-
Takashi Ninomiya,
Nagio Takigawa,
Eiki Ichihara,
Nobuaki Ochi,
Toshi Murakami,
Yoshihiro Honda, Toshio Kubo,
Daisuke Minami,
Kenichiro Kudo,
Mitsune Tanimoto,
Katsuyuki Kiura
[show abstract]
[hide abstract]
ABSTRACT: An irreversible ErbB family blocker is expected to inhibit tumors with activating epidermal growth factor receptor (EGFR) mutations more strongly than reversible EGFR tyrosine kinase inhibitors and to overcome acquired resistance to the T790M secondary mutation. Eleven-week-old transgenic mice with Egfr exon 19 deletion mutation were treated with afatinib, gefitinib, or vehicle for 4 weeks. All mice were sacrificed at 15 weeks of age, and the number of superficial left lung tumors with a long axis exceeding 1 mm was counted. The afatinib-treated group had significantly fewer tumors than the vehicle group (P < 0.01) and tended to have fewer tumors than the gefitinib-treated group (P = 0.06). Pathologically, gefitinib-treated mice had clearer, more nodular tumors than afatinib-treated mice. Immunoblotting showed that afatinib suppressed not only pEGFR but also pHER2, and induced apoptosis for longer periods than gefitinib. Subsequently, when each drug was administered 5 days per week until death, afatinib significantly enhanced mouse survival compared with gefitinib (median survival time: 456 days versus 376.5 days; logrank test, P < 0.01). Finally, the combination of afatinib with bevacizumab was found to be superior to either drug alone in exon 19 deletion/T790M and L858R/T790M xenograft tumors. Overall, afatinib was more potent than gefitinib in tumors harboring an exon 19 deletion mutation, and the combination of afatinib with bevacizumab efficiently suppressed tumors harboring the T790M secondary mutation.
Molecular Cancer Therapeutics 02/2013; · 5.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Tumors are presumed to contain a small population of cancer stem cells (CSCs) that initiate tumor growth and promote tumor spreading. Multidrug resistance in CSCs is thought to allow the tumor to evade conventional therapy. This study focused on expression of CD133 and CD87 because CD133 is a putative marker of CSCs in some cancers including lung, and CD87 is associated with a stem-cell-like property in SCLC. Six SCLC cell lines were used. The expression levels of CD133 and CD87 were analyzed by real-time quantitative reverse transcription-polymerase chain reaction and flow cytometry. CD133+/- and CD87+/- cells were isolated by flow cytometry. The drug sensitivities were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Non-obese diabetic/severe combined immunodeficiency mice were used for the tumor formation assay. SBC-7 cells showed the highest expression levels of both CD133 and CD87 among the cell lines. CD133-/CD87-, CD133+/CD87-, and CD133-/CD87+ cells were isolated from SBC-7 cells; however, CD133+/CD87+ cells could not be obtained. Both CD133+/CD87- and CD133-/CD87+ subpopulations showed a higher resistance to etoposide and paclitaxel and greater re-populating ability than the CD133-/CD87- subpopulation. CD133+/CD87- cells contained more G0 quiescent cells than CD133-/CD87- cells. By contrast, CD133-/CD87- cells showed the highest tumorigenic potential. In conclusion, both CD133 and CD87 proved to be inadequate markers for CSCs; however, they might be beneficial for predicting resistance to chemotherapy.
Cancer Science 10/2012; · 3.33 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A 34-year-old Japanese woman presented with left supraclavicular lymph node swelling. Computed tomography scans revealed a mass on the left lower lobe, pulmonary nodules, and pleural effusion. A lymph node biopsy revealed large-cell carcinoma with an epidermal growth factor receptor (EGFR) deletion mutation, L747-T751 in exon 19. Although malignant pleural effusions carried the same EGFR mutation, progressive pleural effusions after treatment with chemotherapy, gefitinib, and erlotinib did not show any EGFR mutation. A cell line established from the pleural effusion 3 days before the patient expired also did not harbor the EGFR mutation. Histological sections of the lymph node of the patient were similar to those of the xenograft tumor of the cell line. There may be genetic heterogeneity in EGFR mutant tumors.
Lung cancer (Amsterdam, Netherlands) 07/2012; 78(1):121-4. · 3.14 Impact Factor
-
Daijiro Harada,
Nagio Takigawa,
Nobuaki Ochi,
Takashi Ninomiya,
Masayuki Yasugi, Toshio Kubo,
Hiromasa Takeda,
Eiki Ichihara,
Kadoaki Ohashi,
Saburo Takata,
Mitsune Tanimoto,
Katsuyuki Kiura
[show abstract]
[hide abstract]
ABSTRACT: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, such as gefitinib and erlotinib, are effective for non-small cell lung cancer with activating EGFR mutations. However, even in patients with an initial dramatic response to such a drug, acquired resistance develops after 6-12 months. A secondary mutation of T790M in EGFR and amplification of the MET gene account for this resistance; however, the mechanism(s) of approximately 30% of acquired resistance cases remain unknown. We established an erlotinib-resistant lung cancer cell line named PC-9/ER3 that harbors an EGFR mutation after continuously exposing PC-9 cells to erlotinib. PC-9/ER3 cells were 136-fold more resistant to erlotinib than the parental cells. Although the PC-9/ER3 cells did not carry the T790M mutation or MET amplification and had similar levels of phosphorylated (p) STAT3, pJAK2 increased in the resistant cells. It was found in the present study that 3-12 h of exposure to erlotinib in both cell lines did not affect pJAK2 expression, but did result in increased pSTAT3 expression. pAkt in PC-9/ER3 cells was less suppressed than in PC-9 cells, although pEGFR and pMAPK were markedly suppressed in both cell lines. The combined treatment of erlotinib plus a JAK2 inhibitor (JSI-124) suppressed pAkt in PC-9/ER3 cells. Similarly, the combination of erlotinib plus JSI-124 or siRNA against JAK2 restored sensitivity to erlotinib in PC-9/ER3 cells. The combination of erlotinib plus JSI-124 was also effective for reducing PC-9/ER3 tumors in a murine xenograft model. Our results suggest that the activation of JAK2 partially accounts for acquired erlotinib resistance.(Cancer Sci, doi: 10.1111/j.1349-7006.2012.02363.x, 2012).
Cancer Science 06/2012; 103(10):1795-802. · 3.33 Impact Factor
-
Saburo Takata,
Nagio Takigawa,
Yoshihiko Segawa, Toshio Kubo,
Kadoaki Ohashi,
Toshiyuki Kozuki,
Norihiro Teramoto,
Motohiro Yamashita,
Shinichi Toyooka,
Mitsune Tanimoto,
Katsuyuki Kiura
[show abstract]
[hide abstract]
ABSTRACT: Bronchioloalveolar carcinoma (BAC) pattern is often seen at the margin of invasive adenocarcinomas. We investigated EGFR signaling abnormalities involved in the progression of adenocarcinoma. Fifty tumors were obtained from patients who underwent surgery for lung adenocarcinoma seen as dense areas in ground glass opacity on computed tomography. Six, 18, and 26 tumors <1cm, 1-2 cm, and ≥2 cm in diameter, respectively, were analyzed. Of the 24 tumors ≤2 cm in diameter, nine were preinvasive and 15 were invasive. EGFR, pAKT, and pMAPK were overexpressed in the center of the adenocarcinoma compared to the BAC component (p<0.01) by immunohistochemistry, while pSTAT3 expression was reversed (p=0.017). In the tumors ≤2 cm in diameter, pSTAT3 expression in the central area was higher in preinvasive tumors than in invasive tumors (p=0.005). pSTAT3 was identified in the BAC component of 88% of the EGFR mutant (n=17) and 82% of the wild-type tumors (n=33). Transgenic mice expressing delE748-A752 EGFR and two lung cancer cell lines (PC-9 mutant and A549 wild-type EGFR) were also investigated. In transgenic mice, pSTAT3 was overexpressed in the BAC component around the adenocarcinoma center. Two lung cancer cell lines that overexpressed pSTAT3 were equally sensitive to a JAK2/STAT3 inhibitor (JSI-124). The role of STAT3 in the progression of adenocarcinoma should be further pursued.
Lung cancer (Amsterdam, Netherlands) 06/2011; 75(1):24-9. · 3.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A 51-year-old female presented with left facial palsy. She had adenocarcinoma of the lung with multiple brain metastases. The primary tumor regressed after treatment with gefitinib, however, neurological symptoms progressed rapidly because of meningeal carcinomatosis, when a deletion mutation in exon 19 of the epidermal growth factor receptor in cells from her cerebrospinal fluid was detected. After performing lumbo-peritoneal shunting, her symptoms improved dramatically and she had been well without peritoneal dissemination for 15 months, continuing gefitinib treatment. Finally, she died 18 months after lumbo-peritoneal shunting. A T790M acquired-resistance mutation in exon 20 of the epidermal growth factor receptor was found from her mesenteric lymph nodes and cerebrospinal fluid at autopsy. A lumbo-peritoneal shunt might be considered for meningeal carcinomatosis refractory to gefitinib treatment without an emergence of a T790M mutation.
Anticancer research 08/2009; 29(7):2759-60. · 1.73 Impact Factor
-
Kadoaki Ohashi,
Nagio Takigawa,
Masahiro Osawa,
Eiki Ichihara,
Hiromasa Takeda, Toshio Kubo,
Seiki Hirano,
Tadashi Yoshino,
Minoru Takata,
Mitsune Tanimoto,
Katsuyuki Kiura
[show abstract]
[hide abstract]
ABSTRACT: Twenty-five percent of all lung cancer cases are not attributable to smoking. Epidermal growth factor receptor (EGFR) mutations, which are involved in approximately 50% of nonsmoker lung cancer, are positively correlated with responsiveness to gefitinib, and inversely correlated with smoking history. Activating EGFR mutations play a critical role in the carcinogenesis of nonsmoking-related lung cancer. To investigate the chemopreventive effects of gefitinib on nonsmoking-related lung cancer, we generated transgenic mice expressing EGFR L858R in type II pneumocytes constitutively using the surfactant protein-C promoter. The transgenic mice invariably developed atypical adenomatous hyperplasia at age 4 weeks and multifocal adenocarcinoma of varying sizes at age 7 weeks. Notably, the expression levels of phosphorylated and total ErbB2, ErbB3, and thyroid transcription factor-1 were elevated in the transgenic mice compared with wild-type controls at age 3 weeks. Administration of gefitinib to 3-week-old transgenic mice for 1 week before carcinogenesis reduced the amount of phosphorylated EGFR in the lungs of the mice to the baseline level. Gefitinib (5 mg/kg/d; n = 5, 5, and 15) or vehicle (n = 5, 5, and 15) was administered to transgenic mice from age 3 to 8, 13, and 18 weeks, respectively. The numbers of lung tumors in the control and gefitinib-treated groups were 1.75, 5.8, 10.2, and 0 (P < 0.05), respectively. No fatal toxic events occurred in either group, and gefitinib inhibited tumorigenesis completely in this mouse model. These results suggest the utility of molecular targeted chemoprevention against nonsmoking-related lung cancer.
Cancer Research 08/2009; 69(17):7088-95. · 7.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A 47-year-old man who suffered from fever and dry cough visited a local clinic. His symptoms temporarily improved with oral administration of ciprofloxacin, however, he was admitted to our hospital because of exacerbation. IgM antibody for Mycoplasma pneumoniae was positive and IgM antibody titer for Chlamydophila pneumoniae showed a high value of 7.12 index. Thus, coinfection was diagnosed. The findings of chest X-ray and computed tomography were compatible with atypical pneumonia. Clarithromycin improved his condition, and 10 weeks later, antibody values for Mycoplasma pneumoniae by the particle agglutination test decreased from 10,240 times to 640 times and those by the complement-fixation test also decreased from 1024 times to 256 times. The IgM antibody for Chlamydophila pnetumoniae decreased to 0.13. This is the first case developing coinfection with Mycoplasma pneumoniae and Chlamydophila pneumoniae in a middle-aged patient to date.
Nihon Kokyūki Gakkai zasshi = the journal of the Japanese Respiratory Society. 11/2007; 45(10):808-11.
