Yifan Wang

Multivalent bi-specific nanobioconjugate engager for targeted cancer immunotherapy

Tumour-targeted immunotherapy offers the unique advantage of specific tumouricidal effects with reduced immune-associated toxicity. However, existing platforms suffer from low potency, inability to generate long-term immune memory and decreased activities against tumour-cell subpopulations with low targeting receptor levels. Here we adopted a modular design approach that uses colloidal nanoparticles as substrates to create a multivalent bi-specific nanobioconjugate engager (mBiNE) to promote selective, immune-mediated eradication of cancer cells. By simultaneously targeting the human epidermal growth factor receptor 2 (HER2) expressed by cancer cells and pro-phagocytosis signalling mediated by calreticulin, the mBiNE stimulated HER2-targeted phagocytosis and produced durable antitumour immune responses against HER2-expressing tumours. Interestingly, although the initial immune activation mediated by the mBiNE was receptor dependent, the subsequent antitumour immunity also generated protective effects against tumour-cell populations that lacked the HER2 receptor. Thus, the mBiNE represents a new targeted, nanomaterial-immunotherapy platform to stimulate innate and adaptive immunity and promote a universal antitumour response.

Hsp90 Inhibitor Ganetespib Sensitizes Non-Small Cell Lung Cancer to Radiation but Has Variable Effects with Chemoradiation

Purpose: HSP90 inhibition is well known to sensitize cancer cells to radiation. However, it is currently unknown whether additional radiosensitization could occur in the more clinically relevant setting of chemoradiation (CRT). We used the potent HSP90 inhibitor ganetespib to determine whether it can enhance CRT effects in NSCLC. Experimental Design: We first performed in vitro experiments in various NSCLC cell lines combining radiation with or without ganetespib. Some of these experiments included clonogenic survival assay, DNA damage repair, and cell-cycle analysis, and reverse-phase protein array. We then determined whether chemotherapy affected ganetespib radiosensitization by adding carboplatin–paclitaxel to some of the in vitro and in vivo xenograft experiments. Results: Ganetespib significantly reduced radiation clonogenic survival in a number of lung cancer cell lines, and attenuated DNA damage repair with irradiation. Radiation caused G2–M arrest that was greatly accentuated by ganetespib. Ganetespib with radiation also dose-dependently upregulated p21 and downregulated pRb levels that were not apparent with either drug or radiation alone. However, when carboplatin–paclitaxel was added, ganetespib was only able to radiosensitize some cell lines but not others. This variable in vitro CRT effect was confirmed in vivo using xenograft models. Conclusions: Ganetespib was able to potently sensitize a number of NSCLC cell lines to radiation but has variable effects when added to platinum-based doublet CRT. For optimal clinical translation, our data emphasize the importance of preclinical testing of drugs in the context of clinically relevant therapy combinations. Clin Cancer Res; 22(23); 5876–86. ©2016 AACR.

RAD50 expression is associated with poor clinical outcomes after radiotherapy for resected non-small cell lung cancer

Purpose: Although postoperative radiotherapy is often used to maintain local control after surgical resection and chemotherapy for locally advanced non–small cell lung cancer (NSCLC), both locoregional failure and distant metastasis remain problematic. The mechanisms of therapeutic resistance remain poorly understood. Experimental Design: We used reverse-phase protein arrays (RPPA) to profile the baseline expression of 170 total and phosphorylated proteins in 70 NSCLC cell lines to categorize pathways that may contribute to radiation resistance. Significant markers identified by RPPA were further analyzed in tissue microarrays (TMA) of specimens from 127 patients with NSCLC who had received surgery before receiving postoperative radiotherapy. Cox regression analysis and log-rank tests were used to identify potential predictive factors. We then validated the biological function of the markers in NSCLC cell lines in vitro. Results: Of the 170 proteins or phospho-proteins profiled, a subset of 12 proteins was found to correlate with radiation response parameters. TMA analysis of the 12 proteins showing the greatest differences in expression in the RPPA analysis demonstrated that RAD50 had the strongest correlation with distant relapse-free survival, locoregional relapse-free survival, and disease-free survival in patients with NSCLC. We confirmed that knockdown of RAD50 sensitized NSCLC cells to radiation and that upregulation of RAD50 increased radioresistance in in vitro experiments. Conclusions: Upregulated RAD50 may be a predictor of radioresistance in patients with lung cancer who received radiotherapy. Clin Cancer Res; 24(2); 341–50. ©2017 AACR.

Drug-induced RAF dimerization is independent of RAS mutation status and does not lead to universal MEK dependence for cell survival in head and neck cancers

Treatments for recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) have limited efficacy. One potential therapeutic target for HNSCC is the RAS/RAF/MEK/ERK cascade, which is one of the major signaling pathways for HNSCC cell survival. In HNSCC, RAS can be activated either by HRAS mutation or by upstream signaling. The ABL inhibitor nilotinib acts as a weak RAF inhibitor that induces RAF dimerization and subsequent activation of MEK/ERK in other cancer cell lines with activated RAS, leading to an unexpected dependence on MEK/ERK for cell survival. We hypothesized that nilotinib and the MEK inhibitor MEK162 would be synergistic in HNSCC cell lines owing to the frequent activation of RAS. We treated HNSCC cell lines with nilotinib and performed immunoblotting and cell-viability experiments. We used an orthotopic mouse model to assess synergistic effects in vivo. Nilotinib induced significant BRAF-CRAF heterodimerization and ERK activation irrespective of RAS mutation status. In cell-viability assays, nilotinib synergized with MEK162. MEK162 alone induced G1 arrest that was minimally enhanced by nilotinib. In the mouse model, treatment with MEK162 alone or combined with nilotinib led to tumor growth inhibition. In HNSCC, nilotinib-induced RAF dimerization is independent of RAS mutation status, but this dimerization does not lead to MEK dependence for cell survival in all HNSCC cell lines. MEK inhibition alone leads to decreased proliferation both in vitro and in vivo. Although nilotinib has some synergistic effects with MEK162, other agents may be more effective against HNSCC when combined with MEK162.

Combining Immunotherapy and Radiotherapy for Cancer Treatment: Current Challenges and Future Directions

Since the approval of anti-CTLA4 therapy (ipilimumab) for late-stage melanoma in 2011, the development of anticancer immunotherapy agents has thrived. The success of many immune-checkpoint inhibitors has drastically changed the landscape of cancer treatment. For some types of cancer, monotherapy for targeting immune checkpoint pathways has proven more effective than traditional therapies, and combining immunotherapy with current treatment strategies may yield even better outcomes. Numerous preclinical studies have suggested that combining immunotherapy with radiotherapy could be a promising strategy for synergistic enhancement of treatment efficacy. Radiation delivered to the tumor site affects both tumor cells and surrounding stromal cells. Radiation-induced cancer cell damage exposes tumor-specific antigens that make them visible to immune surveillance and promotes the priming and activation of cytotoxic T cells. Radiation-induced modulation of the tumor microenvironment may also facilitate the recruitment and infiltration of immune cells. This unique relationship is the rationale for combining radiation with immune checkpoint blockade. Enhanced tumor recognition and immune cell targeting with checkpoint blockade may unleash the immune system to eliminate the cancer cells. However, challenges remain to be addressed to maximize the efficacy of this promising combination. Here we summarize the mechanisms of radiation and immune system interaction, and we discuss current challenges in radiation and immune checkpoint blockade therapy and possible future approaches to boost this combination.

Log odds of positive lymph nodes may predict survival benefit in patients with node-positive non-small cell lung cancer

OBJECTIVESnThe number of positive lymph nodes (npLNs) and the lymph node ratio [LNR; npLNs/number of resected LNs] are useful for predicting survival among patients with non-small cell lung cancer (NSCLC). Here we compared the relative effectiveness of npLNs, LNR, and the log odds of positive lymph nodes (LODDS) to predict overall survival (OS) and cancer-specific survival (CSS) among patients with node-positive NSCLC.nnnMATERIALS AND METHODSnWe identified 5289 patients with NSCLC and lymph node involvement who had lobectomy or pneumonectomy in 2010-2013 from the Surveillance Epidemiology and End Results (SEER) database. Potential associations between npLNs, LNR, and LODDS with overall survival (OS) and cancer-specific survival (CSS) were assessed with Cox regression analysis. The goodness of fit of npLNs, LNR, and LODDS was compared with the -2 log-likelihood ratio (-2LLR) and by differences in Akaikes information criterion scores (ΔAIC). Tree-based recursive partitioning was applied to split ratio-based variables (LNR and LODDS) into low- and high-risk groups. Kaplan-Meier actuarial estimates of OS and CSS in the various npLNs, LNR, and LODDS subgroups were compared with log-rank tests.nnnRESULTS AND CONCLUSIONnOf 5289 patients, 2297 (43.3%) had <10 LNs retrieved and 2992 (56.6%) had ≥10 LNs harvested. Multivariate Cox analysis adjusted for significant factors indicated that LODDS, npLNs, and LNR were independent risk factors for OS and CSS. A LODDS model had the best fit compared with LNR or npLN models in predicting OS and CSS (Pu202f<u202f0.001, ΔAICu202f=u202f0). LODDS was slightly superior to LNR for patients with <10 resected LNs, and LNR was slightly superior to LODDS for patients with ≥10 resected LNs (Pu202f<u202f0.001). Higher LODDS was associated with worse OS and worse CSS (log-rank P for both <0.001). LODDS and LNR staging schemes outperformed those of npLNs for predicting OS and CSS.

Survival Patterns for Patients with Resected N2 Non-Small Cell Lung Cancer and Postoperative Radiotherapy: A Prognostic Scoring Model and Heat Map Approach.

Introduction: The positive‐to‐resected lymph node ratio (LNR) predicts survival in many cancers, but little information is available on its value for patients with N2 NSCLC who receive postoperative radiotherapy (PORT) after resection. We tested the applicability of prognostic scoring models and heat mapping to predict overall survival (OS) and cancer‐specific survival (CSS) in patients with resected N2 NSCLC and PORT. Methods: Our test cohort comprised patients identified from the Surveillance, Epidemiology, and End Results database with N2 NSCLC who received resection and PORT in 2000–2014. Prognostic scoring models were developed to predict OS and CSS using Cox regression; heat maps were constructed with corresponding survival probabilities. Recursive partitioning analysis was applied to the Surveillance, Epidemiology, and End Results data to identify the optimal LNR cutoff point. Models and cutoff points were further tested in 183 similar patients treated at The University of Texas M. D. Anderson Cancer Center in 2000–2015. Results: Multivariate analyses revealed that low LNR independently predicted better OS and CSS in patients with resected N2 NSCLC who received PORT. Conclusions: LNR can be used to predict survival of patients with resected N2 NSCLC followed by PORT. This approach, which to our knowledge is the first application of heat mapping of positive and negative lymph nodes, was effective in estimating 3‐, 5‐, and 10‐year OS probabilities.

Mutant LKB1 Confers Enhanced Radiosensitization in Combination with Trametinib in KRAS-Mutant Non–Small Cell Lung Cancer

Purpose: The MEK inhibitor trametinib radiosensitizes KRAS-mutant non–small cell lung cancer (NSCLC) and is being tested clinically with chemoradiation. However, variability in response to trametinib suggests that additional pathways are involved. The mechanism of resistance to trametinib radiosensitization is still unknown. Experimental Design: We used a panel of KRAS-mutant NSCLC cells and tested the radiosensitization effects of trametinib by clonogenic survival assay. Then, we investigated the mechanisms underlying the resistance to the combination therapy through several knockout and overexpression systems. Finally, we validated our findings in syngeneic mouse models in a treatment setting that mimicked the standard of care in the clinic. Results: Radiosensitization by trametinib was effective only in KRAS-LKB1–mutated cells with wild-type (WT) p53, and we found that restoring LKB1 expression in those cells blocked that sensitization. Trametinib and radiotherapy both induced senescence in a p53-dependent manner, but in WT LKB1 cells, the combination also activated the AMPK-autophagy pathway to rescue damaged cells from senescence. LKB1-knockout or autophagy inhibition in WT LKB1 cells potentiated trametinib radiosensitization. In syngeneic animal models of Kras-mutant lung tumors, Lkb1-knockout tumors were resistant to trametinib and chemoradiation given separately, but the combination greatly controlled tumor growth and prolonged survival. Conclusions: The LKB1 mutation in KRAS-mutant NSCLC conferred enhanced radiosensitization in combination with trametinib. The WT LKB1 could activate autophagy through AMPK pathway to induce resistance to the combination of trametinib and radiation. The KRAS-LKB1 mutation could potentially be a biomarker to select patients for trametinib and radiotherapy combination therapy. Clin Cancer Res; 24(22); 5744–56. ©2018 AACR.