Imaging of apoptosis can allow noninvasive assessment of disease states and response to therapeutic intervention for a variety of diseases. The purpose of this study was to develop and evaluate a multimodal nanoplatform for the detection of apoptosis. Methods: To modulate the pharmacokinetics of annexin A5, a 36-kDa protein that binds specifically with phosphatidylserine, annexin A5 was conjugated to polyethylene glycol–coated, core-cross-linked polymeric micelles (CCPMs) dually labeled with near-infrared fluorescence fluorophores and a radioisotope (¹¹¹In). To evaluate the specificity of the binding of annexin A5-CCPM to apoptotic cells, both fluorescence microscopy and cell-binding studies were performed in vitro. Pharmacokinetics, biodistribution, dual nuclear and optical imaging, and immunohistochemical studies were performed in 2 xenografted tumor models to evaluate the potential applications of annexin A5-CCPM. Results: In cell-based studies, annexin A5-CCPM exhibited strongly specific binding to apoptotic tumor cells. This binding could be efficiently blocked by annexin A5. In mice, annexin A5-CCPM displayed a mean elimination half-life of 12.5 h. The mean initial concentration in blood was 22.4% of the injected dose/mL, and annexin A5-CCPM was mainly distributed in the central blood compartment. In mice bearing EL4 lymphoma treated with cyclophosphamide and etoposide and in mice bearing MDA-MB-468 breast tumors treated with poly(L-glutamic acid)-paclitaxel and cetuximab (IMC-C225) anti–epidermal growth factor receptor antibody, the tumor apoptosis was clearly visualized by both SPECT and fluorescence molecular tomography. In contrast, there was little accumulation of this nanoradiotracer in the tumors of untreated mice. The biodistribution data were consistent with the imaging data, with tumor-to-muscle and tumor-to-blood ratios of 38.8 and 4.1, respectively, in treated mice, and 14.8 and 2.2, respectively, in untreated mice bearing EL4 lymphoma. Moreover, further studies demonstrated that the conventional ^99mTc-labeled hydrazinonicotinamide annexin A5 and the plain CCPM control exhibited significantly lower uptake in the tumors of the treated mice than annexin A5-CCPM. Immunohistochemistry staining study showed that radioactivity count correlated with fluorescence signal from the nanoparticles, and both signals colocalized with the region of tumor apoptosis. Conclusion: Annexin A5-CCPM allowed visualization of tumor apoptosis by both nuclear and optical techniques. The complementary information acquired with multiple imaging techniques should be advantageous in assessing and validating early response to therapy.

Lack of sustained response to therapeutic agents in patients with KRAS-mutant lung cancer poses a major challenge and arises partly due to intratumor heterogeneity that defines phenotypically distinct tumor subpopulations. To attain better therapeutic outcomes, it is important to understand the differential therapeutic sensitivities of tumor cell subsets. Epithelial-mesenchymal transition is a biological phenomenon that can alter the state of cells along a phenotypic spectrum and cause transcriptional rewiring to produce distinct tumor cell subpopulations. We utilized functional shRNA screens, in in vitro and in vivo models, to identify and validate an increased dependence of mesenchymal tumor cells on cyclin-dependent kinase 4 (CDK4) for survival, as well as a mechanism of resistance to MEK inhibitors. High zinc finger E-box binding homeobox 1 levels in mesenchymal tumor cells repressed p21, leading to perturbed CDK4 pathway activity. Increased dependence on CDK4 rendered mesenchymal cancer cells particularly vulnerable to selective CDK4 inhibitors. Coadministration of CDK4 and MEK inhibitors in heterogeneous tumors effectively targeted different tumor subpopulations, subverting the resistance to either single-agent treatment.

Purpose: Our understanding of the immunopathology of resectable non–small cell lung cancer (NSCLC) is still limited. Here, we explore immune programs that inform of tumor immunity and response to neoadjuvant chemotherapy and chemoimmunotherapy in localized NSCLC. Experimental Design: Targeted immune gene sequencing using the HTG Precision Immuno-Oncology panel was performed in localized NSCLCs from three cohorts based on treatment: naïve (n = 190), neoadjuvant chemotherapy (n = 38), and neoadjuvant chemoimmunotherapy (n = 21). Tumor immune microenvironment (TIME) phenotypes were based on the location of CD8+ T cells (inflamed, cold, excluded), tumoral PD-L1 expression (<1% and ≥1%), and tumor-infiltrating lymphocytes (TIL). Immune programs and signatures were statistically analyzed on the basis of tumoral PD-L1 expression, immune phenotypes, and pathologic response and were cross-compared across the three cohorts. Results: PD-L1–positive tumors exhibited increased signature scores for various lymphoid and myeloid cell subsets (P < 0.05). TIME phenotypes exhibited disparate frequencies by stage, PD-L1 expression, and mutational burden. Inflamed and PD-L1+/TILs+ NSCLCs displayed overall significantly heightened levels of immune signatures, with the excluded group representing an intermediate state. A cytotoxic T-cell signature was associated with favorable survival in neoadjuvant chemotherapy–treated NSCLCs (P < 0.05). Pathologic response to chemoimmunotherapy was positively associated with higher expression of genes involved in immune activation, chemotaxis, as well as T and natural killer cells (P < 0.05 for all). Among the three cohorts, chemoimmunotherapy-treated NSCLCs exhibited the highest scores for various immune cell subsets including T effector and B cells (P < 0.05). Conclusions: Our findings highlight immune gene programs that may underlie host tumor immunity and response to neoadjuvant chemotherapy and chemoimmunotherapy in resectable NSCLC.

The aggressive variant prostate cancer molecular profile (AVPC-m), composed of combined defects in TP53, RB1 and PTEN, characterizes a subset of prostate cancers linked to androgen indifference and platinum sensitivity. To contribute to the optimization of the AVPC-m assessment for inclusion in prospective clinical trials, we investigated the status of the AVPC-m components in 28 patient tumor-derived xenografts (PDXs) developed at MDACC. We subjected single formalin-fixed, paraffin-embedded (FFPE) blocks from each PDX to immunohistochemistry (IHC), targeted next-generation genomic sequencing (NGS) and Clariom-S Affymetrix human microarray expression profiling. Standard validated IHC assays and a 10% labeling index cutoff resulted in high reproducibility across three separate laboratories and three independent readers for all tumor suppressors, as well as strong correlations with loss-of-function transcriptional scores (LOF-TS). Adding intensity assessment to labeling indices strengthened the association between IHC results and LOF-TS for TP53 and RB1, but not for PTEN. For TP53, genomic alterations determined by NGS had slightly higher agreement scores with LOF-TS than aberrant IHC, while for RB1 and PTEN, NGS and IHC determinations resulted in similar agreement scores with LOF-TS. Nonetheless, our results indicate that the AVPC-m components can be assessed reproducibly by IHC using various widely available standardized assays.

The integrated stress response (ISR) is an adaptive pathway hijacked by cancer cells to survive cellular stresses in the tumor microenvironment. ISR activation potently induces PD-L1, leading to suppression of antitumor immunity. In this study, we sought to uncover additional immune checkpoint proteins regulated by the ISR to elucidate mechanisms of tumor immune escape. The ISR coordinately induced cluster of differentiation 155 (CD155) and PD-L1, enhancing translation of both immune checkpoint proteins through bypass of inhibitory upstream open reading frames in their 5′ untranslated regions. Analysis of primary human lung tumors identified a significant correlation between expression of PD-L1 and CD155. ISR activation accelerated tumorigenesis and inhibited T-cell function, which could be overcome by combining PD-1 and TIGIT blockade with the ISR inhibitor ISRIB. This study uncovers a mechanism by which two immune checkpoint proteins are coordinately regulated and suggests a therapeutic strategy for patients with lung cancer. Significance: The integrated stress response represents a targetable axis to improve the efficacy of immunotherapy in lung cancer by inhibiting the coordinated translational regulation of the PD-L1/PD-1 and CD155/TIGIT immune checkpoint pathways.