcomes of cancer treatments.

Extracellular Vesicles as Drug Delivery System for Cancer Therapy

In recent decades, the pursuit of drug delivery systems has led to the development of numerous synthetic options aimed at enhancing drug efficacy while minimizing side effects. However, the practical application of these systems is often hindered by challenges such as inefficiency, cytotoxicity, and immunogenicity. Extracellular vesicles, natural carriers for drugs, emerge as promising alternatives with distinct advantages over synthetic carriers. Notably, EVs exhibit biocompatibility, low immunogenicity, and inherent tissue-targeting capabilities, thus opening new avenues for drug delivery strategies. This review provides an overview of EVs, including their biogenesis and absorption mechanisms. Additionally, we explore the current research efforts focusing on harnessing their potential as drug carriers, encompassing aspects such as purification techniques, drug loading, and bioengineering for targeted delivery. Finally, we discuss the existing challenges and future prospects of EVs as therapeutic agents in clinical settings. This comprehensive analysis aims to shed light on the potential of EVs as versatile and effective tools for drug delivery, particularly in the realm of cancer therapy.

Tailored Viral-like Particles as Drivers of Medical Breakthroughs

Despite the recognized potential of nanoparticles, only a few formulations have progressed to clinical trials, and an even smaller number have been approved by the regulatory authorities and marketed. Virus-like particles (VLPs) have emerged as promising alternatives to conventional nanoparticles due to their safety, biocompatibility, immunogenicity, structural stability, scalability, and versatility. Furthermore, VLPs can be surface-functionalized with small molecules to improve circulation half-life and target specificity. Through the functionalization and coating of VLPs, it is possible to optimize the response properties to a given stimulus, such as heat, pH, an alternating magnetic field, or even enzymes. Surface functionalization can also modulate other properties, such as biocompatibility, stability, and specificity, deeming VLPs as potential vaccine candidates or delivery systems. This review aims to address the different types of surface functionalization of VLPs, highlighting the more recent cutting-edge technologies that have been explored for the design of tailored VLPs, their importance, and their consequent applicability in the medical field.

Peptide-based non-viral gene delivery: A comprehensive review of the advances and challenges

Gene therapy is the most effective treatment option for diseases, but its effectiveness is affected by the choice and design of gene carriers. The genes themselves have to pass through multiple barriers in order to enter the cell and therefore require additional vectors to carry them inside the cell. In gene therapy, peptides have unique properties and potential as gene carriers, which can effectively deliver genes into specific cells or tissues, protect genes from degradation, improve gene transfection efficiency, and enhance gene targeting and biological responsiveness. This paper reviews the research progress of peptides and their derivatives in the field of gene delivery recently, describes the obstacles encountered by foreign materials to enter the interior of the cell, and introduces the following classes of functional peptides that can carry materials into the interior of the cell, and assist in transmembrane translocation of carriers, thus breaking through endosomal traps to enable successful entry of genetic materials into the nucleus of the cell. The paper also discusses the combined application of peptide vectors with other vectors to enhance its transfection ability, explores current challenges encountered by peptide vectors, and looks forward to future developments in the field.

Receptor-Targeted Dual pH-Triggered Intracellular Protein Transfer

Protein therapeutics are of widespread interest due to their successful performance in the current pharmaceutical and medical fields, even though their broad applications have been hindered by the lack of an efficient intracellular delivery approach. Herein, we fabricated an active-targeted dual pH-responsive delivery system with favorable tumor cell entry augmented by extracellular pH-triggered charge reversal and tumor receptor targeting and pH-controlled endosomal release in a traceless fashion. As a traceable model protein, the enhanced green fluorescent protein (eGFP) bearing a nuclear localization signal was covalently coupled with a pH-labile traceless azidomethyl-methylmaleic anhydride (AzMMMan) linker followed by functionalization with different molar equivalents of two dibenzocyclooctyne-octa-arginine-cysteine (DBCO-R8C)-modified moieties: polyethylene glycol (PEG)-GE11 peptide for epidermal growth factor receptor-mediated targeting and melittin for endosomal escape. The cationic melittin domain was masked with tetrahydrophthalic anhydride revertible at mild acidic pH 6.5. At the optimally balanced ratio of functional units, the on-demand charge conversion at tumoral extracellular pH 6.5 in combination with GE11-mediated targeting triggered enhanced electrostatic cellular attraction by the R8C cell-penetrating peptides and melittin, as demonstrated by strongly enhanced cellular uptake. Successful endosomal release followed by nuclear localization of the eGFP cargo was obtained by taking advantage of melittin-mediated endosomal escape and rapid traceless release from the AzMMMan linker. The effectiveness of this multifunctional bioresponsive system suggests a promising strategy for delivery of protein drugs toward intracellular targets. A possible therapeutic relevance was indicated by an example of cytosolic delivery of cytochrome c initiating the apoptosis pathway to kill cancer cells.

Unnatural Amino Acid Engineering for Intracellular Delivery of Protein Therapeutics

Protein drugs are a critically important therapeutic modality due to the sophisticated binding recognition, catalytic properties, and disease relevance of proteins. There is a clear need for new strategies able to improve pharmacokinetics, bioavailability, and/or intracellular delivery of therapeutic proteins, as stability limitations have significantly hindered clinical advancement, and most proteins are membrane impermeable. Bioconjugation strategies able to site-specifically modify proteins with cell binding, and other ligands offer a particularly valuable approach to facilitate protein delivery due to the importance of ligand presentation on protein bioactivity and cellular uptake. We explored unnatural amino acid (UAA) incorporation as a novel strategy to tunably incorporate clustered cell-binding ligands in fluorescent proteins and suicide enzymes, resulting in substantial increases in cell-specific uptake and targeted cell-killing activity. These approaches offer a valuable and versatile method to modify a variety of proteins and enable improved clinical potential.

Engineering Hepatitis B Virus (HBV) Protein Particles for Therapeutic Delivery

Nature provides an abundance of proteins whose structures and reactivity have been perfected through evolution to perform specific tasks necessary for biological function. The structural and functional properties of many natural proteins are quite valuable for the construction and customization of drug delivery vehicles. Self-assembling protein nanoparticle platforms are particularly useful scaffolds, as their multi-subunit designs allow the attachment of a high density of modifying molecules such as cell-binding ligands that provide avidity for targeting and facilitate encapsulation of large quantities of therapeutic payload. We explored SpyCatcher/SpyTag conjugation as a system to modify hepatitis B virus (HBV)-like particles (HBV VLPs). Using this simple decoration strategy, we demonstrated efficient and cell-selective killing of inflammatory breast cancer cells via delivery of yeast cytosine deaminase suicide enzymes combined with 5-fluoro-cytosine prodrugs.

Protocol for Delivery of CRISPR/dCas9 Systems for Epigenetic Editing into Solid Tumors Using Lipid Nanoparticles Encapsulating RNA

Genome editing tools, particularly the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) systems (e.g., CRISPR/Cas9), and their repurposing into epigenetic editing platforms, offer enormous potential as safe and customizable therapies for cancer. Specifically, various transcriptional abnormalities in human malignancies, such as silencing of tumor suppressors and ectopic re-expression of oncogenes, have been successfully targeted with virtually no off-target effects using CRISPR activation and repression systems. In these systems, the nuclease-deactivated Cas9 protein (dCas9) is fused to one or more domains inducing selective activation or repression of the targeted genes. Despite these advances, the efficient in vivo delivery of these molecules into the target cancer cells represents a critical barrier to accomplishing translation into a clinical therapy setting for cancer. Major obstacles include the large size of dCas9 fusion proteins, the necessity of multimodal delivery of protein and gRNAs, and the potential of these formulations to elicit detrimental immune responses.In this context, viral methods for delivering CRISPR face several limitations, such as the packaging capacity of the viral genome, the potential for integration of the nucleic acids into the host cells genome, and immunogenicity of viral proteins, posing serious safety concerns. The rapid development of mRNA vaccines in response to the COVID-19 pandemic has rekindled interest in mRNA-based approaches for CRISPR/dCas9 delivery. Simultaneously, due to their high loading capacity, scalability, customizable surface modification for cell targeting, and low immunogenicity, lipid nanoparticles (LNPs) have been widely explored as nonviral vectors. In this chapter, we first describe the design of optimized dCas9-effector mRNAs and gRNAs for epigenetic editing. We outline formulations of LNPs suitable for dCas9 mRNA delivery. Additionally, we provide a protocol for the co-encapsulation of the dCas9-effector mRNAs and gRNA into these LNPs, along with detailed methods for delivering these formulations to both cell lines (in vitro) and mouse models of breast cancer (in vivo).

Potential Application of Self-Assembled Peptides and Proteins in Breast Cancer and Cervical Cancer

Ongoing research is gradually broadening the idea of cancer treatment, with attention being focused on nanoparticles to improve the stability, therapeutic efficacy, targeting, and other important metrics of conventional drugs and traditional drug delivery methods. Studies have demonstrated that drug delivery carriers based on biomaterials (e.g., protein nanoparticles and lipids) and inorganic materials (e.g., metal nanoparticles) have potential anticancer effects. Among these carriers, self-assembled proteins and peptides, which are highly biocompatible and easy to standardize and produce, are strong candidates for the preparation of anticancer drugs. Breast cancer (BC) and cervical cancer (CC) are two of the most common and deadly cancers in women. These cancers not only threaten lives globally but also put a heavy burden on the healthcare system. Despite advances in medical care, the incidence of these two cancers, particularly CC, which is almost entirely preventable, continues to rise, and the mortality rate remains steady. Therefore, there is still a need for in-depth research on these two cancers to develop more targeted, efficacious, and safe therapies. This paper reviews the types of self-assembling proteins and peptides (e.g., ferritin, albumin, and virus-like particles) and natural products (e.g., soy and paclitaxel) commonly used in the treatment of BC and CC and describes the types of drugs that can be delivered using self-assembling proteins and peptides as carriers (e.g., siRNAs, DNA, plasmids, and mRNAs). The mechanisms (including self-assembly) by which the natural products act on CC and BC are discussed. The mechanism of action of natural products on CC and BC and the mechanism of action of self-assembled proteins and peptides have many similarities (e.g., NF-KB and Wnt). Thus, natural products using self-assembled proteins and peptides as carriers show potential for the treatment of BC and CC.

Development of light and pH-dual responsive self-quenching theranostic SPION to make EGFR overexpressing micro tumors glow and destroy

Drug resistant and undetectable tumors easily escape treatment leading metastases and/or recurrence of the lethal disease. Therefore, it is vital to diagnose and destroy micro tumors using simple yet novel approaches. Here, we present fluorescence-based detection and light-based destruction of cancer cells that are known to be resistant to standard therapies. We developed a superparamagnetic iron oxide nanoparticle (SPION)-based theranostic agent that is composed of self-quenching light activated photosensitizer (BPD) and EGFR targeting ligand (Anti-EGFR ScFv or GE11 peptide). Photosensitizer (BPD) was immobilized to PEG-PEI modified SPION with acid-labile linker. Prior to stimulation of the theranostic system by light its accumulation within cancer cells is vital since BPD phototoxicity and fluorescence is activated by lysosomal proteolysis. As BPD is cleaved, the system switches from off to on position which triggers imaging and therapy. Targeting, therapeutic and diagnostic features of the theranostic system were evaluated in high and moderate level EGFR expressing pancreatic cancer cell lines. Our results indicate that the system distinguishes high and moderate EGFR expression levels and yields up to 4.3-fold increase in intracellular fluorescence intensity. Amplification of fluorescence signal was as low as 1.3-fold in the moderate or no EGFR expressing cell lines. Anti-EGFR ScFv targeted SPION caused nearly 2-fold higher cell death via apoptosis in high EGFR expressing Panc-1 cell line. The developed system, possessing advanced targeting, enhanced imaging and effective therapeutic features, is a promising candidate for multi-mode detection and destruction of residual drug-resistant cancer cells.

Improving the efficacy of anti-EGFR drugs in GBM: Where we are going?

The therapies targeting mutations of driver genes in cancer have advanced into clinical trials for a variety of tumors. In glioblastoma (GBM), epidermal growth factor receptor (EGFR) is the most commonly mutated oncogene, and targeting EGFR has been widely investigated as a promising direction. However, the results of EGFR pathway inhibitors have not been satisfactory. Limited blood-brain barrier (BBB) permeability, drug resistance, and pathway compensation mechanisms contribute to the failure of anti-EGFR therapies. This review summarizes recent research advances in EGFR-targeted therapy for GBM and provides insight into the reasons for the unsatisfactory results of EGFR-targeted therapy. By combining the results of preclinical studies with those of clinical trials, we discuss that improved drug penetration across the BBB, the use of multi-target combinations, and the development of peptidomimetic drugs under the premise of precision medicine may be promising strategies to overcome drug resistance in GBM.

20 years since the approval of first EGFR-TKI, gefitinib: Insight and foresight

Epidermal growth factor receptor (EGFR) actively involves in modulation of various cancer progression related mechanisms including angiogenesis, differentiation and migration. Therefore, targeting EGFR has surfaced as a prominent approach for the treatment of several types of cancers, including non-small cell lung cancer (NSCLC), pancreatic cancer, glioblastoma. Various first, second and third generation of EGFR tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated effectiveness as an anti-cancer therapeutics. However, rapid development of drug resistance and mutations still remains a major challenge for the EGFR-TKIs therapy. Overcoming from intrinsic and acquired resistance caused by EGFR mutations warrants the further exploration of alternative strategies and discovery of novel inhibitors. In this review, we delve into the breakthrough discoveries have been made in previous 20 years, and discuss the currently ongoing efforts aimed to circumvent the chemo-resistance. We also highlight the new challenges, limitations and future directions for the development of improved therapeutic approaches such as fourth-generation EGFR-TKIs, peptides, nanobodies, PROTACs etc.

Exosome engineering for efficient and targeted drug delivery: Current status and future perspective

Exosomes are membrane-bound vesicles that are released by most cells. They carry nucleic acids, cytokines, growth factors, proteins, lipids, and metabolites. They are responsible for inter- and intracellular communications and their role in drug delivery is well defined. Exosomes have great potential for therapeutic applications, but the clinical use is restricted because of limitations in standardized procedures for isolation, purification, and drug delivery. Bioengineering of exosomes could be one approach to achieve standardization and reproducible isolation for clinical use. Exosomes are important transporters for targeted drug delivery because of their small size, stable structure, non-immunogenicity, and non-toxic nature, as well as their ability to carry a wide variety of compounds. These features of exosomes can be enhanced further by bioengineering. In this review, possible exosome bioengineering approaches, their biomedical applications, and targeted drug delivery are discussed.

Integrin αvβ3 and EGFR dual-targeted [64Cu]Cu-NOTA-RGD-GE11 heterodimer for PET imaging in pancreatic cancer mouse model

PURPOSE

Radiolabeled heterodimeric peptide has emerged as a highly promising targeting strategy for PET imaging due to their superior properties. RGD and GE11 are two peptides binding to receptor integrin αvβ3 and EGFR, respectively, which both overexpress in many different types of tumors. This study focuses on the synthesis and evaluation of a RGD and GE11-containing heterodimeric radiotracer [64Cu]Cu-NOTA-RGD-GE11 for PET imaging of tumors that simultaneously overexpress integrin αvβ3 and EGFR.

PROCEDURES

[64Cu]Cu-NOTA-RGD-GE11 was prepared by the conjugation of RGD-PEG4-NOTA-N3 and GE11-PEG4-BCN via metal-free click chemistry, followed by radiolabeling with 64Cu. Cell uptake and efflux studies, saturation binding assay, the animal PET/CT and biodistribution studies were conducted to characterize the biological properties of [64Cu]Cu-NOTA-RGD-GE11.

RESULTS

[64Cu]Cu-NOTA-RGD-GE11 was synthesized with a radiochemical purity of >97 % and molar activity of 23 GBq/μmol at the end of synthesis. [64Cu]Cu-NOTA-RGD-GE11 showed moderate hydrophilicity, good stability in mouse serum and high specific uptake by the human pancreatic cancer cell line (BxPC3) in the in vitro studies. Compared to the two monomeric counterparts [64Cu]Cu-NOTA-RGD and [64Cu]Cu-NOTA-GE11, [64Cu]Cu-NOTA-RGD-GE11 demonstrated significantly improved tumor uptakes (e.g. 4.63 ± 0.25 %ID/g vs 1.24 ± 0.18 %ID/g and 0.77 ± 0.13 %ID/g, 2 h after injection, p < 0.05) in the subsequent in vivo evaluation in mice bearing BxPC3 xenograft. Tumor uptake could be blocked in the presence of both non-radioactive c(RGDyK) and GE11 peptides, indicating good tumor specificity of [64Cu]Cu-NOTA-RGD-GE11 in vivo.

CONCLUSION

The results suggested that the as-developed [64Cu]Cu-NOTA-RGD-GE11 could serve as a potential PET tracer for the noninvasive imaging of integrin αvβ3 and EGFR expression in tumors.

Peptide Assemblies for Cancer Therapy

Supramolecular assemblies made by the self-assembly of peptides are finding an increasing number of applications in various fields. While the early exploration of peptide assemblies centered on tissue engineering or regenerative medicine, the recent development has shown that peptide assemblies can act as supramolecular medicine for cancer therapy. This review covers the progress of applying peptide assemblies for cancer therapy, with the emphasis on the works appeared over the last five years. We start with the introduction of a few seminal works on peptide assemblies, then discuss the combination of peptide assemblies with anticancer drugs. Next, we highlight the use of enzyme-controlled transformation or shapeshifting of peptide assemblies for inhibiting cancer cells and tumors. After that, we provide the outlook for this exciting field that promises new kind of therapeutics for cancer therapy.

Liver Cell Type-Specific Targeting by Nanoformulations for Therapeutic Applications

Hepatocytes exert pivotal roles in metabolism, protein synthesis and detoxification. Non-parenchymal liver cells (NPCs), largely comprising macrophages, dendritic cells, hepatic stellate cells and liver sinusoidal cells (LSECs), serve to induce immunological tolerance. Therefore, the liver is an important target for therapeutic approaches, in case of both (inflammatory) metabolic diseases and immunological disorders. This review aims to summarize current preclinical nanodrug-based approaches for the treatment of liver disorders. So far, nano-vaccines that aim to induce hepatitis virus-specific immune responses and nanoformulated adjuvants to overcome the default tolerogenic state of liver NPCs for the treatment of chronic hepatitis have been tested. Moreover, liver cancer may be treated using nanodrugs which specifically target and kill tumor cells. Alternatively, nanodrugs may target and reprogram or deplete immunosuppressive cells of the tumor microenvironment, such as tumor-associated macrophages. Here, combination therapies have been demonstrated to yield synergistic effects. In the case of autoimmune hepatitis and other inflammatory liver diseases, anti-inflammatory agents can be encapsulated into nanoparticles to dampen inflammatory processes specifically in the liver. Finally, the tolerance-promoting activity especially of LSECs has been exploited to induce antigen-specific tolerance for the treatment of allergic and autoimmune diseases.

EGFR-targeted semiconducting polymer nanoparticles for photoacoustic imaging

Semiconducting polymer nanoparticles (SPN), formulated from organic semiconducting polymers and lipids, show promise as exogenous contrast agents for photoacoustic imaging (PAI). To fully realise the potential of this class of nanoparticles for imaging and therapeutic applications, a broad range of active targeting strategies, where ligands specific to receptors on the target cells are displayed on the SPN surface, are urgently needed. In addition, effective strategies for quantifying the level of surface modification are also needed to support development of ligand-targeted SPN. In this paper, we have developed methods to prepare SPN bearing peptides targeted to Epidermal Growth Factor Receptors (EGFR), which are overexpressed at the surface of a wide variety of cancer cell types. In addition to fully characterising these targeted nanoparticles by standard methods (UV-visible, photoacoustic absorption, dynamic light scattering, zeta potential and SEM), we have developed a powerful new NMR method to determine the degree of conjugation and the number of targeting peptides attached to the SPN. Preliminary in vitro experiments with the colorectal cancer cell line LIM1215 indicated that the EGFR-targeting peptide conjugated SPN were either ineffective in delivering the SPN to the cells, or that the targeting peptide itself destabilised the formulation. This in reinforces the need for effective characterisation techniques to measure the surface accessibility of targeting ligands attached to nanoparticles.

Current research status of anti-cancer peptides: Mechanism of action, production, and clinical applications

The escalating rate of cancer cases, together with treatment deficiencies and long-term side effects of currently used cancer drugs, has made this disease a global burden of the 21st century. The number of breast and lung cancer patients has sharply increased worldwide in the last few years. Presently, surgical treatment, radiotherapy, chemotherapy, and immunotherapy strategies are used to cure cancer, which cause severe side effects, toxicities, and drug resistance. In recent years, anti-cancer peptides have become an eminent therapeutic strategy for cancer treatment due to their high specificity and fewer side effects and toxicity. This review presents an updated overview of different anti-cancer peptides, their mechanisms of action and current production strategies employed for their manufacture. In addition, approved and under clinical trials anti-cancer peptides and their applications have been discussed. This review provides updated information on therapeutic anti-cancer peptides that hold great promise for cancer treatment in the near future.

Dual Targeted Delivery of Liposomal Hybrid Gold Nano-Assembly for Enhanced Photothermal Therapy against Lung Carcinomas

The delivery and accumulation of therapeutic drugs into cancer cells without affecting healthy cells are a major challenge for antitumor therapy. Here, we report the synthesis of a liposomal hybrid gold nano-assembly with enhanced photothermal activity for lung cancer treatment. The core components of the nano-assembly include gold nanorods coated with a mesoporous silica shell that offers an excellent drug-loading surface for encapsulation of doxorubicin. To enhance the photothermal capacity of nano-assembly, IR 780 dye was loaded inside a thermo-sensitive liposome, and then, the core nano-assembly was wrapped within the liposome, and GE-11 peptide and folic acid were conjugated onto the surface of the liposome to give the final nano-assembly [(GM@Dox) LI]-PF. The dual targeting approach of [(GM@Dox) LI]-PF leads to enhanced cellular uptake and improves the accumulation of nano-assemblies in cancer cells that overexpress the epidermal growth factor receptor and folate. The exposure of near-infrared laser irradiation can trigger photothermal-induced structural disruption of the nano-assembly, which allows for the precise and controllable release of Dox at targeted sites. Additionally, chemo-photothermal therapy was shown to be 11 times more effective in cancer cell treatment when compared to Dox alone. Our systematic study suggests that the nano-assemblies facilitate the cancer cells undergoing apoptosis via an intrinsic mitochondrial pathway that can be directly triggered by the chemo-photothermal treatment. This study offers an appealing candidate that holds great promise for synergistic cancer treatment.

Development of Cyclic Peptides Targeting the Epidermal Growth Factor Receptor in Mesenchymal Triple-Negative Breast Cancer Subtype

Triple-negative breast cancer (TNBC) is an aggressive malignancy characterized by the lack of expression of estrogen and progesterone receptors and amplification of human epidermal growth factor receptor 2 (HER2). Being the Epidermal Growth Factor Receptor (EGFR) highly expressed in mesenchymal TNBC and correlated with aggressive growth behavior, it represents an ideal target for anticancer drugs. Here, we have applied the phage display for selecting two highly specific peptide ligands for targeting the EGFR overexpressed in MDA-MB-231 cells, a human TNBC cell line. Molecular docking predicted the peptide-binding affinities and sites in the extracellular domain of EGFR. The binding of the FITC-conjugated peptides to human and murine TNBC cells was validated by flow cytometry. Confocal microscopy confirmed the peptide binding specificity to EGFR-positive MDA-MB-231 tumor xenograft tissues and their co-localization with the membrane EGFR. Further, the peptide stimulation did not affect the cell cycle of TNBC cells, which is of interest for their utility for tumor targeting. Our data indicate that these novel peptides are highly specific ligands for the EGFR overexpressed in TNBC cells, and thus they could be used in conjugation with nanoparticles for tumor-targeted delivery of anticancer drugs.

Peptide-functionalized therapeutic nanoplatform for treatment orthotopic triple negative breast cancer and bone metastasis

Epidermal Growth Factor Receptor (EGFR) is a promising therapeutic target for triple-negative breast cancer (TNBC). Recently, specific EGFR-targeting peptide GE11-based delivery nano-system shows excellent potential because of its chemical versatility and good targeting ability. However, no further research focusing on the downstream of EGFR after binding with GE11 was explored. Hence, we tailor-designed a self-assembled nanoplatform named GENP using amphiphilic molecule of stearic acid-modified GE11. After loading doxorubicin (DOX), the resulted nanoplatform GENP@DOX demonstrated high loading efficiency and sustainable drug release. Importantly, our findings proved that GENP alone significantly suppressed the proliferation of MDA-MB-231 cells via EGFR-downstream PI3K/AKT signaling pathways, contributing to the synergistic treatment with its DOX release. Further work illustrated remarkable therapeutic efficacy both in orthotopic TNBC and its bone metastasis models with minimal biotoxicity. Together, the results highlight that our GENP-functionalized nanoplatform is a promising strategy for the synergistic therapeutic efficacy targeting EGFR-overexpressed cancer.

Recent Advances in Boosting EGFR Tyrosine Kinase Inhibitors-Based Cancer Therapy

Epidermal growth factor receptor (EGFR) plays a key role in signal transduction pathways associated with cell proliferation, growth, and survival. Its overexpression and aberrant activation in malignancy correlate with poor prognosis and short survival. Targeting inhibition of EGFR by small-molecular tyrosine kinase inhibitors (TKIs) is emerging as an important treatment model besides of chemotherapy, greatly reshaping the landscape of cancer therapy. However, they are still challenged by the off-targeted toxicity, relatively limited cancer types, and drug resistance after long-term therapy. In this review, we summarize the recent progress of oral, pulmonary, and injectable drug delivery systems for enhanced and targeting TKI delivery to tumors and reduced side effects. Importantly, EGFR-TKI-based combination therapies not only greatly broaden the applicable cancer types of EGFR-TKI but also significantly improve the anticancer effect. The mechanisms of TKI resistance are summarized, and current strategies to overcome TKI resistance as well as the application of TKI in reversing chemotherapy resistance are discussed. Finally, we provide a perspective on the future research of EGFR-TKI-based cancer therapy.

Innovative Diagnostic Peptide-Based Technologies for Cancer Diagnosis: Focus on EGFR-Targeting Peptides

Active targeting using biological ligands has emerged as a novel strategy for the targeted delivery of diagnostic agents to tumor cells. Conjugating functional targeting moieties with diagnostic probes can increase their accumulation in tumor cells and tissues, enhancing signal detection and, thus, the sensitivity of diagnosis. Due to their small size, ease of chemical synthesis and site-specific modification, high tissue penetration, low immunogenicity, rapid blood clearance, low cost, and biosafety, peptides offer several advantages over antibodies and proteins in diagnostic applications. Epidermal growth factor receptor (EGFR) is one of the most promising cancer biomarkers for actively targeting diagnostic and therapeutic agents to tumor cells due to its active involvement and overexpression in various cancers. Several peptides for EGFR-targeting have been identified in the last decades, which have been obtained by multiple means including derivation from natural proteins, phage display screening, positional scanning synthetic combinatorial library, and in silico screening. Many studies have used these peptides as a targeting moiety for diagnosing different cancers in vitro, in vivo, and in clinical trials. This review summarizes the progress of EGFR-targeting peptide-based assays in the molecular diagnosis of cancer.

Genetically Encoded Self-Assembling Protein Nanoparticles for the Targeted Delivery In Vitro and In Vivo

Targeted nanoparticles of different origins are considered as new-generation diagnostic and therapeutic tools. However, there are no targeted drug formulations within the composition of nanoparticles approved by the FDA for use in the clinic, which is associated with the insufficient effectiveness of the developed candidates, the difficulties of their biotechnological production, and inadequate batch-to-batch reproducibility. Targeted protein self-assembling nanoparticles circumvent this problem since proteins are encoded in DNA and the final protein product is produced in only one possible way. We believe that the combination of the endless biomedical potential of protein carriers as nanoparticles and the standardized protein purification protocols will make significant progress in "magic bullet" creation possible, bringing modern biomedicine to a new level. In this review, we are focused on the currently existing platforms for targeted self-assembling protein nanoparticles based on transferrin, lactoferrin, casein, lumazine synthase, albumin, ferritin, and encapsulin proteins, as well as on proteins from magnetosomes and virus-like particles. The applications of these self-assembling proteins for targeted delivery in vitro and in vivo are thoroughly discussed, including bioimaging applications and different therapeutic approaches, such as chemotherapy, gene delivery, and photodynamic and photothermal therapy. A critical assessment of these protein platforms' efficacy in biomedicine is provided and possible problems associated with their further development are described.

Peptides for diagnosis and treatment of ovarian cancer

Ovarian cancer is the most deadly gynecologic malignancy, and its incidence is gradually increasing. Despite improvements after treatment, the results are unsatisfactory and survival rates are relatively low. Therefore, early diagnosis and effective treatment remain two major challenges. Peptides have received significant attention in the search for new diagnostic and therapeutic approaches. Radiolabeled peptides specifically bind to cancer cell surface receptors for diagnostic purposes, while differential peptides in bodily fluids can also be used as new diagnostic markers. In terms of treatment, peptides can exert cytotoxic effects directly or act as ligands for targeted drug delivery. Peptide-based vaccines are an effective approach for tumor immunotherapy and have achieved clinical benefit. In addition, several advantages of peptides, such as specific targeting, low immunogenicity, ease of synthesis and high biosafety, make peptides attractive alternative tools for the diagnosis and treatment of cancer, particularly ovarian cancer. In this review, we focus on the recent research progress regarding peptides in the diagnosis and treatment of ovarian cancer, and their potential applications in the clinical setting.

GE11-antigen-loaded hepatitis B virus core antigen virus-like particles efficiently bind to TNBC tumor

Purpose

This study aimed to explore the possibility of utilizing hepatitis B core protein (HBc) virus-like particles (VLPs) encapsulate doxorubicin (Dox) to reduce the adverse effect caused by its off-target and toxic side effect.

Methods

Here, a triple-negative breast cancer (TNBC) tumor-targeting GE11-HBc VLP was constructed through genetic engineering. The GE11 peptide, a 12-amino-acid peptide targeting epidermal growth factor receptor (EGFR), was inserted into the surface protein loops of VLPs. The Dox was loaded into HBc VLPs by a thermal-triggered encapsulation strategy. The in vitro release, cytotoxicity, and cellular uptake of TNBC tumor-targeting GE11-HBc VLPs was then evaluated.

Results

These VLPs possessed excellent stability, DOX loading efficiency, and preferentially released drug payload at high GSH levels. The insertion of GE11 targeting peptide caused improved cellular uptake and enhanced cell viability inhibitory in EGFR high-expressed TNBC cells.

Conclusion

Together, these results highlight DOX-loaded, EGFR-targeted VLPs as a potentially useful therapeutic choice for EGFR-overexpressing TNBC.

Identification of a novel peptide ligand for the cancer-specific receptor mutation EGFRvIII using high-throughput sequencing of phage-selected peptides

We report here the selection and characterization of a novel peptide ligand using phage display targeted against the cancer-specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in several kinds of cancer: ovarian cancer, breast cancer and glioblastoma, but not in normal tissues. A 12-mer random peptide library was screened against EGFRvIII. Phage-selected peptides were sequenced in high-throughput by next generation sequencing (NGS), and their diversity was studied to identify highly abundant clones expected to bind with the highest affinities to EGFRvIII. The enriched peptides were characterized and their binding capacity towards stable cell lines expressing EGFRvIII, EGFR wild type (EGFR WT), or a low endogenous level of EGFR WT was confirmed by flow cytometry analysis. The best peptide candidate, VLGREEWSTSYW, was synthesized, and its binding specificity towards EGFRvIII was validated in vitro. Additionally, computational docking analysis suggested that the identified peptide binds selectively to EGFRvIII. The novel VLGREEWSTSYW peptide is thus a promising EGFRvIII-targeting agent for future applications in cancer diagnosis and therapy.

Chlorotoxin and Lung Cancer: A Targeting Perspective for Drug Delivery

In the generational evolution of nano-based drug delivery carriers, active targeting has been a major milestone for improved and selective drug accumulation in tissues and cell types beyond the existing passive targeting capabilities. Among the various active targeting moieties, chlorotoxin, a peptide extracted from scorpions, demonstrated promising tumor cell accumulation and selection. With lung cancer being among the leading diagnoses of cancer-related deaths in both men and women, novel therapeutic methodologies utilizing nanotechnology for drug delivery emerged. Given chlorotoxin's promising biological activity, we explore its potential against lung cancer and its utilization for active targeting against this cancer's tumor cells. Our analysis indicates that despite the extensive chlorotoxin's research against glioblastoma, lung cancer research with the molecule has been limited, despite some promising early results.

Quantum Dot-Based Screening Identifies F3 Peptide and Reveals Cell Surface Nucleolin as a Therapeutic Target for Rhabdomyosarcoma

Active drug delivery by tumor-targeting peptides is a promising approach to improve existing therapies for rhabdomyosarcoma (RMS), by increasing the therapeutic effect and decreasing the systemic toxicity, e.g., by drug-loaded peptide-targeted nanoparticles. Here, we tested 20 different tumor-targeting peptides for their ability to bind to two RMS cell lines, Rh30 and RD, using quantum dots Streptavidin and biotin-peptides conjugates as a model for nanoparticles. Four peptides revealed a very strong binding to RMS cells: NCAM-1-targeting NTP peptide, nucleolin-targeting F3 peptide, and two Furin-targeting peptides, TmR and shTmR. F3 peptide showed the strongest binding to all RMS cell lines tested, low binding to normal control myoblasts and fibroblasts, and efficient internalization into RMS cells demonstrated by the cytoplasmic delivery of the Saporin toxin. The expression of the nucleophosphoprotein nucleolin, the target of F3, on the surface of RMS cell lines was validated by competition with the natural ligand lactoferrin, by colocalization with the nucleolin-binding aptamer AS1411, and by the marked sensitivity of RMS cell lines to the growth inhibitory nucleolin-binding N6L pseudopeptide. Taken together, our results indicate that nucleolin-targeting by F3 peptide represents a potential therapeutic approach for RMS.