Porphyrias are rare, mostly inherited disorders resulting from altered activity of specific enzymes in the haem synthesis pathway that lead to accumulation of pathway intermediates. Photocutaneous symptoms occur when excess amounts of photoreactive porphyrins circulate in the blood to the skin, whereas increases in potentially neurotoxic porphyrin precursors are associated with neurovisceral symptoms. Current therapies are suboptimal and their mechanisms are not well established. As described here, emerging therapies address underlying disease mechanisms by introducing a gene, RNA or other specific molecule with the potential to cure or slow progression of the disease. Recent progress in nanotechnology and nanoscience, particularly regarding particle design and formulation, is expanding disease targets. More secure and efficient drug delivery systems have extended our toolbox for transferring specific molecules, especially into hepatocytes, and led to proof‐of‐concept studies in animal models. Repurposing existing drugs as molecular chaperones or haem synthesis inhibitors is also promising. This review summarizes key examples of these emerging therapeutic approaches and their application for hepatic and erythropoietic porphyrias.

Altered lipid metabolism is a common hallmark of various cancers, including intrahepatic cholangiocarcinoma (ICC), a highly lethal carcinoma that lacks effective treatment options. To elucidate the lipid metabolism changes in ICC, we coupled the expression of the firefly luciferase gene (FFL) to AKT1 (AKT-FFL) via an IRES linker, and then hydrodynamically injected mice with AKT-FFL and Notch1 intracellular cytoplasmic domain (NICD) to establish a luciferase-positive ICC model. This model not only enabled us to monitor and quantify tumor growth by injecting the mice with luciferin, but also allowed us to assess the fatty acid uptake rate by injecting the mice with free fatty acid luciferin (FFA-Luc). The ICC model exhibited robust uptake of exogenous fatty acids compared with the HCC model induced by AKT-FFL/ neuroblastoma Ras (Ras). Lipidomics analysis showed a dramatically higher level of fatty acid in ICC, further supporting the increased fatty acids uptake. Mechanistic studies identified FATP5 as the predominant mediator of fatty acid uptake required for ICC growth using Fatp5 knockout mice and AAV-based shRNA silencing of Fatp5. Our study discovered a novel therapeutic target for the treatment of ICC and shed light on the contributions of lipid metabolism to ICC development. Implications: This study provides the first in vivo evidence that FATP5 is a potential therapeutic target for treating ICC.

Background and Objectives: Aberrant upregulation of fatty acid synthase (FASN), catalyzing de novo synthesis of fatty acids, occurs in various tumor types, including human hepatocellular carcinoma (HCC). Although FASN oncogenic activity seems to reside in its pro-lipogenic function, cumulating evidence suggests that FASN’s tumor-supporting role might also be metabolic-independent. Materials and Methods: In the present study, we show that FASN inactivation by specific small interfering RNA (siRNA) promoted the downregulation of the S-phase kinase associated-protein kinase 2 (SKP2) and the consequent induction of p27^KIP1 in HCC cell lines. Results: Expression levels of FASN and SKP2 directly correlated in human HCC specimens and predicted a dismal outcome. In addition, forced overexpression of SKP2 rendered HCC cells resistant to the treatment with the FASN inhibitor C75. Furthermore, FASN deletion was paralleled by SKP2 downregulation and p27^KIP1 induction in the AKT-driven HCC preclinical mouse model. Moreover, forced overexpression of an SKP2 dominant negative form or a p27^KIP1 non-phosphorylatable (p27^KIP1-T187A) construct completely abolished AKT-dependent hepatocarcinogenesis in vitro and in vivo. Conclusions: In conclusion, the present data indicate that SKP2 is a critical downstream effector of FASN and AKT-dependent hepatocarcinogenesis in liver cancer, envisaging the possibility of effectively targeting FASN-positive liver tumors with SKP2 inhibitors or p27^KIP1 activators.

TBX3 behaves as a tumor suppressor or oncoprotein across cancer. However, TBX3 function remains undetermined in intrahepatic cholangiocarcinoma (iCCA), a deadly primary liver malignancy with few systemic treatment options. This study sought to investigate the impact of TBX3 on iCCA. We found that overexpression of TBX3 strongly inhibited human iCCA cell growth. In the Akt/FBXW7ΔF mouse iCCA model, overexpression of Tbx3 reduced cholangiocarcinogenesis in vivo, while inducible genetic knockout of Tbx3 accelerated iCCA growth. RNA-seq identified MAD2L1 as a downregulated gene in TBX3-overexpressing cells, and ChIP confirmed that TBX3 binds to the MAD2L1 promoter. CRISPR-mediated knockdown of Mad2l1 significantly reduced the growth of two iCCA models in vivo. Finally, we found that TBX3 expression is upregulated in ~20% of human iCCA samples, and its high expression is associated with less proliferation and better survival. MAD2L1 expression is upregulated in most human iCCA samples and negatively correlated with TBX3 expression. Altogether, our findings suggest that overexpression of TBX3 suppresses CCA progression via repressing MAD2L1 expression.

Acute intermittent porphyria (AIP) is a genetic metabolic disorder characterized by neurovisceral attacks. Although high-carbohydrate diets or intravenous glucose administration can help alleviate incipient attacks in patients, these interventions may also promote insulin resistance and increase metabolic risk. This study explored targeted dietary interventions to manage hyperinsulinemia and to enhance glucose uptake in insulin-sensitive organs under high-carbohydrate diet. Body composition and fecal microbiota profile were also investigated in a murine model of the disease. Wild-type and AIP mice ( n = 6/group) were supplemented with tapioca maltodextrin in drinking water for 12 weeks, alongside heat-treated Bifidobacterium animalis subsp. lactis CECT-8145 (BPL1®HT), its by-product lipoteichoic acid (LTA), or the insulin-sensitizing agent α-lipoic acid (α-LA). Liver-targeted therapies, previously assessed in AIP mice, were also included in this study. AIP mice on a high-carbohydrate diet exhibited hyperinsulinemia and tissue-specific differences in glucose uptake compared to wild-type mice. Dysbiosis, marked by reduced fecal Dorea spp. and Adlercreutzia muris , alongside higher abundance of Escherichia coli, was also showed. Supplementation with α-LA and LTA revealed superior ability to improve glucose tolerance test and skeletal muscle glucose uptake, reduce hyperinsulinemia, and enhance body composition by increasing lean mass relative to fat, compared to gene therapy or liver-targeted insulin administration. Notably, LTA restored fecal microbiota profiles resembling those of wild-type mice. In conclusion, supplementation with LTA from BPL1®HT and α-LA may represent promising dietary interventions to manage glucose tolerance, improve insulin sensitivity in muscle and adipose tissues, and potentially ameliorate body composition in AIP patients under a high-carbohydrate diet.

Gene expression levels of Fatp5, and Fasn were measured using qPCR in AAV-shSCR and AAV-shFatp5 ICC tumors.