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Photoimmunotherapy (PIT), carried out using an Ab conjugated to the near infrared dye IRDye700DX, is achieving significant success in target-specific elimination of cells. Fibroblast activation protein alpha (FAP-α) is an important target in cancer because of its expression by cancer-associated fibroblasts (CAFs) as well as by some cancer cells. Cancer-associated fibroblasts that express FAP-α have protumorigenic and immune suppressive functions. Using immunohistochemistry of human breast cancer tissue microarrays, we identified an increase of FAP-α

Approximately 20% of all spinal cord injuries (SCI) occur in persons aged 65 years or older. Longitudinal, population-based studies showed that SCI is a risk factor for dementia. However, little research has addressed the potential mechanisms of SCI-mediated neurological impairment in the elderly. We compared young adult and aged C57BL/6 male mice subjected to contusion SCI, using a battery of neurobehavioral tests. Locomotor function showed greater impairment in aged mice, which was correlated with reduced, spared spinal cord white matter and increased lesion volume. At 2 months post-injury, aged mice displayed worse performance in cognitive and depressive-like behavioral tests. Transcriptomic analysis identified activated microglia and dysregulated autophagy as the most significantly altered pathways by both age and injury. Flow cytometry demonstrated increased myeloid and lymphocyte infiltration at both the injury site and brain of aged mice. SCI in aged mice was associated with altered microglial function and dysregulated autophagy involving both microglia and brain neurons. Altered plasma extracellular vesicles (EVs) responses were found in aged mice after acute SCI. EV-microRNA cargos were also significantly altered by aging and injury, which were associated with neuroinflammation and autophagy dysfunction. In cultured microglia, astrocytes, and neurons, plasma EVs from aged SCI mice, at a lower concentration comparable to those of young adult SCI mice, induced the secretion of pro-inflammatory cytokines CXCL2 and IL-6, and increased caspase3 expression. Together, these findings suggest that age alters the EVs pro-inflammatory response to SCI, potentially contributing to worse neuropathological and functional outcomes.

Extracellular vesicles (EVs) have emerged as important mediators in cell–cell communication; however, their relevance in pulmonary hypertension (PH) secondary to human immunodeficiency virus (HIV) infection is yet to be explored. Considering that circulating monocytes are the source of the increased number of perivascular macrophages surrounding the remodeled vessels in PH, this study aimed to identify the role of circulating small EVs and EVs released by HIV-infected human monocyte–derived macrophages in the development of PH. We report significantly higher numbers of plasma-derived EVs carrying higher levels of TGF-β1 (transforming growth factor-β1) in HIV-positive individuals with PH compared with individuals without PH. Importantly, levels of these TGF-β1–loaded, plasma-derived EVs correlated with pulmonary arterial systolic pressures and CD4 counts but did not correlate with the Dl (CO) or viral load. Correspondingly, enhanced TGF-β1–dependent pulmonary endothelial injury and smooth muscle hyperplasia were observed. HIV-1 infection of monocyte-derived macrophages in the presence of cocaine resulted in an increased number of TGF-β1–high EVs, and intravenous injection of these EVs in rats led to increased right ventricle systolic pressure accompanied by myocardial injury and increased levels of serum ET-1 (endothelin-1), TNF-α, and cardiac troponin-I. Conversely, pretreatment of rats with TGF-β receptor 1 inhibitor prevented these EV-mediated changes. Findings define the ability of macrophage-derived small EVs to cause pulmonary vascular modeling and PH via modulation of TGF-β signaling and suggest clinical implications of circulating TGF-β–high EVs as a potential biomarker of HIV-associated PH.

Small interfering RNA (siRNA) is ideal for gene silencing through a sequence-specific RNA interference process. The redundancy and complexity of molecular pathways in cancer create a need for multiplexed targeting that can be achieved with multiplexed siRNA delivery. Here, we delivered multiplexed siRNA with a PSMA-targeted biocompatible dextran nanocarrier to downregulate CD46 and PD-L1 in PSMA expressing prostate cancer cells. The selected gene targets, PD-L1 and CD46, play important roles in the escape of cancer cells from immune surveillance. PSMA, abundantly expressed by prostate cancer cells, allowed the prostate cancer-specific delivery of the nanocarrier. The nanocarrier was modified with acid cleavable acetal bonds for a rapid release of siRNA. Cell imaging and flow cytometry studies confirmed the PSMA-specific delivery of CD46 and PD-L1 siRNA to high PSMA expressing PC-3 PIP cells. Immunoblot, qRT-PCR and flow cytometry methods confirmed the downregulation of CD46 and PD-L1 following treatment with multiplexed siRNA.

SARS-CoV-2, the causative agent of COVID-19 disease has resulted in the death of millions worldwide since the beginning of the pandemic in December 2019. While much progress has been made to understand acute manifestations of SARS-CoV-2 infection, less is known about post-acute sequelae of COVID-19 (PASC). We investigated the levels of circulating SARS-CoV-2 components, Spike protein and viral RNA, in patients hospitalized with acute COVID-19 and in patients with and without PASC. In hospitalized patients with acute COVID-19 (n=116), we observed a positive correlation of Spike protein with D-dimer, length of hospitalization, and peak WHO score while viral RNA correlated with a tissue injury marker, lactate dehydrogenase (LDH). When comparing patients with post-COVID symptoms (n=33) and patients without (n=14), we found that Spike protein and viral RNA were more likely to be present in patients with PASC and in some cases at higher levels compared to acute COVID-19 patients. We also observed that the percent positivity of circulating viral RNA increased in the PASC positive individuals compared to acute COVID-19 group while Spike protein positivity remained the same. Additionally, we report that part of the circulating Spike protein is linked to extracellular vesicles without any presence of viral RNA in these vesicles. In conclusion, our findings suggest that Spike protein and/or viral RNA fragments persist in the recovered COVID-19 patients with PASC, regardless of their presence or absence during the acute COVID-19 phase. These results may help in understanding the reason(s) for why patients experience PASC symptoms and may offer potential therapeutic targets.

Highlights • Developed a hypoxia theranostic imaging strategy to eliminate hypoxic cells. • Hypoxic cell elimination resulted in fewer cancer associated fibroblasts (CAFs) • Collagen 1 fiber patterns were altered with hypoxic cell elimination. • cDNA nanoparticles with HRE driven prodrug enzyme expression can target hypoxia., Hypoxia is frequently observed in human prostate cancer, and is associated with chemoresistance, radioresistance, metastasis, and castrate-resistance. Our purpose in these studies was to perform hypoxia theranostics by combining in vivo hypoxia imaging and hypoxic cancer cell targeting in a human prostate cancer xenograft. This was achieved by engineering PC3 human prostate cancer cells to express luciferase as well as a prodrug enzyme, yeast cytosine deaminase, under control of hypoxic response elements (HREs). Cancer cells display an adaptive response to hypoxia through the activation of several genes mediated by the binding of hypoxia inducible factors (HIFs) to HRE in the promoter region of target gene that results in their increased transcription. HIFs promote key steps in tumorigenesis, including angiogenesis, metabolism, proliferation, metastasis, and differentiation. HRE-driven luciferase expression allowed us to detect hypoxia in vivo to time the administration of the nontoxic prodrug 5-fluorocytosine that was converted by yeast cytosine deaminase, expressed under HRE regulation, to the chemotherapy agent 5-fluorouracil to target hypoxic cells. Conversion of 5-fluorocytosine to 5-fluorouracil was detected in vivo by 19F magnetic resonance spectroscopy. Morphological and immunohistochemical staining and molecular analyses were performed to characterize tumor microenvironment changes in cancer-associated fibroblasts, cell viability, collagen 1 fiber patterns, and HIF-1α. These studies expand our understanding of the effects of eliminating hypoxic cancer cells on the tumor microenvironment and in reducing stromal cell populations such as cancer-associated fibroblasts.

Background Cachexia is a major cause of morbidity in pancreatic ductal adenocarcinoma (PDAC) patients. Our purpose was to understand the impact of PDAC‐induced cachexia on brain metabolism in PDAC xenograft studies, to gain new insights into the causes of cachexia‐induced morbidity. Changes in mouse and human plasma metabolites were characterized to identify underlying causes of brain metabolic changes. Methods We quantified metabolites, detected with high‐resolution 1H magnetic resonance spectroscopy, in the brain and plasma of normal mice (n = 10) and mice bearing cachexia (n = 10) or non‐cachexia (n = 9) inducing PDAC xenografts as well as in human plasma obtained from normal individuals (n = 24) and from individuals with benign pancreatic disease (n = 20) and PDAC (n = 20). Statistical significance was defined as a P value ≤0.05. Results The brain metabolic signature of cachexia‐inducing PDAC was characterized by a significant depletion of choline of −27% and −21% as well as increases of glutamine of 13% and 9% and formate of 21% and 14%, relative to normal controls and non‐cachectic tumour‐bearing mice, respectively. Good to moderate correlations with percent weight change were found for choline (r = 0.70), glutamine (r = −0.58), and formate (r = −0.43). Significant choline depletion of −38% and −30%, relative to normal controls and non‐cachectic tumour‐bearing mice, respectively, detected in the plasma of cachectic mice likely contributed to decreased brain choline in cachectic mice. Similarly, relative to normal controls and patients with benign disease, choline levels in human plasma samples of PDAC patients were significantly lower by −12% and −20% respectively. A comparison of plasma metabolites from PDAC patients with and without weight loss identified significant changes in glutamine metabolism. Conclusions Disturbances in metabolites of the choline/cholinergic and glutamine/glutamate/glutamatergic neurotransmitter pathways may contribute to morbidity. Metabolic normalization may provide strategies to reduce morbidity. The human plasma metabolite changes observed may lead to the development of companion diagnostic markers to detect PDAC and PDAC‐induced cachexia.

Cancer stem cells (CSCs) have the ability to self-renew and induce drug resistance and recurrence in colorectal cancer (CRC). As current chemotherapy doesn’t eliminate CSCs completely, there is a need to identify novel agents to target them. We investigated the effects of cucurbitacin B (C-B) or I (C-I), a natural compound that exists in edible plants (bitter melons, cucumbers, pumpkins and zucchini), against CRC. C-B or C-I inhibited proliferation, clonogenicity, induced G2/M cell-cycle arrest and caspase-mediated-apoptosis of CRC cells. C-B or C-I suppressed colonosphere formation and inhibited expression of CD44, DCLK1 and LGR5. These compounds inhibited notch signaling by reducing the expression of Notch 1–4 receptors, their ligands (Jagged 1-2, DLL1,3,4), γ-secretase complex proteins (Presenilin 1, Nicastrin), and downstream target Hes-1. Molecular docking showed that C-B or C-I binds to the ankyrin domain of Notch receptor, which was confirmed using the cellular thermal shift assay. Finally, C-B or C-I inhibited tumor xenograft growth in nude mice and decreased the expression of CSC-markers and notch signaling proteins in tumor tissues. Together, our study suggests that C-B and C-I inhibit colon cancer growth by inhibiting Notch signaling pathway.

Photoimmunotherapy (PIT) using an antibody conjugated to a near infrared dye IR700 is achieving significant success in target-specific elimination of cells. Fibroblast activation protein alpha (FAP-α) is an important target in cancer because of its expression by cancer associated fibroblasts (CAFs) as well as by some cancer cells. CAFs that express FAP-α have protumorigenic and immune suppressive functions. Using immunohistochemistry of human breast cancer tissue microarrays, we identified an increase of FAP-α+ CAFs in invasive breast cancer tissue compared to adjacent normal tissue. We found FAP-α expression increased in fibroblasts co-cultured with cancer cells. In proof-of-principle studies, we engineered human FAP-α overexpressing MDA-MB-231 and HT-1080 cancer cells and murine FAP-α overexpressing NIH-3T3 fibroblasts to evaluate several anti-FAP-α antibodies and selected AF3715 based on its high binding-affinity with both human and mouse FAP-α. After conjugation of AF3715 with the phthalocyanine dye IR700, the resultant antibody conjugate, FAP-α-IR700, was evaluated in cells and tumors for its specificity and effectiveness in eliminating FAP-α expressing cell populations with PIT. FAP-α-IR700-PIT resulted in effective FAP-α-specific cell killing in the engineered cancer cells and in two patient-derived CAFs in a dose-dependent manner. Following an intravenous injection, FAP-α-IR700 retention was three-fold higher than IgG-IR700 in FAP-α overexpressing tumors, and two-fold higher compared to wild-type tumors. FAP-α-IR700-PIT resulted in significant growth inhibition of tumors derived from FAP-α overexpressing human cancer cells. A reduction of endogenous FAP-α+ murine CAFs was identified at 7 days after FAP-α-IR700-PIT. FAP-α-targeted NIR-PIT presents a promising strategy to eliminate FAP-α+ CAFs.

Hypoxia in cancers has evoked significant interest since 1955 when Thomlinson and Gray postulated the presence of hypoxia in human lung cancers, based on the observation of necrosis occurring at the diffusion limit of oxygen from the nearest blood vessel, and identified the implication of these observations for radiation therapy. Coupled with discoveries in 1953 by Gray and others that anoxic cells were resistant to radiation damage, these observations have led to an entire field of research focused on exploiting oxygenation and hypoxia to improve the outcome of radiation therapy. Almost 65 years later, tumor heterogeneity of nearly every parameter measured including tumor oxygenation, and the dynamic landscape of cancers and their microenvironments are clearly evident, providing a strong rationale for cancer personalized medicine. Since hypoxia is a major cause of extracellular acidosis in tumors, here, we have focused on the applications of imaging to understand the effects of hypoxia in tumors and to target hypoxia in theranostic strategies. Molecular and functional imaging have critically important roles to play in personalized medicine through the detection of hypoxia, both spatially and temporally, and by providing new understanding of the role of hypoxia in cancer aggressiveness. With the discovery of the hypoxia-inducible factor (HIF), the intervening years have also seen significant progress in understanding the transcriptional regulation of hypoxia-induced genes. These advances have provided the ability to silence HIF and understand the associated molecular and functional consequences to expand our understanding of hypoxia and its role in cancer aggressiveness. Most recently, the development of hypoxia-based theranostic strategies that combine detection and therapy are further establishing imaging-based treatment strategies for precision medicine of cancer.

Metastatic dissemination continues to be a major cause of prostate cancer (PCa) mortality, creating a compelling need to understand factors that play a role in the metastatic cascade. Since hypoxia plays an important role in PCa aggressiveness, we characterized patterns of hypoxia in the primary tumor and metastatic environments of a human PCa xenograft. We previously developed and characterized an imaging strategy based on the hypoxia response element (HRE)–driven expression of long-lived enhanced green fluorescent protein (EGFP) and short-lived luciferase (luc) fused to the oxygen-dependent degradation domain in human PCa PC-3 cells. Both reporter proteins were placed under the transcriptional control of a five–tandem repeat HRE sequence. PC-3 cells also constitutively expressed the tdTomato red fluorescent protein, allowing cancer cell detection in vivo. This “timer” strategy can provide information on the temporal evolution of HIF activity and hypoxia in tumors. Here, for the first time, we performed in vivo and ex vivo imaging of this dual HIF reporter system in PC-3 metastatic tumors implanted orthotopically in the prostate and PC-3 nonmetastatic tumors implanted subcutaneously. We observed distinct patterns of EGFP and luc expression in subcutaneous and orthotopic tumors, and in metastatic nodules, that provide new insights into the presence of hypoxia at primary and metastatic tumor sites, and of the role of hypoxia in metastasis.

Biomimetic nanoparticles (NPs) combine the flexibility and reproducibility of synthetic materials with the functionality of biological materials. Here, we developed and characterized biomimetic poly (lactic-co-glycolic acid) (PLGA) NPs coated with human cancer cell membrane fractions (CCMFs) to form CCMF coated PLGA (CCMF-PLGA) NPs. We evaluated the ability of these CCMF-PLGA NPs to disrupt cancer cell-stromal cell interactions, and to induce an immune response. Western blot analysis verified the plasma membrane purity of CCMFs. Confocal fluorescence microscopy and flow cytometry confirmed the presence of intact membrane-associated proteins including CXCR4 and CD44 following membrane derivation and coating. CCMFs and CCMF-PLGA NPs were capable of inhibiting cancer cell migration towards human mammary fibroblasts. Intravenous injection of CCMF-PLGA NPs significantly reduced experimental metastasis in vivo. Following immunization of Balb/c mice, near-infrared fluorescence imaging confirmed the migration of NPs to proximal draining lymph nodes. A higher percentage of CD8(+) and CD4(+) cytotoxic T-lymphocyte populations were observed in spleens and lymph nodes of CCMF-PLGA NP-immunized mice. Splenocytes isolated from CCMF-PLGA NP-immunized mice had the highest number of interferon gamma producing L cells as detected by the ELISpot assay. CCMF-PLGA NPs hold promise for disrupting cancer cell-stromal cell interactions, and for priming the immune system in cancer immunotherapy.

Additional file 1: Supplementary Figure 1. Correlation between the mean expression of Chk-α and PD-L1 in different cancer cell lines when treated with siRNA for 48h corresponding to Figure 1. Plot showing a correlation between mRNA expression level of Chk-α and PD-L1 obtained by RT-PCR of (A) MDA-MB-231, (B) SUM 149, (C) Pa09C and (D) Pa20C cells. Statistical analysis using Pearson’s correlation coefficient showed a significant correlation with P≤0.001 for all except Pa20C cells. Supplementary Figure 2. Representative flow cytometry histograms for MDA-MB-231 cells treated with siRNA corresponding to Figure 2. Representative flow cytometry histograms showing signals from control IgG-APC (blue) and anti-PD-L1-APC (red) antibodies in MDA-MB-231 cells: untreated (A), transfected with 100 nM scrambled siRNA (B), transfected with 100 nM luciferase siRNA (C), transfected with 100 nM Chk-siRNA (D), transfected with 100 nM PD-L1 siRNA (E) and transfected with a mixture of 50 nM PD-L1 and 50 nM Chk-α siRNA (Chk-α + PD-L1) (F). Supplementary Figure 3. Correlation between the expression of Chk-α and PD-L1 in primary tumor tissue among different human cancers corresponding to Figure 7. Individual levels of Chk-α and PD-L1 measured in different tumor types showed a statistically significant correlation (P< 0.001, r=-0.358) according to Spearman's correlation coefficient. Supplementary Figure 4. Comparison between Chk-α and PD-L1 in primary tumors with the highest and lowest values of these genes corresponding to Figure 7. We ranged primary tumors from the TCGA TARGET GTEx database according to their mRNA levels for Chk-α and PD-L1. We selected those samples, irrespective of the tumor type, based on the 10% highest and 10% lowest values for (A) Chk-α and (B) PD-L1. Supplementary Table 1. Mean values of water-soluble metabolite concentrations in MDA-MB-231 cells corresponding to Figure 3. Values were generated from the quantitative analysis of high-resolution 1H MR spectra obtained at 48h from the aqueous phase of MDA-MB-231 cells that were: untreated, transfected with 100 nM luciferase siRNA (Luciferase), transfected with 100 nM Chk-α siRNA (Chk-α), transfected with 100 nM PD-L1 #1 siRNA (PD-L1) and transfected with a mixture of 50 nM PD-L1 and 50 nM Chk-α siRNA (Chk-α + PD-L1). Values represent Mean (mM /cell) ± SEM from 3-6 independent experiments. GPC: glycerophosphocholine, PC: phosphocholine, Cho: choline, GSH: glutathione, GSSG: oxidized glutathione, MTA: S-methyl-5′-thioadenosine. Supplementary Table 2. Mean values of lipid metabolites in MDA-MB-231 cells corresponding to Figure 4. Values were generated from the quantitative analysis of high-resolution 1H MR spectra obtained at 48h from the lipid phase of MDA-MB-231 that were: untreated (control), transfected with 100 nM luciferase siRNA (Luciferase), transfected with 100 nM Chk-α siRNA (Chk-α), transfected with 100 nM PD-L1 #1 siRNA (PD-L1) and transfected with a mixture of 50 nM PD-L1 and 50 nM Chk-α siRNA (Chk-α + PD-L1). Values represent Mean (a.u.) ± SEM obtained from 3-6 independent experiments. Lipids (-CH3): methyl groups of fatty acids, Lipids (-CH2-): methylene groups of fatty acids, OOC-CH2: methylene groups at the α position of the carboxylic function, OOC-CH2-CH2: methylene groups at the β position of the carboxylic function, ARA: arachidonic acid, EPA: eicosapentaenoic acid, PtdEA: phosphatidylethanolamine, PtdCholine: phosphatidylcholine, (CH=CH-CH2-CH=CH)n: diallylic methylene protons, CH=CH-CH2: methylene groups at the α position of a double bond, CH=CH: fatty acid double bonds. Supplementary Table 3. Mean values for Chk-α and PD-L1 expression for 32 different tumor types corresponding to Figure 7. Values were extracted from the TCGA public database and expressed as the Mean ± SEM. The number of tumor samples for each tumor type available in the TCGA data base are also presented. Supplementary Table 4. Correlation coefficients between PD-L1 and Chk-α expression in different tumor types corresponding to Figure 7. Correlation coefficients were calculated used the c-bioportal, and by selecting mRNA Expression Z-scores (RNA Seq V2 RSEM) with a z-score threshold of ±2.0. Statistically significant correlations (p

Introduction: Our ongoing studies are focused on characterizing metabolic changes induced in the organs of mice with cachexia-inducing Pa04C human pancreatic cancer xenografts. Because pancreatic cancer cells are glutamine dependent [1], we downregulated the glutamine transporter SLC1A5 in Pa04C cells to determine if metabolic changes induced in the spleen and pancreas by Pa04C tumors were normalized when SLC1A5 was downregulated in these tumors. Metabolic patterns were characterized using high-resolution quantitative 1H magnetic resonance spectroscopy (MRS) of spleen and pancreas tissue obtained from normal mice and mice with Pa04C tumors and mice with Pa04C tumors with SLC1A5 downregulated. Method: Patient derived cachexia-inducing Pa04C pancreatic cancer cells were lentivirally transduced to express shRNA to stably downregulate SLC1A5. Mice were euthanized once tumors were ~500 mm3, the spleen and pancreas were excised and snap frozen. Snap frozen spleen (normal n= 5, Pa04C n= 11, Pa04C_SLC1A5 n= 10) and pancreas (normal n= 4, Pa04C n= 16, Pa04C_SLC1A5 n= 10) tissue samples were pulverized for dual phase extraction. The aqueous phase was used for 1H MRS analysis. Topspin 3.5 software was used for data processing and analyses. Results and Discussion: Significant downregulation of SLC1A5 mRNA and protein was confirmed in Pa04C_SLC1A5 cells and tumors. SLC1A5 downregulation resulted in significant growth delay and attenuation of weight loss. A comparison of normal mice vs empty vector/wild type tumor (EV/WT) bearing mice identified significant changes in succinate, aspartate and fumarate in the spleen, lactate, acetate, pyruvate, methionine, asparagine, creatine, choline phosphocholine, uracil, histidine and phenylalanine in the pancreas, with leucine, isoleucine, valine, alanine, glutamate, glutamine, glutathione, glycerophosphocholine, glycine, glucose and tyrosine commonly altered in the spleen and pancreas. A comparison of normal vs Pa04C_ SLC1A5 tumor bearing mice identified similar metabolic changes in the spleen and pancreas but these were reduced. Fumarate did not change in the spleen, and of the metabolic changes common to spleen and pancreas, glutamine did not change when tumor SLC1A5 was downregulated. Metabolite changes induced only in the pancreas were also similar to normal vs EV/WT with the exception of a change in glutamine with SLC1A5 downregulation and no change in lactate. Our data highlight the profound metabolic changes in spleen and pancreas metabolism that occur with growth of a cachexia-inducing pancreatic cancer xenograft, and the impact on these metabolic patterns as a result of downregulating the glutamine transporter in these cancer cells. The metabolic patterns identified in the spleen and pancreas may provide novel targets to reduce the morbidity from cachexia. Reference: 1. Son J et al, Nature. 2013;496(7443):101-5. Citation Format: Raj Kumar Sharma, Santosh Kumar Bharti, Balaji Krishnamachary, Yelena Mironchik, Paul Winnard Jr., Marie-France Penet, Zaver M. Bhujwalla. Metabolic changes in the spleen and pancreas induced by PDAC xenografts with or without glutamine transporter downregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6353.

Cancer-induced cachexia is commonly observed in pancreatic cancer. The syndrome induces significant weight loss and leads to morbidity, intolerance to chemotherapy, and mortality. While performing metabolic characterization of the brain and plasma of mice with a cachexia-inducing human pancreatic cancer xenograft we identified significant changes in glutamine metabolism [1] that led us to investigate the effects of altering tumor glutamine metabolism on weight loss. We genetically engineered cachexia inducing Pa04C cells to express shRNA downregulating the glutamine transporter SLC1A5. Tumors derived from Pa04C cells with downregulated SLC1A5 (CSh cells and tumors) exhibited significantly delayed tumor growth compared to empty vector (EV) or wild type (WT) tumors, but escaped growth delay approximately 60 days after inoculation, although SLC1A5 mRNA and protein remained significantly downregulated. Despite tumor growth, mouse weight reduction was significantly attenuated at matched EV and CSh tumor volumes. We next sought to investigate if tumors derived from cells isolated from escaped CSh tumor (TSh cells and tumors) continued to exhibit growth delay and attenuated weight loss when re-inoculated in mice. Quantitative transcriptome profiling by RNA-seq was performed to determine differentially expressed genes in CSh and TSh cells compared to EV cells. Method: EV, CSh or TSh cells were inoculated subcutaneously in male mice. Tumor volumes and weights of tumor bearing mice were recorded until tumors were harvested at ~ 500 mm3 for molecular characterization. RNA was isolated in triplicate from EV, CSh and TSh cells. Transcriptomic analysis was performed by RNA sequencing on a NovaSeq 6000 PE150 platform. All bioinformatics analysis was performed with assistance from the NOVOGENE informatics group. Results: Tumors derived from TSh cells did not exhibit any growth delay unlike tumors derived from CSh cells. SLC1A5 expression remained downregulated in TSh cells and tumors. Despite the loss of growth delay, mice with TSh tumors continued to exhibit attenuated weight loss identifying, suggesting the glutamine transporter as a potential treatment strategy to reduce cachexia. Transcriptomic analysis allowed us to identify the adaptive changes that occurred in CSh tumors that allowed these tumors to escape growth delay despite SLC1A5 downregulation. Transcriptomic differences between TSh and CSh cells were primarily in pathways related to amino acid metabolism, inflammation and the extracellular matrix. These transcriptomic differences allow the identification of novel targets that can be used in combination with glutamine transporter downregulation to arrest the growth of pancreatic cancer cells in vivo. Supported by NIH R35 CA209960 and R01 CA193365. 1) J Cachexia Sarcopenia Muscle. 2020 Dec; 11(6): 1487-1500. Citation Format: Balaji Krishnamachary, Ishwarya Sivakumar, Yelena Mironchik, Raj Kumar Sharma, Santosh Kumar Bharti, Marie-France Penet, Paul Winnard, Eibhlin Goggins, Jiefu Jin, Anirban Maitra, Michael G. Goggins, Zaver M. Bhujwalla. Downregulation of glutamine transporter stably and significantly attenuates weight loss by a cachexia-inducing pancreatic cancer xenograft [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6305.

Small interfering RNA are suitable for gene silencing through a sequence-specific RNA interference process. The redundancy and complexity of molecular pathways in cancer create a need for multiplexed targeting that can be achieved with multiplexed siRNA delivery. Here we delivered multiplexed siRNA with a PSMA-targeted biocompatible dextran nanoparticle (NP) to downregulate CD46 and PD-L1 siRNA in PSMA expressing prostate cancer cells. The multiplexed gene targets selected, PD-L1 and CD46, play important roles in the escape of cancer cells from immune surveillance. PSMA is abundantly expressed by prostate cancer cells allowing prostate cancer specific delivery of the NPs. The NP was decorated with acid cleavable amine functional groups through acetal bonds that undergo degradation under acidic conditions providing rapid release of siRNA. Cell imaging and flow cytometry studies confirmed PSMA-specific delivery of CD46 and PD-L1 siRNA to high PSMA expressing PC-3 PIP cells. Immunoblot, qRT-PCR and flow cytometry confirmed downregulation of CD46 and PD-L1 following treatment with multiplexed siRNA at a concentration of 50 nM. These studies pave the way for delivering multiplexed siRNA to tumors in vivo to unmask tumors to the immune system using PSMA targeted biocompatible NPs. Citation Format: Zhihang Chen, Balaji Krishnamachary, Yelena Mironchik, Sangeeta R. Banerjee, Martin G. Pomper, Zaver M. Bhujwalla. Prostate-specific membrane antigen (PSMA) targeted multiplexed siRNA-mediated gene silencing of CD46 and PD-L1 in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5070.

Background Harnessing the power of the immune system by using immune checkpoint inhibitors has resulted in some of the most exciting advances in cancer treatment. The full potential of this approach has, however, not been fully realized for treating many cancers such as pancreatic and breast cancer. Cancer metabolism influences many aspects of cancer progression including immune surveillance. An expanded understanding of how cancer metabolism can directly impact immune checkpoints may allow further optimization of immunotherapy. We therefore investigated, for the first time, the relationship between the overexpression of choline kinase-α (Chk-α), an enzyme observed in most cancers, and the expression of the immune checkpoint PD-L1. Methods We used small interfering RNA to downregulate Chk-α, PD-L1, or both in two triple-negative human breast cancer cell lines (MDA-MB-231 and SUM-149) and two human pancreatic ductal adenocarcinoma cell lines (Pa09C and Pa20C). The effects of the downregulation were studied at the genomic, proteomic, and metabolomic levels. The findings were compared with the results obtained by the analysis of public data from The Cancer Genome Atlas Program. Results We identified an inverse dependence between Chk-α and PD-L1 at the genomic, proteomic, and metabolomic levels. We also found that prostaglandin-endoperoxide synthase 2 (COX-2) and transforming growth factor beta (TGF-β) play an important role in this relationship. We independently confirmed this relationship in human cancers by analyzing data from The Cancer Genome Atlas Program. Conclusions Our data identified previously unknown roles of PD-L1 in cancer cell metabolic reprogramming, and revealed the immunosuppressive increased PD-L1 effect of Chk-α downregulation. These data suggest that PD-L1 regulation of metabolism may be mediated through Chk-α, COX-2, and TGF-β. The observations provide new insights that can be applied to the rational design of combinatorial therapies targeting immune checkpoints and cancer metabolism.

RationaleExtracellular vesicles (EVs) have emerged as important mediators in cell-cell communication and disease pathogenesis; however, their relevance in pulmonary hypertension (PH) secondary to HIV infection is yet to be explored.ObjectiveTo examine the role of circulating small EVs and monocyte-derived macrophage (MDM) EVs in the development of HIV-associated PHMethodsEVs isolated from plasma of HIV-infected drug users and non-users with/without PH and from supernatants of HIV-infected MDMs treated with/without second hit of cocaine were studied for their effect on vascular dysfunction both in vitro and in vivo.Measurements and Main ResultsWe report significantly higher numbers of plasma derived EVs (PEVs) carrying higher levels of TGF-β1 in people living with HIV (PLWH) that had PH compared to non-PH PLWH. Importantly, levels of these TGF-β1 loaded PEVs correlated with pulmonary arterial systolic pressures, CD4 counts, but not with diffusion capacity for carbon monoxide or viral load. Correspondingly, enhanced TGF-β1-dependent pulmonary endothelial injury and smooth muscle hyperplasia was observed. Cocaine treatment of HIV-1 infected-MDMs resulted in increased number of TGF-β1 high-EVs. Intravenous injection of these EVs in rats led to increased right ventricle systolic pressure accompanied with myocardial injury and increased levels of serum endothelin-1, TNF-α, and cardiac Troponin-I. Conversely, pretreatment of rats with TGFβ-Receptor 1 inhibitor prevented these EV-mediated changes.ConclusionFindings define the ability of macrophage-derived small EVs to cause pulmonary vascular modeling and PH via modulation of TGF-β signaling and suggest clinical implications of circulating TGF-β high-EVs as a potential biomarker of HIV-PH.

COVID-19 infection caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in a global pandemic with the number of deaths growing exponentially. Early evidence points to significant endothelial dysfunction, micro-thromboses, pro-inflammation as well as a dysregulated immune response in the pathogenesis of this disease. In this study, we analyzed the cargo of EVs isolated from the plasma of patients with COVID-19 for the identifiction of potential biomarkers of disease severity and to explore their role in disease pathogenesis. Plasma-derived EVs were isolated from 53 hospitalized patients with COVID infection and compared according to the severity of the disease. Analysis of inflammatory and cardiovascular protein cargo of large EVs revealed significantly differentially expressed proteins for each disease sub-group. Notably, members of the TNF superfamily and IL-6 family were up-regulated in patients on oxygen support with severe and moderate disease. EVs from the severe group were also enhanced with pro-thrombotic/endothelial injury factors (TF, t-PA, vWF) and proteins associated with cardiovascular pathology (MB, PRSS8, REN, HGF). Significantly higher levels of TF, CD163, and EN-RAGE were observed in EVs from severe patients when compared to patients with a moderate disease requiring supplemental O2. Importantly, we also observed increased caspase 3/7 activity and decreased cell survival in human pulmonary microvascular endothelial cells exposed to EVs from the plasma of patients with severe disease compared to asymptomatic group. In conclusion, our findings indicate alterations in pro-inflammatory, coagulopathy, and endothelial injury protein cargo in large EVs in response to SARS-CoV-2 infection that may be a causative agent in severe illness.

Pulmonary arterial hypertension is a fatal disease associated with pulmonary vascular remodeling and right ventricular hypertrophy. Pre-clinical animal models that reproduce the human pulmonary arterial hypertension process and pharmacological response to available therapies are critical for future drug development. The most prevalent animal model reproducing many aspects of angioobliterative forms of pulmonary arterial hypertension is the rat Sugen/hypoxia model in which Sugen, a vascular endothelial growth factor receptor antagonist, primarily causes initiation of endothelial injury and later in the presence of hypoxia promotes proliferation of apoptosis-resistant endothelial cells. We previously demonstrated that exposure of human pulmonary microvascular endothelium to morphine and HIV-proteins results in initial apoptosis followed by increased proliferation. Here, we demonstrate that the double-hit of morphine and Sugen 5416 (Sugen–morphine) in rats leads to the development of pulmonary arterial hypertension with significant medial hypertrophy of pre-acinar pulmonary arteries along with neo-intimal thickening of intra-acinar vessels. In addition, the pulmonary smooth muscle and endothelial cells isolated from Sugen–morphine rats showed hyperproliferation and apoptotic resistance, respectively, in response to serum starvation. Our findings support that the dual hit model of Sugen 5416 and morphine provides another experimental strategy to induce significant pulmonary vascular remodeling and development of severe pulmonary arterial hypertension pathology in rats without exposure to hypoxia.

(1) Background: Despite advances in surgical approaches and drug development, ovarian cancer is still a leading cause of death from gynecological malignancies. Patients diagnosed with late-stage disease are treated with aggressive surgical resection and chemotherapy, but recurrence with resistant disease is often observed following treatment. There is a critical need for effective therapy for late-stage ovarian cancer. Photoimmunotherapy (PIT), using an antibody conjugated to a near infrared (NIR) dye, constitutes an effective theranostic strategy to detect and selectively eliminate targeted cell populations. (2) Methods: Here, we are targeting program death ligand 1 (PD-L1) using NIR-PIT in a syngeneic mouse model of ovarian cancer. PD-L1 PIT-mediated cytotoxicity was quantified in RAW264.7 macrophages and ID8-Defb29-VEGF cells in culture, and in vivo with orthotopic ID8-Defb29-VEGF tumors. (3) Results: Treatment efficacy was observed both in vitro and in vivo. (4) Conclusions: Our data highlight the need for further investigations to assess the potential of using NIR-PIT for ovarian cancer therapy to improve the treatment outcome of ovarian cancer.

Hypoxia inducible factors (HIFs) are transcription factors that mediate the response of cells to hypoxia. HIFs have wide-ranging effects on metabolism, the tumor microenvironment (TME) and the extracellular matrix (ECM). Here we investigated the silencing effects of two of the three known isoforms, HIF-1α and HIF-2α, on collagen 1 (Col1) fibers, which form a major component of the ECM of tumors. Using a loss-of-function approach for HIF-1α or 2α or both HIF-1α and 2α, we identified a relationship between HIFs and Col1 fibers in MDA-MB-231 tumors. Tumors derived from MDA-MB-231 cells with HIF-1α or 2α or both HIF-1α and 2α silenced contained higher percent fiber volume and lower inter-fiber distance compared to tumors derived from empty vector MDA-MB-231 cells. Depending upon the type of silencing, we observed changes in Col1 degrading enzymes, and enzymes involved in Col1 synthesis and deposition. Additionally, a reduction in lysyl oxidase protein expression in HIF-down-regulated tumors suggests that more non-cross-linked fibers were present. Collectively these results identify the role of HIFs in modifying the ECM and the TME and provide new insights into the effects of hypoxia on the tumor ECM.

Purpose: Effective in vivo delivery of siRNA to silence genes is a highly sought-after goal in the treatment of multiple diseases. Cyclooxygenase-2 (COX-2) is a major mediator of inflammation and its effective and specific downregulation has been of major interest to treat conditions ranging from auto-immune diseases to gastric inflammation and cancer. Here we developed a novel and efficient method to produce a multiple imaging reporter labeled cationic dextran nanopolymer with cleavable positive charge groups for COX-2 siRNA delivery. Methods: Small molecules containing amine groups were conjugated to the dextran scaffold through acetal bonds that were cleaved in weak acid conditions. With multiple imaging reporters located on different regions of the nanopolymer, cleavage of acetal bonds was visualized and quantified by imaging, for the first time, in cancer cells and tumors. Results: The biocompatibility of dextran and the rapid cleavage and release of amine groups minimized proinflammatory side effects and COX-2 induction observed with other siRNA carriers, to successfully achieve COX-2 downregulation in cancer cells and tumors. Imaging results confirmed that this nanoplex, consisting of the dextran nanopolymer with COX-2 siRNA, accumulated in tumors, and the amine functional groups were rapidly cleaved in cancer cells and tumors. Along with effective downregulation of COX-2, we also demonstrated, for the first time, effective downregulation of its major product prostaglandin E2 (PGE2). Conclusions: We successfully developed an efficient method to produce an acid-degradable dextran nanopolymer containing cleavable amine groups as the siRNA carrier. Because of its biocompatibility, this degradable dextran delivered COX-2 siRNA within tumors and efficiently downregulated COX-2 expression.

Purpose: The poor prognosis of metastatic prostate cancer continues to present a major challenge in prostate cancer treatment. The tumor extracellular matrix (ECM) plays an important role in facilitating metastasis. Here, we investigated the structure and function of an ECM that facilitates prostate cancer metastasis by comparing orthotopic tumors that frequently metastasize to poorly metastatic subcutaneous tumors. Experimental Design: Both tumors were derived from a human prostate cancer PC3 cell line engineered to fluoresce under hypoxia. Second harmonic generation (SHG) microscopy was used to characterize collagen 1 (Col1) fiber patterns in the xenografts as well as in human samples. MRI was used to determine albumin-Gd-diethylenetriaminepenta-acetate (alb-GdDTPA) transport through the ECM using a saturation recovery MR method combined with fast T1 SNAPSHOT-FLASH imaging. Cancer-associated fibroblasts (CAF) were also quantified in these tumors. Results: Significant structural and functional differences were identified in the prometastatic orthotopic tumor ECM compared to the less metastatic subcutaneous tumor ECM. The significantly higher number of CAFs in orthotopic tumors may explain the higher Col1 fiber volumes in these tumors. In vivo, alb-GdDTPA pooling was significantly elevated in metastatic orthotopic tumors, consistent with the increased Col1 fibers. Conclusions: Developing noninvasive MRI indices of macromolecular transport, together with characterization of Col1 fiber patterns and CAFs can assist in stratifying prostate cancers for aggressive treatments or active surveillance. These results highlight the role of CAFs in supporting or creating aggressive cancers, and the importance of depleting CAFs to prevent metastatic dissemination in prostate cancer. Clin Cancer Res; 23(9); 2245–54. ©2016 AACR.

Because of the spatial and temporal heterogeneities of cancers, technologies to investigate cancer cells and the consequences of their interactions with abnormal physiological environments, such as hypoxia and acidic extracellular pH, with stromal cells, and with the extracellular matrix, under controlled conditions, are valuable to gain insights into the functioning of cancers. These insights can lead to an understanding of why cancers invade and metastasize, and identify effective treatment strategies. Here we have provided an overview of the applications of MRI/MRS/MRSI to investigate intact perfused cancer cells, their metabolism and invasion, and their interactions with stromal cells and the extracellular matrix.

Collagen 1 (Col1) fibers play an important role in tumor interstitial macromolecular transport and cancer cell dissemination. Our goal was to understand the influence of Col1 fibers on water diffusion, and to examine the potential of using noninvasive diffusion tensor imaging (DTI) to indirectly detect Col1 fibers in breast lesions. We previously observed, in human MDA-MB-231 breast cancer xenografts engineered to fluoresce under hypoxia, relatively low amounts of Col1 fibers in fluorescent hypoxic regions. These xenograft tumors together with human breast cancer samples were used here to investigate the relationship between Col1 fibers, water diffusion and anisotropy, and hypoxia. Hypoxic low Col1 fiber containing regions showed decreased apparent diffusion coefficient (ADC) and fractional anisotropy (FA) compared to normoxic high Col1 fiber containing regions. Necrotic high Col1 fiber containing regions showed increased ADC with decreased FA values compared to normoxic viable high Col1 fiber regions that had increased ADC with increased FA values. A good agreement of ADC and FA patterns was observed between in vivo and ex vivo images. In human breast cancer specimens, ADC and FA decreased in low Col1 containing regions. Our data suggest that a decrease in ADC and FA values observed within a lesion could predict hypoxia, and a pattern of high ADC with low FA values could predict necrosis. Collectively the data identify the role of Col1 fibers in directed water movement and support expanding the evaluation of DTI parameters as surrogates for Col1 fiber patterns associated with specific tumor microenvironments as companion diagnostics and for staging.