Change in Anticancer Drug Sensitivity During Neuronal Differentiation of PC12 Cells

Re-Evaluation of Chemotherapeutic Potential of Pyoktanin Blue

Background: Pyoktanin blue (PB) is used for staining tissues and cells, and it is applied in photodynamic therapy due to its potent bactericidal activity. However, clinical application of PB as an antiviral and antitumor agent has been limited due to its potent toxicity. For clinical application, the antitumor and antiviral activity as well as the neurotoxicity of PB were re-evaluated with a chemotherapeutic index. Methods: Tumor-specificity (TS) was determined by the ratio of CC₅₀ against normal oral cells/oral squamous cell carcinoma (OSCC); neurotoxicity by that of normal oral/neuronal cells; antiviral activity by that of mock-infected/virus-infected cells; and potency-selectivity expression (PSE) by dividing TS by CC₅₀ (OSCC). Results: Antitumor activity of PB (assessed by TS and PSE) was comparable with that of DXR and much higher than that of 5-FU and melphalan. PB induced caspase-3 activation and subG1 cell accumulation in an OSCC cell line (Ca9-22). PB and anticancer drugs showed comparable cytotoxicity against both neuronal cells and OSCC cell lines. PB showed no detectable anti-HIV/HSV activity, in contrast to reverse transferase inhibitors, sulfated glucans, and alkaline extract of leaves of S.P. Conclusions: PB showed first-class anticancer activity and neurotoxicity, suggesting the importance of establishing the safe treatment schedule.

PC12 and THP-1 Cell Lines as Neuronal and Microglia Model in Neurobiological Research

Models based on cell cultures have become a useful tool in modern scientific research. Since primary cell lines are difficult to obtain and handle, neoplasm-derived lines like PC12 and THP-1 offer a cheap and flexible solution for neurobiological studies but require prior differentiation to serve as a neuronal or microglia model. PC12 cells constitute a suitable research model only after differentiation by incubation with nerve growth factor (NGF) and THP-1 cells after administering a differentiation factor such as phorbol 12-myristate-13-acetate (PMA). Still, quite often, studies are performed on these cancer cells without differentiation. The study aimed to assess the impact of PC12 or THP-1 cell differentiation on sensitivity to harmful factors such as Aβ25-35 (0.001–5 µM) (considered as one of the major detrimental factors in the pathophysiology of Alzheimer’s disease) or lipopolysaccharide (1–100 µM) (LPS; a pro-inflammatory factor of bacterial origin). Results showed that in most of the tests performed, the response of PC12 and THP-1 cells induced to differentiation varied significantly from the effect in undifferentiated cells. In general, differentiated cells showed greater sensitivity to harmful factors in terms of metabolic activity and DNA damage, while in the case of the free radicals, the results were heterogeneous. Obtained data emphasize the importance of proper differentiation of cell lines of neoplastic origin in neurobiological research and standardization of cell culture handling protocols to ensure reliable results.

Trigonelline-loaded chitosan nanoparticles prompted antitumor activity on glioma cells and biocompatibility with pheochromocytoma cells

Trigonelline-loaded water-soluble chitosan nanoparticles (Trigo-WSCS NPs) were prepared for the treatment of glioblastoma (targeting C6 glioma cells) and also evaluated its biocompatibility with rat adrenal pheochromocytoma cells (PC12 cells). WSCS-Trigo NPs characteristics were determined using UV-Visible spectrophotometer, FTIR, XRD, TEM, DLS, and Zeta potential. Trigo-WSCS NPs were noted to have a spherical shape, with an average size of 356 nm. Trigo-WSCS NPs zeta potential was 30.9 mv, which expresses its good stability. The WSCS-Trigo NPs considerably inhibited the growth of rat C6 glioma cells and exhibited an IC₅₀ concentration of 34 μg/mL. Further, Trigo-WSCS NPs were biocompatible with PC12 cells in terms of enhancing neurite growth and differentiation. In conclusion, Trigo-WSCS NPs could act as an antitumor drug for the treatment of glioblastoma as suggested by the in vitro studies.

PC12 Cell Line: Cell Types, Coating of Culture Vessels, Differentiation and Other Culture Conditions

The PC12 cell line is one of the most commonly used in neuroscience research, including studies on neurotoxicity, neuroprotection, neurosecretion, neuroinflammation, and synaptogenesis. Two types of this line are available in the ATCC collection: traditional PC12 cells grown in suspension and well-attached adherent phenotype. PC12 cells grown in suspension tend to aggregate and adhere poorly to non-coated surfaces. Therefore, it is necessary to modify the surface of culture vessels. This paper aims to characterise the use of two distinct variants of PC12 cells as well as describe their differentiation and neuronal outgrowth with diverse NGF concentrations (rat or human origin) on various surfaces. In our study, we evaluated cell morphology, neurite length, density and outgrowth (measured spectrofluorimetrically), and expression of neuronal biomarkers (doublecortin and NeuN). We found that the collagen coating was the most versatile method of surface modification for both cell lines. For adherent cells, the coating was definitely less important, and the poly-d-lysine surface was as good as collagen. We also demonstrated that the concentration of NGF is of great importance for the degree of differentiation of cells. For suspension cells, we achieved the best neuronal characteristics (length and density of neurites) after 14 days of incubation with 100 ng/mL NGF (change every 48 h), while for adherent cells after 3-5 days, after which they began to proliferate. In the PC12 cell line, doublecortin (DCX) expression in the cytoplasm and NeuN in the cell nucleus were found. In turn, in the PC12 Adh line, DCX was not expressed, and NeuN expression was located in the entire cell (both in the nucleus and cytoplasm). Only the traditional PC12 line grown in suspension after differentiation with NGF should be used for neurobiological studies, especially until the role of the NeuN protein, whose expression has also been noted in the cytoplasm of adherent cells, is well understood.

Change in Amino Acid Pools During Neuronal Differentiation of PC12 Cells

BACKGROUND/AIM

Although rat PC12 cells are a well-established model to investigate neuronal differentiation, survival and function, the reports of differentiation-associated changes in the intracellular amino acid pools of neurotransmitters have been limited. In this study, possible changes in the intracellular amino acid pools were investigated during nerve growth factor (NGF)-induced differentiation of PC12 cells.

MATERIALS AND METHODS

Rat PC12 cells were induced to differentiate into neuronal cells by 50 ng/ml NGF in serum-free Dulbecco's Modified Eagle's medium, followed by the addition of fresh NGF-containing medium at day 3, without medium change. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Intracellular amino acids were extracted by 5%trichloroacetic acid and quantified by amino acid analyzer.

RESULTS

Differentiated PC12 cells showed high concentrations of excitatory neurotransmitters (glutamic acid and aspartic acid) and glutamine (energy supply). In contrast, urea and taurine levels declined with the progression of neuronal differentiation. Exogenous addition of taurine, urea, and L- and D- aspartic acid showed little or no effect on supporting viability of PC12 cells cultured in serum-free medium.

CONCLUSION

The present study demonstrated dramatic changes in the composition of intracellular amino acids during neuronal differentiation.

Search of Neuroprotective Polyphenols Using the "Overlay" Isolation Method

Previous studies of the neuroprotective activity of polyphenols have used ununiform culture systems, making it difficult to compare their neuroprotective potency. We have established a new and simple method for preparing differentiated PC12 cells by removing the toxic coating step. Cells were induced to differentiate with the nerve growth factor (NGF) in a serum-free medium, without a medium change, but with a one-time overlay supplementation of NGF. The optimal inoculation density of the cells was 6–12 × 10³ cells/cm², and the presence of serum inhibited the differentiation. Neuroprotective activity could be quantified by the specific index (SI) value, that is, the ratio of the 50% cytotoxic concentration to the 50% effective concentration. Alkaline extract from the leaves of Sasa senanensis Rehder (SE), having had hormetic growth stimulation, showed the highest SI value, followed by epigallocatechin gallate. The SI value of curcumin and resveratrol was much lower. This simple overly method, that can prepare massive differentiated neuronal cells, may be applicable for the study of the differentiation-associated changes in intracellular metabolites, and the interaction between neuronal cells and physiological factors.