Perforin expression in lymphocytes infiltrated to human colorectal cancer

Gene therapy of prostate cancer using liposomes containing perforin expression vector driven by the promoter of prostate-specific antigen gene

Perforin secreted from cytotoxic lymphocytes plays a critical role in cancer immunosurveillance. The aim of this study was to investigate the therapeutic potential of liposomes containing perforin expression vector driven by the promotor of prostate-specific antigen (PSA). The anti-tumor effect of perforin was analyzed using prostate cancer (PC) PC-3 cells in which perforin expression was controlled by Tet-on system (PC-3PRF cells). Liposomes encapsulating PSA promoter-driven perforin expression vector (pLipo) were constructed for its specific expression in PC. The anti-tumor effect of pLipo was evaluated in vitro using docetaxel-resistant PC 22Rv1 PC cell line, 22Rv1DR, and PC-3 cells in the presence of human peripheral blood mono nuclear cells (PBMCs) and also in vivo using male nude mice bearing 22Rv1DR cell-derived tumor xenograft. Induction of perforin significantly inhibited growth of PC-3PRF cells. Treatment with pLipo induced perforin expression in 22Rv1DR cells expressing PSA but not in PC-3 cells lacking it. Treatment with pLipo at a low concentration was prone to inhibit growth of both cell lines and significantly inhibited growth of 22Rv1DR cells when co-incubated with PBMCs. The combined use of pLipo at a high concentration with PBMCs showed nearly complete inhibition of 22Rv1DR cell growth. Intravenous administration of pLipo via tail vein increased the level of perforin in tumor and serum and significantly decreased the tumor volume. Our results suggest that liposome-mediated PC-specific expression of perforin could be a novel therapy for advanced PC.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

Expression of chemokine receptor CCR5 correlates with the presence of hepatic molecular metastases in K-ras positive human colorectal cancer

BACKGROUND

Molecular metastases are precursors of postoperative recurrence, detected by molecular-biological tools. Chemokines and their receptors contribute to dissemination and local immune recognition. A strong expression of the chemokine receptor CCR5 is associated with non-metastatic colorectal cancer and increased CD8+ T-cell infiltration. The aim of this study was to analyze whether CCR5 expression correlates with the presence of hepatic molecular metastases (MM).

METHODS

Ninety-three patients undergoing elective surgery for colorectal cancer were assessed. The K-ras mutation status was defined by PCR-RFLP, and the CCR5 expression status was analyzed by CCR5-specific reverse transcription (RT-PCR) analysis. Liver biopsy samples had been intra-operatively taken to screen for MM. MM were detected by K-ras-specific PCR-RFLP and nested CK20/GCC RT-PCR. Prevalence of MM was correlated with CCR5 expression status.

RESULTS

Human colorectal cancer harboured K-ras mutations in 53% (codon 12: 47%; codon 13: 6%) of cases. Among K-ras mutants, MM were detected in 27-53% of patients, dependent on the technique applied (K-ras-specific PCR-RFLP assay vs. nested CK20/GCC RT-PCR approach (P = 0.004)). CCR5 expression of K-ras mutants ranged from absent (23/49: 47%), weak (17/49: 35%), intermediate (4/49: 8%) to strong (5/49: 10%). MM were found in 30% of CCR5 negative and in 23% of CCR5 positive cancer patients by the K-ras-specific PCR-RFLP assay. The nested CK20/GCC RT-PCR assay detected MM in 87% of CCR5 negative and in 27% of CCR5 positive colorectal cancer patients (P = 0.00002).

CONCLUSION

Thus, CCR5 expression of the primary cancer might be a valuable biomarker indicating the absence of hepatic molecular metastases.

Low expression of chemokine receptor CCR5 in human colorectal cancer correlates with lymphatic dissemination and reduced CD8+ T-cell infiltration

BACKGROUND

Chemokines and their receptors have been proposed to distinctly contribute to tumor growth, dissemination, and local immune escape. The aim of this study was to evaluate the relevance of the chemokine receptor CCR5 expression for the progression of human colorectal cancer.

METHODS

CCR5 expression was assessed by RT-PCR analysis in 103 colorectal cancer patients. Intensity of CCR5 expression was correlated with both tumor and patient characteristics. Infiltration of tumor margins with CD8(+) T cells in the context of CCR5 expression was analyzed by immunohistochemistry in additional 18 colorectal cancer specimens.

RESULTS

Human colorectal cancer revealed variable intensities of CCR5 expression ranging from absent (48/103: 47%), weak (30/103: 29%), intermediate (13/103: 13%), to strong (12/103: 12%). Absent or weak CCR5 expression was significantly associated with advanced UICC stages (P=0.02) and lymphatic metastasis (P=0.05). In addition, CCR5 expression positively correlated with CD8(+) T-cell infiltration in tumor margins (P=0.001).

CONCLUSION

In summary, intermediate and strong CCR5 expression was significantly associated with nonmetastatic colorectal cancer and increased CD8(+) T-cell infiltration.

Selective infiltration of CCR5+CXCR3+ T lymphocytes in human colorectal carcinoma

T cell infiltration in colorectal cancer is associated with a favorable prognosis, suggesting an occurrence of a certain degree of anti-tumor immunity. T helper type 1 (Th1) and Th2 cells are now known to selectively express CC-chemokine receptor 5 (CCR5)/CXC-chemokine receptor 3 (CXCR3) and CCR4, respectively. To clarify the mechanism of T cell infiltration, we examined in situ expression of these chemokine receptors and their respective chemokine ligands in 40 cases of human colorectal cancer. Immunohistochemistry showed a predominant accumulation of T cells expressing CCR5 and CXCR3 mainly along the invasive margin, whereas those expressing CCR4 were rare. Flow cytometric analysis showed that more than half of CD8(+) T cells and a fraction of CD4(+) cells isolated from fresh tumor tissues co-expressed CCR5 and CXCR3, and CD8(+) T cells and CD4(+) cells predominantly produced interferon-gamma (IFN-gamma) over interleukin-4 (IL-4) after in vitro stimulation. RANTES/CCL5, a ligand of CCR5, was localized within infiltrating CD8(+) T cells in a granular pattern, whereas IP-10/CXCL10, a ligand of CXCR3, was localized in cancer cells and macrophages along the invasive margin. These data were consistent with an active recruitment of T cells expressing CCR5 or CXCR3 into the invasive margin of colorectal cancer. With the previous clinicopathological studies showing a favorable prognostic impact of T cell infiltration in colorectal cancer, our study supports the occurrence of a certain level of Th1-shifted cellular immune responses in human colorectal cancer.

Proliferation of T-cell subsets that contact tumour cells in colorectal cancer

We have investigated the proliferation rates of T-cell subsets in colorectal carcinomas using immunohistochemistry. It was found that the tumour-infiltrating T cells in contact with the tumour cells have a significantly higher frequency of proliferation than those in the stroma. In particular, the CD8+ intraepithelial lymphocytes (T-IEL) within the tumours have a significantly higher frequency of proliferation in comparison with CD8+ T cells in the stromal compartment or in any normal mucosal lymphoid tissues. It is possible that the proliferation of the CD8+ T-IEL may be driven by self-antigens expressed on the tumour cells. The proportion of CD3+ CD7- T cells is increased within carcinomas compared with the normal colon, and a population of CD57+ T cells was observed which is absent from the normal colon. It is possible that these phenotypes are acquired in situ due to repeated stimulation of the T cells by tumour antigens. Intact colorectal carcinoma explants were cultured, and the presence of tumour-infiltrating T cells analysed after 3 days of culture in isolation from the systemic compartments. CD3+ T cells were proliferating (at a low rate) within the explants after 3 days of culture, indicating that they may be sustained by factors present in the tumour microenvironment.

T cell receptor-zeta and granzyme B expression in mononuclear cell infiltrates in normal colon mucosa and colon carcinoma

BACKGROUND

Whereas the presence of a lymphoid infiltrate has been associated with a favourable prognosis in colorectal carcinoma, the proliferative and cytotoxic responses of freshly isolated tumour infiltrating lymphocytes are frequently impaired. In mice, tumour induced immune suppression has been associated with a decreased expression of the zeta-chain of the T cell receptor (TCR)-CD3 complex, and loss of mRNA for granzyme B.

AIM

To compare the expression of TCR-zeta and granzyme B in lymphocytes infiltrating normal colonic mucosa and Duke's A and D colorectal carcinomas.

SPECIMENS

Paraffin wax embedded normal (n = 10) and malignant colonic mucosa (seven Dukes's A, nine Dukes's D).

METHOD

Immunohistochemistry.

RESULTS

The numbers of TCR-zeta + lymphocytes decreased from normal mucosa to Dukes's D carcinomas. In contrast, granzyme B+ lymphocytes were more frequent in Dukes's A carcinomas than in normal mucosa, but disappeared from advanced stage tumours. Granzyme B expressing cells were mainly CD3- (natural killer/lymphokine activated killer cells) in normal mucosa, but CD3+ in tumours, indicating the presence of activated cytotoxic T lymphocytes. In vitro culture of tumour infiltrating lymphocytes rapidly restored the expression of both molecules.

CONCLUSION

The frequency of TCR-zeta + and granzyme B+ lymphocytes is decreased in advanced stage colorectal carcinomas. The restoration of expression during in vitro stimulation suggests the presence of tumour derived suppressive factors in situ.

Perforin and lymphocyte-mediated cytolysis

We have discussed in the previous sections the recent progress made toward elucidating the regulatory mechanism of perforin gene transcription and the domain structure of the perforin molecule. It appears that the expression of perforin is, at least partially, controlled at the transcription level through the interaction between killer cell-specific cis- and trans- acting factors. One of such cognate pairs, NF-P motif (an EBS-homologous motif) and NF-P2 (a killer cell-specific DNA-binding protein), has been described. The regulatory mechanism of gene transcription, however, is likely to involve multiple factors which act in a coordinated fashion to bring about the most efficient expression of perforin limited strictly to activated killer lymphocytes. Through studies using synthetic peptides and recombinant perforins, it has been suggested that the N-terminal region of the perforin molecule is an important, though not the only, domain responsible for the lytic activity. Further studies are warranted to elucidate the role(s) of other potential amphiphilic structures located in the central portion of the perforin molecule in the overall pore-forming activity. The molecular basis underlying the resistance of killer lymphocytes to perforin-mediated lysis still remains an open question. Preliminary results, however, suggest that the surface protein(s) restricted to killer cells may account for their self-protection against perforin. Based on recent studies using perforin-deficient mice, the involvement of perforin in lymphocyte-mediated cytolysis both in vivo and in vitro has been confirmed. Two functional roles, a direct (lytic) and an indirect (endocytosis enhancer; conduit), both of which may contribute critically to the cell-killing event can be attributed to perforin. The fact that lymphocytes may also employ perforin-independent killing mechanism(s), e.g. Fas-dependent pathway, is beyond the scope of this review. There is, nevertheless, no doubt that these alternative cytolytic mechanisms may also play important roles in immune effector and/or regulatory responses associated with killer lymphocytes. Obviously, we are still a long way from concluding on the functional relevance of each individual cytolytic mechanism seen in different physiopathological situations. Suffice it to say, however, that a wealth of information on lymphocyte-mediated killing has already emerged through the multidisciplinary efforts conducted in our and other laboratories that promise to further dissect this complicated event in the years to come.

Immunohistochemical analysis of perforin and granzyme A in inflammatory myopathies

Perforin (PF) and granzyme A (GA) are candidates suspected of being cytolytic proteins of the granules of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. We analysed PF and GA in muscles from patients with inflammatory myopathies. Five cases of polymyositis (PM), two cases of inclusion body myositis (IBM), and five cases of dermatomyositis (DM) were studied immunohistochemically using anti-PF and GA antibodies raised against each synthetic peptide of human PF and mouse GA, together with a panel of monoclonal antibodies reactive for lymphocyte subsets. In PM and IBM, PF positive cells were colocalized with GA positive cells and occasionally invaded into the non-necrotic muscle fibres. The percentage of PF positive cells among the endomysial CD8 positive cell population was 9.9% (PM) and 12.5% (IBM), and the majority of the endomysial CD8 positive cells were alpha/beta T cells. In contrast, in DM, both PF and GA positive cells were very few in all cases. Only few inflammatory cells were CD16+ or CD57+ NK cells among these diseases. Our results suggest that PF and GA are secreted mainly from alpha/beta T cells, and may play a key role in muscle fibre damage in at least some PM and IBM, but not in DM.

Human NK cells in health and disease: clinical, functional, phenotypic and DNA genotypic characteristics

Natural killer (NK) cells are the subject of great current interest because of their possible (in vivo) role in tumour cell surveillance and killing, and because of the potential application of cytokine-modulated NK cells in cancer immunotherapy. In addition, clonal proliferations of NK-associated (NKa) cell populations represent a high proportion of chronic (non-B) lymphoid malignancies and abnormal (both clonal and non-clonal) NKa components are being increasingly reported in association with diverse clinical pictures such as autoimmune disease. This communication extensively reviews what is presently known regarding normal and leukaemic NKa phenotypic diversity, the mechanisms of NK-mediated cytolysis, the role of NK cells in malignancy, and the diagnostic and cellular aspects of malignant NKa proliferations.

Immunohistochemical identification of cytotoxic lymphocytes using human perforin monoclonal antibody

Perforin is a potent cytolytic pore-forming protein expressed in cytoplasmic granules of cytotoxic T lymphocytes and natural killer cells. A new monoclonal antibody raised against human perforin was used to detect both in vitro and in vivo perforin expression in cytotoxic cells. Immunohistochemical analysis of human peripheral blood mononuclear cells cultured in recombinant interleukin-2 (rIL-2) showed strong granular cytoplasmic staining of the IL-2 activated cytotoxic cells. Fresh-frozen tissue sections from patients with heart allograft rejection were also stained. Strong granular cytoplasmic staining of the mononuclear inflammatory infiltrate characteristic for perforin in cardiac allograft rejection was observed. The detection and quantitative analysis of perforin-associated cytotoxic cells by the human anti-perforin monoclonal antibody will help to evaluate the significance of these functionally distinct cytotoxic cells in human tissue.