The therapeutic resistance dilemma of malignant melanoma and the need for new treatment targets. Malignant melanoma is the most metastatic and lethal skin cancer. Although the introduction of BRAF inhibitors (e.g., Vemurafenib) and immune checkpoint inhibitors (anti‑PD‑1) has markedly improved clinical outcomes, the majority of patients acquire early drug resistance through dynamic genetic alterations. Central to these resistance mechanisms is cancer cell metabolic reprogramming, and mitochondrial deacetylase SIRT3, an epigenetic regulator within mitochondria, has been identified as a key axis supporting cancer cell survival and proliferation.

CRISPR/Cas9 and transcriptomic profiling: delineating the SIRT3‑driven metabolic and DNA‑repair network. The research team employed CRISPR/Cas9 to generate permanent SIRT3 knockout (KO) in melanoma cell lines. High‑resolution PCR arrays combined with NanoString gene‑expression profiling were used to track transcriptomic changes. The analysis revealed that SIRT3 activates mitochondrial oxidative phosphorylation (OXPHOS) enzymes and exerts upstream control over DNA‑repair pathways that enable cancer cells to survive stress. Conversely, transient siRNA‑mediated SIRT3 inhibition disrupted this regulatory network, leading to a dramatic induction of apoptosis.

Patient‑derived xenograft (PDX) validation: in vivo antitumor efficacy against BRAF‑mutant melanoma. Findings from in vitro experiments were confirmed in the most reliable preclinical platform, PDX models. Mice bearing tumors derived from patients with the most common and resistance‑prone BRAF‑mutant melanoma received an SIRT3‑targeting siRNA‑LNP complex. Metabolic collapse induced by SIRT3 blockade was recapitulated within the tumor microenvironment, and tumor growth rates were markedly suppressed compared with controls. This establishes a novel breakthrough for controlling resistant mutant melanoma.

Targeting mitochondrial metabolic dependency to overcome existing therapy resistance. This study is pivotal because it shifts from conventional inhibition of protein kinase signaling pathways (e.g., MAPK) to directly attacking the mitochondrial energy metabolism and survival infrastructure on which cancer cells depend. SIRT3 inhibition severs the Achilles’ heel of BRAF‑inhibitor‑resistant cells. Moreover, by demonstrating compatibility with LNP or viral vector‑based RNA interference (RNAi) technologies, the work provides strong mechanistic rationale for expanding a programmable, tumor‑specific gene‑knockdown pipeline for next‑generation nucleic‑acid therapeutics.