Prostate Cancer

Ovarian cancer cell lines A2780 and SKOV-3 were obtained from the institutional Cell Line Core Laboratory of the MD Anderson Cancer Center. Prostate cancer cell lines LNCaP and PC-3 were purchased from the American Type Culture Collection (ATCC, Manassas, VA, USA), as well as the NIH3T3 normal cell line. Ovarian cell lines were grown in RPMI-1640 (Sigma-Aldrich, St. Louis, MO, USA) supplemented with 15% fetal bovine serum (FBS; Life Technologies, Carlsbad, CA, USA), 2.0 g sodium bicarbonate, 0.1% gentamicin solution. LNCaP cells were cultured in RPMI-1640 supplemented with 10% FBS, 1.5 g sodium bicarbonate, 2.5 g glucose, 2.383 g HEPES, 0.11 g sodium pyruvate and 1% penicillin/streptomycin. The PC-3 cell line was grown in DMEM (high glucose) complemented with 10% FBS, 1.5 g sodium bicarbonate, 0.22 g sodium pyruvate and 1% penicillin/streptomycin. NIH3T3 cell line was cultured in DMEM (high glucose) supplemented with 10% FBS, 2.7 g sodium bicarbonate and 1% penicillin/streptomycin. All cell lines were incubated at 37 °C in 5% CO₂. All the other reagents were purchased from Sigma-Aldrich. The cell lines were certified free of mycoplasma (read B/read A ratio below 0.9; see figure S7 in Supplementary Information) using the MycoAlert^® mycoplasma detection kit and MycoAlert^® assay control set (Lonza, Morristown, NJ, USA). Subsection C in Supplementary Information provides details regarding the management and cell counting of these cell lines.

With the idea of an MFH technique limited only to small tumor sizes, a special instrument was needed to deliver the heat in a minimally invasive manner. One potential end use of the LIH is during a laparoscopic procedure, a minimal invasive surgery where the surgeon inserts multiple tube-like instruments (with different functions) through small incisions in the patient’s body [53 –56 (link)]. This instrument was designed with a tube-like structure, considering current laparoscopic instrument designs, and its performance is mainly limited by the magnetic generator parameters and the electrical current flowing through it. The TRIH was designed for prostate cancer malignancies. This instrument could be used to reach the prostate transrectally or to access the prostate by placing it in contact with the perineum. A normal prostate has a volume of approximately 25 cm³. Nevertheless, in cases of benign prostate hyperplasia (BPH) or prostate cancer, the prostate volume can increase to over 30 cm³. This was the rationale behind designing this coil larger than the one in the LIH.
The enclosures for each instrument were designed to have a medical device appearance, while also providing a means to maintain the internal temperature of the coil below 155 °C to avoid damage. Both embodiments were designed using NX software (Siemens, Plano, TX, USA) and were partially constructed by a Zortrax Inkspire 3D printer (Zortrax SA, Olsztyn, Poland) with epoxy-based resin from the same company. The constructs can regulate the coil temperature by circulating water (20 °C–25 °C) throughout the instrument similar as inside MFH coils [57 (link)]. The materials for the LIH design and its measurements were selected considering the dimensions of current laparoscopic instruments. A polycarbonate tubing (⌀_inner = 12.7 mm × ⌀_outer = 15.9 mm × 1.6 mm wall) (Small Parts Inc., Logansport, IN, USA) connected the 3D printed parts (handle and tip). The handle included the water inlet and outlets, as well as a nylon wet-location multi-cord grip (McMaster-Carr, Elmhurst, IL, USA) for the 6 AWG Type 2 Litz wires that connect directly to the circuit. The tip was where the coil was placed and served as a connection point for the Masterflex^® 25 L/S^® inner tubing (Cole-Palmer, Vernon Hills, IL, USA). This ensures that the water flows right into the coil before exiting the instrument. A cap at the tip ensured fast replacement of the coil if a problem was encountered. The overall length of the LIH was approximately 23 cm (see figure 3(a)).
The TRIH design was similar in the parts used, but different in shape. In this case, a tygon flexible tubing (⌀_inner = 25.4 mm × ⌀_outer = 31.8 mm × 3.2 mm wall) (McMaster-Carr, Elmhurst, IL, USA) connected the 3D printed parts (handle and tip). Similar to the LIH, the handle included the water inlet and outlets, as well as the nylon wet-location multi-cord grip for the 6 AWG Type 2 Litz wires that connect directly to the circuit. The tip in this case also enclosed the coil and served as a connection point for the 25 L/S^® inner tubing. This part had a 4-jet nozzle for improved heat removal of this larger coil. This design also had a cap for fast replacement of the coil if a problem was encountered. Because of the 3D printed enclosure, the instrument itself is slightly larger than what we aim to use in the future. However, this does not affect its performance, as the coil has the exact dimensions we designed for. The overall length of the TRIH was approximately 25 cm (see figure 3(b)).