Expert Insights | Practical Tips for 786-0 Cell Culture and Gene Editing

The 786-O human renal clear cell adenocarcinoma cells are derived from a primary clear cell carcinoma of a 58-year-old Caucasian male. The cells possess both microvilli and desmosomes and are capable of growing in soft agar. These cells produce a PTH-like peptide that is identical to the peptides produced by breast and lung tumors. This peptide shares a similar N-terminal sequence with PTH, exhibits PTH-like activity, and has a molecular weight of 6,000 Daltons. It has been reported that these cells can form tumors in immunosuppressed hamsters. This document provides exclusive culture techniques for 786-O cells, offering a comprehensive guide to mastering 786-O cell culture and key gene editing practices.

I. Overview of Human Renal Clear Cell Adenocarcinoma Cells (786-O)

• Cell Name: Human Renal Clear Cell Adenocarcinoma Cells (786-O)
• Cell Morphology: Epithelial-like cells, adherent growth
• Culture Medium: 90% RPMI-1640 + 10% FBS
• Atmosphere: Air, 95%; Carbon dioxide, 5%
• Temperature: 37°C
• Medium Renewal Frequency: Every 2–3 days
• Passage Ratio: 1:2 – 1:4

Reference for Cell Growth Status

Normal Morphology: Adherent growth exhibiting epithelial-like morphology, polygonal or irregular shapes, rich cytoplasm, and may contain vacuoles. (See images below)

Abnormal Morphology: Cell outlines appear blurred; cells may change from spindle-shaped or polygonal to round, oval, or irregular shapes; cell volume may shrink or enlarge. (See images below)

II. 786-O Cell Thawing Procedure

• Prepare Culture Medium
  Add 7 mL of complete culture medium to a centrifuge tube and keep it ready.
• Cell Thawing
  Remove the vial from dry ice. Using forceps, hold the vial cap and immerse it in a 37°C water bath. Shake gently (ensure the cap remains above the water surface). Thaw quickly for approximately 1 minute until only a small ice crystal remains. Stop water bath.
• Centrifuge Cells
  Transfer the thawed cell suspension to a centrifuge tube. Centrifuge at 1100 rpm for 4 minutes and discard the supernatant.
• Resuspend and Seed Cells
  Resuspend the cell pellet in complete culture medium and seed into an appropriately sized culture dish or flask.
• Culture Cells
  Place the culture dish or flask in a 37°C incubator. After 24 hours, observe cell attachment and morphology.

III. 786-O Cell Subculture Procedure

• Subculture Conditions
  Subculture cells when they reach 80–90% confluency.
  In a biosafety cabinet, discard the culture medium and wash the cells 1–2 times with 5 mL PBS.
• Trypsin Digestion
  Add 1 mL of trypsin, gently swirl the flask to ensure the enzyme fully covers the cells.
  Place the flask in a incubator for 2-3 minutes.
  Under a microscope, when most cells become round and bright, gently tap the sides of the flask to detach cells, and immediately stop the digestion.
• Terminate Digestion
  Add 2 mL of complete culture medium (2× the volume of trypsin) to stop the reaction.
  Transfer the cell suspension to a 15 mL centrifuge tube.
• Centrifuge Cell Suspension
  Centrifuge at 1100 rpm at room temperature for 4 minutes.
  Discard the supernatant and resuspend the cell pellet in complete culture medium.
• Subculture and Culture
  Seed cells at a split ratio of 1:2 – 1:4. A split ratio of 1:2 is recommended for the initial passage.
  Observe cell morphology and attachment the next day.

IV. 786-O Cell Cryopreservation Procedure

• Collect Cells
  Harvest trypsinized cells following the standard subculture procedure and transfer them into a centrifuge tube.
• Centrifugation
  Centrifuge at 1100 rpm for 4 minutes and discard the supernatant.
• Resuspend and Aliquot for Freezing
  Resuspend the cell pellet in cryopreservation medium. Adjust the concentration to 1×10^6 cells/mL and aliquot 1 mL per cryovial.
  Label each vial with cell line name, passage number, and date.
• Cooling and Storage
  Place the vials in a controlled-rate freezing container and store overnight at -80°C.
  Transfer the vials into liquid nitrogen for long-term storage.

V. Precautions for 786-O Cell Culture

• Cell Confluency: Subculture cells at 80-90% confluency for optimal growth. For growing cells, renew with fresh complete culture medium every 2–3 days.

• Medium Storage: Ensure the culture medium is stored at 4°C, protected from light, and used within its expiration date.

• Strictly Adhere to Basic Culture Conditions: Ensure a normal cell culture environment and utilize the correct culture system.

• Operational Details: Pre-warm culture medium and trypsin to 37°C prior to use to avoid thermal stress.

• High-quality Serum: High-quality fetal bovine serum (FBS) is highly recommended for culture.

VI. Precautions for 786-O Cell Transfection

• Cell Condition Requirements
  • Ensure cells are healthy and in the logarithmic growth phase, with 70-80% confluency.
  • Cell viability should be >90%, which can be assessed using Trypan Blue exclusion.
  • Use low-passage cells.
  • Carefully monitor trypsinization time to avoid over-digestion and cell damage.
  • During the procedure, generate a single-cell suspension and avoid cell clumping.
• Transfection Reagents and Pre-Experiment
  • Mix transfection reagents thoroughly before use to ensure uniformity.
  • Perform preliminary antibiotics-selection experiments to determine the optimal selection concentration post-transfection.
• Electroporation
  • Control the number of cells and seed them into appropriately sized culture plates after electroporation.
  • Use gentle trypsin and terminate digestion completely with serum-containing medium.
  • Wash cells 1–2 times with PBS to completely remove residual serum, preventing ionic interference with electroporation.
  • Optimize electroporation parameters through preliminary experiments.
  • Ensure post-electroporation cell attachment rate is ≥60%.
  • Keep total electroporation time short to avoid excessive stress.
• Lentiviral Transduction
  • Perform preliminary experiments to determine the optimal MOI.
  • Seed cells 18–24 hours prior to transduction; maintain cell confluency at 30–40% before virus infection, avoiding over-confluency.
  • Add transduction adjuvant Polybrene prior to infection.
  • Perform medium renewal 24 hours post-infection.
  • Avoid repeated freezing and thawing of the viral stock used for infection.
  • If transduction efficiency is too low, perform a secondary infection (ensure cells have good tolerance to the virus) or try spinoculation/centrifugal infection.

VII. Precautions for 786-O Single-Clone Seeding Experiments

• Cell Condition Requirements:
  • Use cells in the logarithmic growth phase for single-clone seeding, and the confluency prior to seeding is recommended to be controlled at around 70%.
  • When cells are in optimal health, the viability for clone seeding is generally ≥90%.
• Reagents and Pre-Experiment:
  • Pre-warm all reagents (including culture medium and PBS) prior to the experiment.
  • The use of gentle dissociation reagents (such as TrypLE Express) is recommended.
• Seeding Strategy:
  • Conduct preliminary experiments to determine the optimal seeding density gradient, avoiding too low a single-clone formation rate.
  • When seeding 96-well plates, ensure even cell distribution. Fill the outer wells with PBS to prevent evaporation.
• Dilution Method:
  • Employ the limiting dilution method for single-clone seeding.
  • After cell counting and dilution, the optimal cell count should fall within 1×10^6 to 2×10^6 cells.
  

  Cell Images After lentiviral infection

  

  Single-Clone Cell Image