Therapeutic Strategies in Diseases of the Digestive Tract - 2015 and Beyond Targeted Therapies in Colon Cancer Today and Tomorrow

Depletion of CPNE7 sensitizes colorectal cancer to 5-fluorouracil by downregulating ATG9B expression

We aimed to explore the biological function of CPNE7 and determine the impact of CPNE7 on chemotherapy resistance in colorectal cancer (CRC) patients. According to the Gene Expression Profiling Interactive Analysis database and previously published data, CPNE7 was identified as a potential oncogene in CRC. RT-qPCR and Western blotting were performed to verify the expression of CPNE7. Chi-square test was used to evaluate the associations between CPNE7 and clinical features. Cell proliferation, colony formation, cell migration and invasion, cell cycle and apoptosis were assessed to determine the effects of CPNE7. Transcriptome sequencing was used to identify potential downstream regulatory genes, and gene set enrichment analysis was performed to investigate downstream pathways. The effect of CPNE7 on 5-fluorouracil chemosensitivity was verified by half maximal inhibitory concentration (IC50). Subcutaneous tumorigenesis assay was used to examine the role of CPNE7 in sensitivity of CRC to chemotherapy in vivo. Transmission electron microscopy was used to detect autophagosomes. CPNE7 was highly expressed in CRC tissues, and its expression was correlated with T stage and tumour site. Knockdown of CPNE7 inhibited the proliferation and colony formation of CRC cells and promoted apoptosis. Knockdown of CPNE7 suppressed the expression of ATG9B and enhanced the sensitivity of CRC cells to 5-fluorouracil in vitro and in vivo. Knockdown of CPNE7 reversed the induction of the autophagy pathway by rapamycin and reduced the number of autophagosomes. Depletion of CPNE7 attenuated the malignant proliferation of CRC cells and enhanced the chemosensitivity of CRC cells to 5-fluorouracil.

Construction and validation of a progression prediction model for locally advanced rectal cancer patients received neoadjuvant chemoradiotherapy followed by total mesorectal excision based on machine learning

Background

We attempted to develop a progression prediction model for local advanced rectal cancer(LARC) patients who received preoperative neoadjuvant chemoradiotherapy(NCRT) and operative treatment to identify high-risk patients in advance.

Methods

Data from 272 LARC patients who received NCRT and total mesorectal excision(TME) from 2011 to 2018 at the Fourth Hospital of Hebei Medical University were collected. Data from 161 patients with rectal cancer (each sample with one target variable (progression) and 145 characteristic variables) were included. One Hot Encoding was applied to numerically represent some characteristics. The K-Nearest Neighbor (KNN) filling method was used to determine the missing values, and SmoteTomek comprehensive sampling was used to solve the data imbalance. Eventually, data from 135 patients with 45 characteristic clinical variables were obtained. Random forest, decision tree, support vector machine (SVM), and XGBoost were used to predict whether patients with rectal cancer will exhibit progression. LASSO regression was used to further filter the variables and narrow down the list of variables using a Venn diagram. Eventually, the prediction model was constructed by multivariate logistic regression, and the performance of the model was confirmed in the validation set.

Results

Eventually, data from 135 patients including 45 clinical characteristic variables were included in the study. Data were randomly divided in an 8:2 ratio into a data set and a validation set, respectively. Area Under Curve (AUC) values of 0.72 for the decision tree, 0.97 for the random forest, 0.89 for SVM, and 0.94 for XGBoost were obtained from the data set. Similar results were obtained from the validation set. Twenty-three variables were obtained from LASSO regression, and eight variables were obtained by considering the intersection of the variables obtained using the previous four machine learning methods. Furthermore, a multivariate logistic regression model was constructed using the data set; the ROC indicated its good performance. The ROC curve also verified the good predictive performance in the validation set.

Conclusions

We constructed a logistic regression model with good predictive performance, which allowed us to accurately predict whether patients who received NCRT and TME will exhibit disease progression.

Immunotherapy for colorectal cancer: Rational strategies and novel therapeutic progress

There are increasing incidences and mortality rates for colorectal cancer in the world. It is common for chemotherapy and radiation given to patients with colorectal cancer to cause toxicities that limit their effectiveness and cause cancer cells to become resistant to these treatments. Additional targeted treatments are needed to improve patient's quality of life and outcomes. Immunotherapy has rapidly emerged as an incredibly exciting and promising avenue for cancer treatment in recent years. This innovative approach provides novel options for tackling solid tumors, effectively establishing itself as a new cornerstone in cancer treatment. Specifically, in the realm of colorectal cancer (CRC), there is great promise in developing new drugs that target immune checkpoints, offering a hopeful and potentially transformative solution. While immunotherapy of CRC has made significant advances, there are still obstacles and limitations. CRC patients have a poor response to treatment because of the immune-suppressing function of their tumor microenvironment (TME). In addition to blocking inhibitory immune checkpoints, checkpoint-blocking antibodies may also boost immune responses against tumors. The review summarizes recent advances in immune checkpoint inhibitors (ICIs) for CRC, including CTLA-4, PD-1, PD-L1, LAG-3, and TIM-3.

Immuno-Contexture and Immune Checkpoint Molecule Expression in Mismatch Repair Proficient Colorectal Carcinoma

Colorectal carcinoma (CRC) represents a lethal disease with heterogeneous outcomes. Only patients with mismatch repair (MMR) deficient CRC showing microsatellite instability and hyper-mutated tumors can obtain clinical benefits from current immune checkpoint blockades; on the other hand, immune- or target-based therapeutic strategies are very limited for subjects with mismatch repair proficient CRC (CRC^pMMR). Here, we report a comprehensive typing of immune infiltrating cells in CRC^pMMR. We also tested the expression and interferon-γ-modulation of PD-L1/CD274. Relevant findings were subsequently validated by immunohistochemistry on fixed materials. CRC^pMMR contain a significantly increased fraction of CD163⁺ macrophages (TAMs) expressing TREM2 and CD66⁺ neutrophils (TANs) together with decrease in CD4^-CD8^-CD3⁺ double negative T lymphocytes (DNTs); no differences were revealed by the analysis of conventional and plasmacytoid dendritic cell populations. A fraction of tumor-infiltrating T-cells displays an exhausted phenotype, co-expressing PD-1 and TIM-3. Remarkably, expression of PD-L1 on fresh tumor cells and TAMs was undetectable even after in vitro stimulation with interferon-γ. These findings confirm the immune suppressive microenvironment of CRC^pMMR characterized by dense infiltration of TAMs, occurrence of TANs, lack of DNTs, T-cell exhaustion, and interferon-γ unresponsiveness by host and tumor cells. Appropriate bypass strategies should consider these combinations of immune escape mechanisms in CRC^pMMR.

Recruiting Immunity for the Fight against Colorectal Cancer: Current Status and Challenges

Cancer immunotherapies have changed the landscape of cancer management and improved the standard treatment protocols used in multiple tumors. This has led to significant improvements in progression-free survival and overall survival rates. In this review article, we provide an insight into the major immunotherapeutic methods that are currently under investigation for colorectal cancer (CRC) and their clinical implementations. We emphasize therapies that are based on monoclonal antibodies (mAbs) and adoptive cell therapy, their mechanisms of action, their advantages, and their potential in combination therapy. We also highlight the clinical trials that have demonstrated both the therapeutic efficacy and the toxicities associated with each method. In addition, we summarize emerging targets that are now being evaluated as potential interventions for CRC. Finally, we discuss current challenges and future direction for the cancer immunotherapy field.

Colorectal liver metastasis: molecular mechanism and interventional therapy

Colorectal cancer (CRC) is one of the most frequently occurring malignancy tumors with a high morbidity additionally, CRC patients may develop liver metastasis, which is the major cause of death. Despite significant advances in diagnostic and therapeutic techniques, the survival rate of colorectal liver metastasis (CRLM) patients remains very low. CRLM, as a complex cascade reaction process involving multiple factors and procedures, has complex and diverse molecular mechanisms. In this review, we summarize the mechanisms/pathophysiology, diagnosis, treatment of CRLM. We also focus on an overview of the recent advances in understanding the molecular basis of CRLM with a special emphasis on tumor microenvironment and promise of newer targeted therapies for CRLM, further improving the prognosis of CRLM patients.

Hydroxypropyl-β-Cyclodextrin Complexes of Styryllactones Enhance the Anti-Tumor Effect in SW1116 Cell Line

Styryllactones, a class of compounds obtained from the genus Goniothalamus (Annonaceae), have demonstrated in vitro antitumor activity. However, the aqueous solubility of these compounds is poor. In this study, we identified the absolute configurations of the previously isolated compounds, which were first isolated in our laboratory, by single-crystal X-ray diffraction analysis using Cu Kα radiation. Subsequently, the antitumor activities of the compounds were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide staining in four tumor cell lines. The induced apoptosis activity of leiocarpin E-7'-Monoacetate was studied by an annexin V fluorescein isothiocyanate/propidium iodide double-staining experiment, and the caspase activity was tested in the SW1116 cell line. The results demonstrated that the antitumor activities of cheliensisin A and goniodiol-7-monoacetate were limited by their poor water solubility. To address this issue, hydroxypropyl-β-cyclodextrin (HP-β-CD) complexes of the compounds were synthesized by the saturated aqueous method. The complexes were then analyzed using a differential scanning calorimeter. The IC₅₀ of cheliensisin A was reduced by 45% and 58% against SW1116 and SMMC-7721 cell lines, respectively. Similarly, the IC₅₀ of goniodiol-7-monoacetate was reduced by 55% and 34% against the two tumor cell lines, respectively. To further evaluate whether the styryllactones and complexes possessed selectivity against cancer cell lines and normal cell lines, toxicity against human normal cell line (HEK293T) was evaluated. The results demonstrated that the HP-β-CD complexes displayed more cytotoxicity than the respective pristine compounds against the HEK293T cell line. However, there existed a therapeutic window when the complexes were applied against cancer cell lines. In summary, the synthesis of several styryllactone compounds complexed with HP-β-CD was reported for the first time. These complexes could significantly enhance the cytotoxic effects of styryllactone compounds.

Profiling of serum metabolites in advanced colon cancer using liquid chromatography-mass spectrometry

Lymph node metastasis remains a key factor that affects the prognosis of patients with colon cancer. The aim of the present study was to identify and evaluate serum metabolites as biomarkers for the detection of tumor lymph node metastasis and the prediction of patient survival. The present study analyzed the metabolites in the serum of patients with advanced colon cancer both with and without lymph node metastasis. Blood samples from 104 patients with stage T3 colon cancer were collected and analyzed using liquid chromatography-mass spectrometry. The metabolites were structurally confirmed with data from the Human Metabolome Database. The association between the serum metabolites and the clinicopathological characteristics and survival time of patients from the present study was analyzed. Overall, 227 different metabolites were identified in the serum of patients with stage T3 colon cancer with or without lymph node metastasis. Furthermore, 17 of these metabolites may potentially distinguish those patients with lymph node metastasis from those patients without. In addition, five factors, including abscisic acid, calcitroic acid and glucosylsphingosine presence in the serum, age and sex, were identified as independent predictors for lymph node metastasis (P<0.05). Furthermore, three factors, including abscisic acid, calcitroic acid and glucosylsphingosine presence in the serum were independent predictors for patient survival (P<0.05). In conclusion, the serum levels of abscisic acid, calcitroic-acid and glucosylsphingosine may be considered as potential biomarkers to predict the occurrence of lymph node metastasis and the survival time of patients with colon cancer.

Collagen Kinase Receptors as Potential Therapeutic Targets in Metastatic Colon Cancer

Colorectal cancer (CRC) is one of the leading causes of tumor-related death worldwide. While surgery can cure patients with early stage CRC, the 5-year survival rate is only 10% for patients with metastatic disease. Therefore, new anti-metastatic therapies are needed for this cancer. Metastatic spread defines the dissemination of cancer cells with tumor-initiating capacities from the primary tumor and their colonization of distinct organs, mainly the liver, for secondary tumor formation. Although the underlying mechanisms are not fully understood, components of the tumor microenvironment have gained strong interest. Among the known metastatic-promoting factors, collagens are extracellular matrix components that are deposited within the tumor, the tumor microenvironment, and at metastatic site(s), and are recognized to play essential roles during metastasis development. Here, we review recent findings on the metastatic role of the collagen receptors Discoidin Domain Receptors 1 and 2 (DDR1 and DDR2) in CRC and discuss the therapeutic value of targeting these receptor tyrosine kinases in this cancer.

Roles of exosomes in metastatic colorectal cancer

Metastases remain a major cause of cancer morbidity and mortality. This is a multistep process that involves aberrant cell communication, leading to tumor cell dissemination from the primary tumor and colonization of distinct organs for secondary tumor formation. The mechanisms promoting this pathological process are not fully understood, although they may be of obvious therapeutic interest. Exosomes are small cell-secreted vesicles that contain a large variety of proteins, lipids, and nucleic acids with important signaling activities, and that represent an evolutionarily conserved mechanism for cell-to-cell communication. Not surprisingly, exosome activities have gained strong interest in cancer biology and might play essential roles in metastasis development. Here, we will describe recent findings on the role of exosomes in cancer metastasis formation, particularly in colorectal cancer (CRC). We will also discuss the potential therapeutic value of these vesicles in metastatic cancer.

Control of Tyrosine Kinase Signalling by Small Adaptors in Colorectal Cancer

Tyrosine kinases (TKs) phosphorylate proteins on tyrosine residues as an intracellular signalling mechanism to coordinate intestinal epithelial cell communication and fate decision. Deregulation of their activity is ultimately connected with carcinogenesis. In colorectal cancer (CRC), it is still unclear how aberrant TK activities contribute to tumour formation because TK-encoding genes are not frequently mutated in this cancer. In vertebrates, several TKs are under the control of small adaptor proteins with potential important physiopathological roles. For instance, they can exert tumour suppressor functions in human cancer by targeting several components of the oncogenic TK signalling cascades. Here, we review how the Src-like adaptor protein (SLAP) and the suppressor of cytokine signalling (SOCS) adaptor proteins regulate the SRC and the Janus kinase (JAK) oncogenic pathways, respectively, and how their loss of function in the intestinal epithelium may influence tumour formation. We also discuss the potential therapeutic value of these adaptors in CRC.

Contribution of IL-33 to the Pathogenesis of Colorectal Cancer

The development of colorectal cancer (CRC) is not only determined by transformed cells per se, but also by factors existing in their immune microenvironment. Accumulating scientific evidence has revealed that interleukin (IL)-33, an IL-1 family member, plays an essential role in the regulation of immune response and is relevant in CRC pathogenesis. Data from both human and experimental studies demonstrated that IL-33 inhibits host anti-tumor immunity, remodels tumor stroma and enhances angiogenesis, thereby promoting the development of CRC. These pro-tumor effects of IL-33 are mainly mediated by IL-33 receptor ST2 (also known as IL-1RL1). Based on those findings, it is currently hypothesized that the IL-33/ST2 pathway is a potential biomarker and therapeutic target for colorectal tumorigenesis. Herein, we summarize the recent discoveries in understanding the critical role of the IL-33/ST2 pathway in contributing to the pathogenesis of colorectal tumorigenesis and discuss its potential implications for the future development of effective anti-tumor strategies.

The Effects of Different mTOR Inhibitors in EGFR Inhibitor Resistant Colon Carcinoma Cells

Several monoclonal antibodies and inhibitors targeting signalling pathways are being used in personalised medicine. Anti-EGFR antibodies seem to be effective, however, therapy resistance often occurs in colon carcinoma cases. mTOR inhibitors (mTORIs) could have a potential role in the breakthrough of therapy resistance. The mTOR activity related protein expression patterns and the in vitro effects of EGFR inhibitors (EGFRIs), mTORIs and their combinations were studied in different colon carcinoma cell lines (with different genetic backgrounds). Alamar Blue test and flow cytometry were used to analyse the in vitro proliferation and apoptotic effects of cetuximab, gefitinib, cisplatin, rapamycin, PP242 and NVP-BEZ235. The expressions of mTOR activity related proteins (p-70S6K, p-S6, Rictor, p-mTOR, Raptor) were studied by Western blot, immunocytochemistry and Duolink staining. The EGFRI resistance of the studied colon carcinoma cell lines related to their known mutations were confirmed, neither gefitinib nor cetuximab inhibited the proliferation or induced apoptosis in vitro. Individual differences in Rictor and Raptor expressions were detected by Western blot and immunocytochemistry beside elevated mTOR activity of these different colon carcinoma cell lines. These expression patterns correlated to the mTORIs sensitivity differences, moreover, mTORIs could enhance the effects of EGFRIs and other in vitro treatments. Our results suggest that mTORI combinations could be helpful in both EGFRI and platinum-based therapy of colon carcinomas. Moreover, we suggest determining both mTOR complex activity and mutations in Akt/mTOR signalling pathways for selecting the appropriate mTORIs and patients in potential future combination treatments.

shRNA-induced silencing of Ras-related C3 botulinum toxin substrate 1 inhibits the proliferation of colon cancer cells through upregulation of BAD and downregulation of cyclin D1

Ras-related C3 botulinum toxin substrate 1 (RAC1) is a member of the Rho family of small GTPases. Recent studies have reported that RAC1 serves an important role in colon cancer cell proliferation. The present study aimed to investigate the effects of RAC1 knockdown on cell proliferation, cell cycle progression and apoptosis of colon cancer cells. Lentivirus-mediated short hairpin RNA (shRNA) was used to knockdown RAC1 expression in colon cancer cell lines, and cell proliferation, apoptosis, cell cycle progression were evaluated by MTT assays and flow cytometry. The differences in mRNAs expression were identified between RAC1-knockdown cells and control cells using a mRNA microarray, following which quantitative PCR (qPCR) and western blot were employed to confirm the results of the mRNA microarray. The proliferative ability of colon cancer cells was significantly decreased following RAC1 knockdown, and RAC1 knockdown increased the apoptotic rate and enhanced cell cycle arrest at G₁ phase in colon cancer cells. In addition, >1,200 known genes were demonstrated to be involved in RAC1-associated tumorigenic functions in SW620 colon cancer cells, as determined by gene chip analysis; these genes were associated with cell proliferation, cell cycle, apoptosis and metastasis. Furthermore, western blot analysis indicated that cyclin D1 was downregulated, whereas B-cell lymphoma 2-associated agonist of cell death (BAD) was upregulated following RAC1 knockdown in colon cancer cells. In conclusion, RAC1 silencing may suppress the proliferation of colon cancer cells by inducing apoptosis and cell cycle arrest. In addition, a large number of genes were revealed to be involved in the process, including BAD, which was upregulated and cyclin D1, which was downregulated. Further studies on these differentially expressed genes may provide a better understanding of the potential roles of RAC1 in colon carcinogenesis.

Targeting the Wnt Pathway and Cancer Stem Cells with Anti-progastrin Humanized Antibodies as a Potential Treatment for K-RAS-Mutated Colorectal Cancer

Purpose: Patients with metastatic colorectal cancer suffer from disease relapse mainly due to cancer stem cells (CSC). Interestingly, they have an increased level of blood progastrin, a tumor-promoting peptide essential for the self-renewal of colon CSCs, which is also a direct β-catenin/TCF4 target gene. In this study, we aimed to develop a novel targeted therapy to neutralize secreted progastrin to inhibit Wnt signaling, CSCs, and reduce relapses.Experimental Design: Antibodies (monoclonal and humanized) directed against progastrin were produced and selected for target specificity and affinity. After validation of their effectiveness on survival of colorectal cancer cell lines harboring B-RAF or K-RAS mutations, their efficacy was assessed in vitro and in vivo, alone or concomitantly with chemotherapy, on CSC self-renewal capacity, tumor recurrence, and Wnt signaling.Results: We show that anti-progastrin antibodies decrease self-renewal of CSCs both in vitro and in vivo, either alone or in combination with chemotherapy. Furthermore, migration and invasion of colorectal cancer cells are diminished; chemosensitivity is prolonged in SW620 and HT29 cells and posttreatment relapse is significantly delayed in T84 cells, xenografted nude mice. Finally, we show that the Wnt signaling activity in vitro is decreased, and, in transgenic mice developing Wnt-driven intestinal neoplasia, the tumor burden is alleviated, with an amplification of cell differentiation in the remaining tumors.Conclusions: Altogether, these data show that humanized anti-progastrin antibodies might represent a potential new treatment for K-RAS-mutated colorectal patients, for which there is a crucial unmet medical need. Clin Cancer Res; 23(17); 5267-80. ©2017 AACR.

A retrospective study of docetaxel and bevacizumab as a second- or later-line chemotherapy for non-small cell lung cancer

Comparative results of second- or later-line bevacizumab plus docetaxel and docetaxel alone for patients with NSCLC have never been reported. In order to evaluate the combined effect of bevacizumab and docetaxel as second- or later-line chemotherapy for NSCLC, a retrospective study was performed. Between November 2009 and April 2016, the medical records of all the patients <75 years old who were treated with docetaxel (60 mg/m², day1, q3 or 4 weeks) plus bevacizumab (15 mg/kg, day 1, q3 or 4 weeks) as a second- or later-line chemotherapy were reviewed. Complete data sets were obtained from 15 patients treated with docetaxel plus bevacizumab, and 55 patients treated with docetaxel alone. The overall response rate to docetaxel plus bevacizumab therapy was 26.7, and 53.3% of these patients had stable disease (SD), amounting to a disease control rate of 80.0%. On the other hand, the overall response rate to docetaxel alone therapy was 9.1, and 38.2% of these patients had SD, amounting to a disease control rate of 47.3%. All the patients treated with docetaxel plus bevacizumab therapy had grade 3 or 4 'neutropenia' or 'febrile neutropenia', which developed in 100 and 26.7% of patients, respectively. The rates of these adverse events in patients treated with docetaxel alone were 63.6, and 10.9%, respectively. The mean progression free survival (PFS) in patients treated with docetaxel plus bevacizumab and that of patients with docetaxel alone was 5.9 and 2.1 months, respectively. There was a non-significant tendency towards a difference in survival between the two treatment groups (P=0.081, log-rank test). The possibility of improvement of response and prolongation of PFS in patients treated with second- or later line docetaxel and bevacizumab chemotherapy may be suggested in this study. However, the higher risk of febrile neutropenia must be noted for this combination of drugs.

YAP-IL-6ST autoregulatory loop activated on APC loss controls colonic tumorigenesis

Loss of tumor suppressor adenomatous polyposis coli (APC) activates β-catenin to initiate colorectal tumorigenesis. However, β-catenin (CTNNB1) activating mutations rarely occur in human colorectal cancer (CRC). We found that APC loss also results in up-regulation of IL-6 signal transducer (IL-6ST/gp130), thereby activating Src family kinases (SFKs), YAP, and STAT3, which are simultaneously up-regulated in the majority of human CRC. Although, initial YAP activation, which stimulates IL6ST gene transcription, may be caused by reduced serine phosphorylation, sustained YAP activation depends on tyrosine phosphorylation by SFKs, whose inhibition, along with STAT3-activating JAK kinases, causes regression of established colorectal tumors. These results explain why APC loss is a more potent initiating event than the mere activation of CTNNB1.

Immunotherapy for the treatment of colorectal tumors: focus on approved and in-clinical-trial monoclonal antibodies

Colorectal cancer is considered a disease of the elderly population. Since the number of geriatric patients continues to rise, monoclonal antibody therapy is the most promising therapy in the recent research. Presently, the monoclonal antibodies most frequently used in the treatment of colorectal tumors are bevacizumab, cetuximab, panitumumab, and ramucirumab. Bevacizumab is a monoclonal antibody that acts on VEGF. Cetuximab and panitumumab act on EGFR. Ramucirumab binds directly to the ligand-binding pocket of VEGFR-2 to block the binding of VEGF-A, VEGF-C, and VEGF-D. These monoclonal antibodies, alone or in association with radiotherapy or chemotherapy, are presenting good results and are increasing patient survival, despite the side effects. Due to the limited number of molecules available, several studies are trying to develop new monoclonal antibodies for the treatment of colorectal tumors. Among those being studied, some recent molecules are in phase I and/or II trials and are yielding advantageous results, such as anti-DR5, anti-Fn14, anti-IGF-1R, anti-EGFR, anti-NRP1, and anti-A33 antibodies. This has been successful in reducing side effects and in treating nonresponsive patients.