Search Results (256)

Two-pore channel 2 (TPC2) is a member of the endolysosomal ion channel family, playing critical roles in intracellular calcium signaling and endomembrane dynamics. This review provides an in-depth analysis of TPC2, covering its structural and functional properties, physiological roles, and involvement in human diseases. We discuss current experimental approaches to studying TPC2, including heterologous expression in plant vacuoles and computational modeling strategies. Particular emphasis is placed on the structural determinants of ion permeation, with a focus on the selectivity filter and the central cavity’s influence on channel kinetics. Furthermore, we explore emerging roles of TPC2 in viral infections, particularly SARS-CoV-2, and in cancer, including melanoma progression and neoangiogenesis. The inhibitory potential of natural compounds, such as naringenin, is also examined. By offering a comprehensive overview of current knowledge and methodologies, this review underscores the potential of TPC2 as a promising pharmacological target in both infectious and neoplastic diseases. Full article

Background/Objectives: The interaction between brain-metastasizing melanoma cells and surrounding microglia shapes the immune tumor microenvironment and influences tumor progression. Gene expression analysis revealed that sphingosine-1-phosphate receptor 1 (S1PR1), encoding the S1P1 receptor, is upregulated in microglia upon interaction with melanoma cells. Here, we investigated the functions of S1P1 in microglia and its contribution to melanoma–microglia crosstalk. Methods: We examined the effects of S1P1 inhibition on microglia and four brain-metastasizing human melanoma cell lines in monocultures and co-cultures using the selective S1P1 antagonist NIBR0213 and S1PR1 gene knockdown. Results: We found that melanoma-secreted IL-6 upregulated S1PR1 expression in microglia. S1P1 inhibition increased expression of CD32, CD150, and CD163 in microglia; however, CD150 and CD163 upregulation was abolished in the presence of melanoma cells. S1P1 inhibition downregulated immunosuppressive and anti-inflammatory factors in microglia, including CD274, SOCS3, TGFBR1, TGFBR2, and JunB, promoting a pro-inflammatory phenotype. It also reduced viability of both melanoma and microglia cells, inducing apoptosis in melanoma-associated microglia, possibly via downregulation of CH25H, an upstream regulator of SREBPs. In co-cultures, melanoma cells were more sensitive than microglia to NIBR0213-induced growth arrest. In 3D spheroid cultures, NIBR0213 delayed melanoma–microglia aggregation. Combined treatment with the BRAF inhibitor Vemurafenib and NIBR0213 enhanced Vemurafenib efficacy in three of four melanoma lines. Conclusions: S1P1 contributes to the immunosuppressive phenotype of microglia. Inhibiting the S1P/S1P1 axis impairs viability and crosstalk between melanoma cells and tumor-activated microglia, offering a potential therapeutic strategy for melanoma brain metastases. Full article

DROSHA protein is widely known for its essential role in the microRNA (miRNA/miR) biogenesis pathway where, together with its co-factor DGCR8, it forms the “Microprocessor” complex and catalyzes the primary miRNA (pri-miRNA) processing in the nucleus. Nevertheless, DROSHA also seems to participate in several miRNA-independent cellular mechanisms, such as transcriptional regulation, RNA processing and genome integrity maintenance. Hence, the present study aims to further investigate novel miRNA-independent activities of DROSHA protein, with potentially regulatory roles in the oncogenesis of human cancer cells. Our results reveal a new, strong profile of microprocessor-independent DROSHA localization at the Golgi apparatus in several human cancer cell lines of different tissue origin, with hepatic carcinoma, thyroid cancer, urothelial bladder cancer, colon carcinoma and melanoma being the cellular model systems herein examined. Notably, oncogenic activity, malignancy grade and metastatic capacity are shown to be strongly associated with DROSHA’s compartmentalization at Golgi, a phenotype that does not seem to rely on p53 protein’s functionality. Taken together, through employment of advanced confocal laser scanning microscopy (CLSM) and molecular modeling, we herein unveil the ability of DROSHA, but not AGO2 and DICER, to reside at Golgi, where DROSHA can physically interact with the GM130 Golgi-specific component, thus indicating DROSHA’s engagement in non-canonical and miRNA-independent—but also Golgi apparatus-dependent—novel mechanisms that can be tightly coupled with malignancy dynamics and beneficially utilized as potential biomarkers and therapeutic targets for human cancer. Full article

Vascular mimicry (VM) refers to the formation of vessel-like structures by tumor cells independent of endothelial cells. These VM channels connect to the host’s vascular network and are associated with aggressive tumors and poor patient prognosis. Most VM research has been conducted on melanoma, relying on patient-derived and mouse cell lines. In other solid tumors, VM studies rely on human cell lines, which have certain limitations for in vivo studies. Specifically, most in vivo VM research involving human cells uses subcutaneous mouse models that fail to recapitulate organ-specific tumor microenvironments. As the microenvironment is an essential driver of tumor vascularization, including VM, murine cell lines could facilitate VM investigations in syngeneic mouse models. Here, we present CT26 and KPC, well-characterized murine colorectal and pancreatic cancer cell lines, as cell models for VM investigations. Using in vitro cell-based assays, we demonstrate that CT26 and KPC undergo VM, a cell-intrinsic process that is enhanced by serum deprivation and exposure to hypoxia and is independent of tumor-secreted growth factors. Additionally, we demonstrate the importance of YAP/TAZ signaling in VM formation, as inhibition at non-cytotoxic concentrations attenuated VM formation. Remarkably, CA3, the most potent of the two inhibitors, significantly reduced cell proliferation in both cell lines at the IC₅₀ concentration. This reduction in cell proliferation was associated with the induction of apoptosis in CT26 cells and changes in the cell cycle in both CT26 and KPC cells. Finally, dual YAP/TAZ knockdown in both cell lines significantly abrogated VM formation, validating our initial findings using inhibitors. These results show that CT26 and KPC cells undergo VM, and given their extensive use in cancer research, can be used to investigate VM in vivo using syngeneic models. Full article

Skin cancer is the most common cancer worldwide. The incidence of skin cancer has been increasing worldwide. Nearly 75% of all skin cancers are basal cell carcinomas (BCC), cutaneous squamous cell carcinoma (cSCC) represents approximately 20%, and those remaining are melanomas (4%) or other rare tumors (1%). Given the high cure rates and the ability to histologically confirm tumor clearance, surgical therapy is the gold standard for the treatment of skin cancer. Conventional surgery is the most employed technique for the removal of non-melanoma skin cancer (NMSCs). Mohs Micrographic Surgery (MMS) is the most precise surgical method for the treatment of non-melanoma skin cancer, allowing for 100% margin evaluation, being the gold-standard method for surgical treatment of non-melanoma skin cancer. Whenever it is possible to obtain wide margins (4 to 6 mm), cure rates vary from 70% to 99%. Imiquimod, a synthetic imidazoquinolinone amine, is a topical immune response modifier approved by the U.S. Food and Drug Administration (FDA) for the treatment of external anogenital warts, actinic keratosis (AK), and superficial basal cell carcinoma (sBCC). The efficacy of imiquimod is primarily attributed to its ability to modulate both innate and adaptive immune responses, as well as its direct effects on cancer cells. Imiquimod exerts its immunomodulatory effects by activating Toll-like receptors 7 and 8 (TLR7/8) on various immune cells, including dendritic cells, macrophages, and natural killer (NK) cells. Upon binding to these receptors, imiquimod triggers the MyD88-dependent signaling pathway, leading to the activation of nuclear factor kappa B (NF-κB) and interferon regulatory factors (IRFs). This cascade leads to the production of pro-inflammatory cytokines, including interferon-alpha (IFN-α), tumor necrosis factor-alpha (TNF-α), interleukin-12 (IL-12), and interleukin-6 (IL-6). These cytokines enhance local inflammation, recruit additional immune cells to the tumor site, and stimulate antigen presentation, thereby promoting an anti-tumor immune response. Radiation therapy (RTh) may be employed as a primary treatment to BCC. It may also be employed as an adjuvant treatment to surgery for SCC and aggressive subtypes of BCC. RTh triggers both direct and indirect DNA damage on cancer cells and generates reactive oxygen species (ROS) within cells. ROS trigger oxidative damage to DNA, proteins, and lipids, exacerbating the cellular stress and contributing to tumor cell death. Recently, immunotherapy emerged as a revolutionary treatment for all stages of SCC. Cemiplimab is a human programmed cell death 1 (PD-1)-blocking antibody that triggers a response to over 50% of patients with locally advanced and metastatic SCC. A randomized clinical trial (RCT) published in 2022 revealed that cemiplimab was highly effective in the neoadjuvant treatment of large SCCs. The drug promoted a significant tumor size decrease, enabling organ-sparing operations and a much better cosmetic effect. A few months ago, a RCT of cemiplimab on adjuvant therapy for locally aggressive SCC was published. Interestingly, cemiplimab was administered to patients with local or regional cutaneous squamous cell carcinoma after surgical resection and postoperative radiotherapy, at high risk for recurrence owing to nodal features, revealed that cemiplimab led to much lower risks both of locoregional recurrence and distant recurrence. Full article

Compound T1089—a novel nitrogen mustard based on an indole-3-carboxylic acid derivative (ICAD)—has been synthesized. The ICAD used as the basis for T1089 is a TLR agonist capable of activating an antitumor immune response. This study describes the synthesis method and presents the results of preliminary investigations of this compound. This research included an assessment of acute toxicity in mice, in vivo clastogenic activity evaluated via the bone marrow chromosome aberration (BMCA) test in mice, in vitro cytotoxicity determined by the MTT assay against human lung carcinoma A549 cells, and in vivo antitumor effects (ATEs) in models of conventional chemotherapy (CCT) of solid tumors in mice. The bifunctional alkylating agent cyclophosphamide (CPA) was used as a reference drug. Toxicological studies revealed that T1089 belongs to toxicity class III (moderately toxic), with acute toxicity values (LD₁₆ and LD₅₀) in mice following intraperitoneal (i.p.) administration being 191 and 202 mg/kg, respectively. The alkylating activity and clastogenic potential of T1089 were demonstrated by its effects in the BMCA test, which were comparable to those of CPA. A single i.p. administration of CPA and T1089 at a dose of 0.064 mmol/kg induced similar stimulation of structural mutagenesis associated with DNA strand breaks. The frequency of karyocytes with aberrations increased 20-fold compared to the control, primarily due to a rise in chromatid breaks and fragments, and to a lesser extent, due to an increase in exchange-type aberrations. In vitro cytotoxicity studies indicated differences in the mechanisms of alkylating activity between CPA and T1089. According to the MTT assay, the cytotoxic effects of CPA were observed only at concentrations exceeding 2 mM (IC₅₀ = 4.2 ± 0.3 mM), corresponding to lethal in vivo doses, which is expected since the formation of CPA’s alkylating metabolite requires hepatic microsomal enzymes. In contrast, significant cytotoxic effects of T1089 were observed at much lower concentrations (15–50 μM, IC₅₀ = 33.4 ± 1.3 μM), corresponding to safe in vivo doses. Differences were also observed in the in vivo ATEs of CPA and T1089 in the Ehrlich solid carcinoma (ESC) CCT model. Following seven i.p. administrations at 48 h intervals (33 mg/kg), both compounds exhibited increasing toxicity, manifested as cumulative body weight loss in treated mice. However, despite the aggressive CCT regimen, ESC showed low sensitivity to CPA. The ATE of CPA developed slowly, reaching a significant level only after four injections, and even after seven administrations, tumor inhibition (TI) did not exceed 30%. In contrast, ESC was significantly more sensitive to T1089 under the same CCT conditions. The ATE of T1089 exhibited a cumulative pattern but developed more rapidly and to a greater extent. A significant antitumor effect was observed after just two injections, with maximal efficacy (TI = 53%) achieved after four injections and sustained until the end of the observation period. A high ATE of T1089 was also observed in the B-16 melanoma CCT model. Following six i.p. administrations at 48 h intervals (28 mg/kg), T1089 treatment was associated with minimal toxicity. Despite this mild CCT regimen, melanoma exhibited high sensitivity to T1089. Maximal ATE (TI = 56%) was achieved after two injections, and subsequent administrations maintained a consistently high efficacy (TI = 52–55%) until the end of the study. In summary, preliminary findings demonstrate that T1089 possesses alkylating activity characteristic of bifunctional agents, accompanied by high in vitro cytotoxicity and in vivo ATEs in CCT models (at high doses). Given that the ICAD used as the basis for T1089 is a TLR agonist capable of stimulating antitumor immunity, T1089 can be considered a dual-action alkylating agent with combined antitumor effects. These results justify further investigation of T1089 in conventional and metronomic chemotherapy regimens, particularly in combination with immune checkpoint inhibitors and antitumor vaccines. Full article

Derivatives of natural amino acids are selectively absorbed by many types of tumour cells. This makes the use of amino acids, especially polyfunctional ones, attractive as a basis in the design of low-toxicity agents for targeted boron delivery for boron neutron capture therapy (BNCT) of tumours. We synthesized a series of new (S)-ornithine and (S)-lysine derivatives containing a 7,8-dicarba-nido-undecaborane (nido-carborane) residue attached to the amino group in the side chain or alpha position. The MTT assay demonstrated moderate cytotoxicity of the lysine and ornithine derivatives containing a nido-carborane residue in the side chain. It has been found that sodium salt of N^ε-(nido-carboran-7-yl)acetyl-(S)-lysine is capable of accumulation by MDA-MB-231 (human breast carcinoma) and SK-Mel 28 (human melanoma) cell lines, providing a boron concentration of up to 0.67 µg/10⁶ cells in in vitro experiments. This (S)-lysine derivative containing a nido-carborane residue in the side chain can be considered as a promising compound for in-depth study in vivo experiments aimed at designing an efficient boron delivery agent for BNCT. Full article

Doxorubicin (Dox) is not a first-line treatment for melanoma due to limited antitumor efficacy and dose-dependent cardiotoxicity. However, sublethal doses may trigger adaptive cellular responses that influence tumor progression and systemic toxicity. Small extracellular vesicles (EVs) are key mediators of intercellular communication and can carry bioactive molecules that modulate both the tumor microenvironment and distant tissues. This study investigates how sublethal Dox exposure alters EV biogenesis and cargo in A375 melanoma cells and explores the potential implications for cardiovascular function. We treated human A375 melanoma cells with 10 nM dox for 96 h. EVs were isolated using differential ultracentrifugation and size exclusion chromatography. Vesicle characterization included Immunocytochemistry for CD63, CD81, CD9, Rab7 and TSG101, scanning electron microscopy (SEM) Nanoparticle Tracking Analysis (NTA), and Western blotting for CD81 and CytC. We analyzed cytokine content using cytokine membrane arrays. Guinea pig cardiomyocytes were exposed to the isolated vesicles, and mitochondrial activity was evaluated using the MTT assay. Statistical analysis included t-tests, ANOVA, Cohen’s d, and R² and η². Dox exposure significantly increased EV production (13.6-fold; p = 0.000014) and shifted vesicle size distribution. CD81 expression was significantly upregulated (p = 0.0083), and SEM (microscopy) confirmed enhanced vesiculation. EVs from treated cells were enriched in TGF-β (p = 0.0134), VEGF, CXCL1, CXCL12, CCL5, IL-3, IL-4, IL-10, Galectin-3, and KITLG. Cardiomyocytes exposed to these vesicles showed a 2.3-fold reduction in mitochondrial activity (p = 0.0021), an effect absent when vesicles were removed. Bioinformatic analysis linked EV cargo to pathways involved in cardiac hypertrophy, inflammation, and fibrosis. As conclusion, sublethal Doxorubicin reprograms melanoma-derived EVs by enhancing their production and enriching their cargo with profibrotic and immunomodulatory mediators. These vesicles may contribute to tumor progression and cardiovascular physiopathology, suggesting that targeting EVs could improve therapeutic outcomes in cancer and cardiovascular disease. Full article

Cancer is still the world’s most prevalent cause of death, and the limited efficacy of current treatments highlights the requirement for new therapeutic approaches. In this study, neodymium (Nd)-doped cobalt ferrite (CoFe_2₋zNd_zO₄, z = 0; 0.01; 0.02; 0.03; 0.05; 0.1) nanoparticles (Nd0-Nd5) were synthesized via the combustion method. The structural, morphological, and magnetic properties were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and scanning transmission electron microscopy (STEM) analysis. The synthesized compounds demonstrated single-phase spinel structures, with morphological differences observed between undoped and Nd-doped samples. The biological activity of the nanoparticles was evaluated on immortalized human keratinocytes (HaCaT) and on cancer cell lines: melanoma (A375), breast adenocarcinoma (MCF-7), and pancreatic carcinoma (PANC-1). The cytotoxic effects of Nd0-Nd5 (50–1000 μg∙mL⁻¹) were assessed through Alamar Blue and lactate dehydrogenase (LDH) release assays. The results indicated a dose-dependent cytotoxic effect in cancer cell lines. Changes in cell morphology, suggesting the induction of the apoptotic processes, were observed through immunofluorescence staining of F-actin and nuclei. These findings highlight the potential of Nd-doped cobalt ferrite nanoparticles as selective anticancer agents, warranting further investigation to fully elucidate their mechanisms of action and therapeutic applicability. Full article

Background/Objectives: Cancer is one of the leading causes of death worldwide, and skin cancer is especially prevalent and lethal in Brazil. Despite advancements in treatment, there is still a need for new anticancer agents that are effective, selective, and less toxic. This study aimed to evaluate the cytotoxic and therapeutic potential of the peptide PEPAD. Methods: The cytotoxicity of PEPAD was assessed by MTT assay in murine melanoma (B16F10-Nex2), human melanoma (SK-MEL-28), breast (MCF-7), and cervical (HeLa) cancer cell lines. Selectivity was evaluated in healthy cells (RAW 264.7 and FN1). Morphological changes were analyzed by microscopy. Cell migration was assessed using scratch assays. Apoptotic features were evaluated using MitoTracker Deep Red, NucBlue, CaspACETM labeling, and flow cytometry. Immunogenic cell death was investigated by calreticulin and HMGB1 release. Molecular dynamics simulations explored peptide structure and interaction with lipid membranes. Results: PEPAD showed IC₅₀ values of 7.4 µM and 18 µM in B16F10-Nex2 and SK-MEL-28 cells, respectively, and >60 µM in MCF-7 and HeLa cells. Low toxicity was observed in healthy cells (IC₅₀ > 56 µM), indicating high selectivity. Apoptotic morphology and reduced cell migration were observed. Flow cytometry and fluorescence probes confirmed apoptosis and mitochondrial swelling. Calreticulin and HMGB1 release indicated immunogenic cell death. Simulations showed that PEPAD maintains a stable α-helical conformation and interacts with membranes. Conclusions: These findings highlight PEPAD’s selective cytotoxicity and its potential as an anticancer agent with apoptotic and immunogenic properties, making it a promising candidate for therapeutic development. Full article

C-C motif chemokine receptor-like 2 (CCRL2) is an atypical chemokine receptor (ACKR) that binds chemerin with high affinity but lacks classical G protein-coupled signaling. Instead, it functions as a non-signaling presenter of chemerin to CMKLR1-expressing cells, modulating antitumor immunity. CCRL2 is highly expressed in the tumor microenvironment and various human cancers, and its expression has been linked to delayed tumor growth in mouse models, primarily through the chemerin/CMKLR1 axis. While CCRL2’s role in immune surveillance is well established, its tumor cell-intrinsic functions remain less clear. Here, we investigated the impact of CCRL2 overexpression and knockout on tumor cell behavior in vitro. Although CCRL2 did not affect proliferation, migration, or clonogenicity in B16F0 melanoma and LLC cells, it significantly influenced spheroid morphology in B16F0 cells. Transcriptomic analysis revealed that CCRL2 modulates innate immune signaling pathways, including TLR4 and IFN-γ/STAT1, with context-dependent downstream effects. These findings suggest that CCRL2 shapes tumor architecture by rewiring inflammatory signaling networks in a cell-intrinsic manner. Further studies in other cancer types and cell models are needed to determine whether CCRL2’s regulatory role is broadly conserved and to explore its potential as a therapeutic target in solid tumors. Full article

Background: The increased incidence of malignant melanoma is observed in patients with Parkinson’s disease. Methods: The anti-proliferative effects of carbidopa and rasagiline on four human malignant melanoma cell lines (A375, SK-MEL28, FM55P and FM55M2) were determined in MTT assay. The interaction profiles of rasagiline in combinations with cisplatin (CDDP) and mitoxantrone (MTX) in four human melanoma cell lines (A375, SK-MEL28, FM55P and FM55M2) were assessed by means of the isobolographic analysis in the MTT test; Results: Rasagiline, but not carbidopa, produced clear-cut anti-proliferative effects on various melanoma cell lines. The median inhibitory concentrations (IC₅₀ values) of rasagiline in the MTT were 280.69 µM for A375, 402.89 µM for SK-MEL28, 349.44 µM for FM55P, and 117.45 µM for FM55M2, respectively. The experimentally-derived selectivity index for rasagiline ranged from 8.22 to 28.18. Flow cytometry assay revealed, in two melanoma cell lines (FM55P and A375), a significant increase in the number of cells in the G0/G1 (up to 76.48% and 75.46% for cell lines, respectively), accompanied by a decrease in the percentage of cells in the S phase (decrease to 9.91% and 10.83% for cell lines, respectively), which may indicate potential cytostatic properties of rasagiline. The combinations of rasagiline with CDDP (at the fixed-ratio of 1:1) exerted either antagonistic interactions (p < 0.05) in the A375 and SK-MEL28, or additive interactions, with a tendency toward antagonism in the FM55P and FM55M2 cell lines in the MTT test. In contrast, the combinations of rasagiline with MTX (ratio of 1:1) produced either synergistic interaction (p < 0.05) in the FM55P cell line or additive interactions with a tendency toward synergy in the FM55M2, SK-MEL28, and A375 cell lines in the MTT test. Conclusions: Rasagiline combined with MTX exerted the most desirable synergistic interactions in relation to the anti-proliferative effects in four malignant melanoma cell lines, as assessed isobolographically. In contrast, rasagiline should not be combined with CDDP during the treatment of malignant melanoma due to the antagonistic interactions in the MTT assay. Full article

Two triterpene saponins, hederagenin glucosides, including a novel monodesmoside: 3-O-β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl] hederagenin (compound 1), were isolated from the fruits of Oxybasis rubra (L.) S.Fuentes, Uotila & Borsh (Amaranthaceae). These compounds, together with hederagenin itself (compound 4) and a commercially available 28-O-β-D-glucopyranosyl hederagenin ester (compound 3), were evaluated for cytotoxicity and selectivity across a wide panel of human cancer cell lines (skin, prostate, gastrointestinal, thyroid, and lung). All four compounds exhibited dose- and time-dependent effects, with varying potency depending on the specific cancer type. The isolated bidesmosidic saponin (3-O-β-D-glucopyranosyl(1→3)-β-D-glucopyranosyl] hederagenin 28-O-β-D-glucopyranosyl ester—compound 2) showed the strongest activity and selectivity, with an IC₅₀ = 6.52 μg/mL after 48 h incubation against WM793 melanoma, and almost no effect on normal HaCaT skin cells (IC₅₀ = 39.94 μg/mL). Multivariate analysis of the obtained data using principal component analysis (PCA) and hierarchical cluster analysis (HCA) supported the assumption that cytotoxicity is influenced by the type of compound, its concentration, and the intrinsic sensitivity of the cell line. Structure-activity observations between closely related hederagenin derivatives are also briefly presented. Full article

Background: We have previously shown the remarkable impact of a single infusion of supercharged NK cells (sNK) in preventing and eliminating oral, pancreatic, and uterine cancers implanted in humanized BLT (hu-BLT) mice. Objective: In this report, we extended the studies to melanoma tumors to observe whether there were differences in response to sNK cells. Methods: We investigated the safety and tissue biodistribution profile of sNK cells in hu-BLT mice. This included the effect of sNK cell therapy on the peripheral blood-derived PBMCs, bone marrow, and spleen of hu-BLT mice. Results: Our investigation showed promising outcomes, as sNK cell infusions effectively inhibited melanoma tumor growth in hu-BLT mice. These potent cells not only traversed through the peripheral blood, spleen, and bone marrow but also infiltrated the tumor site, triggering in vivo differentiation of melanoma tumors. Moreover, the infusion of sNK cells increased the percentages of NK cells in the peripheral blood of hu-BLT mice, restoring cytotoxicity and IFN-γ secretion within the peripheral blood, spleen, and bone marrow of melanoma-bearing mice. Conclusions: This therapeutic approach not only reversed tumor progression but also revitalized the functionality of endogenous NK cells, potentially reversing the immunosuppressive effects induced by tumor cells in cancer patients. Full article

Skin cancer, including melanoma and non-melanoma cancers (basal and squamous cell carcinomas), is the most common type of cancer. UV radiation, family history, and genetic predisposition are the main risk factors. Although surgical excision is the standard treatment, essential oils are attracting growing interest for their anti-cancer effects. This study tested the effects of Juniperus excelsa M. Bieb. (Cupressaceae), Lavandula vera DC. (Lamiaceae), and Salvia fruticosa (Mill). (Lamiaceae) essential oils extracted from Middle Eastern medicinal plants on HaCaT (normal), A5 (benign), and II4 (low-grade malignant) keratinocytes. Essential oils were extracted from Juniperus excelsa, Lavandula vera, and Salvia libanotica using steam distillation and then were chemically analyzed. The oils were sterilized, dissolved in DMSO, and prepared at concentrations of 0.75, 0.5, and 0.25 mg/mL. Human keratinocyte (HaCaT), benign (A5), and malignant (II4) cell lines were cultured in DMEM and treated with the essential oils for 24 or 48 h. Cell viability was assessed using the Trypan Blue Exclusion Test, while cell proliferation was evaluated using the MTT assay. Statistical analysis was performed using ANOVA with appropriate post hoc tests, considering p < 0.05 as significant. The results show that J. excelsa is cytotoxic but lacks selectivity, limiting its efficacy. In contrast, L. vera and S. fruticosa preferentially target malignant cells, particularly at low concentrations, while sparing normal cells. These oils have dose-dependent anticancer effects, with L. vera efficacy increasing as the concentration increases. In conclusion, L. vera and S. fruticosa are promising candidates for the treatment of skin cancer, although further in vivo studies are required. Full article