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Introduction To support their growth, cancer cells recapitulate latent developmental or physiological processes including those important for tissue repair, wound healing, and angiogenesis; however, reactivation of these processes is typically [...], In tumors, extravascular fibrin forms provisional scaffolds for endothelial cell (EC) growth and motility during angiogenesis. We report that fibrin-mediated angiogenesis was inhibited and tumor growth delayed following postnatal deletion of Tgfbr2 in the endothelium of Cdh5-[Cre.sup.ERT2] [Tgfbr2.sup.fl/fl] mice ([Tgfbr2.sup.iECKO]mice). ECs from [Tgfbr2.sup.iECKO] mice failed to upregulate the fibrinolysis inhibitor plasminogen activator inhibitor 1 (Serpinel, also known as PAI-1), due in part to uncoupled TGF-[beta]-mediated suppression of miR-30c. Bypassing TGF-[beta] signaling with vascular tropic nanoparticles that deliver miR-30c antagomiRs promoted PAI-1-dependent tumor growth and increased fibrin abundance, whereas miR-30c mimics inhibited tumor growth and promoted vascular-directed fibrinolysis in vivo. Using single-cell RNA-Seq and a NanoString miRNA array, we also found that subtypes of ECs in tumors showed spectrums of Serpinel and miR-30c expression levels, suggesting functional diversity in ECs at the level of individual cells; indeed, fresh EC isolates from lung and mammary tumor models had differential abilities to degrade fibrin and launch new vessel sprouts, a finding that was linked to their inverse expression patterns of miR-30c and Serpinel (i.e., miR-[30c.sup.hi] [Serpin1.sup.lo] ECs were poorly angiogenic and miR-[30c.sup.lo] Serpine[1.sup.hi] ECs were highly angiogenic). Thus, by balancing Serpinel expression in ECs downstream of TGF-[beta], miR-30c functions as a tumor suppressor in the tumor microenvironment through its ability to promote fibrin degradation and inhibit blood vessel formation.

Introduction Constitutively activated, mutant KRAS continuously stimulates downstream effector signaling and promotes nearly all cancer hallmarks (1). Hotspot mutations that predominately occur in codons 12 and 13 result in defective [...], BACKGROUND. The KRAS proto-oncogene is among the most frequently mutated genes in cancer, yet for 40 years it remained an elusive therapeutic target. Recently, allosteric inhibitors that covalently bind to KRAS G12C mutations have been approved for use in lung adenocarcinomas. Although responses are observed, they are often short-lived, thus making in-depth characterization of the mechanisms of resistance of paramount importance. METHODS. Here, we present a rapid-autopsy case of a patient who had a [KRAS.sup.G12C]-mutant lung adenocarcinoma who initially responded to a KRAS G12C inhibitor but then rapidly developed resistance. Using deep-RNA and whole-exome sequencing comparing pretreatment, posttreatment, and matched normal tissues, we uncover numerous mechanisms of resistance to direct KRAS inhibition. RESULTS. In addition to decreased KRAS G12C-mutant allele frequency in refractory tumors, we also found reactivation of the MAPK pathway despite no new mutations in KRAS or its downstream mediators. Tumor cell-intrinsic and non-cell autonomous mechanisms included increased complement activation, coagulation, and tumor angiogenesis, and several lines of evidence of immunologic evasion. CONCLUSION. Together, our findings reveal numerous mechanisms of resistance to current KRAS G12C inhibitors through enrichment of clonal populations, KRAS-independent downstream signaling, and diverse remodeling of the tumor microenvironment. FUNDING. Richard and Fran Duley, Jimmy and Kay Mann, the NIH, and the North Carolina Biotechnology Center.

Tumor xenograft models developed by transplanting human tissues or cells into immune-deficient mice are widely used to study human cancer response to drug candidates. However, immune-deficient mice are unfit for investigating the effect of immunotherapeutic agents on the host immune response to cancer (Morgan, 2012). Here, we describe the preparation of an orthotopic, syngeneic model of lung adenocarcinoma (LUAD), a subtype of non-small cell lung cancer (NSCLC), to study the antitumor effect of chemo and immunotherapeutic agents in an immune-competent animal. The tumor model is developed by implanting 344SQ LUAD cells derived from the metastases of Kras G12D ; p53 R172HΔG genetically engineered mouse model into the left lung of a syngeneic host (Sv/129). The 344SQ LUAD model offers several advantages over other models: 1) The immune-competent host allows for the assessment of the biologic effects of immune-modulating agents; 2) The pathophysiological features of the human disease are preserved due to the orthotopic approach; 3) Predisposition of the tumor to metastasize facilitates the study of therapeutic effects on primary tumor as well as the metastases ( Chen et al. , 2014 ). Furthermore, we also describe a treatment strategy based on Poly(2-oxazoline) micelles that has been shown to be effective in this difficult-to-treat tumor model ( Vinod et al. , 2020b )., Competing Interests: Competing interestsA.V.K. is co-inventor on patents pertinent to the subject matter of the present contribution and A.V.K. and M.S.P. have co-founders' interest in DelAqua Pharmaceuticals Inc. having intent of commercial development of POx based drug formulations. The other authors have no competing interests to report., (Copyright © 2021 The Authors; exclusive licensee Bio-protocol LLC.)

Many new drug development candidates are highly lipophilic compounds with low water solubility. This constitutes a formidable challenge for the use of such compounds for cancer therapy, where high doses and intravenous injections are needed ( Di et al. , 2012 ). Here, we present a poly(2-oxazoline) polymer (POx)-based nanoformulation strategy to solubilize and deliver hydrophobic drugs. POx micelles are prepared by a simple thin-film hydration method. In this method, the drug and polymer are dissolved in a common solvent and allowed to mix, following which the solvent is evaporated using mild heating conditions to form a thin film. The micelles form spontaneously upon hydration with saline. POx nanoformulation of hydrophobic drugs is unique in that it has a high drug loading capacity, which is superior to micelles of conventional surfactants. Moreover, multiple active pharmaceutical ingredients (APIs) can be included within the same POx micelle, thereby enabling the codelivery of binary as well as ternary drug combinations ( Han et al. , 2012 ; He et al. , 2016 )., Competing Interests: Competing interestsA.V.K. is co-inventor on patents pertinent to the subject matter of the present contribution and A.V.K. and M.S.P. have co-founders’ interest in DelAqua Pharmaceuticals Inc. having intent of commercial development of POx based drug formulations. The other authors have no competing interests to report., (Copyright © 2021 The Authors; exclusive licensee Bio-protocol LLC.)