Intratumoral Biosynthesis of Gold Nanoclusters by Pancreatic Cancer to Overcome Delivery Barriers to Radiosensitization.

Nanoparticle delivery to solid tumors is a prime challenge in nanomedicine. Here, we approach this challenge through the lens of biogeochemistry, the field that studies the flow of chemical elements within ecosystems as manipulated by living cellular organisms and their environments. We leverage biogeochemistry concepts related to gold cycling against pancreatic cancer, considering mammalian organisms as drivers for gold nanoparticle biosynthesis. Sequestration of gold nanoparticles within tumors has been demonstrated as an effective strategy to enhance radiotherapy; however, the desmoplasia of pancreatic cancer impedes nanoparticle delivery. Our strategy overcomes this barrier by applying an atomic-scale agent, ionic gold, for intratumoral gold nanoparticle biosynthesis. Our comprehensive studies showed the cancer-specific synthesis of gold nanoparticles from externally delivered gold ions in vitro and in a murine pancreatic cancer model in vivo; a substantial colocalization of gold nanoparticles (GNPs) with cancer cell nuclei in vitro and in vivo; a strong radiosensitization effect by the intracellularly synthesized GNPs; a uniform distribution of in situ synthesized GNPs throughout the tumor volume; a nearly 40-day total suppression of tumor growth in animal models of pancreatic cancer treated with a combination of gold ions and radiation that was also associated with a significantly higher median survival versus radiation alone (235 vs 102 days, respectively).

Clinical and Dosimetric Results of Proton or Photon Radiation Therapy for Large (>5 cm) Hepatocellular Carcinoma: A Retrospective Analysis.

PURPOSE: Our purpose was to report the clinical and dosimetric attributes of patients with large unresectable hepatocellular carcinoma (HCC) undergoing proton or photon radiation therapy. METHODS AND MATERIALS: We retrospectively analyzed the outcomes and dosimetric indices of 159 patients with >5 cm nonmetastatic HCC who underwent definitive radiation therapy using either protons (N = 105) or photons (N = 54) between 2014 and 2018. Additional photon plans were performed in the 105 proton-treated patients using the same dose prescription criteria for intragroup dosimetric comparison. RESULTS: After a median follow-up of 47 months, patients with biologically effective dose (BED10) ≥ 75 Gy exhibited significantly better local control (LC; 2-year: 85.6% vs 20.5%; P < .001), progression-free survival (PFS; median, 7.4 vs 3.2 months; P < .001), and overall survival (OS; median, 18.1 vs 7.3 months; P < .001) compared with those with BED10 < 75 Gy. Notably, proton-treated patients had a significantly higher BED10 (96 vs 67 Gy; P < .001) and improved LC (2-year: 88.5% vs 33.8%; P < .001), PFS (median, 7.4 vs 3.3 months; P = .001), and OS (median, 18.9 vs 8.3 months; P < .001) than those undergoing photon radiation therapy. Furthermore, patients treated with protons had significantly lower V1 of the liver (P < .001), mean upper gastrointestinal tract dose (P < .001), and mean splenic dose (P < .001), with significantly decreased incidences of radiation-induced liver disease (P = .007), grade ≥3 upper gastrointestinal bleeding (P = .001), and grade ≥3 lymphopenia (P = .003). On multivariate analysis, proton radiation therapy consistently correlated with superior LC (P < .001), PFS (P < .001), and OS (P < .001). In intragroup dosimetric comparison, photon plans demonstrated significantly higher mean liver dose (P < .001) compared with actually delivered proton treatments, and 72 (69%) of them had mean liver dose exceeding 28 Gy, which necessitated target dose de-escalation. CONCLUSIONS: In the context of large HCC radiation therapy, a higher target BED10 was associated with improved outcomes. Notably, proton therapy has demonstrated the capability to deliver ablative doses while also being accompanied by fewer instances of severe toxicity.

Dual enhancement in the radiosensitivity of prostate cancer through nanoparticles and chemotherapeutics.

Background: Radiotherapy (RT) is an essential component in the treatment regimens for many cancer patients. However, the dose escalation required to improve curative results is hindered due to the normal tissue toxicity that is induced. The introduction of radiosensitizers to RT treatment is an avenue that is currently being explored to overcome this issue. By introducing radiosensitizers into tumor sites, it is possible to preferentially enhance the local dose deposited. Gold nanoparticles (GNPs) are a potential candidate that have shown great promise in increasing the radiosensitivity of cancer cells through an enhancement in DNA damage. Furthermore, docetaxel (DTX) is a chemotherapeutic agent that arrests cells in the G2/M phase of the cell cycle, the phase most sensitive to radiation damage. We hypothesized that by incorporating DTX to GNP-enhanced radiotherapy treatment, we could further improve the radiosensitization experienced by cancer cells. To assess this strategy, we analyzed the radiotherapeutic effects on monolayer cell cultures in vitro, as well as on a mice prostate xenograft model in vivo while using clinically feasible concentrations for both GNPs and DTX. Results: The introduction of DTX to GNP-enhanced radiotherapy further increased the radiotherapeutic effects experienced by cancer cells. A 38% increase in DNA double-strand breaks was observed with the combination of GNP/DTX vs GNP alone after a dose of 2 Gy was administered. In vivo results displayed significant reduction in tumor growth over a 30-day observation period with the treatment of GNP/DTX/RT when compared to GNP/RT after a single 5 Gy dose was given to mice. The treatment strategy also resulted in 100% mice survival, which was not observed for other treatment conditions. Conclusions: Incorporating DTX to work in unison with GNPs and RT can increase the efficacy of RT treatment. Our study suggests that the treatment strategy could improve tumor control through local dose enhancement. As the concentrations used in this study are clinically feasible, there is potential for this strategy to be translated into clinical settings. Supplementary Information: The online version contains supplementary material available at 10.1186/s12645-023-00228-0.

Premature senescence and cardiovascular disease following cancer treatments: mechanistic insights.

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality, especially among the aging population. The "response-to-injury" model proposed by Dr. Russell Ross in 1999 emphasizes inflammation as a critical factor in atherosclerosis development, with atherosclerotic plaques forming due to endothelial cell (EC) injury, followed by myeloid cell adhesion and invasion into the blood vessel walls. Recent evidence indicates that cancer and its treatments can lead to long-term complications, including CVD. Cellular senescence, a hallmark of aging, is implicated in CVD pathogenesis, particularly in cancer survivors. However, the precise mechanisms linking premature senescence to CVD in cancer survivors remain poorly understood. This article aims to provide mechanistic insights into this association and propose future directions to better comprehend this complex interplay.

Next-Generation Boron Drugs and Rational Translational Studies Driving the Revival of BNCT.

BNCT is a high-linear-energy transfer therapy that facilitates tumor-directed radiation delivery while largely sparing adjacent normal tissues through the biological targeting of boron compounds to tumor cells. Tumor-specific accumulation of boron with limited accretion in normal cells is the crux of successful BNCT delivery. Given this, developing novel boronated compounds with high selectivity, ease of delivery, and large boron payloads remains an area of active investigation. Furthermore, there is growing interest in exploring the immunogenic potential of BNCT. In this review, we discuss the basic radiobiological and physical aspects of BNCT, traditional and next-generation boron compounds, as well as translational studies exploring the clinical applicability of BNCT. Additionally, we delve into the immunomodulatory potential of BNCT in the era of novel boron agents and examine innovative avenues for exploiting the immunogenicity of BNCT to improve outcomes in difficult-to-treat malignancies.

Deep Learning-Based TEM Image Analysis for Fully Automated Detection of Gold Nanoparticles Internalized Within Tumor Cell.

Transmission electron microscopy (TEM) imaging can be used for detection/localization of gold nanoparticles (GNPs) within tumor cells. However, quantitative analysis of GNP-containing cellular TEM images typically relies on conventional/thresholding-based methods, which are manual, time-consuming, and prone to human errors. In this study, therefore, deep learning (DL)-based methods were developed for fully automated detection of GNPs from cellular TEM images. Several models of "you only look once (YOLO)" v5 were implemented, with a few adjustments to enhance the model's performance by applying the transfer learning approach, adjusting the size of the input image, and choosing the best optimization algorithm. Seventy-eight original (12,040 augmented) TEM images of GNP-laden tumor cells were used for model implementation and validation. A maximum F1 score (harmonic mean of the precision and recall) of 0.982 was achieved by the best-trained models, while mean average precision was 0.989 and 0.843 at 0.50 and 0.50-0.95 intersection over union threshold, respectively. These results suggested the developed DL-based approach was capable of precisely estimating the number/position of internalized GNPs from cellular TEM images. A novel DL-based TEM image analysis tool from this study will benefit research/development efforts on GNP-based cancer therapeutics, for example, by enabling the modeling of GNP-laden tumor cells using nanometer-resolution TEM images.

An ERK5-NRF2 Axis Mediates Senescence-Associated Stemness and Atherosclerosis.

BACKGROUND: ERK5 (extracellular signal-regulated kinase 5) is a dual kinase transcription factor containing an N-terminal kinase domain and a C-terminal transcriptional activation domain. Many ERK5 kinase inhibitors have been developed and tested to treat cancer and inflammatory diseases. However, recent data have raised questions about the role of the catalytic activity of ERK5 in proliferation and inflammation. We aimed to investigate how ERK5 reprograms myeloid cells to the proinflammatory senescent phenotype, subsequently leading to atherosclerosis. METHODS: A ERK5 S496A (dephosphorylation mimic) knock in (KI) mouse model was generated using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9), and atherosclerosis was characterized by hypercholesterolemia induction. The plaque phenotyping in homozygous ERK5 S496A KI and wild type (WT) mice was studied using imaging mass cytometry. Bone marrow-derived macrophages were isolated from hypercholesterolemic mice and characterized using RNA sequencing and functional in vitro approaches, including senescence, mitochondria reactive oxygen species, and inflammation assays, as well as by metabolic extracellular flux analysis. RESULTS: We show that atherosclerosis was inhibited in ERK5 S496A KI mice. Furthermore, ERK5 S496 phosphorylation mediates both senescence-associated secretory phenotype and senescence-associated stemness by upregulating AHR (aryl hydrocarbon receptor) in plaque and bone marrow-derived macrophages isolated from hypercholesterolemic mice. We also discovered that ERK5 S496 phosphorylation could induce NRF2 (NFE2-related factor 2) SUMOylation at a novel K518 site to inhibit NRF2 transcriptional activity without altering ERK5 catalytic activity and mediates oxidized LDL (low-density lipoprotein)-induced senescence-associated secretory phenotype. Specific ERK5 kinase inhibitors (AX15836 and XMD8-92) also inhibited ERK5 S496 phosphorylation, suggesting the involvement of ERK5 S496 phosphorylation in the anti-inflammatory effects of these ERK5 kinase inhibitors. CONCLUSIONS: We discovered a novel mechanism by which the macrophage ERK5-NRF2 axis develops a unique senescence-associated secretory phenotype/stemness phenotype by upregulating AHR to engender atherogenesis. The finding of senescence-associated stemness phenotype provides a molecular explanation to resolve the paradox of senescence in proliferative plaque by permitting myeloid cells to escape the senescence-induced cell cycle arrest during atherosclerosis formation.

Radiolabeled nanomaterial for cancer diagnostics and therapeutics: principles and concepts.

In the last three decades, radiopharmaceuticals have proven their effectiveness for cancer diagnosis and therapy. In parallel, the advances in nanotechnology have fueled a plethora of applications in biology and medicine. A convergence of these disciplines has emerged more recently with the advent of nanotechnology-aided radiopharmaceuticals. Capitalizing on the unique physical and functional properties of nanoparticles, radiolabeled nanomaterials or nano-radiopharmaceuticals have the potential to enhance imaging and therapy of human diseases. This article provides an overview of various radionuclides used in diagnostic, therapeutic, and theranostic applications, radionuclide production through different techniques, conventional radionuclide delivery systems, and advancements in the delivery systems for nanomaterials. The review also provides insights into fundamental concepts necessary to improve currently available radionuclide agents and formulate new nano-radiopharmaceuticals.

Pragmatic, Prospective Comparative Effectiveness Trial of Carbon Ion Therapy, Surgery, and Proton Therapy for the Management of Pelvic Sarcomas (Soft Tissue/Bone) Involving the Bone: The PROSPER Study Rationale and Design.

Surgical treatment of pelvic sarcoma involving the bone is the standard of care but is associated with several sequelae and reduced functional quality of life (QOL). Treatment with photon and proton radiotherapy is associated with relapse. Carbon ion radiotherapy (CIRT) may reduce both relapse rates and treatment sequelae. The PROSPER study is a tricontinental, nonrandomized, prospective, three-arm, pragmatic trial evaluating treatments of pelvic sarcoma involving the bone. Patients aged at least 15 years are eligible for inclusion. Participants must have an Eastern Cooperative Oncology Group Performance Status score of two or less, newly diagnosed disease, and histopathologic confirmation of pelvic chordoma, chondrosarcoma, osteosarcoma, Ewing sarcoma with bone involvement, rhabdomyosarcoma (RMS) with bone involvement, or non-RMS soft tissue sarcoma with bone involvement. Treatment arms include (1) CIRT (n = 30) delivered in Europe and Asia, (2) surgical treatment with or without adjuvant radiotherapy (n = 30), and (3) proton therapy (n = 30). Arms two and three will be conducted at Mayo Clinic campuses in Arizona, Florida, and Minnesota. The primary end point is to compare the 1-year change in functional QOL between CIRT and surgical treatment. Additional comparisons among the three arms will be made between treatment sequelae, local control, and other QOL measures.

Proton Therapy With Concurrent Chemotherapy for Thoracic Esophageal Cancer: Toxicity, Disease Control, and Survival Outcomes.

Purpose: When treating esophageal cancer with radiation therapy, it is critical to limit the dose to surrounding structures, such as the lung and/or heart, as much as possible. Proton radiation therapy allows a reduced radiation dose to both the heart and lungs, potentially reducing the risk of cardiopulmonary toxicity. Here, we report disease control, survival, and toxicity outcomes among patients with esophageal cancer treated with proton radiation therapy and concurrent chemotherapy (chemoradiation therapy; CRT) with or without surgery. Materials and Methods: We enrolled 17 patients with thoracic esophageal carcinoma on a prospective registry between 2010 and 2021. Patients received proton therapy to a median dose of 50.4-GyRBE (range, 50.4-64.8) in 1.8-Gy fractions.Acute and late toxicities were graded per the Common Terminology Criteria for Adverse Events, version 4.0 (US National Cancer Institute, Bethesda, Maryland). In addition, disease control, patterns of failure, and survival outcomes were collected. Results: Nine patients received preoperative CRT, and 8 received definitive CRT. Overall, 88% of patients had adenocarcinoma, and 12% had squamous cell carcinoma. With a median follow-up of 2.1 years (range, 0.5-9.4), the 3-year local progression-free, disease-free, and overall survival rates were 85%, 66%, and 55%, respectively. Two patients (1 with adenocarcinoma and 1 with squamous cell carcinoma) recurred at the primary site after refusing surgery after a complete clinical response to CRT. The most common acute nonhematologic and hematologic toxicities, respectively, were grades 1 to 3 esophagitis and grades 1 to 4 leukopenia, both affecting 82% of patients. No acute cardiopulmonary toxicities were observed in the absence of surgical resection. Reagarding surgical complications, 3 postoperative cardiopulmonary complications occurred as follows: 1 grade 1 pleural effusion, 1 grade 3 pleural effusion, and 1 grade 2 anastomotic leak. Two severe late CRT toxicities occurred: 1 grade 5 tracheoesophageal fistula and 1 grade 3 esophageal stenosis requiring a feeding tube. Conclusion: Proton radiation therapy is a safe, effective treatment for esophageal cancer with increasing evidence supporting its role in reducing cardiopulmonary toxicity.

Radiotherapy reimagined: Integrating nanomedicines into radiotherapy clinical trials.

Radioenhancing nanoparticles (NPs) are being evaluated in ongoing clinical trials for various cancers including head and neck, lung, esophagus, pancreas, prostate, and soft tissue sarcoma. Supported by decades of preclinical investigation and recent randomized trial data establishing clinical activity, these agents are poised to influence future multimodality treatment paradigms involving radiotherapy. Although the physical interactions between NPs and ionizing radiation are well characterized, less is known about how these agents modify the tumor microenvironment, particularly regarding tumor immunogenicity. In this review, we describe the key multidisciplinary considerations related to radiation, surgery, immunology, and pathology for designing radioenhancing NP clinical trials. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Lipid-Nanoparticle-Mediated Delivery of Docetaxel Prodrug for Exploiting Full Potential of Gold Nanoparticles in the Treatment of Pancreatic Cancer.

Current chemoradiation therapy suffers from normal tissue toxicity. Thus, we are proposing incorporating gold nanoparticles (GNPs) and docetaxel (DTX), as they have shown very promising synergetic radiosensitization effects. Here, we explored the effect of a DTX prodrug encapsulated in lipid nanoparticles (LNPDTX-P) on GNP uptake in pancreatic cancer models in vitro and in vivo. For the in vitro experiment, a pancreatic cancer cell line, MIA PaCa-2, was cultured and dosed with 1 nM GNPs and 45 nM free DTX or an equivalent dose of LNPDTX-P. For the in vivo experiment, MIA PaCa-2 cells were implanted subcutaneously in NRG mice, and the mice were dosed with 2 mg/kg of GNPs and 6 mg/kg of DTX or an equivalent dose of LNPDTX-P. The results show that LNPDTX-P-treated tumour samples had double the amount GNPs compared to control samples, both in vitro and in vivo. The results are very promising, as LNPDTX-P have superior targeting of tumour tissues compared to free DTX due to their nanosize and their ability to be functionalized. Because of their minimal toxicity to normal tissues, both GNPs and LNPDTX-P could be ideal radiosensitization candidates in radiotherapy and would produce very promising synergistic therapeutic outcomes.

Lymphocyte sparing normal tissue effects in the clinic (LymphoTEC): A systematic review of dose constraint considerations to mitigate radiation-related lymphopenia in the era of immunotherapy.

BACKGROUND: Radiation-related lymphopenia has been associated with suboptimal tumor control rates leading to inferior survival outcomes. To date, no standardized dose constraints are available to limit radiation dose to resident and circulating lymphocyte populations. We undertook this systemic review of the literature to provide a synopsis of the dosimetric predictors of radiation-related lymphopenia in solid malignancies. METHODOLOGY: A systematic literature review of PubMed (National Institutes of Health), Cochrane Central (Cochrane collaboration), and Google Scholar was conducted with the following keywords: "radiation", "lymphopenia", "cancer", "dosimetric predictors" with an inclusion deadline of May 31, 2022. Studies that met prespecified inclusion criteria were designated either Good, Fair, or Poor Quality based on the Newcastle-Ottawa quality assessment. The dosimetric parameters derived from Good Quality studies were tabulated as LymphoTEC dose constraints. Dosimetric parameters derived from Fair and Poor-quality studies were grouped as optional. RESULTS: An initial systematic search of the literature yielded 1,632 articles. After screening, a total of 48 studies met inclusion criteria and were divided into the following categories: central nervous system (CNS, 6), thoracic (11), gastrointestinal (26), gynecologic (2), head and neck, breast, and genitourinary (one each) cancers. Lung mean dose, heart mean dose, brain V25, spleen mean dose, estimated dose to immune cells, and bone marrow V10 were among the strongest predictors for severe lymphopenia related to radiotherapy. CONCLUSION: Optimizing the delivery of radiation therapy to limit dose to lymphocyte-rich structures may curb the negative oncologic impact of lymphocyte depletion. The dose constraints described herein may be considered for prospective validation and future use in clinical trials to limit risk of radiation-related lymphopenia and possibly improve cancer-associated outcomes.

Uncloaking cell-impermeant gold nanorods via tumor microenvironmental cathepsin B facilitates cancer cell penetration and potent radiosensitization.

Major impediments to conveyance of intravenously administered drugs to tumors are biofouling, opsonization, and rapid clearance from the circulation by macrophages and reticuloendothelial phagocytes. Cloaking nanoparticles with stealth epilayers partly overcomes these hurdles but it also foils interactions with tumor cells. Here, we describe the synthesis, characterization, and validation of smart gold nanorods (GNRs) that spontaneously transform from inert passengers in the blood stream to active cell-penetrating nanoparticles within tumors to potently sensitize tumors to radiation therapy. Intrinsically cationic and cell-penetrating GNRs were shielded from phagocytosis with a cloaking polyethylene glycol epilayer containing an intervening cleavable peptide. In the absence of an external trigger, this epilayer is clipped off by the tumor microenvironmental protease, cathepsin B, in colorectal cancers to uncloak and expose the free-circulating native unPEGylated GNR that is readily internalized by cancer cells and turn into immovable small clusters of GNRs. Selective uncloaking of GNRs in the tumor reduced off-target toxicity confirmed by hematologic, biochemical, and histopathological analysis of blood, serum, and normal organs, respectively. Subsequent irradiation led to significant tumor growth delay and improved survival of mice. By addressing multiple barriers to efficient transport and cellular internalization of nanoparticles, our results demonstrate that clinically meaningful radiosensitization can be achieved with rationally designed GNRs.

Pancreatic tumor microenvironmental acidosis and hypoxia transform gold nanorods into cell-penetrant particles for potent radiosensitization.

Coating nanoparticles with stealth epilayers increases circulation time by evading opsonization, macrophage phagocytosis, and reticuloendothelial sequestration. However, this also reduces internalization by cancer cells upon reaching the tumor. We designed gold nanorods (GNRs) with an epilayer that retains stealth properties in circulation but transforms spontaneously in the acidotic tumor microenvironment to a cell-penetrating particle. We used a customized stoichiometric ratio of l-glutamic acid and l-lysine within an amphiphilic polymer of poly(l-glutamic acid-co-l-lysine), or P(Glu-co-Lys), to effect this transformation in acidotic environments. P(Glu-co-Lys)-GNRs were internalized by cancer cells to facilitate potent in vitro radiosensitization. When administered intravenously in mice, they accumulate in the periphery and core of tumors without any signs of serum biochemical or hematological alterations, normal organ histopathological abnormalities, or overt deterioration in animal health. Furthermore, P(Glu-co-Lys)-GNRs penetrated the tumor microenvironment to accumulate in the hypoxic cores of tumors to potently radiosensitize heterotopic and orthotopic pancreatic cancers in vivo.

Enhancing nanoparticle accumulation in two dimensional, three dimensional, and xenograft mouse cancer cell models in the presence of docetaxel.

Recent clinical trials show docetaxel (DTX), given in conjunction with radiation therapy (RT) and androgen suppression, improves survival in high-risk prostate cancer. Addition of gold nanoparticles (GNPs) to this current DTX/RT protocol is expected to further improve therapeutic benefits remarkably. However, the foundation for the triple combination of RT, DTX, and GNPs must be elucidated to ensure quicker facilitation to the clinic. In this study, we explored the use of low concentrations of DTX combined with GNPs in two prostate cancer cell lines in a two-dimensional monolayer, a three-dimensional spheroid, and a mouse xenograft model. When used together, DTX and GNPs induced a nearly identical relative increase in uptake of gold in both the spheroid model and the mouse xenograft, which saw a 130% and 126% increase respectively after 24 h, showcasing the benefit of using spheroids as an in vitro model to better optimize in vivo experiments. Further, the benefits of using low concentrations of DTX combined with GNPs extended for over 72 h, allowing for less frequency in dosing when translating to the clinic. Overall, these results highlight the benefits of using DTX combined with GNPs and lays the groundwork for the translation of the triple combination of RT, GNPs, and DTX to the clinic.

Nab-Paclitaxel, Capecitabine, and Radiation Therapy After Induction Chemotherapy in Treating Patients With Locally Advanced and Borderline Resectable Pancreatic Cancer: Phase 1 Trial and Imaging-based Biomarker Validation.

PURPOSE: Effective consolidative chemoradiation (CRT) regimens are lacking. In this phase 1 trial, we evaluated the safety and efficacy of nab-paclitaxel, capecitabine, and radiation therapy after induction chemotherapy in patients with locally advanced and borderline-resectable pancreatic cancer (LAPC and BRPC). Also, we evaluated a computed tomography (CT)-based biomarker of response. METHODS AND MATERIALS: Eligible patients had pathologically confirmed pancreatic ductal adenocarcinoma, underwent computed tomography-imaging, received a diagnosis of LAPC or BRPC, and received induction chemotherapy. Standard 3 + 3 study design was used, with 3 escalating nab-paclitaxel dose levels (50, 75, and 100 mg/m2) with concurrent capecitabine and RT in cohort sizes of 3 starting at the lowest dose. Dose limiting toxicity was defined as grade 3 or higher toxicity. Patients were restaged 4 to 6 weeks post-CRT completion, and surgical resection was offered to those with stable/responsive disease. We scored the tumor interface response (IR) postchemotherapy and post-CRT into type I (remained/became more defined) and type II (became less defined). Overall survival (OS) and progression-free survival (PFS) from time of CRT were estimated using Kaplan-Meier method. P ≤ .05 was considered significant. RESULTS: Twenty-three patients started and finished on protocol (LAPC = 14, BRPC = 9). No grade 3 and 4 toxicities were reported in level 1 (n = 3) or level 2 (n = 3) initial groups. Two patients in the initial level 3 group developed dose limiting toxicity, establishing level 2 dose as the maximal tolerated dose. Level 2 group was expanded for additional 15 patients (for a total of 23 on trial), 5 of whom developed grade 3 toxicities. Seven patients underwent surgical resection. Median OS and PFS were 21.2 and 8.1 months, respectively. Type I IR was associated with better OS (P = .004) and PFS (P = .03) compared with type II IR. CONCLUSIONS: We established the maximum tolerated dose for nab-paclitaxel in a consolidative CRT regimen for pancreatic ductal adenocarcinoma. Preliminary efficacy results warrant phase 2 trial evaluation. IR may be used for personalized treatment.

Identification of Synergistic Drug Combinations to Target KRAS-Driven Chemoradioresistant Cancers Utilizing Tumoroid Models of Colorectal Adenocarcinoma and Recurrent Glioblastoma.

Treatment resistance is observed in all advanced cancers. Colorectal cancer (CRC) presenting as colorectal adenocarcinoma (COAD) is the second leading cause of cancer deaths worldwide. Multimodality treatment includes surgery, chemotherapy, and targeted therapies with selective utilization of immunotherapy and radiation therapy. Despite the early success of anti-epidermal growth factor receptor (anti-EGFR) therapy, treatment resistance is common and often driven by mutations in APC, KRAS, RAF, and PI3K/mTOR and positive feedback between activated KRAS and WNT effectors. Challenges in the direct targeting of WNT regulators and KRAS have caused alternative actionable targets to gain recent attention. Utilizing an unbiased drug screen, we identified combinatorial targeting of DDR1/BCR-ABL signaling axis with small-molecule inhibitors of EGFR-ERBB2 to be potentially cytotoxic against multicellular spheroids obtained from WNT-activated and KRAS-mutant COAD lines (HCT116, DLD1, and SW480) independent of their KRAS mutation type. Based on the data-driven approach using available patient datasets (The Cancer Genome Atlas (TCGA)), we constructed transcriptomic correlations between gene DDR1, with an expression of genes for EGFR, ERBB2-4, mitogen-activated protein kinase (MAPK) pathway intermediates, BCR, and ABL and genes for cancer stem cell reactivation, cell polarity, and adhesion; we identified a positive association of DDR1 with EGFR, ERBB2, BRAF, SOX9, and VANGL2 in Pan-Cancer. The evaluation of the pathway network using the STRING database and Pathway Commons database revealed DDR1 protein to relay its signaling via adaptor proteins (SHC1, GRB2, and SOS1) and BCR axis to contribute to the KRAS-PI3K-AKT signaling cascade, which was confirmed by Western blotting. We further confirmed the cytotoxic potential of our lead combination involving EGFR/ERBB2 inhibitor (lapatinib) with DDR1/BCR-ABL inhibitor (nilotinib) in radioresistant spheroids of HCT116 (COAD) and, in an additional devastating primary cancer model, glioblastoma (GBM). GBMs overexpress DDR1 and share some common genomic features with COAD like EGFR amplification and WNT activation. Moreover, genetic alterations in genes like NF1 make GBMs have an intrinsically high KRAS activity. We show the combination of nilotinib plus lapatinib to exhibit more potent cytotoxic efficacy than either of the drugs administered alone in tumoroids of patient-derived recurrent GBMs. Collectively, our findings suggest that combinatorial targeting of DDR1/BCR-ABL with EGFR-ERBB2 signaling may offer a therapeutic strategy against stem-like KRAS-driven chemoradioresistant tumors of COAD and GBM, widening the window for its applications in mainstream cancer therapeutics.

ATR-mediated CD47 and PD-L1 up-regulation restricts radiotherapy-induced immune priming and abscopal responses in colorectal cancer.

Radiotherapy (RT) of colorectal cancer (CRC) can prime adaptive immunity against tumor-associated antigen (TAA)-expressing CRC cells systemically. However, abscopal tumor remissions are extremely rare, and the postirradiation immune escape mechanisms in CRC remain elusive. Here, we found that irradiated CRC cells used ATR-mediated DNA repair signaling pathway to up-regulate both CD47 and PD-L1, which through engagement of SIRPα and PD-1, respectively, prevented phagocytosis by antigen-presenting cells and thereby limited TAA cross-presentation and innate immune activation. This postirradiation CD47 and PD-L1 up-regulation was observed across various human solid tumor cells. Concordantly, rectal cancer patients with poor responses to neoadjuvant RT exhibited significantly elevated postirradiation CD47 levels. The combination of RT, anti-SIRPα, and anti-PD-1 reversed adaptive immune resistance and drove efficient TAA cross-presentation, resulting in robust TAA-specific CD8 T cell priming, functional activation of T effectors, and increased T cell clonality and clonal diversity. We observed significantly higher complete response rates to RT/anti-SIRPα/anti-PD-1 in both irradiated and abscopal tumors and prolonged survival in three distinct murine CRC models, including a cecal orthotopic model. The efficacy of triple combination therapy was STING dependent as knockout animals lost most benefit of adding anti-SIRPα and anti-PD-1 to RT. Despite activation across the myeloid stroma, the enhanced dendritic cell function accounts for most improvements in CD8 T cell priming. These data suggest ATR-mediated CD47 and PD-L1 up-regulation as a key mechanism restraining radiation-induced immune priming. RT combined with SIRPα and PD-1 blockade promotes robust antitumor immune priming, leading to systemic tumor regressions.