Immunohistochemical Ki67 labeling index has similar proliferation predictive power to various gene signatures in breast cancer.

The objective of this study was to examine the association between the immunohistochemical Ki67 labeling index (IHC Ki67), Ki67 mRNA expression level, and first-generation gene signatures in a cohort of breast cancer patients. We assessed associations between IHC Ki67 and first-generation gene signatures in a panel of 39 tumor samples, using an oligonucleotide microarray. Gene expression analyses included Ki67 alone (MKi67), 21-gene signature, mitosis kinome score signature, and genomic grade index. Correlation coefficients were calculated by Spearman's rank correlation test. In all cases, IHC Ki67, MKi67, and three genetic markers were highly correlated (ρ, 0.71-0.97). Estrogen receptor (ER)-positive cases showed strong correlations between IHC Ki67 and other signatures (ρ, 0.79-0.83). The ER-negative cases showed slightly lower correlations (ρ, 0.58-0.73). In ER-positive cases, the low IHC Ki67 group showed significantly longer relapse-free survival than the high IHC Ki67 group (P = 0.007). This difference was confirmed by multivariate analysis. Our data indicate that IHC Ki67 shows similar predictive power for proliferation in ER-positive cancers as genomic markers. Further study of IHC Ki67 is needed to define prognostic factors and predictive factors for chemotherapy using central laboratory assessment.

Continuous inhibition of epidermal growth factor receptor phosphorylation by erlotinib enhances antitumor activity of chemotherapy in erlotinib-resistant tumor xenografts.

Erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor, has been shown to have benefits for non-small cell lung cancer and pancreatic cancer patients; however, almost all patients develop progressive disease during the therapy. On the other hand, it has been reported that a tumor continues to express epidermal growth factor receptor even after developing progressive disease. To demonstrate the clinical relevance of erlotinib treatment after progressive disease, we investigated whether continuous administration of erlotinib in combination with chemotherapy has a useful effect on progressive disease development during erlotinib treatment. For this purpose, we examined the antitumor effect of a combination therapy of a chemotherapeutic agent with erlotinib using two types of erlotinib-resistant tumor xenograft models: a non-small cell lung cancer model, in which EBC-1, H1975 and HCC827TR3 tumors were implanted, and an HPAC pancreatic cancer cell xenograft which generates erlotinib-resistant tumors in vivo. As a result, the combination therapy showed a significantly higher antitumor activity compared with chemomonotherapy in all xenograft models except the H1975 xenografts. Furthermore, erlotinib alone suppressed the phosphorylation of epidermal growth factor receptor in HPAC tumors and the two non-small cell lung cancer cell lines other than H1975. Therefore, combination therapy which uses erlotinib can be considered effective if epidermal growth factor receptor phosphorylation is inhibited by erlotinib, even in erlotinib-resistant tumor xenograft models. Our results suggest that the continuous inhibition of epidermal growth factor receptor phosphorylation by erlotinib after progressive disease enhances the antitumor activity of chemotherapy.

Schedule-dependent antitumor activity of the combination with erlotinib and docetaxel in human non-small cell lung cancer cells with EGFR mutation, KRAS mutation or both wild-type EGFR and KRAS.

Erlotinib is used as a standard treatment for recurrent advanced non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutations in NSCLC have been shown to be a predictive factor of erlotinib, although the relationship between K-ras oncogene (KRAS) mutations and erlotinib resistance is controversial. Recently, in vitro sequence-dependent interactions of erlotinib and docetaxel have been studied on as a novel therapeutic approach against NSCLC. The purpose of the present study was to determine the optimum novel regimen of erlotinib and docetaxel against NSCLC cells which have EGFR mutation (HCC827 cells), KRAS mutation (A549 cells) or both wild-type (NCI-H292 cells). First, we analyzed the effects of in vitro combination for cell proliferation-inhibition using a combination index. In all cell lines, docetaxel followed by erlotinib treatment showed nearly additive effects. On the other hand, erlotinib followed by docetaxel treatment showed remarkable antagonistic interactions. Second, we examined the effect of combinations on the in vitro apoptosis induction. Erlotinib followed by docetaxel treatment reduced apoptosis induction compared with docetaxel alone; in contrast, docetaxel followed by erlotinib treatment had no inhibitory effects on docetaxel-induced apoptosis in any of the cell lines. Finally, an in vivo tumor growth inhibition test was performed using xenograft models. Docetaxel followed by erlotinib administration resulted in significant tumor growth inhibition compared with erlotinib or docetaxel monotherapy in all models. In conclusion, we demonstrated that docetaxel followed by erlotinib therapy was a potentially optimum regimen against NSCLC regardless of the mutation status of EGFR and KRAS.

[Microarray analysis of tumor xenograft model].

We carried out gene expression profiling of forty human tumor cells for research choice method of the most fitting anticancer drug, using unsupervised hierarchal clustering analysis. This clustering analysis is based on a tumor growth inhibition panel of nine antitumor drugs (MMC, CDDP, ACNU, CPT-11, CPA, FT-207, UFT, 5'-DFUR and ADM) for forty human cancers. These cancers(eleven stomach, seven colon, six breast, three pancreas, five lung, two esophageal carcinomas, one liver, one renal cell carcinoma, one uterus, two ovarian, and one melanoma) have been maintained by serial s. c. passages in nude mice of the same sex of donor patients. Nine antitumor drugs were divided into two groups, a 5-FU-related drug group (5'-DFUR, FT-207 and UFT) and another group. On the other hands, forty cells were clustered into four groups. By using GeneChip (Hu95Av2, Affymetrix), we investigated gene expression profiling of the matched tumor cells and selected specific genes in each group. Interestingly, a pathway analysis revealed that expressions of p53-related genes were up-regulated in the 5-FU-sensitive groups. This result suggested that chemosensitivity was predicted by gene expression profiling of tumor cells. We considered that microarray analysis would be a good tool for further tailor-made medications.

High expression of thymidine phosphorylase in basal-like breast cancers: Stromal expression in EGFR- and/or CK5/6-positive breast cancers.

Expression of the estrogen receptor (ER), the progesterone receptor (PgR) or the human epidermal growth factor receptor-2 (HER2) in tumors is a good prognostic marker for breast cancer patients. However, approximately 15-20% of breast cancer patients have triple-negative breast cancer (TNBC; negative for ER, PgR and HER2), and efficient therapeutic modalities for these patients are under investigation. We focused on thymidine phosphorylase (TP), an enzyme metabolizing 5'-DFUR, an intermediate of capecitabine, to 5-fluorouracil in order to investigate the application of well-known therapeutics for TNBC. Results of a gene expression analysis showed that TP expression in TNBC and basal-like breast cancer (BLBC) was higher than that of other subtypes. Immunohistochemically, the high expression of TP in TNBC and BLBC reflected expression in stromal but not tumor cells. Notably, a high TP expression was observed in the stromal cells of EGFR- and/or CK5/6-positive breast tumors. Our present results showing a high expression of TP in BLBC indicate that capecitabine-based chemotherapy would be of benefit for patients with TNBC.

Effect of erythropoietin on human tumor growth in xenograft models.

Recombinant human erythropoietin (rhEPO) has been used in the EU and the United States for the treatment of anemia in cancer patients after myelosuppressive chemotherapy or radiotherapy. However, several conflicting results have been reported concerning the detrimental effect of rhEPO on survival benefit in cancer patients. In experimental studies, contradictory results were also reported in in vitro tumor cell proliferation studies and in vivo tumor growth studies using tumor cells expressing EPO-receptor (EPO-R). Therefore, we tried to clarify the effect of epoetin ß, a product of rhEPO, on tumor growth in xenograft models using five EPO-R-positive human cancer cell lines, namely the MCF7 breast, 786-O renal, SCH gastric, A549 lung and SK-OV-3 ovarian cancer cell lines. Epoetin ß was administered once a week for 3 weeks at doses of 1,000, 3,000 and 10,000 IU/kg in accordance with the clinical administration schedule and dosages. As a result, no enhancement of tumor growth from the administration of epoetin ß was observed in any of the xenograft models throughout the experiment duration. The effect of epoetin ß on the antitumor activity of bevacizumab, an anti-angiogenic agent, was additionally examined using A549 and MCF7 xenograft models, since rhEPO reportedly stimulates tumor neovascularization. Epoetin ß showed no significant effect on the antitumor activity of bevacizumab in either xenograft model. These findings suggest that epoetin ß is not involved in in vivo tumor growth promotion.

Preclinical study of prolonged administration of trastuzumab as combination therapy after disease progression during trastuzumab monotherapy.

PURPOSE: The clinical relevance of prolonged trastuzumab administration in combination therapy beyond progressive disease (PD) has been suggested. Here, we examined whether trastuzumab treatment is effective in combination after failing to show antitumor activity as monotherapy in HER2-positive human breast cancer xenograft models. METHODS: We established trastuzumab PD models with HER2-positive breast cancer xenograft models and compared the antitumor activity of trastuzumab in combination with a taxane versus monotherapy with a taxane in the models subsequent to tumor progression under trastuzumab monotherapy. RESULTS: We established trastuzumab PD model using the HER2-positive human breast cancer line MDA-MB-361 and KPL-4 in in vivo. In these models, trastuzumab at the same dose as the initial treatment showed no significant antitumor activity at 3 weeks after start of treatment. Re-inoculated tumor tissues showing PD regained sensitivity to trastuzumab. In the trastuzumab PD models, the HER2 status of the tumor tissues did not decrease. Also, the pAKT level continued to decrease, as with the initial treatment, and IGF-1R was not found to be up-regulated. Instead, differences were observed in the gene-expression profiles of the tumor tissues showing PD. Trastuzumab in combination with G-CSF, which is expected to enhance antibody-dependent cellular cytotoxicity (ADCC), showed significant antitumor activity, even though the single agents alone showed no antitumor activity in the PD model. In the MDA-MB-361 trastuzumab PD model, the combination of trastuzumab with paclitaxel showed significantly more potent antitumor activity compared with paclitaxel or docetaxel monotherapy. In the KPL-4 trastuzumab PD model as well, trastuzumab showed significant antitumor activity in combination with taxanes or capecitabine after PD had developed in response to trastuzumab monotherapy. CONCLUSION: We established in vivo trastuzumab PD models, in which trastuzumab monotherapy ceases to have antitumor activity during the treatment. The mechanisms of PD with trastuzumab are considered to involve both reversible changes in the gene expression profiles in tumor tissues and a decrease of ADCC activity in the host. Our present results demonstrated that trastuzumab showed antitumor activity in combination with taxanes or capecitabine even though it showed no antitumor activity as a monotherapy, suggesting a clinical relevance of treatment with trastuzumab as a combination therapy beyond PD.

Chemosensitivity-related genes of breast cancer detected by DNA microarray.

BACKGROUND: The feasibility of a preoperative docetaxel/5'-deoxy-5-fluorouridine (5'-DFUR) regimen for breast cancer patients was examined and the genes related to the response to it was investigated. PATIENTS AND METHODS: Women with advanced breast cancer were treated with docetaxel (60 mg/m2, day 1) and 5'-DFUR (800 mg/day, on days 1-14) q3 weeks by 4 cycles. Microarray analysis was carried out using preoperative core biopsy samples. Based on the mRNA expression levels, genes related to clinical and pathological responses were selected. RESULTS: The docetaxel/5'-DFUR regimen showed a 86% clinical response rate including 42% complete response, one pathological complete response and one ductal carcinoma in situ component. In microarray analysis, we identified 6 genes, including IGF-1, and derived a predictive formula with 67% accuracy. In addition, x2 analysis revealed a tendency for good response in ER-negative and Her2/neu-positive cases. CONCLUSION: Microarray analysis enabled us to predict the pathological response to docetaxel/5'-DFUR chemotherapy.

Capecitabine improves cancer cachexia and normalizes IL-6 and PTHrP levels in mouse cancer cachexia models.

PURPOSE: To clarify the potential of parathyroid hormone-related protein (PTHrP) and interleukin-6 (IL-6) as cachectic factors in a colon 26 model and the effects of capecitabine on cancer cachexia as determined by plasma levels of IL-6 and PTHrP and body weight loss. METHODS: From two colon 26 sublines-cancer cachectic clone20 and non-cachectic clone5 plasma levels of PTHrP protein and mRNA expression levels in tumor tissues were compared. An IL-6 neutralizing antibody, a PTHrP neutralizing antibody, and capecitabine were administered into mice bearing clone20 and their anticachectic effects evaluated. RESULTS: The plasma level of PTHrP protein in mice bearing clone20 was higher than that in mice bearing clone5. The expression level of PTHrP mRNA was 49-fold higher in tumor tissues of clone20 than of clone5, according to GeneChip analysis. PTHrP antibody as well as IL-6 antibody suppressed wasting of the body and gastrocnemius and adipose tissue weights. PTHrP antibody suppressed the induction of hypercalcemia but not hypoglycemia or elevation of IL-6, whereas IL-6 antibody suppressed the induction of hypoglycemia but not hypercalcemia or elevation of PTHrP. Capecitabine, a fluorinated pyrimidine anticancer agent, improved body wasting of mice bearing clone20 at a low dose with no reduction of tumor volume. Furthermore, capecitabine lowered the levels of PTHrP and IL-6 in plasma and suppressed hypoglycemia and hypercalcemia in this model. Capecitabine also showed anticachectic effects on cachexia in a cancer model induced by human cervical cancer cell line Y (also known as Yumoto). CONCLUSIONS: PTHrP and IL-6 were found to be factors in the development of cachexia in a colon 26 cancer model, and capecitabine improved cancer cachexia by suppressing the plasma levels of IL-6 and PTHrP in colon 26 and Y cachectic models.

Prediction of sensitivity of rectal cancer cells in response to preoperative radiotherapy by DNA microarray analysis of gene expression profiles.

Preoperative radiotherapy has been widely used to improve local control of disease and to improve survival in the treatment of rectal cancer. However, the response to radiotherapy differs among individual tumors. Our objective here was to identify a set of discriminating genes that can be used for characterization and prediction of response to radiotherapy in rectal cancer. Fifty-two rectal cancer patients who underwent preoperative radiotherapy were studied. Biopsy specimens were obtained from rectal cancer before preoperative radiotherapy. Response to radiotherapy was determined by histopathologic examination of surgically resected specimens and classified as responders or nonresponders. By determining gene expression profiles using human U95Av2 Gene Chip, we identified 33 novel discriminating genes of which the expression differed significantly between responders and nonresponders. Using this gene set, we were able to establish a new model to predict response to radiotherapy in rectal cancer with an accuracy of 82.4%. The list of discriminating genes included growth factor, apoptosis, cell proliferation, signal transduction, or cell adhesion-related genes. Among 33 discriminating genes, apoptosis inducers (lumican, thrombospondin 2, and galectin-1) showed higher expression in responders whereas apoptosis inhibitors (cyclophilin 40 and glutathione peroxidase) showed higher expression in nonresponders. The present study suggested the possibility that gene expression profiling may be useful in predicting response to radiotherapy to establish an individualized tailored therapy for rectal cancer. Global expression profiles of responders and nonresponders may provide insights into the development of novel therapeutic targets.

Gene expression profiles of colorectal carcinoma in response to neo-adjuvant chemotherapy.

The combination of irinotecan and a fluoropyrimidine has been widely accepted as a treatment for advanced colorectal carcinoma. However, there have been no evaluable data on the feasibility of these combinations. To assess the significance of such combinations, we attempted to identify gene expression patterns in response to irinotecan and two different types of fluoropyrimidines. In 12 patients dispositioned to receive preoperative chemotherapy for colorectal carcinoma, pre-therapy tumor biopsies and final resected specimens were available for analysis. Patients were randomly assigned to receive one of the following four regimens: (I), oral doxifluridine; (II), intravenous infusion of 5-FU; (III), intravenous infusion of irinotecan; (IV), combination of doxifluridine and irinotecan (I+III). To identify genes whose expressions changed, we analyzed the gene expression profiles prior to and after these therapies using an oligonucleotide microarray consisting of 12,000 genes. Next, we focused on the genes that demonstrated similar kinetics of altered expression in all patients in each of the regimens. We identified two proto-oncogenes, nuclear receptor of T-cells (NOT) and c-fos, that were up-regulated in doxifluridine- and irinotecan-related regimens but unchanged in the 5-FU-related regimen. Moreover, group IV tumors showed the highest apoptotic rate and lowest proliferation activity following the combined chemotherapy. These results suggest that doxifluridine has a synergistic impact on the therapeutic effect of irinotecan by up-regulating proto-oncogenes such as NOT and c-fos, and thus justify the use of one of the irinotecan and fluoropyrimidine combinations.

Plasminogen activator inhibitor-1 is a downstream mediator of the PGP9.5-related oncogenic pathway in esophageal squamous cell carcinoma.

BACKGROUND & MATERIALS AND METHODS: Recently, it has been proved that PGP9.5 is an oncogene candidate for squamous cell carcinomas. To examine the PGP9.5-related oncogenic pathway, we tested for global patterns of gene expression in cancer cells following PGP9.5 gene introduction using an oligonucleotide microarray approach. RESULTS: Plasminogen activator inhibitor-1 (PAI-1) was identified as an overexpressed gene in a PGP9.5-expressed esophageal squamous cancer cell line. To confirm the data obtained, we performed Northern analysis using a PGP9.5 or a PAI-1 cDNA probe and found that PAI-1 mRNA was induced by PGP9.5 expression in NUEC1 cells. We further examined endogenous PGP9.5 and PAI-1 expression in 6 esophageal cancer cell lines. One cell line (NUEC2) with PGP9.5 expression exhibited PAI-1 expression, suggesting the possibility that PGP9.5 might induce PAI-1 directly or indirectly. CONCLUSION: These results suggested that PAI-1 might be a novel downstream mediator of PGP9.5 in esophageal squamous cell carcinomas.

Identification of S100A2 as a target of the DeltaNp63 oncogenic pathway.

PURPOSE AND EXPERIMENTAL DESIGN: It has been proved recently that DeltaNp63 may play an oncogenic role in the tumorigenic pathway of squamous cell cancers. To gain additional insight into this pathway, we examined global patterns of gene expression in cancer cells after DeltaNp63 gene introduction using the oligonucleotide microarray approach. RESULTS: We found that S100A2 might be a target of the DeltaNp63 pathway. To confirm the data obtained from oligonucleotide microarray, we then examined the interaction of DeltaNp63 to S100A2. S100A2 induction was strictly dependent on DeltaNp63 expression by DeltaNp63 transgene and Northern analysis. DeltaNp63 transactivated the S100A2 promoter, and significantly more fold changes were seen in DeltaNp63-introduced cells than in p53-introduced cells, suggesting that DeltaNp63 may be a novel stimulator of the S100A2 promoter. CONCLUSION: Taken together, this evidence would seem to suggest that S100A2 is a novel downstream mediator of DeltaNp63.