Caffeic Acid Enhances Anticancer Drug-induced Apoptosis in Acid-adapted HCT116 Colon Cancer Cells.

BACKGROUND/AIM: Apoptosis resistance in cancer cells adapted to acidic microenvironments poses a challenge for effective treatment. This study investigated the potential use of caffeic acid as an adjunct therapy to overcome drug resistance in colorectal cancer cells under acidic conditions. MATERIALS AND METHODS: Long-term exposure to low-pH conditions induced resistance in HCT116 colorectal cancer cells. The effects of caffeic acid on proliferation, clonogenicity, and apoptosis induction were assessed alone and in combination with oxaliplatin and 5-Fluorouracil. The signaling pathways involved in drug resistance were examined by assessing the activities of PI3K/Akt and ERK1/2. RESULTS: Caffeic acid inhibited the proliferation and clonogenicity of acid-adapted cancer cells, and enhanced apoptosis when combined with anticancer drugs. Mechanistically, caffeic acid attenuated the hyperactivation of the PI3K/Akt and ERK1/2 signaling pathways associated with drug resistance. CONCLUSION: Caffeic acid is a promising therapeutic agent for targeting resistant cancer cells in acidic microenvironments. Its ability to inhibit proliferation, sensitize cells to apoptosis, and modulate signaling pathways highlights its potential for overcoming drug resistance in cancer therapy.

Safety and efficacy of a novel anti-CD19 chimeric antigen receptor T cell product targeting a membrane-proximal domain of CD19 with fast on- and off-rates against non-Hodgkin lymphoma: a first-in-human study.

BACKGROUND: Commercial anti-CD19 chimeric antigen receptor T-cell therapies (CART19) are efficacious against advanced B-cell non-Hodgkin lymphoma (NHL); however, most patients ultimately relapse. Several mechanisms contribute to this failure, including CD19-negative escape and CAR T dysfunction. All four commercial CART19 products utilize the FMC63 single-chain variable fragment (scFv) specific to a CD19 membrane-distal epitope and characterized by slow association (on) and dissociation (off) rates. We hypothesized that a novel anti-CD19 scFv that engages an alternative CD19 membrane-proximal epitope independent of FMC63 and that is characterized by faster on- and off-rates could mitigate CART19 failure and improve clinical efficacy. METHODS: We developed an autologous CART19 product with 4-1BB co-stimulation using a novel humanized chicken antibody (h1218). This antibody is specific to a membrane-proximal CD19 epitope and harbors faster on/off rates compared to FMC63. We tested h1218-CART19 in vitro and in vivo using FMC63-CART19-resistant models. We conducted a first-in-human multi-center phase I clinical trial to test AT101 (clinical-grade h1218-CART19) in patients with relapsed or refractory (r/r) NHL. RESULTS: Preclinically, h1218- but not FMC63-CART19 were able to effectively eradicate lymphomas expressing CD19 point mutations (L174V and R163L) or co-expressing FMC63-CAR19 as found in patients relapsing after FMC63-CART19. Furthermore, h1218-CART19 exhibited enhanced killing of B-cell malignancies in vitro and in vivo compared with FMC63-CART19. Mechanistically, we found that h1218-CART19 had reduced activation-induced cell death (AICD) and enhanced expansion compared to FMC63-CART19 owing to faster on- and off-rates. Based on these preclinical results, we performed a phase I dose-escalation trial, testing three dose levels (DL) of AT101 (the GMP version of h1218) using a 3 + 3 design. In 12 treated patients (7 DLBCL, 3 FL, 1 MCL, and 1 MZL), AT101 showed a promising safety profile with 8.3% grade 3 CRS (n = 1) and 8.3% grade 4 ICANS (n = 1). In the whole cohort, the overall response rate was 91.7%, with a complete response rate of 75.0%, which improved to 100% in DL-2 and -3. AT101 expansion correlates with CR and B-cell aplasia. CONCLUSIONS: We developed a novel, safe, and potent CART19 product that recognizes a membrane-proximal domain of CD19 with fast on- and off-rates and showed significant efficacy and promising safety in patients with relapsed B-cell NHL. TRIAL REGISTRATION: NCT05338931; Date: 2022-04-01.

Anticancer Effect of Gallic Acid on Acidity-Induced Invasion of MCF7 Breast Cancer Cells.

The acidic tumor environment has emerged as a crucial factor influencing the metastatic potential of cancer. We investigated the effect of an acidic environment on the acquisition of metastatic properties in MCF7 breast cancer cells and explored the inhibitory effects of gallic acid. Prolonged exposure to acidic culture conditions (over 12 weeks at pH 6.4) induced the acquisition of migratory and invasive properties in MCF7 cells, accompanied by increased expression of Matrix Metalloproteinase 2 and 9 (MMP2 and MMP9, respectively), together with alterations in E-cadherin, vimentin, and epithelial-to-mesenchymal transition markers. Gallic acid effectively inhibited the survival of acidity-adapted MCF7 (MCF7-6.4/12w) cells at high concentrations (>30 µM) and reduced metastatic characteristics induced by acidic conditions at low concentration ranges (5-20 µM). Moreover, gallic acid suppressed the PI3K/Akt pathway and the nuclear accumulation of ß-catenin, which were elevated in MCF7-6.4/12w cells. These findings highlight the potential of gallic acid as a promising therapeutic agent for metastatic traits in breast cancer cells under acidic conditions.

Gastrointestinal AA Amyloidosis following Recurrent SARS-CoV-2 Infection: A Case Report.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been associated with the overproduction of serum amyloid A protein, resulting in systemic AA amyloidosis. In this report, we describe a case of gastrointestinal (GI) AA amyloidosis following SARS-CoV-2 infection. A 75-year-old male presented to the emergency department with upper abdominal pain 6 weeks post kidney transplantation. He had a history of SARS-CoV-2 infection 4 weeks prior. On day 7 of hospitalization, while receiving conservative management, the patient developed symptoms of cough and fever, leading to a diagnosis of SARS-CoV-2 reinfection. The patient's abdominal pain persisted, and hematochezia developed on day 30 of hospitalization. Esophagogastroduodenoscopy and colonoscopy revealed multiple ulcers in the stomach and colon, with histologic findings revealing the presence of amyloid A. The patient was managed conservatively and was also given remdesivir for the SARS-CoV-2 infection. His clinical symptoms subsequently improved, and endoscopic findings demonstrated improvement in multiple gastric ulcers. GI amyloidosis may be a subacute complication following SARS-CoV-2 infection in immunocompromised patients.

Molecular Basis of Resveratrol-Induced Resensitization of Acquired Drug-Resistant Cancer Cells.

Multidrug resistance (MDR) to anticancer drugs remains a serious obstacle to the success of cancer chemotherapy. Resveratrol, a polyphenol, present in natural products exerts anticancer activity and acts as a potential MDR inhibitor in various drug-resistant cancer cells. In the process of resensitization of drug-resistant cancer cells, resveratrol has been shown to interfere with ABC transporters and drug-metabolizing enzymes, increase DNA damage, inhibit cell cycle progression, and induce apoptosis and autophagy, as well as prevent the induction of epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). This review summarizes the mechanisms by which resveratrol counteracts MDR in acquired drug-resistant cancer cell lines and provides a critical basis for understanding the regulation of MDR as well as the development of MDR-inhibiting drugs.

Extracellular Acidity-mediated Expression of cPLA2γ Confers Resistance in Gastric Cancer Cells.

BACKGROUND/AIM: Extracellular acidity, a characteristic of solid tumors, has been proposed to be a critical factor for aggravating tumor malignancy and conferring resistance to therapeutics. Recently, acidity has been implicated in inflammatory responses, which are mediated through active lipid metabolites in various human tissues. In the present study, we investigated whether acidity can affect lipid-mediated signaling, and found that phospholipase A2 (PLA2) activity increased at acidic pH in SNU601 and AGS gastric carcinoma cell lines. MATERIALS AND METHODS: To identify the PLA2 isoform that is responsible for the acidity-induced activity, we assessed mRNA levels of cPLA2 isotypes through real-time qPCR, and protein levels through immunoblot assay in cells cultured in acidic medium. RESULTS: It was found that acidic pH conditions markedly elevated the PLA2γ expression. A gene interference study using specific siRNA of cPLA2γ suggested that expression of cPLA2γ in acidic culture conditions may be associated with protection of cancer cells in acidic environment, as shown by cell viability and clonogenic assays. In addition, expression of cPLA2γ appeared to confer cell resistance to anticancer drugs under acidic pH conditions. CONCLUSION: Acidity-induced cPLA2γ expression may exert protective effects by imparting resistance to the gastric cancer cells under acidic environment.

Increasing use of therapeutic apheresis as a liver-saving modality.

INTRODUCTION: Therapeutic plasma exchange (TPE) is used for temporary support of liver function in patients presenting with early graft dysfunction after liver transplantation (LT) or liver surgery. We analyzed the effect of therapeutic apheresis on patients with liver disease. METHODS: Between January 2011 and August 2016, 93 apheresis procedures were performed for 26 patients at our institution. Anti-ABO isoagglutination immunoglobulin (Ig) M titer was checked using a type A and type B 3% red blood cell (RBC) suspension in saline with two-fold serial dilutions of patient serum. Anti-ABO isoagglutination IgG titer was checked by a type A and B 0.8% RBC suspension using a low-ionic strength/Coombs card. RESULTS: ABO-incompatible (ABOi) LT was the most common (n=10, 38.5%) indication for apheresis; early graft dysfunction after LT (n=8, 30.7%) was the second most common. Median initial IgM and IgG anti-ABO titers for ABOi LT recipients were 1:16 (range, 1:8-1:128) and 1:48 (range, 1:8-1:2048). We performed preoperative TPE in 10 recipients (median number of sessions, 1.5; range, 1-11). Among patients with early graft dysfunction, those who underwent living donor LT had better survival (4/4; 100%) than those who underwent nonliving donor LT (0/3; 0%). Patients who underwent living donor LT first and then additional LT also survived after three TPE sessions. CONCLUSION: Therapeutic apheresis is associated with a good survival rate and is essential for liver support in patients with early graft dysfunction after LT or posthepatectomy liver failure and during preparation for ABOi LT.

ALK-rearranged adenocarcinoma with extensive mucin production can mimic mucinous adenocarcinoma: clinicopathological analysis and comprehensive histological comparison with KRAS-mutated mucinous adenocarcinoma.

We aimed to investigate clinicopathological features and histology of ALK-rearranged adenocarcinomas with extensive mucin production (AEM) that mimic mucinous adenocarcinoma (MA). Retrospectively, 12 cases of AEM and 25 cases of MA harbouring KRAS mutation were retrieved. The clinicopathological profile and detailed histological features were analysed and compared based on the ALK and KRAS status. AEMs occurred in younger patients (p = 0.044) and were characterised by floating tubulopapillary pattern (p < 0.001), prominent nucleolus (p < 0.001), and apical cytoplasmic snouts (p < 0.001). In contrast, KRAS-mutated MAs lacked ALK-specific histological patterns (p < 0.05). Instead, tumour-infiltrating leukocytes (p = 0.018) and smooth cytoplasmic borders (p < 0.001) with vesicular nuclei (p = 0.004) were prominent in KRAS-mutated MAs. AEMs demonstrated characteristic tubulopapillary pattern and apical snouts, which were distinguishing features from MAs with KRAS mutation. Apical snouts can be a useful histological surrogate for ALK rearrangement in the pulmonary adenocarcinomas showing extensive mucin that mimic MA.

Black Raspberry Extract Increased Circulating Endothelial Progenitor Cells and Improved Arterial Stiffness in Patients with Metabolic Syndrome: A Randomized Controlled Trial.

Administration of black raspberry (Rubus occidentalis) is known to improve vascular endothelial function in patients at a high risk for cardiovascular (CV) disease. We investigated short-term effects of black raspberry on circulating endothelial progenitor cells (EPCs) and arterial stiffness in patients with metabolic syndrome. Patients with metabolic syndrome (n = 51) were prospectively randomized into the black raspberry group (n = 26, 750 mg/day) and placebo group (n = 25) during the 12-week follow-up. Central blood pressure, augmentation index, and EPCs, such as CD34/KDR(+), CD34/CD117(+), and CD34/CD133(+), were measured at baseline and at 12-week follow-up. Radial augmentation indexes were significantly decreased in the black raspberry group compared to the placebo group (-5% ± 10% vs. 3% ± 14%, P < .05). CD34/CD133(+) cells at 12-week follow-up were significantly higher in the black raspberry group compared to the placebo group (19 ± 109/µL vs. -28 ± 57/µL, P < .05). Decreases from the baseline in interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were significantly greater in the black raspberry group compared to the placebo group (-0.5 ± 1.4 pg/mL vs. -0.1 ± 1.1 pg/mL, P < .05 and -5.4 ± 4.5 pg/mL vs. -0.8 ± 4.0 pg/mL, P < .05, respectively). Increases from the baseline in adiponectin levels (2.9 ± 2.1 µg/mL vs. -0.2 ± 2.5 µg/mL, P < .05) were significant in the black raspberry group. The use of black raspberry significantly lowered the augmentation index and increased circulating EPCs, thereby improving CV risks in patients with metabolic syndrome during the 12-week follow-up.

Effects of Rubus occidentalis extract on blood pressure in patients with prehypertension: Randomized, double-blinded, placebo-controlled clinical trial.

OBJECTIVE: Black raspberry (Rubus occidentalis) is known for improving vascular function. However, there has been no study evaluating its effects on 24-h systolic and diastolic blood pressure in prehypertensive patients. The aim of this study was to examine those effects. METHODS: Patients with prehypertension (N = 45) were prospectively randomized into a moderate-dose black raspberry group (n = 15, 1500 mg/d), a high-dose black raspberry group (n = 15, 2500 mg/d), or a placebo group (n = 15) during an 8-wk follow-up period. Raspberries were consumed in the form of a dried powder extract that was fashioned into capsules. The capsules contained 187.5 and 312.5 mg of raspberry powder, which was equivalent to 1500 and 2500 mg raspberries. Ambulatory 24-h blood pressure (BP); central BP; pulse-wave velocity; abdominal visceral fat; serum renin; angiotensin-converting enzyme; and inflammatory cytokines such as interleukin-6, tumor necrosis factor-α, C-reactive protein, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and plasminogen activator inhibitor-1 were measured at baseline and at 8-wk follow-up. RESULTS: High-dose black raspberry significantly reduced 24-h systolic blood pressure (SBP; 3.3 ± 10 mm Hg versus -6.7 ± 11.8 mm Hg; P < 0.05) and nighttime SBP (5.4 ± 10.6 mm Hg versus -4.5 ± 11.3 mm Hg; P < 0.05) compared with controls during the 8-wk follow-up. Black raspberry powder did not produce any significant changes in most of the parameters other than BP. CONCLUSION: The use of black raspberry significantly lowered 24-h BP in prehypertensive patients during the 8-wk follow-up. Black raspberry used as a dietary supplement could be beneficial in reducing SBP in prehypertensive patients.

Melanoma antigen gene family A as a molecular marker of gastric and colorectal cancers.

The present study aimed to evaluate the role of melanoma antigen family A (MAGEA) in gastric and colorectal cancer cell lines and clinical tissue samples. we used 10 gastric and 9 colorectal cancer cell lines, 20 early-stage and 21 advanced-stage gastric cancer tissues, 20 colon adenomas and 19 colorectal cancer tissues. Real-time RT-PCR assay was used for the determination of MAGEA mRNA levels. Western blot analysis and immunohistochemistry were used for the determination of MAGEA protein levels in cell lines and tissues, respectively. Gastric and colorectal cancer cell lines showed variable mRNA expression levels of MAGEA. The MAGEA protein was detected in 30% of gastric cancer cell lines and in 22.2% of colorectal cancer cell lines. There was a high correlation between mRNA and protein expression. Regarding the clinical samples, MAGEA expression was noted in 25, 28.6 and 31.6%, respectively in early-stage, advanced-stage gastric cancer tissues and colon adenocarcinoma, but was negative in the adjacent normal tissues of the stomach and colon as well as colon adenoma. These results indicate that MAGEA is involved in the carcinogenesis of gastric and colorectal cancer and, therefore, can be used as a diagnostic marker to predict these cancers.

Histone H4 deacetylation down-regulates catalase gene expression in doxorubicin-resistant AML subline.

We explored if epigenetic mechanisms could be involved in the down-regulated expression of catalase gene (CAT) in the doxorubicin-resistant acute myelogenous leukemia (AML)-2/DX100 cells. Down-regulated CAT expression in AML-2/DX100 cells was completely recovered after treatment of hydrogen peroxide (H(2)O(2)) and histone deacetylase inhibitor, trichostatin A (TSA) but was increased slightly by the treatment of DNA methylation inhibitor, 5-aza-2'-deoxycytidine (5-AdC). Bisulfite-sequencing PCR revealed that a CpG island of CAT was not methylated in AML-2/DX100 cells. Chromatin immunoprecipitation assay confirmed that acetylation of histone H4 in AML-2/DX100 cells significantly decreased as compared with that in AML-2/WT cells, which was significantly increased by TSA more than 5-AdC. Meanwhile, overexpression of other up-regulated peroxidase genes appears to make compensation for decreased H(2)O(2)-scavenging activity for the down-regulated CAT expression in AML-2/DX100 cells. These results suggest that histone H4 deacetylation is responsible for the down-regulated CAT expression in AML-2/DX100 cells, which are well adapted to oxidative stress.

Up-regulation of cyclooxygenase-2-derived prostaglandin E(2) in colon cancer cells resistant to 5-fluorouracil.

PURPOSE: It has been suggested that constitutive up-regulation of cyclooxygenase (COX)-2 is associated with resistance to apoptosis, increased angiogenesis, and increased tumor invasiveness in various cancers including colon cancer. There are many factors involved in the resistance to 5-fluorouracil (5-FU) in colon cancer. However, little is known about the role of COX-2 in acquired resistance to 5-FU in colon cancer. METHODS: Hence we investigated whether COX-2 contribute to acquired resistance to 5-FU in colon cancer cells, using cytotoxicity assay for cell survival, reverse transcription-polymerase chain reaction (RT-PCR) for vascular endothelial growth factor (VEGF), quantitative RT-PCR for COX-1 and COX-2, and enzyme-linked immunosorbent assay for PGE(2). RESULTS: The 5-FU resistant colon cancer cells, SNU-C5/5FUR, showed increased expression of COX-2, prostaglandin E(2) (PGE(2)), and VEGF, compared to its parental cell (SNU-C5). By treatment with meloxicam, the expression of PGE(2) and VEGF was reduced significantly in the resistant cells, but not in the parent cells. CONCLUSION: These results demonstrate that COX-2 derived PGE(2) is up-regulated and COX-2 inhibitor may have an anti-angiogenic effect in the colon cancer cells resistant to 5-FU.

Lipid raft-dependent death receptor 5 (DR5) expression and activation are critical for ursodeoxycholic acid-induced apoptosis in gastric cancer cells.

Ursodeoxycholic acid (UDCA) is known as a suppressor of cholestatic liver diseases and colorectal cancer development. Here, we demonstrate that UDCA induces apoptosis without necrotic features in SNU601, SNU638, SNU1 and SNU216 human gastric cancer cells, implying its possible use as an effective chemotherapeutic agent in treatment of gastric cancer. UDCA-induced apoptosis was dominantly mediated by an extrinsic pathway dependent on caspase-8, -6 and -3. UDCA increased expression of death receptor 5 [(DR5), also known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2], and this DR appeared to be responsible for UDCA-induced apoptosis, as evidenced by DR5 knockdown. UDCA triggered formation of lipid rafts that played crucial roles in UDCA-induced apoptotic actions. Lipid rafts were required not only for provision of a proper site for DR5 action but also for mediation of DR5 expression. In addition, reactive oxygen species (ROS) and protein kinase C (PKC) δ appeared to be implicated in UDCA-induced raft-dependent DR5 expression. Our results indicate that UDCA-induced apoptosis is mediated by DR5 expression, which is regulated by the raft formation/ROS production/PKCδ activation pathway and DR5 localization into lipid rafts in gastric cancer cells. Tumor-suppressive activity of UDCA was confirmed in an in vivo system: UDCA (120 mg/kg/day) significantly decreased tumor growth in gastric cancer xenograft mice. Taken together, our results demonstrate that UDCA can be used as a potent chemotherapeutic agent for treatment of gastric cancer.

Impacts of cytosolic phospholipase A2, 15-prostaglandin dehydrogenase, and cyclooxygenase-2 expressions on tumor progression in colorectal cancer.

PURPOSE: In addition to cyclooxygenase-2 (COX-2) which is related to prostaglandin E2 synthesis, other enzymes such as cytosolic phospholipase A2 (cPLA2), microsomal prostaglandin E2 synthase-1 (mPGES-1), and 15-prostaglandin dehydrogenase (15-PGDH) have been suggested to be related to carcinogenesis of colorectal cancer (CRC). The aim of this study was to investigate the roles of cPLA2, COX-2, mPGES-1, and 15-PGDH in tumor progression. MATERIALS AND METHODS: cPLA2, COX-2, mPGES-1, 15-PGDH, and vascular endothelial growth factor (VEGF) expressions were immunohistochemically examined in 89 CRC, and their expressions were compared with each other or clinicopathologic parameters as well as VEGF as tumor progression parameters. RESULTS: cPLA2 was expressed in 54.5%, COX-2 in 80.5%, mPGES-1 in 96.4%, 15-PGDH in 46.1%, and VEGF in 65.9%. The expression of cPLA2 correlated with VEGF expression. COX-2 expression was correlated with the depth of invasion, tumor stage, cPLA2, and VEGF expressions. Moreover, VEGF revealed the highest expression in the tissues positive for both cPLA2 and COX-2. Furthermore, 15-PGDH expression was inversely correlated with VEGF expression. CONCLUSION: The present study demonstrates that cPLA2 and mPGES-1, in addition to COX-2, are constitutively overexpressed, and that 15-PGDH might be attenuated in colorectal cancer. Furthermore, cPLA2 and 15-PGDH as well as COX-2 could have an important role in tumor progression.

Detection of drug transporter expression using a 25-multiplex RT-PCR assay.

Membrane transporters play important roles in mediating chemoresistance and chemosensitivity of tumor cells. Five sets of 5 genes were designed to simultaneously detect drug transporter expression in a single reaction tube using multiplex RT-PCR for 25 genes, including 17 ABC transporters, one non-ABC transporter, 4 SLC transporters, 2 copper transporters and one housekeeping gene. We optimized the multiplex RT-PCR conditions using chemosensitive cancer cells and then validated the system using chemoresistant cancer cells. This reliable multiplex RT-PCR assay can be utilized not only to investigate anticancer drug-resistance mechanisms but also to estimate the efficacy of anticancer chemotherapy in the clinic.

Significance of p-STAT3 expression in human colorectal adenocarcinoma.

To examine the relationship between p-STAT3 and the clinicopathological parameters of colorectal adenocarcinoma (CRA), we initially conducted immunohistochemical (IHC) analyses on formalin-fixed tissues. A total of 127 invasive CRA, 20 colorectal adenomas and 20 normal mucosae were obtained. To clarify the validity of p-STAT3 as determined by the IHC analysis, quantitative real-time PCR was performed on fresh samples from 51 CRA-4 carcinomas in situ, 47 invasive CRA and on 51 normal mucosae. IHC analyses were conducted after formalin fixation from 51 CRA for comparison. The statistically significant difference of immunoreactivity for p-STAT3 between the CRA and adenoma, and between the CRA and normal mucosae was identified. Among the 174 CRA, p-STAT3 immunoreactivity significantly correlated with the T- and clinical stage. Among the 47 invasive CRA, the expression of STAT3 as determined by real-time PCR significantly correlated with tumor size, M stage and clinical stage. The overall findings of the real-time PCR analyses correlated with the findings of the IHC analyses. These findings suggest that p-STAT3 expression has an important role related to the tumorigenesis and tumor progression of CRAs. Moreover, IHC analysis is a reliable and useful modality of assessing the status of p-STAT3 expression in formalin-fixed samples.

Epigenetic mechanisms involved in differential MDR1 mRNA expression between gastric and colon cancer cell lines and rationales for clinical chemotherapy.

BACKGROUND: The membrane transporters such as P-glycoprotein (Pgp), the MDR1 gene product, are one of causes of treatment failure in cancer patients. In this study, the epigenetic mechanisms involved in differential MDR1 mRNA expression were compared between 10 gastric and 9 colon cancer cell lines. METHODS: The MDR1 mRNA levels were determined using PCR and real-time PCR assays after reverse transcription. Cytotoxicity was performed using the MTT assay. Methylation status was explored by quantification PCR-based methylation and bisulfite DNA sequencing analyses. RESULTS: The MDR1 mRNA levels obtained by 35 cycles of RT-PCR in gastric cancer cells were just comparable to those obtained by 22 cycles of RT-PCR in colon cancer cells. Real-time RT-PCR analysis revealed that MDR1 mRNA was not detected in the 10 gastric cancer cell lines but variable MDR1 mRNA levels in 7 of 9 colon cancer cell lines except the SNU-C5 and HT-29 cells. MTT assay showed that Pgp inhibitors such as cyclosporine A, verapamil and PSC833 sensitized Colo320HSR (colon, highest MDR1 expression) but not SNU-668 (gastric, highest) and SNU-C5 (gastric, no expression) to paclitaxel. Quantification PCR-based methylation analysis revealed that 90% of gastric cancer cells, and 33% of colon cancer cells were methylated, which were completely matched with the results obtained by bisulfite DNA sequencing analysis. 5-aza-2'-deoxcytidine (5AC, a DNA methyltransferase inhibitor) increased the MDR1 mRNA levels in 60% of gastric cells, and in 11% of colon cancer cells. Trichostatin A (TSA, histone deacetylase inhibitor) increased the MDR1 mRNA levels in 70% of gastric cancer cells and 55% of colon cancer cells. The combined treatment of 5AC with TSA increased the MDR1 mRNA levels additively in 20% of gastric cancer cells, but synergistically in 40% of gastric and 11% of colon cancer cells. CONCLUSION: These results indicate that the MDR1 mRNA levels in gastric cancer cells are significantly lower than those in colon cancer cells, which is at least in part due to different epigenetic regulations such as DNA methylation and/or histone deacetylation. These results can provide a better understanding of the efficacy of combined chemotherapy as well as their oral bioavailability.

Hyperthermia switches glucose depletion-induced necrosis to apoptosis in A549 lung adenocarcinoma cells.

Both cellular and clinical studies have shown that hyperthermia is one of the most potent sensitizers for the action of ionizing radiation. Although hyperthermic improvement in clinical outcome is suggested to be linked to its ability to induce cell cycle arrest and apoptosis, and to activate the immune system and to cause increases in blood flow and tumor oxygenation, the mechanism behind this is still unclear. Previously, we demonstrated that glucose deprivation (GD), a common characteristic of the tumor microenvironment, induced necrosis, which is implicated in tumor progression and aggressiveness, through the production of reactive oxygen species (ROS) in A549 lung carcinoma cells. We examined the effects of heat shock on ROS production and necrosis in response to GD. Here we show that mild, but not harsh, heat shock prevented GD-induced necrosis and switched the cell death mode to apoptosis in A549 cells through the ERK1/2 pathway that could suppress GD-induced CuZnSOD release and ROS production. These results demonstrate that contrary to severe heat shock, mild heat shock has the ability to decrease oxidative stress in cells, thereby causing the cell death mode switch from tumor promoting necrosis to tumor suppressive apoptosis, which may contribute to its anti-neoplastic activities.

Prognostic significance of cyclooxygenase-2 expression and nuclear p53 accumulation in patients with colorectal cancer.

BACKGROUND: Cyclooxygenase (COX)-2 is believed to be an important enzyme related to the pathogenesis of colorectal cancer (CRC). p53 has been reported to be a negative regulator of COX-2 expression in in vitro studies. The aim of this study was to investigate COX-2 expression and its relationship with nuclear p53 accumulation and their prognostic significance in CRC. METHODS: COX-2 expression and nuclear p53 accumulation were examined by immunohistochemistry in 231 sporadic CRCs. Their prognostic significance and interrelationship were statistically evaluated. RESULTS: We found 42.4% of the 231 cases of CRCs with positive COX-2 expression. Nuclear p53 accumulation was observed in 46.8% of cases. There was no significant correlation between COX-2 expression and nuclear p53 accumulation. COX-2 expression had no correlation with patient survival, whereas nuclear p53 accumulation was significantly correlated with poor patient survival on univariate and multivariate analysis. CONCLUSIONS: These results suggest that COX-2 expression does not play a role in the prognosis of CRC and COX-2 expression is not affected by the status of nuclear p53 accumulation in CRC. In addition, our findings support that nuclear p53 accumulation may be a useful prognostic marker for patients with CRC.