Targeting Hypoxia Sensitizes TNBC to Cisplatin and Promotes Inhibition of Both Bulk and Cancer Stem Cells.

Development of targeted therapies for triple-negative breast cancer (TNBC) is an unmet medical need. Cisplatin has demonstrated its promising potential for the treatment of TNBC in clinical trials; however, cisplatin treatment is associated with hypoxia that, in turn, promotes cancer stem cell (CSC) enrichment and drug resistance. Therapeutic approaches to attenuate this may lead to increased cisplatin efficacy in the clinic for the treatment of TNBC. In this report we analyzed clinical datasets of TNBC and found that TNBC patients possessed higher levels of EGFR and hypoxia gene expression. A similar expression pattern was also observed in cisplatin-resistant ovarian cancer cells. We, thus, developed a new therapeutic approach to inhibit EGFR and hypoxia by combination treatment with metformin and gefitinib that sensitized TNBC cells to cisplatin and led to the inhibition of both CD44+/CD24- and ALDH+ CSCs. We demonstrated a similar inhibition efficacy on organotypic cultures of TNBC patient samples ex vivo. Since these drugs have already been used frequently in the clinic; this study illustrates a novel, clinically translatable therapeutic approach to treat patients with TNBC.

C-reactive Protein in HPV-Positive and HPV-Negative Oropharyngeal Cancer.

OBJECTIVE: Evaluate serum C-reactive protein (CRP) in human papillomavirus (HPV)-positive oropharynx cancer as compared with HPV-negative oropharynx cancer and determine if CRP levels were associated with overall survival and/or recurrence-free survival. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary care academic cancer center between 2007 and 2010. SUBJECTS AND METHODS: Among patients with oropharynx cancer and confirmed HPV status, plasma CRP levels were measured with a high-sensitivity ELISA kit. Multivariable logistic regression analysis compared 4 categories of CRP (low, moderate, high, very high) between the HPV-positive and HPV-negative groups. Kaplan-Meier methods and Cox regression models were used to determine overall survival and recurrence-free survival by CRP level in both populations. RESULTS: Between 113 HPV-positive and 110 HPV-negative patients, CRP levels were significantly higher in the HPV-positive group, but these levels did not demonstrate a statistically significant dose-response trend. Higher CRP levels were also associated with reduced overall survival ( P = .016) and recurrence-free survival ( P < .001) within the HPV-negative group in univariable analysis; in multivariate analysis, the comparisons were not significantly different. Within HPV-positive oropharynx cancer, CRP levels were not significantly associated with overall survival or recurrence-free survival in univariable or multivariable analyses. CONCLUSION: Circulating CRP was higher in HPV-positive versus HPV-negative oropharynx cancer. Among HPV-negative patients, higher CRP levels were associated with reduced survival.

Rationally Designed 3D Hydrogels Model Invasive Lung Diseases Enabling High-Content Drug Screening.

Cell behavior is highly dependent upon microenvironment. Thus, to identify drugs targeting metastatic cancer, screens need to be performed in tissue mimetic substrates that allow cell invasion and matrix remodeling. A novel biomimetic 3D hydrogel platform that enables quantitative analysis of cell invasion and viability at the individual cell level is developed using automated data acquisition methods with an invasive lung disease (lymphangioleiomyomatosis, LAM) characterized by hyperactive mammalian target of rapamycin complex 1 (mTORC1) signaling as a model. To test the lung-mimetic hydrogel platform, a kinase inhibitor screen is performed using tuberous sclerosis complex 2 (TSC2) hypomorphic cells, identifying Cdk2 inhibition as a putative LAM therapeutic. The 3D hydrogels mimic the native niche, enable multiple modes of invasion, and delineate phenotypic differences between healthy and diseased cells, all of which are critical to effective drug screens of highly invasive diseases including lung cancer.

Does metformin usage improve survival in head and neck squamous cell carcinoma? A population-based study.

BACKGROUND: We sought to expand upon preliminary data suggesting that metformin confers a survival benefit to patients with head and neck squamous cell carcinoma (HNSCC). METHODS: A large-scale retrospective cohort study of all patients in Ontario diagnosed with squamous cancer of the larynx, hypopharynx, and nasopharynx between Dec 1st 2007 to Dec 1st 2012 was undertaken. The Institute for Clinical and Evaluative Sciences was accessed to obtain patient demographic, treatment and outcome information. We included patients on metformin at the time of diagnosis. Kaplan Meier methods and Cox Regression models were used. RESULTS: Patients taking metformin at the time of diagnosis had a higher comorbid status but were otherwise similar to patients without metformin usage. Using multivariate analysis, neither overall survival nor disease specific survival was improved in patients on metformin (OS: HR 1.123, p = .338; DSS: HR 1.048, p = .792). CONCLUSIONS: No survival advantage was observed in patients with HNSCC taking metformin at the time of diagnosis.

Correction to: HPV DNA in saliva from patients with SCC of the head and neck is specific for p16-positive oropharyngeal tumours.

Following publication of the original article [1], the authors reported an error in one of the author names. In this Correction the incorrect and correct author names are listed.

Co-inhibition of mTORC1, HDAC and ESR1α retards the growth of triple-negative breast cancer and suppresses cancer stem cells.

Triple-negative breast cancer (TNBC) is the most refractory subtype of breast cancer. It causes the majority of breast cancer-related deaths, which has been largely associated with the plasticity of tumor cells and persistence of cancer stem cells (CSCs). Conventional chemotherapeutics enrich CSCs and lead to drug resistance and disease relapse. Development of a strategy capable of inhibiting both bulk and CSC populations is an unmet medical need. Inhibitors against estrogen receptor 1, HDACs, or mTOR have been studied in the treatment of TNBC; however, the results are inconsistent. In this work, we found that patient TNBC samples expressed high levels of mTORC1 and HDAC genes in comparison to luminal breast cancer samples. Furthermore, co-inhibition of mTORC1 and HDAC with rapamycin and valproic acid, but neither alone, reproducibly promoted ESR1 expression in TNBC cells. In combination with tamoxifen (inhibiting ESR1), both S6RP phosphorylation and rapamycin-induced 4E-BP1 upregulation in TNBC bulk cells was inhibited. We further showed that fractionated CSCs expressed higher levels of mTORC1 and HDAC than non-CSCs. As a result, co-inhibition of mTORC1, HDAC, and ESR1 was capable of reducing both bulk and CSC subpopulations as well as the conversion of fractionated non-CSC to CSCs in TNBC cells. These observations were partially recapitulated with the cultured tumor fragments from TNBC patients. Furthermore, co-administration of rapamycin, valproic acid, and tamoxifen retarded tumor growth and reduced CD44high/+/CD24low/- CSCs in a human TNBC xenograft model and hampered tumorigenesis after secondary transplantation. Since the drugs tested are commonly used in clinic, this study provides a new therapeutic strategy and a strong rationale for clinical evaluation of these combinations for the treatment of patients with TNBC.

Activating Transcription Factor 3 as a Novel Regulator of Chemotherapy Response in Breast Cancer.

Anthracyclines, such as doxorubicin, are used as first-line chemotherapeutics, usually in combination therapies, for the treatment of advanced breast cancer. While these drugs have been successful therapeutic options, their use is limited due to serious drug related toxicities and acquired tumor resistance. Uncovering the molecular mechanisms that mediate doxorubicin's cytotoxic effect will lead to the identification of novel more efficacious combination therapies and allow for reduced doses of doxorubicin to be administered while maintaining efficacy. In our study, we demonstrate that activating transcription factor (ATF) 3 expression was upregulated by doxorubicin treatment in a representative panel of human breast cancer cell lines MCF7 and MDA-MB-231. We have also shown that doxorubicin treatment can induce ATF3 expression in ex vivo human breast and ovarian tumor samples. The upregulation of ATF3 in the cell lines was regulated by multiple cellular mechanisms including the activation of JNK and ATM signaling pathways. Importantly, loss of ATF3 expression resulted in reduced sensitivity to doxorubicin treatment in mouse embryonic fibroblasts. Through a 1200 FDA-approved compound library screen, we identified a number of agents whose cytotoxicity is dependent on ATF3 expression that also enhanced doxorubicin induced cytotoxicity. For example, the combination of the HDAC inhibitor vorinostat or the nucleoside analogue trifluridine could synergistically enhance doxorubicin cytotoxicity in the MCF7 cell line. Synergy in cell lines with the combination of ATF3 inducers and patients with elevated basal levels of ATF3 shows enhanced response to chemotherapy. Taken together, our results demonstrate a role for ATF3 in mediating doxorubicin cytotoxicity and provide rationale for the combination of ATF3-inducing agents with doxorubicin as a novel therapeutic approach.

Effect of statin use on oncologic outcomes in head and neck squamous cell carcinoma.

BACKGROUND: Preclinical and early-phase clinical studies have suggested an oncoprotective role of statins in head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to determine whether incidental statin use in patients with human papillomavirus (HPV)-negative HNSCC is predictive of improved oncologic outcomes. METHODS: A retrospective cohort study of 1194 patients from the Ontario Cancer Registry diagnosed with HNSCC from 2007 to 2012 was performed using linked databases from the Institute for Clinical Evaluative Sciences. Overall survival (OS) and disease-specific survival (DSS) were compared between patients taking statins and controls. RESULTS: Patients with statin exposure demonstrated improved OS (hazard ratio [HR] 0.758; P = .0011; 95% confidence interval [CI] 0.642-0.896), and DSS (HR 0.693; P = .0040; 95% CI 0.539-0.889) compared with those not on statins at the time of diagnosis. CONCLUSION: Incidental statin use at the time of diagnosis of HPV-negative squamous cell carcinoma (SCC) of the larynx, hypopharynx, and nasopharynx demonstrated improved OS and DSS.

Human papillomavirus: An unlikely etiologic factor in sinonasal inverted papilloma.

OBJECTIVES/HYPOTHESIS: Tenuous evidence has supported the hypothesis that sinonasal inverted papilloma (SNIP) arise from human papillomavirus (HPV) infection. To clarify the role of HPV in SNIP, all known HPV sub-types were evaluated by employing a robust polymerase chain reaction-based method in a wide variety of SNIPs from a single institution. STUDY DESIGN: Retrospective surgical specimen tumor sample analysis. METHODS: HPV positivity among SNIP samples and those with squamous cell carcinoma (SCC) were compared. Immunohistochemistry was used to quantify p16 (over)expression among tumors as a surrogate marker for HPV. RESULTS: HPV was detected in 10/76 (13%) SNIP specimens. Identified HPV subtypes included nononcogenic 6 and 11 (6/76, 8%) and oncogenic 16, 18, 45, 56 (4/76, 5%). There was no HPV positivity among SCC samples. Only 4/10 (40%) HPV + samples had > 75% p16 cell staining. CONCLUSION: HPV is not supported as an etiological driver of SNIP development or progression to SCC. The p16 biomarker is not a sensitive indicator of HPV positivity in SNIP. LEVEL OF EVIDENCE: NA Laryngoscope, 2443-2447, 2018.

Dual inhibition of Wnt and Yes-associated protein signaling retards the growth of triple-negative breast cancer in both mesenchymal and epithelial states.

Triple-negative breast cancer (TNBC), the most refractory subtype of breast cancer to current treatments, accounts disproportionately for the majority of breast cancer-related deaths. This is largely due to cancer plasticity and the development of cancer stem cells (CSCs). Recently, distinct yet interconvertible mesenchymal-like and epithelial-like states have been revealed in breast CSCs. Thus, strategies capable of simultaneously inhibiting bulk and CSC populations in both mesenchymal and epithelial states have yet to be developed. Wnt/ß-catenin and Hippo/YAP pathways are crucial in tumorigenesis, but importantly also possess tumor suppressor functions in certain contexts. One possibility is that TNBC cells in epithelial or mesenchymal state may differently affect Wnt/ß-catenin and Hippo/YAP signaling and CSC phenotypes. In this report, we found that YAP signaling and CD44high /CD24-/low CSCs were upregulated while Wnt/ß-catenin signaling and ALDH+ CSCs were downregulated in mesenchymal-like TNBC cells, and vice versa in their epithelial-like counterparts. Dual knockdown of YAP and Wnt/ß-catenin, but neither alone, was required for effective suppression of both CD44high /CD24-/low and ALDH+ CSC populations in mesenchymal and epithelial TNBC cells. These observations were confirmed with cultured tumor fragments prepared from patients with TNBC after treatment with Wnt inhibitor ICG-001 and YAP inhibitor simvastatin. In addition, a clinical database showed that decreased gene expression of Wnt and YAP was positively correlated with decreased ALDH and CD44 expression in patients' samples while increased patient survival. Furthermore, tumor growth of TNBC cells in either epithelial or mesenchymal state was retarded, and both CD44high /CD24-/low and ALDH+ CSC subpopulations were diminished in a human xenograft model after dual administration of ICG-001 and simvastatin. Tumorigenicity was also hampered after secondary transplantation. These data suggest a new therapeutic strategy for TNBC via dual Wnt and YAP inhibition.

Customized Viral Immunotherapy for HPV-Associated Cancer.

The viral-transforming proteins E6 and E7 make human papillomavirus-positive (HPV+) malignancies an attractive target for cancer immunotherapy. However, therapeutic vaccination exerts limited efficacy in the setting of advanced disease. We designed a strategy to induce substantial specific immune responses against multiple epitopes of E6 and E7 proteins based on an attenuated transgene from HPV serotypes 16 and 18 that is incorporated into MG1-Maraba virotherapy (MG1-E6E7). Mutations introduced to the transgene abrogate the ability of E6 and E7 to perturb p53 and retinoblastoma, respectively, while maintaining the ability to invoke tumor-specific, multifunctional CD8+ T-cell responses. Boosting with MG1-E6E7 significantly increased the magnitude of T-cell responses compared with mice treated with a priming vaccine alone (greater than 50 × 106 E7-specific CD8+ T cells per mouse was observed, representing a 39-fold mean increase in boosted animals). MG1-E6E7 vaccination in the HPV+ murine model TC1 clears large tumors in a CD8+-dependent manner and results in durable immunologic memory. MG1-Maraba can acutely alter the tumor microenvironment in vivo and exploit molecular hallmarks of HPV+ cancer, as demonstrated by marked infection of HPV+ patient tumor biopsies and is, therefore, ideally suited as an oncolytic treatment against clinical HPV+ cancer. This approach has the potential to be directly translatable to human clinical oncology to tackle a variety of HPV-associated neoplasms that cause significant morbidity and mortality globally. Cancer Immunol Res; 5(10); 847-59. ©2017 AACR.

Vulvar Squamous Cell Carcinoma (VSCC) as Two Diseases: HPV Status Identifies Distinct Mutational Profiles Including Oncogenic Fibroblast Growth Factor Receptor 3.

Purpose: Patients with advanced or recurrent invasive vulvar squamous cell carcinoma (VSCC) have limited treatment options and a grave prognosis. Understanding the genomic landscape may facilitate the identification of new therapies and improve clinical outcomes.Experimental Design: A retrospective chart review and molecular analysis of patients with VSCC from 2000 to 2016 was performed at the Ottawa Hospital Research Institute. The presence of oncogenic human papillomavirus (HPV) was determined by nested PCR and amplified DNA was sequenced using the Ion AmpliSeq Cancer Hotspot v2 Panel. The patients were divided into two groups according to HPV status (HPV-positive versus HPV-negative) and clinical outcome correlated with mutation status using descriptive statistics.Results: In 43 VSCC patients, there was a high mutation rate in both HPV-positive (73%) and HPV-negative (90%) disease with the two subgroups expressing distinct genetic profiles. HPV-positive tumors were characterized by oncogenic mutations in PIK3CA (27%), FGFR3 (14%), and PTEN (9%), whereas HPV-negative tumors were found to have mutations in TP53 (57%), HRAS (24%), PI3KCA (19%), and CDKN2A (14%). Mutation S249C in FGFR3 occurred in 14% of HPV-positive tumors. While there were notable differences in the occurrence of TP53, HRAS, PTEN, and FGFR3 mutations according to HPV status, only the rate of TP53 mutations was statistically significant (P = 0.0004). No significant difference in prognosis was found between patients with HPV-positive and HPV-negative VSCC.Conclusions: HPV-positive VSCC is characterized by oncogenic FGFR3 mutations that helps classify this subtype as a separate disease. Inhibitors of FGFR3 merit consideration as a therapeutic strategy in this neglected cancer in women. Clin Cancer Res; 23(15); 4501-10. ©2017 AACR.

HPV DNA in saliva from patients with SCC of the head and neck is specific for p16-positive oropharyngeal tumours.

BACKGROUND: Human papillomavirus (HPV) is an important cause of head and neck squamous cell carcinoma (HNSCC), especially in young people. These tumours overexpress p16 and respond well to treatment. The rapid detection of HPV in patients with HNSCC may expedite treatment when p16 status is not immediately available. METHODS: Saliva-based DNA collection kits and nested polymerase chain reaction (PCR) were used to determine the HPV status of 62 individuals with biopsy-proven HNSCC. Immunohistochemistry was used to determine tumour p16 status. RESULTS: A total of 62 patients were included in the study. Twenty-nine samples (47%) were positive for HPV DNA, the majority of which were high risk (HR) subtypes (79%). Patients who tested positive for HR HPV were more likely to have a tumour arising in the oropharynx compared to a non-oropharyngeal site (74 vs 26%; p = 0.003). A positive HR HPV saliva assay was 100% specific (95% CI 59-100%) and had a 100% positive predictive value (95% CI 75-100%) for a p16 positive tumour arising in the oropharynx. In contrast, a negative HR HPV assay had a 96% negative predictive value (95% CI 80-100%) for tumours arising in a non-oropharyngeal site. Independent of site, the saliva assay had a sensitivity of 77% (95% CI 54-91%) and a specificity of 94% (95% CI 77-99%), respectively, for a p16 positive tumour. CONCLUSION: We show that a saliva based assay is an effective method for detecting HPV in patients with HNSCC and that a positive HR HPV test is highly specific for p16 positive tumours arising in the oropharynx. This simple and rapid test could be used in cases where a biopsy of the primary tumour is not readily available.

Assessment of Circulating LncRNAs Under Physiologic and Pathologic Conditions in Humans Reveals Potential Limitations as Biomarkers.

Long non-coding RNAs (lncRNA) are a new class of regulatory molecules with diverse cellular functions. Recent reports have suggested that extracellular lncRNAs are detectable in human plasma and may serve as biomarkers. Here, we sought to investigate circulating lncRNAs as potential biomarkers for pulmonary arterial hypertension (PAH). Eighty-four lncRNAs, representing some of the most abundant and functionally relevant candidates identified in cellular studies, were assessed via RT-qPCR in plasma from PAH and healthy subjects. However, despite preamplification, the majority of lncRNAs were surprisingly undetectable or sporadically detectable, and showed no differential changes. Systematic characterization of plasma/RNA quality and technical performance via internal and external controls revealed no evidence of RNA degradation or RT-qPCR inhibition, and most lncRNAs were robustly detectable in pulmonary tissue. In plasma, lncRNA levels were the lowest among several different RNA species examined, and this was generalizable to other chronic and acute vascular conditions including coronary artery disease, acute coronary syndrome, and septic shock. In addition, two of three previously reported circulating lncRNA biomarker candidates were not detectable in any of the plasma samples. This study reveals new insight on the relative levels of lncRNAs in circulation, which has important implications for their potential development as biomarkers.

Both bulk and cancer stem cell subpopulations in triple-negative breast cancer are susceptible to Wnt, HDAC, and ERα coinhibition.

Development of targeted therapies for triple-negative breast cancer (TNBC, a more aggressive subtype) is an unmet medical need. We analyzed data from 887 patients with invasive breast cancer and observed that increased Wnt and histone deacetylase (HDAC) activities are associated with estrogen receptor 1 (ESR1) and progesterone receptor (PGR) repression, poor survival, and increased relapse. The inverse correlation between Wnt signaling and repression of ESR1 and PGR expression was found to be magnified in cancer stem cell (CSC) subpopulations in TNBC cell lines. Cosuppression of Wnt, HDAC, and ESR1 using clinically relevant low-dose inhibitors effectively repressed both bulk and CSC subpopulations and converted CSCs to non-CSCs in TNBC cells without affecting MCF-10A mammary epithelial cells.

Induction of Activating Transcription Factor 3 Is Associated with Cisplatin Responsiveness in Non-Small Cell Lung Carcinoma Cells.

Non-small cell lung carcinoma (NSCLC) is the most common cause of cancer deaths, with platin-based combination chemotherapy the most efficacious therapies. Gains in overall survival are modest, highlighting the need for novel therapeutic approaches including the development of next-generation platin combination regimens. The goal of this study was to identify novel regulators of platin-induced cytotoxicity as potential therapeutic targets to further enhance platin cytotoxicity. Employing RNA-seq transcriptome analysis comparing two parental NSCLC cell lines Calu6 and H23 to their cisplatin-resistant sublines, Calu6cisR1 and H23cisR1, activating transcription factor 3 (ATF3) was robustly induced in cisplatin-treated parental sensitive cell lines but not their resistant sublines, and in three of six tumors evaluated, but not in their corresponding normal adjacent lung tissue (0/6). Cisplatin-induced JNK activation was a key regulator of this ATF3 induction. Interestingly, in both resistant sublines, this JNK induction was abrogated, and the expression of an activated JNK construct in these cells enhanced both cisplatin-induced cytotoxicity and ATF3 induction. An FDA-approved drug compound screen was employed to identify enhancers of cisplatin cytotoxicity that were dependent on ATF3 gene expression. Vorinostat, a histone deacetylase inhibitor, was identified in this screen and demonstrated synergistic cytotoxicity with cisplatin in both the parental Calu6 and H23 cell lines and importantly in their resistant sublines as well that was dependent on ATF3 expression. Thus, we have identified ATF3 as an important regulator of cisplatin cytotoxicity and that ATF3 inducers in combination with platins are a potential novel therapeutic approach for NSCLC.

A phase I study of high-dose rosuvastatin with standard dose erlotinib in patients with advanced solid malignancies.

BACKGROUND: Synergistic cytotoxicity with high-dose statins and erlotinib has been demonstrated in preclinical models across a number of tumour types. In this phase I study, we evaluated the safety and potential anti-tumour activity of escalating doses of rosuvastatin in combination with the standard clinical dose of erlotinib in heavily pretreated patients with advanced solid tumours. METHODS: This was a single-center, phase I open-label study to determine the safety and recommended phase two dose (RPTD) of rosuvastatin in combination with 150 mg/day standard dose of erlotinib. Using a 3 + 3 study design and 28-day cycle, escalating doses of rosuvastatin from 1 to 8 mg/kg/day × 2 weeks (cycle 1) and 3 weeks (subsequent cycles) given concurrently with erlotinib were evaluated. In order to expand the experience and to gain additional safety and pharmacokinetic data, two expansions cohorts using concurrent or alternating weekly dosing regimens at the RPTD were also evaluated. RESULTS: All 24 patients enrolled were evaluable for toxicity, and 22 for response. The dose-limiting toxicity (DLT) of reversible muscle toxicity was seen at the 2 mg/kg/day dose level. Maximal tolerated dose (MTD) was determined to be 1 mg/kg/day. Thirty-three percent of patients developed at least 1 ≥ grade 2 muscle toxicity (rhabdomyolysis: 1/24, myalgia: 7/24) resulting in one study-related death. Durable stable disease for more than 170 days was seen in 25 % of patients that received concurrent treatment and were evaluable for response (n = 16). Plasma erlotinib levels on study were unaffected by the addition of rosuvastatin. CONCLUSIONS: The observed disease stabilization rate of 25 % with combination therapy in this heavily pretreated population is encouraging, however, the high levels of muscle toxicities observed limited this combination strategy.

Focal Adhesion Kinase Inhibitors in Combination with Erlotinib Demonstrate Enhanced Anti-Tumor Activity in Non-Small Cell Lung Cancer.

Blockade of epidermal growth factor receptor (EGFR) activity has been a primary therapeutic target for non-small cell lung cancers (NSCLC). As patients with wild-type EGFR have demonstrated only modest benefit from EGFR tyrosine kinase inhibitors (TKIs), there is a need for additional therapeutic approaches in patients with wild-type EGFR. As a key component of downstream integrin signalling and known receptor cross-talk with EGFR, we hypothesized that targeting focal adhesion kinase (FAK) activity, which has also been shown to correlate with aggressive stage in NSCLC, would lead to enhanced activity of EGFR TKIs. As such, EGFR TKI-resistant NSCLC cells (A549, H1299, H1975) were treated with the EGFR TKI erlotinib and FAK inhibitors (PF-573,228 or PF-562,271) both as single agents and in combination. We determined cell viability, apoptosis and 3-dimensional growth in vitro and assessed tumor growth in vivo. Treatment of EGFR TKI-resistant NSCLC cells with FAK inhibitor alone effectively inhibited cell viability in all cell lines tested; however, its use in combination with the EGFR TKI erlotinib was more effective at reducing cell viability than either treatment alone when tested in both 2- and 3-dimensional assays in vitro, with enhanced benefit seen in A549 cells. This increased efficacy may be due in part to the observed inhibition of Akt phosphorylation when the drugs were used in combination, where again A549 cells demonstrated the most inhibition following treatment with the drug combination. Combining erlotinib with FAK inhibitor was also potent in vivo as evidenced by reduced tumor growth in the A549 mouse xenograft model. We further ascertained that the enhanced sensitivity was irrespective of the LKB1 mutational status. In summary, we demonstrate the effectiveness of combining erlotinib and FAK inhibitors for use in known EGFR wild-type, EGFR TKI resistant cells, with the potential that a subset of cell types, which includes A549, could be particularly sensitive to this combination treatment. As such, further evaluation of this combination therapy is warranted and could prove to be an effective therapeutic approach for patients with inherent EGFR TKI-resistant NSCLC.

Angiotensin-Converting Enzyme and Aldosterone Serum Levels as Prognostic and Predictive Biomarkers for Cediranib in NCIC Clinical Trials Group Study BR.24.

UNLABELLED: Predictive biomarkers of benefit from angiogenesis inhibition are lacking. Serum angiotensin-converting enzyme (ACE) and aldosterone levels of non-small-cell lung cancer patients treated with chemotherapy with or without cediranib were evaluated. Low baseline ACE serum levels were prognostic of poor chemotherapy outcome and predictive of benefit from cediranib. Aldosterone increase with use of cediranib was correlated with better outcome. These results merit further studies. BACKGROUND: Treatment-induced hypertension might correlate with antiangiogenesis treatment efficacy. We evaluated the prognostic and predictive significance of angiotensin-converting enzyme (ACE) and aldosterone serum levels, regulators of blood pressure, in patients with advanced non-small-cell lung cancer (NSCLC) enrolled in the NCIC Clinical Trials Group BR.24 trial. Results of BR.24 demonstrated marginal efficacy of cediranib (an inhibitor of vascular endothelial growth factor receptors) combination with carboplatin-paclitaxel. PATIENTS AND METHODS: ACE and aldosterone were measured retrospectively using enzyme-linked immunosorbent assays at baseline and at time of treatment in serum samples of 226 and 176 of 296 enrolled patients, respectively. Cox regression was performed to correlate biomarkers and patient characteristics with overall survival (OS) and progression-free survival. RESULTS: Patients who received placebo with high baseline ACE levels (> 115 ng/mL) had significantly better OS compared with patients with low ACE (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.31-0.78; P = .002). Low ACE levels (≤ 115 ng/mL) were predictive of OS benefit from cediranib (P = .05). Aldosterone changes with treatment predicted differential OS between treatment arms, with an increased trend to associate with longer OS (HR, 0.49; 95% CI, 0.23-1.06; P = .07) for patients who received cediranib, but shorter OS (HR, 1.90; 95% CI, 0.93-3.87; P = .08) for patients who received placebo (interaction P = .01). CONCLUSION: Low baseline ACE levels were prognostic of poor OS and predictive of OS benefit from cediranib. An aldosterone level increase with treatment might also be predictive of OS benefit from cediranib. These biomarkers should be validated in additional antiangiogenic trials in NSCLC and other cancers.

miR Profiling Identifies Cyclin-Dependent Kinase 6 Downregulation as a Potential Mechanism of Acquired Cisplatin Resistance in Non-Small-Cell Lung Carcinoma.

UNLABELLED: To identify the mechanisms of cisplatin resistance, global microRNA (miR) expression was tested. The expression of miR-145 was consistently higher in resistant cells. The expression of cyclin-dependent kinase 6 (CDK6), a potential target of miR-145, was lower in resistant cells, and inhibition of CDK4/6 protected cells from cisplatin. Cell cycle inhibition, currently being tested in clinical trials, might be antagonistic to cisplatin and other cytotoxic drugs. BACKGROUND: Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related death. Platinum-based chemotherapeutic drugs are the most active agents in treating advanced disease. Resistance to these drugs is common and multifactorial; insight into the molecular mechanisms involved will likely enhance efficacy. MATERIALS AND METHODS: A set of NSCLC platinum-resistant sublines was created from the Calu6 cell line. Cell viability was quantified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Differentially expressed microRNAs (miRs) in these lines were identified using Affymetrix miR arrays. The potential genes targeted by these miRs were searched using the TargetScan algorithm. The expression levels of miRs and mRNA were tested using real-time polymerase chain reaction. RESULTS: miR-145 was reproducibly elevated in all the resistant sublines tested; however, modulation of miR-145 levels alone in these cells did not affect their response to cisplatin. A potential target of miR-145 is cyclin-dependent kinase 6 (CDK6), an important regulator of cell proliferation. The mRNA and protein levels of CDK6 were both downregulated in the resistant sublines. An inhibitor of CDK4/6 (PD0332991) protected parental NSCLC cells from cisplatin cytotoxicity. CONCLUSION: In the present study, we identified miRs differentially expressed in cisplatin-resistant cell lines, including miR-145. A predicted target of miR-145 is CDK6, and its expression was found to be downregulated in the resistant sublines, although not directly by miR-145. Inhibition of CDK6 antagonizes cisplatin-induced NSCLC cell cytotoxicity, suggesting that agents that inhibit CDK6 should be avoided during cisplatin therapy.