MiR-509-3p is oncogenic, targets the tumor suppressor PHLPP2, and functions as a novel tumor adjacent normal tissue based prognostic biomarker in colorectal cancer.

BACKGROUND: Recently the role of microRNAs has been explored immensely as novel regulators and potential biomarkers in several cancers. MiR-509-3p is one such miRNA that has been observed to show a mixed expression in different cancers, while it's expression and clinical relevance in colorectal cancer (CRC) has not yet been characterized. METHODS: We used quantitative PCR to evaluate the expression of miR-509-3p in fresh-frozen CRC tumor tissues and the corresponding tumor-adjacent normal (NAT) tissues from 103 patients. Subsequently, functional studies were performed to further interpret the role of the miRNA in CRC. RESULTS: MiR-509-3p was found to be overexpressed in CRC tissues in nearly 80% of cases and was associated with an aggressive disease presentation. Notably, a higher expression of the miRNA promoted cell proliferation, migration, and invasion of CRC cells in in vitro and in vivo models. Mechanistically, we confirmed that miR-509-3p directly binds the 3'UTR of the tumor suppressor PHLPP2 and inhibits its expression. Furthermore, within the previous 103 clinical tissue specimens, we observed an overexpression of miR-509-3p within the NAT tissue of patients associated with a poor disease prognosis. Using multivariate analysis, it was observed that the expression of miR-509-3p within the NAT tissue was an independent predictor of prognosis in CRC. At the cellular level, through indirect coculture experiments, miR-509-3p was observed to regulate the proliferative, migratory, and invasive behavior of normal colon cells. CONCLUSION: MiR-509-3p strongly contributes to the development and progression of CRC and can potentially function as a prognostic biomarker in the disease.

CD26 Induces Colorectal Cancer Angiogenesis and Metastasis through CAV1/MMP1 Signaling.

CD26 has been reported as a marker for colorectal cancer stem cells endowed with tumor-initiating properties and capable of colorectal cancer (CRC) metastasis. In this study, we investigated the functional effect of CD26 on CRC angiogenesis and metastasis, and the potential underlying mechanism. The functional effects of CD26 overexpression or repression were determined by a wound healing experiment, and cell migration and invasion assays in vitro and in mouse models. Differentially expressed genes regulated by CD26 were identified by genome-wide mRNA expression array and validated by quantitative PCR. CD26 functionally regulated CRC cell migration and invasion in vitro and angiogenesis and metastasis in vivo. Genome-wide mRNA expression array and qPCR showed that MMP1 was up-regulated in CD26+ subpopulation, and a subsequent experiment demonstrated the regulatory effect of CD26 on MMP1 in CRC cell lines with CD26 repression or overexpression. Furthermore, overexpression of CAV1 abrogated the CD26-regulated MMP1 induction in CRC cell lines. This study demonstrated the functional roles of CD26 in inducing CRC migration, invasion, angiogenesis and metastasis and identified the potential involvement of MMP1 and CAV1 in such process. CD26 is an attractive therapeutic target for combating tumor progression to improve the prognosis of CRC patients.

Overexpression of Pin1 and rho signaling partners correlates with metastatic behavior and poor recurrence-free survival of hepatocellular carcinoma patients.

BACKGROUND: Identification of molecular markers for early detection or prediction of metastasis is crucial for both management of HCC patient postoperative treatment and identify new therapeutic targets to inhibit HCC progression and metastasis. In the current study, we investigated the clinical correlation between Pin1, RhoA and RhoC and their association with HCC metastasis. METHODS: Using a randomized study design of primary HCC samples from 139 patients, we determined messenger RNA expression of Pin1, RhoA and RhoC and their prognostic value. RESULTS: Our findings demonstrated for the first time the clinical correlation of Pin1 in HCC metastasis. Pin1, RhoA and RhoC transcript levels were significantly higher in HCC specimens when compared with the paired adjacent non-tumorous liver. Pin1 overexpression was closely correlated with that of RhoA (R = 0.562, p < 0.001) and RhoC (R = 0.529, p < 0.001), and their co-overexpressions correlated with metastatic HCC (p = 0.000012) and poor recurrence-free survival of HCC patients (p < 0.00001), which showed better prognostic significance than either Pin1, RhoA or RhoC overexpression alone. Co-overexpressions of Pin1 + RhoA/RhoC were also an independent factor for predicting development of metastasis after curative resection in our multivariate regression model (p < 0.001). CONCLUSION: Pin1, RhoA and RhoC co-overexpressions are prognostic factor for metastatic HCC and predict poor recurrence-free survival.

Suppression of Slit3 induces tumor proliferation and chemoresistance in hepatocellular carcinoma through activation of GSK3ß/ß-catenin pathway.

BACKGROUND: It is essential to understand the mechanisms responsible for hepatocellular carcinoma (HCC) progression and chemoresistance in order to identify prognostic biomarkers as well as potential therapeutic avenues. Recent findings have shown that SLIT3 appears to function as a novel tumor suppressor gene in various types of cancers, yet its clinical correlation and role in HCC has not been understood clearly. METHODS: We determined the transcript levels of Slit3 in tumor and adjacent normal tissues within two cohorts (N = 40 and 25) of HCC patients, and correlated the gene expression with the clinicopathological data. Subsequently, the functional effects and underlying molecular mechanisms of Slit3 overexpression and/or repression were studied using cell-line and mouse models. RESULTS: Our results demonstrated a repression in Slit3 expression in nearly 50% of the HCC patients, while the overall expression of Slit3 inversely correlated with the size of the tumor in both cohorts of patients. Stable down-regulation of Slit3 in HCC cell-lines induced cell proliferation in vitro and tumor growth in vivo, while stable Slit3 overexpression repressed these effects. Molecular investigations showed that the stable Slit3 repression-induced cell proliferation was associated with a higher expression of ß-catenin and a repressed GSK3ß activity. Moreover, Slit3-repression induced chemoresistance to sorafenib, oxaliplatin and 5-FU through impairment of ß-catenin degradation and induction of cyclin D3 and survivin levels. The effects induced by stable Slit3-repression were diminished by transient repression of ß-catenin by siRNA approach. CONCLUSION: This study suggests that Slit3 acts as a tumor suppressor in HCC by repressing the tumor growth and thus tumor progression. Low Slit3 level indicates a poor response of HCC cells to chemotherapy. Restoration or overexpression of Slit3 is a potential therapeutic approach to repress the tumor growth and enhance the efficacy of chemotherapeutic agents.

Emergence of CD26+ Cancer Stem Cells with Metastatic Properties in Colorectal Carcinogenesis.

Colorectal cancer results from genetic aberrations which accumulate over a long period of time, with malignant and metastatic properties acquired at a relatively late stage. A subpopulation of CD26+ colorectal cancer stem cells are known to be implicated in metastasis. We quantified CD26+ cancer cells in 11 primary tumor samples by flow cytometry, and showed that tumors having confirmed or suspected metastases harbored a relatively high CD26+ level in these samples. We hypothesized that this subpopulation of cancer stem cells arises in the late stage of carcinogenesis from the bulk of tumor daughter cells which are CD26-. The manipulation of PIK3CA and TP53, two genes commonly deregulated in the late stage, had an effect on the maintenance of the CD26+ cell population. When CD26- tumor daughter cells were sorted and cultured, the emergence of tumor spheres containing CD26+ cells occurred. These findings shed light to the origin of colorectal cancer stem cells with metastatic properties, which has an implication on conventional treatments by surgery or adjuvant chemotherapy for tumor debulking.

Nine-year experience of doxorubicin-eluting beads chemoembolization for hepatocellular carcinoma.

BACKGROUND: Chemoembolization with doxorubucin-eluting beads (DEB) has been used to treat hepatocellular carcinoma (HCC) since 2007. This study compared the efficacy and survival between transarterial chemoembolization (TACE) with DEB and conventional approach (cTACE) in HCC treatment. METHODS: This retrospective case-control study compared the overall survival and tumor response of HCC patients to cTACE (n=190) and DEB (n=143) by the reassessment of computed tomography and serum alpha-fetoprotein (AFP). Multivariate analysis was used to determine the factors affecting tumor response. RESULTS: The median post-treatment to pre-treatment AFP level was 0.8 for a DEB session (n=258) and 1.0 for a cTACE session (n=452), showing a significantly greater decrease in AFP after DEB (P<0.05). More patients in the DEB group achieved objective response (complete and partial) compared with those in the cTACE group (P<0.05). Objective tumor response after DEB vs cTACE was 34.8% vs 15.4% in 0-3 months (P=0.001), 37.1% vs 20.0% in 3-6 months (P<0.05), and 50.0% vs 30.0% in 6-12 months (P=0.093). DEB predicted a 3.604 times odds of achieving at least one objective tumor response in a patient when compared to cTACE (P<0.0001). The median survival from first transcatheter therapy of patients having undergone at least once DEB was 12.53 months, while those having received cTACE only was 10.53 months (P=0.086). A tendency of improved survival appeared to maintain until >80 months after the first TACE session in the DEB group. CONCLUSION: DEB is a safe alternative to cTACE in HCC patients with better therapeutic efficacy.

Preclinical analysis of the anti-tumor and anti-metastatic effects of Raf265 on colon cancer cells and CD26(+) cancer stem cells in colorectal carcinoma.

BACKGROUND: In colorectal carcinoma (CRC), activation of the Raf/MEK/ERK signaling pathway is commonly observed. In addition, the commonly used 5FU-based chemotherapy in patients with metastatic CRC was found to enrich a subpopulation of CD26(+) cancer stem cells (CSCs). As activation of the Raf/MEK/ERK signaling pathway was also found in the CD26(+) CSCs and therefore, we hypothesized that an ATP-competitive pan-Raf inhibitor, Raf265, is effective in eliminating the cancer cells and the CD26(+) CSCs in CRC patients. METHODS: HT29 and HCT116 cells were treated with various concentrations of Raf265 to study the anti-proliferative and apoptotic effects of Raf265. Anti-tumor effect was also demonstrated using a xenograft model. Cells were also treated with Raf265 in combination with 5FU to demonstrate the anti-migratory and invasive effects by targeting on the CD26(+) CSCs and the anti-metastatic effect of the combined treatment was shown in an orthotopic CRC model. RESULTS: Raf265 was found to be highly effective in inhibiting cell proliferation and tumor growth through the inhibition of the RAF/MEK/ERK signaling pathway. In addition, anti-migratory and invasive effect was found with Raf265 treatment in combination with 5FU by targeting on the CD26(+) cells. Finally, the anti-tumor and anti-metastatic effect of Raf265 in combination with 5FU was also demonstrated. CONCLUSIONS: This preclinical study demonstrates the anti-tumor and anti-metastatic activity of Raf265 in CRC, providing the basis for exploiting its potential use and combination therapy with 5FU in the clinical treatment of CRC.

Preliminary efficacy, safety, pharmacokinetics, pharmacodynamics and quality of life study of pegylated recombinant human arginase 1 in patients with advanced hepatocellular carcinoma.

This study was designed to evaluate the efficacy, safety profile, pharmacokinetics, pharmacodynamics and quality of life of pegylated recombinant human arginase 1 (Peg-rhAgr1) in patients with advanced hepatocellular carcinoma (HCC). Patients were given weekly doses of Peg-rhAgr1 (1600 U/kg). Tumour response was assessed every 8 weeks using RECIST 1.1 and modified RECIST criteria. A total of 20 patients were recruited, of whom 15 were deemed evaluable for treatment efficacy. Eighteen patients (90%) were hepatitis B carriers. Median age was 61.5 (range 30-75). Overall disease control rate was 13%, with 2 of the 15 patients achieving stable disease for >8 weeks. The median progression-free survival (PFS) was 1.7 (95% CI: 1.67-1.73) months, with median overall survival (OS) of all 20 enrolled patients being 5.2 (95% CI: 3.3-12.0) months. PFS was significantly prolonged in patients with adequate arginine depletion (ADD) >2 months versus those who had ≤2 months of ADD (6.4 versus 1.7 months; p = 0.01). The majority of adverse events (AEs) were grade 1/2 non-hematological toxicities. Transient liver dysfunctions (25%) were the most commonly reported serious AEs and likely due to disease progression. Pharmacokinetic and pharmacodynamic data showed that Peg-rhAgr1 induced rapid and sustained arginine depletion. The overall quality of life of the enrolled patients was well preserved. Peg-rhAgr1 is well tolerated with a good toxicity profile in patients with advanced HCC. A weekly dose of 1600 U/kg is sufficient to induce ADD. Significantly longer PFS times were recorded for patients who had ADD for >2 months.

Advanced pancreatic cancer: flourishing novel approaches in the era of biological therapy.

The progress in the development of systemic treatment for advanced pancreatic cancer (APC) has been slow. The mainstream treatment remains using chemotherapy including gemcitabine, FOLFIRINOX, and nab-paclitaxel. Erlotinib is the only approved biological therapy with marginal benefit. Studies of agents targeting epidermal growth factor receptor, angiogenesis, and RAS signaling have not been satisfying, and the usefulness of targeted therapy in APC is uncertain. Understanding in molecular processes and tumor biology has opened the door for new treatment strategies such as targeting insulin-like growth factor 1 receptor, transforming growth factor ß, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Notch pathway. New directions also include the upcoming immunotherapy and many novel agents that act on the microenvironment. The practice of personalized medicine using predictive biomarkers and pharmacogenomics signatures may also enhance the effectiveness of existing treatment. Future treatment approaches may involve comprehensive genomic assessment of tumor and integrated combinations of multiple agents to overcome treatment resistance.

PIN1 inhibits apoptosis in hepatocellular carcinoma through modulation of the antiapoptotic function of survivin.

PIN1, a peptidyl-prolyl-isomerase, binds a specific motif comprising a phosphorylated serine or threonine preceding a proline (p-Ser/Thr-Pro) residue in proteins. Through cis-trans isomerization, it induces conformational changes and modulates functions of many proteins that are involved in cell cycle progression, cell proliferation, and oncogenesis. PIN1 is overexpressed in hepatocellular carcinomas (HCC) and contributes to hepatocarcinogenesis. We investigated the role of PIN1 and the significance of its interaction with the inhibitor of apoptosis protein survivin in evading apoptosis in HCC cells. Using cell line and xenograft models, we determined that PIN1 overexpression inhibits apoptosis through suppression of caspase-3 and caspase-9 activity. In addition, down-regulation of survivin in PIN1-overexpressing cells attenuated the antiapoptotic effect induced by PIN1, suggesting that the inhibition of apoptosis is mediated through PIN1-survivin interaction. Coimmunoprecipitation assays showed that PIN1 interacted with survivin via the phosphorylated Thr34-Pro35 motif and enhanced binding among survivin phosphorylated at Thr34, hepatitis B X-interacting protein (HBXIP), and pro-caspase-9. Taken together, these results suggest that the inhibition of apoptosis by PIN1 in HCC cells is mediated through modulation of the antiapoptotic function of survivin by increasing its binding to pro-caspase-9 via HBXIP. Such functional interaction between PIN1 and survivin may therefore play an important role in hepatocarcinogenesis and chemoresistance.

Suppression of actopaxin impairs hepatocellular carcinoma metastasis through modulation of cell migration and invasion.

UNLABELLED: Early reports suggested that actopaxin, a member of the focal adhesion proteins, regulates cell migration. Here we investigated whether actopaxin is involved in hepatocellular carcinoma (HCC) progression and metastasis. We examined actopaxin expression in human HCC samples using immunohistochemistry and western blotting. The functional and molecular effect of actopaxin was studied in vitro by overexpression in a nonmetastatic HCC cell line, as well as repression in a metastatic cell line. The in vivo effect of actopaxin repression was studied in nonobese diabetic and severe combined immunodeficient mice. We found that actopaxin was frequently overexpressed in human HCC patients and its overexpression positively correlated with tumor size, stage, and metastasis. Actopaxin expression also correlated with the metastatic potential of HCC cell lines. Actopaxin overexpression induced the invasion and migration ability of nonmetastatic HCC cells, whereas down-regulation of actopaxin reverted the invasive phenotypes and metastatic potential of metastatic HCC cells through regulating the protein expression of certain focal adhesion proteins including ILK, PINCH, paxillin, and cdc42, as well as regulating the epithelial-mesenchymal transition pathway. Furthermore, there was a close association between actopaxin and CD29. HCC cells with stronger CD29 expression showed a higher actopaxin level, whereas actopaxin repression attenuated CD29 activity. Finally, actopaxin down-regulation enhanced the chemosensitivity of HCC cells towards oxaliplatin treatment by way of a collective result of suppression of survivin protein, ß-catenin, and mammalian target of rapamycin pathways and up-regulation of p53. CONCLUSION: This study provides concrete evidence of a significant role of actopaxin in HCC progression and metastasis, by way of regulation of cell invasiveness and motility, an epithelial-mesenchymal transition process, and chemosensitivity to cytotoxic drugs.

Biomarkers for predicting future metastasis of human gastrointestinal tumors.

The recent advances in surgery and radiation therapy have significantly improved the prognosis of patients with primary cancer, and the major challenge of cancer treatment now is metastatic disease development. The 5-year survival rate of cancer patients who have distant metastasis at diagnosis is extremely low, suggesting that prediction and early detection of metastasis would definitely improve their prognosis because suitable patient therapeutic management and treatment strategy can be provided. Cancer cells from a primary site give rise to a metastatic tumor via a number of steps which require the involvement and altered expression of many regulators. These regulators may serve as biomarkers for predicting metastasis. Over the past few years, numerous regulators have been found correlating with metastasis. In this review, we summarize the findings of a number of potential biomarkers that are involved in cadherin-catenin interaction, integrin signaling, PI3K/Akt/mTOR signaling and cancer stem cell identification in gastrointestinal cancers. We will also discuss how certain biomarkers are associated with the tumor microenvironment that favors cancer metastasis.

A Four-Gene Panel in Rectal Swab Samples as a Biomarker for Colorectal Cancer Screening.

BACKGROUND: The dysregulation of gene expression is one of the key molecular features of colorectal cancer (CRC) development. This study aimed to investigate whether such dysregulation is reflected in rectal swab specimens of CRC patients and to evaluate its potential as a non-invasive approach for screening. METHODS: We compared the expression level of 14 CRC-associated genes in tumor and adjacent non-tumor tissue of CRC patients and examined the correlation of their levels in tissue with paired rectal swab specimens. The level of these 14 genes in rectal swab specimens was compared among patients with CRC or polyp and control subjects, and the diagnostic potential of each dysregulated gene and the gene panel were evaluated. RESULTS: The expression of CXCR2, SAA, COX1, PPARδ, PPARγ, Groγ, IL8, p21, c-myc, CD44 and CSF1 was significantly higher in CRC, and there was a significant correlation in the levels of most of them between the CRC and rectal swab specimens. In the training study, we showed that CD44, IL8, CXCR2 and c-myc levels were significantly higher in the rectal swab specimens of the CRC patients. Such result was confirmed in the validation study. A panel of these four genes was developed, and ROC analysis showed that this four-gene panel could identify CRC patients with an AUC value of 0.83 and identify overall polyp and precancerous adenoma patients with AUC values of 0.6522 and 0.7322, respectively. Finally, the predictive study showed that the four-gene panel demonstrated sensitivities of 63.6%, 76.9% and 88.9% in identifying overall polyp, precancerous adenoma and CRC patients, respectively, whereas the specificity for normal subjects was 72.2%. CONCLUSION: The expression of CRC-associated genes in rectal swab specimens reflects the dysregulation status in colorectal tissue, and the four-gene panel is a potential non-invasive biomarker for early precancerous adenoma and CRC screening.

A phase 1 dose-escalating study of pegylated recombinant human arginase 1 (Peg-rhArg1) in patients with advanced hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) cells are auxotrophic for arginine, depletion of which leads to tumour regression. The current study evaluated safety, pharmacokinetics (PK)/ pharmacodynamics (PD) parameters, and potential anti-tumor activity of pegylated recombinant human arginase 1 (peg-rhArg1) in advanced HCC patients. METHODS: Eligibility criteria included advanced HCC with measurable lesions, Child-Pugh A or B, and adequate organ function. Initial single IV bolus was followed by weekly doses of peg-rhArgI escalated from 500 U/kg to 2500 U/kg in a 3 + 3 design. RESULTS: Fifteen patients were enrolled at weekly doses of 500 U/kg (n = 3), 1000 U/kg (n = 3), 1600 U/kg (n = 3) and 2500 U/kg (n = 6). The median age was 57 years (33-74); 87% were hepatitis B carriers and 47% had prior systemic treatment. The most commonly reported drug-related non-haematological adverse events (AEs) were diarrhea (13.3%), abdominal discomfort (6.7%) and nausea (6.7%). No drug-related haematological AEs were seen. Only 1 of the six patients that received 2500U/kg peg-rhArg1 experienced DLT (grade 4 bilirubin elevation) and thus the maximum tolerated dose was 2500 U/kg. PK and PD analysis indicated that peg-rhArg1 was efficacious in inducing arginine depletion in a dose-dependent manner. Adequate arginine depletion dose was achieved in the 1,600-2,500 U/kg range and therefore the optimal biological dose was at 1600 U/kg, which was chosen as the recommended dose. The best response was stable disease for >8 weeks in 26.7% of the enrolled patients. CONCLUSION: Peg-rhArg1 has manageable safety profile and preliminary evidence of activity in advanced HCC patients.

Identification of CD44+ cancer stem cells in human gastric cancer.

The cancer stem cell hypothesis suggests that tumors are initiated and maintained by cancer stem cells capable of self-renewal and differentiation into mature tumor cells. Recent studies have demonstrated the existence of cancer initiating cells in different solid tumors. In this study, we identified a subpopulation of CD44+ cells within the tumor of gastric cancer patients, which, upon treatment by chemotherapeutic agent 5-fluorouracil (5-FU), were markedly enriched. In vitro culture of isolated CD44+ subpopulation from gastric tumors by magnetic beads sorting led to formation of gastric spheroid colonies. These colonies retained CD44+ surface marker expression during culture, and were undifferentiated in nature. Subcutaneous injections of CD44+ gastric cancer cells conferred tumorigenicity in SCID mice. Moreover, implantation of CD44+ cells from these established tumors remained tumorigenic in successive passages. Using CD44+ cells isolated from the gastric cell lines AGS and SGC7901, similar results were obtained. Upon enrichment by 5-FU, CD44+ cells harbored increased ALDH expression as compared with CD44- cells. Our results demonstrated for the first time the existence of CD44+ cells within the tumors of gastric cancer patients that are endowed with stem cells properties, and also provide a plausible explanation for chemo-resistance frequently observed in gastric cancer patients. Such findings provide a basis for further studies on targeting this tumorigenic subpopulation for better treatment of gastric cancer patients.

The use of single-agent sorafenib in the treatment of advanced hepatocellular carcinoma patients with underlying Child-Pugh B liver cirrhosis: a retrospective analysis of efficacy, safety, and survival benefits.

BACKGROUND: This study explored the efficacy, tolerability, and survival benefits of using sorafenib in patients with Child-Pugh class B (CPB) cirrhosis. METHODS: Patients with advanced hepatocellular carcinoma who were treated with sorafenib at Queen Mary Hospital, Hong Kong, China, were analyzed retrospectively. Treatment outcomes were analyzed according to their respective Child-Pugh status. Patients with CPB disease were further divided into CPB7 (those with a score of 7) and CPB8-9 (a score of 8 or 9) subgroups. RESULTS: The baseline demographic parameters were comparable between 108 patients with Child-Pugh class A (CPA) disease and 64 CPB patients. Both clinical benefit rate (21.3% vs 32.4% vs 14.8%; P = .23) and progression-free survival (median: 3.2 months vs 3.2 months vs 2.3 months; P = .26) were similar among CPA, CPB7, and CPB8-9 groups, respectively. The overall survival was different among these groups (P = .002) and showed a trend toward worse outcome in CPB patients: the median was 6.1, 5.4, and 2.7 months among CPA, CPB7, and CPB8-9 patients, respectively. The commonest grade 3/4 adverse events were hand-foot syndrome (13.5%), diarrhea (9.9%), and rash (7.0%). Grade 3/4 leukopenia, thrombocytopenia, and anemia occurred in 2.9%, 5.3%, and 8.8% of the patients, respectively. Overall, the 3 groups of patients experienced similar incidence of most of these adverse events. Nonetheless, CPB patients experienced more anemia (P = .01), gastrointestinal bleeding (P = .02), and hepatic encephalopathy (P = .02). CONCLUSIONS: CPA and CPB patients tolerated sorafenib similarly and derived similar clinical and progression-free survival benefit. Among CPB patients, most benefits were observed in patients with a score of 7. Nevertheless, CPB patients were more susceptible to developing cirrhotic complications, and thus more vigilant surveillance is needed.

XIAP-associated factor 1 (XAF1), a novel target of p53, enhances p53-mediated apoptosis via post-translational modification.

The role of X chromosome-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (XAF1) in mediating apoptosis has been reported but the underlying mechanism remains unclear. The present study was designed to examine the putative interaction between XAF1 and p53 and the functional importance of this interaction in regulation of apoptosis in human gastric and colon cancer cells. We first identified XAF1 as a novel target gene of p53 by the chromatin immunoprecipitation (CHIP) assay and demonstrated that wild-type p53, but not mutant p53, down-regulated XAF1 at both mRNA and protein levels, which acted mostly under the condition of high expression of XAF1 and was associated with the physical interaction between p53 and the XAF1 promoter. We also found that the over-expression of XAF1 led to activation of wild-type p53 via post-translational modification in cells with or without DNA damage, which resulting in p53 nuclear accumulation and its increased transcriptional activity and enhancing p53-dependent apoptosis. These findings suggest that a potential novel feedback loop exists between XAF1 and wild-type p53.

High Expression of a Cancer Stemness-Related Gene, Chromobox 8 (CBX8), in Normal Tissue Adjacent to the Tumor (NAT) Is Associated with Poor Prognosis of Colorectal Cancer Patients.

BACKGROUND: Several studies have demonstrated that the molecular profile of normal tissue adjacent to the tumor (NAT) is prognostic for recurrence in patients with different cancers. This study investigated the clinical significance of CBX8 gene expression, a cancer stemness-related gene, in tumor and NAT tissue of colorectal cancer (CRC) patients. METHODS: The gene level of CBX8 in paired CRC and NAT specimens from 95 patients was determined by quantitative PCR. CBX8 protein level in CRC and NAT specimens from 66 patients was determined by immunohistochemistry. CBX8 gene and protein levels were correlated with the patients' clinicopathological parameters and circulatory immune cell profiles. The association between CBX8 and pluripotency-associated genes was analyzed using the TCGA database. RESULTS: NAT CBX8 gene level positively correlated with TNM stage, tumor invasion, lymph node metastasis and distant metastasis, indicating its association with tumor progression and metastasis. There was no correlation between NAT CBX8 protein level and clinicopathological parameters. Moreover, a high level of CBX8 gene and protein in NAT both correlated with poor DFS and OS. There was an inverse correlation between CBX8 gene level and post-operative platelet counts and platelet to lymphocyte level, suggesting its association with systematic inflammation. Finally, TCGA analysis showed that CBX8 level was correlated with a couple of pluripotency-associated genes, supporting its association with cancer stemness. CONCLUSIONS: High NAT CBX8 is a poor prognostic factor for tumor progression and survival in CRC patients.

The significance of early alpha-fetoprotein level changes in predicting clinical and survival benefits in advanced hepatocellular carcinoma patients receiving sorafenib.

BACKGROUND: he role of serum alpha-fetoprotein (AFP) changes in predicting the treatment outcomes of advanced hepatocellular carcinoma (HCC) patients to sorafenib remains unknown. METHODS: Serum AFP was collected prospectively at baseline and subsequent follow-up visits in parallel with clinical and survival outcomes. AFP response was defined as a relative drop of AFP >20% of the baseline level after 6 weeks of sorafenib. The relationship between AFP response and the treatment outcomes was first explored in patients who received sorafenib in a phase II study. Subsequently, an independent validation set of patients were obtained to validate the association of AFP response to clinical outcomes. RESULTS: Included in the exploration and validation sets for analysis were 41 and 53 patients, respectively, with baseline AFP level >20 µg/L. In the exploration cohort, AFP response was significantly associated with clinical benefit (CB) rate (relative chance 3.4, 95% confidence interval [CI], 1.1-11.1), and multivariate analysis indicated that AFP response was associated with significantly better progression-free survival (PFS) (hazard ratio [HR], 0.31; 95% CI, 0.13-0.76) and marginally better overall survival (OS) (HR, 0.30; 95% CI, 0.09-1.02). When applying AFP changes in the validation set, significant associations were again found between AFP response with CB rate (relative chance, 5.5; 95% CI, 2.3-13.6) and PFS (HR, 0.12; 95% CI, 0.04-0.30) but not OS (HR, 0.61; 95% CI, 0.27-1.26). CONCLUSION: Drop in AFP level at 6 weeks is an exploratory early surrogate for both CB and PFS in advanced HCC patients receiving sorafenib.

The outcomes and safety of single-agent sorafenib in the treatment of elderly patients with advanced hepatocellular carcinoma (HCC).

BACKGROUND: With the aging population, hepatocellular carcinoma (HCC) in the elderly represents a significant health burden. We aimed to evaluate and compare the efficacy and tolerability of single-agent sorafenib in treating elderly patients with advanced HCC versus the younger population. METHODS: We retrospectively analyzed a consecutive cohort of advanced HCC patients with Child-Pugh A or B liver function and an Eastern Cooperative Oncology Group performance status score of 0-2 treated with sorafenib. The patients were categorized into older (age ≥70 years) and younger (age <70 years) groups. Treatment outcomes and related adverse events (AEs) were compared. RESULTS: In total, 172 patients, 35 in the older (median age, 73 years) and 137 in the younger (median age, 55 years) group, were analyzed. The median progression-free survival time was similar in the older and younger groups (2.99 months versus 3.09 months; p = .275), as was the overall survival time (5.32 months versus 5.16 months; p = .310). Grade 3 or 4 AEs were observed in 68.6% of older and 62.7% of younger patients (p = .560), with neutropenia (11.4% versus 0.7%; p = .007), malaise (11.4% versus 2.2%; p = .033), and mucositis (5.7% versus 0.0%; p = .041) being more frequently reported in the elderly cohort. CONCLUSIONS: The survival benefits and overall treatment-related AEs of sorafenib are comparable in elderly and younger advanced HCC patients. Nevertheless, more vigilant monitoring in the elderly is warranted because they are more susceptible to develop neutropenia, malaise, and mucositis.