Development of MRI-Based Deep Learning Signature for Prediction of Axillary Response After NAC in Breast Cancer.

RATIONALE AND OBJECTIVES: To develop a MRI-based deep learning signature for predicting axillary response after neoadjuvant chemotherapy (NAC) in breast cancer (BC) patients. MATERIALS AND METHODS: We enrolled 327 BC patients with axillary lymph node (ALN) metastases receiving axillary operations after NAC. The deep learning features were extracted by ResNet34, which was pretrained by a large, well-annotated dataset from ImageNet. Then we identified deep learning radiomics on magnetic resonance imaging with dynamic contrast enhancement (DCE-MRI) in predicting axillary response after NAC in BC patients. RESULTS: The extraction of 128 deep learning radiomics (DLR) features relied on the DCE-MRI for each patient. After the least absolute shrinkage and selection operator regression analysis, 13, 8, and 21 features remained from the pre-treatment, post-treatment, and combined DCE-MRI, respectively. The DLR signature established based on the combined DCE-MRI achieved good capacity in ALN response after NAC. The support vector machine achieved the best performance with an 0.99 area under the curve (AUC) of (95% confidence interval (CI), 0.98-1.00) and 0.83 (95% CI, 0.73-0.92) in the training and test sets, respectively. The LR model established with clinical parameters represented the best performance with 0.73 AUC (95% CI, 0.62-0.84), 0.73 sensitivity, 0.73 specificity, 0.63 PPV, and 0.81 NPV in the test set, respectively. Finally, the integration of radiomic signature and clinical signature resulted in establishing a predictive radiomic nomogram, with an AUC of 0.99 (95%CI, 0.99-1.00). CONCLUSION: In conclusion, our current study constructed a predictive nomogram through the deep learning method, demonstrating favorable performance in the training and test cohort. The present prognostic model furnishes a precise and objective foundation for directing the surgical strategy toward ALN management in BC patients receiving NAC.

Identification of a six-gene signature to predict survival and immunotherapy effectiveness of gastric cancer.

Background: Gastric cancer (GC) ranks as the fifth most prevalent malignancy and the second leading cause of oncologic mortality globally. Despite staging guidelines and standard treatment protocols, significant heterogeneity exists in patient survival and response to therapy for GC. Thus, an increasing number of research have examined prognostic models recently for screening high-risk GC patients. Methods: We studied DEGs between GC tissues and adjacent non-tumor tissues in GEO and TCGA datasets. Then the candidate DEGs were further screened in TCGA cohort through univariate Cox regression analyses. Following this, LASSO regression was utilized to generate prognostic model of DEGs. We used the ROC curve, Kaplan-Meier curve, and risk score plot to evaluate the signature's performance and prognostic power. ESTIMATE, xCell, and TIDE algorithm were used to explore the relationship between the risk score and immune landscape relationship. As a final step, nomogram was developed in this study, utilizing both clinical characteristics and a prognostic model. Results: There were 3211 DEGs in TCGA, 2371 DEGs in GSE54129, 627 DEGs in GSE66229, and 329 DEGs in GSE64951 selected as candidate genes and intersected with to obtain DEGs. In total, the 208 DEGs were further screened in TCGA cohort through univariate Cox regression analyses. Following this, LASSO regression was utilized to generate prognostic model of 6 DEGs. External validation showed favorable predictive efficacy. We studied interaction between risk models, immunoscores, and immune cell infiltrate based on six-gene signature. The high-risk group exhibited significantly elevated ESTIMATE score, immunescore, and stromal score relative to low-risk group. The proportions of CD4+ memory T cells, CD8+ naive T cells, common lymphoid progenitor, plasmacytoid dentritic cell, gamma delta T cell, and B cell plasma were significantly enriched in low-risk group. According to TIDE, the TIDE scores, exclusion scores and dysfunction scores for low-risk group were lower than those for high-risk group. As a final step, nomogram was developed in this study, utilizing both clinical characteristics and a prognostic model. Conclusion: In conclusion, we discovered a 6 gene signature to forecast GC patients' OS. This risk signature proves to be a valuable clinical predictive tool for guiding clinical practice.

Radiomic model based on magnetic resonance imaging for predicting pathological complete response after neoadjuvant chemotherapy in breast cancer patients.

Purpose: To establish a model combining radiomic and clinicopathological factors based on magnetic resonance imaging to predict pathological complete response (pCR) after neoadjuvant chemotherapy in breast cancer patients. Method: MRI images and clinicopathologic data of 329 eligible breast cancer patients from the Affiliated Hospital of Qingdao University from August 2018 to August 2022 were included in this study. All patients received neoadjuvant chemotherapy (NAC), and imaging examinations were performed before and after NAC. A total of 329 patients were randomly allocated to a training set and a test set at a ratio of 7:3. We mainly studied the following three types of prediction models: radiomic models, clinical models, and clinical-radiomic models. All models were evaluated using subject operating characteristic curve analysis and area under the curve (AUC), decision curve analysis (DCA) and calibration curves. Results: The AUCs of the clinical prediction model, independent imaging model and clinical combined imaging model in the training set were 0.864 0.968 and 0.984, and those in the test set were 0.724, 0.754 and 0.877, respectively. According to DCA and calibration curves, the clinical-radiomic model showed good predictive performance in both the training set and the test set, and we found that we had developed a more concise clinical-radiomic nomogram. Conclusion: We have developed a clinical-radiomic model by integrating radiomic features and clinical factors to predict pCR after NAC in breast cancer patients, thereby contributing to the personalized treatment of patients.

Identification and Validation of a Four-Gene Ferroptosis Signature for Predicting Overall Survival of Lung Squamous Cell Carcinoma.

Background: Lung squamous cell carcinoma (LUSC) represents 30% of all non-small cell lung carcinoma. Targeted therapy is not sufficient for LUSC patients because of the low frequency of targeted-effective mutation in LUSC whereas immunotherapy offers more options for patients with LUSC. We explored a ferroptosis-related prognostic signature that can potentially assess the prognosis and immunotherapy efficacy of LUSC patients. Methods: A total of 502 LUSC patients were downloaded from The Cancer Genome Atlas (TCGA). The external validation data were obtained from the Gene Expression Omnibus (GEO): GSE73403. Then, we identified the candidate genes and constructed the prognostic signature through the Cox survival regression analyses and least absolute shrinkage and selection operator (LASSO). Risk score plot, Kaplan-Meier curve, and ROC curve were used to assess the prognostic power and performance of the model. The CIBERSORT algorithm estimated the fraction of immune cell types. TIDE was utilized to predict the response to immunotherapy. IMvigor210 was used to explore the association between the risk scores and immunotherapy outcomes. A nomogram combined selected clinical characteristics, and the risk scores were constructed. Results: We screened 132 differentially expressed ferroptosis-related genes. According to KEGG and GO pathway analyses, these genes were mainly engaged in the positive regulation of cytokine production, cytokine metabolic process, and oxidoreductase activity. We then constructed a prognostic model via LASSO regression. The proportions of CD8+ T cells, CD4+ activated T cells, and follicular helper T cells were significantly different between low-risk and high-risk groups. TIDE algorithm indicated that low-risk LUSC patients might profit more from immune checkpoint inhibitors. The predictive value of the ferroptosis gene model in immunotherapy response was further confirmed in IMvigor210. Finally, we combined the clinical characteristics with a LASSO regression model to construct a nomogram that could be easily applied in clinical practice. Conclusion: We identified a prognostic model that provides an accurate and objective basis for guiding individualized treatment decisions for LUSC.

CCR10/CCL27 crosstalk regulates cell metastasis via PI3K-Akt signaling axis in non-small-cell lung cancer.

Previous research has shown that CCR10 acts as a vital oncogene in the progression of multiple malignancies. However, its effect on the treatment of non-small-cell lung cancer (NSCLC) has not been investigated. Current research examined the effect of CCR10 on the cellular survival and migration of NSCLC, and the modulation of cell death and found that the expression levels of CCR10 and CCL27 (ligand) were highly upregulated in human NSCLC tissue and cell lines, A549 and H157, compared with adjacent normal lung specimens. MTT and colony formation assays revealed that the blockage of CCR10 inhibited the multiplication and survival of A549 and H157 cells. Further study showed that metastasis-relevant VEGF-C/D, MMP-2/9, TIMP-1/2 were also regulated via CCR10 activation. Notably, increased NF-κB levels were detected in cells with activated CCR10, whereas the levels of NF-κB decreased in cells with blocked CCR10. Finally, the recovery of NF-κB expression counteracted the suppressive influence of CCR10 blockage on NSCLC cell survival, migration, and invasion. These results improved our knowledge understanding the molecular mechanisms of CCR10-CCL27 in progression of NSCLC.

Gastrointestinal-type chemotherapy prolongs survival in an atypical primary ovarian mucinous carcinoma: A case report.

BACKGROUND: Primary ovarian mucinous carcinoma is a rare histologic subtype of epithelial ovarian carcinoma and exhibits considerable morphologic overlap with secondary tumour. It is hard to differentiate primary from metastatic ovarian mucinous carcinoma by morphological and immunohistochemical features. Because of the histologic similarity between primary ovarian mucinous carcinoma and metastatic gastrointestinal carcinoma, it has been hypothesized that ovarian mucinous carcinomas might respond better to non-gynecologic regimens. However, the standard treatment of advanced ovarian mucinous carcinoma has not reached a consensus. CASE SUMMARY: A 56-year-old postmenopausal woman presented with repeated pain attacks in the right lower quadrant abdomen, accompanied by diarrhoea, anorexia, and weight loss for about 3 mo. The patient initially misdiagnosed as having gastrointestinal carcinoma because of similar pathological features. Based on the physical examination, tumour markers, imaging tests, and genetic tests, the patient was clinically diagnosed with ovary mucinous adenocarcinoma. Whether gastrointestinal-type chemotherapy or gynecologic chemotherapy was a favourable choice for patients with advanced ovarian mucinous cancer had not been determined. The patient received a chemotherapy regimen based on the histologic characteristics rather than the tumour origin. The patient received nine cycles of FOLFOX and bevacizumab. This was followed by seven cycles of bevacizumab maintenance therapy for 9 mo. Satisfactory therapeutic efficacy was achieved. CONCLUSION: The genetic analysis might be used in the differential diagnosis of primary ovarian mucinous carcinoma and non-gynecologic mucinous carcinoma. Moreover, primary ovarian mucinous carcinoma patients could benefit from gastrointestinal-type chemotherapy.

Association between levels of tumor-infiltrating lymphocytes in different subtypes of primary breast tumors and prognostic outcomes: a meta-analysis.

BACKGROUND: To investigate the impact of the elevation of tumor-infiltrating lymphocytes (TILs) in different molecular subtypes of primary breast cancer, i.e. each 10% increment of TILs and high-level TILs (TILs≥50%) in tumor, on overall survival (OS) and pathological complete response (pCR) and to compare the presentation of high-level TILs across these molecular subtypes. METHODS: Citation retrieval was performed in the PubMed, Cochrane Library, Embase and Web of Science databases. All statistical calculations were performed by the software of StataSE version 12.0. RESULTS: Twenty-two eligible clinical trials including 15,676 unique patients were included for meta-analysis. Each 10% increment of TILs significantly improved OS in human epidermal growth factor receptor 2 (HER2)-overexpression (pooled Hazard ratio (HR), 0.92; 95% CI, 0.89-0.95) and triple-negative (TN) (pooled HR, 0.90; 95% CI, 0.89-0.92) breast tumors but not in luminal tumor subtype (pooled HR, 1.06; 95% CI, 0.99-1.13). It was also associated with an increased pCR rate in breast cancers (pooled Odds ratio (OR), 1.27; 95% CI, 1.19-13.5). High-level TILs were significantly related with a higher pCR rate (pooled OR, 2.73; 95% CI, 2.40-3.01) than low-level TILs. The HER2-amplified (pooled OR, 3.14; 95% CI, 1.95-5.06) and TN (pooled OR, 4.09; 95% CI, 2.71-6.19) phenotypes of breast cancers expressed significantly more high-level TILs than the luminal tumor subtype, although the presentation of those between the former two subsets was not significantly different (pooled OR, 1.30; 95%CI, 0.83-2.04). CONCLUSIONS: The elevation of TILs in breast tumors predicts favorable prognostic outcomes, particularly in the HER2-overexpression and TN subtypes.

LncRNA TTN-AS1 Regulates miR-524-5p and RRM2 to Promote Breast Cancer Progression.

BACKGROUND: Recent studies suggest many long non-coding RNAs (lncRNAs) are crucial oncogenes or tumor suppressors. This study intended to investigate the biological function and mechanism of lncRNA TTN antisense RNA 1 (TTN-AS1) in the progression of breast cancer (BC). MATERIALS AND METHODS: BC tissue samples were collected. The expression of TTN-AS1 in BC tissues and adjacent tissues was detected by qRT-PCR, and the relationship between pathological indicators and TTN-AS1 expression was analyzed by chi-square test. BC cell lines T47D and BT549 were utilized as cell models. CCK-8 assay and BrdU assay were used to detect the effect of TTN-AS1 on BC cell proliferation. Transwell assay was used to detect the effects of TTN-AS1 on cell migration and invasion. In addition, dual-luciferase reporter gene assay was used to confirm the targeting relationship between miR-524-5p and TTN-AS1. Western blot was used to detect the function of TTN-AS1 on regulating ribonucleotide reductase subunit 2 (RRM2) and survivin. Additionally, subcutaneous xenotransplanted tumor model and tail vein injection model were constructed in vivo. RESULTS: The expression of TTN-AS1 in BC tissues was significantly higher than that in normal tissues, and its high expression was correlated with adverse pathological indicators. Overexpression of TTN-AS1 significantly promoted the proliferation, migration and invasion of BC cells. TTN-AS1 knockdown suppressed the malignant phenotypes of BC cells. TTN-AS1 overexpression significantly impeded the expression of miR-524-5p, but increased the expression of RRM2. CONCLUSION: TTN-AS1 exerts oncogenic function in BC by repressing miR-524-5p and increasing the expression of RRM2.

Quercetin radiosensitizes non-small cell lung cancer cells through the regulation of miR-16-5p/WEE1 axis.

BACKGROUND: Quercetin, a widely distributed bioflavonoid, plays a role in combating diverse human cancers including non-small cell lung cancer (NSCLC). However, the role of quercetin in reversing the radioresistance of NSCLC cells and its underlying mechanism are far from being elucidated. METHOD: Radiation-resistant NSCLC cell lines were established. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of miR-16-5p and WEE1 G2 checkpoint kinase (WEE1) mRNA in radiation-resistant cells. After being treated with different concentrations of quercetin and different doses of X-ray, cell proliferation and apoptosis were monitored by CCK-8 assay, colony formation assay, and flow cytometry, respectively. Ultimately, the targeting relationship between miR-16-5p and WEE1 was verified via a dual fluorescent reporter gene assay. RESULTS: The expression of miR-16-5p was down-regulated in radiation-resistant cells, while the expression of WEE1 was up-regulated. Quercetin enhanced the radiosensitivity of NSCLC cells in a dose- and time-dependent manner. Furthermore, quercetin treatment increased the expression of miR-16-5p and decreased the expression of WEE1. The function of quercetin was reversed by miR-16-5p inhibitors or the transfection of WEE1 overexpressing plasmids. CONCLUSION: In conclusion, quercetin enhanced the radiosensitivity of NSCLC cells via modulating the expression of miR-16-5p and WEE1.

The tumour response of postmenopausal hormone receptor-positive breast cancers undergoing different types of neoadjuvant therapy: a meta-analysis.

BACKGROUND: To investigate the efficacy of neoadjuvant chemotherapy (NCT), neoadjuvant endocrine therapy (NET) and neoadjuvant chemoendocrine therapy (NCET) on the tumour response, including pathological complete response (pCR) rate and overall response rate (ORR), in postmenopausal women with hormone receptor (HR)-positive breast cancer. METHODS: Based on a PRISMA-IPD statement, the PubMed, Embase and Cochrane Library databases were used to identify eligible trials published from inception to 7 May 2019. Pooled odds ratio (OR) with 95% confidential interval (CI) was calculated to assess the pCR rate and ORR of tumours among those three treatments via fixed- or random-effect Mantel-Haenszel models in terms of a Heterogeneity Chi2 test with a significant level of p < 0.1. All statistical tests were performed by the software of StataSE, version 12.0. RESULTS: The analysed data consisted of 10 eligible clinical trials with 971 unique HR-positive breast cancer patients. The pooled results indicated that the pCR rate of those patients undergoing NET was significantly lower than those undergoing NCT (pooled OR, 0.48; 95% CI, 0.26-0.90), whereas the difference of ORR between both therapies was not statistically significant (pooled OR, 1.05; 95% CI, 0.73-1.52). The combined paradigm of NCET compared with the monotherapy of NET or NCT did not present a significantly improved pCR rate or ORR (pooled OR, 2.61; 95% CI, 0.94-7.25; and 2.25; 95% CI, 0.39-13.05; respectively). CONCLUSION: Postmenopausal HR-positive breast cancer patients after NCT may have better tumour response than those after NET, while those undergoing NCET may not manifest the apparently improved clinical efficacies compared to those receiving monotherapy.

Do early HER2-overexpression breast cancer patients benefit from undergoing neoadjuvant trastuzumab and mastectomy? A meta-analysis.

PURPOSE: To assess the overall survival (OS) of early human epidermal growth factor receptor 2 (HER2)-enriched breast cancer patients after receiving neoadjuvant trastuzumab (NAT) compared to adjuvant trastuzumab (AT) treatment and the difference in local-regional relapse (LRR) rate with this tumor and treatment between women after mastectomy and women after breast-conserving therapy (BCT). METHODS: Articles were retrieved from PubMed, Embase, Web of Science, and Cochrane Library. A pooled odds ratio (OR) with a 95% confidential interval (CI) was calculated. The StataSE version 12.0 software was employed for meta-analysis. RESULTS: Twelve available clinical studies containing 2366 subjects were included. The OS of NAT compared with that of AT was not significantly different (pooled OR=1.04; 95% CI, 0.47-2.33). There was a significantly lower LRR rate for patients with mastectomy compared to those with BCT (pooled OR=0.58; 95% CI, 0.38-0.89); however, subgroup analysis revealed that the significant advantage of LRR for mastectomy compared to BCT was only represented in women without trastuzumab treatment (pooled OR=0.52; 95% CI, 0.31-0.88) compared to those who received trastuzumab treatment (pooled OR=0.71; 95% CI, 0.34-1.49). CONCLUSION: Early stage HER2-overexpression breast cancer patients benefit with an equivalent OS from NAT treatment compared to AT. Patients who underwent mastectomy and BCT experienced a similar LRR rate if they received anti-HER2 targeted therapy of trastuzumab, but the LRR rate was discernibly reduced in patients who received mastectomy compared to BCT if they did not also receive trastuzumab treatment.

The prognosis comparison of different molecular subtypes of breast tumors after radiotherapy and the intrinsic reasons for their distinct radiosensitivity.

Radiotherapy can increase the cell cycle arrest that promotes apoptosis, reduces the risk of tumor recurrence and has become an irreplaceable component of systematic treatment for patients with breast cancer. Substantial advances in precise radiotherapy unequivocally indicate that the benefits of radiotherapy vary depending on intrinsic subtypes of the disease; luminal A breast cancer has the highest benefit whereas human epidermal growth factor receptor 2 (HER2)-positive and triple negative breast cancer (TNBC) are affected to a lesser extent irrespective of the selection of radiotherapy strategies, such as conventional whole-breast irradiation (CWBI), accelerated partial-breast irradiation (APBI), and hypofractionated whole-breast irradiation (HWBI). The benefit disparity correlates with the differential invasiveness, malignance, and radiosensitivity of the subtypes. A combination of a number of molecular mechanisms leads to the strong radioresistant profile of HER2-positive breast cancer, and sensitization to irradiation can be induced by multiple drugs or compounds in luminal disease and TNBC. In this review, we aimed to summarize the prognostic differences between various subtypes of breast tumors after CWBI, APBI, and HWBI, the potential reasons for drug-enhanced radiosensitivity in luminal breast tumors and TNBC, and the robust radioresistance of HER2-positive cancer.

A systematic review of clinical outcomes and radiotherapy-associated toxicity in multicatheter accelerated partial breast irradiation.

BACKGROUND: To integrate relevant clinical data of multicatheter accelerated partial breast irradiation (mAPBI) for reaching a comprehensive conclusion. METHODS: We did 3 meta-analyses for clinical outcomes including 1740 women from 4 articles, for acute radiotherapy (RT)-associated toxicity including 1255 patients from 5 articles, and for late RT-related toxicity involving 1565 patients from 9 papers. Clinical outcomes analyses were stratified by molecular subtypes, lymph nodes status, receptor status, and human epidermal growth factor receptor 2 (HER2) status. RESULTS: For the Luminal A/B phenotypes, the disease relapse and failure in survival significantly decreased when compared with triple negative (TN)/HER2-amplified subtypes (P < .00001). The 5-year regional nodal recurrence (RNR), 5-year distant metastasis-free survival (DMFS) and 5-year disease free-survival (DFS) of TN patients were significantly superior to HER2-overexpression patients (P < .00001). The 5-year cause-specific survival (CSS), 5-year DMFS and 5-year overall survival (OS) in women with lymph nodes-negative were significantly improved versus patients with lymph nodes-positive (P = .0001). Conversely, the positive status of HER2 compared with negative one significantly increased the rate of local recurrence (LR) (P = .02). For acute toxicity, the morbidity of dermatitis was significantly higher than hematoma and implant infection (P = .01, P < .0001, respectively). For late toxicity, the occurrences of fibrosis (32%) and telangiectasia (14%) were significantly higher than other complications (P < .0001). CONCLUSION: HER2-enriched subtype compared with other subtypes has significantly increased disease relapse and failure in survival. HER2-positive status is positively associated with an increased incidence of LR. Dermatitis is the most common acute RT-related toxicity and fibrosis is the first rife late RT-related toxicity.

Prognostic and predictive value of HURP in non­small cell lung cancer.

Previous studies have revealed that HURP (also known as DLGAP5 or KIAA0008) is overexpressed in many types of human cancers, such as hepatocellular carcinoma, squamous cell bladder cancer, and transitional cell carcinoma, indicating that HURP is a putative oncoprotein that promotes carcinogenesis through various molecular mechanisms. However, the role of HURP in the pathogenesis of non­small cell lung cancer (NSCLC) has not been reported. In the present study, we investigated the prognostic value of HURP among NSCLC patients through the GEO database. The online tool of KM­plotter was used to identify the correlation of HURP expression and the survival of NSCLC patients. We found the HURP expression at the mRNA level was correlated with the clinicopathologic characteristics and prognosis of NSCLC patients. HURP was highly expressed in aggressive NSCLC cells, and its higher expression was associated with shorter survival. Further cytological experiments revealed that the silencing of HURP caused cell cycle arrest and inhibited the proliferation of NSCLC cells. Transwell assay showed that HURP shRNA inhibited cell migration and invasion in vitro. The bioinformatic analysis suggests that HURP promotes carcinogenesis in multiple manners. Taken together, we revealed the prognostic value of HURP in NSCLC patients and HURP may be a potential therapeutic target for NSCLC.

Downregulation of P-gp, Ras and p-ERK1/2 contributes to the arsenic trioxide-induced reduction in drug resistance towards doxorubicin in gastric cancer cell lines.

Multidrug resistance (MDR) to doxorubicin (DOX) limits its effectiveness against tumor cells. Arsenic trioxide (As2O3) has been reported to reduce MDR in various types of cancer, but the mechanisms involving Ras and p-glycoprotein (P-gp) remain to be fully elucidated. The objectives of the present study were to evaluate As2O3 in reversing MDR to DOX, and to identify the association in antitumor activities between the effectiveness of DOX and Ras/phosphorylated (p­) extracellular signal­regulated kinase (ERK)1/2 signaling in SGC7901/ADM and SGC7901/S human gastric cancer cell lines. Cytotoxicity and sensitivity towards As2O3 were assessed using non­toxic and mildly­toxic concentrations (0.1 and 0.5 µM, respectively). The reversing effect of As2O3 on MDR was investigated prior to and following treatment with a cytokine activation of the recombinant human granulocyte colony stimulating factor ERK pathway. The SGC7901/ADM and SGC7901/S cells had the same sensitivity to As2O3. The SGC7901/ADM cells were resistant to DOX and As2O3 treatment reduced the level of resistance to DOX (P<0.01). The expression of P­glycoprotein (P-gp) in the SGC7901/ADM cells was higher than in the SGC7901/S cells (P<0.001). As2O3 treatment decreased the levels of P­gp in a time­ and dose­dependent manner (P<0.01). The expression of Ras was higher in the SGC7901/ADM cells than in the SGC7901/S cells, while the expression of p­ERK1/2 remained the same. As2O3 decreased the levels of Ras and p­ERK1/2 (P<0.01). Following pretreatment with rhG­CSF, the levels of Ras and p­ERK1/2 were further decreased (P<0.01). Drug­resistant gastric cancer cells had higher expression levels of P­gp and Ras, but not of p­ERK1/2. Non­ and mildly­toxic doses of As2O3 reduced MDR to DOX through Ras/p-ERK1/2 signaling.

Secreted clusterin gene silencing enhances chemosensitivity of a549 cells to cisplatin through AKT and ERK1/2 pathways in vitro.

BACKGROUND/AIMS: Several studies have shown secreted clusterin (sCLU) silencing directed against sCLU mRNA in sCLU-rich lung cancer cell lines sensitized cells to chemotherapy. However, the molecular mechanisms underlying the effect of sCLU silencing on lung cancer cell chemosensitivity is not known. In the present study, we aimed to determine that vector expressing short hairpin RNA against sCLU RNA (sCLU-shRNA) enhances the chemosensitivity in human small cell lung cancer A549 cells in vitro by inhibition of phosphorylated ERK1/2 (p-ERK1/2) and Akt (p-Akt). METHODS: The pCDNA3.1-sCLU and control scrambled pCDNA3.1 plasmid was constructed. We investigated the effects of sCLU overexpression by pCDNA3.1-sCLU transfection on chemosensitivity to cisplatin (DDP) in A549 cells in vitro. We down-regulated sCLU expression by short hairpin RNA against sCLU RNA (sCLU-shRNA) and investigated the effects on chemosensitivity to DDP in A549 cells and A549(DDP)in vitro. In order to confirm the correlation between sCLU and AKT and ERK1/2 signals, cells were treated with wortmannin and U0126. RESULTS: We found the chemotherapeutic agent DDP activated sCLU. Overexpression of sCLU increased cellular DDP chemoresistance in the A549(DDP) and pCDNA3. 1-sCLU transfected A549 cells via inhibition DDP-induced apoptosis. Whereas sCLU knockdown induced chemosensitization in the S549 and A549(DDP) cells via increase of DDP-induced apoptosis. sCLU overexpression activated pAKT Ser(473) and pERK1/2(Thr202/Tyr204), and vice versa. Inhibition of pAKT Ser(473) and pERK1/2(Thr202/Tyr204) was sufficient to induce significant recover y in chemosensitivity to DDP in A549(DDP) in the presence of sCLU overexpression. The DDP activated sCLU, which directly regulated pAKT and pERK1/2. CONCLUSIONS: This novel finding suggests that therapies directed against sCLU and its downstream signaling targets pAKT and pERK1/2 may have the potential to enhance the efficacy of DDP-based chemotherapy.