O-342

The O-342 cell line is derived from a rat ovarian tumor and is widely used in cancer research, particularly in studies focusing on ovarian cancer and chemotherapy resistance. This cell line is characterized by its ability to grow in a monolayer and enter log-phase growth approximately 24 hours after seeding, with a cell population doubling time of about 24 hours. The O-342 cell line serves as the parental line for several sublines, including the cisplatin-resistant O-342/DDP subline, which was developed through the stepwise increase of cisplatin concentrations in vitro.

O-342 cells exhibit heteroploidy in their chromosomal structure, which contrasts with the near-diploid karyotype observed in the O-342/DDP subline. This karyotypic change is indicative of the selective pressure exerted by continuous cisplatin exposure, which eliminates the cisplatin-sensitive subpopulation, resulting in the predominance of resistant cells. Biochemical analyses have shown that the O-342/DDP cells possess a 33-fold increase in resistance to cisplatin compared to the parental O-342 cells. This resistance is reflected in the ID50 values, with the O-342/DDP cells having an ID50 of 33 μM compared to 1 μM in the O-342 cells.

Further studies have revealed that the O-342/DDP cells have significantly higher levels of intracellular total glutathione (GSH+GSSG) at 3.04 nmol/10⁶ cells, compared to 1.37 nmol/10⁶ cells in the O-342 cells. The increased glutathione levels are associated with enhanced detoxification capabilities, contributing to the chemoresistance observed in the O-342/DDP cells. Additionally, following cisplatin treatment, DNA interstrand crosslinks and single-strand breaks are markedly higher in the parental O-342 cells than in the resistant O-342/DDP cells, indicating an increased DNA repair capacity in the resistant subline.

Overall, the O-342 cell line, along with its cisplatin-resistant subline O-342/DDP, provides a robust model for investigating the mechanisms of chemoresistance in ovarian cancer. These cell lines are invaluable for identifying potential therapeutic targets and developing strategies to overcome resistance to chemotherapy, thereby improving treatment outcomes for ovarian cancer patients.

37°C, 5% CO₂, humidified atmosphere.

1. Confirm that the vial remains deeply frozen upon delivery, as cells are shipped on dry ice to maintain optimal temperatures during transit.

2. Upon receipt, either store the cryovial immediately at temperatures below -150°C to ensure the preservation of cellular integrity, or proceed to step 3 if immediate culturing is required.

3. For immediate culturing, swiftly thaw the vial by immersing it in a 37°C water bath with clean water and an antimicrobial agent, agitating gently for 40-60 seconds until a small ice clump remains.

4. Perform all subsequent steps under sterile conditions in a flow hood, disinfecting the cryovial with 70% ethanol before opening.

5. Carefully open the disinfected vial and transfer the cell suspension into a 15 ml centrifuge tube containing 8 ml of room-temperature culture medium, mixing gently.

6. Centrifuge the mixture at 300 x g for 3 minutes to separate the cells and carefully discard the supernatant containing residual freezing medium.

7. Gently resuspend the cell pellet in 10 ml of fresh culture medium. For adherent cells, divide the suspension between two T25 culture flasks; for suspension cultures, transfer all the medium into one T25 flask to promote effective cell interaction and growth.

8. Adhere to established subculture protocols for continued growth and maintenance of the cell line, ensuring reliable experimental outcomes.

Mycoplasma contamination is excluded using both PCR-based assays and luminescence-based mycoplasma detection methods.

To ensure there is no bacterial, fungal, or yeast contamination, cell cultures are subjected to daily visual inspections.

For long-term preservation, place vials in vapor-phase liquid nitrogen at about −150 to −196 °C. Storage at −80 °C is acceptable only as a short interim step before transfer to liquid nitrogen.

Cryopreserved cell lines are shipped on dry ice in validated, insulated packaging with sufficient refrigerant to maintain approximately −78 °C throughout transit. On receipt, inspect the container immediately and transfer vials without delay to appropriate storage.

At Cytion, we stand behind the quality and viability of our products. We guarantee that our cells will be viable at the start of culture for 60 days after shipment from our facilities. We assure that all materials conform to the specifications described in the Certificate of Analysis and/or Product Sheet.

For full details, please refer to our Warranty Statement.