Curcumin inhibits the growth and invasion of gastric cancer by regulating long noncoding RNA AC022424.2.

BACKGROUND: Gastric cancer, characterized by a multifactorial etiology and high heterogeneity, continues to confound researchers in terms of its pathogenesis. Curcumin, a natural anticancer agent, exhibits therapeutic promise in gastric cancer. Its effects include promoting cell apoptosis, curtailing tumor angiogenesis, and enhancing sensitivity to radiation and chemotherapy. Long noncoding RNAs (lncRNAs) have garnered significant attention as biomarkers for early screening, diagnosis, treatment, and drug response because of their remarkable specificity and sensitivity. Recent investigations have revealed an association between aberrant lncRNA expression and early diagnosis, clinical staging, metastasis, drug sensitivity, and prognosis in gastric cancer. A profound understanding of the intricate mechanisms through which lncRNAs influence gastric cancer development can provide novel insights for precision treatment and tailored management of patients with gastric cancer. This study aimed to unravel the potential of curcumin in suppressing the malignant behavior of gastric cancer cells by upregulating specific lncRNAs and modulating gastric cancer onset and progression. AIM: To identify lncRNAs associated with curcumin treatment and investigate the role of lncRNA AC022424.2 in the effects of curcumin on gastric cancer cell apoptosis, proliferation, and invasion. Furthermore, these findings were validated in clinical samples. METHODS: The study employed CCK-8 assays to assess the impact of curcumin on gastric cancer cell proliferation, flow cytometry to investigate its effects on apoptosis, and scratch and Transwell assays to evaluate its influence on the migration and invasion of BGC-823 and MGC-803 cells. Western blotting was used to gauge changes in the protein expression levels of CDK6, CDK4, Bax, Bcl-2, caspase-3, P65, and the PI3K/Akt/mTOR pathway in gastric cancer cell lines after curcumin treatment. Differential expression of lncRNAs before and after curcumin treatment was assessed using lncRNA sequencing and validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in BGC-823 and MGC-803 cells. AC022424.2-1 knockdown BGC-823 and MGC-803 cells were generated to scrutinize the impact of lncRNA AC022424.2 on apoptosis, proliferation, migration, and invasion of gastric cancer cells. Western blotting was performed to ascertain changes in the expression of proteins implicated in the PI3K/Akt/mTOR and NF-κB signaling pathways. RT-PCR was employed to measure lncRNA AC022424.2 expression in clinical gastric cancer tissues and to correlate its expression with clinical pathological characteristics. RESULTS: Curcumin induced apoptosis and hindered proliferation, migration, and invasion of gastric cancer cells in a dose- and time-dependent manner. LncRNA AC022424.2 was upregulated after curcumin treatment, and its knockdown enhanced cancer cell aggressiveness. LncRNA AC022424.2 may have affected cancer cells via the PI3K/Akt/mTOR and NF-κB signaling pathways. LncRNA AC022424.2 downregulation was correlated with lymph node metastasis, making it a potential diagnostic and prognostic marker. CONCLUSION: Curcumin has potential anticancer effects on gastric cancer cells by regulating lncRNA AC022424.2. This lncRNA plays a significant role in cancer cell behavior and may have clinical implications in diagnosis and prognosis evaluation. The results of this study enhance our understanding of gastric cancer development and precision treatment.

The Role of IL-37 and IL-38 in Colorectal Cancer.

Colorectal cancer (CRC) is a major killer. Dysregulation of IL-37 and IL-38, both anti-inflammatory cytokines, is observed in auto-immune diseases. The precise regulatory mechanisms of IL-37/IL-38 during the development of CRC remains unclear, but chronic intestinal inflammation is involved in the carcinogenesis of CRC. Constitutive production of colonic IL-37 and IL-38 is substantially reduced in CRC, consistent with an inverse correlation with CRC differentiation. Reduced colonic IL-37 and IL-38 is relating to CRC invasion and distant metastasis, suggesting a protective role for IL-38 within the tumor micro-environment. IL-38 is reduced in right-sided CRC compared to left-sided CRC, which is in line with multiple risk factors for right-sided CRC, including the embryonic development of the colon, and genetic differences in CRC between these two sides. Finally, colonic IL-37 and tumor associated neutrophils (TAN) seem to be independent biomarkers of prognostic value, whereas colonic IL-38 seems to be a reliable and independent biomarker in predicting the 5-year survival post-surgery in CRC. However, there is room for improvement in available studies, including the extension of these studies to different regions/countries incorporating different races, evaluation of the role of multi-drug resistance, and different subsets of CRC. It would be useful to determine the kinetics of circulating IL-38 and its relationship with drug resistance/targeted therapy. The measurement of colonic IL-38 at the molecular and cellular level is required to explore the contribution of IL-38 pathways during the development of CRC. These approaches could provide insight for the development of personalized medicine.

Evaluating Terminator Strength Based on Differentiating Effects on Transcription and Translation.

Transcription terminators play a role in terminating the progress of gene transcription, and are thus essential elements in the gene circuit. Terminators have two main functions: terminating gene transcription and improving the stability of gene transcripts during translation. We therefore considered the detailed characteristics of terminators in relation to their different roles in gene transcription and translation, including transcription shut-down degree (α) and upstream mRNA protection capacity (ß), and apparent termination efficiency (η) reflecting the overall regulatory effect of the terminator. Based on a dual-reporter gene system, we constructed three terminator-probe plasmids to investigate each characteristic in Escherichia coli. According to multiple regression analysis, the transcription shut-down degree and the upstream mRNA protection capacity contributed almost equally to the apparent termination efficiency. Sequence analysis of 12 terminators demonstrated that the terminator sequence was dominated by GC bases, and that a high ratio of GC bases in the stem structure of terminators might be associated with a high degree of transcription shut-down. This comprehensive characterization of terminators furthers our understanding of the role of terminators in gene expression and provides a guide for synthetic terminator design.

Circ-0001313/miRNA-510-5p/AKT2 axis promotes the development and progression of colon cancer.

Circular RNAs (circRNAs) have recently emerged as novel and potentially promising therapeutic targets in a serious of cancers. However, the expression pattern and biological function of circRNAs in colon cancer remain largely elusive. This study firstly analyzed circRNA microarray of colon cancer and selected circ-0001313 as the study object. We aim to comprehensively investigate the expression pattern and biological function of circ-0001313 in the progression of colon cancer. Relative levels of circ-0001313 and miRNA-510-5p in colon cancer tissues and cell lines were determined with qRT-PCR. The binding relationship between miRNA-510-5p to circ-0001313 and AKT2 was predicted by bioinformatics analyses and further confirmed by dual-luciferase reporter gene assay. Regulatory effects of circ-0001313/miRNA-510-5p/AKT2 axis on colon cancer cells were evaluated by EdU assay and flow cytometry. Consistent with the microarray analysis, circ-0001313 was highly expressed in colon cancer tissues and cell lines. Knockdown of circ-0001313 attenuated proliferative ability, but induced apoptosis of colon cancer cells. Furthermore, we confirmed that circ-0001313 competitively bound to miRNA-510-5p, thus upregulating its target gene AKT2. Moreover, western blot analyses revealed that circ-0001313 also affects the expression of Bcl-2 family proteins and the activation of PI3K/Akt signaling pathway. In conclusion, our study revealed that circ-0001313 regulates the pathogenesis of colon cancer by sponging miRNA-510-5p to upregulate AKT2 expression.

LINC00961 inhibits the migration and invasion of colon cancer cells by sponging miR-223-3p and targeting SOX11.

Long noncoding RNAs play essential roles in colon cancer tumorigenesis. This study aimed to explore the potential function and molecular mechanisms of LINC00961 in colon cancer. qPCR results showed that LINC00961 was downregulated in colon cancer cells and tissues. Functional assays demonstrated that LINC00961 suppressed the migration and invasion of colon cancer cells in vitro. LINC00961 functioned as an endogenous sponge for miR-223-3p in colon cancer cells. SOX11 was confirmed as a target gene of miR-223-3p. The effect of miR-223-3p on colon cancer cells was then investigated. MiR-223-3p inhibition enhanced their migration and invasion. The effect of SOX11 on colon cancer cells was studied. SOX11 overexpression inhibited the invasion of colon cancer cells. LINC00961 acted as an anti-oncogene and upregulated SOX11 expression by functioning as a miR-223-3p sponge. This research revealed the molecular mechanism of LINC00961 in colon cancer. LINC00961 might act as a potential diagnostic biomarker and therapeutic target for further clinical treatments.

The involvement of miR-150/ß-catenin axis in colorectal cancer progression.

Colorectal cancer remains as a serious global cause of morbidity and mortality. The current therapies for colorectal cancer treatment are still unsatisfactory and thus, identification of novel targets is an urgent requisite. Recent evidence has reported miRNAs are closely correlated with colorectal cancer development. miR-150 has been identified in tumor progression in various cancers. Nevertheless, its roles in colorectal cancer remain poorly known. In our study, a decreased miR-150 expression in colorectal cancer tissues and cells was observed. Meanwhile, we reported a negative correlation between miR-150 and ß-catenin in colorectal cancer. ß-catenin can participate in the physiological mechanism of many types of cancers. Then, miR-150 was overexpression in SW480 and HT-29 cells and it was show that miR-150 repressed SW480 and HT-29 cell viability, proliferation and colony formation capacity. Moreover, colorectal cancer cell progression was triggered by the inhibition of miR-150 via negatively regulating ß-catenin. Subsequently, the direct binding correlation between miR-150 and ß-catenin was demonstrated. ß-catenin, c-myc and CyclinD1 level was significantly restrained by the up-regulation of miR-150 in SW480 and HT-29 cells. Finally, it was proved that miR-150 depressed colorectal cancer growth through modulating ß-catenin in vivo. Overall, it was implied that miR-150 could inhibit colorectal cancer progression and serve as a tumor suppressor via inactivating ß-catenin pathway.

NEAT1 promotes colon cancer progression through sponging miR-495-3p and activating CDK6 in vitro and in vivo.

Recently, increasing evidence has indicated lncRNAs are powerful regulators in the progression of multiple tumors. Dysregulation of lncRNA NEAT1 has been recognized in many cancer types. Meanwhile, the studies on NEAT1 function have suggested that NEAT1 can serve as a crucial oncogene. Nevertheless, the investigation of NEAT1 in colon cancer is still few. In our study, the function of NEAT1 was studied in colon cancer. As we observed, NEAT1 level was obviously elevated in colon cancer cells. Then, HCT-116 and SW620 cells were stably infected with shRNA-NEAT1 for 48 hr. As exhibited, silence of NEAT1 could greatly repress colon cancer cell progression. Apoptosis of colon cancer cells was triggered and the cell cycle progression was remarkably inhibited by downregulation of NEAT1. Interestingly, as exhibited, miR-495-3p was obviously decreased in colon cancer cells and it significantly suppressed colon cancer progression. Subsequently, miR-495-3p was predicted as a target of NEAT1. CDK6 was speculated as the target of miR-495-3p and miR-495-3p modulated its expression negatively. Finally, it was indicated that NEAT1 promoted colon cancer development through modulating miR-495-3p and CDK6 in vivo. Taken these together, we reported that NEAT1 could sponge miR-495-3p to contribute to colon cancer progression through activating CDK6.

Health outcomes in offspring of mother with breast implants: A protocol of systematic review and meta-analysis.

BACKGROUND: An increasing number of women undergo breast augmentation at their reproductive age. The most existing evidence focuses on the impact of breast implant on the index women's health and breastfeeding after they give birth to a child. No previous systematic review has investigated the association between breast implant in mother and health outcomes in offspring. In this study, we aimed to conduct a systematic review and meta-analysis to evaluate the influence of breast implant on offspring's health outcomes. METHODS: A comprehensive search strategy will be conducted including the following databases: MEDLINE (via PubMed), Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wan Fang Data. The World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) will be searched as well for retrieving the ongoing studies. The cohort study and case-control study will be considered as eligible study if investigating the impact of breast implant in mother on health outcomes in offspring. The risk of bias of included studies will be appraised by the Newcastle-Ottawa scale. RESULTS: The results of this study will be presented in the full-text of the systematic review. CONCLUSION: This systematic review and meta-analysis will infer a conclusion on the association between breast implant in mother and health outcomes in offspring, and the quality of existing evidence.PROSPERO registration number: CRD42019121221.

Identification of LINC01234 and MIR210HG as novel prognostic signature for colorectal adenocarcinoma.

This study aimed to identify potential biomarkers and the therapeutic targets for colorectal adenocarcinoma by systematically evaluate a large scale of long noncoding RNAs (lncRNAs) expression data from TCGA. The algorithm t-distributed stochastic neighbor embedding and hierarchical clustering were utilized to group the samples into three clusters that showed a different prognosis. To identify the relationship between the clustered groups and different histoclinical features, different statistical methods were used. The functions of LINC01234 and MIR210HG were investigated with the help of the public database. The results showed that the expression levels of lncRNAs were able to distinguish the tumor samples from the normal tissues and in further they were able to predict the prognosis of the patients. We proposed two potential lncRNAs, which might serve as a biomarker or therapeutic targets. LINC01234 can be a good biomarker. In contrast, MIR210HG participated in the progression of colorectal adenocarcinoma by regulating hypoxia. It might function through an lncRNA-microRNA-messenger RNA regulatory network with MIR210 and RASSF7.

Comparative efficacy of non-pharmacological adjuvant therapies for quality of life in the patients with breast cancer receiving chemo- or radio-therapy: A protocol for systematic review and Bayesian network meta-analysis.

BACKGROUND: Breast cancer is the most frequently diagnosed cancer in women worldwide. When treated by chemotherapy and/or radiotherapy, there are various non-pharmacological adjuvant therapies (NPATs) recommended for helping the patients with breast cancer alleviate multiple side effects induced by chemotherapy and/or radiotherapy and improve quality of life (QoL). However, the existing evidence does not suggest the therapy with the best effectiveness among a variety of NPATs. This study is to compare the effectiveness of different NPATs on QoL in the patients with breast cancer using Bayesian network meta-analysis (NMA). METHODS AND ANALYSIS: We will conduct a comprehensive search strategy in the relevant databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, World Health Organization (WHO), International Clinical Trials Registry Platform (ICTRP) search portal (http://apps.who.int/trialsearch/Default.aspx), Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wan Fang Data). The random or quasi-random controlled trails that compare different NPATs in patient with breast cancer who received the chemotherapy and/or radiotherapy will be included. We only focus on the outcome of QoL which can be assessed by a series of tools. The risk of bias for included studies will be appraised using the Cochrane Collaboration's tool for assessing risk of bias. The standard pairwise meta-analysis and a Bayesian NMA will be conducted. ETHICS AND DISSEMINATION: Ethical approval and patient consent are not required since this is an NMA based on published studies. We will submit our NMA to a peer-reviewed journal for publication. PROSPERO REGISTRATION NUMBER: CRD42017078143.

Chaperonin containing TCP-1 subunit 3 is critical for gastric cancer growth.

BACKGROUND: Members of eukaryotic chaperonin family are essential for cell survival. Dysregulation of Chaperonin containing TCP-1 subunit 3 (CCT3) has been implicated in the development of several types of cancers. However, the role of CCT3 in the development of gastric cancer has yet to be determined. METHODS: The expression patterns of CCT3 in the surgical specimens from 26 gastric cancer patients were evaluated using immunohistochemistry methods. To study the possible roles of CCT3 in the growth and survival of gastric cancer cells, RNA interference was used to knockdown CCT3 expression in gastric cancer cell lines BGC-823 and MGC-803. The effects of CCT3 knockdown on cancer cell proliferation, apoptosis and in vivo growth were examined. Finally, gene expression changes related to CCT3 knockdown were studied using gene array analysis and western blotting. RESULTS: Higher level of CCT3 expression was detected in the gastric cancer tissue compared to adjacent non-cancerous epithelium. Knockdown of CCT3 inhibited proliferation and colony formation while promoted apoptosis of gastric cancer cells in vitro. Gastric cancer cells exhibited lower growth potential in nude mice when CCT3 expression was suppressed. Gene expression analysis showed that CCT3 knockdown was associated with down-regulation of mitogen-activated protein kinase kinase kinase 7, cell division cycle 42, cyclin D3 and up-regulation of cyclin-dependent kinase 2 and 6. CONCLUSION: Our results suggested that CCT3 played a critical role in gastric cancer growth and survival. Further studies on the mechanisms of CCT3 function is mandated to develop novel cancer treatment targeting CCT3.

Quality appraisal of clinical practice guidelines on pancreatic cancer: a PRISMA-compliant article.

Clinical practice guidelines (CPGs) play an important role in health care. The guideline development process should be precise and rigorous to ensure that the results are reproducible and not vague. To determine the quality of guidelines, the Appraisal of Guidelines and Research and Evaluation (AGREE) instrument was developed and introduced. The objective of this study is to assess the methodological quality of CPGs on pancreatic cancer. Five databases (included MEDLINE and EMBASE) and guideline websites were searched till April, 2014. The methodological quality of the guidelines was assessed by 4 authors independently using the AGREE II instrument. From 2526 citations, 21 relevant guidelines were included. The overall agreement among reviewers was moderate (intraclass correlation coefficient = 0.86, 95% confidence interval 0.64-0.96). The mean scores were moderate for the domains "scope and purpose" and "clarity of presentation"; however, they were low for the domains "stakeholder involvement" (31.22), "rigor of development", "applicability", and "editorial independence". These domain scores were lower when compared with international levels. There are 5 (23.81%) guidelines that described the systematic methods for searching. Moreover, only 5 (23.81%) guidelines reported that methodological expertise were included in the guideline developing teams. The quality and transparency of the development process and the consistency in the reporting of pancreatic cancer guidelines need to be improved. Many other methodological disadvantages were identified. In the future, pancreatic cancer CPGs should base on the best available evidence rigorously developed and reported. Greater efforts are needed to provide high-quality guidelines that serve as a useful and reliable tool for clinical decision making in this field.

Factors influencing the feasibility of laparoscopy colectomy.

OBJECTIVE: The objective was to review the factors affecting the feasibility of performing successful laparoscopic colectomy. DATA SOURCES: The literatures about the risk factors closely related to the ability to perform laparoscopic colectomy on different surgical diseases of the colon cited in this review were obtained from PubMed published in English from 2006 to 2012. STUDY SELECTION: Original articles regarding the risk factors that affect the ability to perform laparoscopic colectomy were selected. RESULTS: Obesity, diabetes, inflammatory bowel diseases, advanced age, emergency operation, and pelvic anatomy are all important risk factors that increase the risk of developing serious complications such as hemorrhage, anastomotic leak, and skin and soft tissue infections following laparoscopic colectomy. These factors also increase the likelihood of conversion to an open operation. In this study, we reviewed the recent original articles about the relationship of laparoscopic colectomy with these risk factors. We also describe some strategies that limit the likelihood of these complications and the likelihood of conversion to an open operation. CONCLUSIONS: Obesity, diabetes, inflammatory bowel diseases, age, emergency operation, and pelvic anatomy are all important risk factors that increase the risk of either serious complications or conversion to open operation with laparoscopic colectomy. Evaluation of these risk factors preoperatively should influence the decision to perform colectomy using laparoscopic techniques.

Honokiol as a Radiosensitizing Agent for Colorectal cancers.

Radioresistance is a frustrating obstacle for patients with colorectal cancers (CRCs) undergoing radiotherapy. There is an urgent need to find an effective agent to increase the sensitivity of CRCs to radiation. Honokiol, an active compound purified from Magnolia, was found to radiosensitize colorectal cancer cells both in vitro and in vivo. However, the mechanisms control important signaling that enhances radiosensitivity is currently unknown. In this study, we have reviewed important signaling pathways that are closely related to radiosensitization, such as cell cycle arrest, tumor angiogenesis, JAK/STAT3 signaling pathway and Mismatch repair. Studies show that honokiol can interfere with these pathways at different levels. With overall analysis, it may bring light on finding the possible mechanism by which honokiol acts as a radiosensitizing agent for CRCs.

Chromium picolinate supplementation for overweight or obese adults.

BACKGROUND: Obesity is a global public health threat. Chromium picolinate (CrP) is advocated in the medical literature for the reduction of bodyweight, and preparations are sold as slimming aids in the USA and Europe, and on the Internet. OBJECTIVES: To assess the effects of CrP supplementation in overweight or obese people. SEARCH METHODS: We searched The Cochrane Library, MEDLINE, EMBASE, ISI Web of Knowledge, the Chinese Biomedical Literature Database, the China Journal Full text Database and the Chinese Scientific Journals Full text Database (all databases to December 2012), as well as other sources (including databases of ongoing trials, clinical trials registers and reference lists). SELECTION CRITERIA: We included trials if they were randomised controlled trials (RCT) of CrP supplementation in people who were overweight or obese.We excluded studies including children, pregnant women or individuals with serious medical conditions. DATA COLLECTION AND ANALYSIS: Two authors independently screened titles and abstracts for relevance. Screening for inclusion, data extraction and 'Risk of bias'assessment were carried out by one author and checked by a second. We assessed the risk of bias by evaluating the domains selection,performance, attrition, detection and reporting bias. We performed a meta-analysis of included trials using Review Manager 5. MAIN RESULTS: We evaluated nine RCTs involving a total of 622 participants. The RCTs were conducted in the community setting, with interventions mainly delivered by health professionals, and had a short- to medium-term follow up (up to 24 weeks). Three RCTs compared CrPplus resistance or weight training with placebo plus resistance or weight training, the other RCTs compared CrP alone versus placebo.We focused this review on investigating which dose of CrP would prove most effective versus placebo and therefore assessed the results according to CrP dose. However, in order to find out if CrP works in general, we also analysed the effect of all pooled CrP doses versus placebo on body weight only.Across all CrP doses investigated (200 µg, 400 µg, 500 µg, 1000 µg) we noted an effect on body weight in favour of CrP of debatable clinical relevance after 12 to 16 weeks of treatment: mean difference (MD) -1.1 kg (95% CI -1.7 to -0.4); P = 0.001; 392 participants;6 trials; low-quality evidence (GRADE)). No firm evidence and no dose gradient could be established when comparing different doses of CrP with placebo for various weight loss measures (body weight, body mass index, percentage body fat composition, change in waist circumference).Only three studies provided information on adverse events (low-quality evidence (GRADE)). There were two serious adverse events and study dropouts in participants taking 1000 µg CrP, and one serious adverse event in an individual taking 400 µg CrP. Two participants receiving placebo discontinued due to adverse events; one event was reported as serious. No study reported on all-cause mortality,morbidity, health-related quality of life or socioeconomic effects. AUTHORS' CONCLUSIONS: We found no current, reliable evidence to inform firm decisions about the efficacy and safety of CrP supplements in overweight or obese adults.

Honokiol in combination with radiation targets notch signaling to inhibit colon cancer stem cells.

Cancer stem cells are implicated in resistance to ionizing radiation (IR) and chemotherapy. Honokiol, a biphenolic compound has been used in traditional Chinese medicine for treating various ailments. In this study, we determined the ability of honokiol to enhance the sensitivity of colon cancer stem cells to IR. The combination of honokiol and IR suppressed proliferation and colony formation while inducing apoptosis of colon cancer cells in culture. There were also reduced numbers and size of spheroids, which was coupled with reduced expression of cancer stem cell marker protein DCLK1. Flow cytometry studies confirmed that the honokiol-IR combination reduced the number of DCLK1+ cells. In addition, there were reduced levels of activated Notch-1, its ligand Jagged-1, and the downstream target gene Hes-1. Furthermore, expression of components of the Notch-1 activating γ-secretase complex, presenilin 1, nicastrin, Pen2, and APH-1 was also suppressed. On the other hand, the honokiol effects were mitigated when the Notch intracellular domain was expressed. To determine the effect of honokiol-IR combination on tumor growth in vivo, nude mice tumor xenografts were administered honokiol intraperitoneally and exposed to IR. The honokiol-IR combination significantly inhibited tumor xenograft growth. In addition, there were reduced levels of DCLK1 and the Notch signaling-related proteins in the xenograft tissues. Together, these data suggest that honokiol is a potent inhibitor of colon cancer growth that targets the stem cells by inhibiting the γ-secretase complex and the Notch signaling pathway. These studies warrant further clinical evaluation for the combination of honokiol and IR for treating colon cancers.

Honokiol radiosensitizes colorectal cancer cells: enhanced activity in cells with mismatch repair defects.

DNA mismatch repair is required for correcting any mismatches that are created during replication and recombination, and a defective mismatch repair system contributes to DNA damage-induced growth arrest. The colorectal cancer cell line HCT116 is known to have a mutation in the hMLH1 mismatch repair gene resulting in microsatellite instability and defective mismatch repair. Honokiol is a biphenolic compound that has been used in traditional Chinese medicine for treating various ailments including cancer. This study was designed to test the hypothesis that honokiol enhances the radiosensitivity of cancer cells with mismatch repair defect (HCT116) compared with those that are mismatch repair proficient (HCT116-CH3). We first determined that the combination of honokiol and γ-irradiation treatment resulted in dose-dependent inhibition of proliferation and colony formation in both cell lines. However, the effects were more pronounced in HCT116 cells. Similarly, the combination induced higher levels of apoptosis (caspase 3 activation, Bax to Bcl2 ratio) in the HCT116 cells compared with HCT116-CH3 cells. Cell cycle analyses revealed higher levels of dead cells in HCT116 cells. The combination treatment reduced expression of cyclin A1 and D1 and increased phosphorylated p53 in both cell lines, although there were significantly lower amounts of phosphorylated p53 in the HCT116-CH3 cells, suggesting that high levels of hMLH1 reduce radiosensitivity. These data demonstrate that honokiol is highly effective in radiosensitizing colorectal cancer cells, especially those with a mismatch repair defect.