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Background There is increasing evidence that immunotherapy with nivolumab, an anti‐programmed death 1 monoclonal antibody, is effective in the treatment of recurrent or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). However, the predictive role of hematological inflammatory markers such as neutrophil‐to‐lymphocyte ratio (NLR) and the modified Glasgow prognostic score (mGPS) in patients with R/M SCCHN treated with nivolumab remains unclear. Methods We conducted a multi‐institutional cohort study to evaluate the impact of pretreatment NLR and mGPS on overall survival (OS) and progression‐free survival (PFS) in patients with R/M SCCHN treated with nivolumab in Japan. From 2012 to 2013, 102 patients were eligible, of whom 88 were finally included in the analysis. mGPS was calculated as follows: mGPS of 0, C‐reactive protein (CRP) ≤1.0 mg/dL; 1, CRP > 1.0 mg/dL; and 2, CRP > 1.0 mg/dL and albumin, Immunotherapy with nivolumab is effective in the treatment of R/M SCCHN. However, reliable predictive markers have remained unclear. Higher pre‐treatment NLR and mGPS were significantly associated with worse survival, suggesting that these markers may be predictors of treatment with nivolumab.

Heme plays an important biomodulating role in various cell functions. In this study, we examined the effects of hemin on cellular sensitivity to imatinib and other anti-leukemia reagents. Hemin treatment of human BCR/ABL-positive KCL22 leukemia cells increased IC(50) values of imatinib, that is, the drug resistance, in a dose-dependent manner without any change in the BCR/ABL kinase activity. Imatinib-induced apoptosis was also suppressed by hemin treatment in KCL22 cells. Hemin treatment increased the activity of gamma-glutamylcysteine synthetase (gamma-GCS) light subunit gene promoter, which contains a Maf recognition element (MARE). Protein levels of gamma-GCS and heme oxygenase-1 (HO-1), two MARE-containing genes, were also increased after hemin treatment. Knockdown of Nrf2 expression by RNA interference largely abolished the effect of hemin on imatinib-treated cells, suggesting that Nrf2 recognition of MARE is essential for the hemin-mediated protective effect. Similar to hemin, treatment of cells with delta-aminolevulinic acid (delta-ALA), the obligatory heme precursor, also increased IC(50) values of imatinib. In contrast, inhibition of cellular heme synthesis by succinylacetone increased the sensitivity of cells to imatinib in two imatinib-resistant cell lines, KCL22/SR and KU812/SR. Hemin treatment also decreased the sensitivity of cells to four anthracyclins, daunorubicin, idarubicin, doxorubicin, and mitoxantrone, in BCR/ABL-negative leukemia U937 and THP-1 cells, as well as in KCL22 cells. These findings thus indicate that cellular heme level plays an important role in determining the sensitivity of cells to imatinib and certain other anti-leukemia drugs and that the effect of heme may be mediated via its ability to upregulate Nrf2 activity.

Recent study has shown that nuclear glutathione S-transferase (GST) pi accumulates in cancer cells resistant to doxorubicin hydrochloride (DOX) and may function to prevent nuclear DNA damage caused by DOX (Goto et al., FASEB J., 15, 2702 - 2714 (2001)). It is not clear if the amount of nuclear GSTpi increases in response to other anti-cancer drugs and if so, what is the physiological significance of the nuclear transfer of GSTpi in the acquisition of drug-resistance in cancer cells. In the present study, we employed three cancer cell lines, HCT8 human colonic cancer cells, A549 human lung adenocarcinoma cells, and T98G human glioblastoma cells. We estimated the nuclear transfer of GSTpi induced by the anti-cancer drugs cisplatin (CDDP), irinotecan hydrochloride (CPT-11), etoposide (VP-16) and 5-fluorouracil (5-FU). It was found that: (1) Nuclear GSTpi accumulated in these cancer cells in response to CDDP, DOX, CPT-11, VP-16 and 5-FU. (2) An inhibitor of the nuclear transport of GSTpi, edible mushroom lectin (Agaricus bisporus lectin, ABL), increased the sensitivity of the cancer cells to DOX and CDDP, and partially to CPT-11. Treatment with ABL had no apparent effect on the cytotoxicity of VP-16 and 5-FU. These results suggest that inhibitors of the nuclear transfer of GSTpi have practical value in producing an increase of sensitivity to DOX, CDDP and CPT-11.

Glutathione S-transferase (GST) functions in xenobiotic biotransformation and drug metabolism. Increased expression of GSTpi, an isozyme of GST, has been found in cancer cells resistant to doxorubicin hydrochloride (DOX) or cis-diamminedichloroplatinum (II) (CDDP), and this increase was believed to be correlated with drug resistance of cancer cells. GST is mainly expressed in the cytoplasm; GSTpi in the nucleus has been reported in cancer cells, but the meaning of this result is not known. Here, we studied changes in the amount of nuclear GSTpi after exposure of cancer cells to anticancer drugs, and role of the nuclear GSTpi in drug resistance. We found nuclear GSTpi in cancer cells resistant to DOX, and the amount of nuclear GSTpi was enhanced by treatment of the cancer cells with DOX or CDDP. We also found that a mushroom lectin, an inhibitor of nuclear transport, inhibited the nuclear transfer of GSTpi, suggesting the existence of a specific transport system for the nuclear transfer of GSTpi. Nuclear GSTpi protected DNA against damage by anticancer drugs. These results suggest a possible role of GSTpi in the acquisition of resistance to anticancer drugs by cancer cells.

The significance of glutathione S-conjugate in the regulation of glutathione synthesis was studied using human erythrocyte gamma-glutamylcysteine synthetase. Feedback inhibition of the enzyme by reduced glutathione was released by the addition of the glutathione S-conjugate (S-2,4-dinitrophenyl glutathione). A half-maximal effect of glutathione S-conjugate on gamma-glutamylcysteine synthetase activity was obtained at approximately 1 microM; 50 microM glutathione S-conjugate in the presence of 10 mM glutathione actually increased the enzyme activity twofold above uninhibited levels. Glutathione S-conjugate had no effect on the enzyme activity in the absence of glutathione. When erythrocytes were exposed to the electrophile 1-chloro-2,4-dinitrobenzene, which forms a glutathione S-conjugate by the catalytic reaction of glutathione S-transferase, the level of glutathione synthesis increased. These data suggest that glutathione S-conjugate plays a role in stimulating the synthesis of glutathione.