MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma.

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

Preventive effect of tertiary lymphoid structures on lymph node metastasis of lung adenocarcinoma.

BACKGROUND: Ectopic lymphoid formations are called tertiary lymphoid structures (TLSs). TLSs in cancer have been reported to be associated with good prognosis and immunotherapy response. However, the relationship between TLSs and lymph node (LN) metastasis is unclear. METHODS: We analyzed 218 patients with radically resected lung adenocarcinoma. TLSs were defined as the overlap of T cell zone and B cell zone. Granzyme B + cells were defined as cytotoxic lymphocytes. We evaluated phenotypes of lymphocytes in TLSs, tumor-infiltrating lymphocytes (TILs) and LNs by immunohistochemistry. We divided the patients into mature TLS (DC-Lamp high) and immature TLS (DC-Lamp low) groups. The relationship between TLS maturation and clinicopathological factors was analyzed. RESULTS: The mature TLS group was associated with significantly lower frequency of LN metastasis (P < 0.0001) and early cancer stage (P = 0.0049). The mature TLS group had significantly more CD8 + (P = 0.0203) and Foxp3 + (P = 0.0141) cells in TILs than the immature TLS group had. Mature TLSs were independently associated with a favorable overall survival (hazard ratio [HR] = 0.17, P = 0.0220) and disease-free survival (HR = 0.54, P = 0.0436). Multivariate analysis showed that mature TLS was an independent low-risk factor for LN metastasis (odds ratio = 0.06, P = 0.0003). The number of cytotoxic lymphocytes in LNs was higher in the mature TLS group than in the immature group (20.0 vs. 15.1, P = 0.017). CONCLUSION: Mature TLSs were associated with an increased number of cytotoxic lymphocytes in draining LNs, a lower frequency of LN metastasis, and favorable outcomes. Mature TLSs may support antitumor immunity by lymphocyte activation.

Transducin Beta-Like 2 is a Potential Driver Gene that Adapts to Endoplasmic Reticulum Stress to Promote Tumor Growth of Lung Adenocarcinoma.

BACKGROUND: Endoplasmic reticulum (ER) stress has a close relation with cancer progression. Blocking the adaptive pathway of ER stress could be an anticancer strategy. Here, we identified an ER stress-related gene, Transducin beta-like 2 (TBL2), an ER-localized type I transmembrane protein, on increased chromosome 7q as a candidate driver gene of lung adenocarcinoma (LUAD). METHODS: The association between TBL2 mRNA expression and prognostic outcomes and clinicopathological factors was analyzed using The Cancer Genome Atlas (TCGA) datasets of LUAD and lung squamous cell carcinoma (LUSC). Localization of TBL2 in tumor tissues was observed by immunohistochemical staining. Gene set enrichment analysis (GSEA) was conducted using TCGA dataset. In vitro cell proliferation assays were performed using TBL2 knockdown LUAD cells, LUSC cells, and LUAD cells overexpressing TBL2. Apoptosis and ATF4 expression (ER stress marker) were evaluated by western blotting. RESULTS: TBL2 was overexpressed in LUAD and LUSC cells. Multivariate analysis indicated high TBL2 mRNA expression was an independent poor prognostic factor of LUAD. GSEA revealed high TBL2 expression was positively correlated to the ER stress response in LUAD. TBL2 knockdown attenuated LUAD cell proliferation under ER stress. TBL2 inhibited apoptosis in LUAD cells under ER stress. TBL2 knockdown reduced ATF4 expression under ER stress. CONCLUSIONS: TBL2 may be a novel driver gene that facilitates cell proliferation, possibly by upregulating ATF4 expression followed by adaptation to ER stress, and it is a poor prognostic biomarker of LUAD.

Survival benefit of using pemetrexed for EGFR mutation-positive advanced non-small-cell lung cancer in a randomized phase III study comparing gefitinib to cisplatin plus docetaxel (WJTOG3405).

BACKGROUND: Pemetrexed is common cytotoxic chemotherapy among non-squamous non-small cell lung cancer (non-Sq-NSCLC) patients; however, among epidermal growth factor receptor (EGFR)-positive lung cancer, there is no clear evidence to support the efficacy of sequential treatment with pemetrexed. MATERIAL AND METHODS: We performed a post-hoc analysis of subsequent chemotherapies among 144 patients who received the post-protocol treatment in the phase III trial WJTOG 3405 comparing gefitinib to cisplatin plus docetaxel, and analyzed the effect of pemetrexed on overall survival (OS). RESULTS: Patients with treatment including pemetrexed exhibited significantly longer OS in comparison to those without pemetrexed; the median OS in the pemetrexed + and pemetrexed- patients were 40.7 months and 28.0 months, respectively (0.55 of HR [95% CI: 0.38-0.80, p = 0.0020]). On the other hand, other treatments, including docetaxel, TS-1 and paclitaxel showed no significant impact on OS. The multivariate analysis with a time-dependent Cox proportional hazards model showed that treatment including pemetrexed, as well as PS 0 and post-operative recurrence, were independent predictors of a good prognosis. Moreover, among patients who received at least four lines of prior treatment, pemetrexed + treatment also significantly prolonged OS in comparison to pemetrexed- treatment (median OS pemetrexed + vs. pemetrexed-: 44.4 months vs. 32.6 months; HR: 0.55 [95% CI: 0.31-0.94, p = 0.0290]). CONCLUSIONS: Sequential treatment including pemetrexed against EGFR-mutated NSCLC might be associated with a better outcome. It was considered that pemetrexed should be administered without fail as a sequential treatment to improve the prognosis of EGFR-mutated NSCLC as well as like EGFR-tyrosine kinase inhibitors.

Identification of SLC38A7 as a Prognostic Marker and Potential Therapeutic Target of Lung Squamous Cell Carcinoma.

BACKGROUND: No effective molecular targeted therapy has been established for SCC. We conducted a comprehensive study of SCC patients using RNA-sequencing and TCGA dataset to clarify the driver oncogene of SCC. METHOD: Forty-six samples of 23 patients were totally analyzed with RNA-sequencing. We then searched for candidate-oncogenes of SCC using the TCGA database. To identify candidate oncogenes, we used the following 2 criteria: (1) the genes of interest were overexpressed in tumor tissues of SCC patients in comparison to normal tissues; and (2) using an integrated mRNA expression and DNA copy number profiling analysis using the TCGA dataset, the DNA copy number of the genes was positively correlated with the mRNA expression. RESULT: We identified 188 candidate-oncogenes. Among those, the high expression of SLC38A7 was a strong prognostic marker that was significantly associated with a poor prognosis in terms of both overall survival (OS) and recurrence-free survival in the TCGA dataset (P < 0.05). Additionally, 202 resected SCC specimens were also subjected to an immunohistochemical analysis. Patients with the high expression of SLC38A7 (alternative name is sodium-coupled amino acid transporters 7) protein showed significantly shorter OS in comparison to those with the low expression of SLC38A7 protein [median OS 3.9 years (95% confidence interval, 2.4-6.4 years) vs 2.2 years (95% confidence interval, 1.9-4.1 years); log rank test: P = 0.0021]. CONCLUSION: SLC38A7, which is the primary lysosomal glutamine transporter required for the extracellular protein-dependent growth of cancer cells, was identified as a candidate therapeutic target of SCC.

Prognostic impact of primary cancer adjoining emphysematous bullae in non-small cell lung cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have become a standard therapy in non-small cell lung cancer (NSCLC). Although lung cancer adjoining emphysematous bullae (Ca-ADJ) were reported to express higher programmed cell death-ligand 1 (PD-L1), the predictive impact of Ca-ADJ on the response to ICIs is unknown. METHODS: Two hundred and fifty-seven advanced or recurrent NSCLC patients treated with ICI monotherapy at Kyushu University Hospital and National Hospital Organization Kyushu Cancer Center were analyzed. To minimize the bias arising from the patients' background, adjusted Kaplan-Meier survival curves and Cox proportional hazards regression analyses using inverse probability of treatment weights (IPTW) were performed. RESULTS: Of the 257 patients, 55 had Ca-ADJ. Patients with Ca-ADJ were significantly associated with younger age (P = 0.0343), male sex (P = 0.0070), and smoking (P = 0.0080). The objective response rate of cases with Ca-ADJ was significantly higher than that of those without Ca-ADJ (36.4% vs. 20.8%, respectively; P = 0.0167). The disease control rate of cases with Ca-ADJ was also significantly higher than tumors without Ca-ADJ (63.6% vs. 47.5%, respectively; P = 0.0341). The IPTW-adjusted Kaplan-Meier curves showed that patients with Ca-ADJ had significantly longer progression-free survival (PFS) and overall survival (OS) than those without Ca-ADJ (P = 0.0407 and P = 0.0126, respectively). On IPTW-adjusted Cox analysis, Ca-ADJ was an independent predictor of PFS and OS (P < 0.0001 and P < 0.0001, respectively). CONCLUSIONS: Patients with Ca-ADJ may be good candidates for ICIs. These findings should be validated prospectively.

Identification of the Best Prognostic Marker Among Immunonutritional Parameters Using Serum C-Reactive Protein and Albumin in Non-Small Cell Lung Cancer.

BACKGROUND: Three immune-nutritional parameters exist for malignant tumors using serum C-reactive protein (CRP) and albumin: the Glasgow prognostic score (GPS), the modified GPS (mGPS), and the CRP-albumin ratio (CAR). However, it remains unclear which of the three parameters is the most predictive of prognosis. Therefore, this study compared the clinical and prognostic significance of these parameters for non-small cell carcinoma (NSCLC). METHODS: The study retrospectively enrolled 596 NSCLC patients who underwent surgical resection at the authors' institution from January 2010 to December 2015 and investigated the clinicopathologic significance of GPS, mGPS, and CAR. The optimal cutoff value for CAR was determined by a receiver operating curve (ROC). RESULTS: The median age of the patients was 69 years. Lymph node metastases were identified in 99 patients, and 455 patients had a diagnosis of stage 1 disease. The positivity for GPS was 7.6%, and that of mGPS (score, 1 or 2) was 12.2%. Of the 596 patients, 480 patients (80.5%) were classified in the high CAR group. In univariate survival analyses, all three parameters were associated significantly with postoperative survival. The multivariate analyses showed CAR to be an independent prognostic factor. Additionally, survival analyses of the stage 1 subgroup were performed because CAR was higher for patients with an advanced stage of disease or lymph node metastases. In these subgroup analyses, CAR also was an independent prognostic factor. CONCLUSION: As the most prognostic index, CAR may be useful among the immunonutritional parameters using CRP and albumin for resected NSCLC.

Prognostic Impact of Smoking Period in Patients with Surgically Resected Non-small Cell Lung Cancer.

BACKGROUND: The pack-year index, which is calculated by multiplying a smoking period by the number of cigarette packs smoked per day, is frequently used to investigate the risk of developing lung cancer. Notably, however, whether the smoking period or the number of packs per day is more predictive of postoperative prognosis remains unclear in non-small cell lung cancer (NSCLC) patients who receive curative lung resection. PATIENTS AND METHODS: Initial screening included 2055 consecutive lung cancer patients who had underwent curative lung resection between 2000 and 2016 at a single center in Japan. Data from 1134 NSCLC patients with smoking history were ultimately analyzed. Time-dependent areas under the curve (AUCs) were used to compare diagnostic accuracy. RESULTS: On univariate analysis, the number of packs smoked per day was not a significant predictor of disease-free survival (DFS; p = 0.2387) or overall survival (OS; p = 0.1357). On multivariable analysis, smoking period was an independent predictor of DFS and OS (both p < 0.0001). Time-dependent smoking period AUCs were superior to those of number of packs smoked per day. On subgroup analyses, patients with a smoking period ≥ 40 years had significantly shorter DFS and OS than those with a smoking period of < 40 years, independent of sex, clinical stage, and histological type. CONCLUSIONS: Smoking period was a significant prognostic indicator in NSCLC patients who underwent curative lung resection, which should be validated in further prospective and/or multicenter studies with large sample sizes.

Predictive and prognostic impact of primary tumor-bearing lobe in nonsmall cell lung cancer patients treated with anti-PD-1 therapy.

Immunotherapy targeting programmed cell death-1 (PD-1) has become a standard pharmacological therapy. Although tumor mutation burden level was reported to depend on the tumor location in nonsmall cell lung cancer (NSCLC), predictive impact of the tumor location on the response to anti-PD-1 therapy is unknown. Two hundred and seventeen advanced or recurrent NSCLC patients treated with anti-PD-1 therapy at Kyushu University Hospital and National Hospital Organization Kyushu Cancer Center were analyzed. To minimize the bias arising from the patients' background, adjusted Kaplan-Meier survival curves and Cox proportional hazards regression analyses using inverse probability of treatment weights (IPTW) were performed. Of the 217 patients, 132, 27, and 58 had primary NSCLC in upper, middle, and lower lobes, respectively. Patients with NSCLC in upper lobe were significantly associated with younger age (P = .0070) and smoker (P = .0003). The epidermal growth factor receptor-wild type and tumor location in upper lobe were independent predictors of disease control (P = .0175 and P = .0425, respectively). The IPTW-adjusted Kaplan-Meier curves showed that patients with NSCLC in the upper lobes had significantly longer progression-free survival (PFS) and overall survival (OS) than those in middle/lower lobes (P = .0026 and P = .0015, respectively). On IPTW adjusted Cox analysis, NSCLC in the upper lobe was an independent predictor of PFS and OS (P = .0078 and P = .0034, respectively). Patients with primary NSCLC in the upper lobes may be good candidates for anti-PD-1 therapy. These findings should be validated prospectively.

Surgical Repair of Pleuroperitoneal Communication with Continuous Ambulatory Peritoneal Dialysis.

BACKGROUND: Pleuroperitoneal communication is a serious complication in patients receiving continuous ambulatory peritoneal dialysis. However, few single-institutional reports discuss the details of pleuroperitoneal communication in continuous ambulatory peritoneal dialysis patients regarding the intraoperative findings, postoperative course, and outcomes. METHODS: We retrospectively reviewed the records of consecutive pleuroperitoneal communication patients who were treated surgically from September 2008 to March 2016. RESULTS: All four patients had right-sided hydrothorax. The time from introduction of continuous ambulatory peritoneal dialysis to the diagnosis of hydrothorax ranged from 1 to 12 months (average: 5.5 months). Case 1 and case 4 had bleblike lesions near the center of the diaphragm; case 2 had a small hole located near the cardiophrenic angle, and case 3 had thinning of the diaphragm near the cardiophrenic angle. All lesions except for case 3 were directly closed with absorbable suture and reinforced by fibrin glue and a polyglycolic acid sheet. In case 3, the thinned diaphragm was reinforced using fibrin glue, a sealing sheet, and pericardial fat pad tissue. Continuous ambulatory peritoneal dialysis was reinitiated an average period of 11 days (range: 4-15 days) postoperatively. During postoperative follow-up, there was no recurrence of hydrothorax. Continuous ambulatory peritoneal dialysis was continued for an average of 16.7 months (range: 3-34 months) after surgical treatment. CONCLUSIONS: Surgical treatment for pleuroperitoneal communication is a safe and acceptable procedure and could greatly benefit continuous ambulatory peritoneal dialysis patients.

The C-Reactive Protein/Albumin Ratio is a Novel Significant Prognostic Factor in Patients with Malignant Pleural Mesothelioma: A Retrospective Multi-institutional Study.

BACKGROUND: Malignant pleural mesothelioma (MPM), a devastating neoplasm, is traditionally considered to be resistant to antitumor therapy. Identification of clinical prognostic indicators is therefore needed. Although the C-reactive protein/albumin ratio (CAR) has been used to predict the prognosis of many types of malignancy, its utility in patients with MPM is unknown. METHODS: The data of 100 patients diagnosed as having MPM from 1995 to 2015 at the National Kyushu Cancer Center and Kyushu University were analyzed. The CAR was calculated as serum C-reactive protein concentration divided by albumin concentration. A cutoff for CAR was set at 0.58 according to a receiver operating characteristics curve for 1-year survival. RESULTS: Thirty-five of the 100 (35.0%) patients were classified as having a high CAR. A high CAR was significantly associated with advanced clinical stage (p < 0.001) and chemotherapy alone (p = 0.002). Patients with a high CAR had significantly shorter overall survival (OS) (p < 0.001) and disease- or progression-free survival (DFS/PFS) (p < 0.001). These associations between CAR and prognosis remained significant after propensity score-matching. In multivariate analysis, a high CAR was an independent predictor of shorter OS and DFS/PFS (p = 0.003 and p = 0.008, respectively). Multivariate analyses of the subgroups of patients who had received chemotherapy and of patients who had undergone surgery also showed that a high CAR was an independent predictor of shorter OS and DFS/PFS. CONCLUSIONS: CAR is an independent predictor of prognosis in MPM patients. This prognostic index contributes to clinicians' ability to predict benefit from treatment. Further larger, prospective studies are necessary to validate these findings.

Clinical Impact and Risk Factors for Skeletal Muscle Loss After Complete Resection of Early Non-small Cell Lung Cancer.

BACKGROUND: A relationship between sarcopenia diagnosed by skeletal muscle area (SMA) and poor prognosis in cancer patients has recently been reported. This study aimed to clarify the clinical significance of postoperatively decreased SMA in patients with early non-small cell lung cancer (NSCLC). METHODS: This study selected 101 patients with pathologic stage 1 NSCLC who had undergone pre- and postoperative (~ 1 year) computed tomography scans and lobectomy between 2005 and 2010 at Kyushu University Hospital. The post/pre ratio was defined as the postoperative normalized SMA (cm2/m2) at the 12th thoracic vertebra level divided by the preoperative normalized SMA. The cutoff value for the post/pre ratio was set at 0.9. RESULTS: The study classified 31 patients (30.7%) as having decreased SMA. Poor performance status (PS) was significantly associated with decreased SMA (p = 0.048). The patients with decreased SMA had a significantly shorter disease-free survival (DFS) (p < 0.001) and overall survival (OS) (p < 0.001) than the other patients. Decreased SMA was found to be an independent prognostic factor for DFS (p = 0.010) and OS (p = 0.0072). The independent risk factors for skeletal muscle loss included poor PS (PS ≥ 1) and obstructive ventilatory impairment [forced expiratory volume (FEV) 1% < 70%]. CONCLUSIONS: Skeletal muscle loss after surgery is significantly associated with postoperative poor outcomes for patients with early NSCLC. Patients with poor PS, obstructive ventilatory impairment, or both need careful support to maintain their skeletal muscle mass. Future prospective studies may clarify whether physical activity and nutritional support improve postoperative prognosis.

Diaphragmatic hernia caused by heterotopic endometriosis in Chilaiditi syndrome: report of a case.

A 50-year-old Japanese female was admitted to our hospital because of ileus due to Chilaiditi syndrome. Her symptoms did not improve with conservative therapy, so chest and abdominal computed tomography (CT) was performed on the fifth day after hospital admission. A diagnosis of incarceration of a right diaphragmatic hernia was established in the coronal view of CT, and emergency surgery was performed. A dilated loop of small intestine was seen in the right thoracic cavity, which was strangulated by the 2-cm defect in the diaphragm. Primary closure of the diaphragm was performed. Approximately 80 cm of the terminal ileum showed obvious ischemic changes, and it was cut and reconstructed. Postoperatively, the patient made an uneventful recovery and was discharged on the 15th postoperative day. A histological examination of the specimen of the diaphragm around the hernia orifice showed the presence of a small cystiform glandular system with hemorrhage and congestion. These findings indicated that heterotopic endometriosis was present in the diaphragm. This report describes the first known case of right diaphragmatic hernia secondary to heterotopic endometriosis in a patient with Chilaiditi syndrome. The clinical course and management of affected patients and a literature review of these three unusual conditions are discussed.

XIST and MUC1-C form an auto-regulatory pathway in driving cancer progression.

The long non-coding RNA X-inactive specific transcript (lncRNA XIST) and MUC1 gene are dysregulated in chronic inflammation and cancer; however, there is no known interaction of their functions. The present studies demonstrate that MUC1-C regulates XIST lncRNA levels by suppressing the RBM15/B, WTAP and METTL3/14 components of the m6A methylation complex that associate with XIST A repeats. MUC1-C also suppresses the YTHDF2-CNOT1 deadenylase complex that recognizes m6A sites and contributes to XIST decay with increases in XIST stability and expression. In support of an auto-regulatory pathway, we show that XIST regulates MUC1-C expression by promoting NF-κB-mediated activation of the MUC1 gene. Of significance, MUC1-C and XIST regulate common genes associated with inflammation and stemness, including (i) miR-21 which is upregulated across pan-cancers, and (ii) TDP-43 which associates with the XIST E repeats. Our results further demonstrate that the MUC1-C/XIST pathway (i) is regulated by TDP-43, (ii) drives stemness-associated genes, and (iii) is necessary for self-renewal capacity. These findings indicate that the MUC1-C/XIST auto-regulatory axis is of importance in cancer progression.

MUC1-C is a target of salinomycin in inducing ferroptosis of cancer stem cells.

The oncogenic MUC1-C transmembrane protein is a critical effector of the cancer stem cell (CSC) state. Addiction to MUC1-C for self-renewal in the progression of human cancers has emphasized the need for development of anti-MUC1-C agents. However, there are presently no approved small molecules for targeting MUC1-C-dependent CSCs. In screening for small molecules, we identified salinomycin (SAL), an inducer of ferroptosis, as a potent inhibitor of MUC1-C signaling. We demonstrate that SAL suppresses MUC1-C expression by disrupting a NF-κB/MUC1-C auto-inductive circuit that is necessary for ferroptosis resistance. Our results show that SAL-induced MUC1-C suppression downregulates a MUC1-C→MYC pathway that activates genes encoding (i) glutathione-disulfide reductase (GSR), and (ii) the LDL receptor related protein 8 (LRP8), which inhibit ferroptosis by generating GSH and regulating selenium levels, respectively. GSR and LRP8 contribute to the function of glutathione peroxidase 4 (GPX4), an essential negative regulator of ferroptotic cell death. We demonstrate that targeting MUC1-C genetically or with the GO-203 peptide inhibitor suppresses GPX4 expression and GPX activity in association with the induction of ferroptosis. Studies of CSCs enriched by serial passage as tumorspheres further demonstrate that the effects of SAL are mediated by downregulation of MUC1-C and thereby overcoming resistance to ferroptosis. As confirmation of these results, rescue of MUC1-C downregulation with the MUC1-C cytoplasmic domain (i) reversed the suppression of GSR, LRP8 and GPX4 expression, and (ii) attenuated the induction of ferroptosis. These findings identify SAL as a unique small molecule inhibitor of MUC1-C signaling and demonstrate that MUC1-C is an important effector of resistance to ferroptosis.

MUC1-C Is a Common Driver of Acquired Osimertinib Resistance in NSCLC.

INTRODUCTION: Osimertinib is an irreversible EGFR tyrosine kinase inhibitor approved for the first-line treatment of patients with metastatic NSCLC harboring EGFR exon 19 deletions or L858R mutations. Patients treated with osimertinib invariably develop acquired resistance by mechanisms involving additional EGFR mutations, MET amplification, and other pathways. There is no known involvement of the oncogenic MUC1-C protein in acquired osimertinib resistance. METHODS: H1975/EGFR (L858R/T790M) and patient-derived NSCLC cells with acquired osimertinib resistance were investigated for MUC1-C dependence in studies of EGFR pathway activation, clonogenicity, and self-renewal capacity. RESULTS: We reveal that MUC1-C is up-regulated in H1975 osimertinib drug-tolerant persister cells and is necessary for activation of the EGFR pathway. H1975 cells selected for stable osimertinib resistance (H1975-OR) and MGH700-2D cells isolated from a patient with acquired osimertinib resistance are found to be dependent on MUC1-C for induction of (1) phospho (p)-EGFR, p-ERK, and p-AKT, (2) EMT, and (3) the resistant phenotype. We report that MUC1-C is also required for p-EGFR, p-ERK, and p-AKT activation and self-renewal capacity in acquired osimertinib-resistant (1) MET-amplified MGH170-1D #2 cells and (2) MGH121 Res#2/EGFR (T790M/C797S) cells. Importantly, targeting MUC1-C in these diverse models reverses osimertinib resistance. In support of these results, high MUC1 mRNA and MUC1-C protein expression is associated with a poor prognosis for patients with EGFR-mutant NSCLCs. CONCLUSIONS: Our findings reveal that MUC1-C is a common effector of osimertinib resistance and is a potential target for the treatment of osimertinib-resistant NSCLCs.

MUC1-C regulates NEAT1 lncRNA expression and paraspeckle formation in cancer progression.

The MUC1 gene evolved in mammals for adaptation of barrier tissues in response to infections and damage. Paraspeckles are nuclear bodies formed on the NEAT1 lncRNA in response to loss of homeostasis. There is no known intersection of MUC1 with NEAT1 or paraspeckles. Here, we demonstrate that the MUC1-C subunit plays an essential role in regulating NEAT1 expression. MUC1-C activates the NEAT1 gene with induction of the NEAT1_1 and NEAT1_2 isoforms by NF-κB- and MYC-mediated mechanisms. MUC1-C/MYC signaling also induces expression of the SFPQ, NONO and FUS RNA binding proteins (RBPs) that associate with NEAT1_2 and are necessary for paraspeckle formation. MUC1-C integrates activation of NEAT1 and RBP-encoding genes by recruiting the PBAF chromatin remodeling complex and increasing chromatin accessibility of their respective regulatory regions. We further demonstrate that MUC1-C and NEAT1 form an auto-inductive pathway that drives common sets of genes conferring responses to inflammation and loss of homeostasis. Of functional significance, we find that the MUC1-C/NEAT1 pathway is of importance for the cancer stem cell (CSC) state and anti-cancer drug resistance. These findings identify a previously unrecognized role for MUC1-C in the regulation of NEAT1, RBPs, and paraspeckles that has been co-opted in promoting cancer progression.

MUC1-C Dependence for the Progression of Pancreatic Neuroendocrine Tumors Identifies a Druggable Target for the Treatment of This Rare Cancer.

Patients with pancreatic neuroendocrine tumors (pNETs) have limited access to effective targeted agents and invariably succumb to progressive disease. MUC1-C is a druggable oncogenic protein linked to driving pan-cancers. There is no known involvement of MUC1-C in pNET progression. The present work was performed to determine if MUC1-C represents a potential target for advancing pNET treatment. We demonstrate that the MUC1 gene is upregulated in primary pNETs that progress with metastatic disease. In pNET cells, MUC1-C drives E2F- and MYC-signaling pathways necessary for survival. Targeting MUC1-C genetically and pharmacologically also inhibits self-renewal capacity and tumorigenicity. Studies of primary pNET tissues further demonstrate that MUC1-C expression is associated with (i) an advanced NET grade and pathological stage, (ii) metastatic disease, and (iii) decreased disease-free survival. These findings demonstrate that MUC1-C is necessary for pNET progression and is a novel target for treating these rare cancers with anti-MUC1-C agents under clinical development.

Identification of MUC1-C as a Target for Suppressing Progression of Head and Neck Squamous Cell Carcinomas.

The MUC1-C protein is aberrantly expressed in adenocarcinomas of epithelial barrier tissues and contributes to their progression. Less is known about involvement of MUC1-C in the pathogenesis of squamous cell carcinomas (SCC). Here, we report that the MUC1 gene is upregulated in advanced head and neck SCCs (HNSCC). Studies of HNSCC cell lines demonstrate that the MUC1-C subunit regulates expression of (i) RIG-I and MDA5 pattern recognition receptors, (ii) STAT1 and IFN regulatory factors, and (iii) downstream IFN-stimulated genes. MUC1-C integrates chronic activation of the STAT1 inflammatory pathway with induction of the ∆Np63 and SOX2 genes that are aberrantly expressed in HNSCCs. In extending those dependencies, we demonstrate that MUC1-C is necessary for NOTCH3 expression, self-renewal capacity, and tumorigenicity. The findings that MUC1 associates with ∆Np63, SOX2 and NOTCH3 expression by single-cell RNA sequencing analysis further indicate that MUC1-C drives the HNSCC stem cell state and is a target for suppressing HNSCC progression. SIGNIFICANCE: This work reports a previously unrecognized role for MUC1-C in driving STAT1-mediated chronic inflammation with the progression of HNSCC and identifies MUC1-C as a druggable target for advanced HNSCC treatment.