Optophoresis Accurately Predicts Response to Chemotherapy in CLL.

Abstract In vitro drug resistance assays have shown efficacy in predicting response to chemotherapeutic drugs in a number of solid tumors. In chronic lymphocytic leukemia (CLL) many assays are limited by the difficulty involved in culturing these cells ex vivo. We have developed a novel, optical-based methodology that is sensitive to broad cellular physical characteristics, such as morphology, size, refractive index, density and surface properties. This measurement, known as Optophoresis, quantifies cell motion induced by exposure to a moving optical gradient, generated from a near-infrared laser beam (Forster AH, et al. Anal Biochem 2004, 327(1):14–22 and Wang MM, et al. Appl Opt 2003, 42(28):5765–73). In Optophoresis small numbers of cells are analyzed intact, in their native state. No labels are required for quantification of functional responses, but cell subpopulations may be identified using fluorescent tags. We have used this assay to predict response to chemotherapeutic agents in patients with CLL. Methods: We performed Optophoresis with six drugs (fludarabine, chlorambucil, vincristine, cyclophosphamide, cladribine and prednisolone) on 74 CLL patient samples. 68 of these were classic B-CLL; there was one hairy cell variant, two were T-CLL, two evolved to PLL and one evolved to lymphoma. 21 of the samples were from patients for whom clinical data on response to chemotherapy was available for 33 drug treatments. Response to therapy was defined as a decrease in RAI stage. Results: 21 patients aged 58 to 93 years; 71% Rai stage III or IV were included in this analysis. Six patients were evaluated prospectively, with the assay performed before chemotherapy administration, and 15 patients were evaluated retrospectively with the assay performed after a course of treatment. Optophoresis accurately predicted response to chemotherapy in 88% of the 33 treatments evaluated. In the four instances for which the Optophoresis results did not match the retrospective clinical outcome; the patient was historically sensitive to treatment and Optophoresis results indicated current resistance to the drug. Subsequent resistance to drug therapy is known to occur in a significant percentage of treated CLL patients. Conclusion: Optophoresis of CLL cells accurately predicts response to chemotherapy in CLL. Further studies using results of Optophoresis to guide CLL treatment are warranted.

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Molecular imaging and deep learning analysis of uMUC1 expression in response to chemotherapy in an orthotopic model of ovarian cancer

Scientific Reports ◽

10.1038/s41598-020-71890-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hongwei Zhao ◽

Hasaan Hayat ◽

Xiaohong Ma ◽

Daguang Fan ◽

Ping Wang ◽

...

Keyword(s):

Neural Networks ◽

Ovarian Cancer ◽

Deep Learning ◽

Cancer Progression ◽

In Vivo Imaging ◽

Near Infrared ◽

Response To Therapy ◽

Response To Chemotherapy

Abstract Artificial Intelligence (AI) algorithms including deep learning have recently demonstrated remarkable progress in image-recognition tasks. Here, we utilized AI for monitoring the expression of underglycosylated mucin 1 (uMUC1) tumor antigen, a biomarker for ovarian cancer progression and response to therapy, using contrast-enhanced in vivo imaging. This was done using a dual-modal (magnetic resonance and near infrared optical imaging) uMUC1-specific probe (termed MN-EPPT) consisted of iron-oxide magnetic nanoparticles (MN) conjugated to a uMUC1-specific peptide (EPPT) and labeled with a near-infrared fluorescent dye, Cy5.5. In vitro studies performed in uMUC1-expressing human ovarian cancer cell line SKOV3/Luc and control uMUC1low ES-2 cells showed preferential uptake on the probe by the high expressor (n = 3, p < .05). A decrease in MN-EPPT uptake by SKOV3/Luc cells in vitro due to uMUC1 downregulation after docetaxel therapy was paralleled by in vivo imaging studies that showed a reduction in probe accumulation in the docetaxel treated group (n = 5, p < .05). The imaging data were analyzed using deep learning-enabled segmentation and quantification of the tumor region of interest (ROI) from raw input MRI sequences by applying AI algorithms including a blend of Convolutional Neural Networks (CNN) and Fully Connected Neural Networks. We believe that the algorithms used in this study have the potential to improve studying and monitoring cancer progression, amongst other diseases.

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Efficient Photoacoustic Imaging With Biomimetic Mesoporous Silica-Based Nanoparticles

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.762956 ◽

2021 ◽

Vol 9 ◽

Author(s):

Chuangjia Huang ◽

Xiaoling Guan ◽

Hui Lin ◽

Lu Liang ◽

Yingling Miao ◽

...

Keyword(s):

Mesoporous Silica ◽

Near Infrared ◽

Ex Vivo ◽

Photoacoustic Imaging ◽

Mesoporous Silica Nanoparticles ◽

Good Biocompatibility ◽

Targeting Ability ◽

Body Clearance

Indocyanine green (ICG), a near-infrared (NIR) fluorescent dye approved by the Food and Drug Administration (FDA), has been extensively used as a photoacoustic (PA) probe for PA imaging. However, its practical application is limited by poor photostability in water, rapid body clearance, and non-specificity. Herein, we fabricated a novel biomimetic nanoprobe by coating ICG-loaded mesoporous silica nanoparticles with the cancer cell membrane (namely, CMI) for PA imaging. This probe exhibited good dispersion, large loading efficiency, good biocompatibility, and homologous targeting ability to Hela cells in vitro. Furthermore, the in vivo and ex vivo PA imaging on Hela tumor-bearing nude mice demonstrated that CMI could accumulate in tumor tissue and display a superior PA imaging efficacy compared with free ICG. All these results demonstrated that CMI might be a promising contrast agent for PA imaging of cervical carcinoma.

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A Novel Multiparameter Flow Cytometric Cytotoxicity Assay Detects p53 Deletion as the Major Cause of In Vitro Resistance to Fludarabine in B-Cell Chronic Lymphocytic Leukemia.

Blood ◽

10.1182/blood.v106.11.4470.4470 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4470-4470

Author(s):

James Z. Huang ◽

Antony C. Bakke ◽

Guang Fan ◽

Rita Braziel ◽

Ken M. Gatter ◽

...

Keyword(s):

Drug Sensitivity ◽

Drug Exposure ◽

Leukemic Cell ◽

Chemotherapeutic Agents ◽

Lymphocytic Leukemia ◽

Leukemic Cells ◽

Multiparameter Flow Cytometry ◽

Diagnostic Strategy ◽

Significant Difference

Abstract Individual patients with B-CLL demonstrate variable responses to standard induction and salvage therapeutic regimens. It would be highly desirable to develop a predictable and reproducible laboratory diagnostic strategy that guides the selection of appropriate drugs and/or regimens based on the drug sensitivity and resistance profiles of leukemic cells for individual patients. As a first step towards this goal, a study was designed to investigate the differences of in vitro drug sensitivity profiles of leukemic cells with different cytogenetic abnormalities from CLL patients. CLL cells from 43 patients were incubated in vitro with four commonly used chemotherapeutic agents (fludarabine, chlorambucil, cladribine or prednisolone) individually or in combination. Multiparameter flow cytometry was utilized to determine the decrease in leukemic cell viability after drug exposure. Both fresh and cryopreserved samples were assessed and were found to be equivalent for assay, regardless of the percentage of B-CLL cells or the degree of spontaneous apoptosis. The highest in vitro resistance to fludarabine, was seen in all seven cases of B-CLL cells with deletions of p53, a cytogenetic abnormality associated with poor clinical outcome. Interestingly, in vitro response to chlorambucil and prednisolone was seen some CLL cases with p53 deletion and correlated with clinical response to these drugs. In CLL cases without p53 deletion, a marked variability in vitro drug sensitivity CLL cells was observed but no significant difference was detected among cases with normal cytogenetics (n=13), ATM deletion (n=4), trisomy 12 (n=3), or 13q deletion (n=7). Our findings provide direct evidence of cellular resistance to fludarabine in CLL associated with p53 deletion, confirming prior clinical observations. In vitro drug sensitivity assay may prove useful in guiding choices for therapy for CLL patients based on the drug sensitivity profile of leukemic cells in individuals.

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Identification of Three Tyrosine Phosphorylation Sites in the p53 Binding Domain of Apoptosis-Stimulating p53 Protein 2 (ASPP2) That Are Differentially Phosphorylated in Response to Chemotherapy in Patient Derived AML Blasts

Blood ◽

10.1182/blood.v118.21.1396.1396 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1396-1396

Author(s):

Kerstin M Kampa-Schittenhelm ◽

Charles D Lopez ◽

Marcus M Schittenhelm

Keyword(s):

Acute Leukemia ◽

Tyrosine Phosphorylation ◽

Ex Vivo ◽

Phosphorylation Sites ◽

Apoptosis Induction ◽

P53 Mutations ◽

Expression Levels ◽

C Terminus ◽

Response To Chemotherapy

Abstract Abstract 1396 Acute myeloid leukemias (AML) are difficult to treat, and risk-stratification for successful chemotherapy remains a major challenge. Inactivation of the p53 tumor suppressor pathway is a frequent event in many cancers that promotes tumorigenesis and resistance to chemotherapy. However, p53 mutations are rare in AML, and thus the p53-pathway must be inactivated by other mechanisms. ASPP2 is a haploinsufficient tumor suppressor that belongs to a family of p53-binding proteins that enhance apoptosis in part by stimulation of p53-transactivation of selected pro-apoptotic target genes. High ASPP2 expression levels in the absence of p53 mutations thereby argue for proper apoptosis induction capacity and thereby for better response rates. Indeed, low ASPP2 expression levels are correlated with aggressive courses of different tumors. As we have previously shown by qPCR (Kampa-Schittenhelm et al., ASH 2010) and confirm now by intracellular immunostaining in a larger patient cohort, ASPP2 expression levels vary widely in acute leukemias. In vitro silencing of ASPP2 transcription leads to abrogation of induction of apoptosis after application of chemotherapy, arguing for inferior in vivo response rates to therapy of patients lacking ASPP2 expression. Of note, the highest expression levels we have seen was in a patient with good prognosis core binding factor leukemia lacking an autoactivating KIT mutation. The p53 core domain must interact with the ASPP2 C-terminus to fully stimulate apoptotic function. To further investigate how regulation of the p53-ASPP2 interaction may play a role in apoptosis induction in AML, we identified several highly conserved and highly predicted tyrosine phosphorylation sites at the ASPP2 C-terminus. To study whether these sites modulate the p53-ASPP2 interaction and apoptotic function, we developed phospho-specific antibodies against the three highest-scoring phosphorylation sites and confirmed. tyrosine phosphorylation at Y1029, Y1046 and Y1114 in ex vivo blasts from AML patients. Intriguingly, based on the crystal structure of the p53-ASPP2 complex, phosphorylation of all three tyrosines is predicted to disrupt p53-ASPP2 binding. Tantalizingly, we found that these phosphorylation expression patterns changed after in vitro treatment of native blasts with chemotherapy: blasts treated with daunorubicin revealed an early change of tyrosine phosphorylation patterns. Using these new phospho-specific antibodies, we are continuing to analyze changes in phosphorylation patterns in primary AML blasts (with and without ex vivo chemotherapy) and are performing univariate and multivariate analysis to correlate with available clinical data. Preliminary data suggests that altered ASPP2 tyrosine phosphorylation in AML may play an important role in modulating response to chemotherapy-induced apoptosis in the absence of inactivating p53 mutations. Ongoing work is prospectively analyzing pY-ASPP2 in patients with acute leukemia during induction chemotherapy. These results aim to evaluate ASPP2 expression as an early-on prediction marker of therapy response in acute leukemia. Further, we aim to provide new and clinically relevant insight into p53 pathway inactivation in acute leukemia – which suggests a novel potential target for therapy to increase the effectiveness of chemotherapy in these patients. Disclosures: No relevant conflicts of interest to declare.

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Trace FVIII Augments Rfviia Induced Thrombin Generation and Improves Hemostasis in Hemophilia A Patients with Inhibitors: A clinical Cohort Study

Blood ◽

10.1182/blood.v120.21.40.40 ◽

2012 ◽

Vol 120 (21) ◽

pp. 40-40

Author(s):

Tami Livnat ◽

Uri Martinowitz ◽

Shirley Azar-Avivi ◽

Ariela Zivelin ◽

Gili Kenet

Keyword(s):

Thrombin Generation ◽

Hemophilia A ◽

Conflicts Of Interest ◽

Ex Vivo ◽

Therapy Response ◽

Response To Therapy ◽

Individual Therapy ◽

Severe Bleeding ◽

Inhibitor Level

Abstract Abstract 40 Treatment of Hemophilia A patients with inhibitors is challenging, as correlation between inhibitor level and hemostatic response to therapy may be limited. Thrombin generation (TG) assays may be used to monitor hemostasis and/or predict patients' response to various bypass agents. Since combination of excess FVIII and bypassing agents may potentiate improved TG in inhibitor plasma tested in-vitro, we aimed to define the therapeutic feasibility of co-administration of rFVIIa and FVIII in hemophilia A patients with inhibitors. Patients and Methods: Following consent, blood was sampled from 15 hemophilia patients (age: 0.5–46y) with inhibitor (0.5–668 BU). Platelet poor plasma (PPP) was prepared, spiked and incubated with excess FVIII. Ex-vivo kinetics of FVIII neutralization over time was evaluated by sequential measurements of residual FVIII activity. We then used recalcification induced-TG (performed in PPP supplemented with 4μM phospholipids), to measure the ex-vivo response to increasing concentrations of FVIII (0–200%) and rFVIIa (0–6.8μg/ml), alone or in combination. Based upon these ex-vivo studies, an individually tailored therapeutic regimen of concomitant bolus doses of rFVIIa and FVIII was applied to nine hemophilia patients with inhibitors. Results: FVIII ex- vivo measurements post incubation detected either rapid or slow neutralization- not correlating with inhibitor level. Flat baseline TG curves were recorded for all inhibitor patients, with variable responses to FVIII and/or rFVIIa. Combined spiking with FVIII and rFVIIa dramatically increased rFVIIa induced ETP (762.7 ±305.7 as compared to 339.3±179.9 nM/min with rFVIIa only) and peak height (48.7±23.6 vs 23.7±16.6) in all patients' plasma samples. Based upon individual ex vivo assays, concomitant bolus doses of rFVIIa (120–200 mcg/kg) and FVIII (50–100 U/Kg), were applied to 9 patients, for a total of 333 episodes during study period (February 2010-Septemeber 2012). Patients during immune tolerance received rFVIIa prophylaxis with combined rFVIIa/FVIII dosing applied 3 times weekly. For most mild- moderate joint bleeds hemostasis was defined as satisfactory following a single combined dose. Severe bleeding episodes or target joint bleeds responded to 2–8 (median:3) combined doses, applied every 12 hours. During study period the median number of spontaneous joint bleeds decreased from 4 to 1 per month. Neither thrombosis nor any other complications evolved. Conclusions: Prediction of individual therapy response may be achieved by pre-analytical studies, assessing FVIII neutralization kinetics as well as ex-vivo TG responses to combined bypass/FVIII therapy. Such studies enabled treatment of inhibitor patients according to individually tailored regimens. We confirmed for the first time that the in- vitro advantage of combining FVIII and rFVIIa, indeed accounts for improved hemostasis and may safely be applied to inhibitor patients. Disclosures: No relevant conflicts of interest to declare.

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SF3B1 Mutations in CLL Are Equivalent to p53/ATM Dysfunction and Cause Defective Puma Upregulation in Response to Chemotherapy

Blood ◽

10.1182/blood.v120.21.711.711 ◽

2012 ◽

Vol 120 (21) ◽

pp. 711-711 ◽

Cited By ~ 2

Author(s):

Doreen te Raa ◽

Ingrid AM Derks ◽

Dieuwertje M Luijks ◽

Jacoline van Laar ◽

Hanneke Monsuur ◽

...

Keyword(s):

Poor Prognosis ◽

Target Genes ◽

Conflicts Of Interest ◽

Lymphocytic Leukemia ◽

Splicing Factor ◽

Clinical Prognosis ◽

Mrna Induction ◽

Response To Chemotherapy ◽

Recurrent Mutations

Abstract Abstract 711 Mutations or deletions of the tumor suppressor p53 or its upstream kinase ATM are well-known determinants of poor prognosis in Chronic Lymphocytic Leukemia (CLL). In recent years, genome wide sequencing has uncovered novel gene mutations that correspond with poor prognosis. Specifically, recurrent mutations in the splicing factor SF3B1 and the Notch and NRAS/KRAS oncogenes have been found. These mutations were (in part) mutually exclusive with p53 and/or ATM mutations, which suggested overlap in biological function. Here, we report results of a comparative analysis of p53 target genes and in vitro drug responses in CLL samples with either p53 (n=9), ATM (n=10), SF3B1 (n=11), Notch (n=6), or NRAS/KRAS (n=4) gene deletions/mutations. We found that upon irradiation, mRNA induction of all tested p53 targets genes (p21, Puma, CD95, Bax, PCNA, FXDR) was clearly decreased in all SF3B1 mutated CLL samples (overall p<0.001). SF3B1 samples resembled ATM mutated/11q− CLL in displaying a defective but not absent p53 response. In contrast, Notch and KRAS/NRAS mutations did not affect RNA induction of apoptosis inducers Puma and Bax. At the protein level, Puma and p21 induction were defective or absent in SF3B1 mutated CLL. This corresponded with decreased apoptosis after in vitro treatment with fludarabine. Treatment with nutlin, either alone or in combination with fludarabine, restored cell death induction, again indicating an overlap with ATM dysfunction. To establish possible causality between SF3B1 mutation and ATM dysfunction, more genetic and functional studies are ongoing and will be reported. In conclusion, the recently described mutations in a splicing factor in CLL can be linked at the functional level to defective ATM and/or p53 target gene responses, providing an explanation for the poor clinical prognosis of CLL patients with SF3B1 mutations. Disclosures: No relevant conflicts of interest to declare.

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Development of a Human Therapeutic L-Cyst(e)Ine-Degrading Enzyme for the Treatment of Hematological Malignancies

Blood ◽

10.1182/blood.v128.22.1587.1587 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1587-1587

Author(s):

Giulia Agnello ◽

Susan Alters ◽

Joseph Tyler ◽

Jinyun Liu ◽

Peng Huang ◽

...

Keyword(s):

Research Funding ◽

Hematological Malignancies ◽

Ex Vivo ◽

Redox Balance ◽

Lymphocytic Leukemia ◽

Employment Equity ◽

Equity Ownership ◽

Antioxidant Mechanisms

Abstract Cancer cells experience higher intrinsic oxidative stress than their normal counterparts and acquire adaptive antioxidant mechanisms to maintain redox balance. This increased antioxidant capacity has been correlated to malignant transformation, metastasis and resistance to standard anticancer drugs. This enhanced antioxidant state also correlates with cancer cells being more vulnerable to additional oxidative insults, therefore disruption of adaptive antioxidant mechanisms may have significant therapeutic implications. Hematological malignancies including Chronic Lymphocytic Leukemia (CLL), Acute Lymphocytic Leukemia (ALL), Acute Myeloid Leukemia (AML) and Multiple Myeloma (MM) are critically dependent on the cellular antioxidant glutathione (GSH), consistent with the higher intrinsic oxidative stress. L-cysteine is the rate-limiting substrate for GSH biosynthesis and adequate levels of cysteine are critical to maintain the intracellular homeostasis of GSH. CLL and a subset of ALL cells have been reported to rely on the stromal supply of cysteine to increase the synthesis of GSH in order to maintain redox balance, which in turn promotes cell survival and fosters drug resistance. One approach to target this cancer specific dependency is by therapeutic depletion of amino acids via enzyme administration; a clinically validated strategy for the treatment of ALL. Aeglea BioTherapeutics Inc. has developed a bioengineered cysteine and cystine degrading enzyme (Cyst(e)inase, AEB3103) and evaluated its therapeutic efficacy against hematological malignancies in in vitro, ex vivo and in vivo pre-clinical studies. The TCL1-TG:p53 -/- mouse model exhibits a drug resistant phenotype resembling human CLL with unfavorable cytogenetic alterations and highly aggressive disease progression. AEB3103 greatly decreased the viability of TCL1-TG:p53 -/- cells cultured in vitro, whereas the CLL therapeutic, fludarabine, showed minimal cytotoxic effects. In vivo treatment of TCL1-TG:p53 -/- mice with AEB3103 resulted in an increase in median survival time (7 months, p<0.0001) compared to the untreated control group (3.5 months, p<0.001) and a fludarabine treated group (5.3 months, p<0.001). These results indicate a superior therapeutic effect of AEB3103 compared to fludarabine. Additionally, evaluation of AEB3103 in in vitro 2D cultures of patient-derived CLL and MM cells, and in ex vivo 3D cultures of cells derived from ALL and AML PDx models resulted in significant cell growth inhibition with therapeutically relevant IC50 values. Collectively these results demonstrate the sensitivity of hematological malignancies to modulation of GSH levels via AEB3103-mediated cyst(e)ine depletion. Disclosures Agnello: Aeglea BioTherapeutics: Employment. Alters:Aeglea BioTherapeutics: Employment, Equity Ownership. Tyler:Aeglea BioTherapeutics: Employment, Equity Ownership. Huang:Aeglea BioTherapeutics: Research Funding. Stone:Aeglea Biotherapeutics: Consultancy, Equity Ownership, Research Funding; University of Texas at Austin: Employment, Patents & Royalties: I am an inventor of technology related to this abstract. Georgiou:Aeglea Biotherapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Lowe:Aeglea BioTherapeutics: Employment, Equity Ownership. Rowlinson:Aeglea BioTherapeutics: Employment, Equity Ownership.

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c-Abl kinase inhibitors overcome CD40-mediated drug resistance in CLL: implications for therapeutic targeting of chemoresistant niches

Blood ◽

10.1182/blood-2008-03-146704 ◽

2008 ◽

Vol 112 (13) ◽

pp. 5141-5149 ◽

Cited By ~ 75

Author(s):

Delfine Y. H. Hallaert ◽

Annelieke Jaspers ◽

Carel J. van Noesel ◽

Marinus H. J. van Oers ◽

Arnon P. Kater ◽

...

Keyword(s):

Drug Resistance ◽

Kinase Inhibitors ◽

Ex Vivo ◽

Lymphocytic Leukemia ◽

Erk Activation ◽

Abl Kinase ◽

Cd40 Stimulation ◽

Sublethal Doses ◽

Erk Inhibition

Abstract In lymph node (LN) proliferation centers in chronic lymphocytic leukemia (CLL), the environment protects from apoptotic and cytotoxic triggers. Here, we aimed to define the molecular basis for the increased drug resistance and searched for novel strategies to circumvent it. The situation in CLL LN could be mimicked by prolonged in vitro CD40 stimulation, which resulted in up-regulation of antiapoptotic Bcl-xL, A1/Bfl-1, and Mcl-1 proteins, and afforded resistance to various classes of drugs (fludarabine, bortezomib, roscovitine). CD40 stimulation also caused ERK-dependent reduction of Bim-EL protein, but ERK inhibition did not prevent drug resistance. Drugs combined with sublethal doses of the BH3-mimetic ABT-737 displayed partial and variable effects per individual CD40-stimulated CLL. The antiapoptotic profile of CD40-triggered CLL resembled BCR-Abl–dependent changes seen in chronic myeloid leukemia (CML), which prompted application of c-Abl inhibitors imatinib or dasatinib. Both compounds, but especially dasatinib, prevented the entire antiapoptotic CD40 program in CLL cells, and restored drug sensitivity. These effects also occurred in CLL samples with dysfunctional p53. Importantly, ex vivo CLL LN samples also displayed strong ERK activation together with high Bcl-xL and Mcl-1 but low Bim levels. These data indicate that CLL cells in chemoresistant niches may be sensitive to therapeutic strategies that include c-Abl inhibitors.

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Mutant p53 Gain of Function and Chemoresistance: The Role of Mutant p53 in Response to Clinical Chemotherapy

Chemotherapy ◽

10.1159/000446361 ◽

2016 ◽

Vol 62 (1) ◽

pp. 43-53 ◽

Cited By ~ 35

Author(s):

Chao He ◽

Lun Li ◽

Xuan Guan ◽

Li Xiong ◽

Xiongying Miao

Keyword(s):

B Cell Lymphoma ◽

Chemotherapeutic Agents ◽

Lymphocytic Leukemia ◽

Chemotherapy Response ◽

Mutant P53 ◽

Gain Of Function ◽

Pubmed Database ◽

Response To Chemotherapy ◽

The Impact

Purpose: To review mechanisms underlying mutant p53 (mutp53) gain of function (GOF) and mutp53-induced chemoresistance, and to investigate the role of mutp53 in response to clinical chemotherapy. Methods: We searched the PubMed database for clinical studies from the past decade, including data evaluating the impact of mutp53 in clinical chemotherapy response. Results: Interactions between mutp53 and transcriptional factors, proteins or DNA structures, as well as epigenetic regulation, contribute to mutp53 GOF. Major mechanisms of mutp53-induced chemoresistance include enhanced drug efflux and metabolism, promoting survival, inhibiting apoptosis, upregulating DNA repair, suppressing autophagy, elevating microenvironmental resistance and inducing a stem-like phenotype. Clinically, mutp53 predicted resistance to chemotherapy in diffuse large B-cell lymphoma, and esophageal and oropharyngeal cancers, but its impact on chronic lymphocytic leukemia was unclear. In bladder cancer, mutp53 did not predict resistance, whereas in some breast and ovarian cancers, it was associated with sensitivity to certain chemotherapeutic agents. Conclusion: mutp53 has an intricate role in the response to clinical chemotherapy and should not be interpreted in isolation. Furthermore, when predicting tumor response to chemotherapy based on the p53 status, the drugs used should also be taken into consideration. These concepts require further investigation.

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IN VIVO NEAR-INFRARED FLUORESCENCE IMAGING OF HUMAN COLON ADENOCARCINOMA BY SPECIFIC IMMUNOTARGETING OF A TUMOR-ASSOCIATED MUCIN

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545809000759 ◽

2009 ◽

Vol 02 (04) ◽

pp. 407-422 ◽

Cited By ~ 3

Author(s):

RALPH S. DACOSTA ◽

YING TANG ◽

TUULA KALLIOMAKI ◽

RAYMOND M. REILLY ◽

ROBERT WEERSINK ◽

...

Keyword(s):

Fluorescence Microscopy ◽

Fluorescence Imaging ◽

Normal Tissue ◽

Near Infrared ◽

Ex Vivo ◽

Colon Adenocarcinoma ◽

Human Colon ◽

Human Colon Adenocarcinoma

Background and Aims: Accurate endoscopic detection of premalignant lesions and early cancers in the colon is essential for cure, since prognosis is closely related to lesion size and stage. Although it has great clinical potential, autofluorescence endoscopy has limited tumor-to-normal tissue image contrast for detecting small preneoplastic lesions. We have developed a molecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate which targets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescence-based endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T) subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivo whole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology. Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours post injection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstrated that modification of CC49 antibodies did not alter their specific tumor-localizing properties, and was antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probe targeting a tumor-associated mucin detects colonic tumors at the molecular level in real time, and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.

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