Anticachectic regulator analysis reveals Perp-dependent antitumorigenic properties of 3-methyladenine in pancreatic cancer

Fucoxanthin suppresses pancreatic cancer progression by inducing bioenergetics metabolism crisis and promoting SLC31A1‑mediated sensitivity to DDP

Pancreatic cancer (PC) is one of the most malignant tumors, with a 5‑year survival rate <10%. Chemosynthetic drugs are widely used in the treatment of PC; however, their toxicity and side effects often reduce the quality of life for patients. MTT and colony formation assay were performed to detect cell growth and viability in PC cells. Levels of ROS in whole cell and mitochondria were analyzed through flow cytometry. ATP production was evaluated using an ATP Assay Kit. Cellular bioenergetics were analyzed with a Seahorse XFe96 Analyzer, and changes in target molecules were monitored by western blotting. The present study reports that fucoxanthin (FX), a carotenoid derived from aquatic brown seaweed, significantly inhibits PC by inhibiting cell proliferation and inducing cell death via the non‑classical pathway. FX switches mitochondrial respiration to aerobic glycolysis in PC cells. Furthermore, FX decreases whole‑cell ATP levels, which indicates that promotion of glycolysis does not compensate for FX‑induced ATP depletion in mitochondria. Moreover, FX decreased the reduced glutathione/oxidized glutathione ratio observed under glucose‑limited conditions. These alterations caused by FX may decrease metabolic flexibility, indicating higher sensitivity to glucose‑limited (GL) conditions. FX increased the cytotoxicity of cisplatin (DDP) and the expression of solute carrier family 31 member 1 (SLC31A1) in PC cells. Furthermore, the knockdown of SLC31A1 can attenuate cytotoxicity caused by the combination of FX and DDP. It was inferred that FX increased the sensitivity of PC cells to DDP), potentially by upregulating SLC31A1 expression. In conclusion, FX exhibited potent antitumor effects by reprogramming energy metabolism and inducing a distinct form of regulated cell death. Therefore, combining FX with GL treatment or DDP presents a promising therapeutic strategy for PC.

Co-delivery of hsa-miR-34a and 3-methyl adenine by a self-assembled cellulose-based nanocarrier for enhanced anti-tumor effects in HCC

The simultaneous delivery of oligonucleotides and small molecules has garnered significant interest in cancer therapy. Hepatocellular carcinoma (HCC) treatment is hindered by limited efficacy and significant side effects. Homo sapiens microRNA-34a (hsa-miR-34a) has tumor suppressor properties and like small molecule 3-methyl adenine (3MA) can inhibit autophagy. Besides, 3MA has been shown to enhance anticancer effects in combination therapies. In the present study, a novel modified-cellulose-dialdehyde (MDAC) nanocarrier responsive to lysosomal pH was designed to co-load hsa-miR-34a polyplexes and 3MA and evaluate its antitumor efficacy against HCC. Polyplexes containing hsa-miR-34a and poly L lysine (PLL) with an optimal N/P ratio exhibited a zeta potential of +9.28. These polycations significantly modulated the surface charge of 3MA MDAC for optimal cell-membrane transport and dramatically increased their stability. The PLL-miR34a/3MA MDAC NPs had loading efficiency of around 99.7 % for miR-34a and 35 % for 3MA. Comply with pH dependency, PLL-miR34a polyplex/3MA MDAC NPs worked very efficiently on the inhibiting the expression of autophagy genes (p < 0.05), preventing the formation of autophagosomal vacuoles, reducing rate of cell survival, anti-migratory effects (>100 %), and triggering apoptosis (67.15 %) in HepG2. Our cellulose-based nanocarrier may demonstrate potential for enhancing therapeutic efficacy of combination therapies headed for future clinical translation in HCC.

Modelling the micro- and macro- environment of pancreatic cancer: from patients to pre-clinical models and back

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with very low survival rates. Over the past 50 years, improvements in PDAC survival have significantly lagged behind the progress made in other cancers. PDAC's dismal prognosis is due to typical late-stage diagnosis combined with lack of effective treatments and complex mechanisms of disease. We propose that improvements in survival are partly hindered by the current focus on largely modelling and targeting PDAC as one disease, despite it being heterogeneous. Implementing new disease-representative pre-clinical mouse models that capture this complexity could enable the development of transformative therapies. Specifically, these models should recapitulate human PDAC late-stage biology, heterogeneous genetics, extensive non-malignant stroma, and associated risk factors and comorbidities. In this Perspective, we focus on how pre-clinical mouse models could be improved to exemplify key features of PDAC micro- and macro- environments, which would drive clinically relevant patient stratification, tailored treatments and improved survival.

Targeted Mevalonate Pathway and Autophagy in Antitumor Immunotherapy

Tumors of the digestive system are currently one of the leading causes of cancer-related death worldwide. Despite considerable progress in tumor immunotherapy, the prognosis for most patients remains poor. In the tumor microenvironment (TME), tumor cells attain immune escape through immune editing and acquire immune tolerance. The mevalonate pathway and autophagy play important roles in cancer biology, antitumor immunity, and regulation of the TME. In addition, there is metabolic crosstalk between the two pathways. However, their role in promoting immune tolerance in digestive system tumors has not previously been summarized. Therefore, this review focuses on the cancer biology of the mevalonate pathway and autophagy, the regulation of the TME, metabolic crosstalk between the pathways, and the evaluation of their efficacy as targeted inhibitors in clinical tumor immunotherapy.

A TGF-β/KLF10 signaling axis regulates atrophy-associated genes to induce muscle wasting in pancreatic cancer

Cancer cachexia, and its associated complications, represent a large and currently untreatable roadblock to effective cancer management. Many potential therapies have been proposed and tested-including appetite stimulants, targeted cytokine blockers, and nutritional supplementation-yet highly effective therapies are lacking. Innovative approaches to treating cancer cachexia are needed. Members of the Kruppel-like factor (KLF) family play wide-ranging and important roles in the development, maintenance, and metabolism of skeletal muscle. Within the KLF family, we identified KLF10 upregulation in a multitude of wasting contexts-including in pancreatic, lung, and colon cancer mouse models as well as in human patients. We subsequently interrogated loss-of-function of KLF10 as a potential strategy to mitigate cancer associated muscle wasting. In vivo studies leveraging orthotopic implantation of pancreas cancer cells into wild-type and KLF10 KO mice revealed significant preservation of lean mass and robust suppression of pro-atrophy muscle-specific ubiquitin ligases Trim63 and Fbxo32, as well as other factors implicated in atrophy, calcium signaling, and autophagy. Bioinformatics analyses identified Transforming growth factor beta (TGF-β), a known inducer of KLF10 and cachexia promoting factor, as a key upstream regulator of KLF10. We provide direct in vivo evidence that KLF10 KO mice are resistant to the atrophic effects of TGF-β. ChIP-based binding studies demonstrated direct binding to Trim63, a known wasting-associated atrogene. Taken together, we report a critical role for the TGF-β/KLF10 axis in the etiology of pancreatic cancer-associated muscle wasting and highlight the utility of targeting KLF10 as a strategy to prevent muscle wasting and limit cancer-associated cachexia.

Blocking muscle wasting via deletion of the muscle-specific E3 ubiquitin ligase MuRF1 impedes pancreatic tumor growth

Cancer-induced muscle wasting reduces quality of life, complicates or precludes cancer treatments, and predicts early mortality. Herein, we investigated the requirement of the muscle-specific E3 ubiquitin ligase, MuRF1, for muscle wasting induced by pancreatic cancer. Murine pancreatic cancer (KPC) cells, or saline, were injected into the pancreas of WT and MuRF1-/- mice, and tissues analyzed throughout tumor progression. KPC tumors induced progressive wasting of skeletal muscle and systemic metabolic reprogramming in WT mice, but not MuRF1-/- mice. KPC tumors from MuRF1-/- mice also grew slower, and showed an accumulation of metabolites normally depleted by rapidly growing tumors. Mechanistically, MuRF1 was necessary for the KPC-induced increases in cytoskeletal and muscle contractile protein ubiquitination, and the depression of proteins that support protein synthesis. Together, these data demonstrate that MuRF1 is required for KPC-induced skeletal muscle wasting, whose deletion reprograms the systemic and tumor metabolome and delays tumor growth.

Molecular signatures of inherited and acquired sporadic late onset nemaline myopathies

Acquired sporadic late onset nemaline myopathy (SLONM) and inherited nemaline myopathy (iNM) both feature accumulation of nemaline rods in muscle fibers. Unlike iNM, SLONM is amenable to therapy. The distinction between these disorders is therefore crucial when the diagnosis remains ambiguous after initial investigations. We sought to identify biomarkers facilitating this distinction and to investigate the pathophysiology of nemaline rod formation in these different disorders. Twenty-two muscle samples from patients affected by SLONM or iNM underwent quantitative histological analysis, laser capture microdissection for proteomic analysis of nemaline rod areas and rod-free areas, and transcriptomic analysis. In all iNM samples, nemaline rods were found in subsarcolemmal or central aggregates, whereas they were diffusely distributed within muscle fibers in most SLONM samples. In SLONM, muscle fibers harboring nemaline rods were smaller than those without rods. Necrotic fibers, increased endomysial connective tissue, and atrophic fibers filled with nemaline rods were more common in SLONM. Proteomic analysis detected differentially expressed proteins between nemaline rod areas and rod-free areas, as well as between SLONM and iNM. These differentially expressed proteins implicated immune, structural, metabolic, and cellular processes in disease pathophysiology. Notably, immunoglobulin overexpression with accumulation in nemaline rod areas was detected in SLONM. Transcriptomic analysis corroborated proteomic findings and further revealed substantial gene expression differences between SLONM and iNM. Overall, we identified unique pathological and molecular signatures associated with SLONM and iNM, suggesting distinct underlying pathophysiological mechanisms. These findings represent a step towards enhanced diagnostic tools and towards development of treatments for SLONM.

Muscle and Bone Defects in Metastatic Disease

PURPOSE OF REVIEW

The present review addresses most recently identified mechanisms implicated in metastasis-induced bone resorption and muscle-wasting syndrome, known as cachexia.

RECENT FINDINGS

Metastatic disease in bone and soft tissues is often associated with skeletal muscle defects. Recent studies have identified a number of secreted molecules and extracellular vesicles that contribute to cancer cell growth and metastasis leading to bone destruction and muscle atrophy. In addition, alterations in muscle microenvironment including dysfunctions in hepatic and mitochondrial metabolism have been implicated in cancer-induced regeneration defect and muscle loss. Moreover, we review novel in vitro and animal models including promising new drug candidates for bone metastases and cancer cachexia. Preservation of bone health could be highly beneficial for maintaining muscle mass and function. Therefore, a better understanding of molecular pathways implicated in bone and muscle crosstalk in metastatic disease may provide new insights and identify new strategies to improve current anticancer therapeutics.