Establishment and characterization of a novel treatment-related neuroendocrine prostate cancer cell line KUCaP13

The prevalence of neuroendocrine prostate cancer (NEPC) arising from adenocarcinoma (AC) upon potent androgen receptor (AR) pathway inhibition is increasing. Deeper understanding of NEPC biology and development of novel therapeutic agents are needed. However, research is hindered by the paucity of research models, especially cell lines developed from NEPC patients. We established a novel NEPC cell line, KUCaP13, from tissue of a patient initially diagnosed with AC which later recurred as NEPC. The cell line has been maintained permanently in vitro under regular cell culture conditions and is amenable to gene engineering with lentivirus. KUCaP13 cells lack the expression of AR and overexpress NEPC-associated genes, including SOX2, EZH2, AURKA, PEG10, POU3F2, ENO2, and FOXA2. Importantly, the cell line maintains the homozygous deletion of CHD1, which was confirmed in the primary AC of the index patient. Loss of heterozygosity of TP53 and PTEN, and an allelic loss of RB1 with a transcriptomic signature compatible with Rb pathway aberration were revealed. Knockdown of PEG10 using shRNA significantly suppressed growth in vivo. Introduction of luciferase allowed serial monitoring of cells implanted orthotopically or in the renal subcapsule. Although H3K27me was reduced by EZH2 inhibition, reversion to AC was not observed. KUCaP13 is the first patient-derived, treatment-related NEPC cell line with triple loss of tumor suppressors critical for NEPC development through lineage plasticity. It could be valuable in research to deepen the understanding of NEPC.

Lysis of aminobisphosphonate-sensitized MCF-7 breast tumor cells by Vγ9Vδ2 T cells

Aminobisphosphonates are drugs administered for the treatment of bone resorption. They can indirectly activate peripheral γδ T cells and render tumor cells susceptible to lysis by Vγ9Vδ2 T cells. We have investigated the molecules involved in conjugate formation and killing of aminobisphosphonate-treated MCF-7 breast tumor cells by Vγ9Vδ2 T cells. Lysis of aminobisphosphonate (Pamidronate and Zoledronate)-treated MCF-7 tumor cells by Vγ9Vδ2 T cells was assessed by chromium release assays and time-lapse video microscopy. MCF-7 breast cancer cells were chosen as aminobisphosphonates are employed to alleviate bone resorption in this malignancy. Cell cycle profile and expression of MICA, ICAM-I and FasL on aminobisphosphonate-sensitized MCF-7 breast tumor cells was confirmed by flow cytometry. Involvement of γδ TCR and NKG2D in mediating cytotoxicity of aminobisphosphonate-treated MCF-7 breast tumor cells by Vγ9Vδ2 T cells was assessed using blocking antibodies in chromium release assays. MCF-7 tumor cells pretreated with Pamidronate and Zoledronate were efficiently lysed by Vγ9Vδ2 T cells. Pamidronate and Zoledronate treatment of MCF-7 cells induced S phase arrest and did not alter expression of MICA, ICAM-I and FasL. Blocking γδ TCR and NKG2D on Vγ9Vδ2 T cells inhibited lysis of Pamidronate and Zoledronate-treated MCF-7 cells. Inhibiting the perforin-granzyme pathway in Vγ9Vδ2 T cells using concanamycin A reduced their ability to lyse aminobisphosphonate-treated MCF-7 cells. Vγ9Vδ2 T cells form strong conjugates with aminobisphosphonate-treated MCF-7 breast tumor cells. γδ TCR, NKG2D and perforin-granzyme pathway are involved in the lysis of MCF-7 breast tumor cells treated with aminobisphosphonates by Vγ9Vδ2 T cells.

Intestinal trefoil factor confers colonic epithelial resistance to apoptosis

Intestinal trefoil factor (ITF) is an essential regulator of colonic epithelial restitution, the rapid migration of colonocytes over mucosal wounds. High levels of ITF are frequently present in colorectal cancers and derived cell lines. Mucosal restitution requires the detachment of epithelium from substrate, which would be expected to induce apoptosis. However, mice deficient in ITF showed an increase in colonocyte apoptosis unaccompanied by changes in expression of receptor-related (TNFR/Fas) or stress-related (Bcl-family) cell death regulators. An ITF-expressing colonic (HT-ITF1) cell line was resistant to apoptosis induced by serum starvation and ceramide. Exogenous ITF also protected another human colonic carcinoma-derived cell line (HCT116) and a nontransformed rat intestinal epithelial cell line (IEC-6) from apoptosis. This effect was abrogated by wortmannin and tyrphostin A25, indicating the potential involvement of phosphatidylinositol 3-kinase and epidermal growth factor (EGF) receptor activation. Expression of phosphorylated Akt, which lies downstream of phosphatidylinositol 3-kinase activation, was elevated in this HT-29-ITF line. p53-dependent cell death in the AGS human gastric cancer cell line after etoposide was similarly inhibited by transient expression of ITF but not a C-terminal truncation mutant of ITF, and it required functional phosphatidylinositol 3-kinase and EGF receptor. These findings support a central role for ITF in the maintenance of intestinal mucosal continuity, and conversely demonstrate the potential for ITF expression to confer resistance of colorectal tumors to therapy.