Tae Won Kim

YM155 Induces EGFR Suppression in Pancreatic Cancer Cells

YM155, which inhibits the anti-apoptotic protein survivin, is known to exert anti-tumor effects in various cancers, including prostate and lung cancer. However, there are few reports describing the inhibitory effect of YM155 on human pancreatic cancers that highly express survivin. Here, we tested the effects of YM155 on a variety of cancer cell lines, including pancreatic cancer cells. We found that YM155 exerts an anti-proliferative effect in pancreatic cancer cells, inducing cell death through suppression of XIAP (X-linked inhibitor of apoptosis) as well as survivin without affecting the anti-apoptotic proteins Bcl-xL or Mcl-1. YM155 also inhibited tumor growth in vivo, reducing the size of pancreatic cancer cell line MIAPaCa-2 xenografts by 77.1% on day 31. Western blot analyses further showed that YM155 downregulated phosphoinoside 3-kinase (PI3K) expression and reduced the levels of phosphorylated (activated) extracellular signal-regulated kinase (ERK) and STAT3 (signal transducer and activator of transcription 3) in PANC-1 cells. Interestingly, we also found that YM155 downregulated the epidermal growth factor receptor (EGFR) in various cancer cell lines and induced the EGFR phosphorylation and ubiquitination of EGFR in PANC-1 cells. YM155 also modestly promoted the ubiquitination of survivin and XIAP. Therefore, YM155 acts through modulation of EGFR and survivin expression to subsequently reduce survival. We suggest that YM155 has potential as a therapeutic agent in the treatment of pancreatic cancer.

A phase I / II trial of docetaxel, capecitabine, and cisplatin as a first line chemotherapy for advanced gastric cancer

4066 Background: Combination of capecitabine and cisplatin (XP) was active and tolerable in advanced gastric cancer (AGC). We added docetaxel (D) to XP regimen and performed a phase I / II study of DXP combination. METHODS Patients (pts) with chemotherapy-naïve inoperable AGC were eligible for this study. For the phase I study, with the fixed dose of P (60 mg/m2 D1), the doses of X (D1-14) and D (D1) were escalated as following schedule: level 1: X 1,875 mg/m2/d, D 60 mg/m2; level 2: X 2,250 mg/m2/d, D 60 mg/m2; level 3: X 2,250 mg/m2/d, D 75 mg/m2; level 4: X 2,500 mg/m2/d, D 75 mg/m2. The cycle was repeated every 3 weeks. The phase II study was planned at the dose level just below the MTD in pts with measurable disease. RESULTS During 1st cycle, 1 DLT (neutropenic fever) among 6 pts at dose level 2 and 2 DLTs (asthenia) among 3 pts at dose level 4 were observed. During 2nd cycle, 2 DLTs were experienced among the 6 pts at dose level 3, which made the dose level 3 as MTD and the subsequent phase II study was begun at dose level 2. After total 17 pts were treated at dose level 2, frequent need for dose reduction made further phase II study performed at dose level 1. Total 40 pts with measurable disease, treated at dose level 1 (23) and 2 (17) were evaluated for phase II portion of the study. Four pts were not evaluable for response because of follow-up loss after 1 cycle of chemotherapy. After median 6 cycles of chemotherapy, there were 4 confirmed CRs and 23 confirmed PRs, with the overall response rate of 67.5% (95% C.I.: 52.7 - 82.3) in intention-to-treat analysis. There was no difference in response rate between the two dose levels. Ten pts underwent surgical resection after clinical response with 4 - 9 cycles of chemotherapy. Four pathologic CRs were identified. With a median follow-up of 14 mo. (range 1 to 28), median time to progression was 7.7 mo. (95% C.I.: 6.9 - 8.5), and median overall survival has not been reached. CONCLUSIONS Asthenia and neutropenia were DLTs in this DXP combination. The dose of D (60 mg/m2, D1), X (1,875 mg/m2/D, D1-14), and P (60 mg/m2, D1) was recommended for the 3 weekly DXP combination. The DXP chemotherapy was highly active and tolerable for the 1st line chemotherapy of AGC. [Table: see text].

Nomogram to predict ypN status after chemoradiation in patients with locally advanced rectal cancer

Background:Pelvic lymph node (LN) status after preoperative chemoradiotherapy (CRT) is an important indicator of oncologic outcome in patients with locally advanced rectal cancer. The purpose of this study was to develop a nomogram to predict LN status after preoperative CRT in locally advanced rectal cancer patients.Methods:The nomogram was developed in a training cohort (n=891) using logistic regression analyses and validated in a validation cohort (n=258) from a prospectively registered tumour registry at Asan Medical Center. The model was internally and externally validated for discrimination and calibration using bootstrap resampling. Model performance was evaluated by the concordance index (c-index) and calibration curve.Results:Pretreatment ypT stage, patient age, preCRT tumour differentiation, cN stage, lymphovascular invasion, and perineural invasion were reliable predictors of LN metastasis after preoperative CRT. The nomogram developed using these parameters had c-indices of 0.81 (training) and 0.77 (validation). The calibration plot suggested good agreement between actual and nomogram-predicted LN status after preoperative CRT.Conclusions:This nomogram improves prediction of LN status after preoperative CRT in patients with locally advanced rectal cancer. It will be useful for counselling patients as well as for the design and stratification of patients in clinical trials.

The MEK1/2 inhibitor AS703026 circumvents resistance to the BRAF inhibitor PLX4032 in human malignant melanoma cells.

Background:Although inhibitors of the proto-oncogene BRAF have shown excellent antitumor activity against malignant melanoma, their efficacy is limited by the development of acquired drug resistance, a process in which reactivation of MAP kinase (MEK) is known to play an important role. In this study, we evaluated the efficacy of AS703026, a new MEK inhibitor, in BRAF inhibitor–resistant melanoma cell lines. Methods:Two melanoma cells lines, RPMI-7951 and SK-MEL5, harboring an activating mutation of BRAF (V600E) were treated with the BRAF inhibitor PLX4032 to select a BRAF inhibitor–resistant cell line for further study. Cell viability assay was determined with MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay and trypan blue exclusion method; apoptosis assay was performed by annexin-V staining. Knockdown of BRAF was investigated by small interfering RNA. Results:RPMI-7951 cells exhibited an increased sensitivity to combined treatment with PLX4032 and AS703026 compared to either drug alone. Consistent with this, the combination of PLX4032 and AS703026 significantly induced apoptosis, whereas each drug used alone did not, as demonstrated by a flow cytometric analysis of annexin-V/propidium iodide–stained cells and Western blot analysis of cleaved caspase-3. Notably, immunoblot analyses also showed a depletion of phosphorylated-ERK with combined drug treatment. In addition, AS703026 synergized with small interfering RNA–mediated downregulation of BRAF to produce results similar to those of combined treatment with PLX4032 and AS703026. Conclusions:Our results suggest that combined treatment with AS703026 and a BRAF inhibitor overcomes the resistance to BRAF inhibitors in malignant melanoma cells harboring a mutant form of BRAF.

Investigation of papulopustular eruptions caused by cetuximab treatment shows altered differentiation markers and increases in inflammatory cytokines

Background  Epidermal growth factor receptor (EGFR) critically regulates tumour cell division, survival and metastasis. Agents that inhibit EGFR have been used in the treatment of advanced‐stage malignancies, but cause variable cutaneous side‐effects, most often papulopustular eruptions and xerosis.

A phase II study of paclitaxel and capecitabine combination chemotherapy in patients with advanced gastric cancer as a first-line therapy

4051 Background: Paclitaxel and capecitabine, which have distinct mechanisms of action and toxicity profiles, showed considerable single-agent activity in gastric cancer. Synergistic interaction between these two drugs was also suggested by taxane-induced upregulation of thymidine phosphorylase. Therefore, we evaluated antitumor activity and toxicities of paclitaxel and capecitabine combination in patients with advanced gastric cancer (AGC) as a first-line therapy. METHODS Patients with histologically confirmed AGC with unresectable or metastatic diseases, measurable lesions, PS 0-2, age between 18 and 75, and no contraindication to chemotherapy were eligible in this study. Prior adjuvant chemotherapy finished at least 6 months before enrollment was allowed. Treatment included capecitabine 825 mg/m2 p.o. twice daily on days 1-14 and paclitaxel 175 mg/m2 i.v. on day 1 every 3 weeks until disease progression or unacceptable toxicities. RESULTS Between June 2002 and December 2003, total 40 pts were enrolled in this study. The median age was 57.5 years (range, 38-73). Twenty-nine pts were male. Nine pts had recurrent disease after previous curative gastrectomy and 8 had previous adjuvant chemotherapy. After a median 4 (range, 1-9) cycles of chemotherapy, thirty-four pts were evaluable for toxicity and 33 pts for response (6 pts too early for evaluation, 1 pt loss to follow-up). In intention-to-treat analysis, the overall response rate was 52.9% (95% C.I., 36.2-69.6%), including 0 CR, 18 PRs, 9 SDs, and 6 PDs. After a median follow-up of 8.6 months (range, 0.9-17.9), median time to progression was 5.3 months (95% C.I., 3.6-6.9) and median overall survival was 14.6 months (95% C.I., 8.5-20.7). The actual dose intensity was well maintained over 95% of planned during the first 4 cycles in both drugs. Commonly observed grade 3/4 adverse events were neutropenia (41.1% of patients), hand-foot syndrome (11.8%), arthralgia (8.8%). There was no neutropenic fever or treatment-related death. CONCLUSIONS Paclitaxel and capecitabine combination chemotherapy was active and highly tolerable as a first-line therapy for AGC. No significant financial relationships to disclose.

Feasibility of proposed single-nucleotide polymorphisms as predictive markers for targeted regimens in metastatic colorectal cancer.

Background:Surrogate biomarkers for metastatic colorectal cancer (mCRC) are urgently needed to achieve the best outcomes for targeted therapy.Methods:A clinical association analysis was performed to examine the three single-nucleotide polymorphisms (SNPs) that were previously proposed as markers of chemosensitivity to the cetuximab (124 patients) and bevacizumab regimens (100 patients) in mCRC patients. In addition, biological correlations were examined for the candidate SNPs in terms of their regulatory pathway.Results:For cetuximab regimens, patients homozygous for the wild-type alleles (GG) of LIFR rs3729740 exhibited a 1.9 times greater overall response rate (ORR) and 1.4 months longer progression-free survival (PFS) than those homozygous or heterozygous for the mutant allele (GA and AA; P=0.022 and 0.027, respectively). For bevacizumab regimens, patients homozygous for the minor alleles (TT) of ANXA11 rs1049550 exhibited an ORR twice as high as those homozygous or heterozygous for the ancestral allele (CC and CT; P=0.031). Overall response rate gain was achieved up to 10% in patients with wild-type LIFR rs3729740 patients either with wild-type KRAS or skin toxicity (P=0.001) respectively. Specifically in clones treated with cetuximab and bevacizumab regimens, active p-ERK and MMP-9 expressions were significantly reduced in clones expressing wild-type LIFR rs3729740 (P=0.044) and in those expressing minor-type ANXA11 rs1049550 (P=0.007), respectively.Conclusion:LIFR rs3729740 and possibly ANXA11 rs1049550 may be useful as biomarkers for predicting whether mCRC patients are sensitive to relevant target regimens, although further validation in large cohorts is needed.

Complex Behavior of ALDH1A1 and IGFBP1 in Liver Metastasis from a Colorectal Cancer

Using our data set (GSE50760) previously established by RNA sequencing, the present study aimed to identify upregulated genes associated with colorectal cancer (CRC) liver metastasis (CLM) and verify their biological behavior. The potential roles of candidate genes in tumors were assessed using cell proliferation and invasion assays. Tissue samples were collected from 18 CRC patients with synchronous CLM and two CRC cell lines (SW480 and SW620) were used for transfection and cloning. The roles of the genes identified in CLM were verified using immunohistochemistry in 48 nude mice after intrasplenic transplantation of CRC cells. mRNA and protein expression was determined by quantitative real-time reverse transcription polymerase chain reaction and western blot, respectively. Nine genes were initially selected according to the relevance of their molecular function and biological process and, finally, ALDH1A1 and IGFBP1 were chosen based on differential mRNA expression and a positive correlation with protein expression. The overexpression of ALDH1A1 and IGFBP1 significantly and time-dependently decreased cell proliferation (p ≤ 0.001–0.003) and suppressed invasiveness by ≥3-fold over control cells (p < 0.001) in the SW480 cell line, whereas they had a slight effect on reducing SW620 cell proliferation. The protein expression levels of E-cadherin, N-cadherin, claudin-1, and vimentin were significantly higher in CLM than in primary tumor tissues (p < 0.05). However, the cadherin switch, namely, N-cadherin overexpression with reduced E-cadherin expression, was not observed in CLM tissues and transfected CRC cells. Irrespective of reduced proliferation and invasion found on in vitro cell assays, persistent overexpression of β-catenin, vimentin, and ZO-1 in IGFBP1-overexpressing SW480 cells possibly contributed to CLM development in mice implanted with IGFBP1-overexpressing SW480 cells (CLM occurrences: SW480/IGFBP1-transfected mice vs. SW480/vector- and SW480/ALDH1A1-transfected mice, 4/8 vs. 0/10, p = 0.023). In conclusion, ALDH1A1 and IGFBP1 are differentially overexpressed in CLM and may play a dual role, functioning as both tumor suppressors and metastasis promoters in CRC.

Targeting FGFR Pathway in Human Hepatocellular Carcinoma: Expressing pFGFR and pMET for Antitumor Activity

The MET receptor tyrosine kinase, the receptor for hepatocyte growth factor (HGF), has been implicated in cancer growth, invasion, migration, angiogenesis, and metastasis in a broad variety of human cancers, including human hepatocellular carcinoma (HCC). Recently, MET was suggested to be a potential target for the personalized treatment of HCC with an active HGF–MET signaling pathway. However, the mechanisms of resistance to MET inhibitors need to be elucidated to provide effective treatment. Here, we show that HCC cells exhibit different sensitivities to the MET inhibitor PHA665752, depending on the phosphorylation status of FGFR. Treatment of cells expressing both phospho-FGFR and phospho-MET with the inhibitor PHA665752 did not cause growth inhibition and cell death, whereas treatment with AZD4547, a pan-FGFR inhibitor, resulted in decreased colony formation and cleavage of caspase-3. Moreover, silencing of endogenous FGFR1 and FGFR2 by RNAi of HCC cells expressing phospho-FGFR, phospho-FGFR2, and phospho-MET overcame the resistance to PHA665752 treatment. Treatment of primary cancer cells from patients with HCC expressing both phospho-FGFR and phospho-MET with PHA665752 did not induce cell death, whereas AZD4547 treatment induced cell death through the cleavage of caspase-3. In addition, treatment of cells resistant to PHA665752 with AZD4547 abrogated the activation of downstream effectors of cell growth, proliferation, and survival. On the basis of these results, we conclude that the FGFR pathway is critical for HCC survival, and that targeting this pathway with AZD4547 may be beneficial for the treatment of patients with HCC-expressing phospho-FGFR and phospho-MET. Mol Cancer Ther; 14(11); 2613–22. ©2015 AACR.

Second-line cetuximab⁄irinotecan versus oxaliplatin⁄ fluoropyrimidines for metastatic colorectal cancer with wild-type KRAS

The goal of the present study was to compare the efficacy of the combination of cetuximab and irinotecan to the combination of oxaliplatin and fluoropyrimidines as second‐line chemotherapy in patients with irinotecan‐refractory and oxaliplatin‐naïve metastatic colorectal cancer (mCRC) harboring wild‐type KRAS. The study included 120 patients with mCRC who had progressed after irinotecan‐containing first‐line chemotherapy and were never treated with oxaliplatin; 40 patients with wild‐type KRAS were accrued prospectively in the experimental arm (arm A), and 80 patients accrued retrospectively were divided into control arms B (n = 46) and C (n = 34) according to KRAS genotype. Second‐line treatments consisted of cetuximab plus irinotecan for arm A, and oxaliplatin plus either 5‐fluorouracil (FOLFOX) or capecitabine (CapeOX) for the control arms. The median progression‐free survival (PFS) was 8.3, 5.8 and 3.9 months, for arms A, B and C, respectively, with statistical significance favoring arm A (P = 0.007). Differences in overall survival did not reach statistical significance (18.3 vs 12.6 vs 12.9, P = 0.138), although there was a trend toward longer overall survival in arm A. In terms of benefit from oxaliplatin‐containing regimens either as second‐line or third‐line therapy, the median PFS was 5.0 months in arms B and C as second‐line therapy, and 4.0 months in arm A as third‐line therapy, with no statistical significance (P = 0.385). Second‐line cetuximab plus irinotecan is a valid treatment strategy for mCRC patients with irinotecan‐refractory and oxaliplatin‐naïve tumors harboring wild‐type KRAS. Oxaliplatin‐containing chemotherapy resulted in equivalent PFS both as a second‐line and a third‐line therapy, enabling delay of the administration of FOLFOX and CapeOX until subsequent treatment cycles.