Research ArticleExperimental Studies

Effective Timing of Surgical Resection of Colorectal Cancer Liver Metastases During Chemotherapy

SHINJI OSADA, AYANA GOTOH, RYOMA YOKOI, HIROSHI TSUCHIYA, TAKUJI SAKURATANI, YOSHIYUKI SASAKI, NAOKI OKUMURA, HIDEKI HAYASHI and TSUYOSHI MUKAI
Anticancer Research February 2018, 38 (2) 737-743;

Abstract

Background/Aim: The aim of the present study was to further develop our previous study on c-Met expression in colorectal cancer and epithelial-mesenchymal transition (EMT) induced by hepatocyte growth factor (HGF), to investigate EMT in the process of liver metastases, and evaluate the effects of chemotherapy on EMT cells as a therapeutic strategy for colorectal liver metastasis. Materials and Methods: CT26 colon cancer cells were treated with 5-FU and oxaliplatin with or without HGF. The signaling pathway was evaluated by western blotting analysis, and drug resistance was evaluated by the MTT (3-(4,5-dimethyl-2-tetrazolyl)-2,5-diphenyl-2H tetrazolium bromide) assay. Results: Under pretreatment with HGF for 96 h, 5 μM and 10 μM of 5-FU mediated significant growth inhibition by 72.5±3.9% and 76.2±2.4%, respectively, compared to HGF alone, and by 105.1±2.8% and 103.5±2.9%, respectively, without HGF. The expression of E2F1 was decreased significantly to 50.5±3.8% after 24 hours by HGF with a reduction of both cyclin D1 to 52.1±7.0% and E to 73.7±3.8%. Thymidylate synthase was also decreased in a time-dependent manner to 80.6±2.0% after 24 h and to 52.7±1.5% after 96 h. Conclusion: The presence of HGF was found to increase the 5-FU-induced death signal, JNK pathway, and inhibition of cell growth. As its mechanism, HGF was shown to decrease E2F-1 by reducing cyclin D or E by cell-cycle activation, resulting in inactivation of thymidylate synthase. The chemotherapeutic effect of 5-FU was increased in HGF- but not TGF-β-induced EMT.

Colorectal cancer (CRC) is the third most common epithelial malignancy worldwide (1). Liver metastases developed from CRC represent one of the most frequent causes of death, affecting approximately 70% of patients (2). Improved combinations of 5-fluorouracil (5-FU)/folinic acid with irinotecan (FOLFIRI) or oxaliplatin (FOLFOX) have progressively increased tumor response to 73%, and the median survival time has risen to 20 months (3). Surgical resection has also remained an expected procedure to ensure long-term survival or cure (4). More favorable survival rates are obtained with preoperative chemotherapy compared to surgery alone (5), and combination of these treatments achieves 5-year survival rates of up to 60% (6). However, in the process of liver regeneration after hepatectomy, the relation between the activation of the hepatocyte growth factor (HGF)-induced its receptor, c-Met, signaling pathway and cancer progression remains unknown (7).

Epithelial-mesenchymal transition (EMT) is a process by which differentiated epithelial cells transition to a mesenchymal phenotype. EMT enables the escape of epithelial cells from the rigid structural constraints of the tissue architecture to a phenotype more amenable to cell migration, thus, creating invasion and metastasis (8). Among various soluble factors to correlate with EMT, HGF is related to poor prognosis of patients with small cell lung cancer through a high rate of metastasis to several organs (9) and directly promotes carcinogenesis of hepatocellular carcinoma (10). On the other hand, the early response to anticancer agents in the progress of EMT is still unclear and controversial. Some reports showed EMT to relate to higher chemosensitivity (11), whereas its expression has also been related to lower chemosensitivity (12). To clarify this, we showed that pretreatment of CRC cells with HGF enhanced 5-FU-induced cell death by 63% compared with the control during the expression of signaling pathway by HGF/c-Met activation (1); however, its mechanism remains unclear. The purpose of the present study was to further develop our previous study on c-Met expression in CRC and EMT induced by HGF, to investigate EMT in the process of liver metastases, and to evaluate the effects of chemotherapy on EMT cells as a therapeutic strategy for colorectal liver metastasis.

Materials and Methods

Cell lines and culture conditions. Cells from the CT26 murine colorectal carcinoma cell line were obtained from the American Type Culture Collection (ATCC, Manassas, VA, USA). Cells were cultured in RPMI-1640 medium (Wako, Osaka, Japan) supplemented with 10% heat-inactivated fetal bovine serum (FBS), 1 mM HEPES buffer, 1 mM sodium pyruvate solution, and 1% penicillin-streptomycin-amphotericin solution (all from Sigma-Aldrich, St. Louis, MO, USA) in a humidified atmosphere of 5% CO2/95% air at 37°C. Cells were passaged twice a week.

Cell proliferation assay. Cell growth was assessed by a standard 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay (1, 7), which detects the dehydrogenase activity in viable cells. A total of 5×103 CT26 cells were seeded into each of the 96-well culture plates or the same density of cells was seeded into 6-well culture plates overnight and kept in a humidified atmosphere of 5% CO2 and 95% air at 37°C. The medium was exchanged for serum-free RPMI-1640 medium, and after 48-h incubation, growth stimulation by growth factors was started by adding 5 ng/ml of transforming growth factor-β (TGFβ) and 20 ng/ml of HGF to each well in the same condition. Recombinant TGF-β1 and recombinant HGF were purchased from R&D Systems (Minneapolis, MN, USA). After 0, 24, 48, 72 or 96 h, 0, 5 or 10 μM of 5-FU was added to the culture medium. After 48-h incubation, 100 μl of a 0.5 mg/ml solution of MTT (Sigma-Aldrich, Darmstadt, Germany) was added to each well. The plates were then incubated for 4 h at 37°C. The culture medium was replaced with 100 μl of dimethyl sulfoxide (Wako, Osaka, Japan) per well, and the absorbance at the 540-nm wavelength was measured using a 2104 EnVision Multilabel Reader (Perkin-Elmer, Waltham, MA, USA).

Western blot analysis and antibodies. Treatment of the specimens was as described previously (1, 7). Cell lysates were boiled in Sample Buffer Solution (Wako, Osaka, Japan). Total cell protein extracts (20 or 40 μg/lane) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis using SuperSep™ (Wako, Osaka, Japan) and were electrophoretically transfected onto polyvinyl difluoride membranes. The membranes were blocked with PVDF blocking reagent (Toyobo, Osaka, Japan) for 1 h. The membranes were then incubated overnight at 4°C with primary antibodies against Notch1 (D1E11) XP rabbit mAb (Cell Signaling Technology, Denver, MA, USA), β-catenin rabbit mAb (Cell Signaling Technology, Denver, MA, USA), ZEB1 antibody (NOVUS Biologicals, Littleton, CO, USA), phospho-c-Jun N-terminal kinase (JNK) mouse mAb (Cell Signaling Technology, Denver, MA, USA), phospho p44/42 MAP kinase (Erk1/2) antibody (Cell Signaling Technology, Denver, MA, USA), cleaved PARP (Asp214) antibody (Cell Signaling Technology, Denver, MA, USA), caspase-3 antibody, cyclinB1 antibody (Cell Signaling Technology, Denver, MA, USA), cyclinD1 rabbit mAb (Cell Signaling Technology, Denver, MA, USA), cyclinE mouse mAb, anti-E2F1 antibody (ab96864) (Abcam, Cambridge, UK), thymidine synthase antibody (kindly provided TAIHO, Tokyo, Japan), and phospho-NF-ĸBp65 (Ser468) antibody (Cell Signaling Technology, Denver, MA, USA). The primary antibodies were diluted with Can Get Signal Solution 1 (Toyobo, Osaka, Japan). The membranes were then washed with Dako Washing Buffer (Dako, Glostrup, Denmark) and incubated with the appropriate secondary antibodies (1:25.000; Millipore, Darmstadt, Germany), which were diluted with Can Get Signal Solution 2 (Toyobo, Osaka, Japan). The immunoreactive proteins were visualized by chemiluminescence using ImmunoStar LD reagents (Wako, Osaka, Japan), and images were captured by a GeneGnome Bio Imaging System (Syngene, Cambridge, UK). The detected band was analyzed by ImageJ computer software, as described previously. Each value was obtained from the comparison with the level of rabbit polyclonal anti β-actin (Abcam, Tokyo, Japan), and the mean values were calculated from three repeated measures (13).

Statistical analysis. The data were examined using the Student t-test, Chi-square test, and ANOVA or Kruskal-Wallis test (with appropriate post hoc analysis for multiple comparisons) to determine statistical significances. p-Values of less than 0.05 were regarded as statistically significant.

Results

Mediated signal pathway. In the CT26 mouse CRC cells, the IC50 by 5-FU at 48 h was determined to be 24.0±2.0 mM. 5-FU-induced cell signaling pathways for the CT26 cell line were evaluated (Figure 1). Compared with the bands detected by Western blotting in the control, 5-FU increased activated JNK to 226.4±34.4% and reduced ERK phosphorylation to 48.1±1.8% after 30 min, and increased cleaved-type PARP to 569.9±2.0% and caspase-3 to 154.7±1.1%, as an apoptosis pathway, after 12 h. 5-FU also decreased the amount of cyclin B1 to 68.4±4.0% and increased cyclin D1 to 153.9±9.0% after 24 h. The effect of oxaliplatin as another common chemotherapeutic agent for CRC on cell growth and the signaling pathway was examined (Figure 2). The IC50 of oxaliplatin was 84.0±12.2 μM, and it increased the activated type of both JNK and ERK to 106.2±0.8% and 132.2±40.7%, respectively, after 30 min, and the apoptosis pathway cleaved PARP to 836.9±115.9% and caspase-3 to 742.5±148.1% after 12 h in a dose-dependent manner. Oxaliplatin was also found to decrease both cyclin B1 and D1 to 16.1±0.8% and 14.5±1.3% after 24 h, respectively.

The signaling pathway related to EMT was also studied (Figure 3). Both TGFβ as the most common inducer for EMT and HGF decreased the expression of E-cadherin to 39.0±0.2% and 51.1±1.0% for 72 h or more. TGF-β induced the activation of ZEB1 to 151.3±9.1% after 24 h and Notch1 to 51.5±3.4% after 48 h and decreased the expression of β-catenin in a time-dependent manner. The activation of these pathways was not detected by HGF, and as a factor of anti-cancer drug resistance, NFkB was not activated by either TGF-β or HGF.

The effect of 5-FU on the action of HGF to induce EMT was studied (Figure 4). Under pretreatment with HGF for 96 h, 5 μM and 10 μM 5-FU mediated significant growth inhibition by 72.5±3.9% and 76.2±2.4%, respectively, compared with HGF alone, and by 105.1±2.8% and 103.5±2.9%, respectively, without HGF. From observations of the signaling pathway, 5-FU-induced JNK activation was significantly increased by pretreatment with HGF, but not with TGF-β, for 72 or 96 h, but not by simultaneous applications. These signaling actions were not shown by oxaliplatin (data not shown).

Figure 1.
Figure 1.

5-FU-induced cell signaling pathway. 5-FU mediated the activation of JNK and reduced phosphorylation of ERK after 30 minutes (A). The cleaved band of PARP or caspase-3 was detected by incubation with 25 mM or 10 mM of 5-FU, respectively, for 12 h (B). Cyclin B1 was decreased and cyclin D1 was increased by incubation with 10 mM of 5-FU for 24 h (C). Cell death was high when 25 mM of 5-FU was used, and an inadequate amount of protein was obtained.

Figure 2.
Figure 2.

Oxaliplatin-mediated cell signaling pathway. Oxaliplatin mediated the activation of JNK, but not ERK, after 30 min (A). The cleaved band of PARP or caspase-3 was detected by incubation with >25 mM of oxaliplatin for 12 h in a dose-dependent manner (B). Both cyclin B1 and D1 were decreased by incubation with 25 mM of oxaliplatin for 24 h (C).

To estimate the mechanism of the HGF-mediated increase in the effect of 5-FU, a study of its metabolic enzymes was performed (Figure 5). The expression of E2F1 was decreased significantly to 50.5±3.8% after 24 h by HGF with a reduction of both cyclin D1 and E to 52.1±7.0% and 73.7±3.8%, respectively. Thymidylate synthase (TS) was also decreased in a time-dependent manner to 80.6±2.0% and 52.7±1.5% for 24 and 96 h, respectively.

Figure 3.
Figure 3.

EMT signaling pathway. Both TGF-β and HGF decreased the expression of E-cadherin, and TGF-β induced the activation of ZEB1/Notch1 and decreased the expression of β-catenin in a time-dependent manner, but the activation of these pathways was not detected by HGF (A). A factor of anti-cancer drug resistance, NFkB was not activated by either TGF-β or HGF, despite both being detected by a positive factor, tumor necrosis factor-α (B).

Discussion

EMT is demonstrated as a loss of epithelial markers, such as E-cadherin or a gain of mesenchymal markers, such as the vimentin and the ZEB family of proteins (14). TGF-β is essential for the induction of EMT during various stages of embryogenesis and is important in the progression of carcinoma to an invasive state. As well, Notch, the surface receptor related to TGFβ/Smad, is important not only in the mediation of EMT (15), but also the survival of cancer cells (16). In the present study, the expression of E-cadherin was decreased with the activation of Notch1 and ZEB1 by TGF-β. In contrast, HGF was found to reduce E-cadherin but showed no effects on either Notch 1 or ZEB1. In fact, because substantial activation of the HGF/c-Met pathway leads to scattering of cancer cells (17), the suggestion that HGF regulates EMT might be possible. In the process of hepatocyte to hepatoma, HGF leads to the decreased expression of E-cadherin and an increase in vimentin through not only common EMT pathway but also some other signaling factors (10). In our previous report on the same cell line (1), during the activation of the HGF/c-Met pathway, mitogen-activated protein kinase or phosphoinositide 3-kinase was shown to act as a key point to induce EMT independently from main EMT pathway, and this was supported by recent reports (18, 19). The process of EMT is also important in conferring drug resistance to several cancer cells against conventional therapeutics including oxaliplatin (20). NF-ĸB is regulated with drug resistance-related gene expression in cancer cells, and its inhibition increases drug-sensitivity for chemotherapy, indicating that NF-ĸB itself acts as one of the drug-resistant factors. In fact, NF-ĸB activation was recently implicated in EMT, and reversal of EMT was triggered by NF-ĸB inhibition (21). However, in the present study, NF-ĸB was not activated by either TGF-β or HGF, indicating that the drug-resistant manner of EMT was not related in this cell line. These differences in signaling pathways mediating the effect of chemotherapeutic agents are not yet clear, but there is a possibility of the NF-ĸB-independent appearance of EMT (22).

Figure 4.
Figure 4.

The effect of HGF for 5-FU-induced growth inhibition. The presence of HGF increased 5-FU-induced growth inhibition by MTT assay (A). 5-FU-induced JNK activation was clearly increased by pretreatment with HGF for 72 or 96 h (B). Each band was evaluated by computer software and the percentage of the comparison with each band of β-actin was calculated.

5-FU, which has held a central position in chemotherapy for several solid types of cancer, is a critical factor in the recently developed FOLFOX or FOLFILI regimens. It is the first rationally designed anti-metabolite to achieve its therapeutic efficacy through inhibition of DNA repair and its metabolism is regulated mainly by enzymes such as TS (23). CRC patients with low levels of TS were reported to have better prognosis than those with high levels (24), and gene amplification of TS with consequent increases in mRNA and protein expression was observed in a 5-FU-resistant cell line (25). Taken together, the expression of TS appears to be a more useful indicator for the prediction of chemosensitivity. As the transcriptional factor of TS, E2F reverses to an activated style, by splitting of the complex with phospho-retinoblastoma (Rb) protein, and regulates TS expression (26). The D-type cyclins play a critical role in the early G1 phase of the cell cycle and the complex with its related-factors phosphorylate the Rb protein and inactivate its ability to act as a transcriptional repressor in a complex with E2F. The release of E2F leads to transcriptional induction of genes required for progression from the G1 to S phase, most notably cyclin E. Therefore, down-regulation of cyclin D1 mediates the shutdown of E2F-mediated transcriptional activity (27). This leads to the dissociation of the pRb/E2F complex and the subsequent release of the transcriptional activity of E2Fs (28). The present study showed that pretreatment with HGF induced the EMT-mediated higher sensitivity of 5-FU, and these results were supported by the TS/E2F theory with the cell cycle. Among the MAPKs to transmit extracellular signals to regulate cell proliferation, apoptosis and autophagy, JNK is commonly known as a response to antitumor agents or death signals (29). In addition, 5-FU-induced JNK activation is critical to the initiation of cancer cell apoptosis. Then, the increased expression of 5-FU-induced JNK by HGF will induce HGF-mediated EMT to increase the sensitivity to 5-FU.

Figure 5.
Figure 5.

The mechanism of the increased effect of 5-FU induced by HGF. The expression of E2F1 was decreased at 24 h after addition of HGF with reduction of cyclin D1 and E (A). Thymidylate synthase (TS) was clearly decreased after 24 hours in a time-dependent manner (B). Each band was evaluated by computer software and the percentage of the comparison with each band of β-actin was calculated.

In conclusion, the presence of HGF was found to increase the 5-FU-induced death signal because the decrease of E2F-1 by HGF inactivated TS. A previous study revealed that the best procedure for favorable patient prognosis was to plan a hepatectomy after administration of FOLFOX for 12 weeks and rest for 4 weeks (7, 30). The present study may lead to a novel concept in which a hepatectomy-induced high serum level of HGF for liver regeneration allows drug-resistant cancer cells to become sensitive again through the process of EMT.

  • Received November 14, 2017.
  • Revision received November 28, 2017.
  • Accepted November 29, 2017.

References

  1. ↵
    1. Tanahashi T,
    2. Osada S,
    3. Yamada A,
    4. Kato J,
    5. Yawata K,
    6. Mori R,
    7. Imai H,
    8. Sasaki Y,
    9. Saito S,
    10. Tanaka Y,
    11. Nonaka K,
    12. Yoshida K
    : Extracellular signal-regulated kinase and Akt activation play a critical role in the process of hepatocyte growth factor-induced epithelial-mesenchymal transition. Int J Oncol 42: 556-564, 2013.
    OpenUrlPubMed
  2. ↵
    1. Koh SL,
    2. Ager EI,
    3. Costa PL
    : Blockade of the renin-angiotensin system inhibits growth of colorectal cancer liver metastases in the regenerating liver. Clin Exp Metastasis 31: 395-405, 2014.
    OpenUrl
  3. ↵
    1. Grothey A,
    2. Sargent D,
    3. Goldberg RM
    : Survival of patients with advanced colorectal cancer improves with the availability of fluorouracil-leucovorin, irinotecan, and oxaliplatin in the course of treatment. J Clin Oncol 22: 1209-1214, 2004.
    OpenUrlAbstract/FREE Full Text
  4. ↵
    1. Elliott VA,
    2. Rychahou P,
    3. Zaytseva YY,
    4. Evers BM
    : Activation of c-Met and upregulation of CD44 expression are associated with the metastatic phenotype in the colorectal cancer liver metastasis model. PLoS One 9: e97432, 2014.
    OpenUrl
  5. ↵
    1. Osada S,
    2. Imai H,
    3. Sasaki Y,
    4. Tanaka Y,
    5. Okumura N,
    6. Nonaka K,
    7. Takahashi T,
    8. Yamaguchi K,
    9. Yoshida K
    : Surgical indications for multiple and synchronous liver metastases from colorectal cancer. Hepatogastroenterology 61: 722-726, 2014.
    OpenUrl
  6. ↵
    1. Viganò L,
    2. Capussotti L,
    3. Lapointe R,
    4. Barroso E,
    5. Hubert C,
    6. Giuliante F,
    7. Ijzemans JN,
    8. Miza DF,
    9. Elias D,
    10. Adam R
    : Early recurrence after liver resection for colorectal metastases: risk factors, prognosis, and treatment. A LiverMetSurvey-based study of 6,025 patients. Ann Surg Oncol 21: 1276-1286, 2014.
    OpenUrlCrossRefPubMed
  7. ↵
    1. Sasaki Y,
    2. Osada S,
    3. Mori R,
    4. Imai H,
    5. Tanaka Y,
    6. Matsuhashi N,
    7. Okumuara N,
    8. Nonaka K,
    9. Takahashi T,
    10. Yoshida K
    : Determining timing of hepatectomy for colorectal cancer with distant metastasis according to imaging-based tumor shrinkage ratio. Int J Med Sci 10: 1231-1241, 2013.
    OpenUrl
  8. ↵
    1. Jahn SC,
    2. Law ME,
    3. Corsino PE,
    4. Parker NN,
    5. Pham K,
    6. Davis BJ,
    7. Lu J,
    8. Law BK
    : An in vivo model of epithelial to mesenchymal transition reveals a mitogenic switch. Cancer Lett 326: 183-190, 2012.
    OpenUrlPubMed
  9. ↵
    1. Cañadas I,
    2. Taus A,
    3. González I,
    4. Villiaueva X,
    5. Gimero J,
    6. Pijuan L,
    7. Domine M,
    8. Sanchez-Font A,
    9. Vollmer I,
    10. Menendez S,
    11. Arpi O,
    12. Mojal S,
    13. Rojo F,
    14. Rovira A,
    15. Albaneell J,
    16. Arriola E
    : High circulating hepatocyte growth factor levels associate with epithelial to mesenchymal transition and poor outcome in small cell lung cancer patients. Oncotarget 5: 5246-5256, 2014.
    OpenUrlCrossRef
  10. ↵
    1. Ogunwobi OO,
    2. Liu C
    : Hepatocyte growth factor upregulation promotes carcinogenesis and epithelial-mesenchymal transition in hepatocellular carcinoma via Akt and COX-2 pathways. Clin Exp Metastasis 28: 721-731, 2011.
    OpenUrlCrossRefPubMed
  11. ↵
    1. Koo JS,
    2. Jung W,
    3. Jeong J
    : The predictive role of E-cadherin and androgen receptor on in vitro chemosensitivity in triple-negative breast cancer. Jpn J Clin Oncol 39: 560-568, 2009.
    OpenUrlCrossRefPubMed
  12. ↵
    1. Nakamura T,
    2. Kato Y,
    3. Fuji H,
    4. Horiuchi T,
    5. Chiba Y,
    6. Tanaka K
    : E-cadherin-dependent intercellular adhesion enhances chemoresistance. Int J Mol Med 12: 693-700, 2003.
    OpenUrlPubMed
  13. ↵
    1. Matsui S,
    2. Osada S,
    3. Tomita H,
    4. Komori S,
    5. Mori R,
    6. Sanada Y,
    7. Takahasshi T,
    8. Yamaguchi K,
    9. Yoshida K
    : Clinical significance of aggressive hepatectomy for colorectal liver metastasis, evaluated from the HGF/c-Met pathway. Int J Oncol 37: 289-297, 2010.
    OpenUrlPubMed
  14. ↵
    1. Lamouille S,
    2. Xu J,
    3. Derynck R
    : Molecular mechanisms of epithelial-mesenchymal transition. Nat Rev Mol Cell Biol 15: 178-196, 2014.
    OpenUrlCrossRefPubMed
  15. ↵
    1. Kopan R,
    2. Ilagan MX
    : The canonical Notch signaling pathway: unfolding the activation mechanism. Cell 137: 216-233, 2009.
    OpenUrlCrossRefPubMed
  16. ↵
    1. Xing F,
    2. Okuda H,
    3. Watabe M,
    4. Kobayashi M,
    5. Pai SK,
    6. Liu W,
    7. Pandey PR,
    8. Fukuda K,
    9. Hirota S,
    10. Sugai T,
    11. Wabayashi G,
    12. Koeda K,
    13. Kashiwaba M,
    14. Suzuki K,
    15. Chiba T,
    16. Endo M,
    17. Mo YY,
    18. Watanabe K
    : Hypoxia-induced Jagged2 promotes breast cancer metastasis and self-renewal of cancer stem-like cells. Oncogene 30: 4075-4086, 2011.
    OpenUrlCrossRefPubMed
  17. ↵
    1. Gregorini M,
    2. Bosio F,
    3. Rocca C,
    4. Corradetti V,
    5. Valsania T,
    6. Pattonieri EF,
    7. Bedino G,
    8. Collesi C,
    9. Libetta C,
    10. Frassoni F,
    11. Dal Canton A,
    12. Rampino T
    : Mesenchymal stromal cells reset the scatter factor system and cytokine network in experimental kidney transplantation. BMC Immunol 15: 44, 2014.
    OpenUrl
  18. ↵
    1. Dong P,
    2. Konno Y,
    3. Watari H,
    4. Hosaka M,
    5. Noguchi M,
    6. Sakuragi N
    : The impact of microRNA-mediated PI3K/AKT signaling on epithelial-mesenchymal transition and cancer stemness in endometrial cancer. J Transl Med 12: 231, 2014.
    OpenUrlCrossRefPubMed
  19. ↵
    1. Luo BH,
    2. Xiong F,
    3. Wang JP,
    4. Li JH,
    5. Zhong M,
    6. Liu QL,
    7. Yang XJ,
    8. Xiao N,
    9. Xie B,
    10. Xiao H,
    11. Liu RJ,
    12. Dong CS,
    13. Wang KS,
    14. Wen JF
    : Epidermal growth factor-like domain-containing protein 7 (EGFL7) enhances EGF receptor-AKT signaling, epithelial-mesenchymal transition, and metastasis of gastric cancer cells. PLoS One 9: e99922, 2014.
    OpenUrlCrossRefPubMed
  20. ↵
    1. Wang Z,
    2. Li Y,
    3. Ahmad A,
    4. Azmi AS,
    5. Kong D,
    6. Banerjee S,
    7. Sarkar FH
    : Targeting miRNAs involved in cancer stem cell and EMT regulation: An emerging concept in overcoming drug resistance. Drug Resist Updat 13: 109-118, 2010.
    OpenUrlCrossRefPubMed
  21. ↵
    1. Naugler WE,
    2. Karin M
    : NF-kappaB and cancer-identifying targets and mechanisms. Curr Opin Genet Dev 18: 19-26, 2008.
    OpenUrlCrossRefPubMed
  22. ↵
    1. Bentires-Alj M,
    2. Barbu V,
    3. Fillet M,
    4. Chariot A,
    5. Relic B,
    6. Jacobs N,
    7. Gielen J,
    8. Merville MP,
    9. Bours V
    : NF-kappaB transcription factor induces drug resistance through MDR1 expression in cancer cells. Oncogene 22: 90-97, 2003.
    OpenUrlCrossRefPubMed
  23. ↵
    1. Vinod BS,
    2. Antony J,
    3. Nair HH,
    4. Puliyappadamba VT,
    5. Saikia M,
    6. Narayanan SS,
    7. Bevin A,
    8. Anto RJ
    : Mechanistic evaluation of the signaling events regulating curcumin-mediated chemosensitization of breast cancer cells to 5-fluorouracil. Cell Death Dis 4: e505, 2014.
    OpenUrl
  24. ↵
    1. Kumamoto K,
    2. Kuwabara K,
    3. Tajima Y,
    4. Amano K,
    5. Hatano S,
    6. Ohsawa T,
    7. Okada N,
    8. Ishibashi K,
    9. Haga N,
    10. Ishida H
    : Thymidylate synthase and thymidine phosphorylase mRNA expression in primary lesions using laser capture microdissection is useful for prediction of the efficacy of FOLFOX treatment in colorectal cancer patients with liver metastasis. Oncol Lett 3: 983-989, 2014.
    OpenUrl
  25. ↵
    1. Johnston PG,
    2. Drake JC,
    3. Trepel J,
    4. Allegra CJ
    : Immunological quantitation of thymidylate synthase using the monoclonal antibody TS 106 in 5-fluorouracil-sensitive and -resistant human cancer cell lines. Cancer Res 52: 4306-4312, 1992.
    OpenUrlAbstract/FREE Full Text
  26. ↵
    1. Banerjee D,
    2. Gorlick R,
    3. Liefshitz A,
    4. Danenberg K,
    5. Danenberg PC,
    6. Danenberg PV,
    7. Klimsta D,
    8. Jhanwar S,
    9. Cordon-Cardo C,
    10. Fong Y,
    11. Kemeny N,
    12. Bertino JR
    : Levels of E2F-1 expression are higher in lung metastasis of colon cancer as compared with hepatic metastasis and correlate with levels of thymidylate synthase. Cancer Res 60: 2365-2367, 2000.
    OpenUrlAbstract/FREE Full Text
  27. ↵
    1. Kobayashi S,
    2. Shimamura T,
    3. Monti S,
    4. Steidl U,
    5. hetherington CJ,
    6. Lowell AM,
    7. Golub T,
    8. Meyerson M,
    9. Tenen DG,
    10. Shapiro GI,
    11. Halmos B
    : Transcriptional profiling identifies cyclin D1 as a critical downstream effector of mutant epidermal growth factor receptor signaling. Cancer Res 66: 11389-11398, 2006.
    OpenUrlAbstract/FREE Full Text
  28. ↵
    1. Leshem Y,
    2. Halevy O
    : Phosphorylation of pRb is required for HGF-induced muscle cell proliferation and is p27kip1-dependent. J Cell Physiol 191: 173-182, 2002.
    OpenUrlCrossRefPubMed
  29. ↵
    1. Sui X,
    2. Kong N,
    3. Wang X,
    4. Fang Y,
    5. Hu X,
    6. Xu Y,
    7. Chen W,
    8. Wang K,
    9. Li D,
    10. Lin W,
    11. Lou F,
    12. Zheng Y,
    13. Hu H,
    14. Gong L,
    15. Zhou X,
    16. Pan H,
    17. Han W
    : JNK confers 5-fluorouracil resistance in p53-deficient and mutant p53-expressing colon cancer cells by inducing survival autophagy. Sci Rep 4: 4694, 2014.
    OpenUrl
  30. ↵
    1. Osada S,
    2. Imai H,
    3. Sasaki Y,
    4. Tanaka Y,
    5. Tokuyama Y,
    6. Okumura N,
    7. Nonaka K,
    8. Takahahi T,
    9. Yamaguchi K,
    10. Yoshida K
    : Strategy for synchronous and multiple liver metastasis. Hepatogastroenterology 59: 198-203, 2012.
    OpenUrlPubMed
Back to top

In this issue

Print
Download PDF
Article Alerts
Email Article
Citation Tools
Reprints and Permissions
Effective Timing of Surgical Resection of Colorectal Cancer Liver Metastases During Chemotherapy
SHINJI OSADA, AYANA GOTOH, RYOMA YOKOI, HIROSHI TSUCHIYA, TAKUJI SAKURATANI, YOSHIYUKI SASAKI, NAOKI OKUMURA, HIDEKI HAYASHI, TSUYOSHI MUKAI
Anticancer Research Feb 2018, 38 (2) 737-743;
Reddit logo Twitter logo Facebook logo Mendeley logo

Jump to section

Keywords