Supportive agents, such as vitamin B12 (cobalamin, B12) and granulocyte colony-stimulating factor (G-CSF), are widely used during chemotherapy; however, their direct effects on tumor biology are not well understood. We evaluated the impact of pharmacological B12 and G-CSF, alone or in combination with cisplatin, on hormone receptor-positive (MCF-7) and triple-negative (MDA-MB-231) breast cancer cells, conducting in vitro assays of cell viability, cytotoxicity, caspase activation, mitochondrial membrane potential, and cytolytic protein expression. Neither B12 nor G-CSF alone induced cytotoxicity; instead, both promoted proliferation in a dose- and time-dependent manner. When combined with cisplatin, they consistently attenuated drug-induced cytotoxicity, suppressed caspase-3/-8/-9 activation, preserved mitochondrial integrity, and reduced perforin/granzyme expression, exhibiting stronger effects in MCF-7 cells. G-CSF markedly increased proliferation (>130% at 50 ng/mL), while B12 modestly enhanced viability and mitigated cisplatin-induced damage, particularly in triple-negative cells. These findings indicate that B12 and G-CSF can impair cisplatin efficacy by blunting apoptotic signaling and mitochondrial injury in different breast cancer subtypes. These preclinical findings warrant prospective, biomarker-driven in vivo and clinical studies to delineate the clinical contexts in which B12 and G-CSF can be safely integrated into supportive care without compromising antitumor efficacy.

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by dopaminergic neuronal loss, oxidative stress, and mitochondrial dysfunction. Although levodopa (L-Dopa) remains the main symptomatic treatment, prolonged administration can lead to adverse effects. Safranal, a bioactive constituent of Crocus sativus, has antioxidant and anti-apoptotic properties. This study evaluated the neuroprotective potential of L-Dopa and safranal, individually and in combination, in an in vitro cell-culture PD model. Methods: SH-SY5Y human neuroblastoma cells were treated with 6-hydroxydopamine (6-OHDA, 50 µM) to induce cytotoxicity. Cells were pretreated with L-Dopa (5–500 µM) and safranal (1–500 µM and 1–5 mM) for 4 or 24 h. Cell viability was assessed using 3-(4, 5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Mitochondrial membrane potential (MMP), caspase-3/7 activity, and autophagy markers were also evaluated. Synergy was analyzed using Combination Index (CI) analysis. Furthermore, mRNA levels of circadian rhythm associated genes were also evaluated. Results: 6-OHDA significantly impaired cell viability and mitochondrial function. Pretreatment with low doses of L-Dopa and safranal partially improved cell viability and reduced apoptosis and showed a tendency to decrease autophagy-associated marker levels. Higher L-Dopa concentrations caused mild cytotoxicity, while high-dose safranal exhibited pronounced concentration-dependent toxicity. CI analysis confirmed synergistic interaction between both drugs in mitigating 6-OHDA-induced toxicity. Combined treatment markedly improved cell survival preserved mitochondrial function, and reduced caspase-3/7 activity compared with monotherapy. A significant increase in the mRNA levels of Per1, Clock, Bmal1 and Cry1 genes was observed in groups treated with L-Dopa and safranal together. Conclusions: L-Dopa and safranal exerted concentration-dependent neuroprotective effects in SH-SY5Y cells. Their combination enhanced cytoprotection, which was associated with modulation of mitochondrial function, oxidative stress, apoptosis, and autophagy-related responses.