{
  "abstract": "Background Colorectal cancer (CRC) is a significant global health issue. Response rate to immune checkpoint inhibitors (ICI) in MSI-H CRC patients have been encouraging but highly variable, pointing to the need for a better response biomarker for patient selection. We employed the Farcast CRC TruTumor histoculture platform to understand the role and response of immune cell types in the complex Tumor MicroEnvironment (TME) that could identify ICI therapy responders more accurately.Methods Freshly resected tumor tissue samples along with matched blood were collected from consented patients. Tumor explants were generated and distributed into arms and cultured for 72 h with media replenished every 24h. The response to T-cell stimulation with anti-CD3 (100 ng/mL) + Interleukin-2 (IL-2, 100 IU/mL) and treatment with Nivolumab (132 µg/mL) was evaluated using cytokine release and flow cytometry based immune profiling.Results The CRC TME (n=6) was compared with other indications, namely, Head and Neck Carcinoma (HNSCC: n=10), Renal Cell Carcinoma (RCC: n=10) and Breast Carcinoma (CaBr: n=10). Though the proportion of effector cell populations like (Cytotoxic T-cells (CD8+), Natural killer T cells (CD3+CD56+) and Natural killer cells (CD3-CD56+)) were present in CRC, the activated effector cell (Granzyme B+; GZMB+) proportions were significantly lower. Interestingly, the proportion of Natural Killer (NK) and NK T-cell proportions were higher in CRC and RCC than the other two indications. Additionally, macrophages were biased towards M2 like in CRC compared to other indications. Upon stimulating the tumor fragments with anti-CD3+IL2, CRC samples (n=5) showed only modest increase in the activation (mean value <10%) which was significantly lower (p<0.05) than the other 3 indications.Despite presence of comparable proportions of exhausted CTL population (CD8+PD1+); the target for nivolumab, in CRC (n=4), RCC (n=2) and CaBr (n=3), Nivolumab treatment induced increase in proportion of activated effector immune cells was much more robust in RCC and CaBr compared to CRC. Of the 4 CRC samples treated with nivolumab 2 (S2 and S4) showed more than 1.1-fold increase in GZMB release. Of the two, in S4 there was 3.7-fold increase in IFN-γ secretion with 1.6-fold increase in Perforin release without exhibiting treatment driven tumor cytotoxicity.Conclusions The TruTumor platform reproduced the immunosuppressive TME in CRC and points to the presence of dysfunctional or irreversibly exhausted CTLs that restricts the efficacy of ICI monotherapy. It also provides the opportunity to explore combination therapy strategies to overcome the shortcoming of ICI monotherapy for better outcomes.Ethics Approval Donor tissue specimens along with matched blood sample were obtained from consented patients. Institutional Ethics Committee (IEC) from the sample collection centers approved the protocol (protocol # FCB-PROTOCOL-01) and informed consent for participation in the approved study was obtained from every donor.",
  "authors": [
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Satish Sankaran"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "M Dharanidharan"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Biswajit Das"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Kowshik Jaganathan"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "V Syamkumar"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Chandan Bhowal"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "M Mouniss"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "S Saikrishna"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Abdul Haseeb"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Moumita Nath"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "M Rajashekar"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "M Oliyarasi"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Priyanka Chevour"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Méhul Kapur"
    },
    {
      "affiliations": [
        "DBR and SK Super Speciality Hospital, Tirupati, Andhra Pradesh, India"
      ],
      "name": "C Jaya Prakash"
    },
    {
      "affiliations": [
        "Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India"
      ],
      "name": "MS Ganesh"
    },
    {
      "affiliations": [
        "Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India"
      ],
      "name": "Amritha Prabha"
    },
    {
      "affiliations": [
        "Sri Lakshmi Multi Speciality Hospital, Bangalore, India"
      ],
      "name": "BV Prakash"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Upendra Kumar"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Ritu Malhotra"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "K Govindraj"
    },
    {
      "affiliations": [
        "Farcast Biosciences India Pvt Ltd, Bangalore, Karnataka, India"
      ],
      "name": "Pavithra"
    },
    {
      "affiliations": [
        "Farcast Biosciences, Pensacola, FL, USA"
      ],
      "name": "Mohit Malhotra"
    }
  ],
  "title": "475 Understanding the role of tumor immune microenvironment in determining response to immune checkpoint inhibitor in colorectal cancer",
  "uid": "283033f3-ef6a-5b9e-b8d4-3ca19eaf7065"
}