Targeting multiple components of the MAPK pathway can prolong the survival of patients with BRAFV600E melanoma. This approach is not curative, as some BRAF-mutated melanoma cells are intrinsically resistant to MAPK inhibitors (MAPKi). At the systemic level, our knowledge of how signaling pathways underlie drug resistance needs to be further expanded. Here, we have shown that intrinsically resistant BRAF-mutated melanoma cells with a low basal level of mitochondrial biogenesis depend on this process to survive MAPKi. Intrinsically resistant cells exploited an integrated stress response, exhibited an increase in mitochondrial DNA content, and required oxidative phosphorylation to meet their bioenergetic needs. We determined that intrinsically resistant cells rely on the genes encoding TFAM, which controls mitochondrial genome replication and transcription, and TRAP1, which regulates mitochondrial protein folding. Therefore, we targeted mitochondrial biogenesis with a mitochondrium-targeted, small-molecule HSP90 inhibitor (Gamitrinib), which eradicated intrinsically resistant cells and augmented the efficacy of MAPKi by inducing mitochondrial dysfunction and inhibiting tumor bioenergetics. A subset of tumor biopsies from patients with disease progression despite MAPKi treatment showed increased mitochondrial biogenesis and tumor bioenergetics. A subset of acquired drug-resistant melanoma cell lines was sensitive to Gamitrinib. Our study establishes mitochondrial biogenesis, coupled with aberrant tumor bioenergetics, as a potential therapy escape mechanism and paves the way for a rationale-based combinatorial strategy to improve the efficacy of MAPKi.

IMPORTANCE Psoriasis is a chronic inflammatory skin disease associated with increased coronary plaque burden and cardiovascular events. Biologic therapy for psoriasis has been found to be favorably associated with luminal coronary plaque, but it is unclear whether these associations are attributable to direct anti-inflammatory effects on the coronary arteries. OBJECTIVE To investigate the association of biologic therapy with coronary inflammation in patients with psoriasis using the perivascular fat attenuation index (FAI), a novel imaging biomarker that assesses coronary inflammation by mapping spatial changes of perivascular fat composition via coronary computed tomography angiography (CCTA). DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study performed from January 1, 2013, through March 31, 2019, analyzed changes in FAI in patients with moderate to severe psoriasis who underwent CCTA at baseline and at 1 year and were not receiving biologic psoriasis therapy at baseline. EXPOSURES Biologic therapy for psoriasis. MAIN OUTCOMES AND MEASURES Perivascular FAI mapping was performed based on an established method by a reader blinded to patient demographics, visit, and treatment status. RESULTS Of the 134 patients (mean [SD] age, 51.1 [12.1] years; 84 [62.5%] male), most had low cardiovascular risk by traditional risk scores (median 10-year Framingham Risk Score, 3% [interquartile range, 1%-7%]) and moderate to severe skin disease. Of these patients, 82 received biologic psoriasis therapy (anti-tumor necrosis factor α, anti-interleukin [IL] 12/23, or anti-IL-17) for 1 year, and 52 did not receive any biologic therapy and were given topical or light therapy (control group). At baseline, 46 patients (27 in the treated group and 19 in the untreated group) had a focal coronary atherosclerotic plaque. Biologic therapy was associated with a significant decrease in FAI at 1 year (median FAI −71.22 HU [interquartile range (IQR), −75.85 to −68.

In melanoma, therapies with inhibitors to oncogenic BRAFV600E are highly effective but responses are often short-lived due to the emergence of drug-resistant tumor subpopulations. We describe here a mechanism of acquired drug resistance through the tumor microenvironment, which is mediated by human tumor-associated B cells. Human melanoma cells constitutively produce the growth factor FGF-2, which activates tumor-infiltrating B cells to produce the growth factor IGF-1. B-cell-derived IGF-1 is critical for resistance of melanomas to BRAF and MEK inhibitors due to emergence of heterogeneous subpopulations and activation of FGFR-3. Consistently, resistance of melanomas to BRAF and/or MEK inhibitors is associated with increased CD20 and IGF-1 transcript levels in tumors and IGF-1 expression in tumor-associated B cells. Furthermore, first clinical data from a pilot trial in therapy-resistant metastatic melanoma patients show anti-tumor activity through B-cell depletion by anti-CD20 antibody. Our findings establish a mechanism of acquired therapy resistance through tumor-associated B cells with important clinical implications.

Background: Lipid-rich necrotic core (LRNC), a high-risk coronary plaque feature assessed by coronary computed tomography angiography, is associated with increased risk of future cardiovascular events in patients with subclinical, nonobstructive coronary artery disease. Psoriasis is a chronic inflammatory condition that is associated with increased prevalence of high-risk coronary plaque and risk of cardiovascular events. This study characterized LRNC in psoriasis and how LRNC modulates in response to biologic therapy. Methods: Consecutive biologic naïve psoriasis patients (n=209) underwent coronary computed tomography angiography at baseline and 1-year to assess changes in LRNC using a novel histopathologically validated software (vascuCAP Elucid Bioimaging, Boston, MA) before and after biologic therapy over 1 year. Results: Study participants were middle-aged, predominantly male with similar cardiometabolic and psoriasis status between treatment groups. In all participants at baseline, LRNC was associated with Framingham risk score (β [standardized β]=0.12 [95% CI, 0.00–0.15]; P =0.045), and psoriasis severity (β=0.13 [95% CI, 0.01–0.26]; P =0.029). At 1-year, participants receiving biologic therapy had a reduction in LRNC (mm 2 ; 3.12 [1.99–4.66] versus 2.97 [1.84–4.35]; P =0.028), while those who did not receive biologic therapy over 1 year demonstrated no significant change with nominally higher LRNC (3.12 [1.82–4.60] versus 3.34 [2.04–4.74]; P =0.06). The change in LRNC was significant compared with that of the nonbiologic treated group (ΔLRNC, −0.22 mm 2 versus 0.14 mm 2 , P =0.004) and remained significant after adjusting for cardiovascular risk factors and psoriasis severity (β=−0.09 [95% CI, −0.01 to −0.18]; P =0.033). Conclusions: LRNC was associated with psoriasis severity and cardiovascular risk factors in psoriasis. Additionally, there was favorable modification of LRNC in those on biologic therapy. This study provides evidence of potential reduction in LRNC with treatment of systemic inflammation. Larger, longer follow-up prospective studies should be conducted to understand how changes in LRNC may translate into a reduction in future cardiovascular events in psoriasis.