A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective i...A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective in G1 DNA damage checkpoint.The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene.It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases.A 3Dstructure of Rb dimer is shown,confirming its multimeric status.Rb assumes a central role in cell cycle regulation and the“Rb pathway”is universally inactivated in human cancers.Hyperploidy refers to a state in which cells contain one or more extra chromosomes.Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells.The evidence for the triggering of hyperploid progression-mediated death in RBmutant human retinoblastoma cells is shown.Hence,the very genetic mutation that predisposes to cancer can be exploited to induce lethality.The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level.By triggering the lytic path,targeted therapy with tumor specificity at the genetic level can be developed.It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy.展开更多
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...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.展开更多
基金We are grateful to Tri Ngo for assistance with computer-based molecular modeling.Also acknowledged are the faculties at Johns Hopkins University,U.C.Berkeley,Baylor University,Davidson College(alma mater of United States president Woodrow Wilson,Nobel Prize 1919),Hollywood High School(alma mater of Hollywood classics actors,ex.Judy Garland in″The Wizard of Oz″),clinical staff(U.C.San Francisco),and actress in‘The Flying Nun’(Warner Bros.Pictures,Hollywood).City of Hope National Medical Center(National Comprehensive Cancer Network member)was established partly through the assistance of Hollywood's film industries(ex.Warner Bros.Pictures),supported by Hollywood’s renown figures(Frank Sinatra,Bob Hope,Ella Fitzgerald,etc.),visited by United States First Lady Eleanor(Franklin D.Roosevelt presidency),United States presidential candidate Robert F.Kennedy,Queen Elizabeth II(United Kingdom),graced by Pope John Paul II(Vatican,Italy),and supported by numerous distinguished individuals/industries.Its Beckman Research Institute was established by A.Beckman(California Institute of TechnologyBeckman Instruments).
文摘A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path“hyperploid progression-mediated death”targeting retinoblastoma(Rb)or p53-mutants defective in G1 DNA damage checkpoint.The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene.It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases.A 3Dstructure of Rb dimer is shown,confirming its multimeric status.Rb assumes a central role in cell cycle regulation and the“Rb pathway”is universally inactivated in human cancers.Hyperploidy refers to a state in which cells contain one or more extra chromosomes.Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells.The evidence for the triggering of hyperploid progression-mediated death in RBmutant human retinoblastoma cells is shown.Hence,the very genetic mutation that predisposes to cancer can be exploited to induce lethality.The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level.By triggering the lytic path,targeted therapy with tumor specificity at the genetic level can be developed.It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy.
文摘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.
