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1.
Future Oncol ; 19(2): 173-188, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36974606

ABSTRACT

Aim: To develop a cognitive dysfunction (CD) focused questionnaire to evaluate caregiver burden in glioblastoma. Materials & methods: The survey was developed from stakeholder consultations and a pilot study, and disseminated at eight US academic cancer centers. Caregivers self-reported caring for an adult with glioblastoma and CD. Results: The 89-item survey covered demographics, CD symptoms and caregiver burden domains. Among 185 caregivers, most were white, educated females and reported memory problems as the most common CD symptom. An exposure-effect was observed, with increase in number of CD symptoms significantly associated with greater caregiver burden. Conclusion: This questionnaire could guide caregiver interventions and be adapted for use longitudinally, in community cancer settings, and in patients with brain metastases.


Glioblastoma (GBM) is a very aggressive brain cancer. People who have GBM have trouble remembering things and are unable to do things they used to do. These changes can be very hard. Researchers are trying to better understand what it is like for people who take care of people with GBM (or caregivers). In this study, researchers created a new survey for caregivers. The survey included questions about what caregivers see happening in their loved one with GBM. Caregivers said that memory problems were common. Also, when the patient had more problems the caregiver had a harder time, too. Researchers hope to improve the survey and use it in the future for more studies.


Subject(s)
Cognitive Dysfunction , Glioblastoma , Adult , Female , Humans , Caregivers/psychology , Glioblastoma/complications , Glioblastoma/therapy , Glioblastoma/pathology , Pilot Projects , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/etiology , Cognitive Dysfunction/therapy , Surveys and Questionnaires , Quality of Life
2.
Support Care Cancer ; 30(2): 1365-1375, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34510238

ABSTRACT

BACKGROUND: Glioblastoma is an incurable disease with a poor prognosis. For caregivers of people with glioblastoma, the burden of care can be high. Patients often present with different clinical characteristics, which may impact caregiver burden in different ways. This study aimed to evaluate associations between patient clinical characteristics and caregiver burden/quality of life (QoL). METHODS: Caregiver-patient dyads were enrolled at 7 academic cancer centers in the United States. Eligible caregiver participants were self-reported as the primary caregiver of an adult living with glioblastoma and completed a caregiver burden survey. Eligible patients were age ≥ 18 years at glioblastoma diagnosis and alive when their respective caregiver entered the study, with the presence of cognitive dysfunction confirmed by the caregiver. Data were analyzed with descriptive statistics and multivariable analyses. RESULTS: The final cohort included 167 dyads. Poor patient performance status resulted in patient difficulty with mental tasks, more caregiving tasks, and increased caregiving time. Language problems were reported in patients with left-sided lesions. Patient confusion was negatively associated with all caregiver domains: emotional health, social health, general health, ability to work, confidence in finances, and overall QoL. Better caregiver QoL was observed in patients with frontal lobe lesions versus non-frontal lobe lesions. CONCLUSION: This study reinforced that patient performance status is a critical clinical factor that significantly affects caregiver burden, caregiving tasks, and caregiver time. Additionally, patient confusion affects multiple facets of caregiver burden/QoL. These results could be used to support guided intervention for caregiver support, customized to the patient experience.


Subject(s)
Glioblastoma , Quality of Life , Adolescent , Adult , Caregiver Burden , Caregivers , Cost of Illness , Glioblastoma/therapy , Humans , Surveys and Questionnaires
3.
Breast Cancer Res Treat ; 186(3): 839-850, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33389410

ABSTRACT

MAIN PURPOSE: Germline BRCA mutations (BRCAm) strongly influence the risk of developing breast cancer. This study aimed to understand the role of BRCAm testing in affected individuals and to assess its impact on the outcome of BRCAm carriers compared to non-carriers (BRCAwt) with breast cancer. RESEARCH QUESTION: The research question is "Does standard of care testing for BRCAm improve survival outcomes of breast cancer patients?" METHODS: In a single institution observational cohort study, demographic and clinical characteristics were compared between breast cancer patients with and without BRCAm. Frequency of BRCA testing was assessed. Survival outcomes were assessed by initial treatment setting stratified by BRCA status. RESULTS: Of 5712 identified women with breast cancer, 14.6% (n = 835) were tested for a BRCA mutation and had a documented result. The total number and proportion of women tested for a BRCAm increased between 2000 and 2014, resulting in an increased number of BRCAm carriers identified. However, the proportion of women who underwent testing and had a BRCAm decreased during the study period from 27.5% in 2000-2004 to 13.3% in 2010-2014. Disease-free survival was similar in the adjuvant and neoadjuvant treatment settings between BRCAm and BRCAwt patients. Progression-free survival on first line treatment and overall survival for patients with metastatic disease was also similar between BRCAm and BRCAwt patients. CONCLUSIONS: The proportion of women tested and the number of BRCAm identified increased during the study period despite a decreasing proportion of positive results among women tested.


Subject(s)
Breast Neoplasms , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Breast Neoplasms/epidemiology , Breast Neoplasms/genetics , Breast Neoplasms/therapy , Cohort Studies , Disease-Free Survival , Female , Germ-Line Mutation , Humans , Mutation
4.
BMC Health Serv Res ; 18(1): 165, 2018 03 07.
Article in English | MEDLINE | ID: mdl-29514700

ABSTRACT

BACKGROUND: Genetic counseling by a Genetic Counselor (GC) is a requirement prior to genetic testing for cancer susceptibility genes (GC-mandate policy) for some insurers. This study evaluated the impact of this policy from the patient perspective. METHODS: Surveys were sent to individuals for whom their insurer ordered genetic testing for the cancer susceptibility genes BCRA1 and BRCA2 over a 1 year time period that spanned the introduction of a GC-mandate policy. Responses were assessed by time period (before/after policy introduction) and genetic test completion. RESULTS: The surveys were completed by 1247/4950 (25.7%) eligible individuals. After policy introduction, there was no change in the proportion of respondents who completed genetic testing (p = 0.13) or had a mutation (p = 0.55). Overall decisional conflict (uncertainty or feeling uninformed) around genetic testing did not change after policy introduction (p = 0.16), but was significantly higher among respondents who did not complete genetic testing (p < 0.01). Although a larger proportion of respondents saw a GC after policy introduction (p < 0.01), fewer did so to better understand their test results (p < 0.01). The proportion of respondents who did not see a GC due to insurance issues/requirements and time restraints was higher among those tested after policy introduction or who did not complete genetic testing (p < 0.01). In multivariate analysis, respondents with a household income of $25,000 or greater were 3-times more likely to complete testing. CONCLUSIONS: A GC-mandate policy did not improve decisional conflict or increase the number of deleterious mutations identified and low-income respondents were less likely to complete testing. On the contrary, insurance requirements and time constraints may be preventing individuals at risk from receiving appropriate testing.


Subject(s)
Breast Neoplasms/genetics , Genetic Counseling , Genetic Testing , Insurance, Health/organization & administration , Organizational Policy , Adolescent , Adult , Conflict, Psychological , Decision Making , Female , Genes, BRCA1 , Genes, BRCA2 , Genetic Predisposition to Disease , Health Services Research , Humans , Middle Aged , Surveys and Questionnaires , Young Adult
6.
J Natl Compr Canc Netw ; 12(8): 1113-21, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25099443

ABSTRACT

Retrospective review of imatinib monitoring through electronic health records (EHR) can provide valuable insight into the current management of chronic myelogenous leukemia (CML). This study retrospectively reviewed EHRs from 2001 to 2010 of patients with chronic phase CML (CP-CML) treated with first-line imatinib. Chart evaluations included a review of cytogenetic and molecular testing, overall survival, adverse drug events (ADEs), and therapy modifications. A total of 54 patients with CP-CML were treated with first-line imatinib and had either cytogenetic or molecular testing within 18 months of imatinib initiation. Within the first 18 months of treatment, 33 of 45 patients (73%) undergoing cytogenetic testing experienced a complete cytogenetic response (median, 241 days; range, 110-542 days) and 24 of 48 patients (50%) receiving molecular testing achieved at least a major molecular response (median, 253 days; range, 99-546 days). The average number of cytogenetic and molecular tests conducted within the first 18 months was 2.5 and 3.8, respectively. Nineteen of 54 (35%) had a dose increase of imatinib (>400 mg; median, 329 days; range, 21-1968 days). The 5-year estimated overall survival rate was 88.5%. Between 2006 and 2010 (n=30; 56%), 7 patients (23%) transitioned to dasatinib or nilotinib (median, 399 days from diagnosis; range, 180-1046 days) because of suboptimal response or treatment failure (n=5) and imatinib ADEs (n=2). Forty-six imatinib-associated ADEs occurred in 31 patients (57%), of which 10 (32%) received dose reductions (median, 52 days) and 6 (19%) had discontinuations (median, 139 days). Closely monitored patients with CML treated with imatinib at an NCCN Member Institution experienced outcomes comparable to those reported in key clinical trials.


Subject(s)
Benzamides/administration & dosage , Drug-Related Side Effects and Adverse Reactions/epidemiology , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/epidemiology , Piperazines/administration & dosage , Pyrimidines/administration & dosage , Adult , Benzamides/adverse effects , Cytogenetic Analysis , Drug Resistance, Neoplasm/genetics , Drug-Related Side Effects and Adverse Reactions/pathology , Electronic Health Records , Female , Humans , Imatinib Mesylate , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Piperazines/adverse effects , Pyrimidines/adverse effects , Retrospective Studies , Survival Analysis
7.
Oncotarget ; 13: 257-270, 2022.
Article in English | MEDLINE | ID: mdl-35111281

ABSTRACT

BACKGROUND: Tumor mutational burden (TMB) is a potential biomarker to predict tumor response to immuno-oncology agents in patients with metastatic non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: A multi-site cohort study evaluated patients diagnosed with stage IV NSCLC between 2012 and 2019 who had received comprehensive genomic profiling (CGP) and any NSCLC-related treatment at 9 U.S. cancer centers. Baseline characteristics and clinical outcomes were compared between patients with TMB <10 and TMB ≥10. RESULTS: Among the 667 patients with CGP results, most patients received CGP from Foundation Medicine (64%) or Caris (20%). Patients with TMB ≥10 (vs. TMB <10) were associated with a positive smoking history. TMB was associated with ALK (p = 0.01), EGFR (p < 0.01), and TP53 (p < 0.05) alterations. TMB >10 showed a significant association towards longer overall survival (OS) (HR: 0.43, 95% CI: 0.21-0.88, p = 0.02) and progression-free survival (PFS) (HR: 0.43, 95% CI: 0.21-0.85, p = 0.02) in patients treated with first-line immunotherapy and tested by Foundation Medicine or Caris at treatment initiation. CONCLUSIONS: TMB levels greater than or equal to 10 mut/Mb, when tested by Foundation Medicine or Caris at treatment initiation, were significantly associated with improved OS and PFS among patients treated with first-line immunotherapy-containing regimens. Additional prospective research is warranted to validate this biomarker along with PD-L1 expression.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , B7-H1 Antigen/genetics , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/therapy , Cohort Studies , ErbB Receptors/genetics , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/therapy , Mutation , Prospective Studies , Receptor Protein-Tyrosine Kinases/genetics , Survival Analysis
8.
Mol Pharm ; 8(4): 1090-9, 2011 Aug 01.
Article in English | MEDLINE | ID: mdl-21599008

ABSTRACT

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer-docetaxel-RGDfK conjugate was synthesized, characterized, and evaluated in vitro and in vivo in comparison with untargeted low and high molecular weight HPMA copolymer-docetaxel conjugates. The targeted conjugate was designed to have a hydrodynamic diameter below renal threshold to allow elimination post treatment. All conjugates demonstrated the ability to inhibit the growth of DU145 and PC3 human prostate cancer cells and the HUVEC at low nanomolar concentrations. The targeted conjugate showed active binding to α(v)ß(3) integrins in both HUVEC and DU145 cells, whereas the untargeted conjugate demonstrated no evidence of specific binding. Efficacy at two concentrations (20 mg/kg and 40 mg/kg) was evaluated in nu/nu mice bearing DU145 tumor xenografts treated with a single dose of conjugates and compared with controls. RGDfK targeted and high molecular weight nontargeted conjugates exhibited the highest antitumor efficacy as evaluated by tumor regression. These results demonstrate that α(v)ß(3) integrin targeted polymeric conjugates with improved water solubility, reduced toxicity and ease of elimination post treatment in vivo are promising candidates for prostate cancer therapy.


Subject(s)
Acrylamides/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Polymers/chemistry , Prostatic Neoplasms/drug therapy , Taxoids/chemistry , Taxoids/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Docetaxel , Male , Mice , Mice, Nude , Taxoids/pharmacology
9.
Melanoma Res ; 29(6): 626-634, 2019 12.
Article in English | MEDLINE | ID: mdl-30688762

ABSTRACT

New melanoma therapies have shifted the expectations of patients and providers. Evaluating the impact of treatment characteristics may enhance shared decision making. A survey, including a discrete choice experiment, was utilized to evaluate perceived trade-offs of different melanoma treatments and to estimate out-of-pocket (OOP) willingness-to-pay (WTP) thresholds (January 2016 to March 2016). Participants included patients with melanoma at Huntsman Cancer Institute and their cancer care providers. Stakeholder focus groups were conducted to identify treatment attributes. Descriptive and comparative statistics and multinomial logit model were used to evaluate responses. Response rates were 41.9% (N = 220) for patients and 37.7% (N = 20) for providers. Immunotherapy and targeted therapy attributes considered important by participants were overall survival, immunotherapy-related side effects, and skin toxicities. Patients and providers had significantly different views of quality-of-life expectations, anxiety toward melanoma, trust to make treatment decisions, sharing concerns about treatment, time to discuss treatment, understanding OOP costs, and willingness to undergo/recommend treatment (half of the patients would undergo treatment if it was effective for > 24 months). Among patients, the average monthly OOP WTP for combination immunotherapy with nivolumab + ipilimumab was $ 2357 and for BRAF/MEK inhibitor was $1648. Among providers, these estimates were $ 2484 and $1350, respectively. Discordance existed between patients' and providers' perceptions about quality of life expectations, degree of anxiety, sharing of opinions, and progression-free survival. Our study suggests that patients and providers exhibit a higher OOP WTP for combination immunotherapy treatment compared with BRAF/MEK inhibitors, influenced predominately by overall survival expectations.


Subject(s)
Cancer Care Facilities/economics , Health Personnel/standards , Immunotherapy/methods , Melanoma/drug therapy , Melanoma/immunology , Patient Preference/statistics & numerical data , Skin Neoplasms/drug therapy , Skin Neoplasms/immunology , Aged , Female , Humans , Male , Middle Aged
11.
Article in English | MEDLINE | ID: mdl-25378949

ABSTRACT

CONTEXT: Determining human epidermal growth factor receptor 2 (HER2) status is critical for the management of early-stage breast cancer (ESBC). An understanding of HER2 testing practices can provide insight into how test results influence the use of HER2-directed therapy. OBJECTIVE: To assess HER2 testing, HER2+ disease, and HER2-directed therapy in ESBC at the Huntsman Cancer Institute before and after the 2007 American Society of Clinical Oncology and College of American Pathologist (ASCO/CAP) guidelines on HER2 testing were published. METHODS: Patients were identified from an institutional tumor registry. HER2 testing patterns and results were examined using a chart review of pathology and clinical notes. Patient characteristics, HER2+ rate, and trastuzumab use were evaluated descriptively. Discordance rate with reflex testing (immunohistochemistry [IHC]2+ retested by fluorescence in situ hybridization [FISH]) was also evaluated. RESULTS: A total of 1,459 women were included (mean age: 57 years). The rate of HER2+ disease was 17% (number [N] =245). The discordance rate between IHC2+ and FISH was 10%. After the 2007 ASCO/CAP guidelines, fewer tumors were classified as IHC3+ (16% post- versus 21.9% pre-2007), more tumors were characterized as IHC2+ (26.4% post- versus 20.7% pre-2007), and the overall HER2+ rate was decreased (18.7% versus 21.9%), but this was not statistically significant (P=0.519). Most patients with HER2+ ESBC received HER2-targeted therapy (N=185). CONCLUSION: The HER2+ rate was 17% and within the range of the reported rates in the literature. Reflex testing identified additional HER2+ tumors by approximately 10%, and should be considered a potential quality indicator. ASCO/CAP HER2 testing guidelines in 2007 appeared to impact the interpretation and classification of HER2+ tumors.

12.
Nanotoxicology ; 6(7): 713-23, 2012 Nov.
Article in English | MEDLINE | ID: mdl-21793770

ABSTRACT

The influence of size, surface charge and surface functionality of poly(amido amine) dendrimers and silica nanoparticles (SNPs) on their toxicity was studied in immunocompetent mice. After systematic characterization of nanoparticles, they were administered to CD-1 (caesarean derived-1) mice to evaluate acute toxicity. A distinct trend in nanotoxicity based on surface charge and functional group was observed with dendrimers regardless of their size. Amine-terminated dendrimers were fatal at doses >10 mg/kg causing haematological complications such as disseminated intravascular coagulation-like manifestations whereas carboxyl- and hydroxyl-terminated dendrimers of similar sizes were tolerated at 50-fold higher doses. In contrast, larger SNPs were less tolerated than smaller SNPs irrespective of their surface functionality. These findings have important implications in the use of these nanoparticles for various biomedical applications.


Subject(s)
Dendrimers/toxicity , Nanoparticles/chemistry , Nanoparticles/toxicity , Silicon Dioxide/toxicity , Amines/chemistry , Animals , Blood Proteins/metabolism , Dendrimers/chemistry , Disseminated Intravascular Coagulation/chemically induced , Female , Hemolysis/drug effects , Hemorrhage/chemically induced , Hemorrhage/pathology , Humans , Intestines/drug effects , Intestines/pathology , Liver/drug effects , Liver/pathology , Mice , Particle Size , Rats , Rats, Sprague-Dawley , Silicon Dioxide/chemistry , Surface Properties , Tissue Distribution
13.
Int J Pharm ; 420(1): 111-7, 2011 Nov 25.
Article in English | MEDLINE | ID: mdl-21856392

ABSTRACT

Polymeric micelles carrying the heat shock protein 90 inhibitor tanespimycin (17-N-allylamino-17-demethoxygeldanamycin) were synthesized using poly(styrene-co-maleic acid) (SMA) copolymers and evaluated in vitro and in vivo. SMA-tanespimycin micelles were prepared with a loading efficiency of 93%. The micelles incorporated 25.6% tanespimycin by weight, exhibited a mean diameter of 74 ± 7 nm by dynamic light scattering and a zeta potential of -35 ± 3 mV. Tanespimycin was released from the micelles in a controlled manner in vitro, with 62% released in 24h from a pH 7.4 buffer containing bovine serum albumin. The micellar drug delivery systems for tanespimycin showed potent activity against DU145 human prostate cancer cells, with an IC(50) of 230 nM. They further exhibited potent anti-cancer activity in vivo in nu/nu mice bearing subcutaneous DU145 human prostate cancer tumor xenografts, with significantly higher anticancer efficacy as measured by tumor regression when compared to free tanespimycin at an equivalent single dose of 10mg/kg. These data suggest further investigation of SMA-tanespimycin as a promising agent in the treatment of prostate cancer.


Subject(s)
Antineoplastic Agents/administration & dosage , Benzoquinones/administration & dosage , Drug Carriers , Lactams, Macrocyclic/administration & dosage , Maleates/chemical synthesis , Nanoparticles , Polystyrenes/chemical synthesis , Prostatic Neoplasms/drug therapy , Animals , Antineoplastic Agents/chemistry , Benzoquinones/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Chemistry, Pharmaceutical , Dose-Response Relationship, Drug , Drug Compounding , Humans , Hydrogen-Ion Concentration , Inhibitory Concentration 50 , Injections, Subcutaneous , Kinetics , Lactams, Macrocyclic/chemistry , Light , Male , Mice , Mice, Nude , Micelles , Nanotechnology , Prostatic Neoplasms/pathology , Scattering, Radiation , Solubility , Technology, Pharmaceutical/methods , Tumor Burden/drug effects , Xenograft Model Antitumor Assays
14.
J Control Release ; 151(3): 263-70, 2011 May 10.
Article in English | MEDLINE | ID: mdl-21223983

ABSTRACT

Tumor progression is dependent on neoangiogenesis for blood supply. Neovasculature over-express α(v)ß(3) integrins which recognize the Arg-Gly-Asp (RGD) sequence in the extracellular matrix. N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers containing side chains terminated in cyclic RGD analogs such as RGDfK show increased accumulation in prostate tumors. Geldanamycin and their derivatives (e.g., aminohexylgeldanamycin (AH-GDM)) are benzoquinone ansamycins that have both antiangiogenic and antitumor activity. In this work the antiangiogenic and antitumor activities of targetable HPMA copolymer-RGDfK-AH-GDM conjugates were compared with non-targetable systems in vitro and in vivo. Copolymer-drug conjugates containing RGDfK in the side chains showed superior activity against endothelial and prostate cancer cell lines in vitro, as well as higher inhibition of angiogenesis in vivo. At equimolar doses of the drug, the RGDfK containing conjugates showed significantly higher antitumor activity in nude mice bearing DU-145 human prostate cancer xenografts. These findings suggest the utility of HPMA copolymer-RGDfK conjugates for targeted delivery of geldanamycin analogs with a dual mode of action.


Subject(s)
Angiogenesis Inhibitors/therapeutic use , Benzoquinones/therapeutic use , Lactams, Macrocyclic/therapeutic use , Neovascularization, Pathologic/prevention & control , Peptides, Cyclic/therapeutic use , Polymethacrylic Acids/therapeutic use , Prostatic Neoplasms/blood supply , Prostatic Neoplasms/drug therapy , Angiogenesis Inhibitors/administration & dosage , Angiogenesis Inhibitors/chemical synthesis , Angiogenesis Inhibitors/chemistry , Animals , Benzoquinones/administration & dosage , Benzoquinones/chemical synthesis , Benzoquinones/chemistry , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Endothelial Cells/drug effects , Humans , Lactams, Macrocyclic/administration & dosage , Lactams, Macrocyclic/chemical synthesis , Lactams, Macrocyclic/chemistry , Male , Mice , Mice, Nude , Molecular Structure , Molecular Weight , Neovascularization, Pathologic/pathology , Peptides, Cyclic/administration & dosage , Peptides, Cyclic/chemical synthesis , Peptides, Cyclic/chemistry , Polymethacrylic Acids/administration & dosage , Polymethacrylic Acids/chemical synthesis , Polymethacrylic Acids/chemistry , Prostatic Neoplasms/pathology , Xenograft Model Antitumor Assays
15.
J Control Release ; 143(1): 71-9, 2010 Apr 02.
Article in English | MEDLINE | ID: mdl-20043962

ABSTRACT

Endocytic uptake and subcellular trafficking of a large array of HPMA (N-(2-hydroxypropyl)methacrylamide) based copolymers possessing positively or negatively charged residues, or hydrophobic groups were evaluated by flow cytometry and living cell confocal microscopy in cultured prostate cancer cells. The degrees of cellular uptake of various copolymer fractions with narrow polydispersities were quantified. The copolymer charge was the predominant physicochemical feature in terms of cellular uptake. Fast and efficient uptake occurred in positively charged copolymers due to non-specific adsorptive endocytosis, whereas slow uptake of negatively charged copolymers was observed. The uptake of copolymers was also molecular weight dependent. The copolymers were internalized into the cells through multiple endocytic pathways: positively charged copolymers robustly engaged clathrin-mediated endocytosis, macropinocytosis and dynamin-dependent endocytosis, while weakly negatively charged copolymers weakly employed these pathways; strongly negatively charged copolymers only mobilized macropinocytosis. HPMA copolymer possessing 4 mol% of moderately hydrophobic functional groups did not show preferential uptake. All copolymers ultimately localized in late endosomes/lysosomes via early endosomes; with varying kinetics among the copolymers. This study indicates that cell entry and subsequent intracellular trafficking of polymeric drug carriers are strongly dependent on the physicochemical characteristics of the nanocarrier, such as charge and molecular weight.


Subject(s)
Acrylamides/metabolism , Drug Carriers , Endocytosis , Prostatic Neoplasms/metabolism , Acrylamides/chemistry , Biological Transport , Cell Line, Tumor , Chemistry, Pharmaceutical , Chromatography, Gel , Clathrin/metabolism , Endosomes/metabolism , Flow Cytometry , Humans , Hydrophobic and Hydrophilic Interactions , Kinetics , Male , Microscopy, Confocal , Molecular Structure , Molecular Weight , Pinocytosis , Structure-Activity Relationship , Surface Properties , Technology, Pharmaceutical/methods , Transfection , rab GTP-Binding Proteins/genetics , rab GTP-Binding Proteins/metabolism
16.
Mol Pharm ; 6(3): 959-70, 2009.
Article in English | MEDLINE | ID: mdl-19344119

ABSTRACT

A new generation of antibodies against the prostate specific membrane antigen (PSMA) has been proven to bind specifically to PSMA molecules on the surface of living prostate cancer cells. To explore the potential of anti-PSMA antibodies as targeting moieties for macromolecular therapeutics for prostate cancer, fluorescently labeled HPMA (N-(2-hydroxypropyl)methacrylamide) copolymer-anti-PSMA antibody conjugates (P-anti-PSMA) were synthesized and the mechanisms of their endocytosis and subcellular trafficking in C4-2 prostate cancer cells were studied. Radioimmunoassays showed the dissociation constants of P-anti-PSMA for C4-2 prostate cancer cells in the low nanomolar range, close to values for free anti-PSMA. It indicated that conjugation of anti-PSMA to HPMA copolymers did not compromise their binding affinity. The rate of endocytosis of P-anti-PSMA was much faster than that of control HPMA copolymer conjugates containing nonspecific IgG. Selective pathway inhibitors of clathrin-mediated endocytosis and of macropinocytosis inhibited the internalization of P-anti-PSMA. Inhibition of clathrin-mediated endocytosis was further evidenced by down-regulation of clathrin heavy chain expression by siRNA. Using a dominant-negative mutant of dynamin (Dyn K44A) to abolish the clathrin-, caveolae-independent endocytic pathway, we found that some of P-anti-PSMA adopted this pathway to be endocytosed into C4-2 cells. Thus multiple receptor-mediated endocytic pathways, including clathrin-mediated endocytosis, macropinocytosis, and clathrin-, caveolae-independent endocytosis, were involved in the internalization of P-anti-PSMA. The extent of the participation of each pathway in P-anti-PSMA endocytosis was estimated. Membrane vesicles containing P-anti-PSMA rapidly colocalized with membrane vesicles overexpressing Rab7, a late endosome localized protein, demonstrating that a part of P-anti-PSMA was transported to late endosomes.


Subject(s)
Antibodies/chemistry , Methacrylates/chemistry , Polymers/chemistry , Polymers/metabolism , Prostate-Specific Antigen/immunology , Prostatic Neoplasms/metabolism , Transfection/methods , Antibodies/immunology , Antibodies/metabolism , Cell Line, Tumor , Clathrin/metabolism , Endocytosis/physiology , Flow Cytometry , Humans , Male , Molecular Structure , Polymers/chemical synthesis , Radioimmunoassay
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