Takeshi Kitazaki

Reversal of breast cancer resistance protein (BCRP/ABCG2)-mediated drug resistance by novobiocin, a coumermycin antibiotic

Breast cancer resistance protein (BCRP/ABCG2) of an ATP‐binding cassette half‐transporter confers resistance against mitoxantrone and camptothecin derivatives of topotecan and irinotecan. Novobiocin, a coumermycin antibiotic, is known to enhance anticancer drug sensitivity of cancer cells in vitro and in vivo, the mechanism of which remains undetermined. Here we focused on drug efflux pump and examined whether novobiocin reversed drug resistance in multidrug‐resistant cells highly expressing BCRP. To explore the reversal mechanisms, intracellular drug accumulation was measured by flow cytometry, and a topotecan transport study using plasma membrane vesicles was performed. We used PC‐6/SN2‐5H2 small cell lung cancer and MCF‐7/MX breast cancer cells selected with SN‐38 of the active irinotecan metabolite and mitoxantrone, respectively, and the BCRP cDNA transfectant MCF‐7/clone 8 cells. These cells expressed high levels of BCRP mRNA but not other known transporters. Compared to the parental PC‐6 cells, PC‐6/SN2‐5H2 cells were 141‐, 173‐ and 57.2‐fold resistant to topotecan, SN‐38 and mitoxantrone, respectively. Novobiocin at 60 μM decreased the degree of the above resistance by approximately 26‐fold in PC‐6/SN2‐5H2 cells, and similarly reversed resistance in MCF‐7/MX, MCF‐7/clone 8 and un‐selected NCI‐H460 cells highly expressing BCRP. Furthermore, novobiocin increased the intracellular topotecan accumulation in these cells and inhibited the topotecan transport into the membrane vesicles of PC‐6/SN2‐5H2 cells. No effects of novobiocin in these assay were observed in the parental PC‐6 and MCF‐7 cells. The kinetic parameters in the transport study indicated that novobiocin was a inhibitor for BCRP, resulting in competitive inhibition of BCRP‐mediated topotecan transport. These findings suggest that novobiocin effectively overcomes BCRP‐mediated drug resistance at acceptable concentrations.

Different effects of telithromycin on MUC5AC production induced by human neutrophil peptide-1 or lipopolysaccharide in NCI-H292 cells compared with azithromycin and clarithromycin

OBJECTIVES Mucus hypersecretion is a prominent feature in patients with chronic respiratory tract infections such as cystic fibrosis and diffuse panbronchiolitis, and the clinical effectiveness of macrolide antibiotics has been reported in these patients. Because human neutrophil peptide-1 (HNP-1), an antimicrobial peptide in neutrophils, exists in high concentrations in the airway fluid of these patients, we examined the direct effect of HNP-1 on MUC5AC mucin production using NCI-H292 cells. The effects of macrolide antibiotics on the response were also examined. METHODS MUC5AC synthesis was assayed using RT-PCR and ELISA. Phosphorylation of ERK1/2 was determined by western blotting. RESULTS Stimulation with HNP-1 or lipopolysaccharide (LPS) derived from Pseudomonas aeruginosa increases the production of MUC5AC mRNA and protein, and an additive effect was found upon co-stimulation with both HNP-1 and LPS. Azithromycin and clarithromycin had inhibitory effects on overproduction of MUC5AC induced by HNP-1 or LPS stimulation. Telithromycin also had an inhibitory effect on MUC5AC production induced by LPS, but not on production by HNP-1. Phosphorylation of ERK1/2 was induced by HNP-1 or LPS stimulation, and azithromycin, clarithromycin and telithromycin had inhibitory effects on ERK1/2 phosphorylation induced by LPS, but not by HNP-1. CONCLUSIONS These findings suggest that neutrophil-derived defensins as bacterial components contribute to excessive mucus production in patients with respiratory tract infections, and that macrolide and ketolide antibiotics directly inhibit these actions by interfering with intracellular signal transduction. However, the mechanism of telithromycin inhibition of MUC5AC synthesis may differ from the response induced by azithromycin and clarithromycin.

Methylation status of breast cancer resistance protein detected by methylation-specific polymerase chain reaction analysis is correlated inversely with its expression in drug-resistant lung cancer cells

Breast cancer resistance protein (BCRP) functions as a drug efflux transporter that mediates drug resistance. Topoisomerase I inhibitors, including 7‐ethyl‐10‐hydroxycamptothecin (SN‐38), are substrates effluxed by BCRP. However, it remains unclear whether the overexpression of BCRP induces drug resistance during chemotherapy. The objectives of the current study were to examine a correlation of altered promoter methylation of BCRP with BCRP expression and to investigate the correlation between methylation status according to methylation‐specific polymerase chain reaction (MSP) analysis and BCRP expression levels in several small cell and nonsmall cell lung cancer cells.

Spontaneous remission of a non-small cell lung cancer possibly caused by anti-NY-ESO-1 immunity.

Spontaneous remission of malignant tumors is rare and the biological mechanism of such remission has not been addressed. We report the case of a 71-year-old Japanese patient with non-small cell lung cancer with a right hilar tumor and pleural dissemination that spontaneously regressed. NY-ESO-1 is a cancer/testis antigen that can elicit specific immune responses in patients with cancer. Strong anti-NY-ESO-1 immunity was detected in this patient. His tumor cells expressed NY-ESO-1 and MHC class I molecules. Anti-NY-ESO-1 immunity might have contributed to spontaneous remission in this patient.

Prospective study of the UGT1A1*27 gene polymorphism during irinotecan therapy in patients with lung cancer: Results of Lung Oncology Group in Kyusyu (LOGIK1004B)

Uridine 5′‐diphospho‐glucuronosyltransferase 1A1 (UGT1A1*27) is known to impair the effect of UGT in basic research; however, little clinical investigation has been conducted. To evaluate the effect of the UGT1A1*27 polymorphism in irinotecan therapy, we conducted a prospective study.

Chronic necrotizing pulmonary aspergillosis following cryptococcal infection of the lung.

A 64-y-old male with steroid-induced diabetes mellitus was admitted to our hospital because of a nodular shadow found by chest radiography. Pathological examination revealed pulmonary cryptococcosis, and he was positive for serum Cryptococcus antigen. After oral treatment with fluconazole, he experienced clinical and radiographic improvement, but during ensuing observation without antifungal treatment his respiratory symptoms gradually worsened. Chest radiography showed progressive infiltration around the cavity, and Aspergillus mold was isolated by transbronchial lung biopsy from the lesion where previous cryptococcal infection was present. In addition, serum antibodies to Aspergillus antigens were demonstrated by immunodiffusion. Thus, pulmonary aspergillosis was found to complicate a case of pulmonary cryptococcal infection.

Phase I study of irinotecan for previously treated lung cancer patients with the UGT1A1*28 or *6 polymorphism: Results of the Lung Oncology Group in Kyushu (LOGIK1004A)

Various polymorphisms have been detected in the UDP‐glucuronosyltransferase 1A ( UGT1A ) gene, and UGT1A1 *28 and UGT1A1 *6 have important effects on the pharmacokinetics of irinotecan and the risk of severe toxicities during irinotecan therapy. This study was conducted to determine the maximum tolerated dose (MTD) of irinotecan chemotherapy according to the UGT1A1 genotype in previously treated lung cancer patients with the UGT1A1 *28 or UGT1A1 *6 polymorphism.

Adverse renal effects of anaplastic lymphoma kinase inhibitors and the response to alectinib of an ALK+ lung cancer patient with renal dysfunction

A 62-year-old female patient with renal dysfunction and pulmonary adenocarcinoma developed postoperative recurrence and received carboplatin/pemetrexed and maintenance pemetrexed. As an anaplastic lymphoma kinase (ALK) gene translocation was identified, the therapy was changed to crizotinib. However, the patient’s blood creatinine level increased, and her physical status worsened. Alectinib also induced exacerbation of renal dysfunction but was controlled by dose reduction of 140 mg twice daily for 2 weeks treatment and 2 weeks break were repeated, and exhibited a partial response for 16 months. Here, we describe the case in which alectinib treatment had beneficial clinical effects on ALK-positive lung adenocarcinoma, which controlled the adverse renal effects by dose reduction and drug breaks.

Changes in Immunohistochemical Protein Levels in Anaplastic Lymphoma Kinase-positive Lung Adenocarcinoma Possibly due to Chemo-radiotherapy.

To detect the anaplastic lymphoma kinase (ALK) fusion gene in non-small cell lung cancer, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the standard methods. However, there are discrepancies between them. We herein report a 40-year-old woman with ALK fusion-positive adenocarcinoma that changed from positive to negative in IHC due to chemo-radiotherapy. Recurrence of the disease restored the IHC expression, whereas FISH was positive throughout the entire clinical course. Our experience suggests that we should therefore carefully evaluate samples after chemotherapy and radiotherapy.

Serum progastrin-releasing peptide levels followed by whole-body positron emission tomography detects early recurrence of small-cell lung cancer

Abstract:  A 65‐year‐old male smoker with severe COPD was diagnosed with limited‐stage small‐cell lung cancer. After receiving cisplatin/irinotecan, serum progastrin‐releasing peptide (ProGRP) levels decreased to within the reference values and the lesions were markedly reduced in size. A whole‐body 18F‐fluorodeoxyglucose PET (FDG‐PET) scan confirmed complete remission. During follow up, serum ProGRP levels increased, and a whole‐body FDG‐PET scan detected recurrence at the hilar lymph node that had been negative on CT. Complete remission was again achieved with second‐line chemotherapy (cisplatin/etoposide) and local irradiation to the hilar lymph node. Monitoring serum ProGRP levels, followed by whole‐body FDG‐PET when indicated, may improve the clinical management of patients with small‐cell lung cancer after initial complete remission.