Molecular linking of HIPEC (Hyperthermic Intraperitoneal Chemotherapy) and T-regulatory cells (FOXp3) and Th-17 (RORɣ) in advanced epithelial ovarian cancer

Background

Despite of multimodality treatment of Ovarian Cancer (OC), about two-thirds of patients have peritoneal recurrence with 5-year survival of 15–35%. HIPEC (Hyperthermic Intraperitoneal Chemotherapy) delivers cell-cycle non-specific chemotherapeutic agents along with the temperature of 41°C to 43 °C into the peritoneal cavity after achieving complete cytoreduction, improving overall survival around 50% and recurrence-free survival significantly. Cytoreductive surgery (CRS) and HIPEC may be UpfrontOR Primary - when performed primarily, Interval - when performed after 3 to 6 six cycles of Neo-adjuvant chemotherapy(NACT) and Secondary-when performed for patients who have a recurrence after CRS. OC is associated frequently with tumor-infiltrating lymphocytes in OC microenvironment. Here, we sought to study the interaction of HIPEC on FOXp3 and RORɣ T cells in primary, interval and recurrent settings of HIPEC.

Methodology

We have seen the expression of FOXp3, RORɣ in tumor tissue and surrounding normal tissue of ovarian cancer patients. We also performed IHC of tumor tissue and qRT-PCR of cDNA, isolated from tumor tissue and adjacent normal tissue for the same expression and compared intra-group and among the groups.We studied the expression of FOXp3,RORɣ, Interleukin-10 (IL-10) and Interleukin-17 (IL-17) in peripheral blood mononuclear cells(PBMC) before and after HIPEC in one week and four weeks and compared the changes of expressions.  We included 30 patients with FIGO stage III to IVA advanced Epithelial ovarian cancer patients, with minimum 10 patients in each subgroup i.e.,upfront, interval and secondary. The pilot study was conducted between June 2017 to February 2021 at the premier Institute, India after Ethical approval.

Results

Though there was highest expression of FOXp3 mRNA in recurrent group followed by upfront and interval. However, there was no difference in RORɣ T cell mRNA (by qRT-PCR) expression among three subgroups. We found the change in the expression of FOXp3 and RORɣ T cell in Peripheral blood mononuclear cells by flowcytometry, before and after HIPEC (around 1 week and 4 week after HIPEC) to be significant. In the interval group, there was decreased expression of pre-op Foxp3 compared to the upfront (p = 0.0121) and control (p = 0.0187). These findings suggest that neoadjuvant chemotherapy may reverse the immunosuppressive environment in ovarian cancers. In the upfront group, there was a transient increase of FOXp3 in one week post HIPEC (p = 0.005) and then it decreased to below pre-op values in 4 weeks (p = 0.022). There was no difference in pre-op RORγ and IL 17 among the three subgroups.However, RORγ was increased at four weeks post-HIPEC in the upfront group (p = 0.009), interval group (p = 0.032), and the recurrent group. (p = 0.001). Overall these findings suggest that HIPEC can reverse the immunosuppressive mechanism in ovarian tumor microenvironment (TME),thereby improving survival

Conclusions

In this study, we could come to a conclusion that there is a complex nature of interaction at a molecular and immunological level in epithelial ovarian cancer patients underwent HIPEC in different settings. There is an urgent need to explore bio-molecular markers to improve treatment outcomes of ovarian cancer patients. This basic research study exploring the role of FOXp3 Tregs and RORγ T-helper cells indicated their potential role as biomarkers in understanding ovarian cancer prognosis and the impact of therapeutic interventions like HIPEC in this study, on outcomes.