Haiying Cheng

PARP inhibition selectively increases sensitivity to cisplatin in ERCC1-low non-small cell lung cancer cells.

Platinum compounds are the foundation of chemotherapy regimens for non-small cell lung cancer (NSCLC) despite poor response rates and limited response duration. It has been reported that tumor expression of excision repair cross-complementation group 1 (ERCC1), a key component in nucleotide excision repair, may correlate with clinical response to platinum agents. We found that most primary lung tumor specimens demonstrated a stronger protein expression of poly (adenosine diphosphate ribose) polymerases 1 (PARP1) than their normal counterparts. Therefore, we hypothesized that combining PARP inhibition with platinum compounds may be an approach to improve platinum-based therapy for NSCLC. Drug combination experiments revealed that two distinct PARP inhibitors, olaparib and veliparib, not only potentiated the cell killing by cisplatin but also conferred cytotoxicity as a single agent specifically in ERCC1-low HCC827 and PC9 but not in ERCC1-high A549 and H157 lung cancer cells. Moreover, small interfering RNA knockdown of ERCC1 in A549 and H157 cells increased their sensitivities to both cisplatin and olaparib in a synergistic manner in our model. Furthermore, mechanistic studies indicated that combined PARP inhibitor and cisplatin could lead to sustained DNA double-strand breaks, prolonged G2/M cell cycle arrest with distinct activation of checkpoint kinase 1 signaling and more pronounced apoptosis preferentially in lung cancer cells with low ERCC1 expression. Collectively, these data suggest that there is a synergistic relationship between PARP inhibition and low ERCC1 expression in NSCLC that could be exploited for novel therapeutic approaches in lung cancer therapy based on tumor ERCC1 expression.

RICTOR amplification defines a novel subset of patients with lung cancer who may benefit from treatment with mTORC1/2 inhibitors

UNLABELLED We identified amplification of RICTOR, a key component of the mTOR complex 2 (mTORC2), as the sole actionable genomic alteration in an 18-year-old never-smoker with lung adenocarcinoma. Amplification of RICTOR occurs in 13% of lung cancers (1,016 cases) in The Cancer Genome Atlas and at a similar frequency in an independent cohort of 1,070 patients identified by genomic profiling. In the latter series, 11% of cases harbored RICTOR amplification as the only relevant genomic alteration. Its oncogenic roles were suggested by decreased lung cancer cell growth both in vitro and in vivo with RICTOR ablation, and the transforming capacity of RICTOR in a Ba/F3-cell system. The mTORC1/2 inhibitors were significantly more active against RICTOR-amplified lung cancer cells as compared with other agents targeting the PI3K-AKT-mTOR pathway. Moreover, an association between RICTOR amplification and sensitivities to mTORC1/2 inhibitors was observed. The index patient has been treated with mTORC1/2 inhibitors that led to tumor stabilization for more than 18 months. SIGNIFICANCE RICTOR amplification may define a novel and unique molecular subset of patients with lung cancer who may benefit from treatment with mTORC1/2 inhibitors.

Immune checkpoint blockade in human cancer therapy: lung cancer and hematologic malignancies

Tumor immune evasion is one of the hallmarks of cancer, and expression of the B7 family of immune checkpoints (PD-L1, PD-L2, B7-H3, B7x and HHLA2) is one mechanism of immune evasion by tumors to suppress T-cell function. Antibodies blocking these interactions of B7-1/B7-2/CTLA-4 and PD-L1/PD-L2/PD-1 have had remarkable clinical success in several cancers and are less toxic than traditional chemotherapy. Even though only a small proportion of patients respond to checkpoint blockade, the duration of such responders due to immunological memory is remarkable and is longer than would be expected with any other agent in refractory disease. In this article, we review the therapeutic trials of blocking these pathways in human lung cancer and hematological malignancies.

Management of imatinib-related exacerbation of psoriasis in a patient with a gastrointestinal stromal tumour.

A 62‐year‐old woman with a pre‐existing psoriasis was treated with oral imatinib (400 mg/day) for a metastatic gastrointestinal stromal tumour. Within 4 weeks of starting therapy, she developed a guttate psoriasis flare. The eruption markedly improved within 2 weeks following cessation of imatinib. However, it recurred when imatinib was recommenced. She has been able to continue on imatinib (400 mg/day) with low‐dose oral methotrexate (12.5 mg/week) controlling the psoriasis.

HHLA2, a New Immune Checkpoint Member of the B7 Family, Is Widely Expressed in Human Lung Cancer and Associated with EGFR Mutational Status

Purpose: Immunotherapy with antibodies against B7/CD28 family members, including PD-1, PD-L1, and CTLA-4 has shifted the treatment paradigm for non–small cell lung carcinoma (NSCLC) with improved clinical outcome. HHLA2 is a newly discovered member of the family. By regulating T-cell function, HHLA2 could contribute to tumor immune suppression and thus be a novel target for cancer immunotherapy. There is limited information and critical need to characterize its expression profile and clinical significance in NSCLC. Experimental Design: We performed IHC with an HHLA2-specific antibody (clone 566.1) using tissue microarrays constructed from 679 NSCLC tumor tissues, including 392 cases in the discovery set and 287 cases in the validation cohort. We also studied clinicopathologic characteristics of these patients. Results: Overall, HHLA2 was not detected in most of normal lung tissue but expressed in 66% of NSCLC across different subtypes. In particular, EGFR-mutated NSCLC was significantly associated with higher tumor HHLA2 expression in both discovery (EGFR vs. WT: 76% vs. 53%, P = 0.01) and validation cohorts (89% vs. 69%, P = 0.01). In one of the two cohorts, HHLA2 expression was higher in lung adenocarcinoma as compared with squamous and large cell histology, non-Hispanic White versus Hispanics, and tumors with high tumor-infiltrating lymphocyte (TIL) density. In the multivariate analysis, EGFR mutation status and high TIL intensity were independently associated with HHLA2 expression in lung adenocarcinoma. Conclusions: HHLA2 is widely expressed in NSCLC and is associated with EGFR mutation and high TILs in lung adenocarcinoma. It is potentially a novel target for lung cancer immunotherapy. Clin Cancer Res; 23(3); 825–32. ©2016 AACR.

Emerging drugs for squamous cell lung cancer

Introduction: The management of advanced NSCLC has been shifted by histology-driven treatment and molecularly targeted therapy, especially in lung adenocarcinoma. However, as the second most common histology in NSCLC, the treatment options for squamous cell lung cancer (SQCLC) remain very limited. Areas covered: The review first discusses the role of histology in management of NSCLC and new cytotoxic agents in SQCLC, and then addresses genomic characterization and potential molecular targets in SQCLC. The article then provides an overview for several major categories of novel molecularly targeted therapies and immune-based strategies with particular attention to ongoing SQCLC trials. Expert opinion: The key challenges in drug development are to uncover novel actionable targets and to identify predictive biomarkers. Progress in genomic analysis has identified some promising targetable genes and oncogenic pathways in SQCLC with a wave of targeted agents being tested in clinical trials. Immunotherapy has also raised great interest in management of SQCLC, especially agents targeting immune check points, cytotoxic T-lymphocyte antigen-4, programmed death-1 receptor and its ligands. Better understanding of tumor biology and development of novel targeted therapies will help to facilitate more effective personalized therapy for patients with this devastating illness.

Cell cycle inhibitors for the treatment of NSCLC

Introduction: Lung cancer remains to be the leading cause of cancer-related death worldwide. Treatment of lung cancer still poses a significant challenge. Cell cycle is a tightly integrated process and is frequently aberrant in lung cancer. Cell cycle inhibitors have emerged as novel therapeutics, in anticipation of overcoming the unrestricted cell division and growth in lung cancer. Areas covered: In this article, we first address the potential roles of cell cycle proteins and cell cycle deregulation in the development of lung cancer. The review then provides an overview for several major categories of cell cycle inhibitors with particular attention to their tolerability and disease control in early phases of lung cancer trials. Expert opinion: Targeted agents against different components of cell cycle regulation, such as cyclin-dependent kinase, polo-like kinase, checkpoint kinase and aurora kinase, are currently in clinical development for lung cancer management. Their clinical benefits remain to be defined. When evaluated as single agents in lung cancer, cell cycle inhibitors are often associated with limited clinical activity and tolerable toxicities. The key challenges in the drug development are to understand resistance mechanisms and to identify predictive biomarkers that can potentially guide patient selection and optimize the utility of these targeted inhibitors.

Thymidylate synthase expression and molecular alterations in adenosquamous carcinoma of the lung.

Thymidylate synthase expression is known to be higher in squamous cell carcinoma than in adenocarcinoma of the lung. It is thought that this is the reason for the poor efficacy of pemetrexed in squamous cell carcinoma. However, there is limited data on thymidylate synthase expression in adenosquamous carcinoma, a distinct subtype of lung cancer containing both squamous and glandular differentiation. Furthermore, molecular alterations like epidermal growth factor receptor and Kirsten rat sarcoma 2 viral oncogene homolog mutations, which are seen in adenocarcinomas, are not well understood in mixed histology tumors such as adenosquamous carcinoma. In our study, we sought to better characterize adenosquamous tumors of the lung. Using immunohistochemistry to evaluate thymidylate synthase protein levels, we found that the expression of thymidylate synthase in these mixed tumors roughly parallel that of squamous cell carcinoma, instead of falling in between squamous cell and adenocarcinoma. Of note, in adenosquamous samples, the expression of thymidylate synthase was more closely correlated within the two components than would be expected by random chance alone. Also, we had a relatively high rate of epidermal growth factor receptor (11%) and Kirsten rat sarcoma 2 viral oncogene homolog (33%) mutations in these specimens, with the mutations showing convergence in both the glandular and squamous components upon microdissection. Our results indicate that adenosquamous carcinomas are not simple mixtures of their two histological components; they rather behave as their own entity, and it is important to further understand their behavior. Given the similarity of thymidylate synthase expression between squamous cell and adenosquamous carcinoma, and that thymidylate synthase is the main target of pemetrexed, we extrapolate that pemetrexed may also have inferior clinical activity in adenosquamous carcinoma.

Emerging treatment for advanced lung cancer with EGFR mutation

Introduction: Lung cancer is the leading cause of cancer-related death worldwide. It is usually diagnosed at advanced stage for which platinum-based chemotherapy had been the standard approach, although with limited clinical benefits. Discovery of oncogenic EGFR mutations in lung cancer have shifted the treatment paradigm with molecularly targeted therapies. Areas covered: EGFR tyrosine kinase inhibitors (TKIs) have become the first-line choice in patients with advanced NSCLC harboring EGFR activating mutations. However, resistance to targeted therapy develops inevitably during the course of treatment. Multiple mechanisms of acquired resistance have been discovered, most commonly the secondary mutation of T790M in exon 20. The second- and third-generation EGFR TKIs are holding promise to overcome T790M-associated acquired resistance and currently being tested in clinical trials. In this article, we focus on the emerging approaches to overcome the different mechanisms of resistance to targeted therapies in patients with EGFR-mutant advanced NSCLC. Expert opinion: It is essential to uncover the complex mechanisms underlying the progression of lung cancer after upfront EGFR TKIs. Next generation, in particular, the third generations of EGFR TKIs have been developed against acquired T790M mutation with promising clinical activity and better toxicity profile. Combination of targeted therapies has also been explored. Further studies are needed to detect the real-time changes of the resistance mechanisms and to develop new therapeutic strategies for lung cancer patients with EGFR mutations.

Recent advances in the management of pulmonary sarcomatoid carcinoma

ABSTRACT Pulmonary sarcomatoid carcinoma (PSC) is a unique and biologically fascinating group of poorly differentiated non-small cell lung cancer (NSCLC), however it is highly aggressive with poor overall survival compared to other types of NSCLC. Radical surgery remains the standard of care for early localized disease but this has shown to result in high recurrence rates. Traditional palliative chemotherapy is associated with poor response in advanced/metastatic PSC. Recent comprehensive genetic studies and clinical observations are starting to elucidate the key oncogenic underpinnings of PSC. In particular, the recent identification of frequent genetic alterations of the MET gene leading to exon 14 skipping have yielded actionable targets for intervention with available MET inhibitors for a subset of PSC patients. Immunotherapy against immune checkpoints, such as anti-PD1/PD-L1 agents, have also raised great interest for the management of PSC. A growing understanding of the molecular pathogenesis of PSC is rapidly yielding novel approaches for the treatment of this deadly malignancy.