Probiotics have been evaluated as therapeutic agents for cancer treatment in an increasing number of studies. This study investigated the inhibitory and cytotoxic effects of specific Lactobacillus strains on a human colorectal adenocarcinoma cell line (HT-29). The strains assessed were Limosilactobacillus (L.) reuteri VA 102, Ligilactobacillus (L.) animalis VA 105, and Limosilactobacillus (L.) reuteri KCTC 3594 (ATCC 23272). The viability of HT-29 cells was evaluated using the MTT assay. The findings revealed that cell-free supernatants (CFS) exhibited significant anticancer effects. Heat-inactivated L. reuteri VA 105 and L. reuteri KCTC 3594 induced a pronounced reduction in cell viability. Furthermore, live cultures of L. reuteri VA 105 and L. reuteri VA 102 also showed reduced cell viability compared to the control group. These results suggest that CFS and heat-inactivated cells may be more suitable for therapeutic applications than live bacteria owing to their improved safety profiles and reduced potential for adverse effects. Our findings also emphasize the potential anticancer benefits of these LAB strains.

Lactobacillus is a probiotics that improves various diseases and enhances immunity through the activation of cytokines involved in natural immunity. A variety of studies on immunoregulation have been conducted on various Lactobacillus, but few on Lactobacillus johnsonii (Lj) and especially on immune cells. In this study, we investigated how Lj affects the viability and function of RAW264.7 macrophages. The results indicated that Lj decreased the metabolic activity of RAW 264.7 cells and caused a decrease in the number of cells. In Annexin V and PI staining, the viable cells was significantly decreased at 107 cfu/mL Lj concentration. Measurement of cytokines using enzyme-linked immunosorbent assay (ELISA) showed that Lj increased the production of tumor necrosis factor (TNF)-alpha. Also, Lj increased the expression of CD40 and CD86, confirmed by flow cytometry analysis. Taken together, Lj caused decreased metabolic activity and cell viability, but simultaneously increased the expression of macrophage activation markers and TNF-alpha production. Therefore, when an appropriate dosage of Lj is administered, it is expected that the necessary immunomodulation can be increased while minimizing damage on cells. This study provided evidences for the immunomodulatory effects of Lj on RAW 264.7 cells in vitro and is expected to be a valuable information for Lj research.

Probiotic lactic acid bacteria are live microorganisms that provide health benefits when administered in adequate amounts and may exhibit antiproliferative effects on various cancer cell lines, including colon cancer. This study investigates the cytotoxic effects of three Lactobacillus strains - Limosilactobacillus (L.) reuteri VA 102, Ligilactobacillus (L.) animalis VA 105, and Limosilactobacillus (L.) reuteri KCTC 3594 (ATCC 23272) - on mouse colon carcinoma cells (CT-26). Live cells, heat-killed cells, and cell-free supernatant (CFS) of Lactobacillus sp. were prepared and used to treat CT-26 cells at different concentrations. The cytotoxic effect was assessed using the MTT assay. The results indicated that the CFS of all strains significantly reduced the viability of CT-26 cells in a dose-dependent manner, with the VA 102 strain showing the most pronounced effect. Heat-killed cells of L. reuteri VA 102 and L. reuteri KCTC 3594 (ATCC 23272) also reduced cell viability. These findings suggest the potential anticancer properties of these Lactobacillus strains and indicate that CFS and heat-killed cells may offer a safer and more effective alternative to live bacteria for therapeutic applications. Our study contributes to the understanding of the potential of Lactobacillus strains, particularly L. reuteri VA 102, L. reuteri KCTC 3594 (ATCC 23272), and L. animalis VA 105, as possible candidates for cancer treatment and control.

본 연구에서는 유기질막에 비해 안정성이 우수하고 사용수명이 긴 세라믹 막을 이용하여 혐기성 Lactobacillus 균주의 농축에 관해서 연구하였다. Cell harvesting (CH)에 영향을 주는 인자로 막투과 압력, 온도, 선속도 등에 대해 조사하였으며 세라믹 막을 이용하여 농축율 변화에 따른 플럭스와 TMP (transmembrane pressure)의 변화, 일정 VCF(volumetric concentration factor)에서 TMP변화 등의 최적조건에 관해 알아보았다. 그 결과 플럭스는 TMP, 선속도, VCF가 증가함에 따라 투과수량도 증가함을 알 수 있었다. 온도가 증가할수록 점도에 의해 초기 플럭스도 증가하지만 시간이 경과함에 따라 막 표면의 겔층의 형성으로 온도의 영향은 미미하였다. 또한 농축비 이하의 일정한 VCF에서 운전할 경우 플럭스가 안정적임을 알 수 있었다. 선속도 5 m/s, 공급액의 온도 37^℃, TMP 1 bar에서 6∼8 h 운전할 경우 PS 406 원액의 생균수는 4.9×10^9으로 약 8배 농축됨을 알 수 있었다.

In the present work we investigated the effects of lactic acid bacteria (LAB) isolated from kimchi on prolifera-tion and apoptosis of cancer cells. The cell-free supernatant concentrate of Lactobacillus brevis OPK-3 significantly retar-ded the proliferation of human acute promyelocytic (HL60), human histiocytic (U937), and mouse lymphocytic (L1210)leukemia cell lines in vitro at concentrations over 2.25-9.0 mg/mL. The treatments of the concentrate leaded to the increasedapoptosis and decreased mitochondrial transmembrane potential in cultured U937 leukemia cell lines. In addition, the treat-ments of the concentrate showed the increased expression of p53 gene in cultured U937 and HL60 leukemia cell lines. Onthe other hand, the cell-free supernatant concentrate of control L. brevis strain (KCCM 41028) showed a relatively littleeffect on the cancer cell proliferation, apoptosis, and mitochondrial transmembrane potential at the similar concentrationranges compared with the L. brevis OPK-3 samples. These results suggest that the consumption of L. brevis OPK-3 could bebeneficial for the inhibitory action on leukemia cell proliferation and for the stimulatory action on the cancer cell apoptosis.