CB-839, panitumumab, and irinotecan in RAS wildtype (WT) metastatic colorectal cancer (mCRC): Phase I results.

2019 ◽  
Vol 37 (4_suppl) ◽  
pp. 574-574 ◽  
Author(s):  
Kristen Keon Ciombor ◽  
Jennifer Whisenant ◽  
Dana Backlund Cardin ◽  
Laura Williams Goff ◽  
Satya Das ◽  
...  
Keyword(s):  
Cell Growth ◽  
Phase I ◽  
Phase Ii ◽  
Critical Role ◽  
Mitogen Activated Protein Kinase ◽  
Hematologic Toxicity ◽  
Elevated Alkaline Phosphatase ◽  
Egfr Inhibition ◽  
Elevated Liver Enzymes

574 Background: Epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) are approved in RAS WT mCRC; however, patients (pts) will develop resistance to these agents. Alterations in glutamine (Gln) metabolism play a critical role in cancer cell growth. In cancers such as CRC, EGFR and Gln cooperate to provide signals and fuel for mitogen activated protein kinase-dependent cell growth. Our in vitro data show that Gln abrogates EGFR inhibition, and blockade of Gln transport restores sensitivity. We also observed a greater antitumor response in vivo with EGFR mAb plus CB-839, an inhibitor of a rate-limiting enzyme of Gln metabolism, than either agent alone. We designed a phase I/II study (NCT03263429) to evaluate CB-839 + panitumumab + irinotecan in anti-EGFR refractory RAS WT mCRC. Methods: Dose escalation used a Bayesian continual reassessment method targeting a 25% toxicity probability. CB-839 (600 mg or 800 mg twice daily [BID]) were evaluated with panitumumab (6 mg/kg) and irinotecan (180 mg/m2). Irinotecan was included in phase I to establish a future phase II dose of the triplet. Prior EGFR mAb treatment (tx) was not required for phase I. Dose-limiting toxicity (DLT) was any tx-related non-hematologic ≥Gr 3 toxicity (except fatigue, rash, or elevated liver enzymes) or ≥Gr 4 hematologic toxicity during the first 28 days. Results: Nine pts have been enrolled; 2 were not evaluable for DLT and replaced. Zero DLTs were observed at dose level 1 (n = 3) or 2 (n = 4); 2 more pts are needed to confirm the maximum tolerated dose (MTD). Most frequent toxicities were anemia and hypomagnesemia (88%) and elevated alkaline phosphatase, nausea, and rash (75%), most ≤Gr 2. One of 7 evaluable pts (14%) has an ongoing partial response, and 5 pts had stable disease (SD; 71%). Three pts have been on tx > 6 months, and 3 pts with prior EGFR mAb tx achieved SD. Conclusions: Triplet combination was tolerable at full doses of each drug, and preliminary antitumor activity was observed in a majority of pts. Phase II will begin after phase I completion and will evaluate efficacy of CB-839 (800 mg BID) and panitumumab (6 mg/kg). Imaging studies using investigational PET tracers to evaluate Gln metabolism as a function of tumor response are planned. Clinical trial information: NCT03263429.

Dual epidermal growth factor receptor (EGFR) inhibition: Phase I study combining cetuximab (C225) and erlotinib (E) in advanced solid tumors

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 3552-3552
Author(s):  
R. Sangha ◽  
C. Ho ◽  
L. Beckett ◽  
D. H. Lau ◽  
P. N. Lara ◽  
...  
Keyword(s):  
Phase I ◽  
Solid Tumors ◽  
Dose Level ◽  
Phase Ii ◽  
Dose Escalation ◽  
Gene Copy ◽  
Hematologic Toxicity ◽  
Advanced Solid Tumors ◽  
Egfr Inhibition ◽  
Biomarker Analysis

3552 Background: The EGFR pathway is implicated in lung tumorigenesis by aberrantly regulating cell proliferation, apoptosis, and invasion. Maximal blockade of the EGFR can be achieved by dually inhibiting the extracellular and intracellular domain with the monoclonal antibody C225 and the tyrosine kinase inhibitor, E. Given preclinical synergy of C225 and E, we hypothesized this combination would be feasible and result in improved therapeutic benefit. Methods: Patients (pts) with advanced solid tumors were enrolled using a standard phase I dose escalation design. C225 was administered IV weekly, with no loading dose, and E given orally daily on a 28-day cycle. Four dose levels were studied: C225 150 mg/m2, E 100 mg; C225 200 mg/m2, E 100 mg; C225 250 mg/m2, E 100 mg; and C225 250 mg/m2, E 150 mg. Dose limiting toxicity (DLT) was defined as: grade (Gr) 4 platelets, Gr 3 platelets with bleeding, febrile neutropenia, ≥ Gr 3 ANC with documented infection, or clinically significant > Gr 3 non-hematologic toxicity. Gr 3 rash based solely on pain or Gr 3 hypersensitivity infusion reactions were not considered DLTs. Results: 18 pts were treated: 13 NSCLC, 3 H&N, 1 pancreas, and 1 invasive thymoma. Characteristics: Age range 41–80, median 62.5; Gender: 7 M; ECOG PS ≤1 = 17; Prior chemo ≤1 = 10. Planned dose escalation was completed without reaching the MTD. The highest dose level was expanded to 6 pts. A single DLT for Gr 3 diarrhea was observed at the second dose level (C225 200 mg/m2, E 100 mg). Gr 3/4 toxicities were: lymphopenia (3), acneiform rash (3), nausea/vomiting (3), pruritis (1), fatigue (1), diarrhea (1), confusion (1), hypomagnesemia (1), hypocalcemia (1), hyponatremia (1), hyperkalemia (1), and anemia (1). Of 13 evaluable pts, 1 PR (NSCLC) and 4 with SD (2 NSCLC, 2 H&N). Median cycles: 2 (1–14) with one NSCLC pt on therapy for 8 cycles and one H&N pt receiving 14 cycles. Biomarker analysis of EGFR polymorphisms, gene copy number via FISH, and protein expression will be presented, along with the mutation status of EGFR and KRAS. Conclusions: 1) Dual EGFR inhibition with C225 250 mg/m2 weekly and E 150 mg daily is feasible, well tolerated, and the recommended phase II dose. 2) Efficacy of this combination in NSCLC is being evaluated in a phase II trial. [Table: see text]

Phase I/II Results of a Multicenter Trial of Perifosine (KRX-0401) + Bortezomib in Patients with Relapsed or Relapsed/Refractory Multiple Myeloma Who Were Previously Relapsed from or Refractory to Bortezomib

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 870-870 ◽  
Author(s):  
Paul Richardson ◽  
Jeffrey Wolf ◽  
Andrzej Jakubowiak ◽  
Jeffrey Zonder ◽  
Sagar Lonial ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Phase I ◽  
Phase Ii ◽  
Phase 1 ◽  
Multicenter Trial ◽  
Toxicity Assessment ◽  
Clinical Activity ◽  
Hematologic Toxicity ◽  
Refractory Multiple Myeloma

Abstract INTRODUCTION: Perifosine (Peri) is an orally -bioavailable, novel signal transduction modulator with multiple pathway effects including inhibition of Akt and activation of JNK. Peri first demonstrated activity in combination with dexamethasone (dex) in patients (pts) with advanced, relapsed/refractory multiple myeloma (MM) (ASH 2007 #1164). Of interest were experiments conducted combining Peri with bortezomib (Velcade®, Vel). In vitro, Peri + Vel shows at least additive cytotoxicity against MM cells with Peri inhibiting Vel induced Akt activation (Hideshima et. al, BLOOD 2006). We conducted a phase I/II study with encouraging safety and clinical activity of the combination seen in the phase I portion of the trial, including a 56% ORR (ASH 2007 # 1170). Herein, we report on the combined phase I/II results (n=76) which determined the safety and activity of Peri + Vel 322 PATTerNS of CAre 2008 ASH ANNUAl MeeTiNG ABSTrACTS, VolUMe 112, iSSUe 11, NoVeMBer 16, 2008 (+/− dex), in pts with relapsed and relapsed/refractory MM, who were previously relapsed from or refractory to Vel. METHODS: The phase I stage of the study enrolled a total of 18 pts in 4 cohorts (≥3 pts each) with dosing of Peri 50 mg or 100 mg (daily) and Vel 1.0 or 1.3 mg/m2 (d 1, 4, 8, 11) in 21-d cycles. The selected dose for phase II was Peri 50 mg qd + Vel 1.3 mg/m2 (d 1, 4, 8, 11) in 21-d cycles, with a planned enrollment of 64 pts. Dex 20mg (on day of and after each Vel dose) could be added in pts with progressive disease (PD). NCI CTCAE v3.0 was used for toxicity assessment. For the phase I portion, DLT was defined as any grade (G) 3 non-hematologic toxicity, G4 neutropenia for 5 d and/or neutropenic fever, or platelets <10,000/mm3 on >1 occasion despite transfusion. Response was assessed by modified EBMT and Uniform criteria. RESULTS: A total of 76 pts have been enrolled (18 pts in phase I and 58 in phase II) comprised of 45 men and 31 women, median age 63 y, (range 41 – 89). 84% of pts had relapsed/refractory MM, with a median of 6 lines of prior treatment (range 2–13). Prior therapy included Vel (100%), dex (95%), thalidomide (79%), lenalidomide (71%) and SCT (57%). 63 pts have completed at least one cycle and were evaluable for safety (13 pts are currently not evaluable; 3 were removed in cycle 1 and 10 are too early in their treatment). Most common (□ 10%) grade 1/2 events were nausea, diarrhea, fatigue and myelosuppression, which were manageable with supportive care and growth factors. Grade 3/4 adverse events 5% included thrombocytopenia (40%); lymphopenia (36%); neutropenia (21%); anemia (14%); hyponatremia (13%); leukopenia (11%); proteinuria (8%), and upper respiratory infection (6%). No DVT has been seen, and only 1 worsening peripheral neuropathy from grade 1 to 3 has been reported to date: 2 pts had Peri reduced to 50 mg (nausea, fatigue) in the phase 1 cohort, and 7 pts had Vel dose reductions primarily due to hematologic toxicity. 57 pts have completed at least 2 cycles and are evaluable for response, with best response to Peri + Vel (+/− dex) as follows: CR PR MR ORR SD All Patients:Best Response N=57 2 4% 7 12% 14 25% 23 40% 23 40% Peri + Vel 57 1 2% 5 9% 8 14% 14 24% 17 30% With dex added* 31 1 2% 2 3% 6 11% 9 16% 6 11% (* as a subset of the evaluable population) 9 of 76 pts (12%) rapidly progressed without response or stable disease, including 6 pts in whom dex was also added. As of August 2008, the median time to progression (TTP) for pts achieving PR is 34 wks, and for all pts achieving MR is 33 wks. The median TTP for all study pts is 19 wks (range 3 – 103 wks). The median TTP for responders and for all pts has not been met. In a subset analysis of Vel refractory pts (35/57), the reported ORR (□ MR), and median TTP were as follows: Vel Refractory:N= 35 CR PR MR ORR SD Peri + Vel (+/− dex) 1 3% 4 11% 8 23% 13 37% 12 34% Median TTP (wks/range): Responders (n=13) 103 17 (11 – 24) 40 (19 – 76) 37 (11 – 103) 21 (9 – 32) Median TTP (wks/range): All pts (n=35) 23 wks (3 – 103 wks) CONCLUSIONS: Peri in combination with Vel (+/− dex) was generally well tolerated and is remarkably active in a heavily pre-treated, Vel-exposed pt population, with an ORR of 40%, including an ORR of 37% and a median TTP of 9.25 months in responding but previously Vel –refractory pts. Responses have been durable overall with clinical benefit seen, as reflected by an encouraging TTP in this setting. Additional analysis will be reported at the meeting and further trials, including randomized studies earlier in relapsed disease, are planned.

Preclinical and phase I clinical studies with the nonclassical antifolate thymidylate synthase inhibitor nolatrexed dihydrochloride given by prolonged administration in patients with solid tumors.

1998 ◽  
Vol 16 (3) ◽  
pp. 1131-1141 ◽  
Author(s):  
I Rafi ◽  
A V Boddy ◽  
J A Calvete ◽  
G A Taylor ◽  
D R Newell ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Thymidylate Synthase ◽  
High Performance ◽  
Plasma Concentrations ◽  
Maximum Tolerated Dose ◽  
Hematologic Toxicity ◽  
Antitumor Effects

PURPOSE A phase I, multicenter trial of the thymidylate synthase (TS) inhibitor THYMITAQ (nolatrexed dihydrochloride; Agouron Pharmaceuticals, Inc, San Diego, CA) given by 5-day continuous infusion was performed to establish the maximum-tolerated dose (MTD) and to investigate pharmacokinetics, pharmacodynamics, and antitumor effects. METHODS In vitro and in vivo preclinical studies demonstrated increased activity with prolonged nolatrexed exposure. In 32 patients, nolatrexed was given as a 5-day infusion at 96 to 1,040 mg/m2/d for 5 days. Pharmacokinetics were determined from high-performance liquid chromatography (HPLC) analyses of plasma and urine. In addition to studying toxicity, plasma deoxyuridine (UdR) elevations were measured as a marker of TS inhibition. RESULTS The MTD was 904 mg/m2/d for 5 days and the recommended phase II dose is 800 mg/m2/d for 5 days. The dose-limiting toxicity was neutropenia with clinically significant thrombocytopenia and mucositis. These antiproliferative toxicities of nolatrexed were predictable and reversible. A partial response that lasted 3 months occurred in a patient with metastatic colorectal cancer. Pharmacokinetics were nonlinear, with the median plasma clearance (CI) decreasing from 151 mL/min/m2 (range, 124 to 211) at 96 mg/m2/d for 5 days to 49 mL/min/m2 (range, 30 to 84) at 768 mg/ m2/d for 5 days. The half-life (t1/2) was 173 minutes (range, 43 to 784) and 18% (range, 9% to 35%) of the dose was excreted unchanged in the urine. Plasma UdR increased, but returned to pretreatment levels after the end of infusion. Hematologic toxicity was significantly related to nolatrexed plasma concentrations and dose. CONCLUSION Nolatrexed can be safely administered to patients at a dose of 800 mg/m2/d over 5 days by continuous intravenous infusion and this schedule is associated with antitumor effects. The phase II evaluation of nolatrexed is ongoing.

Role of Phase II Enzymes in the Bioactivation of 1,4-Dichlorobenzene and 1,4-Dibromobenzene

1996 ◽  
Vol 24 (4) ◽  
pp. 603-608
Author(s):  
Moreno Paolini ◽  
Laura Pozzetti ◽  
Renata Mesirca ◽  
Andrea Sapone ◽  
Paola Silingardi ◽  
...  
Keyword(s):  
Dna Binding ◽  
Phase I ◽  
Phase Ii ◽  
Covalent Binding ◽  
Fold Increase ◽  
Test System ◽  
Oxidative Enzymes ◽  
Transferase Activity ◽  
Genetic Toxicology

The use of sodium phenobarbital (PB, CYP2B1 inducer) combined with β-naphthoflavone (β-NF, 1A1) to induce certain Phase I reactions in S9 liver fractions is a standard method for conducting short-term bioassays for genotoxicity. However, because post-oxidative enzymes are also able to activate many precarcinogens, we tested the possibility of adapting S9 liver fractions derived from Phase II-induced rodents to the field of genetic toxicology. In this study, S9 liver fractions derived from Swiss albino CD1 mice fed 7.5g/kg 2-(3)-tert-butyl-4-hydroxyanisole (BHA; a monofunctional Phase II-inducer) for 3 weeks, show a clear pattern of induction with an approximately 3.5–9.5-fold increase in glutathione S-transferase activity. In vitro DNA binding of the promutagenic agents, [14C]-l,4-dichlorobenzene (DCB) and [14C]-1,4-dibromobenzene (DBB), is mediated by such metabolic liver preparations and showed a significant increase in covalent binding capability. In some instances, enzyme activity was more elevated when compared to that obtained with traditional (Phase I-induced) S9. Together with DNA binding, the genetic response of these chemicals in the diploid D7 strain of Saccharomyces cerevisiae used as a biological test system, revealed the ability of the BHA-derived preparations to activate the promutagenic agents, as exemplified by the significant enhancement of mitotic gene-conversion (up to 5.2-fold for DCB and 3.4-fold for DBB) and reverse point mutation (up to 3.6-fold for DCB and 2.5-fold for DBB) at a 4mM concentration. This novel metabolising biosystem, with enhanced Phase II activity, is recommended together with a traditional S9, for detecting unknown promutagens in genotoxicity studies. The routine use of either oxidative or post-oxidative S9 increases the responsiveness of the test and can contribute to the identification of promutagens not detected when using traditional protocols.

Intrathecal Mafosfamide: A Preclinical Pharmacology and Phase I Trial

2005 ◽  
Vol 23 (7) ◽  
pp. 1555-1563 ◽  
Author(s):  
Susan M. Blaney ◽  
Frank M. Balis ◽  
Stacey Berg ◽  
Carola A.S. Arndt ◽  
Richard Heideman ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Phase I Trial ◽  
Neoplastic Meningitis ◽  
In Vitro Cytotoxicity ◽  
Pharmacokinetic Studies ◽  
Preclinical Studies ◽  
Phase Ii Trials ◽  
Cytotoxicity Studies

Purpose Preclinical studies of mafosfamide, a preactivated cyclophosphamide analog, were performed to define a tolerable and potentially active target concentration for intrathecal (IT) administration. A phase I and pharmacokinetic study of IT mafosfamide was performed to determine a dose for subsequent phase II trials. Patients and Methods In vitro cytotoxicity studies were performed in MCF-7, Molt-4, and rhabdomyosarcoma cell lines. Feasibility and pharmacokinetic studies were performed in nonhuman primates. These preclinical studies were followed by a phase I trial in patients with neoplastic meningitis. There were five dose levels ranging from 1 mg to 6.5 mg. Serial CSF samples were obtained for pharmacokinetic studies in a subset of patients with Ommaya reservoirs. Results The cytotoxic target exposure for mafosfamide was 10 μmol/L. Preclinical studies demonstrated that this concentration could be easily achieved in ventricular CSF after intraventricular dosing. In the phase I clinical trial, headache was the dose-limiting toxicity. Headache was ameliorated at 5 mg by prolonging the infusion rate to 20 minutes, but dose-limiting headache occurred at 6.5 mg dose with prolonged infusion. Ventricular CSF mafosfamide concentrations at 5 mg exceeded target cytotoxic concentrations after an intraventricular dose, but lumbar CSF concentrations 2 hours after the dose were less than 10 μmol/L. Therefore, a strategy to alternate dosing between the intralumbar and intraventricular routes was tested. Seven of 30 registrants who were assessable for response had a partial response, and six had stable disease. Conclusion The recommended phase II dose for IT mafosfamide, administered without concomitant analgesia, is 5 mg over 20 minutes.

Effects of Ofloxacin Administration on the Reliability of Urine Glucose Testing

1996 ◽  
Vol 30 (5) ◽  
pp. 469-472
Author(s):  
Tsong-Mei Tsai ◽  
Brian F Shea ◽  
Paul F Souney ◽  
Fred G Volinsky ◽  
Joseph M Scavone ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Tertiary Care ◽  
Urine Samples ◽  
Care Hospital ◽  
Open Label ◽  
Urine Glucose ◽  
Glucose Testing

OBJECTIVE: TO study the effects of ofloxacin on the reliability of urine glucose testing. DESIGN: Open-label, nonrandomized. SETTING: A university-affiliated tertiary care hospital, ambulatory clinic. PARTICIPANTS: Ten healthy volunteers (8 men and 2 women) aged 22-39 years. MAIN OUTCOME MEASURES: Phase I (in vitro) involved the addition of selected amounts of ofloxacin to a set of standard 50-mL urine samples prepared to simulate glycosuria. Phase II (in vivo) involved the oral administration of ofloxacin 400 mg to 10 subjects. Urine was collected: (1) immediately predose, (2) pooled 0–4 hours postdose, and (3) pooled 4–8 hours postdose. Known glucose concentrations were then added to these samples. Clinitest and Diastix tests were performed on all samples. The accuracy of these tests in determining glucose concentrations was compared among urine samples taken before and after ofloxacin dosing. RESULTS: None of the ofloxacin concentrations in phase I (0,25,50, 100, 200,400, and 800 μg/mL) influenced these testing methods at the urine glucose concentrations of 0.0%, 0.5%, 1%, and 2%. Likewise, the accuracy of these two tests was unaffected by ofloxacin administration in phase II. CONCLUSIONS: In single-dose administration, ofloxacin does not interfere with Clinitest or Diastix for determining urine glucose concentrations. Supported by a grant from the RW Johnson Pharmaceutical Research Institute. Presented in abstract form at the American College of Clinical Pharmacy 1994 Winter Practice and Research Forum, February 6–9, 1994, San Diego. CA.

scholarly journals Critical role of the extracellular signal–regulated kinase–MAPK pathway in osteoblast differentiation and skeletal development

2007 ◽  
Vol 176 (5) ◽  
pp. 709-718 ◽  
Author(s):  
Chunxi Ge ◽  
Guozhi Xiao ◽  
Di Jiang ◽  
Renny T. Franceschi
Keyword(s):  
Transcriptional Activity ◽  
Mapk Pathway ◽  
Skeletal Development ◽  
Critical Role ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

The extracellular signal–regulated kinase (ERK)–mitogen-activated protein kinase (MAPK) pathway provides a major link between the cell surface and nucleus to control proliferation and differentiation. However, its in vivo role in skeletal development is unknown. A transgenic approach was used to establish a role for this pathway in bone. MAPK stimulation achieved by selective expression of constitutively active MAPK/ERK1 (MEK-SP) in osteoblasts accelerated in vitro differentiation of calvarial cells, as well as in vivo bone development, whereas dominant-negative MEK1 was inhibitory. The involvement of the RUNX2 transcription factor in this response was established in two ways: (a) RUNX2 phosphorylation and transcriptional activity were elevated in calvarial osteoblasts from TgMek-sp mice and reduced in cells from TgMek-dn mice, and (b) crossing TgMek-sp mice with Runx2+/− animals partially rescued the hypomorphic clavicles and undemineralized calvaria associated with Runx2 haploinsufficiency, whereas TgMek-dn; Runx2+/− mice had a more severe skeletal phenotype. This work establishes an important in vivo function for the ERK–MAPK pathway in bone that involves stimulation of RUNX2 phosphorylation and transcriptional activity.

scholarly journals Positively Correlated CD47 Activation and Autophagy in Umbilical Cord Blood-Derived Mesenchymal Stem Cells during Senescence

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Gee-Hye Kim ◽  
Yun Kyung Bae ◽  
Ji Hye Kwon ◽  
Miyeon Kim ◽  
Soo Jin Choi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Cell Growth ◽  
Cell Therapy ◽  
Critical Role ◽  
Therapeutic Effects ◽  
Stem Cell Maintenance ◽  
Selection Of

Autophagy plays a critical role in stem cell maintenance and is related to cell growth and cellular senescence. It is important to find a quality-control marker for predicting senescent cells. This study verified that CD47 could be a candidate to select efficient mesenchymal stem cells (MSCs) to enhance the therapeutic effects of stem cell therapy by analyzing the antibody surface array. CD47 expression was significantly decreased during the expansion of MSCs in vitro ( p < 0.01 ), with decreased CD47 expression correlated with accelerated senescence phenotype, which affected cell growth. UCB-MSCs transfected with CD47 siRNA significantly triggered the downregulation of pRB and upregulation of pp38, which are senescence-related markers. Additionally, autophagy-related markers, ATG5, ATG12, Beclin1, and LC3B, revealed significant downregulation with CD47 siRNA transfection. Furthermore, autophagy flux following treatment with an autophagy inducer, rapamycin, has shown that CD47 is a key player in autophagy and senescence to maintain and regulate the growth of MSCs, suggesting that CD47 may be a critical key marker for the selection of effective stem cells in cell therapy.

scholarly journals p120 catenin induces opposing effects on tumor cell growth depending on E-cadherin expression

2008 ◽  
Vol 183 (4) ◽  
pp. 737-749 ◽  
Author(s):  
Edwin Soto ◽  
Masahiro Yanagisawa ◽  
Laura A. Marlow ◽  
John A. Copland ◽  
Edith A. Perez ◽  
...  
Keyword(s):  
Cell Growth ◽  
Tumor Cell ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Tumor Cell Growth ◽  
P120 Catenin ◽  
Opposing Effects ◽  
E Cadherin

p120 catenin regulates the activity of the Rho family guanosine triphosphatases (including RhoA and Rac1) in an adhesion-dependent manner. Through this action, p120 promotes a sessile cellular phenotype when associated with epithelial cadherin (E-cadherin) or a motile phenotype when associated with mesenchymal cadherins. In this study, we show that p120 also exerts significant and diametrically opposing effects on tumor cell growth depending on E-cadherin expression. Endogenous p120 acts to stabilize E-cadherin complexes and to actively promote the tumor-suppressive function of E-cadherin, potently inhibiting Ras activation. Upon E-cadherin loss during tumor progression, the negative regulation of Ras is relieved; under these conditions, endogenous p120 promotes transformed cell growth both in vitro and in vivo by activating a Rac1–mitogen-activated protein kinase signaling pathway normally activated by the adhesion of cells to the extracellular matrix. These data indicate that both E-cadherin and p120 are important regulators of tumor cell growth and imply roles for both proteins in chemoresistance and targeted therapeutics.

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