Pal, Krishnendu

Optineurin (OPTN) is a multifunctional adaptor protein that regulates diverse cellular processes, including inflammatory signaling, autophagy, vesicular trafficking, and immune responses. This multifaceted role of OPTN is made possible by the presence of a complex structure comprising multiple domains that interact with different proteins to exert various functions important for modulating key signaling processes. Mutations in OPTN are linked with several human pathologies including glaucoma, Paget’s disease of bone, Crohn’s disease, and neurodegenerative diseases such as amyotrophic lateral sclerosis, and dementia. Emerging evidence suggests that OPTN has a complex and context-dependent role in cancer biology as well. It is upregulated in pancreatic ductal adenocarcinoma and hepatocellular carcinoma but downregulated in lung and colorectal cancers, indicating its dual role as a potential oncogene or tumor suppressor depending on the cellular environment. Additionally, OPTN plays a critical role in preventing immune evasion in colorectal cancer by maintaining interferon-gamma receptor 1 (IFNGR1) expression and supporting dendritic cell-mediated T-cell priming, thereby enhancing antitumor immune responses. Despite its significance in oncogenic pathways and immune regulation, the therapeutic potential of targeting OPTN in cancer remains largely unexplored. This review aims to provide a comprehensive understanding of OPTN’s pleiotropic functions, highlighting its role in autophagy, inflammation, immune surveillance, and cancer progression. By elucidating its diverse regulatory mechanisms, we seek to encourage further research into the therapeutic implications of OPTN in cancer treatment and immunotherapy.

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by aggressive tumor biology, poor vascularization, dense stromal barriers, and profound resistance to chemotherapy. GAIP-interacting protein C-terminus 1 (GIPC1), a PDZ-domain-containing adaptor protein, is highly overexpressed in PDAC and plays a critical role in tumor progression and chemoresistance. This study aimed to develop and evaluate a novel tumor-targeted liposomal siRNA delivery system (LGIPCsi) to silence GIPC1 and enhance the therapeutic efficacy of gemcitabine (GEM) in PDAC; Methods: LGIPCsi nanoparticles were synthesized and optimized for physicochemical stability, siRNA complexation efficiency, and tumor-targeting capability. Their therapeutic efficacy was assessed using in vitro pancreatic cancer cell models and in vivo orthotopic and patient-derived xenograft (PDX) models of PDAC. Biodistribution, tumor uptake, and antitumor efficacy were evaluated following systemic administration. Combination studies were performed to assess the synergistic effects of LGIPCsi and GEM; Results: GIPC1 silencing significantly sensitized pancreatic cancer cells to GEM, resulting in enhanced inhibition of tumor cell proliferation in vitro. In vivo, systemic administration of LGIPCsi achieved efficient intratumoral delivery of siGIPC1, leading to marked tumor growth suppression. Combination therapy with GEM and LGIPCsi produced synergistic antitumor effects, with substantial tumor regression compared to monotherapy groups. Importantly, no significant systemic toxicity was observed in treated animals; Conclusions: This study identifies GIPC1 as a promising therapeutic target in PDAC and demonstrates that tumor-targeted siRNA nanomedicine can effectively overcome chemoresistance when combined with standard chemotherapy. The LGIPCsi platform offers a rational and translational strategy to enhance treatment efficacy in PDAC through targeted RNAi-based combination therapy.

Despite recent advancements, effective treatment for pancreatic ductal adenocarcinoma (PDAC) has remained elusive. The overall survival rate in PDAC patients has been dismally low due to resistance to standard therapies. In fact, the failure of monotherapies to provide long-term survival benefits in patients led to ascension of several combination therapies for PDAC treatment. However, these combination therapies provided modest survival improvements while increasing treatment-related adverse side effects. Hence, recent developments in drug delivery methods hold the potential for enhancing therapeutic benefits by offering cocktail drug loading and minimizing chemotherapy-associated side effects. Nanoformulations-aided deliveries of anticancer agents have been a success in recent years. Yet, improving the tumor-targeted delivery of drugs to PDAC remains a major hurdle. In the present paper, we developed several new tumor-targeted dual intervention-oriented drug-encapsulated (DIODE) liposomes. We successfully formulated liposomes loaded with gemcitabine (G), paclitaxel (P), erlotinib (E), XL-184 (c-Met inhibitor, X), and their combinations (GP, GE, and GX) and evaluated their in vitro and in vivo efficacies. Our novel DIODE liposomal formulations improved median survival in comparison with gemcitabine-loaded liposomes or vehicle. Our findings are suggestive of the importance of the targeted delivery for combination therapies in improving pancreatic cancer treatment.

Schematic representation demonstrating the fabrication and in vivo evaluation of an immune-modulatory nano-formulation consisting of irinotecan and curcumin in immune-competent mouse models of pancreatic adenocarcinoma.

Abstract Quiescin sulfhydryl oxidase 1 (QSOX1) is an enzyme overexpressed by many different tumor types. QSOX1 catalyzes the formation of disulfide bonds in proteins. Because short hairpin knockdowns (KD) of QSOX1 have been shown to suppress tumor growth and invasion in vitro and in vivo, we hypothesized that chemical compounds inhibiting QSOX1 enzymatic activity would also suppress tumor growth, invasion, and metastasis. High throughput screening using a QSOX1-based enzymatic assay revealed multiple potential QSOX1 inhibitors. One of the inhibitors, known as “SBI-183,” suppresses tumor cell growth in a Matrigel-based spheroid assay and inhibits invasion in a modified Boyden chamber, but does not affect viability of nonmalignant cells. Oral administration of SBI-183 inhibits tumor growth in 2 independent human xenograft mouse models of renal cell carcinoma. We conclude that SBI-183 warrants further exploration as a useful tool for understanding QSOX1 biology and as a potential novel anticancer agent in tumors that overexpress QSOX1.

Abstract Resistance to chemotherapy remains a major obstacle to improving outcomes of cancer treatment. Recent data suggest intrinsic functions of immune checkpoint proteins, including PD-L1, that may be distinct from their immunoregulatory roles. We found that colorectal cancer (CRC) cells with mutant BRAF(V600E) or KRASalleles show increased PD-L1 transcripts and expression of cell surface PD-L1 protein compared to those with wild-type copies. Furthermore, ectopic expression of BRAFV600E or mutant KRAS induced PD-L1 whose upregulation was attenuated by inhibition of RAS-RAF-MEK-ERK signaling. Combined knockdown of MEK/ERK effectors c-JUN and YAP markedly reduced PD-L1. Knockout of PD-L1 in RKO cells resulted in a reduction in chemotherapy-induced DNA double strand breaks (pH2AX) and caspase-3 cleavage compared to parental cells. Results were confirmed in PD-L1 knockout MC38 murine CRC cells where re-expression of PD-L1, but not its deletion mutants, was shown to induced pH2AX and apoptosis. In cells with knockout of PD-L1, reductions in p-AKT and the BH3-only proteins BIM and BIK were observed that could be restored by re-expression of PD-L1. Treatment of cells with an anti-PD-L1 antibody reduced p-AKT, BIM and BIK, and also attenuated chemotherapy-induced apoptosis. Re-expression of BIM in PD-L1 knockout cells restored apoptosis. Murine tumor xenografts generated from cells with knockout of PD-L1 displayed resistance to oxaliplatin-induced tumor regression compared to tumors derived from parental cells. Using TCGA datasets, human CRCs with high vs low PD-L1 mRNA levels were significantly associated with better survival. In summary, we identified a non-immune function of tumor cell-intrinsic PD-L1 that upregulates BH3-only proteins BIM and BIK to promote apoptosis, thereby suggesting its potential as a predictive biomarker. Citation Format: Daofu Feng, Krishnendu Pal, Debabrata Mukhopadhyay, Xin Liu, Haidong Dong, Shengbing Huang, Frank A. Sinicrope. Tumor intrinsic PD-L1 is mediated by BRAFV600E and can regulate drug-induced apoptosis in human colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 705.

ABSTRACT Aggregated amyloid β (Aβ) peptides in the Alzheimer's disease (AD) brain are hypothesized to trigger several downstream pathologies, including cerebrovascular dysfunction. Previous studies have shown that Aβ peptides can have antiangiogenic properties, which may contribute to vascular dysfunction in the early stages of the disease process. We have generated data showing that brain endothelial cells (ECs) exposed to toxic Aβ1‐42 oligomers can readily enter a senescence phenotype. To determine the effect of Aβ oligomers on brain ECs, we treated early passaged human brain microvascular ECs and HUVECs with high MW Aβ1‐42 oligomers (5 µM, for 72 h). For controls, we used no peptide treatment, 5 µM Aβ1‐42 monomers, and 5 µM Aβ1‐42 fibrils, respectively. Brain ECs treated with Aβ1‐42 oligomers showed increased senescence‐associated β‐galactosidase staining and increased senescence‐associated p21/ p53 expression. Treatment with either Aβ1‐42 monomer or Aβ1‐42 fibrils did not induce senescence in this assay. We then measured vascular endothelial growth factor receptor (VEGFR) expression in the Aβ1‐42 oligomer‐treated ECs, and these cells showed significantly increased VEGFR‐1 expression and decreased VEGFR‐2 levels. Overexpression of VEGFR‐1 in brain ECs readily induced senescence, suggesting a direct role of VEGFR‐1 signaling events in this paradigm. More importantly, small interfering RNA‐mediated knockdown of VEGFR‐1 expression in brain ECs was able to prevent up‐regulation of p21 protein expression and significantly reduced induction of senescence following Aβ1‐42 oligomer treatment. Our studies show that exposure to Aβ1‐42 oligomers may impair vascular functions by altering VEGFR‐1 expression and causing ECs to enter a senescent phenotype. Altered VEGFR expression has been documented in brains of AD patients and suggests that this pathway may play a role in AD disease pathogenesis. These studies suggest that modulating VEGFR‐1 expression and signaling events could potentially prevent senescence and rejuvenate EC functions, and provides us with a novel target to pursue for prevention and treatment of cerebrovascular dysfunction in AD.—Angom, R. S., Wang, Y., Wang, E., Pal, K., Bhattacharya, S., Watzlawik, J. O., Rosenberry, T. L., Das, P., Mukhopadhyay, D. VEGF receptor‐1 modulates amyloid β 1–42 oligomer‐induced senescence in brain endothelial cells. FASEB J. 33, 4626–4637 (2019). www.fasebj.org

Tumor-selective uptake of plectin-1 targeting peptide-modified gold nanoparticles ameliorates targeted delivery of gemcitabine in pancreatic ductal adenocarcinoma.