Risk factors of mFOLFOX6-induced hyperammonemia in patients with colorectal cancer: an observational study.

BACKGROUND: FOLFOX therapy, a standard treatment for colorectal cancer (CRC), causes a rare, but serious adverse event, hyperammonemia. However, the risk factors of hyperammonemia remain unknown. METHODS: We examined 74 patients who received mFOLFOX6 therapy with or without biologics for CRC between April 2013 and March 2018 in Yaizu City Hospital. Clinicopathological factors were retrospectively reviewed in association with hyperammonemia, and risk factors of hyperammonemia during mFOLFOX6 therapy were analyzed in 32 patients with the available data. RESULTS: Seven patients developed hyperammonemia, with onset exclusively on day 2 or 3 in the first cycle of therapy. They were treated with branched chain amino acid administration and hydration; however, one patient with stage G4 chronic kidney disease (CKD) died. By multivariate analysis, estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 was independently associated with hyperammonemia during FOLFOX therapy (odds ratio: 9.0, p = 0.040). CONCLUSIONS: Reduced eGFR is considered a risk factor of developing hyperammonemia during FOLFOX therapy. Serum ammonia levels should be monitored especially during the first cycle of FOLFOX therapy in patients with CKD stage G3 or higher.

[Mediastinal Thyroid Carcinoma;Report of a Case].

71-year-old woman was pointed out to have an asymptomatic mediastinal tumor. Chest computed tomography(CT) showed a well-demarcated mass measuring 7 cm in diameter in the anterior mediastinum. We resected the mass through a median sternotomy. The tumor had a clear margin without invasion to the surrounding tissue and did not show continuity with the cervical thyroid gland. Histopathologically, the tumor was diagnosed as follicular thyroid carcinoma with capsular invasion. This is an exceptionally rare case.

CD133 Expression at the Metastatic Site Predicts Patients' Outcome in Colorectal Cancer with Synchronous Liver Metastasis.

BACKGROUND: CD133 is a transmembrane protein that is proposed to be a stem cell marker of colorectal cancer (CRC); however, the correlation between CD133 expression and survival of CRC patients with liver metastasis has not been fully examined. METHODS: CD133 expression was evaluated immunohistochemically, both in primary tumors and synchronous liver metastases of 88 consecutive CRC patients, as well as recurrent lesions in the remnant liver of 27 of these 88 patients. The relationship between CD133 expression and clinicopathological characteristics, recurrence-free survival, and overall survival (OS) was analyzed. RESULTS: CD133 expression in liver metastases (mCD133) was detected in 50 of 88 patients (56.8 %), and had significant correlation with CD133 expression in primary lesions (pCD133) (p < 0.001). CD133 expression in liver recurrent lesions (recCD133) also had a significant correlation with mCD133 (p < 0.001). mCD133+ patients had significantly longer disease-free survival (p = 0.043) and OS (p = 0.014) than mCD133- patients. In addition, mCD133+ patients had a significantly lower rate of extrahepatic recurrence (p < 0.001). CONCLUSIONS: Patients without CD133 expression in liver metastasis had significantly shorter survival, perhaps because mCD133- patients had a significantly higher rate of extrahepatic recurrence.

Immunohistochemical detection of high-mobility group box 1 correlates with resistance of preoperative chemoradiotherapy for lower rectal cancer: a retrospective study.

BACKGROUND: High-mobility group box 1 (HMGB1) is a nucleoprotein that is related to inflammation. It has been implicated in a variety of biologically important processes, including transcription, DNA repair, differentiation, development, and extracellular signaling. Recently, its important role in the process of tumor invasion, metastasis, and resistance to anti-cancer therapies has been demonstrated. In this study, we aimed to investigate the correlation of HMGB1 expression and resistance of rectal cancer patients to chemoradiotherapy (CRT) prior to curative operation. METHODS: We retrospectively reviewed the data of 75 lower rectal cancer patients without complete pathological response who had received preoperative CRT and had undergone curative resection at the University of Tokyo Hospital between May 2003 and June 2010. HMGB1 expression in surgically resected specimens was evaluated using immunohistochemical detection and specimens were classified into high or low HMGB1 expression groups. Clinicopathologic features, degree of tumor reduction, regression of tumor grade, and patient survival were compared between the groups using non-paired Student's t-tests and Kaplan-Meier analysis. RESULTS: A total of 52 (69.3%) patients had high HMGB1 expression, and 23 (30.7%) had low expression. HMGB1 expression was significantly correlated with histologic type (P=0.02), lymphatic invasion (P=0.02), and venous invasion (P=0.05). Compared to patients with low HMGB1 expression, those with high expression had a poorer response to CRT, in terms of tumor reduction ratio (42.2 versus 28.9%, respectively; P<0.01) and post-CRT histological tumor regression grade (56.5 versus 30.8% grade 2; respectively; P=0.03). However, no significant correlation was found between HMGB1 expression and recurrence-free and overall survival rates. CONCLUSIONS: HMGB1 expression may be one of the key factors regulating the response of rectal cancer to preoperative CRT in terms of tumor invasiveness and resistance to therapy.

[Purtscher's retinopathy following blunt chest compression].

Following chest or abdominal injury, acute blurring of vision occurs without direct eye injury. This disease is known as Purtscher's retinopathy. A 74-year-old man suffered blunt chest injury by air bag inflation at traffic accident. Next morning, he suddenly complained of visual abnormality. An ophthalmoscopy revealed multiple cotton-wool exudation and retinal edema. He was diagnosed as Purtscher's retinopathy. The symptoms of soft exudation and retinal edema gradually resolved. The visual acuity gradually improved, but not reached to the previous level. We must be aware of this retinopathy, since this is rare but sometimes sight-threatening condition.

Hypoxia enhances colon cancer migration and invasion through promotion of epithelial-mesenchymal transition.

BACKGROUND: A hypoxic environment exists in most solid tumors because in rapidly growing tumors, the development of angiogenic vasculature is heterogenous, usually not enough to overcome the necessary oxygen supply. In an ischemic condition, cancer cells develop escape mechanisms to survive and leave the unfavorable environment. That result in the acquisition of increased potential for local invasion and evasion to distant organs. However, the escape mechanisms of cancer cells from hypoxic stress have not been fully characterized. MATERIALS AND METHODS: The human colon cancer cell line LoVo was cultured in hypoxia, and the adhesive and migratory properties were analyzed. The expression of cell surface and cytoplasmic molecules was also investigated. RESULTS: Under hypoxic conditions, cells developed epithelial-mesenchymal transition. The expression levels of α2, α5, and ß1 integrins were significantly upregulated and, as a consequence, the ability to adhere to and migrate on collagen and fibronectin was increased. On the other hand, the expression of 67-kDa laminin receptor and the abilities to adhere to and migrate on laminin were decreased. Additionally, the expression of CXCR4 was significantly increased on cells cultured in hypoxia, and the chemotactic activity to stromal cell-derived factor 1α was remarkably increased. CONCLUSIONS: Hypoxic stress induced active epithelial-mesenchymal transition in colon cancer cells, with the typical morphologic and functional changes. These morphologic and functional changes of ß1 integrins, the 67-kDa laminin receptor, and CXCR4 may be essential for the acquisition of the invasive and metastatic features in colorectal cancer.

Perianal adenocarcinoma associated with anal fistula: a report of 11 cases in a single institution focusing on treatment and literature review.

BACKGROUND/AIMS: Perianal adenocarcinoma associated with anal fistula is a rare disease with a poor prognosis. The relatively small number of patients with this disease has led to a lack of any consensus regarding diagnosis and appropriate treatment. The purpose of this study was to present our experience of 11 cases of this disease, and to highlight its clinical features, treatments and outcomes. METHODOLOGY: The patients were divided into three groups according to the modality of treatment. Four patients received surgical resection without preoperative therapy (operation group), 3 patients were treated with radiotherapy prior to surgery (RT group), and 4 were treated with combined chemoradiation therapy prior to surgery (CRT group). RESULTS: The resection stump was pathologically negative for cancer in 6 (85.7%) patients in RT or CRT group, and 3 of 6 are alive with no evidence of disease recurrence. However, the resection stump was negative in only 1 (25%) patient in the operation group. Moreover, among the patients who underwent neoadjuvant RT/CRT and abdominoperineal resection with a cancer-free resection stump, 2 patients with postoperative adjuvant therapy had no recurrence of disease. CONCLUSIONS: Multimodality therapy including neoadjuvant RT or CRT and adjuvant chemotherapy is considered to be effective for treatment of this disease.

Two cases of interparietal inguinal hernias undergoing laparoscopic treatment: a case series.

Interparietal inguinal hernia, an exceedingly rare type of inguinal hernia in which the hernia sac anatomically lies between the tissue layers of the abdominal wall, is difficult to diagnose from physical findings. Given the few reports on interparietal inguinal hernias, this condition has remained fairly unrecognized. Herein, we report the successful imaging and laparoscopic diagnoses as well as repair of an interparietal inguinal hernia. Atypical physical findings and computed tomography data help in the diagnosis of an interparietal inguinal hernia. The laparoscopic approach is useful and feasible for both the diagnosis and treatment of interparietal inguinal hernia.

Elevated neutrophil to lymphocyte ratio predicts poor prognosis in advanced colorectal cancer patients receiving oxaliplatin-based chemotherapy.

BACKGROUND: The aim of this study was to assess whether the neutrophil to lymphocyte ratio (NLR) and other laboratory markers may predict the prognosis of advanced colorectal cancer (CRC) patients receiving palliative chemotherapy. METHODS: The study population included 50 patients with far advanced or recurrent unresectable CRC who received oxaliplatin-based combination chemotherapy as first-line treatment in our hospital between June 2005 and November 2010. Seven clinical variables and 7 laboratory indices before chemotherapy were evaluated retrospectively as the possible prognostic factors of overall and progression-free survival. RESULTS: During the study period, 27 patients (54%) died of CRC. Elevated NLR (≥4.0) was observed in 15 patients (30%). By univariate analysis, elevated NLR, performance status and hypoalbuminemia were significantly associated with both poor overall and progression-free survivals. Multivariate analysis showed that elevated NLR (hazard ratio 4.39, 95% confidence interval 1.82-10.7; p = 0.0013) and thrombocytosis (hazard ratio 5.02, 95% confidence interval 1.69-13.4; p = 0.0066) were independently associated with overall survival. CONCLUSION: Elevated NLR is a powerful predictor of poor response to oxaliplatin-based chemotherapy in patients with unresectable CRC. The ratio is a simply accessible and inexpensive but useful biomarker in CRC patients receiving chemotherapy.

Resistance of colon cancer to 5-fluorouracil may be overcome by combination with chloroquine, an in vivo study.

Autophagy is a complex of adaptive cellular response that enhances cancer cell survival in the face of cellular stresses such as chemotherapy. Recently, chloroquine diphosphate (CQ), a widely used antimalarial drug, has been studied as a potential inhibitor of autophagy. Here, we aimed to investigate the role of CQ in potentiating the effect of 5-fluorouracil (5-FU), the chemotherapeutic agent of first choice for the treatment of colorectal cancer, in an animal model of colon cancer. The mouse colon cancer cell line colon26 was used. For the in-vivo study, colon26 cells were injected subcutaneously into BALB/c mice, which were treated with saline as a control, CQ (50 mg/kg/day), 5-FU (30 mg/kg/day), or the combination therapy (CQ plus 5-FU). The tumor volume ratio and body weight were monitored. After the sacrifice, tumor tissue protein extracts and tumor sections were prepared and subjected to immunoblotting for the analysis of autophagy-related and apoptosis-related proteins, and the terminal transferase uridyl end labeling assay. The combination of CQ resulted in the inhibition of 5-FU-induced autophagy and a significant enhancement in the 5-FU-induced inhibition of tumor growth. Furthermore, the combination treatment of CQ and 5-FU resulted in a significant increase in the ratio of apoptotic cells compared with other treatments. The expression levels of the proapoptotic proteins, namely Bad and Bax, were increased by the CQ treatment in the protein extracts from tumors. Our findings suggest that the combination therapy of CQ and 5-FU should be considered as an effective strategy for the treatment of colorectal cancer.

CD133(-) cells, derived from a single human colon cancer cell line, are more resistant to 5-fluorouracil (FU) than CD133(+) cells, dependent on the ß1-integrin signaling.

BACKGROUND AND AIM: Recently, the cancer stem cells (CSCs) theory has been proposed, and CD133 has been suggested as a potential marker of CSCs in various cancer types. In the present study, we aimed evaluate CD133 as a potential marker of colorectal CSCs and, for this purpose, isolated CD133(+) and CD133(-) cells from a single colorectal cancer cell line, and compared their features, especially related to the tumor-forming and differentiation abilities, and the sensitivity to chemotherapy. METHODS AND RESULTS: CD133(+) cells had higher in vivo tumor-forming ability than CD133(-) cells, and in culture, they progressively differentiated into CD133(-) cells, but not vice-versa. On the other hand, CD133(-) cells were more resistant to 5-fluorouracil (FU) treatment than CD133(+) cells, and it was found to be dependent on the higher expression of ß1-integrins, and consequently, higher ability to bind collagen. Disruption of the ß1-integrin function abrogated the chemoresistance. CONCLUSION: From the present results, we concluded that colorectal cancer CD133(+) cells, although showing some features of CSCs, are not more resistant to 5-FU than CD133(-) cells. Therefore, definite conclusions can not be drawn yet, but it is strongly suggestive that CD133 should not be used as a single CSC marker of colorectal cancer.

Six cases of primary colorectal cancer after living-donor liver transplantation: a single-institution experience in Japan.

OBJECTIVE: Liver-transplant patients have an increased risk of developing primary malignancies, possibly due to prolonged immunosuppression. However, no information on the incidence and biological characteristics of colorectal cancer after living-donor liver transplantation is available. METHODS: The medical records of 392 consecutive adult patients who had undergone living-donor liver transplantation were retrospectively analyzed. RESULTS: Colorectal cancer developed in 6 (1.5%) patients; 3 of 204 (1.5%) presented with hepatic cirrhosis, 2 of 77 (2.5%) with primary biliary cirrhosis and 1 (2.6%) of 39 with subacute fulminant hepatitis, but none of 13 patients with primary sclerosing cholangitis. Four patients were successfully treated with curative surgery and one with endoscopic resection, while another patient died 3 months after palliative surgery because of the progression of peritoneal metastasis. A pathological study revealed vessel invasion in all the five cases of surgically removed colorectal cancer and nodal metastasis in four (80%) cases. CONCLUSIONS: Colorectal cancer develops at a relatively high frequency after living-donor liver transplantation, even in non-primary sclerosing cholangitis cases, and might have high malignant potential. The screening program for colorectal cancer should be more intensified after living-donor liver transplantation compared with that in the general population.

Long-term response on letrozole for gastric cancer: A case report.

RATIONALE: Hormone therapies, particularly those targeting estrogen and its receptors, are a key treatment modality for patients with estrogen receptor (ER)-positive breast or ovarian cancer. Some gastric cancers (GCs) express ERs, and preclinical studies suggest the potential of estrogen-targeting hormone therapy on GC; however, the clinical relevance of this hormone therapy on GC treatment has not been well elucidated. PATIENT CONCERNS: An 80-year-old female was admitted to our department with hypogastric pain and vomiting. Computed tomography demonstrated small bowel obstruction, and laparotomy after bowel decompression revealed peritoneal dissemination consisting of a poorly-differentiated adenocarcinoma. Intestinal bypass between the ileum and transverse colon was performed. DIAGNOSES: The tumor was ER- and mammaglobin-positive, indicating that it originated from a breast cancer. Diagnostic imaging revealed no evidence of breast cancer; however, right axillary ER- and mammaglobin-positive lymphadenopathy was found. INTERVENTIONS: The patient received hormone therapy using letrozole based on a clinical diagnosis of occult breast cancer with peritoneal dissemination and right axillary lymph node metastasis. OUTCOMES: The patient remained disease free until 37 months but deceased at 53 months from the onset of disease. An autopsy revealed no tumor cells in the right breast tissue; however, there was a massive invasion of cancer cells in the stomach. LESSONS: A patient with ER positive GC with peritoneal dissemination and right axillary lymph node metastasis presented remarkable response to letrozole. The long-term survival obtained using letrozole for a patient with GC with distant metastasis suggests the potential of estrogen targeting hormone therapies for GC.

Use of catheter with 2-methacryloyloxyethyl phosphorylcholine polymer coating is associated with long-term availability of central venous port.

Central venous port (CVP) is a widely used totally implantable venous access device. Recognition of risks associated with CVP-related complications is clinically important for safe, reliable, and long-term intravenous access. We therefore investigated factors associated with CVP infection and evulsion, including the device type. A total of 308 consecutive patients with initial CVP implantation between January 2011 and December 2017 were retrospectively reviewed, and the association of clinical features with CVP-related complications were analyzed. Intraoperative and postoperative complications occurred in 11 (3.6%) and 39 (12.7%) patients, respectively. The overall rate of CVP availability at six months was 91.4%. Malignancy and 2-Methacryloyloxyethyl phosphorylcholine (MPC) polymer-coated catheter use were negatively associated with the incidence of CVP infections. Accordingly, malignancy and MPC polymer-coated catheter use were independent predictors for lower CVP evulsion rate (odds ratio, 0.23 and 0.18, respectively). Furthermore, both factors were significantly associated with longer CVP availability (hazard ratio, 0.24 and 0.27, respectively). This retrospective study identified factors associated with CVP-related complications and long-term CVP availability. Notably, MPC polymer-coated catheter use was significantly associated with a lower rate of CVP infection and longer CVP availability, suggesting the preventive effect of MPC coating on CVP infection.

Unresectable esophageal cancer treated with multiple chemotherapies in combination with chemoradiotherapy: A case report.

BACKGROUND: Definitive chemoradiotherapy (dCRT) using cisplatin plus 5fluorouracil (CF) with radiation is considered the standard treatment for unresectable locally advanced T4 esophageal squamous cell carcinoma (ESCC). Recently, induction chemotherapy has received attention as an effective treatment strategy. CASE SUMMARY: We report a successful case of a 59-year-old female with unresectable locally advanced T4 ESCC treated by two additional courses of chemotherapy with CF after induction chemotherapy with docetaxel, cisplatin and fluorouracil (DCF) followed by dCRT. Initial esophagogastroduodenoscopy (EGD) detected a type 2 advanced lesion located on the middle part of the esophagus, with stenosis. Computed tomography detected the primary tumor with suspected invasion of the left bronchus and 90° of direct contact with the aorta, and upper mediastinal lymph node metastasis. Pathological findings from biopsy revealed squamous cell carcinoma. We initially performed induction chemotherapy using three courses of DCF, but the lesion was still evaluated unresectable after DCF chemotherapy. Therefore, we subsequently performed dCRT treatment (CF and radiation). After dCRT, prominent reduction of the primary tumor was recognized but a residual tumor with ulceration was detected by EGD. Since the patient had some surgical risk, we performed two additional courses of CF and achieved a clinically complete response. After 14 mo from last administration of CF chemotherapy, recurrence has not been detected by computed tomography and EGD, and biopsy from the scar formation has revealed no cancer cells. CONCLUSION: We report successful case with tumor remnants even after DCF and subsequent dCRT, for whom a complete response was finally achieved with two additional courses of CF chemotherapy. Additional CF chemotherapy could be one radical treatment option for residual ESCC after treatment with induction DCF followed by dCRT to avoid salvage surgery, especially for high-risk patients.

Pancreaticoduodenectomy after neoadjuvant chemotherapy for gastric cancer invading the pancreatic head: A case report.

BACKGROUND: Pancreaticoduodenectomy (PD) for advanced gastric cancer is rarely performed because of the high morbidity and mortality rates and low survival rate. However, neoadjuvant chemotherapy for advanced gastric cancer has improved, and chemotherapy combined with trastuzumab may have a preoperative tumor-reducing effect, especially for human epidermal growth factor receptor 2 (HER2)-positive cases. CASE SUMMARY: We report a case of successful radical resection with PD after neoadjuvant S-1 plus oxaliplatin (SOX) and trastuzumab in a patient (66-year-old male) with advanced gastric cancer invading the pancreatic head. Initial esophagogastroduodenoscopy detected a type 3 advanced lesion located on the lower part of the stomach obstructing the pyloric ring. Computed tomography detected lymph node metastasis and tumor invasion to the pancreatic head without distant metastasis. Pathological findings revealed adenocarcinoma and HER2 positivity (immunohistochemical score of 3 +). We performed staging laparoscopy and confirmed no liver metastasis, no dissemination, negative lavage cytological findings, and immobility of the distal side of the stomach due to invasion to the pancreas. Laparoscopic gastrojejunostomy was performed at that time. One course of SOX and three courses of SOX plus trastuzumab were administered. Preoperative computed tomography showed partial response; therefore, PD was performed after neoadjuvant chemotherapy, and pathological radical resection was achieved. CONCLUSION: We suggest that radical resection with PD after neoadjuvant chemotherapy plus trastuzumab is an option for locally advanced HER2-positive gastric cancer invading the pancreatic head in the absence of non-curative factors.

Indirect inguinal hernia containing portosystemic shunt vessel: A case report.

BACKGROUND: Inguinal hernia repair is one of the most common general surgical operations worldwide. We present a case of indirect inguinal hernia containing an expanded portosystemic shunt vessel. CASE SUMMARY: We report a 72-year-old man who had a 4 cm × 4 cm swelling in the right inguinal region, which disappeared with light manual pressure. Abdominal-pelvic computed tomography (CT) revealed a right inguinal hernia containing an expanded portosystemic shunt vessel, which had been noted for 7 years due to liver cirrhosis. We performed Lichtenstein's herniorrhaphy and identified the hernia sac as being indirect and the shunt vessel existing in the extraperitoneal cavity through the internal inguinal ring. Then, we found two short branches between the expanded shunt vessel and testicular vein in the middle part of the inguinal canal and cut these branches to allow the shunt vessel to return to the extraperitoneal cavity of the abdomen. The hernia sac was returned as well. We encountered no intraoperative complications. After discharge, groin seroma requiring puncture at the outpatient clinic was observed. CONCLUSION: If an inguinal hernia patient has portal hypertension, ultrasound should be used to determine the contents of the hernia. When atypical vessels are visualized, they may be shunt vessels and additional CT is recommended to ensure the selection of an adequate approach for safe hernia repair.

The inhibition of autophagy potentiates anti-angiogenic effects of sulforaphane by inducing apoptosis.

BACKGROUND: Sulforaphane (SUL), a kind of isothiocyanate, has recently been focused due to its strong pro-apoptotic effect on cancer cells as well as tumor vascular endothelial cells (ECs). And recently, we demonstrated the induction of autophagy by colon cancer cells as a protective mechanism against SUL. In the present study, we aimed to investigate the possible role of autophagy induction by ECs as a defense mechanism against SUL. METHODS: Human umbilical vein endothelial cells (HUVECs) were used as the in vitro model of angiogenic ECs. The induction of autophagy was evaluated by the detection of acidic vesicular organelles (AVOs) by flow-cytometry, after the staining with acridine orange, as well as the detection of light chain 3(LC3) by Western blot. Finally, the functional implication of autophagy inhibition and SUL treatment in ECs was investigated by their ability to form vascular-like structures on Matrigel. RESULTS: Treatment of HUVECs with relatively low concentrations of SUL for 16 h resulted in the evident formation of AVOs and the recruitment of LC3 to autophagosomes, the pathognomonic features of autophagy. Co-treatment of cells with the specific autophagy inhibitor (3-methyladenine) potentiated the proapoptotic effect of SUL. And inhibition of autophagy potentiated the inhibitory effect of SUL on the ability of ECs to form capillary-like structures. CONCLUSION: Similar to cancer cells, ECs induced autophagy in response to the pro-apoptotic agent, SUL, and the inhibition of autophagy potentiated the pro-apoptotic effect. These findings open premises for the use of autophagy inhibitors in combination with anti-angiogenic agents.

Inhibition of autophagy potentiates sulforaphane-induced apoptosis in human colon cancer cells.

BACKGROUND: Sulforaphane (SUL), an isothiocyanate naturally present in widely consumed vegetables, particularly broccoli, has recently attracted attention due to its inhibitory effects on tumor cell growth by inducing apoptosis. We investigated the ability of SUL to induce autophagy in human colon cancer cells and whether inhibition of autophagy could potentiate the proapoptotic effect of SUL. METHODS: The proliferation of cells treated with SUL was assessed by MTS assay and colony-forming assay. Apoptosis and caspases activity were investigated by flow cytometry. The formation of acidic vesicular organelles (AVOs) was detected in acridine-orange-stained cells by flow cytometry. Western blotting was used for the detection of light chain 3 (LC3). Localizations of LC3 and cytochrome c were analyzed by immunocytochemistry. RESULTS: The proapoptotic effect was observed by treatment of cells with relatively high concentrations of SUL for long periods of time. After 16 h of treatment, evident formation of AVOs and recruitment of LC3 to autophagosomes, features of autophagy, were observed. Treatment of cells with a specific autophagy inhibitor (3-methyladenine) potentiated the proapoptotic effect of SUL, which was dependent on the activation of caspases and the release of cytochrome c to the cytosol. CONCLUSION: The present results demonstrate induction of autophagy in colon cancer cells as a protective reaction against the proapoptotic effect of SUL, and consequently, the potentiation of the proapoptotic effect by autophagy inhibition. These findings provide a premise for use of autophagy inhibitors in combination with chemotherapeutic agents for treatment of colorectal cancer.

Chloroquine potentiates the anti-cancer effect of 5-fluorouracil on colon cancer cells.

BACKGROUND: Chloroquine (CQ), the worldwide used anti-malarial drug, has recently being focused as a potential anti-cancer agent as well as a chemosensitizer when used in combination with anti-cancer drugs. It has been shown to inhibit cell growth and/or to induce cell death in various types of cancer. 5-Fluorouracil (5-FU) is the chemotherapeutic agent of first choice in colorectal cancer, but in most cases, resistance to 5-FU develops through various mechanisms. Here, we focused on the combination of CQ as a mechanism to potentiate the inhibitory effect of 5-FU on human colon cancer cells. METHODS: HT-29 cells were treated with CQ and/or 5-FU, and their proliferative ability, apoptosis and autophagy induction effects, and the affection of the cell cycle were evaluated. The proliferative ability of HT-29 was analyzed by the MTS assay. Apoptosis was quantified by flow-cytometry after double-staining of the cells with AnnexinV/PI. The cell cycle was evaluated by flow-cytometry after staining of cells with PI. Autophagy was quantified by flow-cytometry and Western blot analysis. Finally, to evaluate the fate of the cells treated with CQ and/or 5-FU, the colony formation assay was performed. RESULTS: 5-FU inhibited the proliferative activity of HT-29 cells, which was mostly dependent on the arrest of the cells to the G0/G1-phase but also partially on apoptosis induction, and the effect was potentiated by CQ pre-treatment. The potentiation of the inhibitory effect of 5-FU by CQ was dependent on the increase of p21Cip1 and p27Kip1 and the decrease of CDK2. Since CQ is reported to inhibit autophagy, the catabolic process necessary for cell survival under conditions of cell starvation or stress, which is induced by cancer cells as a protective mechanism against chemotherapeutic agents, we also analyzed the induction of autophagy in HT-29. HT-29 induced autophagy in response to 5-FU, and CQ inhibited this induction, a possible mechanism of the potentiation of the anti-cancer effect of 5-FU. CONCLUSION: Our findings suggest that the combination therapy with CQ should be a novel therapeutic modality to improve efficacy of 5-FU-based chemotherapy, possibly by inhibiting autophagy-dependent resistance to chemotherapy.