In zero. On day 14, the TNF-? concentration reached

In the present work, TNF-?
production and secretion by induced MNCs was measured in culture supernatant at
the beginning of the study, day zero, and at the end of it, day 14. The results
showed that TNF-? was Nil on day zero. On day 14, the TNF-?
concentration reached up to 14.538 ± 6.672 pg/mL. The present results were
supported by those demonstrated by Zhang et al. (58) who
investigated the secretion of TNF-? from expanded umbilical cord – CIK cells.
The result reported was much less than that of our study (6 ± 5.5 pg/mL), which
may be due to different CIK cells origin or the usage of fetal calf serum that
should not be used in immunological studies (46).

            The
CIK cells’ cytotoxic effect on cancerous cells showed variable degrees of
efficacy in several tumors including malignant lymphoma either Hodgkin’s
disease or non-Hodgkin’s lymphoma (NHL) (69), hematological malignancies
as acute myeloid and acute lymphocytic leukemia (70) and chronic
lymphocytic leukemia (CLL) (71). Recent in vitro studies has further
showed the potential activity of CIK cells differentiated from blood of healthy
or patient volunteers against breast cancer (68),   pancreatic cancer (72), ovarian
cancer (73), sarcomas (74), metastatic melanoma (75),
glioblastoma or brain cancer (76) solid tumors (67) and
gallbladder cancer (7).

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            Over
the past few years, CIK cell has entered clinical trials as adjuvant therapy
with promising efficacy for colorectal cancer (78), endometrial
cancer (79), pancreatic cancer (80), gastric cancer (81),
non small cell lung cancer (82), metastatic nasopharyngeal carcinoma
(83), Metastatic renal carcinoma (84), hematological malignancies
(69, 70) and solid tumors (85).

            In
the current study, we examined the cytotoxic effect of mature CIK cells on day
14 on HCC cells in vitro. Our results showed that there was a
significant increase in HepG2 cytotoxicity with the increase in CIK: HepG2
ratio. The cytotoxic effect of CIK cells was maximal at 40:1 ratio, where the
tumor cell killing ability was 58.889 ± 1.104%. This finding was in line with
Wang et al. (30) and Yu et al. (35), who
reported the strong cytolytic activities of CIK cells and their ability to
recognize a number of tumors.

CONCLUSION

            Collectively,
the present study has provided data to support the ongoing practice of
generating CIK cells from human PB, which is an important and promising
strategy for future work involving HCC immunotherapy. PB-derived MNCs can
differentiate into CIK cells in vitro when cultured in complete nutrient
media containing IFN-?, anti-CD3 antibody and IL-2. The CIK culture showed
different proportions of effector and cytotoxic subsets T cells, NK cells and
NK-T cells. CIK cells showed high functional capacity as evidenced by secretion
of cytokine TNF-? and cytotoxicity against HCC cell line, HepG2.

            This
study provides a simple and cheap strategy for in vitro differentiation
of human PB-derived MNCs into CIK cells. Further studies are also needed to
address whether CIK cells may be integrated into current HCC treatment
protocols as well as CIK cells’ in vivo toxicity to normal and cancerous
cells. Several ongoing clinical trials were performed on the efficacy of CIK
cells on HCC patients with no results available yet (86-92).