Teemu T Junttila

University of Turku, Turku, Province of Western Finland, Finland

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Publications (27)182.97 Total impact

  • Science translational medicine 05/2015; 7(287). · 14.41 Impact Factor
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    ABSTRACT: Bispecific antibodies and antibody fragments in various formats have been explored as a means to recruit cytolytic T cells to kill tumor cells. Encouraging clinical data have been reported with molecules such as the anti-CD19/CD3 bispecific T cell engager (BiTE) blinatumomab. However, the clinical use of many reported T cell-recruiting bispecific modalities is limited by liabilities including unfavorable pharmacokinetics, potential immunogenicity, and manufacturing challenges. We describe a B cell-targeting anti-CD20/CD3 T cell-dependent bispecific antibody (CD20-TDB), which is a full-length, humanized immunoglobulin G1 molecule with near-native antibody architecture constructed using "knobs-into-holes" technology. CD20-TDB is highly active in killing CD20-expressing B cells, including primary patient leukemia and lymphoma cells both in vitro and in vivo. In cynomolgus monkeys, CD20-TDB potently depletes B cells in peripheral blood and lymphoid tissues at a single dose of 1 mg/kg while demonstrating pharmacokinetic properties similar to those of conventional monoclonal antibodies. CD20-TDB also exhibits activity in vitro and in vivo in the presence of competing CD20-targeting antibodies. These data provide rationale for the clinical testing of CD20-TDB for the treatment of CD20-expressing B cell malignancies. Copyright © 2015, American Association for the Advancement of Science.
    Science translational medicine 05/2015; 7(287):287ra70. DOI:10.1126/scitranslmed.aaa4802 · 14.41 Impact Factor
  • Cancer Research 05/2015; 75(9 Supplement):S1-07-S1-07. DOI:10.1158/1538-7445.SABCS14-S1-07 · 9.28 Impact Factor
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    ABSTRACT: Antibody dependent cellular cytotoxicity (ADCC) is a key mechanism by which therapeutic antibodies mediate their anti-tumor effects. Absence of fucose on the heavy chain of the antibody increases the affinity between the antibody and FcγRIIIa, which results in increased in vitro and in vivo ADCC compared to the fucosylated form. However, the cellular and molecular mechanisms responsible for increased ADCC are unknown. Through a series of biochemical and cellular studies, we find that human NK cells stimulated with afucosylated antibody exhibit enhanced activation of proximal FcγRIIIa signaling and downstream pathways, as well as enhanced cytoskeletal rearrangement and degranulation, relative to stimulation with fucosylated antibody. Furthermore, analysis of the interaction between human NK cells and targets using a high-throughput microscope-based antibody-dependent cytotoxicity assay show that afucosylated antibodies increase the number of NK cells capable of killing multiple targets and the rate with which targets are killed. Together, we conclude that the increase in affinity between afucosylated antibodies and FcγRIIIa enhances activation of signaling molecules promoting cytoskeletal rearrangement and degranulation, which, in turn, potentiates the cytotoxic characteristics of NK cells to increase efficiency of ADCC.
    11/2014; 3(2). DOI:10.1158/2326-6066.CIR-14-0125
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    ABSTRACT: Clinical results from the latest strategies for T-cell activation in cancer have fired interest in combination immunotherapies that can fully engage T-cell immunity. In this study, we describe a trastuzumab-based bispecific antibody, HER2-TDB, which targets HER2 and conditionally activates T cells. HER2-TDB specifically killed HER2-expressing cancer cells at low picomolar concentrations. Because of its unique mechanism of action, which is independent of HER2 signaling or chemotherapeutic sensitivity, HER2-TDB eliminated cells refractory to currently approved HER2 therapies. HER2-TDB exhibited potent antitumor activity in four preclinical model systems, including MMTV-huHER2 and huCD3 transgenic mice. PD-L1 expression in tumors limited HER2-TDB activity, but this resistance could be reversed by anti-PD-L1 treatment. Thus, combining HER2-TDB with anti-PD-L1 yielded a combination immunotherapy that enhanced tumor growth inhibition, increasing the rates and durability of therapeutic response. Cancer Res; 74(19); 1-11. ©2014 AACR.
    Cancer Research 09/2014; 74(19). DOI:10.1158/0008-5472.CAN-13-3622-T · 9.28 Impact Factor
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    ABSTRACT: OBJECTIVE: ErbB4 is a member of the ErbB subfamily of receptor tyrosine kinases with a poorly understood biological role in ovarian cancer. Here, we have addressed the expression, subcellular localization, and prognostic relevance of ErbB4 and its alternatively spliced isoforms in serous ovarian adenocarcinoma. METHODS: A tissue microarray including 482 samples was analyzed by immunohistochemistry, and a series of 198 samples by isoform-specific real-time RT-PCR. The data were statistically analyzed for associations with clinicopathological markers and survival. The functional effect of expressing the relevant ErbB4 isoforms in ovarian cancer cells was addressed by measuring colony formation in soft agar. RESULTS: While ErbB4 immunoreactivity was present in 90% of the samples, total ErbB4 protein expression was not significantly associated with prognostic markers. However, real-time RT-PCR analysis of serous ovarian cancer samples indicated the presence of two alternatively spliced cytoplasmic isoforms of ERBB4, CYT-1 and CYT-2, previously demonstrated to mediate significantly different cellular activities. Expression of CYT-1, but not of CYT-2, was significantly associated with tumor grade (P = 0.014) and overall survival (P = 0.0028). CYT-1 expression was also an independent prognostic factor (P = 0.021) in multivariate analysis of survival. Consistent with a biological effect specific for the one isoform, overexpression of ErbB4 CYT-1, but not of ErbB4 CYT-2, increased anchorage-independent growth of ovarian adenocarcinoma cells in vitro. CONCLUSIONS: These results suggest that expression of a specific ErbB4 isoform, CYT-1, is associated with poor survival and enhanced growth in serous ovarian cancer.
    Gynecologic Oncology 01/2013; 129(1). DOI:10.1016/j.ygyno.2012.12.044 · 3.69 Impact Factor
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    ABSTRACT: Trastuzumab (Herceptin(®)) is currently used as a treatment for patients whose breast tumors overexpress HER2/ErbB2. Trastuzumab-DM1 (T-DM1, trastuzumab emtansine) is designed to combine the clinical benefits of trastuzumab with a potent microtubule-disrupting drug, DM1 (a maytansine derivative). Currently T-DM1 is being tested in multiple clinical trials. The mechanisms of action for trastuzumab include inhibition of PI3K/AKT signaling pathway, inhibition of HER-2 shedding and Fcγ receptor mediated engagement of immune cells, which may result in antibody-dependent cellular cytotoxicity (ADCC). Here we report that T-DM1 retains the mechanisms of action of unconjugated trastuzumab and is active against lapatinib resistant cell lines and tumors.
    Breast Cancer Research and Treatment 07/2011; 128(2):347-56. DOI:10.1007/s10549-010-1090-x · 4.20 Impact Factor
  • Teemu T Junttila · Minna Tanner · Jorma Isola
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    ABSTRACT: First generation antibody drugs recognize the cancer cell, slow down the signaling of cell growth and activate the defense response. Second generation antibody drugs contain conjugated cytotoxic agents that are activated upon entry into the cancer cell. Trastuzumab has become established among the first generation antibody drugs utilized in breast cancer therapy, and its derivative trastuzumab-DM1 is the first antibody-drug conjugate currently in clinical trials for breast cancer. Trastuzumab acts as an antibody and transports into the cancer cell the cytotoxic agent DM1, which becomes activated there. Targeted cytotoxic drugs are under development for the treatment of many different types of cancer.
    Duodecim; lääketieteellinen aikakauskirja 01/2011; 127(4):343-9.
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    ABSTRACT: The enhancement of immune effector functions has been proposed as a potential strategy for increasing the efficacy of therapeutic antibodies. Here, we show that removing fucose from trastuzumab (Herceptin) increased its binding to FcgammaRIIIa, enhanced antibody-dependent cell-mediated cytotoxicity, and more than doubled the median progression-free survival when compared with conventional trastuzumab in treating preclinical models of HER2-amplified breast cancer. Our results show that afucosylated trastuzumab has superior efficacy in treating in vivo models of HER2-amplified breast cancer and support the development of effector function-enhanced antibodies for solid tumor therapy.
    Cancer Research 06/2010; 70(11):4481-9. DOI:10.1158/0008-5472.CAN-09-3704 · 9.28 Impact Factor
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    ABSTRACT: Herceptin (trastuzumab) is the backbone of HER2-directed breast cancer therapy and benefits patients in both the adjuvant and metastatic settings. Here, we describe a mechanism of action for trastuzumab whereby antibody treatment disrupts ligand-independent HER2/HER3 interactions in HER2-amplified cells. The kinetics of dissociation parallels HER3 dephosphorylation and uncoupling from PI3K activity, leading to downregulation of proximal and distal AKT signaling, and correlates with the antiproliferative effects of trastuzumab. A selective and potent PI3K inhibitor, GDC-0941, is highly efficacious both in combination with trastuzumab and in the treatment of trastuzumab-resistant cells and tumors.
    Cancer cell 06/2009; 15(5):429-40. DOI:10.1016/j.ccr.2009.03.020 · 23.89 Impact Factor
  • EJC Supplements 10/2008; 6(12):163-163. DOI:10.1016/S1359-6349(08)72449-2 · 9.39 Impact Factor
  • EJC Supplements 10/2008; 6(12):101-101. DOI:10.1016/S1359-6349(08)72250-X · 9.39 Impact Factor
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    ABSTRACT: Suppression of tumor growth by inhibition of ErbB receptor signaling is well documented. However, relatively little is known about the ErbB signaling system in the regulation of angiogenesis, a process necessary for tumor growth. We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) is expressed by vascular endothelial cells (EC) and promotes endothelial recruitment of vascular smooth muscle cells (SMC). To assess whether other members of the EGF-family regulate angiogenesis, the expression of 10 EGF-like growth factors in primary ECs and SMCs was analyzed. In addition to HB-EGF, neuregulin-1 (NRG-1) was expressed in ECs in vitro and in vivo. Endothelial NRG-1 was constitutively processed to soluble extracellular and intracellular signaling fragments, and its expression was induced by hypoxia. NRG-1 was angiogenic in vivo in mouse corneal pocket and chicken chorioallantoic membrane (CAM) assays. However, consistent with the lack of NRG-1 receptors in several primary EC lines, NRG-1 did not directly stimulate cellular responses in cultured ECs. In contrast, NRG-1 promoted EC responses in vitro and angiogenesis in CAM in vivo by mechanisms dependent on VEGF-A and VEGFR-2. These results indicate that NRG-1 is expressed by ECs and regulates angiogenesis by mechanisms involving paracrine up-regulation of VEGF-A.
    Experimental Cell Research 09/2007; 313(13):2896-909. DOI:10.1016/j.yexcr.2007.03.042 · 3.37 Impact Factor
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    ABSTRACT: Chromogenic in situ hybridization (CISH) was used to detect amplification of the epidermal growth factor receptor (EGFR) gene in tissue microarrays of tumours derived from 287 patients with grade II-IV diffuse astrocytomas. Amplification was found in 32% of the tumours with a highly significant association with histological grade (4% in grade II, 21% in grade III and 39% in grade IV; P < 0.001). Amplification of the EGFR gene was more common in primary than in secondary glioblastomas (41%vs. 16%, P = 0.033). Overexpression of EGFR mRNA and protein (wild-type and vIII variant) was found to correlate with EGFR gene amplification (P = 0.028, P = 0.035 and P = 0.014 respectively), but wild-type EGFR protein was also frequently overexpressed in tumours without EGFR gene amplification. Patients with older age (P < 0.001) and tumours with lack of p53 overexpression (P = 0.03) and higher apoptosis rate (P < 0.001) had significantly more EGFR gene amplifications than their counterparts. No such correlation with apoptosis was found in glioblastomas. The survival of patients with EGFR gene-amplified grade III tumours was significantly shorter than in those with grade III non-amplified tumours (P = 0.03). No such difference was noted in glioblastomas (grade IV tumours). Our data verify the central role of EGFR in the pathobiology of astrocytic tumours, and highlight the advantages of CISH as a simple and practical assay to screen for EGFR gene amplification in astrocytic tumours.
    Neuropathology and Applied Neurobiology 09/2006; 32(4):441-50. DOI:10.1111/j.1365-2990.2006.00758.x · 4.97 Impact Factor
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    ABSTRACT: The epidermal growth factor receptor (EGFR) inhibitor gefitinib (Iressa) has shown antitumor activity in clinical trials against cancers, such as non-small cell lung cancer and head and neck squamous cell carcinoma (HNSCC). Research on non-small cell lung cancer has elucidated factors that may predict response to gefitinib. Less is known about molecular markers that may predict response to gefitinib in HNSCC patients. We analyzed possible associations of responsiveness to gefitinib with molecular markers of the EGFR/ErbB receptor family signaling pathway using 10 established HNSCC lines in vitro. IC50 of gefitinib sensitivity was determined using clonogenic survival assays. ErbB signaling was assessed by Western and real-time reverse transcription-PCR analyses of EGFR, ErbB2, ErbB3, and ErbB4 expression levels as well as by phosphorylation analysis of pEGFR, pErbB2, pErbB3, pAkt, and pErk. EGFR sequences encoding kinase domain and EGFR gene copy numbers were determined by cDNA sequencing and real-time PCR, respectively. Finally, responsiveness to gefitinib was compared with responsiveness to the anti-EGFR antibody cetuximab (Erbitux). Expression levels of pErbB2 (P = 0.02) and total ErbB3 protein (P = 0.02) associated with resistance to gefitinib. Combining gefitinib with pertuzumab (Omnitarg), an antibody targeting ErbB2 heterodimerization, provided additional growth-inhibitory effect over gefitinib alone on relatively gefitinib-resistant HNSCC cell lines. The same markers did not predict resistance to cetuximab. In contrast, a similar trend suggesting association between EGFR gene copy number and drug sensitivity was observed for both gefitinib (P = 0.0498) and cetuximab (P = 0.053). No activating EGFR mutations were identified. EGFR amplification may predict sensitivity to gefitinib in HNSCC. However, other EGFR/ErbB receptor family members than EGFR may contribute to resistance to gefitinib. ErbB2 and ErbB3 may have potential as predictive markers and as therapeutic targets for combination therapy in treatment of HNSCC with gefitinib.
    Clinical Cancer Research 08/2006; 12(13):4103-11. DOI:10.1158/1078-0432.CCR-05-2404 · 8.19 Impact Factor
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    ABSTRACT: The ErbB1 and ErbB2 receptors are oncogenes with therapeutic significance in human cancer, whereas the transforming potential of the related ErbB4 receptor has remained controversial. Here, we have addressed whether four alternatively spliced ErbB4 isoforms differ in regulating cellular responses relevant for tumor growth. We show that the two tumor necrosis factor-alpha converting enzyme (TACE)-cleavable ErbB4 isoforms (the juxtamembrane [JM]-a isoforms) were overexpressed in a subset of primary human breast cancers together with TACE. The overexpression of the JM-a cytoplasmic (CYT)-2 ErbB4 isoform promoted ErbB4 phosphorylation, survival of interleukin-3-dependent cells, and proliferation of breast cancer cells even in the absence of ligand stimulation, whereas activation of the other three ErbB4 isoforms required ligand stimulation. Ligand-independent cellular responses to ErbB4 JM-a CYT-2 overexpression were regulated by both tyrosine kinase activity and a two-step proteolytic generation of an intracellular receptor fragment involving first a TACE-like proteinase, followed by gamma-secretase activity. These data suggest a novel transforming mechanism for the ErbB4 receptor in human breast cancer that is 1) specific for a single receptor isoform and 2) depends on proteinase cleavage and kinase activity but not ligand activation of the receptor.
    Molecular Biology of the Cell 02/2006; 17(1):67-79. DOI:10.1091/mbc.E05-05-0402 · 4.55 Impact Factor
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    ABSTRACT: DNA topoisomerase I (Topo I) is a molecular target for the anticancer agent topotecan in the treatment of small cell lung cancer and ovarian carcinomas. However, the molecular mechanisms by which topotecan treatment inhibits cancer cell proliferation are unclear. We describe here the identification of Topo I as a novel endogenous interaction partner for transcription factor c-Jun. Reciprocal coimmunoprecipitation analysis showed that Topo I and c-Jun interact in transformed human cells in a manner that is dependent on JNK activity. c-Jun target gene epidermal growth factor receptor (EGFR) was identified as a novel gene whose expression was specifically inhibited by topotecan. Moreover, Topo I overexpression supported c-Jun-mediated reporter gene activation and both genetic and chemical inhibition of c-Jun converted cells resistant to topotecan-elicited EGFR downregulation. Topotecan-elicited suppression of proliferation was rescued by exogenously expressed EGFR. Furthermore, we demonstrate the cooperation of the JNK-c-Jun pathway, Topo I, and EGFR in the positive regulation of HT-1080 cell proliferation. Together, these results have identified transcriptional coactivator Topo I as a first endogenous cofactor for c-Jun in the regulation of cell proliferation. In addition, the results of the present study strongly suggest that inhibition of EGFR expression is a novel mechanism by which topotecan inhibits cell proliferation in cancer therapy.
    Molecular and Cellular Biology 07/2005; 25(12):5040-51. DOI:10.1128/MCB.25.12.5040-5051.2005 · 5.04 Impact Factor
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    ABSTRACT: HER-2/neu gene amplification has predictive value in breast cancer patients responding to trastuzumab. We wanted to investigate the frequency and clinical significance of HER-2/neu amplification in gastric carcinoma. The frequency of HER-2/neu and Topoisomerase IIalpha gene amplification was studied in adenocarcinomas of the stomach (n=131) and the gastroesophageal junction (n=100) by chromogenic in situ hybridization (CISH). Sensitivity of a gastric cancer cell line N87 with HER-2/neu amplification to trastuzumab was studied by a cell viability assay and compared with that of a HER-2 amplified breast cancer cell line SKBR-3. Growth inhibition of N87 cells was also verified in vivo in N87 xenograft tumors. HER-2/neu amplification was present in 16 (12.2%) of the 131 gastric and in 24 (24.0%) of the 100 gastroesophageal adenocarcinomas. Co-amplification of Topoisomerase IIalpha was present in the majority of gastric (63%) and esophagogastric junction cancers (68%) with HER-2/neu amplification. HER-2/neu amplification was more common in the intestinal histologic type of gastric cancer (21.5%) than in the diffuse (2%) or the mixed/anaplastic type (5%, P=0.0051), but it was not associated with gender, age at diagnosis or clinical stage. Presence of HER-2/neu amplification was associated with poor carcinoma-specific survival (P=0.0089). HER-2/neu targeting antibody trastuzumab inhibited the growth of a p185(HER-2/neu) overexpressing gastric and breast carcinoma cell lines (N87 and SKBR-3) with equal efficacy. HER-2/neu amplification is common in the intestinal type of gastric carcinoma, and it is associated with a poor outcome. HER-2 might be a useful target in this disease, and this hypothesis deserves to be investigated in clinical trials.
    Annals of Oncology 03/2005; 16(2):273-8. DOI:10.1093/annonc/mdi064 · 6.58 Impact Factor
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    ABSTRACT: ErbB1 and ErbB2 receptors are well-characterized targets for anticancer drugs, but the clinical relevance of the related ErbB4 receptor is unknown. Here, we have assessed the clinical significance of the proteolytically cleavable ErbB4 isoforms in breast cancer patients and investigated their functions in vitro. The expression of transcripts encoding the cleavable ErbB4 isoforms associated with estrogen receptor-alpha (ER) expression (P < 0.001) and a high histologic grade of differentiation (P </= 0.002) in real-time reverse transcription-PCR analysis of 62 breast cancer samples. Despite high ErbB4 mRNA expression levels in a subset of samples, ErbB4 gene amplification was not observed. High ErbB4 protein expression levels, as assessed by immunohistochemistry, associated with a favorable outcome in ER-positive cases from a series of 458 breast cancer patients (P = 0.01), whereas no association between ErbB4 expression and survival was found among women with ER-negative cancer (P = 0.86). However, nuclear ErbB4 immunoreactivity was associated with poor survival as compared with women whose cancer had membranous ErbB4 staining (P = 0.04). In vitro, overexpression of a cleavable ErbB4 isoform in ER-positive breast cancer cells resulted in translocation of a proteolytically released intracellular ErbB4 receptor fragment into the nucleus, as well as, enhanced proliferation, anchorage-independent growth, and estrogen response element-mediated transcriptional activity. These results suggest that the association of ErbB4 expression with clinical outcome is dependent on the subcellular localization of ErbB4 and that a proteinase-cleavable ErbB4 isoform promotes growth of ER-positive breast cancer and enhances ER-mediated gene transcription.
    Cancer Research 02/2005; 65(4):1384-93. DOI:10.1158/0008-5472.CAN-04-3150 · 9.28 Impact Factor
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    ABSTRACT: Clinical resistance to the HER-2 oncogene-targeting drug trastuzumab (Herceptin) exists, but studies of the resistance mechanisms are hampered by the lack of suitable experimental model systems. We established a carcinoma cell line (designated JIMT-1) from a pleural metastasis of a 62-year old patient with breast cancer who was clinically resistant to trastuzumab. JIMT-1 cells grow as an adherent monolayer and form xenograft tumors in nude mice. JIMT-1 cells have an amplified HER-2 oncogene, which showed no identifiable mutations in its coding sequence. JIMT-1 cells overexpress HER-2 mRNA and protein, and the levels of HER-1, HER-3, and HER-4 mRNA and protein were similar to the trastuzumab-sensitive cell line SKBR-3. The cell line lacks expression of hormone receptors (estrogen receptors and progesterone receptors) and is phenotypically of epithelial progenitor cell origin, as evidenced by immunohistochemical positivity for both cytokeratins 5/14 and 8/18. JIMT-1 cells were insensitive to trastuzumab and another HER-2-inhibiting drug, pertuzumab (2C4), in vitro and in xenograft tumors. Small molecule tyrosine kinase inhibitors Ci1033 and ZD1839 inhibited the JIMT-1 cell growth but to a lesser degree than in trastuzumab-sensitive BT-474 cells. The lack of growth inhibition was rationalized by the unaltered Akt phosphorylation in JIMT-1 cells. Erk1/2 phosphorylation was slightly reduced but still evident in JIMT-1 cells. We conclude that the JIMT-1 cell line provides a valuable experimental model for studies of new trastuzumab-resistance mechanisms.
    Molecular Cancer Therapeutics 01/2005; 3(12):1585-92. · 6.11 Impact Factor

Publication Stats

2k Citations
182.97 Total Impact Points

Institutions

  • 2000–2013
    • University of Turku
      • • Department of Medical Biochemistry and Genetics
      • • MediCity Research Laboratory
      Turku, Province of Western Finland, Finland
  • 2002
    • St. Jude Children's Research Hospital
      • Department of Developmental Neurobiology
      Memphis, Tennessee, United States