MicroRNAs are involved in the development and progression of gastric cancer.

MicroRNAs (miRNAs) are recognized as an essential component of the RNA family, exerting multiple and intricate biological functions, particularly in the process of tumorigenesis, proliferation, and metastatic progression. MiRNAs are altered in gastric cancer (GC), showing activity as both tumor suppressors and oncogenes, although their true roles have not been fully understood. This review will focus upon the recent advances of miRNA studies related to the regulatory mechanisms of gastric tumor cell proliferation, apoptosis, and cell cycle. We hope to provide an in-depth insight into the mechanistic role of miRNAs in GC development and progression. In particular, we summarize the latest studies relevant to miRNAs' impact upon the epithelial-mesenchymal transition, tumor microenvironment, and chemoresistance in GC cells. We expect to elucidate the molecular mechanisms involving miRNAs for better understanding the etiology of GC, and facilitating the development of new treatment regimens for the treatment of GC.

CRISPR/Cas9 ablating viral microRNA promotes lytic reactivation of Kaposi's sarcoma-associated herpesvirus.

The CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated gene 9) system is an RNA-guided, DNA editing method that has been widely used for gene editing, including human viruses. Kaposi's sarcoma-associated herpesvirus (KSHV/HHV8), following latent infection in human cells, can cause a variety of malignancies, such as Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD), with a high prevalence in immunocompromised patients. Of significant concern, the latent infection with KSHV has been shown to lead to increased resistance to antiviral therapies. MicroRNAs (miRNAs) are a set of non-coding, small RNA molecules that regulate protein-coding genes at the post-transcriptional and translational levels. KSHV has its miRNAs, most of which are expressed in latently infected cells and play a crucial role in maintaining KSHV latency. Notably, by regulating the expression of the downstream target genes in host cells, KSHV miRNAs can interact with the host environment to promote the development of KSHV-related diseases. Although CRISPR/Cas9 has been reported to edit KSHV protein-coding genes, there is no published literature on whether the CRISPR/Cas9 system can regulate the expression of KSHV miRNAs. In this study, we used CRISPR/Cas9 to inhibit the expression of KSHV miRNAs by directly editing the DNA sequences of individual KSHV miRNAs, or the promoter of clustered KHSV miRNAs, in latent KSHV-infected PEL cells. Our results show that CRISPR/Cas9 can ablate KSHV miRNAs expression, which in turn leads to the upregulation of viral lytic genes and alteration of host cellular gene expression. To the best of our knowledge, our study is the first reported demonstration of the CRISPR/Cas9 system editing KSHV miRNAs, further expanding the application of CRISPR/Cas9 as a novel antiviral strategy targeting KSHV latency.

Metformin and cancer immunity.

The immune system plays an essential and central role in tumor cell differentiation, proliferation, angiogenesis, apoptosis, invasion, and metastasis. Over the past decade, cancer therapy has rapidly evolved from traditional approaches, such as surgery, chemotherapy, and radiotherapy, to revolutionary new treatment options with immunotherapy. This new era of cancer treatment options has now been clinically tested and applied to many forms of human malignancies, often with quite dramatic results. As we develop more effective combinations of cancer treatment, several agents have been recently investigated, putatively identified as anticancer agents, or immunostimulatory molecules. One such agent is metformin, originally developed as a fairly standard first-line therapy for patients with type-2 diabetes mellitus (T2DM). Given the underlying mechanisms of action, researchers began to examine the alternative functions and possible utility of metformin, finding that the cancer risk in patients with T2DM was reduced. It appears that metformin, at least in part, has an antitumor effect through activation of the 5' adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Moreover, numerous studies have demonstrated that metformin interferes with key immunopathological mechanisms that are involved in the pathological processes or associated with malignant progression. Such insights may shed light on further analyzing whether metformin enhances the effectiveness of the immunotherapy and overcomes the immunotherapy resistance in the patients. Herein, we provide a comprehensive review of the literature examining the impact of metformin upon the host immune system and cancer immunity.

Development of Effective Therapeutics Targeting HER3 for Cancer Treatment.

HER3 is the third member of the human epidermal growth factor receptor (HER/EGFR) family, and unlike its other family members, is unique due to its minimal intrinsic kinase activity. As a result, HER3 has to interact with another receptor tyrosine kinase (RTK), such as EGFR or HER2, in order to activate the PI-3 K/Akt, MEK/MAPK, Jak/Stat pathways, as well as Src kinase. Over-expression of HER3 in various human cancers promotes tumor progression by increasing metastatic potential and acting as a major cause of treatment failure. Effective inhibition of HER3, and/or the key downstream mediators of HER3 signaling, is thought to be required to overcome resistance and enhance therapeutic efficacy. To date, there is no known HER3-targeted therapy that is approved for breast cancer, with a number of anti-HER3 antibodies current in various stages of development and clinical testing. Recent data suggests that the epigenetic strategy of using a histone deacetylase (HDAC) inhibitor, or functional cooperative miRNAs, may be an effective way to abrogate HER3 signaling. Here, we summarize the latest advances in our understanding of the mechanism of HER3 signaling in tumor progression, with continuing research towards the identification of therapeutic anti-HER3 antibodies. We will also examine the potential to develop novel epigenetic approaches that specifically target the HER3 receptor, along with important key downstream mediators that are involved in cancer treatment.

A novel patient-derived xenograft model for claudin-low triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) subtypes are clinically aggressive and cannot be treated with targeted therapeutics commonly used in other breast cancer subtypes. The claudin-low (CL) molecular subtype of TNBC has high rates of metastases, chemoresistance and recurrence. There exists an urgent need to identify novel therapeutic targets in TNBC; however, existing models utilized in target discovery research are limited. Patient-derived xenograft (PDX) models have emerged as superior models for target discovery experiments because they recapitulate features of patient tumors that are limited by cell-line derived xenograft methods. METHODS: We utilize immunohistochemistry, qRT-PCR and Western Blot to visualize tumor architecture, cellular composition, genomic and protein expressions of a new CL-TNBC PDX model (TU-BcX-2O0). We utilize tissue decellularization techniques to examine extracellular matrix composition of TU-BcX-2O0. RESULTS: Our laboratory successfully established a TNBC PDX tumor, TU-BCX-2O0, which represents a CL-TNBC subtype and maintains this phenotype throughout subsequent passaging. We dissected TU-BCx-2O0 to examine aspects of this complex tumor that can be targeted by developing therapeutics, including the whole and intact breast tumor, specific cell populations within the tumor, and the extracellular matrix. CONCLUSIONS: Here, we characterize a claudin-low TNBC patient-derived xenograft model that can be utilized for therapeutic research studies.

Clinical Utility of the 12-Gene DCIS Score Assay: Impact on Radiotherapy Recommendations for Patients with Ductal Carcinoma In Situ.

OBJECTIVE: The aim of this study was to determine the impact of the results of the 12-gene DCIS Score assay on (i) radiotherapy recommendations for patients with pure ductal carcinoma in situ (DCIS) following breast-conserving surgery (BCS), and (ii) patient decisional conflict and state anxiety. METHODS: Thirteen sites across the US enrolled patients (March 2014-August 2015) with pure DCIS undergoing BCS. Prospectively collected data included clinicopathologic factors, physician estimates of local recurrence risk, DCIS Score results, and pre-/post-assay radiotherapy recommendations for each patient made by a surgeon and a radiation oncologist. Patients completed pre-/post-assay decisional conflict scale and state-trait anxiety inventory instruments. RESULTS: The analysis cohort included 127 patients: median age 60 years, 80 % postmenopausal, median size 8 mm (39 % ≤5 mm), 70 % grade 1/2, 88 % estrogen receptor-positive, 75 % progesterone receptor-positive, 54 % with comedo necrosis, and 18 % multifocal. Sixty-six percent of patients had low DCIS Score results, 20 % had intermediate DCIS Score results, and 14 % had high DCIS Score results; the median result was 21 (range 0-84). Pre-assay, surgeons and radiation oncologists recommended radiotherapy for 70.9 and 72.4 % of patients, respectively. Post-assay, 26.4 % of overall recommendations changed, including 30.7 and 22.0 % of recommendations by surgeons and radiation oncologists, respectively. Among patients with confirmed completed questionnaires (n = 32), decision conflict (p = 0.004) and state anxiety (p = 0.042) decreased significantly from pre- to post-assay. CONCLUSIONS: Individualized risk estimates from the DCIS Score assay provide valuable information to physicians and patients. Post-assay, in response to DCIS Score results, surgeons changed treatment recommendations more often than radiation oncologists. Further investigation is needed to better understand how such treatment changes may affect clinical outcomes.

Male Breast Cancer With Dual BRCA2 and BRIP1 Deleterious Gene Mutations.

Background: Male breast cancer remains relatively underexplored in the medical literature. At present, male patients with breast cancer follow the same treatment guidelines as female patients with breast cancer, principally because of similar outcomes with treatment. However, this practice should not preclude generating evidence for male breast cancer surveillance, diagnosis, and management. BRCA2 gene mutations are associated with an increased risk of male breast cancer, along with lesser-known gene mutations that could also increase this risk, such as mutations of the BRIP1 gene. This case report presents a male patient with dual BRCA2 and BRIP1 deleterious gene mutations. To our knowledge, this combination has not been reported in the medical literature to date. Case Report: A 53-year-old male presented with a palpable symptomatic mass underneath the right nipple-areolar complex. Biopsies confirmed a poorly differentiated, infiltrating ductal carcinoma that was estrogen and progesterone receptor positive and human epidermal growth factor receptor-2 negative. The patient underwent a left modified radical mastectomy, with a right prophylactic simple mastectomy. Postoperatively, he underwent adjuvant chemotherapy and endocrine therapy. Conclusion: This novel case of genetically based male breast cancer with dual deleterious gene mutations provides insight into current treatment recommendations and the subtle differences between male breast cancer and female breast cancer. Engaging in discussions surrounding such rare cases not only raises awareness of male breast cancer but also indicates the need for further research aimed at establishing evidence-based management strategies for male patients with breast cancer.

Up-regulation of miR-182 expression after epigenetic modulation of human melanoma cells.

PURPOSE: We sought to investigate the epigenetic regulation of microRNAs (miRNAs) in melanoma. METHODS: We treated two highly metastatic human melanoma cell lines, C8161.9 and WM266-4, with the demethylating agents DAC (5-aza-2'-deoxycytidine) and trichostatin A. Locked nucleic acid-based miRNA expression profiling was utilized to examine the differential expression of miRNAs before and after treatment. RESULTS: We found that miR-182, a miRNA with oncogenic properties, was significantly up-regulated in human melanoma cells after epigenetic modulation. Genome sequence analysis revealed the presence of a prominent CpG island 8-10 kb upstream of mature miR-182. Methylation analysis showed that this genomic region was exclusively methylated in melanoma cells but not in human melanocytes, skin, or peripheral blood mononuclear cells. DISCUSSION: These results indicate that an epigenetic mechanism is likely involved in modulating the expression level of miR-182 in melanoma, and increased expression of oncogenic-like miR-182 could be a concern for melanoma patients after epigenetic therapy.

Impact of Frailty Upon Surgical Decision-Making for Left-Sided Colon Cancer.

Background: Frailty is characterized by reduced physiologic reserve, and for patients with colon cancer, frailty is associated with increased morbidity after resection. One commonly cited reason for performing an end colostomy vs a primary anastomosis in left-sided colon cancer is the belief that frail patients do not have the physiologic reserve to withstand the morbidity associated with an anastomotic leak. We explored the impact of frailty on the type of operation performed in patients with left-sided colon cancer. Methods: We queried the American College of Surgeons National Surgical Quality Improvement Program for patients with colon cancer who underwent a left-sided colectomy from 2016 to 2018. Patients were categorized using the modified 5-item frailty index. Multivariate regression was used to identify independent predictors of complications and type of operation performed. Results: Of 17,461 patients, 20.7% were considered frail. Frail patients received an end colostomy more often than nonfrail patients (11.3% vs 9.6%, P=0.01). On multivariate analysis, frailty was a significant predictor for total medical complications (odds ratio [OR] 1.45, 95% CI 1.29-1.63) and readmission (OR 1.53, 95% CI 1.32-1.77) but was not independently associated with organ space surgical site infections or reoperation. Frailty was independently associated with receiving an end colostomy vs a primary anastomosis (OR 1.23, 95% CI 1.06-1.44), but an end colostomy did not decrease the risk of reoperation or organ space surgical site infections. Conclusion: Frail patients with left-sided colon cancer are more likely to receive an end colostomy, but an end colostomy does not lower the risk of reoperation or organ space surgical site infections. Based on these results, frailty alone should not prompt the decision to perform an end colostomy, but further studies are needed to guide surgical decision-making in this understudied population.

Location, location, location: the BRMS1 protein and melanoma progression.

The metastasis suppressor, BRMS1, has been demonstrated to cause dramatic regression of metastatic lesions without blocking orthotopic tumor growth. The role of BRMS1 is well-documented for several non-melanoma malignancies, such as breast cancer, ovarian cancer and non-small-cell lung cancer. However, its role in melanoma is just beginning to be understood, with a recent article by Slipicevic et al. highlighting the levels of expression of BRMS1 in benign nevi, primary and metastatic melanoma samples. Their findings emphasize that the intracellular location of BRMS1 protein (cytoplasmic or nuclear), appears to have a significant impact upon the metastatic capacity of melanoma cells. Interestingly, this selective localization translates into a statistically significant decrease in the relapse-free period in melanoma patients, further associated with a thicker Breslow's depth of primary melanomas. However, and more importantly, this study begins to define a clearer role for BRMS1 in melanoma that is strictly dependent upon its cellular location, with nuclear expression associated with invasive and metastatic capacity and cytoplasmic expression resulting in repressive effects upon progression and metastasis.

Hospital-Based Same-Day Compared to Overnight-Stay Mastectomy: An American College of Surgeons National Surgical Quality Improvement Program Analysis.

Background: Enhanced Recovery after Surgery for mastectomy has resulted in increased use of outpatient same-day mastectomy (SDM). Whether SDM leads to increased readmissions or reoperations is not well documented. This study examines national data to compare outcomes of SDM to an overnight stay. Methods: We analyzed the American College of Surgeons National Surgical Quality Improvement Program Participant Use Data File from 2016 to 2018 for all mastectomy cases. Cases with a length of stay (LOS) >1 day were excluded. Cases were then categorized into 2 LOS cohorts: SDM vs 1-day LOS. Results: A total of 22,642 cases (80.8% 1-day LOS vs 19.2% SDM) were identified for the final analysis. Patients in the 1-day LOS group were more likely to be older (57.9 vs 54.0 years, P<0.01), be female (98.0% vs 79.8%, P<0.01), and have greater comorbidity (38.1% vs 30.7% American Society of Anesthesiologists classification 3 or 4, P<0.01) compared to the SDM group. Multivariate analysis demonstrated no difference in risk for 30-day wound complications between the SDM and 1-day LOS groups. The risks for 30-day medical complications (1.60 odds ratio [OR], 95% CI 1.06-2.42, P=0.02), reoperations (1.46 OR, 95% CI 1.17-1.81, P<0.01), and readmissions (1.60 OR, 95% CI 1.25-2.05, P<0.01) were higher in the 1-day LOS group. Even after excluding patients undergoing reoperation on the day of surgery, the risk for reoperations (2.3% vs 3.3%, P<0.01) remained higher in the 1-day LOS group. Characteristics associated with 1-day LOS were hypertension, steroid use, diabetes, dyspnea, dependent functional status, bilateral procedures, and breast reconstruction. Conclusion: We demonstrate that SDM is a safe procedure, with no increase in risk for 30-day postoperative complications. Appropriate patients should be offered SDM.

Improving Operating Room Efficiency: Relocating a Surgical Oncology Program Within a Health Care System.

Background: To meet increased community and regional needs for quality services, our hospital system concluded that its established surgical oncology program-consisting of gynecologic oncology (4 physicians), surgical oncology (2 physicians), and otolaryngologic oncology (2 physicians)-would be best served by the transition of the comprehensive surgical oncology program to a new oncology-naive hospital. We describe the overall strategy and approach involved with this move, its implementation, operating room efficiency results, and physician satisfaction associated with the relocation. Methods: The purpose of the systematic plan for relocation, which was developed and refined during the 2 years preceding the move, was to facilitate a collective awareness and understanding of important patient-centered concepts and essential workflow. All parties involved in direct patient cancer care participated in multiple workgroups to successfully transition the surgical oncology practice. Following the transition to the oncology-naive hospital, components of the operative cases and surgical data were prospectively collected for the initial 6 weeks and compared to retrospective data from the last 8 weeks at the established hospital. The surgical day for each surgeon was deconstructed, and measured variables included total surgical cases, total surgical hours, surgical minutes per case, total anesthesia hours, first case on-time surgical starts, surgical stretcher wheels out to surgical stretcher wheels in, surgical stretcher wheels out to next case start, case end to postanesthesia care unit (PACU), and case end to case start. Results: Five hundred twenty-nine surgical cases encompassing 1,076 anesthesia hours and 710 surgical hours were completed during the 14-week evaluation period. The gynecologic oncologists completed the majority of surgical procedures in both settings. The percentage of first case on-time surgical starts initially decreased during the 6-week interval at the oncology-naive hospital, but interval subset analysis suggested a return to the pre-move norm. Surgical stretcher wheels out to surgical stretcher wheels in had a wide range (9 minutes to 305 minutes) for all surgical sections, but no statistically significant difference was seen overall or for any surgical section. Case end to PACU significantly increased for gynecologic oncology but not for surgical oncology or otolaryngologic oncology. Overall case end to case start times decreased nonsignificantly (63.7 ± 3.1 mean minutes vs 60.3 ± 1.7 mean minutes) following the move. A physician survey found that physicians' expectations were met in terms of the move occurring smoothly without major issues, surgical scheduling and accommodation, anesthesia services, and surgical personnel. Physicians indicated less satisfaction with quality and availability of instrumentation. Conclusion: The transfer of established surgical oncology services to an oncology-naive hospital was associated with early surgeon and operating room staff support, as well as process and programmatic alignment among stakeholders. The success of this transition required transparency, open and honest communication, and problem solving at all levels. The move of a surgical oncology program to an oncology-naive hospital was deemed successful without deterioration of time-related variables associated with operating room efficiency and physician satisfaction. The breakdown and analysis of key components of the surgical day offered additional opportunities for quality improvement in operating room efficiency.

MicroRNA-125b confers the resistance of breast cancer cells to paclitaxel through suppression of pro-apoptotic Bcl-2 antagonist killer 1 (Bak1) expression.

Paclitaxel (Taxol) is an effective chemotherapeutic agent for treatment of cancer patients. Despite impressive initial clinical responses, the majority of patients eventually develop some degree of resistance to Taxol-based therapy. The mechanisms underlying cancer cells resistance to Taxol are not fully understood. MicroRNA (miRNA) has emerged to play important roles in tumorigenesis and drug resistance. However, the interaction between the development of Taxol resistance and miRNA has not been previously explored. In this study we utilized a miRNA array to compare the differentially expressed miRNAs in Taxol-resistant and their Taxol-sensitive parental cells. We verified that miR-125b, miR-221, miR-222, and miR-923 were up-regulated in Taxol-resistant cancer cells by real-time PCR. We further investigated the role and mechanisms of miR-125b in Taxol resistance. We found that miR-125b was up-regulated in Taxol-resistant cells, causing a marked inhibition of Taxol-induced cytotoxicity and apoptosis and a subsequent increase in the resistance to Taxol in cancer cells. Moreover, we demonstrated that the pro-apoptotic Bcl-2 antagonist killer 1 (Bak1) is a direct target of miR-125b. Down-regulation of Bak1 suppressed Taxol-induced apoptosis and led to an increased resistance to Taxol. Restoring Bak1 expression by either miR-125b inhibitor or re-expression of Bak1 in miR-125b-overexpressing cells recovered Taxol sensitivity, overcoming miR-125-mediated Taxol resistance. Taken together, our data strongly support a central role for miR-125b in conferring Taxol resistance through the suppression of Bak1 expression. This finding has important implications in the development of targeted therapeutics for overcoming Taxol resistance in a number of different tumor histologies.

A personalized microRNA microarray normalization method using a logistic regression model.

MOTIVATION: MicroRNA (miRNA) is a set of newly discovered non-coding small RNA molecules. Its significant effects have contributed to a number of critical biological events including cell proliferation, apoptosis development, as well as tumorigenesis. High-dimensional genomic discovery platforms (e.g. microarray) have been employed to evaluate the important roles of miRNAs by analyzing their expression profiling. However, because of the small total number of miRNAs and the absence of well-known endogenous controls, the traditional normalization methods for messenger RNA (mRNA) profiling analysis could not offer a suitable solution for miRNA analysis. The need for the establishment of new adaptive methods has come to the forefront. RESULTS: Locked nucleic acid (LNA)-based miRNA array was employed to profile miRNAs using colorectal cancer cell lines under different treatments. The expression pattern of overall miRNA profiling was pre-evaluated by a panel of miRNAs using Taqman-based quantitative real-time polymerase chain reaction (qRT-PCR) miRNA assays. A logistic regression model was built based on qRT-PCR results and then applied to the normalization of miRNA array data. The expression levels of 20 additional miRNAs selected from the normalized list were post-validated. Compared with other popularly used normalization methods, the logistic regression model efficiently calibrates the variance across arrays and improves miRNA microarray discovery accuracy. AVAILABILITY: Datasets and R package are available at http://gauss.usouthal.edu/publ/logit/.

Metastatic Papillary Thyroid Cancer to the Liver: The Central Role of a Multidisciplinary Approach to Treatment.

Background: Differentiated thyroid cancer (DTC) is comprised of papillary and follicular subtypes, and both have an overall excellent long-term prognosis. Patients with localized DTC that is successfully treated, usually with surgery, exhibit long-term survival well above 90%. In contrast, patients who develop distant metastatic disease have a significantly worse overall prognosis and outcome, often with disease that is refractory to conventional therapy such as surgery, radioactive iodine, and hormone suppression. For patients who recur with distant metastatic disease, limited effective treatment options are available, and most die of their disease within 5 years of recurrence. Case Report: We report the case of a 26-year-old female who presented with recurrent papillary thyroid cancer and a metastatic lesion isolated to the liver. Because of the extremely large size of the metastatic liver mass upon initial presentation, we took a neoadjuvant, multifaceted approach to treatment that included selective internal radioembolization therapy, an oral multikinase inhibitor, and surgical resection of the tumor mass after maximal reduction in tumor size. However, the patient died of metastatic DTC after 39 months of treatment. Conclusion: A multimodal, comprehensive approach to managing such complex patients is essential to optimize both the sequence and therapeutic approach to treatment.

Sulindac Modulates the Response of Proficient MMR Colorectal Cancer to Anti-PD-L1 Immunotherapy.

Immune-checkpoint inhibitor (ICI) therapy has been widely used to treat different human cancers, particularly advanced solid tumors. However, clinical studies have reported that ICI immunotherapy benefits only ∼15% of patients with colorectal cancer, specifically those with tumors characterized by microsatellite instability (MSI), a molecular marker of defective DNA mismatch repair (dMMR). For the majority of patients with colorectal cancer who carry proficient MMR (pMMR), ICIs have shown little clinical benefit. In this study, we examined the efficacy of sulindac to enhance the response of pMMR colorectal cancer to anti-PD-L1 immunotherapy. We utilized a CT26 syngeneic mouse tumor model to compare the inhibitory effects of PD-L1 antibody (Ab), sulindac, and their combination on pMMR colorectal cancer tumor growth. We found that mice treated with combination therapy showed a significant reduction in tumor volume, along with increased infiltration of CD8+ T lymphocytes in the tumor tissues. We also demonstrated that sulindac could downregulate PD-L1 by blocking NF-κB signaling, which in turn led to a decrease in exosomal PD-L1. Notably, PD-L1 Ab can be bound and consumed by exosomal PD-L1 in the blood circulation. Therefore, in combination therapy, sulindac downregulating PD-L1 leads to increased availability of PD-L1 Ab, which potentially improves the overall efficacy of anti-PD-L1 therapy. We also show that low-dose sulindac does not appear to have a systemic inhibitory effect on prostaglandin E2 (PGE2). In conclusion, our findings provide unique insights into the mechanism of action and efficacy for sulindac as an immunomodulatory agent in combination with anti-PD-L1 therapy for the treatment of pMMR colorectal cancer.

Cyclin G2, a novel target of sulindac to inhibit cell cycle progression in colorectal cancer.

Sulindac has shown significant clinical benefit in preventing colorectal cancer progression, but its mechanism of action has not been fully elucidated. We have found that sulindac sulfide (SS) is able to inhibit cell cycle progression in human colorectal cancer cells, particularly through G1 arrest. To understand the underlying mechanisms of sulindac inhibitory activity, we have demonstrated that Cyclin G2 up-regulation upon SS treatment can substantially delay cell cycle progression by enhancing the transcriptional activity of FOXO3a in human colorectal tumor cells. MiR-182, an oncogenic microRNA known to inhibit FOXO3a gene expression, is also involved in the suppressive effect of SS on cell cycle progression. This process begins with the down-regulation of miR-182, followed by the enhancement of FOXO3a transcriptional activity and the up-regulation of Cyclin G2. To further determine the clinical utility of this axis, we analyzed the expression of miR-182/FOXO3a/Cyclin G2 in human colorectal tumor samples. Our results show not only that there are significant differences in miR-182/FOXO3a/Cyclin G2 between tumors and normal tissues, but also that the synergetic effect of miR-182 and FOXO3a is associated with predicting tumor progression. Our study demonstrates a novel mechanistic axis consisting of miR-182/FOXO3a/Cyclin G2 that mediates sulindac inhibition of cell cycle progression.

Correction: Evaluation of deacetylase inhibition in metaplastic breast carcinoma using multiple derivations of preclinical models of a new patient-derived tumor.

[This corrects the article DOI: 10.1371/journal.pone.0226464.].

Three-year survival, correlates and salvage therapies in patients receiving first-line pembrolizumab for advanced Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive skin cancer associated with poor survival. Programmed cell death-1 (PD-1) pathway inhibitors have shown high rates of durable tumor regression compared with chemotherapy for MCC. The current study was undertaken to assess baseline and on-treatment factors associated with MCC regression and 3-year survival, and to explore the effects of salvage therapies in patients experiencing initial non-response or tumor progression after response or stable disease following first-line pembrolizumab therapy on Cancer Immunotherapy Trials Network-09/KEYNOTE-017. METHODS: In this multicenter phase II trial, 50 patients with advanced unresectable MCC received pembrolizumab 2 mg/kg every 3 weeks for ≤2 years. Patients were followed for a median of 31.8 months. RESULTS: Overall response rate to pembrolizumab was 58% (complete response 30%+partial response 28%; 95% CI 43.2 to 71.8). Among 29 responders, the median response duration was not reached (NR) at 3 years (range 1.0+ to 51.8+ months). Median progression-free survival (PFS) was 16.8 months (95% CI 4.6 to 43.4) and the 3-year PFS was 39.1%. Median OS was NR; the 3-year OS was 59.4% for all patients and 89.5% for responders. Baseline Eastern Cooperative Oncology Group performance status of 0, greater per cent tumor reduction, completion of 2 years of treatment and low neutrophil-to-lymphocyte ratio were associated with response and longer survival. Among patients with initial disease progression or those who developed progression after response or stable disease, some had extended survival with subsequent treatments including chemotherapies and immunotherapies. CONCLUSIONS: This study represents the longest available follow-up from any first-line anti-programmed death-(ligand) 1 (anti-PD-(L)1) therapy in MCC, confirming durable PFS and OS in a proportion of patients. After initial tumor progression or relapse following response, some patients receiving salvage therapies survived. Improving the management of anti-PD-(L)1-refractory MCC remains a challenge and a high priority. TRIAL REGISTRATION NUMBER: NCT02267603.

Functional characterization of the progestagen-associated endometrial protein gene in human melanoma.

Utilizing gene microarray profiling of melanoma samples, we have recently identified a novel gene overexpressed in both thick primary and metastatic melanomas. This gene, progestagen-associated endometrial protein (PAEP), has never before been implicated in the oncogenic processes of melanoma, with its true function in oncogenesis and tumour progression relatively unknown. Overexpression of the PAEP gene in freshly procured thick primary and metastatic melanoma samples (58%) and daughter cell lines (77%) is confirmed by quantitative RT-PCR, immunohistochemistry, Western blotting and mass spectrometric analysis. We suggest that PAEP gene overexpression is involved with melanoma tumour progression as well as an aggressive phenotype. Transfection of melanoma cells with PAEP small interfering RNA (siRNA) reveals a significant decrease in soft agar colony formation and a marked inhibition of both cell migration and cell invasion. Furthermore, we establish stable melanoma transfectants via PAEP lentiviral small hairpin RNA (shRNA), examine their growth characteristics in a murine xenograft model and reveal that tumour growth is significantly inhibited in two separate melanoma cell lines. Our data strongly implicate the PAEP gene as a tumour growth promoter with oncogenic properties and a potential therapeutic target for patients with advanced melanoma.