A randomized, postremission comparison of four courses of standard-dose consolidation therapy without maintenance therapy versus three courses of standard-dose consolidation with maintenance therapy in adults with acute myeloid leukemia: the Japan Adult Leukemia Study Group AML 97 Study

BACKGROUND: A major concern in the treatment of patients with acute myeloid leukemia (AML) is how to prevent disease recurrences. Although intensive consolidation therapy has proven useful, the effectiveness of maintenance therapy remains controversial. METHODS: Seven hundred eighty-nine patients ages 15-64 (median: 45 yrs) with de novo AML received induction therapy, which consisted of cytosine arabinoside (at a dose of 100 mg/m(2) on Days 1-7) and idarubicin (at a dose of 12 mg/m(2) on Days 1-3). The patients who achieved complete remission (CR) were then randomized into groups that received either four courses of standard-dose consolidation therapy without maintenance (Arm A) or three courses of standard-dose consolidation and six courses of maintenance therapy (Arm B). RESULTS: In total, 78.7% of patients achieved CR. The 5-year overall survival (OS) rate for the 789 eligible patients was 46.9%, and the disease-free survival (DFS) rate for the 621 patients who achieved CR was 32.9%. The 5-year OS rate for Arm A was 52.4%, and 58.4% for Arm B (P = 0.599). The 5-year DFS rate for the patients who achieved CR was 35.8% in Arm A and 30.4% in Arm B (P = 0.543). In analyzing the data according to the risk groups, no statistical difference was observed either in the 5-year OS rate or in the 5-year DFS rate between the 2 arms. CONCLUSIONS: In the current study, the Japan Adult Leukemia Study Group's conventional postremission therapy (three courses of standard-dose consolidation and six courses of maintenance therapy) was replaced successfully by a shorter duration of four courses of standard-dose consolidation therapy without the need for additional maintenance therapy.     

Targeted therapy against Bcl-2-related proteins in breast cancer cells

Introduction

Bcl-2 and Bcl-xL confer resistance to apoptosis, thereby reducing the effectiveness of chemotherapy. We examined the relationship between the expression of Bcl-2 and Bcl-xL and chemosensitivity of breast cancer cells, with the aim of developing specific targeted therapy.

Methods

Four human breast cancer cell lines were examined, and the effects of antisense (AS) Bcl-2 and AS Bcl-xL phosphorothioate oligodeoxynucleotides (ODNs) on chemosensitivity were tested in vitro and in vivo. Chemosensitivity was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay, and the antitumor effect was assessed in vivo by the success of xenograft transplantation into athymic mice.

Results

Treatment with AS Bcl-2 and Bcl-xL ODNs resulted in a sequence-specific decrease in protein expression, compared with controls. Treatment of BT-474, ZR-75-1, and MDA-MB-231 cells with AS Bcl-2 increased chemosensitivity to doxorubicin (DOX), mitomycin C (MMC), paclitaxel (TXL), and docetaxel (TXT). Transfection of the Bcl-2 gene into MDA-MB-453 cells decreased sensitivity to DOX and MMC. Treatment of MDA-MB-231, BT-474, and ZR-75-1 cells with AS Bcl-xL increased chemosensitivity to DOX, MMC and taxanes to a smaller extent than AS Bcl-2. This occurred in the setting of increased Bax and cleaved poly(ADP-ribose) polymerase, as well as decreased Bcl-2 and pAkt. AS Bcl-2 ODNs induced splenomegaly in association with increased serum IL-12, which was attenuated by methylation of the CpG motifs of AS Bcl-2; however, methylated CpG failed to negate the increased antitumor effect of AS Bcl-2. Bcl-2 and Bcl-xL, to a smaller extent, are major determinants of chemosensitivity in breast cancer cells.

Conclusion

Targeted therapy against Bcl-2 protein with the use of AS ODNs might enhance the effects of chemotherapy in patients with breast cancer.     

Rationale for sequential tamoxifen and anticancer drugs in adjuvant setting for patients with node- and receptor-positive breast cancer

Since the survival benefit of tamoxifen (TAM) combined with anticancer drugs in treating node- and receptor-positive breast cancer is small, appropriate treatment schedules and the rationale for the combination remains unclear. We examined the effect of estradiol (E2) on sensitivity to anticancer drugs to clarify the survival benefit of tamoxifen combined with anticancer drugs. We used the MTT assay to assess the effect of E2 on sensitivity to anticancer drugs in the E2 receptor-positive and -negative breast cancer cell lines, MCF-7 and MDA-MB-231, respectively. We assessed the expression of apoptosis-related proteins by Western blotting, and evaluated apoptosis using the TUNEL method. Serum levels of E2 were measured using an enzyme-labeled radioimmunoassay in patients with premenopausal breast cancer before and during treatment with tamoxifen. Estrogen administration decreased sensitivity in MCF-7 cells to the anticancer drugs, adriamycin (ADM), mitomycin C (MMC), and paclitaxel (TXL), evaluated as increases in the IC50 values for ADM (4.1-fold), MMC (1.9-fold) and TXL (13.0-fold), compared with those of each drug alone. Estradiol in MDA-MB-231 cells similarly increased the IC50 values for ADM (9.5-fold), MMC (15.6-fold), and TXL (2.4-fold). The decreased sensitivity to these anticancer drugs was associated with the attenuation of apoptosis. Estrogen dose-dependently increased the expression of Bcl-2 protein in MCF-7, but not in MDA-MB-231 cells, and suppressed the expression of Bax and cytochrome c induced by anticancer drugs in association with decreased apoptosis compared with the effect of each drug alone. Phosphorylation of the Bcl-2 protein induced by TXL was decreased in the presence of E2 in MCF-7 cells. Serum levels of E2 were increased in 5 patients without amenorrhea and in 1 patient with amenorrhea after treatment with TAM alone in adjuvant therapy, compared with levels before treatment. Estradiol decreased sensitivity to ADM, MMC, and TXL in MCF-7 and MDA-MB-231 breast cancer cells, and this was associated in part with an increase in the amount of Bcl-2 protein, and decreases in levels of Bax and cytochrome c leading to apoptosis. These results suggest that therapy with TAM and anticancer drugs should be sequentially scheduled with anticancer drugs followed by TAM in an adjuvant setting to treat patients with breast cancer for a potentially improved survival benefit.     

Caspase-dependent and -independent cell death pathways after DNA damage (Review)

Apoptosis is known to be an important phenomenon in exerting antitumor response to cancer therapy, which is regulated by Bcl-2 family proteins through mitochondrial permeability transition (MPT). Insertion by the activated Bax/Bak in response to DNA damage induces mitochondrial membrane permeabilization (MMP) via an anion channel, VDAC in mitochondrial outer membrane that plays a crucial role in releasing small molecules such as cytochrome c, Smac/DIABLO, Omi/HtrA2, AIF, and endonuclease G leading to cell death. The released small molecules are involved in caspase-dependent and -independent cell death pathway that is inhibited by Bcl-2/xL. Despite the fact that the pancaspase inhibitor, zVAD-fmk inhibited the caspase cascade, cell death mediated by caspase-independent pathway was not blocked. Similarly, although etoposide induced-apoptosis was inhibited in Bax(-/-)/Bak(-/-)mouse embryonic fibroblasts, autophagy was not inhibited, which was regulated by Bcl-xL. It appears that the cross-talk between caspase-dependent and -independent apoptotic cell death including autophagic cell death that was mediated by MPT affects overall tumor response to anticancer treatment. In this review, to assist a comprehensive understanding of MPT-mediated cell death pathway for exploring appropriate targets in cancer therapy, role of the caspase-dependent and -independent cell death pathway in the interaction of these pathways is discussed.     

Autopsy case of CD4/CD8 cutaneous T-cell lymphoma presenting disseminated pagetoid reticulosis with aggressive granulomatous invasion to the lungs and pancreas

Pagetoid reticulosis is a rare cutaneous T-cell lymphoma with striking epidermotropism similar to that present in Paget's disease. There are two forms of pagetoid reticulosis: localized and disseminated. Reported herein is an autopsy case of disseminated pagetoid reticulosis with CD4(-)/CD8(-) phenotype T cells and massive invasion of the lungs and pancreas. The abnormal cells in the epidermis expressed a protein derived from a rearranged T-cell receptor beta gene, and this feature was used to confirm the monoclonality of these cells by polymerase chain reaction. At present, the World Health Organization (WHO) classification system considers pagetoid reticulosis to be an indolent form of primary cutaneous T-cell lymphoma and a variant of mycosis fungoides/Sezary syndrome with prominent epidermotropism. Some differences have been observed between pagetoid reticulosis and mycosis fungoides in terms of clinical course, tumor cell phenotype, and genetic findings; and these differences are highlighted in the present case. The relation between disseminated pagetoid reticulosis, CD4(-)/CD8(-) cutaneous T-cell lymphoma, and gammadelta T-cell lymphoma, including whether pagetoid reticulosis is a variant of mycosis fungoides, remains unclear.     

Heavily melanotic perivascular epithelioid clear cell tumor of the kidney

A black-colored and well-circumscribed renal tumor in a 71-year-old woman is reported. The tumor was unique in that it was rich in vasculature and exclusively composed of perivascular epithelioid clear cells. Morphological features were reminiscent of conventional renal cell carcinoma (RCC). However, immunohistochemical examinations showed that the tumor cells did not express any epithelial markers, but diffusely and intensely expressed a melanocytic marker, gp-100/HMB-45. Another striking feature of the tumor was a large amount of cytoplasmic pigment that made the tumor wholly black. The pigment was not stained with Berlin-blue, completely bleached with potassium permanganate, and stained with Fontana-Masson staining, which suggests that the pigment was melanin. Morphological features and immunohistochemical findings indicated that the present tumor was an extreme example of a perivascular epithelioid clear cell tumor with a large amount of melanin, which has not been previously reported. One should be aware of the pure form of perivascular epithelioid clear cell tumor of the kidney because it is sometimes very difficult to differentiate this tumor from conventional RCC. Immunohistochemical examinations and the presence of cytoplasmic melanin can help the differentiation.     

Distribution of the small molecular weight GTP-binding proteins Rac1, Cdc42, RhoA and RhoB in the developing chick retina

Immunohistochemistry was used to determine the distribution of Rac1, Cdc42, RhoA and RhoB GTPases during development of the chick retina. All proteins appear as early as embryonic day 5 (E5) in cells of the vitreal margin, E7–8 in cells of the inner third of the inner nuclear layer and E9–10 in photoreceptors. From E10 until hatching, RhoA, Rac1 and Cdc42 were seen in perikarya and/or processes of amacrine, ganglion cells, and photoreceptors. Rho proteins were also observed in retinal Müller cells, with different distributions. RhoB showed a transient expression, being severely down regulated after E18. The distribution pattern of Rho proteins during the development of the chick retina suggests a concerted role in the differentiation of specific cell types, and probably during synaptogenesis.     

A polymorphic CA repeat sequence at the human calcitonin locus

A polymorphic dinucleotide (CA) repeat sequence was isolated from a genomic clone containing the human calcitonin gene at 11p15.2–p15.1. This polymorphism will be a useful marker in the genetic study of disorders affecting calcium metabolism including hyperparathyroidism, hypoparathyroidism, and osteoporosis. Received: November 10, 1997 / Accepted: December 5, 1997     

Reduction of interleukin-2-receptor expression on retroplacental blood lymphocytes in human pregnancy

Retroplacental blood lymphocytes (RPL) in human pregnancy were studied for proliferative response induced by recombinant interleukin-2 (rIL-2) and anti-Tac positive cells before and after PHA stimulation for 24 hr and compared with peripheral blood lymphocytes (PBL) of the same donor. Proliferation of RPL induced by IL-2 was significantly lower than that of PBL in all of six cases. In addition, flow cytometry analysis of IL-2 receptors (IL-2R) revealed that IL-2R expression of RPL after stimulation with PHA for 24 hr was significantly less than that of PBL in three of four cases and that RPL showed significantly fewer IL-2R than PBL even at resting state in one case. These results suggest that RPL seem likely to be composed of reduced numbers of lymphocytes bearing IL-2R of non-Tac protein and to have impaired capacity for the acquisition of high-affinity receptors for IL-2.     

Effects of granisetron, a 5-HT3 receptor antagonist, on 5-hydroxytryptamine (5-HT) release from the isolated ileum in a delayed-emesis rat model

We examined the effects of granisetron, a 5-HT3-receptor antagonist, on the release of serotonin (5-hydroxytryptamine, 5-HT) from the isolated ileum and on histopathological changes of the intestine in a delayed-emesis rat model. The rats were studied 72 hours after receiving an intraperitoneal (i.p.) dose of cisplatin (5 mg/kg). The 5-HT content in the isolated ileum 72 hours after administration was significantly higher in the cisplatin group (26.0 +/- 3.0 ng/mg protein, p < 0.001) than in the non-drug control group (9.6 +/- 0.6 ng/mg protein). The increase in 5-HT content in the cisplatin group was significantly inhibited in rats pretreated with granisetron (17.5 +/- 2.2 ng/mg protein, p < 0.05). The release of 5-HT from the isolated ileum was significantly greater in the cisplatin group (11,963.0 +/- 2,104.6 ng x hr/g tissue, p < 0.01) than in the non-drug control group (2,861.0 +/- 210.7 ng x hr/g tissue). The increased 5-HT release from the isolated ileum in the cisplatin group was significantly inhibited in rats pretreated with granisetron (3,359.8 +/- 494.3 ng x hr/g tissue, p < 0.01). Disarrangement of intestinal villi, luminal dilatation of crypts and decreased numbers of goblet cells were observed in the cisplatin group. The group pretreated with granisetron showed mild macroscopic and histopathological changes, but no significant weight loss. The histopathological changes of the intestinal mucosa were apparently associated with the release of 5-HT. Our results suggest that 5-HT release from the enterochromaffin cells, accompanied by histopathological changes of the intestinal mucosa, is involved in the onset of delayed emesis after administration of cisplatin. These findings suggest that treatment with granisetron before the administration of anticancer drugs may prevent delayed emesis and intestinal disturbances associated with anticancer drugs.