Prognostic Implications of Extranodal Extension in Relation to Colorectal Cancer Location / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Extranodal extension (ENE) is closely associated with the aggressiveness of both colon and rectal cancer. This study evaluated the clinicopathologic significance and prognostic impact of ENE in separate populations of patients with colon and rectal cancers. MATERIALS AND METHODS: The medical records of 2,346 patients with colorectal cancer (CRC) who underwent curative surgery at our institution between January 2003 and December 2011 were clinically and histologically reviewed. RESULTS: ENE was associated with younger age, advanced tumor stage, lymphovascular invasion (LVI), and perineural invasion (PNI) in both colon and rectal cancer. ENE rates differed significantly in patients with right colon (36.9%), left colon (42.6%), and rectal (48.7%) cancers (right vs. left, p=0.037; left vs. rectum, p=0.009). The 5-year disease-free survival (DFS) rate according to ENE status and primary tumor site differed significantly in patients with ENE-negative colon cancer (80.5%), ENE-negative rectal cancer (77.4%), ENE-positive colon cancer (68.6%), and ENE-positive rectal cancer (64.2%) (p<0.001). Multivariate analysis showed that advanced tumor stage, ENE, LVI, PNI, and absence of adjuvant chemotherapy were independently prognostic of reduced DFS in colon and rectal cancer patients. CONCLUSION: ENE is closely associated with the aggressiveness of colon and rectal cancers, with its frequency increasing from the right colon to the left colon to the rectum. ENE status is a significant independent predictor of DFS in CRC patients irrespective of tumor location. ENE might be more related with distally located CRC.

The prognostic significance and treatment modality for elevated pre- and postoperative serum CEA in colorectal cancer patients

PURPOSE: The purpose of this study was to evaluate the prognostic significance of serum CEA (s-CEA) changes in colorectal cancer (CRC) patients with sustained elevated postoperative s-CEA levels. METHODS: Between January 1999 and December 2008, 9,380 CRC patients underwent surgery. Curative resection was performed in 1,242 CRC patients with high preoperative s-CEA levels (>6 ng/mL). High s-CEA levels were normalized in 924 patients (74.4%) within 2 weeks from surgery, whereas high s-CEA levels were persistent in 318 patients (25.6%). Patients were divided into 2 groups according to their postoperative s-CEA levels: group 1 (37 patients with a 1-year postoperative s-CEA>6 ng/mL) and group 2 (281 patients with a 1-year postoperative s-CEA≤6 ng/mL). RESULTS: A postoperative recurrence was identified in 24 patients (64.9%) in group 1 and 65 patients (23.1%) in group 2 (P < 0.001). A curative resection after recurrence was performed in 22 patients (33.8%) from group 2, but no patients from group 1 (P = 0.001). The 5-year overall survival and time to recurrence were significantly lower in patients with recurrent cancer in group 1 (P < 0.001). CONCLUSION: Patients with persistent elevated postoperative s-CEA levels are at high risk for recurrence and a low survival rate. More intensive surveillance of patients with high postoperative s-CEA levels should be mandatory.

Preliminary Suggestion about Staging of Anorectal Malignant Melanoma May Be Used to Predict Prognosis / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Anorectal malignant melanomas (AMM) are rare and have poor survival. The study aims to evaluate the clinicopathologic characteristics and outcomes of patients with AMM, and to devise a staging system predictive of survival outcome. MATERIALS AND METHODS: This was a retrospective study of 28 patients diagnosed with, and treated for AMM. Patients classified by clinical staging of mucosal melanoma (MM) were reclassified via rectal and anal TNM staging. Survival outcomes were compared among patients grouped by the three different staging systems. RESULTS: The three staging systems were equated with similar figures for 5-year overall survival (OS) and 5-year disease-free survival (DFS) of patients diagnosed with stage I disease. Patients (n=19) diagnosed with MM stage II disease were reclassified by rectal TNM staging into three subgroups: IIIA, IIIB, and IIIC. For these patients, both 5-year OS and 5-year DFS differed significantly between the subgroups IIIA and IIIC (OS: IIIA vs. IIIC, 66.7% vs. 0%, p=0.002; DFS: IIIA vs. IIIC, 51.4% vs. 0%, p < 0.001). CONCLUSION: The accuracy of prognosis in patients diagnosed with AMM and lymph node metastasis has improved by using rectal TNM staging, which includes information regarding the number of lymph node metastases.

Autophagy Regulates Formation of Primary Cilia in Mefloquine-Treated Cells

Primary cilia have critical roles in coordinating multiple cellular signaling pathways. Dysregulation of primary cilia is implicated in various ciliopathies. To identify specific regulators of autophagy, we screened chemical libraries and identified mefloquine, an anti-malaria medicine, as a potent regulator of primary cilia in human retinal pigmented epithelial (RPE) cells. Not only ciliated cells but also primary cilium length was increased in mefloquine-treated RPE cells. Treatment with mefloquine strongly induced the elongation of primary cilia by blocking disassembly of primary cilium. In addition, we found that autophagy was increased in mefloquine-treated cells by enhancing autophagic flux. Both chemical and genetic inhibition of autophagy suppressed ciliogenesis in mefloquine-treated RPE cells. Taken together, these results suggest that autophagy induced by mefloquine positively regulates the elongation of primary cilia in RPE cells.

miR-27 regulates mitochondrial networks by directly targeting the mitochondrial fission factor

Mitochondrial morphology is dynamically regulated by forming small, fragmented units or interconnected networks, and this is a pivotal process that is used to maintain mitochondrial homeostasis. Although dysregulation of mitochondrial dynamics is related to the pathogenesis of several human diseases, its molecular mechanism is not fully elucidated. In this study, we demonstrate the potential role of miR-27 in the regulation of mitochondrial dynamics. Mitochondrial fission factor (MFF) mRNA is a direct target of miR-27, whose ectopic expression decreases MFF expression through binding to its 3'-untranslated region. Expression of miR-27 results in the elongation of mitochondria as well as an increased mitochondrial membrane potential and mitochondrial ATP level. Our results suggest that miR-27 is a novel regulator affecting morphological mitochondrial changes by targeting MFF.

Down-Regulation of Survivin by Nemadipine-A Sensitizes Cancer Cells to TRAIL-Induced Apoptosis

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor family of cytokines. TRAIL selectively induces apoptotic cell death in various tumors and cancer cells, but it has little or no toxicity in normal cells. Agonism of TRAIL receptors has been considered to be a valuable cancer-therapeutic strategy. However, more than 85% of primary tumors are resistant to TRAIL, emphasizing the importance of investigating how to overcome TRAIL resistance. In this report, we have found that nemadipine-A, a cell-permeable L-type calcium channel inhibitor, sensitizes TRAIL-resistant cancer cells to this ligand. Combination treatments using TRAIL with nemadipine-A synergistically induced both the caspase cascade and apoptotic cell death, which were blocked by a pan caspase inhibitor (zVAD) but not by autophagy or a necrosis inhibitor. We further found that nemadipine-A, either alone or in combination with TRAIL, notably reduced the expression of survivin, an inhibitor of the apoptosis protein (IAP) family of proteins. Depletion of survivin by small RNA interference (siRNA) resulted in increased cell death and caspase activation by TRAIL treatment. These results suggest that nemadipine-A potentiates TRAIL-induced apoptosis by down-regulation of survivin expression in TRAIL resistant cells. Thus, combination of TRAIL with nemadipine-A may serve a new therapeutic scheme for the treatment of TRAIL resistant cancer cells, suggesting that a detailed study of this combination would be useful.

Characterization of biological responses of colorectal cancer cells to anticancer regimens / 대한외과학회지

PURPOSE: Identification of subgroups of patients who differ in their response to treatment could help to establish which of the best available chemotherapeutic options are best, based on biological activity. In metastatic colorectal cancer (CRC), novel molecular-targeted agents that act on pathways that regulate cell growth, the cell cycle, apoptosis, angiogenesis, and invasion are being developed. Here, we employed an in vitro chemosensitivity assay to evaluate the biological efficacy of conventional monotherapies and combination chemotherapy with targeted drugs. METHODS: The chemosensitivities of 12 CRC cell lines to the established regimens FOLFOX (5-fluorouracil [5-FU] + leucovorin + oxaliplatin) and FOLFIRI (5-FU + leucovorin + irinotecan) and to therapy with these regimens in combination with the biologically targeted drugs bevacizumab or cetuximab were comparatively evaluated for their effects on apoptotic and autophagic cell death processes, angiogenesis, and invasion. RESULTS: Each of the chemotherapeutic regimens promoted apoptotic cell death and invasion. All drug regimens caused significantly greater apoptotic cell death with activation of caspase-3 in SW480 cells compared to other cells, effects that were associated with a remarkable reduction in matrix metalloproteinase-9 activity. The FOLFOX regimen more effectively promoted apoptotic cell death, angiogenesis, and invasion than the FOLFIRI regimen. Combination therapy with FOLFOX/FOLFIRI regimen and bevacizumab produced a moderate angiogenesis-blocking effect in most cell lines. CONCLUSION: The results validate our in vitro chemosensitivity assay, and suggest that it may be applied to help determine adequate regimens in individual CRC patients based on the biological characteristics of their tumors.

Growth and Invasion of Sporadic Colorectal Adenocarcinomas in Terms of Genetic Change

Integrative genetic changes were examined in relation to tumor growth and progression of sporadic colorectal cancers. Ninety-two sporadic colorectal cancer patients and 12 human colorectal cancer cell lines were evaluated. Genetic changes in representative steps of colorectal tumorigenesis were determined. Biological characteristics, i.e., clinicopathologic parameters, expression of invasion-associated molecules, and in vitro invasion and migration, in association with these changes were further analyzed. Adenomatous polyposis coli (APC) and/or Wnt-activated alterations occurred in 66% patients, whereas mismatch repair (MMR) defects and/or RAF-mediated alterations were identified in 47% patients. The crossover rate between these two alterations was 26%. Differential mRNA expression of ARK5 was closely associated with that of MMP2, MMP9, and S100A4 (P< or =0.044-0.001). Additionally, enhanced ARK5 mRNA expression was more frequent in tumors displaying RAF-mediated alterations and crossover pathways (P=0.01 and 0.03, respectively). Upregulation of CEA mRNA was more common in the advanced stages (P=0.034), while VEGF expression was greater in poorly differentiated or mucinous tumors (P=0.042). The high expressions of MMP2 and MMP9 were closely associated with invasion and migration of colorectal tumors and cell lines. Our results conclusively show that specific pathways of colorectal tumorigenesis are closely associated with characteristic tumor growth and invasion.

Invasiveness of and Drug Sensitivity to Various Anti-cancer Regimens in Five Colorectal Cancer Cell Lines

PURPOSE: Colorectal cancer (CRC) is one of the leading causes of cancer death in South Korea. Angiogenesis has been associated with invasion and metastasis of tumors and with the secretion of various growth factors. Bevacizumab is a humanized monoclonal antibody that recognizes and blocks vascular endothelial growth factor (VEGF) and that targets integrin alphaVbeta3 and matrix metalloproteinases (MMPs) as angiogensis inhibitors. The aims of this study were identification of the mechanism of target molecules related to angiogenesis and demonstration of identifiable invasion by using chemotherapeutic regimens in vitro. METHODS: The five colorectal cancer cell lines were treated with bevacizumab using standard or combined regimens. The expression of integrin alphaVbeta3 was detected and the investigation of apoptosis was done by using flow cytometry. The activations of MMP-2 and MMP-9 were measured by using gelatin zymography. RESULTS: The apoptotic cell death was significantly increased for the combined regimens, especially for FOLFOX (5-FU, leucovorin, and oxaliplatin) with bevacizumab. Bevacizumab inhibited the expression of integrin alphaVbeta3 in the HT29 (59%), LoVo (67%), and SW480 (17%) cell lines, but did not in the AMC5 and the RKO cell lines. The activations of MMP-2 and MMP-9 were significantly reduced by treatment with bevacizumab in the HT29 and the LoVo cell lines. In the HT29 and the LoVo cell lines, thus, bevacizumab inhibited invasion and metastasis activity through down-regulation of integrin alphaVbeta3 and MMPs. CONCLUSION: Our results provide biological evidence of potent angiogenic activity and indicate that angiogenesis is a complex process that involves multiple factors, including VEGF, integrin alphaVbeta3, and MMPs.

Comparison between Therapeutic Efficacies of Histone Deacetylase Inhibitors and Established Drug Regimens Against Breast Cancer Cells using the Histoculture Drug Response Assay / 한국유방암학회지

PURPOSE: Histone deacetylase inhibitors (HDACIs) induce accumulation of acetylated histones in nucleosomes, which lead to reactivate gene expression and inhibit the growth and survival of tumor cells. This study evaluated the efficacy of HDACIs in breast cancer cells in comparison with other established drug regimens. METHODS: Drug responses of tumor samples from mastectomy specimens of 78 breast cancer patients were evaluated using the histoculture drug response assay (HDRA). Tumor inhibition rates (IRs) of established drug regimens such as doxorubicin, cyclophosphamide, doxorubicin with cyclophosphamide (AC), paclitaxel, docetaxel and doxorubicin with docetaxel (AT), as well as those of three HDACIs (SAHA, PXD101, and a novel compound CG-2) were evaluate. RESULTS: The percentages of chemosensitive tumors (chemoresponsiveness) were 26.9-60.3% with established regimens and 61.5-73.1% with HDACIs when the cutoff value for inhibition rate was set at 30%. Breast cancer cells appeared to be more chemoresponsive to HDACIs than to established drug regimens. Chemoresponsiveness to AT was the highest among the established drug regimens. A combination regimen offered higher activity than did a single drug (doxorubicin vs AT; p<0.001). HER2/Neu-overexpressing breast cancers were chemosensitive to SAHA and AT (p=0.031 and 0.04, respectively). CONCLUSION: Our findings show that breast cancer cells were sensitive to HDACIs, with therapeutic efficacies comparable to those of established drug regimens. Specific biological markers such as HER2/Neu could be assessed for effectiveness as HDACIs chemosensitivity markers in further clinical trials.