Global chemotherapy development for gastric cancer

The AKT inhibitor AZD5363 elicits synthetic lethality in ARID1A-deficient gastric cancer cells via induction of pyroptosis

BACKGROUND

Gastric cancer (GC) is a deadly disease with poor overall survival and limited therapeutic options. Genetic alterations such as mutations and/or deletions in chromatin remodeling gene AT-rich interactive domain 1 A (ARID1A) occur frequently in GC. Although ARID1A mutations/deletions are not a druggable target for conventional treatments, novel therapeutic strategies based on a synthetic lethal approach may be effective for the treatment of ARID1A-deficient cancers.

METHODS

A kinase inhibitor library containing 551 compounds was screened in ARID1A isogenic GC cells for the ability to induce synthetic lethality effect. Selected hits' activity was validated, and the mechanism of the most potent candidate drug, AKT inhibitor AD5363 (capivasertib), on induction of the synthetic lethality with ARID1A deficiency was investigated.

RESULTS

After robust vulnerability screening of 551 diverse protein kinase inhibitors, we identified the AKT inhibitor AZD5363 as being the most potent lead compound in inhibiting viability of ARID1A-/- cells. A synthetic lethality between loss of ARID1A expression and AKT inhibition by AZD5363 was validated in both GC cell model system and xenograft model. Mechanistically, AZD5363 treatment induced pyroptotic cell death in ARID1A-deficient GC cells through activation of the Caspase-3/GSDME pathway. Furthermore, ARID1A occupied the AKT gene promoter and regulated its transcription negatively, thus the GC cells deficient in ARID1A showed increased expression and phosphorylation of AKT.

CONCLUSIONS

Our study demonstrates a novel synthetic lethality interaction and unique mechanism between ARID1A loss and AKT inhibition, which may provide a therapeutic and mechanistic rationale for targeted therapy on patients with ARID1A-defective GC who are most likely to be beneficial to AZD5363 treatment.

Characterization of alternative splicing events and prognostic signatures in gastric cancer

BACKGROUND

Accumulating evidences indicate that the specific alternative splicing (AS) events are linked to the occurrence and prognosis of gastric cancer (GC). Nevertheless, the impact of AS is still unclear and needed to further elucidation.

METHODS

The expression profile of GC and normal samples were downloaded from TCGA. AS events were achieved from SpliceSeq database. Cox regression together with LASSO analysis were employed to identify survival-associated AS events (SASEs) and calculate risk scores. PPI and pathway enrichment analysis were implemented to determine the function and pathways of these genes. Kaplan-Meier (K-M) analysis and Receiver Operating Characteristic Curves were used to evaluate the clinical significance of genes of SASEs. Q-PCR were applied to validate the hub genes on the survival prognosis in 47 GC samples. Drug sensitivity and immune cell infiltration analysis were conducted.

RESULTS

In total, 48 140 AS events in 10 610 genes from 361 GC and 31 normal samples were analyzed. Through univariate Cox regression, 855 SASEs in 763 genes were screened out. Further, these SASEs were analyzed by PPI and 17 hub genes were identified. Meanwhile, using Lasso and multivariate Cox regression analysis, 135 SASEs in 132 genes related to 7 AS forms were further screened and a GC prognostic model was constructed. K-M curves indicates that high-risk group has poorer prognosis. And the nomogram analysis on the basis of the multivariate Cox analysis was disclosed the interrelationships between 7 AS forms and clinical parameters in the model. Five key genes were then screened out by PPI analysis and Differential Expression Gene analysis based on TCGA and Combined-dataset, namely STAT3, RAD51B, SOCS2, POLE2 and TSR1. The expression levels of AS in STAT3, RAD51B, SOCS2, POLE2 and TSR1 were all significantly correlated with survival by qPCR verification. Nineteen drugs were sensitized to high-risk patients and eight immune cells showed significantly different infiltration between the STAD and normal groups.

CONCLUSIONS

In this research, the prognostic model constructed by SASEs can be applied to predict the prognosis of GC patients and the selected key genes are expected to become new biomarkers and therapeutical targets for GC treatment.

A shorter distal resection margin is a surrogate marker of nodal metastasis and poor prognosis in distal gastrectomy for advanced gastric cancer

BACKGROUND

Although a 3-5 cm surgical margin distance is recommended for advanced gastric cancer (GC) in Japanese guidelines, little is known about the clinical effects of the surgical margin, especially the distal resection margin (DM). This study aims to clarify the clinical significance of DM in GC.

METHODS

A total of 415 GC patients who underwent curative distal gastrectomy between 2008 and 2018 were analyzed retrospectively.

RESULTS

The DM significantly stratified recurrence-free survival (P = 0.002), and a DM < 30 mm was an independent factor of a poor prognosis (P = 0.023, hazard ratio: 1.91). Lymphatic recurrence occurred significantly more frequently in the DM < 30 mm group than in the DM ≥ 30 mm group (P = 0.019, 6.9% vs. 1.9%). Regarding the station No.6 lymph node metastases in advanced GC (DM < 30 mm vs. 30 mm ≤ DM ≤ 50 mm vs. DM > 50 mm), the number (P < 0.001, 1.42 ± 1.69 vs. 1.18 ± 1.80 vs. 0.18 ± 0.64), the positive rate (P < 0.001, 59.0% vs. 46.7% vs. 11.3%) and therapeutic value index (43.3 vs. 14.5 vs. 8.0) were significantly higher in the DM < 30 mm group. By subdivision using the DM distance of 30 mm, more segmented prognostic stratifications were possible (P < 0.001).

CONCLUSIONS

A DM of less than 30 mm could be a surrogate marker of poor RFS, especially increasing nodal recurrence. More intensive treatment strategies, including lymphadenectomy and chemotherapy, are needed for patients with this condition.

Development of nomograms for predicting the survival of intestinal-type gastric adenocarcinoma patients after surgery

Intestinal-type gastric adenocarcinoma (IGA) is a common phenotype of gastric cancer. Currently, few studies have constructed nomograms that may predict overall (OS) and cancer-specific survival (CSS) probability after surgery. This study is to establish novel nomograms for predicting the survival of IGA patients who received surgery. A total of 1814 IGA patients who received surgery between 2000 and 2018 were selected from Surveillance, Epidemiology, and End Results database and randomly assigned to the training and validating sets at a ratio of 7:3. Then univariate and multivariate cox regression analyses were performed to screen significant indictors for the construction of nomograms. The calibration curve, the area under the receiver operating characteristic (receiver operating characteristic, ROC) curve (the area under curve, AUC), C-index, net reclassification index (NRI), integrated discrimination improvement (IDI) and decision curve analysis (DCA) curves were applied to assess the performance of the model. The significant outcomes of multivariate analysis revealed that ten variables (age, sex, race, surgery type, summary stage, grade, AJCC TNM stage, radiotherapy, number of regional nodes examined, number of regional nodes positive) were demonstrated to construct the nomogram for OS and ten variables (age, sex, race, surgery type, summary stage, grade, AJCC TNM stage, chemotherapy, number of regional nodes examined, number of regional nodes positive) for CSS. The calibration and AUC uncovered their favorable predictive performance. Subsequently, C-index, NRI, IDI and DCA curves further validated the predicative superiority of nomograms over 7th AJCC Stage System. The validated nomogram provides more reliable OS and CSS predictions for postoperative IGA patients with good accuracy, which can help surgeons in treatment decision-making and prognosis evaluation.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

Characteristic of molecular subtype based on lysosome-associated genes reveals clinical prognosis and immune infiltration of gastric cancer

Background

Lysosome are involved in nutrient sensing, cell signaling, cell death, immune responses and cell metabolism, which play an important role in the initiation and development of multiple tumors. However, the biological function of lysosome in gastric cancer (GC) has not been revealed. Here, we aim to screen lysosome-associated genes and established a corresponding prognostic risk signature for GC, then explore the role and underlying mechanisms.

Methods

The lysosome-associated genes (LYAGs) were obtained from MSigDB database. Differentially expressed lysosome-associated genes (DE-LYAGs) of GC were acquired based on the TCGA database and GEO database. According to expression profiles of DE-LYAGs, we divided the GC patients into different subgroups and then explored tumor microenvironment (TME) landscape and immunotherapy response in LYAG subtypes using GSVA, ESTIMATE and ssGSEA algorithms. Univariate Cox regression analysis, LASSO algorithm and multivariate Cox regression analysis were adopted to identify the prognostic LYAGs and then establish a risk model for patients with GC. The Kaplan-Meier analysis, Cox regression analysis and ROC analysis were utilized to evaluate the performance of the prognostic risk model. Clinical GC specimens were also used to verify the bioinformatics results by qRT-PCR assay.

Results

Thirteen DE-LYAGs were obtained and utilized to distinguish three subtypes in GC samples. Expression profiles of the 13 DE-LYAGs predicted prognosis, tumor-related immunological abnormalities and pathway dysregulation in these three subtypes. Furthermore, we constructed a prognostic risk model for GC based on DEG in the three subtypes. The Kaplan-Meier analysis suggested that higher risk score related to short OS rate. The Cox regression analysis and ROC analysis indicated that risk model had independent and excellent ability in predicting prognosis of GC patients. Mechanistically, a remarkable difference was observed in immune cell infiltration, immunotherapy response, somatic mutation landscape and drug sensitivity. qRT-PCR results showed that compared with corresponding adjacent normal tissues, most screened genes showed significant abnormal expressions and the expression change trends were consistent with the bioinformatics results.

Conclusions

We established a novel signature based on LYAGs which could be served as a prognostic biomarker for GC. Our study might provide new insights into individualized prognostication and precision treatment for GC.

Construction of anoikis-related lncRNAs risk model: Predicts prognosis and immunotherapy response for gastric adenocarcinoma patients

Background: Anoikis acts as a programmed cell death that is activated during carcinogenesis to remove undetected cells isolated from ECM. Further anoikis based risk stratification is expected to provide a deeper understanding of stomach adenocarcinoma (STAD) carcinogenesis. Methods: The information of STAD patients were acquired from TCGA dataset. Anoikis-related genes were obtained from the Molecular Signatures Database and Pearson correlation analysis was performed to identify the anoikis-related lncRNAs (ARLs). We performed machine learning algorithms, including Univariate Cox regression and Least Absolute Shrinkage and Selection Operator (Lasso) analyses on the ARLs to build the OS-score and OS-signature. Clinical subgroup analysis, tumor mutation burden (TMB) detection, drug susceptibility analysis, immune infiltration and pathway enrichment analysis were further performed to comprehensive explore the clinical significance. Results: We established a STAD prognostic model based on five ARLs and its prognostic value was verified. Survival analysis showed that the overall survival of high-risk score patients was significantly shorter than that of low-risk score patients. The column diagrams show satisfactory discrimination and calibration. The calibration curve verifies the good agreement between the prediction of the line graph and the actual observation. TIDE analysis and drug sensitivity analysis showed significant differences between different risk groups. Conclusion: The novel prognostic model based on anoikis-related lncRNAs we identified could be used for prognosis prediction and precise therapy in gastric adenocarcinoma.

Does postoperative chemotherapy improve overall survival of patients with ypT1-2N0 cancer?

BACKGROUND

Perioperative chemotherapy combined with curative gastrectomy has been increasingly represented the standard therapeutic strategy for resectable gastric cancer (GC). However, it is still unclear whether postoperative chemotherapy has a survival benefit for ypT1-2N0 gastric cancer patients who have undergone preoperative chemotherapy followed curative gastrectomy.

METHODS

The data of patients who undergone neoadjuvant chemotherapy followed by gastrectomy and had pathological classification of ypT1-2N0 between March 2016 and December 2020 at Peking Union Medical College Hospital were retrospectively reviewed. Chi-square test was adopted to compare the difference between the patients with postoperative chemotherapy (pCHT) and without postoperative chemotherapy (no pCHT). Survival curves for overall survival (OS) were estimated using the Kaplan-Meier method, and the log-rank test was used to compare survival difference. Univariate and multivariate analyses for prognostic factors were based on the Cox regression.

RESULTS

A total of 134 patients met the inclusion criteria and 56 (41.8%) of them have undergone postoperative chemotherapy. There were no statistically significant differences in demographic and clinicopathologic characteristics between pCHT group and no pCHT group (all p > 0.05). Postoperative chemotherapy was not associated with a significant improvement in overall survival (OS) (Hazard ratio [HR] 0.815, 95% confidence interval [CI] 0.403-1.650; p = 0.474). Subgroup analyses demonstrated survival was equivalent between pCHT and no CHT group in ypT1N0 patients (HR 0.832, CI 0.222-3.121; p = 0.786) and ypT2N0 patients (HR 1.284, CI 0.564-2.924; p = 0.551). Multivariable analysis identified that clinical T stage independently influenced prognosis (cT3 vs. cT2: HR 2.875, 95% CI 0.998-8.281, p = 0.050; cT4 vs. cT2: HR 7.382, 95% CI 2.569-21.211, p < 0.001). In clinical T3-4 patients, there was an overall survival benefit for postoperative chemotherapy (HR 0.270, 95% CI 0.114-0.634; p = 0.006). No survival benefit of postoperative chemotherapy was identified in clinical T2 patients (HR 0.689, 95% CI 0.200-2.372; p = 0.579). Furthermore, postoperative chemotherapy was proved to be an independently positive prognostic factor for clinical T3-4 patients (HR 0.132, 95% CI 0.051-0.345; p < 0.001).

CONCLUSION

Postoperative chemotherapy might offer survival benefit to patients with ypT1-2N0 gastric cancer whose clinical T stage was T3-4 before preoperative chemotherapy.

Comparison of treatment strategies and survival of early-onset gastric cancer: a population-based study

Treatments for early-onset gastric cancer (EOGC) patients are rarely included in clinical trials, resulting in an unclear impact on survival. This study aimed to investigate the treatment patterns of EOGC patients and their impact on survival. Based on the Surveillance, Epidemiology, and End Results database, we conducted a retrospective analysis of 1639 EOGC patients (< 50 years) diagnosed between 2010 and 2018. Patients with larger tumours, distant metastasis, and AJCC TNM stage in IV were prone to receive nonsurgical treatment. Patients treated with surgery alone had a better prognosis than those receiving SROC or SCRT or nonsurgical treatment. However, analyses stratified by histological type, tumour size and TNM stage showed that patients did not benefit more from SROC and SCRT than from surgery alone. Similar results were observed in the stratified Cox regression risk analysis. Patients who received nonsurgical treatment had the highest risk of overall death [hazard ratio (HR) = 2.443, 95% confidence interval (CI) 1.865–3.200, P < 0.001]. This study indicated that additional radiotherapy, chemotherapy or chemoradiotherapy did not provide a coordinated survival benefit to EOGC patients.

Loss of ARID1A activates mTOR signaling and SOX9 in gastric adenocarcinoma-rationale for targeting ARID1A deficiency

BACKGROUND

Gastric adenocarcinoma (GAC) is a lethal disease with limited therapeutic options. Genetic alterations in chromatin remodelling gene AT-rich interactive domain 1A (ARID1A) and mTOR pathway activation occur frequently in GAC. Targeting the mechanistic target of rapamycin (mTOR) pathway in unselected patients has failed to show survival benefit. A deeper understanding of GAC might identify a subset that can benefit from mTOR inhibition.

METHODS

Genomic alterations in ARID1A were analysed in GAC. Mouse gastric epithelial cells from CK19-Cre-Arid1A^fl/fl and wild-type mice were used to determine the activation of oncogenic genes due to loss of Arid1A. Functional studies were performed to determine the significance of loss of ARID1A and the sensitivity of ARID1A-deficient cancer cells to mTOR inhibition in GAC.

RESULTS

More than 30% of GAC cases had alterations (mutations or deletions) of ARID1A and ARID1A expression was negatively associated with phosphorylation of S6 and SOX9 in GAC tissues and patient-derived xenografts (PDXs). Activation of mTOR signalling (increased pS6) and SOX9 nuclear expression were strongly increased in Arid1A^-/- mouse gastric tissues which could be curtailed by RAD001, an mTOR inhibitor. Knockdown of ARID1A in GAC cell lines increased pS6 and nuclear SOX9 and increased sensitivity to an mTOR inhibitor which was further amplified by its combination with fluorouracil both in vitro and in vivo in PDXs.

CONCLUSIONS

The loss of ARID1A activates pS6 and SOX9 in GAC, which can be effectively targeted by an mTOR inhibitor. Therefore, our studies suggest a new therapeutic strategy of clinically targeting the mTOR pathway in patients with GAC with ARID1A deficiency.

Prognostic value of small mother against decapentaplegic expression in human gastric cancer

Gastric cancer is the fifth most common malignancy in the world with alow 5-year survival rate. To date, no study has investigated the prognostic role of the small mother against decapentaplegic (SMAD) in gastric cancer. The association of SMADs with overall survival (OS) of gastric cancer was analyzed on the online Kaplan-Meier (KM) plotter database. Clinical data such as stage, differentiation, gender, treatment, and Her2 mutation status of gastric cancer patients were analyzed. The (E)-SIS3 was used to inhibit SMAD3 expression in gastric cancer cells, and the effects of SMAD3 on gastric cancer cells were analyzed via real-time cellular analysis (RTCA), flow cytometry, colony formation, and immunofluorescence assay. The results showed that the high expression of three members of SMADs (SMAD1, SMAD2, SMAD4) was correlated with afavorable OS of gastric cancer patients. Meanwhile, SMAD3 expression level indicated highly differentiated cancer. We also observed that surgical treatment was associated with high expression level of SMAD1 and SMAD2. Besides, the effect of Her2 on gastric cancer was not noticeable. Moreover, (E)-SIS3 pharmacological assay revealed that inhibition of expression of SMAD3 suppressed the proliferation and migration ability of gastric cancer cells via inducing apoptosis. Collectively, these results demonstrate that the high expression level of three members of SMADs (SMAD1, SMAD2, and SMAD4) is significantly correlated with favorable OS of gastric cancer patients, which is opposite to SMAD3. Thus, SMADs regulate the differentiation of cancer and can be used to guide treatment decisions.

Tumor Inhibitory Effect of Long Non-coding RNA LOC100505817 on Gastric Cancer

Gastric cancer (GC) is one of the major malignancies worldwide. Emerging evidence has revealed the potential involvement of long noncoding RNA (lncRNA) in human genetic disorders and cancer, but the role of LOC100505817 remains unknown. Thus, in this study, we isolated tissues from GC patients to characterize the functional importance of LOC100505817 in GC tumorigenesis. We also proposed a hypothesis that the regulation of Wnt/β-catenin pathway by LOC100505817 was regulated by miR-20a-mediated WT1. After the collection of cancer tissues and adjacent tissues were obtained from GC patients, expression of LOC100505817, Wnt/β-catenin pathway- and EMT-related genes was quantified. Ectopic expression and knockdown experiments were applied in order to investigate the protective role of LOC100505817 in the progression of GC. Subsequently, cell viability, flow cytometry for apoptosis and cell cycle were detected via CCK-8, while migration and invasion were determined using scratch test and Transwell assay respectively. Then interactions among LOC100505817, miR-20a and WT1 were explored by dual luciferase reporter gene assay, RNA pull down assay and RNA binding protein immunoprecipitation (RIP) assay. The results found poor expression LOC100505817 was poorly expressed in GC cells and tissues. Overexpressed LOC100505817 resulted in the significant reduction of cell proliferation, migration and invasion as well as the expression of Wnt2b, β-catenin, CyclinD1, N-cadherin, Vimentin and snail, while increased cell apoptosis along with the expression of E-cadherin. Wnt/β-catenin pathway and EMT in GC cells were suppressed by LOC100505817 through miR-20a-inhibted WT1. In summary, our results provided evidence suggesting that LOC100505817 inhibits GC through LOC100505817-mediated inhibition of Wnt/β-catenin pathway, that leads to the overall restraining of GC cell proliferation, migration and invasion through miR-20a-reduced WT1.

Identification and Construction of a Long Noncoding RNA Prognostic Risk Model for Stomach Adenocarcinoma Patients

Background

Long noncoding RNA-based prognostic biomarkers have demonstrated great potential in the diagnosis and prognosis of cancer patients. However, systematic assessment of a multiple lncRNA-composed prognostic risk model is lacking in stomach adenocarcinoma (STAD). This study is aimed at constructing a lncRNA-based prognostic risk model for STAD patients.

Methods

RNA sequencing data and clinical information of STAD patients were retrieved from The Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DElncRNAs) were identified using the R software. Univariate and multivariate Cox regression analyses were performed to construct a prognostic risk model. The survival analysis, C-index, and receiver operating characteristic (ROC) curve were employed to assess the sensitivity and specificity of the model. The results were verified using the GEPIA online tool and our clinical samples. Pearson correlation coefficient analysis, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed to indicate the potential biological functions of the selected lncRNA.

Results

A total of 1917 DElncRNAs were identified from 343 cases of STAD tissues and 30 cases of noncancerous tissues. According to univariate and multivariable Cox regression analyses, four DElncRNAs (AC129507.1, LINC02407, AL022316.1, and AP000695.2) were selected to establish a prognostic risk model. There was a significant difference in the overall survival between high-risk patients and low-risk patients based on this risk model. The C-index of the model was 0.652. The area under the curve (AUC) for the ROC curve was 0.769. GEPIA results confirmed the expression and prognostic significance of AP000695.2 in STAD. Our clinical data confirmed that upregulated expression of AP000695.2 was correlated with the T stage, distant metastasis, and TNM stage in STAD. GO and KEGG analyses demonstrated that AP000695.2 was closely related to the tumorigenesis process.

Conclusions

In this study, we constructed a lncRNA-based prognostic risk model for STAD patients. Our study will provide novel insight into the diagnosis and prognosis of STAD patients.

The Effectiveness of Postoperative Chemotherapy on pT1bN0 and pT2N0 Gastric Cancer Patients with Risk Factors: An International Dual-Center Analysis

PURPOSE

This study aimed to investigate the effectiveness of postoperative chemotherapy in pT1bN0 and pT2N0 gastric cancer patients with high risk factors.

MATERIALS AND METHODS

Clinicopathological data of gastric cancer patients, who had undergone gastrectomy in high volume centers in Korea and China and were finally diagnosed with pT1bN0 and pT2N0 between 2006 and 2010, were analyzed retrospectively. Survival analyses stratified by risk factors and multivariable analyses were performed.

RESULTS

A total of 1509 patients were enrolled, with 41 (2.7%) patients receiving adjuvant chemotherapy after gastrectomy and 1468 (97.3%) patients undergoing surgery alone. The adjuvant chemotherapy group showed higher percentages of tumor with maximal diameter >3 cm (51.2% vs. 25.8%), poor differentiation (68.3% vs. 49.8%), and less harvested lymph nodes (17.1% vs. 5.2%) compared to the surgery alone group. The overall survival rates were 95.1% in the adjuvant chemotherapy group and 93.3% in the surgery alone group, without significant difference. In multivariable analysis, age was found to be an independent prognostic factor. However, there were no difference in the overall survival between patients with risk factors and those without risk factors, even in terms of age. Meanwhile, patients with more than two risk factors who received chemotherapy showed better survival trend, especially for pT2N0 patients, compared to the surgery alone group, although no significant differences were observed.

CONCLUSION

In pT1bN0 and pT2N0 patients, age was found to be an independent prognostic factor. However, adjuvant chemotherapy seemed to be unnecessary, while postoperative chemotherapy might offer survival benefits to pT2N0 patients with more than two risk factors.

Intratumoral and Peritumoral Radiomics of Contrast-Enhanced CT for Prediction of Disease-Free Survival and Chemotherapy Response in Stage II/III Gastric Cancer

Background

We evaluated the ability of radiomics based on intratumoral and peritumoral regions on preoperative gastric cancer (GC) contrast-enhanced CT imaging to predict disease-free survival (DFS) and chemotherapy response in stage II/III GC.

Methods

This study enrolled of 739 consecutive stage II/III GC patients. Within the intratumoral and peritumoral regions of CT images, 584 total radiomic features were computed at the portal venous-phase. A radiomics signature (RS) was generated by using support vector machine (SVM) based methods. Univariate and multivariate Cox proportional hazards models and Kaplan-Meier analysis were used to determine the association of the RS and clinicopathological variables with DFS. A radiomics nomogram combining the radiomics signature and clinicopathological findings was constructed for individualized DFS estimation.

Results

The radiomics signature consisted of 26 features and was significantly associated with DFS in both the training and validation sets (both P<0.0001). Multivariate analysis showed that the RS was an independent predictor of DFS. The signature had a higher predictive accuracy than TNM stage and single radiomics features and clinicopathological factors. Further analysis showed that stage II/III patients with high scores were more likely to benefit from adjuvant chemotherapy.

Conclusion

The newly developed radiomics signature was a powerful predictor of DFS in GC, and it may predict which patients with stage II and III GC benefit from chemotherapy.

Chemotherapy Use and Survival Among Young and Middle-Aged Patients With Gastric Cancer

INTRODUCTION:

Treatments for young patients with gastric cancer (GC) remain poorly defined, and their effects on survival are uncertain. We aimed to investigate the receipt of chemotherapy by age category (18–49, 50–64, and 65–85 years) and explore whether age differences in chemotherapy matched survival gains in patients with GC.

METHODS:

Patients who were histologically diagnosed with GC were included from a Chinese multi-institutional database and the Surveillance, Epidemiology, and End Results database. There were 5,122 and 31,363 patients aged 18–85 years treated between 2000 and 2014, respectively. Overall survival and stage-specific likelihood of receiving chemotherapy were evaluated.

RESULTS:

Of the 5,122 and 31,363 patients in China and Surveillance, Epidemiology, and End Result data sets, 3,489 (68.1%) and 18,115 (57.8%) were men, respectively. Younger (18–49 years) and middle-aged (50–64 years) patients were more likely to receive chemotherapy compared with older patients (65–85 years) (64.9%, 56.7%, and 45.4% in the 3 groups from the China data set). Among patients treated with surgery alone, a significantly better prognosis was found in younger and middle-aged patients than their older counterparts; however, no significant differences were found in overall survival among age subgroups in patients who received both surgery and chemotherapy, especially in the China data set. The survival benefit from chemotherapy was superior among older patients (all P < 0.0001) compared with that among younger and middle-aged patients in stage II and III disease.

DISCUSSION:

Potential overuse of chemotherapy was found in younger and middle-aged patients with GC, but the addition of chemotherapy did not bring about matched survival improvement, especially in the China data set.

Magnesium-dependent Phosphatase (MDP) 1 is a Potential Suppressor of Gastric Cancer

BACKGROUND

Recurrence is the leading cause of treatment failure and death in patients with gastric cancer (GC). However, the mechanism underlying GC recurrence remains unclear, and prognostic markers are still lacking.

METHODS

We analyzed DNA methylation profiles in gastric cancer cases with shorter survival (<1 year) or longer survival (> 3 years), and identified candidate genes associated with GC recurrence. Then, the biological effects of these genes on gastric cancer were studied.

RESULTS

A novel gene, magnesium-dependent phosphatase 1 (mdp1), was identified as a candidate gene whose DNA methylation was higher in GC samples from patients with shorter survival and lower in patients with longer survival. MDP1 protein was highly expressed in GC tissues with longer survival time, and also had a tendency to be expressed in highly differentiated GC samples. Forced expression of MDP1 in GC cell line BGC-823 inhibited cell proliferation, whereas the knockdown of MDP1 protein promoted cell growth. Overexpression of MDP1 in BGC-823 cells also enhanced cell senescence and apoptosis. Cytoplasmic kinase protein c-Jun N-terminal kinase (JNK) and signal transducer and activator of transcription 3 (Stat3) were found to mediate the biological function of MDP1.

CONCLUSION

These results suggest that MDP1 protein suppresses the survival of gastric cancer cells and loss of MDP expression may benefit the recurrence of gastric cancer.

The synergistic anti-tumor effect of schisandrin B and apatinib

The synergistic anti-tumor effect of schisandrin B (Sch.B) and apatinib was investigated in vitro. The CCK-8 assay revealed that Sch.B enhanced the inhibition of apatinib on cell proliferation by arresting cell cycle in G0/G1 phase. Sch.B also potentiated the suppression of apatinib on cell migration and invasion, by means of wound-healing and transwell invasion assay. Flow cytometry results showed that Sch.B enhanced apoptosis induced by apatinib. The results were confirmed by western blot analysis of the proteins MMP-9, and Bax caspase-9, and -12. These results suggest that combining apatinib and Sch.B is an effective therapeutic strategy for preventing GC progression. [Formula: see text].

The clinical effect of Kampo medicine in multimodal treatment for Gastrointestinal Cancer in Japan

Kampo medicine or Japanese/Chinese traditional herbal medicine has long been used for the treatment of various diseases, mainly in Asian countries. In recent years, Asian investigators have attempted to clarify the mechanism and clinical efficacy of Kampo medicine. This review summarizes the background, current status, and future perspectives of Kampo medicine in the multimodal treatment of gastrointestinal cancer. Regarding the clinical effect of Kampo medicine on postoperative dysfunction after gastrointestinal surgery, several investigators have reported that Daikenchuto (TJ-100) had clinical efficacy after abdominal digestive surgery. The administration of TJ-100 during the immediate postoperative period after esophageal cancer surgery, gastric cancer surgery, and liver cancer surgery appeared to promote early recovery of the postoperative bowel function. Regarding Kampo medicine for chemotherapy-induced adverse effects in gastrointestinal cancer, promising results have been obtained for Hangeshashinto (TJ-14) and Goshajinkigan (TJ-107). The addition of TJ-14 might be associated with an improvement in the duration of chemotherapy-induced oral mucositis, and the addition of TJ-107 might be associated with an improvement in oxaliplatin-induced peripheral neurotoxicity. However, while several clinical trials have shown the positive results of Kampo medication for gastrointestinal cancer treatment, the clinical effects of such medicines have been limited. Further trials to investigate the clinical benefits of Kampo medicine are needed.

Management and prognostic prediction of appendiceal mucinous adenocarcinoma with peritoneal metastasis: a single center study in China

Background

To investigate the clinical and pathological characteristics of appendiceal mucinous adenocarcinoma with peritoneal metastasis and analyze the prognostic factors.

Methods

A retrospective analyses of clinicopathological features of 50 patients with appendiceal mucinous adenocarcinoma with peritoneal metastasis from January, 2013 to December, 2017 in Aerospace Central Hospital, Beijing, China. Survival data calculation and comparison were respectively performed with the Kaplan-Meier method and the log-rank test. The Cox proportional hazards regression method was used for multivariate survival analyses.

Results

Cytoreduction for appendiceal mucinous adenocarcinoma was conducted on 50 patients (24 males and 26 females), with a median age of 52.5 years at the time of surgery (range 31–71 years). The median overall survival (OS) time was 24 months, with 2-,3- and 5-year survival rates of 53, 24 and 8%, respectively. At the last follow-up in December 2018, 13 patients were still alive. Multivariate analysis revealed that patients who had low Ki-67 expression (less than 50%) and CCR (completeness of cytoreduction) 0/1/2 score had significantly better OS rate than their respective counterparts.

Conclusions

Ki-67 expression statue and CCR score could be employed as the prognosis prediction in patients with appendiceal mucinous adenocarcinoma.

Nomogram for predicting the survival of gastric adenocarcinoma patients who receive surgery and chemotherapy

Background

Surgery is the only way to cure gastric adenocarcinoma (GAC), and chemotherapy is the basic adjuvant management for GAC. A significant prognostic nomogram for predicting the respective disease-specific survival (DSS) rates of GAC patients who receive surgery and chemotherapy has not been established.

Objective

We were planning to establish a survival nomogram model for GAC patients who receive surgery and chemotherapy.

Methods

We identified 5764 GAC patients who had received surgery and chemotherapy from the record of Surveillance, Epidemiology, and End Results (SEER) database. About 70% (n = 4034) of the chosen GAC patients were randomly assigned to the training set, and the rest of the included ones (n = 1729) were assigned to the external validation set. A prognostic nomogram was constructed by the training set and the predictive accuracy of it was validated by the validation set.

Results

Based on the outcome of a multivariate analysis of candidate factors, a nomogram was developed that encompassed age at diagnosis, number of regional lymph nodes examined after surgery, number of positive regional lymph nodes, sex, race, grade, derived AJCC stage, summary stage, and radiotherapy status. The C-index (Harrell’s concordance index) of the nomogram model was some larger than that of the traditional seventh AJCC staging system (0.707 vs 0.661). Calibration plots of the constructed nomogram displayed that the probability of DSS commendably accord with the survival rate. Integrated discrimination improvement (IDI) revealed obvious increase and categorical net reclassification improvement (NRI) showed visible enhancement. IDI for 3-, 5- and 10- year DSS were 0.058, 0.059 and 0.058, respectively (P > 0.05), and NRI for 3-, 5- and 10- year DSS were 0.380 (95% CI = 0.316–0.470), 0.407 (95% CI = 0.350–0.505), and 0.413 (95% CI = 0.336–0.519), respectively. Decision curve analysis (DCA) proved that the constructed nomogram was preferable to the AJCC staging system.

Conclusion

The constructed nomogram supplies more credible DSS predictions for GAC patients who receive surgery and chemotherapy in the general population. According to validation, the new nomogram will be beneficial in facilitating individualized survival predictions and useful when performing clinical decision-making for GAC patients who receive surgery and chemotherapy.

The efficacy and feasibility of adopting intravenous chemotherapy and oral S-1 as a sequential therapy for postoperative gastric cancer patients

Some postoperative gastric cancer patients have to terminate systemic intravenous chemotherapy early due to adverse drug reactions. We performed a retrospective study to explore the efficacy and feasibility of sequential therapy.We retrospectively analyzed 55 postoperative gastric cancer patients (Group A) who received sequential therapy (intravenous chemotherapy and S-1) and 53 patients (Group B) who received intravenous chemotherapy from January 2012 to December 2013 in our hospital. The therapeutic effect (including 1-year, 5-year tumor recurrence and survival rate) and the incidence of adverse reactions were analyzed.When death and survival for more than 5 years was regarded as the end point of follow-up, the mean follow-up period was 40.6 months (34.7-46.4) in Group A and 39.2 months (33.0-45.3) in Group B. The 1-year tumor recurrence after the operation was 23.6% (13/55, Group A) and 28.3% (15/53, Group B). The 5-year tumor recurrence was 45.5% (25/55, Group A) and 49.1% (26/53, Group B). There was no significant difference in the 1- and 5-year tumor recurrence rates between these two groups (P > .05). The 1-year survival rates of Group A and Group B were 81.8% (45/55) and 79.2% (42/53), respectively, and the 5-year survival rates of Group A and Group B were 47.3% (26/55) and 45.3% (24/53), respectively. No significant difference was observed between these two treatments at either the 1- or 5-year survival benefit (P > .05). However, the patients in Group A had a lower incidence of gastrointestinal reactions (such as nausea and vomiting), leukopenia and liver function damage (P < .05). We also found that patients who underwent sequential therapy might show lower levels of adverse reactions.Our retrospective study provided some evidence to suggest that sequential treatment is effective and safe for postoperative gastric cancer patients who are intolerant to intravenous chemotherapy.

Induction/reversal of drug resistance in gastric cancer by non-coding RNAs (Review)

Gastric cancer (GC) is one of the most prevalent and malignant types of cancer worldwide. In China, it is the second most common type of cancer and the malignancy with the highest incidence and mortality rate. Chemotherapy for GC is not always effective due to the development of drug resistance. Drug resistance, which is frequently observed in GC, undermines the success rate of chemotherapy and the survival of patients with GC. The dysregulation of non‑coding RNAs (ncRNAs), primarily microRNAs (miRNAs or miRs) and long non‑coding RNAs (lncRNAs), is involved in the development of GC drug resistance via numerous mechanisms. These mechanisms contribute to the involvement of a large and complex network of ncRNAs in drug resistance. In this review, we focus on and summarize the latest research on the specific mechanisms of action of miRNAs and lncRNAs that modulate drug resistance in GC. In addition, we discuss future prospects and clinical applications of ncRNAs as potential targeted therapies against the chemoresistance of GC.

Mechanism of Viscum coloratum polysaccharide to regulate proliferation, migration, and invasion of gastric cancer cells

BACKGROUND

Gastric cancer (GC) is the fifth most common cancer globally and the third leading cause of cancer death. Traditional Chinese medicine treatment can alleviate patients' pain and improve postoperative recurrence. Viscum coloratum polysaccharide is one of the main anti-tumor active components of Viscum coloratum and can inhibit proliferation and induce apoptosis of cancer cells.

AIM

To investigate the effect of Viscum coloratum polysaccharide on the proliferation, migration, and invasion of human gastric cancer cells (SGC-7901) and the underlying mechanism.

METHODS

Viability of SGC-7901 cells treated with Viscum coloratum polysaccharide at 20 μg/mL, 40 μg/mL, 60 μg/mL, 80 μg/mL, and 100 μg/mL for 48 h was detected by MTT assay. Cell migration and invasion were detected by Transwell assays, and the protein expression of cyclin-dependent kinases 4 (CDK4), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), and nuclear factor κB (NF-κB) p65 in SGC-7901 cells was detected by Western blot.

RESULTS

Different concentrations of Viscum coloratum polysaccharide could inhibit the viability of SGC-7901 cells in a dose-dependent manner (P < 0.05). The results of Western blot indicted that the protein expression of CDK4, MMP-2, MMP-9, and NF-κB p65 in SGC-7901 cells treated with 100 μg/mL Viscum coloratum polysaccharide was down-regulated (P < 0.05), and Transwell assays showed that the numbers of migratory and invaded cells in the visual field were significantly decreased (P < 0.05).

CONCLUSION

Viscum coloratum polysaccharide may inhibit the proliferation, migration, and invasion of SGC-7901 cells by regulating the NF-κB signaling pathway and the expression of CDK4, MMP-2, and MMP-9 proteins.

Retracted Article: Long non-coding RNA GACAT1 alleviates doxorubicin and vincristine resistance through a PTEN/AKT/mTOR/S6K1 regulatory pathway in gastric cancer

Gastric cancer (GC) is a major global health problem. Chemotherapy is a common therapeutic strategy for cancers including GC. However, chemoresistance strikingly limits the clinical applications of chemotherapeutic drugs. Long non-coding RNAs (lncRNAs) have been widely reported to be implicated in the pathogenesis and chemoresistance of cancers including GC. Our work aims to investigate the roles and molecular mechanisms of lncRNA gastric cancer-associated transcript 1 (GACAT1) in regulating doxorubicin (ADR) and vincristine (VCR) resistance in GC. In this text, RT-qPCR assay showed that GACAT1 expression was markedly reduced in ADR- or VCR-resistant GC (SGC7901/ADR or SGC7901/VCR) cells and GC tissues. CCK-8 assay and flow cytometry analysis revealed that GACAT1 overexpression alleviated the resistance of GC cells to ADR and VCR. RT-qPCR and western blot assay disclosed that GACAT1 deactivated the AKT/mTOR/S6K1 signaling pathway and promoted PTEN expression in SGC7901/ADR or SGC7901/VCR cells. Restoration experiments demonstrated that GACAT1 attenuated ADR or VCR resistance by regulating the PTEN/AKT/mTOR/S6K1 pathway in SGC7901/ADR or SGC7901/VCR cells. In vivo experiments demonstrated that GACAT1 overexpression inhibited tumor growth and enhanced ADR- or VCR-mediated anti-tumor effects in GC xenograft tumor models. Taken together, these data revealed that GACAT1 weakened the resistance of GC cells to ADR and VCR by the PTEN/AKT/mTOR/S6K1 regulatory pathway in vitro and in vivo, shedding new light on GACAT1 upregulation as a potential strategy to alleviate chemoresistance in GC.

Gastric cancer (GC) is a major global health problem.

PTPRF as a novel tumor suppressor through deactivation of ERK1/2 signaling in gastric adenocarcinoma

Background

Protein tyrosine phosphatase, receptor type F (PTPRF) is an important phosphatase playing roles in regulating cell growth, differentiation and oncogenic transformation. Overexpression of PTPRF has been observed in non-small cell lung cancer, but its clinical significance in other malignancies is still unknown.

Methods

We explored the expression pattern of PTPRF in gastric adenocarcinoma by using RT-qPCR and immunohistochemistry staining. The clinical significance of PTPRF was evaluated by univariate and multivariate analyses. Furthermore, the signaling pathways downstream of PTPRF was investigated by knockdown and overexpression assays combined with cellular studies.

Results

We found a remarkable down-regulation of PTPRF in gastric adenocarcinomas, which was significantly associated with advanced tumor TNM stages. Survival analysis showed that lower PTPRF level indicated a poorer overall survival of gastric adenocarcinoma patients. By conducting knockdown and overexpression studies in gastric adenocarcinoma cells, we revealed the role of PTPRF on inhibiting extracellular signal-regulated kinase-1/2 (ERK1/2) phosphorylation and its downstream signaling. Consistent with clinical findings, cellular results demonstrated that overexpressing PTPRF can significantly inhibit tumor migration and invasion, while silencing PTPRF showed opposite effects.

Conclusion

In conclusion, patients with lower PTPRF expression in gastric adenocarcinoma tissues were more predisposed to advanced tumor stage and unfavorable prognosis.

Medical management of gastric cancer: a 2017 update

Gastric cancer remains a considerable health burden throughout the world. The Cancer Genome Atlas (TCGA) analysis has recently unveiled 4 genotypes of gastric cancer with data not ready to change treatment strategy yet. A multimodality approach to therapy is the cornerstone of screening, diagnosing, staging, treating and supporting patients with gastric cancer. The evidence-based approach to localized gastric cancer (>cT1b) is to use an either preoperative or postoperative strategy to maximize the benefit of surgery. The focus of future research is to optimize chemotherapy regimens, determine the role of radiation therapy and investigate the effect of treatment timing. In metastatic gastric cancer, biologic therapies have been introduced targeting markers shown to be prognostic. The results of ongoing randomized controlled phase 3 trials using targeted and immunotherapy agents, either in combination or alone, have the potential to alter the current treatment landscape of advanced gastric cancer.

Actionable gene-based classification toward precision medicine in gastric cancer

Background

Intertumoral heterogeneity represents a significant hurdle to identifying optimized targeted therapies in gastric cancer (GC). To realize precision medicine for GC patients, an actionable gene alteration-based molecular classification that directly associates GCs with targeted therapies is needed.

Methods

A total of 207 Japanese patients with GC were included in this study. Formalin-fixed, paraffin-embedded (FFPE) tumor tissues were obtained from surgical or biopsy specimens and were subjected to DNA extraction. We generated comprehensive genomic profiling data using a 435-gene panel including 69 actionable genes paired with US Food and Drug Administration-approved targeted therapies, and the evaluation of Epstein-Barr virus (EBV) infection and microsatellite instability (MSI) status.

Results

Comprehensive genomic sequencing detected at least one alteration of 435 cancer-related genes in 194 GCs (93.7%) and of 69 actionable genes in 141 GCs (68.1%). We classified the 207 GCs into four The Cancer Genome Atlas (TCGA) subtypes using the genomic profiling data; EBV (N = 9), MSI (N = 17), chromosomal instability (N = 119), and genomically stable subtype (N = 62). Actionable gene alterations were not specific and were widely observed throughout all TCGA subtypes. To discover a novel classification which more precisely selects candidates for targeted therapies, 207 GCs were classified using hypermutated phenotype and the mutation profile of 69 actionable genes. We identified a hypermutated group (N = 32), while the others (N = 175) were sub-divided into six clusters including five with actionable gene alterations: ERBB2 (N = 25), CDKN2A, and CDKN2B (N = 10), KRAS (N = 10), BRCA2 (N = 9), and ATM cluster (N = 12). The clinical utility of this classification was demonstrated by a case of unresectable GC with a remarkable response to anti-HER2 therapy in the ERBB2 cluster.

Conclusions

This actionable gene-based classification creates a framework for further studies for realizing precision medicine in GC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0484-3) contains supplementary material, which is available to authorized users.

Clinical significance of circulating tumor cells in blood from patients with gastric cancer

Circulating tumor cells (CTC) have been focused on as a target for detecting occult tumors, predicting therapeutic responses and prognoses, and monitoring postoperative recurrence in the clinical management of patients with various malignancies, including gastric cancer. Recent advances in molecular diagnostic tools have contributed to high sensitivity and specificity for the detection of CTC. A conspicuous disparity exists in the incidence of CTC among studies. However, a close relationship has been reported between positivity for CTC and well‐known prognostic clinicopathological factors including depth of tumor invasion, lymph node metastasis, stage, and lymphatic and venous invasion in patients with gastric cancer. According to most studies published on the clinical impact of CTC, the presence of CTC negatively affects the prognosis of patients with gastric cancer. Moreover, the study of CTC based on a meta‐analysis demonstrated their importance as a poor prognostic indicator. In clinical management, pre‐ and post‐therapeutic monitoring of CTC using liquid biopsy may be useful for early detection of subclinical patients or disease recurrence, prediction of tumor progression, and administrative control of adjuvant chemotherapy. Although their functional properties remain unclear, molecular profiling of CTC may contribute to the development of personalized treatment that effectively inhibits tumor progression in patients with advanced gastric cancer. We herein review the clinical significance of CTC as a promising blood marker and therapeutic target in patients with gastric cancer.

The Management and Prognostic Prediction of Adenocarcinoma of Appendix

Malignant tumours of the appendix are quite rare, especially appendiceal adenocarcinomas, which may be difficult to detect preoperatively or intraoperatively. We collected data for 1404 patients with adenocarcinoma of the appendix from the Surveillance, Epidemiology, and End Results Program (SEER) database to explore the potential associations between clinicopathological factors and overall survival. Furthermore, a novel nomogram for predicting prognosis was developed based on our analysis of the SEER data. The nomogram prediction model included seven prognostic factors derived based on different clinical estimates. When compared with the traditional tumour-node-metastasis (TNM) staging system, the nomogram prediction model showed superior discriminatory power (Harrell’s C-index, 0.741 vs. 0.686) and a greater degree of similarity to actual 5-year overall survival after calibration (Akaike Information Criterion index, 5270.781 vs. 5430.141). Finally, we provide recommendations for the management of patients with adenocarcinoma of the appendix. Notably, we found the depth of adenocarcinoma invasion may be used as an indicator to determine the optimal surgical approach. For mucinous adenocarcinomas of the appendix, because these tumours are characterized by unique biological behaviour, intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) is recommended. However, whether systematic chemotherapy should be administered to patients with adenocarcinoma of the appendix requires further investigation.