Research Progress on the Bone Metastasis Mechanism of Prostate Cancer and Bone-Targeted Drugs

Prostate cancer is a common male malignant tumor,and bone metastasis is one of the common complications in the late stage of prostate cancer.The mechanism of prostate cancer bone metastasis is a complex process involving multiple factors and steps.In recent years,with in-depth research on the mechanism of prostate cancer bone metastasis and the development of new drugs,important progress has been made in the treatment of prostate cancer bone metastasis.Based on this,this article introduces the mechanism of prostate cancer bone metastasis and the research progress of several bone-targeted drugs to provide reference and inspiration for future research.

Recent advances in promising drugs for primary prevention of gastroesophageal variceal bleeding with cirrhotic portal hypertension

Background:Gastroesophageal variceal bleeding is one of the most severe complications of patients with cirrhosis.Although primary prevention drugs,including non-selectiveβ-blockers,have effectively reduced the incidence of bleeding,their efficacy is limited due to side effects and related contraindications.With recent advances in precision medicine,precise drug treatment provides better treatment efficacy.Data sources:Literature search was conducted in PubMed,MEDLINE and Web of Science for relevant articles published up to May 2022.Information on clinical trials was obtained from https://clinicaltrials.gov/and http://www.chictr.org.cn/.Results:The in-depth understanding of the pathogenesis and advances of portal hypertension has enabled the discovery of multiple molecular targets for promising drugs.According to the site of action,these drugs could be classified into four classes:intrahepatic,extrahepatic,both intrahepatic and extrahepatic targets and others.All these classes of drugs offer advantages over traditional treatments in prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.Conclusions:This review classified and summarized the promising drugs,which prevent gastroesophageal variceal bleeding by targeting specific markers of pathogenesis of portal hypertension,demonstrating the significance of using the precision medicine strategy to discover and develop promising drugs for the primary prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.

Mitochondria targeting drugs for neurodegenerative diseases——Design, mechanism and application

Neurodegenerative diseases(NDDs) such as Alzheimer’s disease(AD) and Parkinson ’s disease(PD) are a heterogeneous group of disorders characterized by progressive degeneration of neurons.NDDs threaten the lives of millions of people worldwide and regretfully remain incurable.It is well accepted that dysfunction of mitochondria underlies the pathogenesis of NDDs.Dysfunction of mitochondria results in energy depletion,oxidative stress,calcium overloading,caspases activation,which dominates the neuronal death of NDDs.Therefore,mitochondria are the preferred target for intervention of NDDs.So far various mitochondria-targeting drugs have been developed and delightfully some of them demonstrate promising outcome,though there are still some obstacles such as targeting specificity,delivery capacity hindering the drugs development.In present review,we will elaborately address 1) the strategy to design mitochondria targeting drugs,2) the rescue mechanism of respective mitochondria targeting drugs,3) how to evaluate the therapeutic effect.Hopefully this review will provide comprehensive knowledge for understanding how to develop more effective drugs for the treatment of NDDs.

Anti-cancer drugs targeting using nanocarrier niosomes-a review

In the last few decades numbers of review and research articles have been published on niosomes. This shows the relevant interest of academias & researchers in niosomes because of the advantages sponsored by them over other colloidal drug delivery systems. Niosomes formation occurs when non-ionic surfactant vesicles assemble themselves. Various antineoplastic agents are used in chemotherapy, but they have some drawbacks that these agents cause cell death in normal tissues as well. There are two approaches to overcome this limitation. First, to modify the structure of existing drugs, but this will not possible because it changes the properties of drugs. Second, the development of nano-carriers like liposomes, dendrimers, nanoparticles, niosomes et al. Among all, niosomes (non-ionic surfactant vesicles) have more advantages besides all nano-carriers. Drugs either hydrophilic in nature or hydrophobic in nature, both can be incorporated in niosomes. And by embedding specific ligands over vesicular surface enables us to target the drug to specific cancer cells.

Glucocorticoids-based prodrug design:Current strategies and research progress

Attributing to their broad pharmacological effects encompassing anti-inflammation,antitoxin,and immunosuppression,glucocorticoids(GCs)are extensively utilized in the clinic for the treatment of diverse diseases such as lupus erythematosus,nephritis,arthritis,ulcerative colitis,asthma,keratitis,macular edema,and leukemia.However,longterm use often causes undesirable side effects,including metabolic disorders-induced Cushing's syndrome(buffalo back,full moon face,hyperglycemia,etc.),osteoporosis,aggravated infection,psychosis,glaucoma,and cataract.These notorious side effects seriously compromise patients'quality of life,especially in patients with chronic diseases.Therefore,glucocorticoid-based advanced drug delivery systems for reducing adverse effects have received extensive attention.Among them,prodrugs have the advantages of low investment,low risk,and high success rate,making them a promising strategy.In this review,we propose the strategies for the design and summarize current research progress of glucocorticoid-based prodrugs in recent decades,including polymer-based prodrugs,dendrimer-based prodrugs,antibody-drug conjugates,peptide-drug conjugates,carbohydrate-based prodrugs,aliphatic acid-based prodrugs and so on.Besides,we also raise issues that need to be focused on during the development of glucocorticoid-based prodrugs.This review is expected to be helpful for the research and development of novel GCs and prodrugs.

A proteomic landscape of pharmacologic perturbations for functional relevance

Pharmacological perturbation studies based on protein-level signatures are fundamental for drug discovery. In the present study, we used a mass spectrometry (MS)-based proteomic platform to profile the whole proteome of the breast cancer MCF7 cell line under stress induced by 78 bioactive compounds. The integrated analysis of perturbed signal abundance revealed the connectivity between phenotypic behaviors and molecular features in cancer cells. Our data showed functional relevance in exploring the novel pharmacological activity of phenolic xanthohumol, as well as the noncanonical targets of clinically approved tamoxifen, lovastatin, and their derivatives. Furthermore, the rational design of synergistic inhibition using a combination of histone methyltransferase and topoisomerase was identified based on their complementary drug fingerprints. This study provides rich resources for the proteomic landscape of drug responses for precision therapeutic medicine.

Mutations in Ras homolog family member A in patients with peripheral T-cell lymphoma and implications for personalized medicine

Genome sequencing has revealed frequent mutations in Ras homolog family member A(RHOA)among various cancers with unique aberrant profiles and pathogenic effects,especially in peripheral T-cell lymphoma(PTCL).The discrete positional distribution and types of RHOA amino acid substitutions vary according to the tumor type,thereby leading to different functional and biological properties,which provide new insight into the molecular pathogenesis and potential targeted therapies for various tumors.However,the similarities and discrepancies in characteristics of RHOA mutations among various histologic subtypes of PTCL have not been fully elucidated.Herein we highlight the inconsistencies and complexities of the type and location of RHOA mutations and demonstrate the contribution of RHOA variants to the pathogenesis of PTCL by combining epigenetic abnormalities and activating multiple downstream pathways.The promising potential of targeting RHOA as a therapeutic modality is also outlined.This review provides new insight in the field of personalized medicine to improve the clinical outcomes for patients.

Risk Factors of Depression Screened by Two-Sample Mendelian Randomization Analysis:A Systematic Review

Objective This study explored the potentially modifiable factors for depression and major depressive disorder(MDD)from the MR-Base database and further evaluated the associations between drug targets with MDD.Methods We analyzed two-sample of Mendelian randomization(2SMR)using genetic variant depression(n=113,154)and MDD(n=208,811)from Genome-Wide Association Studies(GWAS).Separate calculations were performed with modifiable risk factors from MR-Base for 1,001 genomes.The MR analysis was performed by screening drug targets with MDD in the DrugBank database to explore the therapeutic targets for MDD.Inverse variance weighted(IVW),fixed-effect inverse variance weighted(FE-IVW),MR-Egger,weighted median,and weighted mode were used for complementary calculation.Results The potential causal relationship between modifiable risk factors and depression contained 459 results for depression and 424 for MDD.Also,the associations between drug targets and MDD showed that SLC6A4,GRIN2A,GRIN2C,SCN10A,and IL1B expression are associated with an increased risk of depression.In contrast,ADRB1,CHRNA3,HTR3A,GSTP1,and GABRG2 genes are candidate protective factors against depression.Conclusion This study identified the risk factors causally associated with depression and MDD,and estimated 10 drug targets with significant impact on MDD,providing essential information for formulating strategies to prevent and treat depression.

Comprehensive analysis of the role of ubiquitin-specific peptidases in colorectal cancer:A systematic review

BACKGROUND Colorectal cancer(CRC)is the third most frequent and the second most fatal cancer.The search for more effective drugs to treat this disease is ongoing.A better understanding of the mechanisms of CRC development and progression may reveal new therapeutic strategies.Ubiquitin-specific peptidases(USPs),the largest group of the deubiquitinase protein family,have long been implicated in various cancers.There have been numerous studies on the role of USPs in CRC;however,a comprehensive view of this role is lacking.AIM To provide a systematic review of the studies investigating the roles and functions of USPs in CRC.METHODS We systematically queried the MEDLINE(via PubMed),Scopus,and Web of Science databases.RESULTS Our study highlights the pivotal role of various USPs in several processes implicated in CRC:Regulation of the cell cycle,apoptosis,cancer stemness,epithelial–mesenchymal transition,metastasis,DNA repair,and drug resistance.The findings of this study suggest that USPs have great potential as drug targets and noninvasive biomarkers in CRC.The dysregulation of USPs in CRC contributes to drug resistance through multiple mechanisms.CONCLUSION Targeting specific USPs involved in drug resistance pathways could provide a novel therapeutic strategy for overcoming resistance to current treatment regimens in CRC.

Integrated causal inference modeling uncovers novel causal factors and potential therapeutic targets of Qingjin Yiqi granules for chronic fatigue syndrome

Objective:Chronic fatigue syndrome(CFS)is a prevalent symptom of post-coronavirus disease 2019(COVID-19)and is associated with unclear disease mechanisms.The herbal medicine Qingjin Yiqi granules(QJYQ)constitute a clinically approved formula for treating post-COVID-19;however,its potential as a drug target for treating CFS remains largely unknown.This study aimed to identify novel causal factors for CFS and elucidate the potential targets and pharmacological mechanisms of action of QJYQ in treating CFS.Methods:This prospective cohort analysis included 4,212 adults aged≥65 years who were followed up for 7 years with 435 incident CFS cases.Causal modeling and multivariate logistic regression analysis were performed to identify the potential causal determinants of CFS.A proteome-wide,two-sample Mendelian randomization(MR)analysis was employed to explore the proteins associated with the identified causal factors of CFS,which may serve as potential drug targets.Furthermore,we performed a virtual screening analysis to assess the binding affinity between the bioactive compounds in QJYQ and CFS-associated proteins.Results:Among 4,212 participants(47.5%men)with a median age of 69 years(interquartile range:69–70 years)enrolled in 2004,435 developed CFS by 2011.Causal graph analysis with multivariate logistic regression identified frequent cough(odds ratio:1.74,95%confidence interval[CI]:1.15–2.63)and insomnia(odds ratio:2.59,95%CI:1.77–3.79)as novel causal factors of CFS.Proteome-wide MR analysis revealed that the upregulation of endothelial cell-selective adhesion molecule(ESAM)was causally linked to both chronic cough(odds ratio:1.019,95%CI:1.012–1.026,P=2.75 e^(−05))and insomnia(odds ratio:1.015,95%CI:1.008–1.022,P=4.40 e^(−08))in CFS.The major bioactive compounds of QJYQ,ginsenoside Rb2(docking score:−6.03)and RG4(docking score:−6.15),bound to ESAM with high affinity based on virtual screening.Conclusions:Our integrated analytical framework combining epidemiological,genetic,and in silico data provides a novel strategy for elucidating complex disease mechanisms,such as CFS,and informing models of action of traditional Chinese medicines,such as QJYQ.Further validation in animal models is warranted to confirm the potential pharmacological effects of QJYQ on ESAM and as a treatment for CFS.

Targeting Effect Study of ￣(3) H-Mitoxantrone Nanosphereson Hepatocellular Carcinoma(HCC) Model in Nude Mice

The distribution of ￣(3)H-mitoxantrone polybutyl cyanoacrylate nanospheres(￣(3)H-DHAQ-PBCA-NS)in the viscera,muscle and tumors of human hepatocellular carcinoma (HCC)model in nude mice was studied with liquid scintillation counting techniique. The results showed that the ￣(3)H-DHAQ-PBCA-NS had remarkable liver targeting effect. The content of ￣(3)H-DHAQ-PBCA-NSin liver and heterotopic liver tumor was found to be 71.31±10. 49% of total amount of drug in animal body. It was also found that the content of ￣(3)H-DHAQ-PBCA-NS in liver was higher than that in liver tissue, and the content of ￣(3)H-DHAQ-PBCA-NS in annpit tumor was higher than that in armpit muscle tissue,but had no significant difference;It provides an ideal preparation for the DHAQ admini-stration.

In silico antiplasmodial effects of phytocompounds derived from Andrographis paniculata on validated drug targets of different stages of Plasmodium falciparum

Background:Andrographis paniculata has been widely reported as an herbal plant for malaria treatment.The increasing rate of resistance to recommended antimalarial drugs has justified the need for a continuous search for new and more potent drugs that target all stages of the Plasmodium falciparum life cycle from natural plant sources.This study aimed to determine the antiplasmodial effect of phytocompounds derived from A.paniculata on the stages of plasmodium falciparum.Methods:Phytocompounds from A.paniculata were identified by Gas Chromatography-Mass Spectrophotometry(GCMS)analysis.The phytocompounds were screened for their druggability using Lipinski’s rule of five and subjected to Absorption,Distribution,Metabolism,Excretion,Toxicity(ADMET)and druglikeness analysis.The phytocompounds were docked against some validated drug targets at different stages of Plasmodium falciparum(hepatic,asexual,sexual,and vector targets)using PyRx software to analyze the inhibitory potential and protein-ligand interaction.Thereafter,the stability and flexibility of the best complexes were assessed through molecular dynamics simulations at 50ns using WebGRO.Result:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl exhibited a higher binding affinity and better stability throughout the simulation period with P.falciparum dihydrofolate reductase-thymidylate synthase and Plasmodium falciparum M1 alanyl aminopeptidase for asexual blood stage and gametocyte stage of Plasmodium falciparum,respectively than the existing drugs.Meanwhile,N-Ethyl-3-methoxy-4-methylphenethylamine was also found to have a higher binding affinity and more stability throughout the simulation period with P.falciparum purine nucleoside phosphorylase and Plasmodium falciparum gametocyte surface protein for Hepatic schizonts stage of Plasmodium falciparum and gametocyte transmission blocking stage,respectively,than the existing drugs.Conclusion:The 7a-Isopropenyl-4,5-dimethyloctahydroinden-4-yl and N-Ethyl-3-methoxy-4 methylphenethylamine from A.paniculata are predicted as an antimalarial drug candidate.Thus,it is recommended that in vitro and in vivo bioassays be conducted on these hit compounds to validate these predictions.

A Study on the Multi-Compartment Linear Circulation Pharmacokinetic Model for the Targeting Drug Delivery System

By analyzing the observed phenomena and the data collected in the study, a multi-compartment linear circulation model for targeting drug delivery system was developed and the function formulas of the drug concentration-time in blood and target organ by computing were figured out. The drug concentration-time curve for target organ can be plotted with reference to the data of drug concentration in blood according to the model. The pharmacokinetic parameters of the drug in target organ could also be obtained. The practicability of the model was further checked by the curves of drug concentration-time in blood and target organ(liver) of liver-targeting nanoparticles in animal tests. Based on the liver drug concentration-time curves calculated by the function formula of the drug in target organ, the pharmacokinetic behavior of the drug in target organ(liver) was analyzed by statistical moment, and its pharmacokinetic parameters in liver were obtained. It is suggested that the (relative targeting index( can be used for quantitative evaluation of the targeting drug delivery systems.

Brain delivering RNA-based therapeutic strategies by targeting mTOR pathway for axon regeneration after central nervous system injury

Injuries to the central nervous system(CNS)such as stroke,brain,and spinal cord trauma often result in permanent disabilities because adult CNS neurons only exhibit limited axon regeneration.The brain has a surprising intrinsic capability of recovering itself after injury.However,the hostile extrinsic microenvironment significantly hinders axon regeneration.Recent advances have indicated that the inactivation of intrinsic regenerative pathways plays a pivotal role in the failure of most adult CNS neuronal regeneration.Particularly,substantial evidence has convincingly demonstrated that the mechanistic target of rapamycin(mTOR)signaling is one of the most crucial intrinsic regenerative pathways that drive axonal regeneration and sprouting in various CNS injuries.In this review,we will discuss the recent findings and highlight the critical roles of mTOR pathway in axon regeneration in different types of CNS injury.Importantly,we will demonstrate that the reactivation of this regenerative pathway can be achieved by blocking the key mTOR signaling components such as phosphatase and tensin homolog(PTEN).Given that multiple mTOR signaling components are endogenous inhibitory factors of this pathway,we will discuss the promising potential of RNA-based therapeutics which are particularly suitable for this purpose,and the fact that they have attracted substantial attention recently after the success of coronavirus disease 2019 vaccination.To specifically tackle the blood-brain barrier issue,we will review the current technology to deliver these RNA therapeutics into the brain with a focus on nanoparticle technology.We will propose the clinical application of these RNA-mediated therapies in combination with the brain-targeted drug delivery approach against mTOR signaling components as an effective and feasible therapeutic strategy aiming to enhance axonal regeneration for functional recovery after CNS injury.

Novel therapeutic approaches targeting L-type amino acid transporters for cancer treatment

L-type amino acid transporters(LATs) mainly assist the uptake of neutral amino acids into cells. Four LATs(LAT1, LAT2, LAT3 and LAT4) have so far been identified. LAT1(SLC7A5) has been attracting much attention in the field of cancer research since it is commonly up-regulated in various cancers. Basic research has made it increasingly clear that LAT1 plays a predominant role in malignancy. The functional significance of LAT1 in cancer and the potential therapeutic application of the features of LAT1 to cancer management are described in this review.

Self-assembled Nanoparticles based on Folic Acid Modifi ed Carboxymethyl Chitosan Conjugated with Targeting Antibody

Nanoparticles conjugated with antibody were designed as active drug delivery system to reduce the toxicity and side effects of drugs for acute myeloid leukemia（AML）.Moreover,methotrexate（MTX）was chosen as modeldrug and encapsulate within folic acid modified carboxymethylchitosan（FACMCS）nanoparticles through self-assembling.The chemicalstructure,morphology,release and targeting of nanoparticles were characterized by routine detection.It is demonstrated that the mean diameter is about 150 nm,the release rate increases with the decreasing of p H,the binding rate of CD33 antibody and FA-CMCS nanoparticles is about 5：2,and nanoparticles can effectively bind onto HL60 cells in vitro.The experimentalresults indicate that the FA-CMCS nanoparticles conjugated with antibody may be used as a potentialp Hsensitive drug delivery system with leukemic targeting properties.

Process Modeling of Ferrofluids Flow for Magnetic Targeting Drug Delivery

Among the proposed techniques for delivering drugs to specific sites within the human body, magnetic targeting drug delivery surpasses due to its non-invasive character and its high targeting efficiency. Although there have been some analyses theoretically for magnetic drug targeting, very few researchers have addressed the hydrodynamic models of magnetic fluids in the blood vessel of human body. This paper presents a mathematical model to describe the hydrodynamics of ferrofluids as drug carriers flowing in a blood vessel under the applied magnetic field. A 3D flow field of magnetic particles in a blood vessel model is numerically simulated in order to further understand clinical application of magnetic targeting drug delivery. Simulation results show that magnetic nanoparticles can be enriched in a target region depending on the applied magnetic field intensity. Magnetic resonance imaging confirms the enrichment of ferrofluids in a desired body tissue of Sprague-Dawley rats. The simulation results coincide with those animal experiments. Results of the analysis provide the important information and can suggest strategies for improving delivery in favor of the clinical application.

Hydrodynamic modeling of ferrofluid flow in magnetic targeting drug delivery

Among the proposed techniques for delivering drugs to specific locations within human body, magnetic drug targeting prevails due to its non-invasive character and its high targeting efficiency. Magnetic targeting drug delivery is a method of carrying drug-loaded magnetic nanoparticles to a target tissue target under the applied magnetic field. This method increases the drug concentration in the target while reducing the adverse side-effects. Although there have been some theoretical analyses for magnetic drug targeting, very few researchers have addressed the hydrodynamic models of magnetic fluids in the blood vessel. A mathematical model is presented to describe the hydrodynamics of ferrofiuids as drug carriers flowing in a blood vessel under the applied magnetic field. In this model, magnetic force and asymmetrical force are added, and an angular momentum equation of magnetic nanoparticles in the applied magnetic field is modeled. Engineering approximations are achieved by retaining the physically most significant items in the model due to the mathematical complexity of the motion equations. Numerical simulations are performed to obtain better insight into the theoretical model with computational fluid dynamics. Simulation results demonstrate the important parameters leading to adequate drug delivery to the target site depending on the magnetic field intensity, which coincident with those of animal experiments. Results of the analysis provide important information and suggest strategies for improving delivery in clinical application.

Effective combinations of anti-cancer and targeted drugs for pancreatic cancer treatment

Pancreatic cancer is highly aggressive and lethal.Due to the lack of effective methods for detecting the disease at an early stage,pancreatic cancer is frequently diagnosed late.Gemcitabine has been the standard chemotherapy drug for patients with pancreatic cancer for over 20 years,but its anti-tumor effect is limited.Therefore,FOLFIRINOX(leucovorin,fluorouracil,irinotecan,oxaliplatin)as well as combination therapies using gemcitabine and conventional agents,such as cisplatin and capecitabine,has also been administered;however,these have not resulted in complete remission.Therefore,there is a need to develop novel and effective therapies for pancreatic cancer.Recently,some studies have reported that combinations of gemcitabine and targeted drugs have had significant antitumor effects on pancreatic cancer cells.As gemcitabine induced DNA damage response,the proteins related to DNA damage response can be suitable additional targets for novel gemcitabine-based combination therapy.Furthermore,KRAS/RAF/MEK/ERK signaling triggered by oncogenic mutated KRAS and autophagy are frequently activated in pancreatic cancer.Therefore,these characteristics of pancreatic cancer are potential targets for developing effective novel therapies.In this minireview,combinations of gemcitabine and targeted drugs to these characteristics,combinations of targeted drugs,combinations of natural products and anti-cancer agents,including gemcitabine,and combinations among natural products are discussed.

Tumor specifically internalizing peptide ‘HN-1’: Targeting the putative receptor retinoblastoma-regulated discoidin domain receptor 1 involved in metastasis

BACKGROUND Less than 0.5%of intravenously injected drugs reach tumors,contributing to side effects.To limit damage to healthy cells,various delivery vectors have been formulated;yet,previously developed vectors suffer from poor penetration into solid tumors.This issue was resolved by the discovery of HN-1 peptide isolated via biopanning a phage-display library.HN-1 targets human head and neck squamous cell carcinoma(HNSCC)(breast,thyroid;potentially lung,cervix,uterine,colon cancer),translocates across the cell membrane,and efficiently infiltrates solid tumors.HN-1 peptide has been conjugated to various anticancer drugs and imaging agents though the identity of its receptor remained enigmatic.AIM To decipher the clues that pointed to retinoblastoma(Rb)-regulated discoidindomain receptor 1 as the putative receptor for HN-1 is described.METHODS HN-1 peptide was synthesized and purified using reverse-phase highperformance liquid chromatography and gel electrophoresis.The predicted mass was confirmed by mass spectroscopy.To image the 3-dimensional structure of HN-1 peptide,PyMOL was used.Molecular modeling was also performed with PEP-FOLD3 software via RPBS bioinformatics web portal(INSERM,France).The immunohistochemistry results of discoidin domain receptor 1(DDR1)protein were obtained from the publicly accessible database in the Human Protein Atlas portal,which contained the images of immunohistochemically labeled human cancers and the corresponding normal tissues.RESULTS The clues that led to DDR1 involved in metastasis as the putative receptor mediating HN-1 endocytosis are the following:(1)HN-1 is internalized in phosphate-buffered saline and its uptake is competitively inhibited;(2)HN-1(TSPLNIHNGQKL)exhibits similarity with a stretch of amino acids in alpha5 beta3 integrin(KLLITIHDRKEF).Aside from two identical residues(Ile-His)in the middle,the overall distribution of polar and nonpolar residues throughout the sequences is nearly identical.As HN-1 sequence lacks the Arg-Gly-Asp motif recognized by integrins,HN-1 may interact with an"integrin-like"molecule.The tertiary structure of both peptides showed similarity at the 3-dimensional level;(3)HN-1 is internalized by attached cells but not by suspended cells.As culture plates are typically coated with collagen,collagen-binding receptor(expressed by adherent but not suspended cells)may represent the receptor for HN-1;(4)DDR1 is highly expressed in head and neck cancer(or breast cancer)targeted by HN-1;(5)Upon activation by collagen,DDR1 becomes internalized and compartmentalized in endosomes consistent with the determination of’energy-dependent clathrin-mediated endocytosis’as the HN-1 entry route and the identification of HN-1 entrapped vesicles as endosomes;and(6)DDR1 is essential for the development of mammary glands consistent with the common embryonic lineage rationale used to identify breast cancer as an additional target of HN-1.In summary,collagenactivated tyrosine kinase receptor DDR1 overexpressed in HNSCC assumes a critical role in metastasis.Further studies are warranted to assess HN-1 peptide’s interaction with DDR1 and the therapeutic potential of treating metastatic cancer.Additionally,advances in delivery(conformation,endocytic mechanism,repertoire of targeted cancers of HN-1 peptide),tracking(HN-1 conjugated imaging agents),and activity(HN-1 conjugated therapeutic agents)are described.CONCLUSION The discovery of DDR1 as HN-1 peptide’s putative receptor represents a significant advance as it enables identification of metastatic cancers or clinical application of previously developed therapeutics to block metastasis.